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WO2020183838A1 - Vehicle steering device - Google Patents

Vehicle steering device Download PDF

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Publication number
WO2020183838A1
WO2020183838A1 PCT/JP2019/049288 JP2019049288W WO2020183838A1 WO 2020183838 A1 WO2020183838 A1 WO 2020183838A1 JP 2019049288 W JP2019049288 W JP 2019049288W WO 2020183838 A1 WO2020183838 A1 WO 2020183838A1
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WO
WIPO (PCT)
Prior art keywords
steering
unit
torque
angle
target
Prior art date
Application number
PCT/JP2019/049288
Other languages
French (fr)
Japanese (ja)
Inventor
貴弘 椿
浩保 熊谷
Original Assignee
日本精工株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日本精工株式会社 filed Critical 日本精工株式会社
Priority to JP2021505524A priority Critical patent/JPWO2020183838A1/en
Publication of WO2020183838A1 publication Critical patent/WO2020183838A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits

Definitions

  • the present invention relates to a high-performance steering device for a vehicle that realizes a desired steering torque based on a torsion angle of a torsion bar or the like, is not affected by a road surface condition, and is not affected by changes in mechanical characteristics over time.
  • the electric power steering device which is one of the steering devices for vehicles, applies an assist force (steering assist force) to the steering system of the vehicle by the rotational force of the motor, and uses the power supplied from the inverter.
  • the driving force of the controlled motor is applied to the steering shaft or rack shaft as an assisting force by a transmission mechanism including a reduction mechanism.
  • feedback control of the motor current is performed in order to accurately generate an assist force.
  • the feedback control adjusts the motor applied voltage so that the difference between the steering assist command value (current command value) and the motor current detection value becomes small, and the adjustment of the motor applied voltage is generally PWM (pulse width). Modulation) Control duty is adjusted.
  • the column shaft (steering shaft, handle shaft) 2 of the handle 1 has a reduction mechanism 3, universal joints 4a and 4b, a pinion rack mechanism 5, and a tie rod 6a. It is further connected to the steering wheels 8L and 8R via the hub units 7a and 7b via 6b. Further, the column shaft 2 having the torsion bar is provided with a torque sensor 10 for detecting the steering torque Ts of the steering wheel 1 and a steering angle sensor 14 for detecting the steering angle ⁇ h, and is a motor that assists the steering force of the steering wheel 1. 20 is connected to the column shaft 2 via the reduction mechanism 3.
  • Electric power is supplied from the battery 13 to the control unit (ECU) 30 that controls the electric power steering device, and an ignition key signal is input via the ignition key 11.
  • the control unit 30 calculates the current command value of the assist (steering assistance) command based on the steering torque Ts detected by the torque sensor 10 and the vehicle speed Vs detected by the vehicle speed sensor 12, and compensates the current command value.
  • the current supplied to the EPS motor 20 is controlled by the voltage control command value Vref.
  • a CAN (Controller Area Network) 40 that exchanges various vehicle information is connected to the control unit 30, and the vehicle speed Vs can also be received from the CAN 40. Further, a non-CAN 41 that transmits / receives communications other than CAN 40, analog / digital signals, radio waves, etc. can also be connected to the control unit 30.
  • the control unit 30 is mainly composed of a CPU (including an MCU, an MPU, etc.), and FIG. 2 shows a general function executed by a program inside the CPU.
  • the steering torque Ts detected by the torque sensor 10 and the vehicle speed Vs detected by the vehicle speed sensor 12 are the current command value calculation unit. It is input to 31.
  • the current command value calculation unit 31 calculates the current command value Iref1, which is the control target value of the current supplied to the motor 20, by using the assist map or the like based on the input steering torque Ts and vehicle speed Vs.
  • Irefm-Im is calculated, and the deviation I is input to the PI (proportional integration) control unit 35 for improving the characteristics of the steering operation.
  • the voltage control command value Vref whose characteristics have been improved by the PI control unit 35 is input to the PWM control unit 36, and the motor 20 is PWM-driven via the inverter 37 as the drive unit.
  • the current value Im of the motor 20 is detected by the motor current detector 38 and fed back to the subtraction unit 32B.
  • the compensation signal CM from the compensation signal generation unit 34 is added to the addition unit 32A, and the characteristics of the steering system system are compensated by adding the compensation signal CM to improve the astringency, inertial characteristics, and the like. ..
  • the compensation signal generation unit 34 adds the self-aligning torque (SAT) 343 and the inertia 342 by the addition unit 344, further adds the convergence 341 to the addition result by the addition unit 345, and compensates the addition result of the addition unit 345. It is a signal CM.
  • the steering torque applied manually by the driver is detected by the torque sensor as the torsion torque of the torsion bar, and the assist current mainly corresponding to the torque is detected.
  • the motor current is controlled as.
  • the steering torque may differ depending on the steering angle due to the difference in the road surface condition (for example, inclination).
  • the steering torque may also be affected by variations in motor output characteristics due to aging.
  • Patent Document 1 an electric power steering device as shown in Japanese Patent No. 5208894 (Patent Document 1) has been proposed.
  • the steering angle or the steering torque determined based on the relationship between the steering angle or the steering torque and the response amount in order to give an appropriate steering torque based on the tactile characteristics of the driver.
  • the target value of steering torque is set based on the relationship (steering reaction force characteristic map).
  • the steering reaction force characteristic map must be obtained in advance, and control is performed based on the deviation between the target value of the steering torque and the detected steering torque. Therefore, there is a possibility that the influence on the steering torque remains.
  • the steering reaction force if the appropriate reaction force is not transmitted to the driver even when the vehicle is stopped and at extremely low speeds, the steering feeling will be felt without resistance, which may give the driver a sense of discomfort.
  • the present invention has been made based on the above circumstances, and an object of the present invention is not affected by the condition of the road surface, not affected by changes in the mechanical characteristics of the steering steering system over time, and with respect to the steering angle and the like. It is an object of the present invention to provide a steering device for a vehicle capable of easily achieving the same steering torque. Further, it is also an object to appropriately convey the steering reaction force at the time of stopping and at extremely low speed to the driver as a steering feeling.
  • the present invention relates to a vehicle steering device that includes at least a torsion bar having an arbitrary spring constant and a sensor that detects a torsion angle of the torsion bar, and assists and controls the steering system by driving and controlling a motor.
  • the object of the above is a target steering torque generating unit that generates a target steering torque, a conversion unit that converts the target steering torque into a target torsion angle, and a motor current that causes the torsion angle to follow the target torsion angle.
  • the target steering torque generating unit includes a torsion angle control unit that calculates a command value, and the target steering torque generating unit includes a steering characteristic correction unit that obtains a first torque signal based on a desired steering characteristic according to the steering angle. This is achieved by outputting the first torque signal as the target steering torque and driving and controlling the motor based on the motor current command value.
  • the stationary characteristic correction unit includes a stationary characteristic calculation unit that obtains a basic torque signal by performing hysteresis correction using the steering state and the steering angle, and obtains the basic torque signal.
  • the stationary characteristic correction unit further includes a vehicle speed-sensitive gain unit that calculates the first torque signal by outputting it as the first torque signal or by multiplying the basic torque signal by the vehicle speed-sensitive gain.
  • a basic map unit to be obtained and a damper calculation unit to obtain a third torque signal based on angular speed information using a damper gain map that is sensitive to vehicle speed are further provided, and the second torque signal and the third torque signal are included.
  • the target steering torque from at least one signal and the first torque signal, or because the basic map is sensitive to vehicle speed, or because the target steering torque generation unit is in front of the basic map unit.
  • a phase compensation unit that performs phase compensation is further provided in the subsequent stage, and the second torque signal is obtained from the steering angle and the vehicle speed via the basic map unit and the phase compensation unit, so that it is more effective. Achieved.
  • the torsion angle follows the target torsion angle by controlling the target torsion angle obtained based on the target steering torque generated by the target steering torque generating unit. It is possible to realize a desired steering torque and to provide an appropriate steering torque based on the driver's steering feeling.
  • the steering reaction force at the time of stopping and at extremely low speed can be appropriately transmitted to the driver as a steering feeling.
  • the present invention is a vehicle steering device for achieving the same steering torque with respect to the steering angle and the like without being affected by the road surface condition, and the torsion angle of the torsion bar and the like is set to a value according to the steering angle and the like.
  • the desired steering torque is realized by controlling so as to follow.
  • the steering angle ⁇ h is detected by a steering angle sensor provided on the upper part of the column shaft 2, and from the deviations of the steering wheel angle ⁇ 1 and the column angle ⁇ 2 , the torsion bar torsion angle ⁇ and torsion bar torque are determined by the following equations 1 and 2. Tt can be calculated. Kt is the spring constant of the torsion bar 2A.
  • the torsion bar torque Tt can also be detected using, for example, a torque sensor disclosed in Japanese Patent Application Laid-Open No. 2008-216172.
  • the torsion bar torque Tt is also treated as the steering torque Ts.
  • FIG. 4 is a block diagram showing a configuration example (first embodiment) of the present invention, in which the driver's steering wheel steering is assist-controlled by a motor in the EPS steering system / vehicle system 100.
  • the vehicle speed Vs and the right-turn or left-turn steering state STs output from the right-turn / left-turn determination unit 500 are input to the target steering torque generation unit 200 that outputs the target steering torque Tref.
  • the target steering torque Tref is converted into a target torsion angle ⁇ ref by the conversion unit 400, and the target torsion angle ⁇ ref is input to the torsion angle control unit 300 together with the torsion angle ⁇ of the torsion bar 2A and the motor angular velocity ⁇ m.
  • the twist angle control unit 300 calculates a motor current command value Imc so that the twist angle ⁇ becomes a target twist angle ⁇ ref, and the motor of the EPS is driven by the motor current command value Imcc.
  • FIG. 5 shows a configuration example of the target steering torque generation unit 200
  • the target steering torque generation unit 200 includes a basic map unit 210, a differentiation unit 220, a damper gain unit 230, a stationary characteristic correction unit 240, a multiplication unit 250, and an addition unit.
  • the steering angle ⁇ h is input to the basic map unit 210, the differential unit 220 and the stationary characteristic correction unit 240
  • the vehicle speed Vs is input to the basic map unit 210, the damper gain unit 230 and the stationary characteristic correction unit 240.
  • the steering state STs output from the right-turn / left-turn determination unit 500 are input to the stationary characteristic correction unit 240.
  • the basic map unit 210 has a basic map, and uses the basic map to output a torque signal (second torque signal) Tref_a having the vehicle speed Vs as a parameter as shown in FIG. That is, the torque signal Tref_a increases as the magnitude (absolute value)
  • the code unit 211 outputs the code (+1 or -1) of the steering angle ⁇ h to the multiplication unit 212.
  • the magnitude of the torque signal Tref_a is obtained from the magnitude of the steering angle ⁇ h by a map, and this is multiplied by the sign of the steering angle ⁇ h to calculate the torque signal Tref_a.
  • a map the code (+1 or -1) of the steering angle ⁇ h
  • the basic map unit 210 is composed of the map, the sign unit, and the multiplication unit that refer to the magnitude
  • the differentiation unit 220 differentiates the steering angle ⁇ h to calculate the steering angle velocity ⁇ h, which is the angular velocity information, and the steering angle velocity ⁇ h is input to the multiplication unit 250.
  • Damper gain unit 230 outputs the damper gain D G is multiplied by the steering angular speed [omega] h.
  • Steering angular velocity ⁇ h which is multiplied by the damper gain D G at multiplying unit 250 is input to the adder 252 as the torque signal (third torque signal) Tref_b.
  • Damper gain D G using the damper gain map of vehicle speed sensitive type having the damper gain unit 230 is determined according to the vehicle speed Vs.
  • the damper gain map has a characteristic that it gradually increases as the vehicle speed Vs increases, as shown in FIG. 7, for example.
  • the damper gain map may be variable according to the steering angle ⁇ h.
  • the damper gain unit 230 and the multiplication unit 250 constitute a damper calculation unit.
  • the stationary characteristic correction unit 240 has a torque that makes the steering torque characteristic (stationary characteristic) desired according to the steering angle ⁇ h in the stationary state in which the steering wheel is steered when the vehicle is stopped and in the steering at extremely low speed.
  • the signal (first torque signal) Tref_c is output.
  • FIG. 8 shows a configuration example of the stationary characteristic correction unit 240.
  • the stationary characteristic correction unit 240 includes a stationary characteristic calculation unit 241 and a vehicle speed sensitive gain unit 242.
  • the stationary characteristic calculation unit 241 calculates the torque signal (basic torque signal) Tref_s according to the following equation 3 based on the steering angle ⁇ h and the steering state STs in order to make the stationary characteristic a hysteresis characteristic.
  • x ⁇ h
  • y Tref_s
  • a> 1 c>
  • a hys is the hysteresis width.
  • the above number 4 can be derived by substituting x1 for x and y1 for y R and y L in the above number 3.
  • any positive number larger than 1 can be used as "a”.
  • the numbers 3 and 4 become the following numbers 5 and 6.
  • FIG. 9 shows an example of a diagram of the torque signal Tref_s. That is, the torque signal Tref_s from the stationary characteristic calculation unit 241 has a hysteresis characteristic such as the origin of 0 ⁇ L1 (thin line) ⁇ L2 (broken line) ⁇ L3 (thick line).
  • a hys which is a coefficient representing the output width of the hysteresis characteristic
  • c which is a coefficient representing roundness
  • the vehicle speed-sensitive gain unit 242 outputs the torque signal Tref_c by multiplying the torque signal Tref_s by the gain corresponding to the vehicle speed (vehicle speed-sensitive gain).
  • the vehicle speed sensitive gain is set so as to decrease as the vehicle speed Vs increases. For example, as shown in FIG. 10, when the vehicle speed Vs is 0 km / h (when the vehicle is stopped), the vehicle speed sensitive gain is set to 2.0 so that the magnitude of the torque signal Tref_s is 2 [Nm], and then the vehicle speed.
  • the vehicle speed sensitive gain decreases at a constant rate, and when the vehicle speed Vs reaches Vs1 (for example, 2 km / h), the decrease rate decreases, and when the vehicle speed Vs is Vs2 (for example, 6 km / h).
  • the vehicle speed sensitive gain is set to 0.
  • the value of the vehicle speed-sensitive gain when the vehicle speed Vs is 0 km / h may be other than 2.0, the rate at which the vehicle speed-sensitive gain decreases may change at multiple locations, and the change in vehicle speed-sensitive gain may be a linear change. It may be a curvilinear change.
  • the stationary characteristic calculation unit 241 gives the stationary characteristic a hysteresis property
  • the vehicle speed sensitive gain unit 242 makes the stationary characteristic vehicle speed sensitive, so that the torque signal Tref_c makes the stationary characteristic a desired characteristic. Is generated, and the torque signal Tref_c makes it possible to appropriately transmit the steering reaction force at the time of stopping and at extremely low speed to the driver as a steering feeling.
  • the vehicle speed sensitive gain unit 242 by varying the hysteresis width A hys according to the vehicle speed Vs, may be vehicle speed sensitive to ⁇ Ri characteristics. In this case, the vehicle speed-sensitive gain unit 242 becomes unnecessary.
  • the coefficient a may also be variable according to the vehicle speed Vs.
  • the stationary characteristic may be a characteristic other than the hysteresis characteristic.
  • the torque signals Tref_c, Tref_b and Tref_a are sequentially added by the addition units 252 and 251 and output as the target steering torque Tref.
  • the rudder angular velocity ⁇ h is obtained by a differential calculation with respect to the steering angle ⁇ h, but a low-pass filter (LPF) process is appropriately performed in order to reduce the influence of high-frequency noise. Further, the differential operation and the LPF processing may be performed by the high-pass filter (HPF) and the gain. Further, the steering angular velocity ⁇ h is calculated by performing differential calculation and LPF processing on the handle angle ⁇ 1 detected by the upper angle sensor or the column angle ⁇ 2 detected by the lower angle sensor instead of the steering angle ⁇ h. Is also good.
  • the motor angular velocity ⁇ m may be used as the angular velocity information instead of the steering angular velocity ⁇ h, and in this case, the differential unit 220 becomes unnecessary.
  • the conversion unit 400 has a characteristic of -1 / Kt in which the sign of the reciprocal of the spring constant Kt of the torsion bar 2A is inverted, and converts the target steering torque Tref into the target torsion angle ⁇ ref.
  • the twist angle control unit 300 calculates the motor current command value Imc based on the target twist angle ⁇ ref, the twist angle ⁇ , and the motor angular velocity ⁇ m.
  • FIG. 11 is a block diagram showing a configuration example of the torsion angle control unit 300, wherein the torsion angle control unit 300 includes a torsion angle feedback (FB) compensation unit 310, a torsion angular velocity calculation unit 320, a speed control unit 330, and a stabilization compensation unit. It includes 340, an output limiting unit 350, a subtracting unit 361, and an adding unit 362.
  • FB torsion angle feedback
  • the target torsional angle ⁇ ref output from the conversion unit 400 is additionally input to the subtracting unit 361, and the twisting angle ⁇ is subtracted and input to the subtracting unit 361. At the same time, it is input to the torsion angular velocity calculation unit 320, and the motor angular velocity ⁇ m is input to the stabilization compensation unit 340.
  • the twist angle FB compensation unit 310 multiplies the compensation value C FB (transfer function) by the deviation ⁇ 0 of the target twist angle ⁇ ref calculated by the subtraction unit 361 and the twist angle ⁇ , and the twist angle ⁇ ref is multiplied by the target twist angle ⁇ ref. Outputs the target torsional velocity ⁇ ref that follows.
  • the compensation value C FB may be a simple gain Kpp or a commonly used compensation value such as a PI control compensation value.
  • the target torsional velocity ⁇ ref is input to the speed control unit 330.
  • the twist angle FB compensation unit 310 and the speed control unit 330 make it possible to make the twist angle ⁇ follow the target twist angle ⁇ ref and realize a desired steering torque.
  • the torsion angular velocity calculation unit 320 calculates the torsion angular velocity ⁇ t by a differential calculation with respect to the torsion angle ⁇ , and the torsion angular velocity ⁇ t is input to the speed control unit 330.
  • a differential operation pseudo-differentiation by HPF and gain may be performed.
  • the torsion angular velocity ⁇ t may be calculated from another means or other than the torsion angle ⁇ and input to the velocity control unit 330.
  • the speed control unit 330 calculates the motor current command value Imca1 so that the torsion angular velocity ⁇ t follows the target torsional velocity ⁇ ref by IP control (proportional leading PI control).
  • the subtraction unit 333 calculates the difference ( ⁇ ref- ⁇ t) between the target torsional velocity ⁇ ref and the torsional angular velocity ⁇ t, integrates the difference with the integration unit 331 having the gain Kvi, and the integration result is additionally input to the subtraction unit 334.
  • the torsion angular velocity ⁇ t is also input to the proportional unit 332, is subjected to proportional processing by the gain Kvp, and is subtracted and input to the subtraction unit 334.
  • the subtraction result in the subtraction unit 334 is output as the motor current command value Imca1.
  • the speed control unit 330 is not an IP control, but a PI control, a P (proportional) control, a PID (proportional integral differential) control, a PI-D control (differential leading PID control), a model matching control, and a model reference.
  • the motor current command value Imca1 may be calculated by a commonly used control method such as control.
  • the stabilization compensation unit 340 has a compensation value Cs (transfer function), and calculates the motor current command value Imca2 from the motor angular velocity ⁇ m. If the gains of the torsion angle FB compensating unit 310 and the speed control unit 330 are increased in order to improve the followability and the disturbance characteristics, a high-frequency controlled oscillation phenomenon occurs. As a countermeasure, the transfer function (Cs) required for stabilizing the motor angular velocity ⁇ m is set in the stabilization compensation unit 340. As a result, it is possible to realize stabilization of the entire EPS control system.
  • the transfer function (Cs) of the stabilization compensation unit 340 for example, a first-order filter represented by the following equation 7 set by pseudo differentiation and gain using the structure of the first-order HPF is used.
  • K sta is a gain
  • fc is a cutoff frequency, and for example, 150 [Hz] is set as fc.
  • s is the Laplace operator.
  • a second-order filter, a fourth-order filter, or the like may be used as the transfer function.
  • the motor current command value Imca1 from the speed control unit 330 and the motor current command value Imca2 from the stabilization compensation unit 340 are added by the addition unit 362 and output as the motor current command value Imccb.
  • the output limiting unit 350 limits the upper and lower limits of the motor current command value Imccb and outputs the motor current command value Imcc.
  • the upper limit value and the lower limit value with respect to the motor current command value are set in advance, and when the input motor current command value Imccb is equal to or more than the upper limit value, the upper limit value is set, and when it is less than the lower limit value, the lower limit value In other cases, the motor current command value Imccb is output as the motor current command value Imcc.
  • the right-turn / left-turn determination unit 500 inputs the motor angular velocity ⁇ m, determines whether the steering is right-turn or left-turn based on the sign of the motor angular velocity ⁇ m, and sets the determination result as the steering state STs. Output to the target steering torque generation unit 200 (step S10).
  • the target steering torque generation unit 200 inputs the steering angle ⁇ h and the vehicle speed Vs together with the steering state STs, and generates the target steering torque Tref (step S20). An operation example of the target steering torque generation unit 200 will be described with reference to the flowchart of FIG.
  • the steering angle ⁇ h input to the target steering torque generation unit 200 is in the basic map unit 210, the differential unit 220 and the stationary characteristic correction unit 240, the steering state STs is in the stationary characteristic correction unit 240, and the vehicle speed Vs is in the basic map unit 210.
  • the basic map unit 210 generates a torque signal Tref_a corresponding to the steering angle ⁇ h and the vehicle speed Vs using the basic map shown in FIG. 6 and outputs the torque signal to the addition unit 251 (step S22).
  • Differentiating section 220 differentiates the steering angle ⁇ h outputs steering angular velocity [omega] h (step S23), damper gain unit 230 outputs the damper gain D G corresponding to the vehicle speed Vs by using the damper gain map shown in FIG 7 (step S24), the multiplication unit 250 calculates a torque signal Tref_b by multiplying the steering angular velocity ⁇ h and damper gain D G, and outputs the result to adding section 252 (step S25).
  • the stationary characteristic correction unit 240 the steering angle ⁇ h and the steering state STs are input to the stationary characteristic calculation unit 241 and the vehicle speed Vs is input to the vehicle speed sensitive gain unit 242.
  • the stationary characteristic calculation unit 241 performs hysteresis correction for the steering angle ⁇ h by switching the calculation according to the equation 5 and the equation 6 according to the steering state STs (step S26), generates the torque signal Tref_s, and responds to the vehicle speed. Output to the gain unit 242.
  • the vehicle speed-sensitive gain unit 242 determines the vehicle speed-sensitive gain according to the characteristics shown in FIG. 10 according to the vehicle speed Vs, multiplies the torque signal Tref_s, and outputs the torque signal Tref_c to the addition unit 252 (step S27).
  • the stationary characteristic calculation unit 241 presets and holds the hysteresis widths A hys , c, x1 and y1 in the equations 5 and 6, but b and b'are calculated in advance from the equation 6 and x1. And b and b'may be retained instead of y1.
  • the torque signals Tref_b and Tref_c are added by the addition unit 252
  • the torque signal Tref_a is added by the addition unit 251 to the addition result
  • the target steering torque Tref is calculated (step S28).
  • the target steering torque Tref generated by the target steering torque generation unit 200 is input to the conversion unit 400, and is converted into the target twist angle ⁇ ref by the conversion unit 400 (step S30).
  • the target twist angle ⁇ ref is input to the twist angle control unit 300.
  • the twist angle control unit 300 inputs the twist angle ⁇ and the motor angular velocity ⁇ m together with the target twist angle ⁇ ref, and calculates the motor current command value Imc (step S40). An operation example of the twist angle control unit 300 will be described with reference to the flowchart of FIG.
  • the target torsion angle ⁇ ref input to the torsion angle control unit 300 is input to the subtraction unit 361, the torsion angle ⁇ is input to the subtraction unit 361 and the torsional velocity calculation unit 320, and the motor angular velocity ⁇ m is input to the stabilization compensation unit 340 (step). S41).
  • the deviation ⁇ 0 is calculated by subtracting the twist angle ⁇ from the target twist angle ⁇ ref (step S42).
  • Deviation [Delta] [theta] 0 is input to the helix angle FB compensation unit 310, the twist angle FB compensation unit 310 compensates the deviation [Delta] [theta] 0 is multiplied by the compensation value C FB on the deviation [Delta] [theta] 0 (step S43), the target torsion angular velocity ⁇ ref Is output to the speed control unit 330.
  • the torsion angular velocity calculation unit 320 that has input the torsion angle ⁇ calculates the torsion angular velocity ⁇ t by a differential calculation with respect to the torsion angle ⁇ (step S44), and outputs the torsion angular velocity ⁇ t to the speed control unit 330.
  • the difference between the target torsional velocity ⁇ ref and the torsional angular velocity ⁇ t is calculated by the subtraction unit 333, and the difference is integrated (Kvi / s) by the integration unit 331 and additionally input to the subtraction unit 334 (step S45).
  • the torsion angular velocity ⁇ t is proportionally processed (Kvp) by the proportional unit 332, the proportional result is subtracted and input to the subtraction unit 334 (step S45), and the motor current command value Imca1 which is the subtraction result of the subtraction unit 334 is output and added. It is input to the unit 362.
  • the stabilization compensation unit 340 performs stabilization compensation on the input motor angular velocity ⁇ m using the transfer function Cs represented by Equation 7 (step S46), and the motor current command value Imca2 from the stabilization compensation unit 340. Is input to the addition unit 362.
  • the addition unit 362 adds the motor current command values Imca1 and Imca2 (step S47), and the motor current command value Imccb, which is the addition result, is input to the output limiting unit 350.
  • the output limiting unit 350 limits the upper and lower limit values of the motor current command value Imccb by the preset upper limit value and lower limit value (step S48), and outputs the motor current command value Imcc (step S49).
  • the motor is driven based on the motor current command value Imcc output from the torsion angle control unit 300, and current control is performed (step S50).
  • FIG. 16 is a conceptual diagram of a diagram showing how the steering angle ⁇ h and the target steering torque Tref change when the vehicle speed Vs is steered at 0 km / h (stationary state).
  • the characteristics of the basic map are that the torque signal Tref_a is proportional to the magnitude of the steering angle ⁇ h
  • is 90 deg, and the torque signal Tref_a is 2 Nm. and then, damper gain D G is set to zero.
  • the hysteresis characteristic of the stationary characteristic calculation unit 241 is the characteristic shown in FIG. 9, and the characteristic of the vehicle speed sensitive gain in the vehicle speed sensitive gain unit 242 is the characteristic shown in FIG. Therefore, substantially, FIG. 16 is a diagram based on a linear basic map and a hysteresis characteristic multiplied by a gain of 2.0.
  • the target steering torque is changed by the function of the stationary characteristic correction unit 240 as shown in FIG. It is possible to realize the diagram characteristics in.
  • the target steering torque generation unit 200 in the first embodiment includes a basic map unit 210, a damper calculation unit (damper gain unit 230 and multiplication unit 250), and a stationary characteristic correction unit 240, but realizes a desired stationary characteristic.
  • a configuration may be configured in which only the stationary characteristic correction unit 240 is provided, specializing only in the stationary characteristic correction unit 240.
  • FIG. 17 shows a configuration example (second embodiment) of the target steering torque generation unit in this case.
  • the torque signal Tref_c output from the stationary characteristic correction unit 240 is output as the target steering torque Tref.
  • the target steering torque generation unit may be configured by combining the basic map unit 210 or the damper calculation unit and the stationary characteristic correction unit 240.
  • the motor current command value Imc output from the torsion angle control unit in the first and second embodiments is referred to as a current command value calculated based on the steering torque in the conventional EPS (hereinafter, referred to as "assist current command value").
  • assist current command value May be added, for example, to the current command value Iref1 output from the current command value calculation unit 31 shown in FIG. 2, or the current command value Iref2 obtained by adding the compensation signal CM to the current command value Iref1.
  • FIG. 18 shows a configuration example (third embodiment) to which the above contents are applied to the first embodiment.
  • the assist control unit 700 includes a current command value calculation unit 31, a current command value calculation unit 31, a compensation signal generation unit 34, and an addition unit 32A.
  • the assist current command value Iac output from the assist control unit 700 (corresponding to the current command value Iref1 or Iref2 in FIG. 2) and the motor current command value Imcc output from the twist angle control unit 300 are added by the addition unit 710.
  • the current command value Ic which is the result of addition, is input to the current limiting unit 720, and the motor is driven based on the current command value Icm in which the maximum current is limited, and current control is performed.
  • the phase compensation unit 260 that performs phase compensation may be inserted in the front stage or the rear stage of the basic map unit 210. That is, the configuration of the region R surrounded by the broken line in FIG. 5 may be configured as shown in FIGS. 19A or 19B.
  • the phase compensation unit 260 when phase advance compensation is set as phase compensation and, for example, phase advance compensation is performed by a primary filter having a numerator cutoff frequency of 1.0 Hz and a denominator cutoff frequency of 1.3 Hz. A refreshing feel can be achieved.
  • the target steering torque generating unit is not limited to the above configuration as long as it has a configuration based on the steering angle.
  • the stabilization compensation unit may be omitted.
  • the output limiting unit can also be omitted.
  • the present invention is applied to the column type EPS in FIGS. 1 and 3, the present invention is not limited to the upstream type such as the column type, and can be applied to the downstream type EPS such as the rack and pinion. Further, by performing feedback control based on the target torsion angle, it can be applied to a steer-by-wire (SBW) reaction force device having at least a torsion bar (arbitrary spring constant) and a sensor for detecting the torsion angle.
  • SBW steer-by-wire
  • FIG. 20 is a diagram showing a configuration example of the SBW system corresponding to a general configuration of the electric power steering device shown in FIG.
  • the same components are designated by the same reference numerals, and detailed description thereof will be omitted.
  • the SBW system is a system that does not have an intermediate shaft that is mechanically coupled to the column shaft 2 by a universal joint 4a, and transmits the operation of the handle 1 to a steering mechanism composed of steering wheels 8L, 8R, etc. by an electric signal. ..
  • the SBW system includes a reaction force device 60 and a drive device 70, and a control unit (ECU) 50 controls both devices.
  • the reaction force device 60 detects the steering angle ⁇ h by the steering angle sensor 14, and at the same time, transmits the motion state of the vehicle transmitted from the steering wheels 8L and 8R to the driver as reaction force torque.
  • the reaction force torque is generated by the reaction force motor 61.
  • the SBW system to which the present invention is applied is a type that has a torsion bar, and the torque sensor 10 detects the steering torque Ts. To do. Further, the angle sensor 74 detects the motor angle ⁇ m of the reaction force motor 61.
  • the drive device 70 drives the drive motor 71 in accordance with the steering of the steering wheel 1 by the driver, applies the driving force to the pinion rack mechanism 5 via the gear 72, and operates the pinion rack mechanism 5 via the tie rods 6a and 6b. Steer the facing wheels 8L and 8R.
  • An angle sensor 73 is arranged in the vicinity of the pinion rack mechanism 5 to detect the steering angle ⁇ t of the steering wheels 8L and 8R.
  • the ECU 50 In order to coordinately control the reaction force device 60 and the drive device 70, the ECU 50 adds information such as steering angle ⁇ h and steering angle ⁇ t output from both devices, and based on vehicle speed Vs from the vehicle speed sensor 12 and the like.
  • the voltage control command value Vref1 that drives and controls the reaction force motor 61 and the voltage control command value Vref2 that drives and controls the drive motor 71 are generated.
  • FIG. 21 is a block diagram showing the configuration of the fourth embodiment.
  • the reaction force device is twisted by controlling the twist angle ⁇ (hereinafter referred to as “twist angle control”) and controlling the steering angle ⁇ t (hereinafter referred to as “turning angle control”). It is controlled by angle control, and the drive unit is controlled by steering angle control.
  • the drive device may be controlled by another control method.
  • the torsion angle ⁇ follows the target torsion angle ⁇ ref calculated through the target steering torque generating unit 200 and the conversion unit 400 using the steering angle ⁇ h and the like by the same configuration and operation as in the first embodiment. Control to do so.
  • the motor angle ⁇ m is detected by the angle sensor 74, and the motor angular velocity ⁇ m is calculated by differentiating the motor angle ⁇ m by the angular velocity calculation unit 951.
  • the steering angle ⁇ t is detected by the angle sensor 73.
  • the current control unit 130 includes the subtraction unit 32B, the PI control unit 35, and the PWM control shown in FIG.
  • the target steering angle generation unit 910 In the steering angle control, the target steering angle generation unit 910 generates a target steering angle ⁇ tref based on the steering angle ⁇ h, and the target steering angle ⁇ tref is input to the steering angle control unit 920 together with the steering angle ⁇ t.
  • the steering angle control unit 920 calculates the motor current command value Imct so that the steering angle ⁇ t becomes the target steering angle ⁇ tref. Then, based on the motor current command value Imct and the current value Imd of the drive motor 71 detected by the motor current detector 940, the current control unit 930 has the same configuration and operation as the current control unit 130, and the drive motor has the same configuration and operation.
  • the 71 is driven to control the current.
  • FIG. 22 shows a configuration example of the target steering angle generation unit 910.
  • the target steering angle generation unit 910 includes a limiting unit 931, a rate limiting unit 932, and a correction unit 933.
  • the limiting unit 931 limits the upper and lower limits of the steering angle ⁇ h and outputs the steering angle ⁇ h1. Similar to the limiting unit 256 in the SAT information correction unit 250 and the output limiting unit 350 in the torsion angle control unit 300, the upper limit value and the lower limit value for the steering angle ⁇ h are set in advance to limit.
  • the rate limiting unit 932 sets and limits the amount of change in the steering angle ⁇ h1 in order to avoid a sudden change in the steering angle, and outputs the steering angle ⁇ h2. For example, the difference from the steering angle ⁇ h1 one sample before is used as the change amount, and when the absolute value of the change amount is larger than a predetermined value (limit value), the steering angle is set so that the absolute value of the change amount becomes the limit value. ⁇ h1 is added or subtracted and output as the steering angle ⁇ h2, and if it is equal to or less than the limit value, the steering angle ⁇ h1 is output as it is as the steering angle ⁇ h2.
  • an upper limit value and a lower limit value may be set for the amount of change to limit the amount of change. You may want to limit the rate.
  • the correction unit 933 corrects the steering angle ⁇ h2 and outputs the target steering angle ⁇ tref. For example, using a map that defines the characteristics of the target steering angle ⁇ tref with respect to the magnitude
  • FIG. 23 shows a configuration example of the steering angle control unit 920.
  • the steering angle control unit 920 has the same configuration as the configuration example of the torsion angle control unit 300 shown in FIG. 11 excluding the stabilization compensation unit 340 and the addition unit 362, and has a target torsion angle ⁇ ref and a torsion.
  • the target steering angle ⁇ tref and steering angle ⁇ t are input instead of the angle ⁇ , and the steering angle feedback (FB) compensation unit 921, the steering angular velocity calculation unit 922, the speed control unit 923, the output limiting unit 926 and the subtraction unit 927 are input.
  • FB steering angle feedback
  • the same operation is performed with the same configurations as the torsion angle FB compensation unit 310, the torsion angular velocity calculation unit 320, the speed control unit 330, the output limiting unit 350, and the subtraction unit 361, respectively.
  • the angle sensor 73 detects the steering angle ⁇ t
  • the angle sensor 74 detects the motor angle ⁇ m (step S110)
  • the steering angle ⁇ t is the steering angle control unit 920
  • the motor angle ⁇ m is the angular velocity.
  • the angular velocity calculation unit 951 differentiates the motor angle ⁇ m to calculate the motor angular velocity ⁇ m, and outputs the motor angular velocity to the right / left turn determination unit 400 (step S120).
  • the target steering angle generation unit 910 inputs the steering angle ⁇ h, and the steering angle ⁇ h is input to the limiting unit 931.
  • the limiting unit 931 limits the upper and lower limit values of the steering angle ⁇ h by preset upper and lower limit values (step S180), and outputs the steering angle ⁇ h1 to the rate limiting unit 932.
  • the rate limiting unit 932 limits the amount of change in the steering angle ⁇ h1 by a preset limit value (step S190), and outputs the steering angle ⁇ h2 to the correction unit 933.
  • the correction unit 933 corrects the steering angle ⁇ h2 to obtain the target steering angle ⁇ tref (step S200), and outputs the steering angle ⁇ h2 to the steering angle control unit 920.
  • the steering angle control unit 920 which has input the steering angle ⁇ t and the target steering angle ⁇ tref, calculates the deviation ⁇ t 0 by subtracting the steering angle ⁇ t from the target steering angle ⁇ tref by the subtracting unit 927 (step). S210). Deviation Derutashitati 0 is input to the turning angle FB compensation unit 921, the turning angle FB compensation unit 921 compensates the deviation Derutashitati 0 by multiplying the compensation value to the deviation ⁇ t 0 (step S220), the target turning angular velocity The ⁇ tref is output to the speed control unit 923.
  • the steering angular velocity calculation unit 922 inputs the steering angle ⁇ t, calculates the steering angular velocity ⁇ tt by a differential calculation with respect to the steering angle ⁇ t (step S230), and outputs the steering angular velocity ⁇ tt to the speed control unit 923.
  • the speed control unit 923 calculates the motor current command value Imcta by IP control in the same manner as the speed control unit 330 (step S240), and outputs the motor current command value Imcta to the output limiting unit 926.
  • the output limiting unit 926 limits the upper and lower limit values of the motor current command value Imcta by the preset upper limit value and lower limit value (step S250), and outputs the motor current command value Imct as the motor current command value Imct (step S260).
  • the motor current command value Imct is input to the current control unit 930, and the current control unit 930 is based on the motor current command value Imct and the current value Imd of the drive motor 71 detected by the motor current detector 940. 71 is driven and current control is performed (step S270).
  • the speed control unit 923 in the steering angle control unit 920 is not the IP control but the PI control, the P control, the PID control, and the PI-D, like the speed control unit 330 in the twist angle control unit 300. Control and the like are feasible, and any of P, I, and D controls may be used, and follow-up control by the steering angle control unit 920 and the twist angle control unit 300 is generally used.
  • the control structure may be used.
  • one ECU 50 controls the reaction force device 60 and the drive device 70, but the ECU for the reaction force device 60 and the ECU for the drive device 70 are used, respectively. It may be provided. In this case, the ECUs transmit and receive data by communication.
  • the SBW system shown in FIG. 20 does not have a mechanical coupling between the reaction force device 60 and the drive device 70, but when an abnormality occurs in the system, the column shaft 2 and the steering mechanism are clutched or the like.
  • the present invention is also applicable to SBW systems provided with a mechanical torque transmission mechanism that mechanically couples with. In such an SBW system, when the system is normal, the clutch is turned off to open the mechanical torque transmission, and when the system is abnormal, the clutch is turned on to enable the mechanical torque transmission.
  • the twist angle control unit 300 in the first to fourth embodiments and the assist control unit 700 in the third embodiment directly calculate the motor current command value Imc and the assist current command value Iac. Before calculating them, the motor torque (target torque) to be output may be calculated first, and then the motor current command value and the assist current command value may be calculated. In this case, in order to obtain the motor current command value and the assist current command value from the motor torque, the generally used relationship between the motor current and the motor torque is used.

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  • Chemical & Material Sciences (AREA)
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  • Mechanical Engineering (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)
  • Power Steering Mechanism (AREA)

Abstract

[Problem] To provide a vehicle steering device that makes it possible to easily attain a steering torque equivalent to a steering angle or the like independently of the state of a road surface and without being affected by changes in the mechanical characteristics of a steering system resulting from aging. The present invention also addresses the problem of suitably conveying steering reaction force to a driver as a steering sensation when a vehicle is stopped or moving at a very low speed. [Solution] A vehicle steering device that performs assistance control of a steering system, said vehicle steering device being provided with: a target steering torque generation unit for generating a target steering torque; a conversion unit for converting the target steering torque to a target torsion angle; and a torsion angle control unit that calculates a motor current command value whereby the torsion angle is made to follow the target torsion angle. The target steering torque generation unit is equipped with a static steering characteristic correction unit that determines a first torque signal on the basis of desired static steering characteristics corresponding to the steering angle. The first torque signal is output as the target steering torque, and the driving of a motor is controlled on the basis of the motor current command value.

Description

車両用操向装置Steering device for vehicles
本発明は、トーションバー等の捩れ角に基づいて所望の操舵トルクを実現し、路面の状態に影響されず、経年による機構系特性の変化に左右されない高性能な車両用操向装置に関する。 The present invention relates to a high-performance steering device for a vehicle that realizes a desired steering torque based on a torsion angle of a torsion bar or the like, is not affected by a road surface condition, and is not affected by changes in mechanical characteristics over time.
　車両用操向装置の１つである電動パワーステアリング装置（ＥＰＳ）は、車両の操舵系にモータの回転力でアシスト力（操舵補助力）を付与するものであり、インバータから供給される電力で制御されるモータの駆動力を、減速機構を含む伝達機構により、ステアリングシャフト或いはラック軸にアシスト力として付与する。かかる従来の電動パワーステアリング装置は、アシスト力を正確に発生させるため、モータ電流のフィードバック制御を行っている。フィードバック制御は、操舵補助指令値（電流指令値）とモータ電流検出値との差が小さくなるようにモータ印加電圧を調整するものであり、モータ印加電圧の調整は、一般的にＰＷＭ（パルス幅変調）制御のデューティの調整で行っている。 The electric power steering device (EPS), which is one of the steering devices for vehicles, applies an assist force (steering assist force) to the steering system of the vehicle by the rotational force of the motor, and uses the power supplied from the inverter. The driving force of the controlled motor is applied to the steering shaft or rack shaft as an assisting force by a transmission mechanism including a reduction mechanism. In such a conventional electric power steering device, feedback control of the motor current is performed in order to accurately generate an assist force. The feedback control adjusts the motor applied voltage so that the difference between the steering assist command value (current command value) and the motor current detection value becomes small, and the adjustment of the motor applied voltage is generally PWM (pulse width). Modulation) Control duty is adjusted.
　電動パワーステアリング装置の一般的な構成を図１に示して説明すると、ハンドル１のコラム軸（ステアリングシャフト、ハンドル軸）２は減速機構３、ユニバーサルジョイント４ａ及び４ｂ、ピニオンラック機構５、タイロッド６ａ，６ｂを経て、更にハブユニット７ａ，７ｂを介して操向車輪８Ｌ，８Ｒに連結されている。また、トーションバーを有するコラム軸２には、ハンドル１の操舵トルクＴｓを検出するトルクセンサ１０及び操舵角θｈを検出する舵角センサ１４が設けられており、ハンドル１の操舵力を補助するモータ２０が減速機構３を介してコラム軸２に連結されている。電動パワーステアリング装置を制御するコントロールユニット（ＥＣＵ）３０には、バッテリ１３から電力が供給されると共に、イグニションキー１１を経てイグニションキー信号が入力される。コントロールユニット３０は、トルクセンサ１０で検出された操舵トルクＴｓと車速センサ１２で検出された車速Ｖｓとに基づいてアシスト（操舵補助）指令の電流指令値の演算を行い、電流指令値に補償等を施した電圧制御指令値Ｖｒｅｆによって、ＥＰＳ用モータ２０に供給する電流を制御する。 The general configuration of the electric power steering device will be described with reference to FIG. 1. The column shaft (steering shaft, handle shaft) 2 of the handle 1 has a reduction mechanism 3, universal joints 4a and 4b, a pinion rack mechanism 5, and a tie rod 6a. It is further connected to the steering wheels 8L and 8R via the hub units 7a and 7b via 6b. Further, the column shaft 2 having the torsion bar is provided with a torque sensor 10 for detecting the steering torque Ts of the steering wheel 1 and a steering angle sensor 14 for detecting the steering angle θh, and is a motor that assists the steering force of the steering wheel 1. 20 is connected to the column shaft 2 via the reduction mechanism 3. Electric power is supplied from the battery 13 to the control unit (ECU) 30 that controls the electric power steering device, and an ignition key signal is input via the ignition key 11. The control unit 30 calculates the current command value of the assist (steering assistance) command based on the steering torque Ts detected by the torque sensor 10 and the vehicle speed Vs detected by the vehicle speed sensor 12, and compensates the current command value. The current supplied to the EPS motor 20 is controlled by the voltage control command value Vref.
　コントロールユニット３０には、車両の各種情報を授受するＣＡＮ（Controller　Area　Network）４０が接続されており、車速ＶｓはＣＡＮ４０から受信することも可能である。また、コントロールユニット３０には、ＣＡＮ４０以外の通信、アナログ／ディジタル信号、電波等を授受する非ＣＡＮ４１も接続可能である。 A CAN (Controller Area Network) 40 that exchanges various vehicle information is connected to the control unit 30, and the vehicle speed Vs can also be received from the CAN 40. Further, a non-CAN 41 that transmits / receives communications other than CAN 40, analog / digital signals, radio waves, etc. can also be connected to the control unit 30.
　コントロールユニット３０は主としてＣＰＵ（ＭＣＵ、ＭＰＵ等も含む）で構成されるが、そのＣＰＵ内部においてプログラムで実行される一般的な機能を示すと図２のようになる。 The control unit 30 is mainly composed of a CPU (including an MCU, an MPU, etc.), and FIG. 2 shows a general function executed by a program inside the CPU.
　図２を参照してコントロールユニット３０の機能及び動作を説明すると、トルクセンサ１０で検出された操舵トルクＴｓ及び車速センサ１２で検出された（若しくはＣＡＮ４０からの）車速Ｖｓは、電流指令値演算部３１に入力される。電流指令値演算部３１は、入力された操舵トルクＴｓ及び車速Ｖｓに基づいてアシストマップ等を用いて、モータ２０に供給する電流の制御目標値である電流指令値Ｉｒｅｆ１を演算する。電流指令値Ｉｒｅｆ１は加算部３２Ａを経て電流制限部３３に入力され、最大電流を制限された電流指令値Ｉｒｅｆｍが減算部３２Ｂに入力され、フィードバックされているモータ電流値Ｉｍとの偏差Ｉ（＝Ｉｒｅｆｍ－Ｉｍ）が演算され、その偏差Ｉが操舵動作の特性改善のためのＰＩ（比例積分）制御部３５に入力される。ＰＩ制御部３５で特性改善された電圧制御指令値ＶｒｅｆがＰＷＭ制御部３６に入力され、更に駆動部としてのインバータ３７を介してモータ２０がＰＷＭ駆動される。モータ２０の電流値Ｉｍはモータ電流検出器３８で検出され、減算部３２Ｂにフィードバックされる。 Explaining the function and operation of the control unit 30 with reference to FIG. 2, the steering torque Ts detected by the torque sensor 10 and the vehicle speed Vs detected by the vehicle speed sensor 12 (or from the CAN 40) are the current command value calculation unit. It is input to 31. The current command value calculation unit 31 calculates the current command value Iref1, which is the control target value of the current supplied to the motor 20, by using the assist map or the like based on the input steering torque Ts and vehicle speed Vs. The current command value Iref1 is input to the current limiting unit 33 via the adding unit 32A, the current command value Ireffm whose maximum current is limited is input to the subtracting unit 32B, and the deviation I (=) from the fed-back motor current value Im. Irefm-Im) is calculated, and the deviation I is input to the PI (proportional integration) control unit 35 for improving the characteristics of the steering operation. The voltage control command value Vref whose characteristics have been improved by the PI control unit 35 is input to the PWM control unit 36, and the motor 20 is PWM-driven via the inverter 37 as the drive unit. The current value Im of the motor 20 is detected by the motor current detector 38 and fed back to the subtraction unit 32B.
　加算部３２Ａには補償信号生成部３４からの補償信号ＣＭが加算されており、補償信号ＣＭの加算によって操舵システム系の特性補償を行い、収れん性や慣性特性等を改善するようになっている。補償信号生成部３４は、セルフアライニングトルク（ＳＡＴ）３４３と慣性３４２を加算部３４４で加算し、その加算結果に更に収れん性３４１を加算部３４５で加算し、加算部３４５の加算結果を補償信号ＣＭとしている。 The compensation signal CM from the compensation signal generation unit 34 is added to the addition unit 32A, and the characteristics of the steering system system are compensated by adding the compensation signal CM to improve the astringency, inertial characteristics, and the like. .. The compensation signal generation unit 34 adds the self-aligning torque (SAT) 343 and the inertia 342 by the addition unit 344, further adds the convergence 341 to the addition result by the addition unit 345, and compensates the addition result of the addition unit 345. It is a signal CM.
　このように、従来の電動パワーステアリング装置でのアシスト制御では、運転者の手入力にて加えられた操舵トルクをトーションバーの捩れトルクとしてトルクセンサで検出し、主にそのトルクに応じたアシスト電流としてモータ電流を制御している。しかしながら、この方法で制御を行なう場合、路面の状態（例えば傾斜）の違いにより、操舵角によって異なる操舵トルクとなってしまうことがある。モータ出力特性の経年使用によるバラツキによっても、操舵トルクに影響を与えることがある。 In this way, in the assist control of the conventional electric power steering device, the steering torque applied manually by the driver is detected by the torque sensor as the torsion torque of the torsion bar, and the assist current mainly corresponding to the torque is detected. The motor current is controlled as. However, when the control is performed by this method, the steering torque may differ depending on the steering angle due to the difference in the road surface condition (for example, inclination). The steering torque may also be affected by variations in motor output characteristics due to aging.
　かかる問題を解決するために、例えば、特許第５２０８８９４号公報（特許文献１）に示されるような電動パワーステアリング装置が提案されている。特許文献１の電動パワーステアリング装置では、運転者の触覚特性に基づく適切な操舵トルクを与えるために、操舵角又は操舵トルクと手応え量との関係に基づいて決定される操舵角と操舵トルクとの関係（操舵反力特性マップ）に基づいて、操舵トルクの目標値を設定している。 In order to solve such a problem, for example, an electric power steering device as shown in Japanese Patent No. 5208894 (Patent Document 1) has been proposed. In the electric power steering device of Patent Document 1, the steering angle or the steering torque determined based on the relationship between the steering angle or the steering torque and the response amount in order to give an appropriate steering torque based on the tactile characteristics of the driver. The target value of steering torque is set based on the relationship (steering reaction force characteristic map).
特許第５２０８８９４号公報Japanese Patent No. 5208894
　しかしながら、特許文献１の電動パワーステアリング装置では、操舵反力特性マップを予め求めておかなければならず、また、操舵トルクの目標値と検出される操舵トルクとの偏差に基づいて制御を行っているので、操舵トルクに対する影響が残ってしまうおそれがある。 However, in the electric power steering device of Patent Document 1, the steering reaction force characteristic map must be obtained in advance, and control is performed based on the deviation between the target value of the steering torque and the detected steering torque. Therefore, there is a possibility that the influence on the steering torque remains.
　操舵反力に関しては、停車時及び極低速時にも適度な反力を運転者に伝えなければ、抵抗感のない操舵感となり、運転者に違和感を与えるおそれがある。 Regarding the steering reaction force, if the appropriate reaction force is not transmitted to the driver even when the vehicle is stopped and at extremely low speeds, the steering feeling will be felt without resistance, which may give the driver a sense of discomfort.
　本発明は上述のような事情よりなされたものであり、本発明の目的は、路面の状態に影響されず、経年によるステアリング操舵系の機構特性の変化に左右されず、操舵角等に対して同等の操舵トルクを容易に実現することが可能な車両用操向装置を提供することにある。更に、停車時及び極低速時の操舵反力を操舵感として適切に運転者へ伝えることも目的である。 The present invention has been made based on the above circumstances, and an object of the present invention is not affected by the condition of the road surface, not affected by changes in the mechanical characteristics of the steering steering system over time, and with respect to the steering angle and the like. It is an object of the present invention to provide a steering device for a vehicle capable of easily achieving the same steering torque. Further, it is also an object to appropriately convey the steering reaction force at the time of stopping and at extremely low speed to the driver as a steering feeling.
　本発明は、任意のバネ定数を有するトーションバー及び前記トーションバーの捩れ角を検出するセンサを少なくとも備え、モータを駆動制御することにより、操舵系をアシスト制御する車両用操向装置に関し、本発明の上記目的は、目標操舵トルクを生成する目標操舵トルク生成部と、前記目標操舵トルクを目標捩れ角に変換する変換部と、前記目標捩れ角に対して前記捩れ角を追従させるようなモータ電流指令値を演算する捩れ角制御部とを備え、前記目標操舵トルク生成部が、操舵角に応じた所望の据切り特性に基づいて第１トルク信号を求める据切り特性補正部を具備し、前記第１トルク信号を前記目標操舵トルクとして出力し、前記モータ電流指令値に基づいて前記モータを駆動制御することにより達成される。 The present invention relates to a vehicle steering device that includes at least a torsion bar having an arbitrary spring constant and a sensor that detects a torsion angle of the torsion bar, and assists and controls the steering system by driving and controlling a motor. The object of the above is a target steering torque generating unit that generates a target steering torque, a conversion unit that converts the target steering torque into a target torsion angle, and a motor current that causes the torsion angle to follow the target torsion angle. The target steering torque generating unit includes a torsion angle control unit that calculates a command value, and the target steering torque generating unit includes a steering characteristic correction unit that obtains a first torque signal based on a desired steering characteristic according to the steering angle. This is achieved by outputting the first torque signal as the target steering torque and driving and controlling the motor based on the motor current command value.
　また、本発明の上記目的は、前記据切り特性補正部が、操舵状態及び前記操舵角を用いてヒステリシス補正を行って基本トルク信号を求める据切り特性演算部を具備し、前記基本トルク信号を前記第１トルク信号として出力することにより、或いは、前記据切り特性補正部が、前記基本トルク信号に車速感応ゲインを乗算することにより前記第１トルク信号を算出する車速感応ゲイン部を更に具備することにより、或いは、前記車速感応ゲインが、車速が大きくなるに従って小さくなる特性であることにより、或いは、前記目標操舵トルク生成部が、基本マップを用いて前記操舵角及び車速より第２トルク信号を求める基本マップ部と、車速感応であるダンパゲインマップを用いて角速度情報に基づいて第３トルク信号を求めるダンパ演算部とを更に具備し、前記第２トルク信号及び前記第３トルク信号の内の少なくとも１つの信号並びに前記第１トルク信号より前記目標操舵トルクを算出することにより、或いは、前記基本マップが車速感応であることにより、或いは、前記目標操舵トルク生成部が、前記基本マップ部の前段又は後段に、位相補償を行なう位相補償部を更に具備し、前記基本マップ部及び前記位相補償部を介して、前記操舵角及び前記車速より前記第２トルク信号を求めることにより、より効果的に達成される。 Further, the object of the present invention is that the stationary characteristic correction unit includes a stationary characteristic calculation unit that obtains a basic torque signal by performing hysteresis correction using the steering state and the steering angle, and obtains the basic torque signal. The stationary characteristic correction unit further includes a vehicle speed-sensitive gain unit that calculates the first torque signal by outputting it as the first torque signal or by multiplying the basic torque signal by the vehicle speed-sensitive gain. As a result, or because the vehicle speed-sensitive gain has a characteristic that decreases as the vehicle speed increases, or because the target steering torque generator uses a basic map to generate a second torque signal from the steering angle and vehicle speed. A basic map unit to be obtained and a damper calculation unit to obtain a third torque signal based on angular speed information using a damper gain map that is sensitive to vehicle speed are further provided, and the second torque signal and the third torque signal are included. By calculating the target steering torque from at least one signal and the first torque signal, or because the basic map is sensitive to vehicle speed, or because the target steering torque generation unit is in front of the basic map unit. Alternatively, a phase compensation unit that performs phase compensation is further provided in the subsequent stage, and the second torque signal is obtained from the steering angle and the vehicle speed via the basic map unit and the phase compensation unit, so that it is more effective. Achieved.
　本発明の車両用操向装置によれば、目標操舵トルク生成部で生成される目標操舵トルクを基に求められる目標捩れ角に対して制御を行うことにより、目標捩れ角に捩れ角が追従するように動作し、所望の操舵トルクを実現し、運転者の操舵の感覚に基づく適切な操舵トルクを与えることができる。 According to the vehicle steering device of the present invention, the torsion angle follows the target torsion angle by controlling the target torsion angle obtained based on the target steering torque generated by the target steering torque generating unit. It is possible to realize a desired steering torque and to provide an appropriate steering torque based on the driver's steering feeling.
　更に、据切り特性補正部の動作により、停車時及び極低速時の操舵反力を操舵感として適切に運転者へ伝えることができる。 Furthermore, by operating the stationary characteristic correction unit, the steering reaction force at the time of stopping and at extremely low speed can be appropriately transmitted to the driver as a steering feeling.
電動パワーステアリング装置の概要を示す構成図である。It is a block diagram which shows the outline of the electric power steering apparatus. 電動パワーステアリング装置のコントロールユニット（ＥＣＵ）内の構成例を示すブロック図である。It is a block diagram which shows the structural example in the control unit (ECU) of the electric power steering apparatus. ＥＰＳ操舵系と各種センサの設置例を示す構造図である。It is a structural drawing which shows the installation example of an EPS steering system and various sensors. 本発明の構成例（第１実施形態）を示すブロック図である。It is a block diagram which shows the structural example (1st Embodiment) of this invention. 目標操舵トルク生成部の構成例（第１実施形態）を示すブロック図である。It is a block diagram which shows the structural example (first embodiment) of the target steering torque generation part. 基本マップの特性例を示す線図である。It is a diagram which shows the characteristic example of a basic map. ダンパゲインマップの特性例を示す線図である。It is a diagram which shows the characteristic example of a damper gain map. 据切り特性補正部の構成例を示すブロック図である。It is a block diagram which shows the structural example of the stationary characteristic correction part. 据切り特性演算部の特性例を示す線図である。It is a diagram which shows the characteristic example of the stationary characteristic calculation part. 車速感応ゲインの特性例を示す線図である。It is a diagram which shows the characteristic example of the vehicle speed sensitive gain. 捩れ角制御部の構成例を示すブロック図である。It is a block diagram which shows the structural example of the torsion angle control part. 出力制限部での上下限値の設定例を示す線図である。It is a diagram which shows the setting example of the upper and lower limit values in an output limiting part. 本発明の動作例（第１実施形態）を示すフローチャートである。It is a flowchart which shows the operation example (1st Embodiment) of this invention. 目標操舵トルク生成部の動作例（第１実施形態）を示すフローチャートである。It is a flowchart which shows the operation example (1st Embodiment) of the target steering torque generation part. 捩れ角制御部の動作例を示すフローチャートである。It is a flowchart which shows the operation example of the torsion angle control part. 据切り状態での操舵角に対する目標操舵トルクの変化例を示す線図である。It is a diagram which shows the change example of the target steering torque with respect to the steering angle in a stationary state. 目標操舵トルク生成部の構成例（第２実施形態）を示すブロック図である。It is a block diagram which shows the structural example (second embodiment) of the target steering torque generation part. 本発明の構成例（第３実施形態）を示すブロック図である。It is a block diagram which shows the structural example (third embodiment) of this invention. 位相補償部の挿入例を示すブロック図である。It is a block diagram which shows the insertion example of a phase compensation part. ＳＢＷシステムの概要を示す構成図である。It is a block diagram which shows the outline of the SBW system. 本発明の構成例（第４実施形態）を示すブロック図である。It is a block diagram which shows the structural example (fourth embodiment) of this invention. 目標転舵角生成部の構成例を示すブロック図である。It is a block diagram which shows the structural example of the target steering angle generation part. 転舵角制御部の構成例を示すブロック図である。It is a block diagram which shows the structural example of the steering angle control part. 本発明の動作例（第４実施形態）を示すフローチャートである。It is a flowchart which shows the operation example (4th Embodiment) of this invention.
　本発明は、路面の状態に影響されず、操舵角等に対して同等の操舵トルクを実現するための車両用操向装置であり、トーションバー等の捩れ角を、操舵角等に応じた値に追従するように制御することにより所望の操舵トルクを実現している。 The present invention is a vehicle steering device for achieving the same steering torque with respect to the steering angle and the like without being affected by the road surface condition, and the torsion angle of the torsion bar and the like is set to a value according to the steering angle and the like. The desired steering torque is realized by controlling so as to follow.
　以下に、本発明の実施の形態を、図面を参照して説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　先ず、本発明に係る車両用操向装置の１つである電動パワーステアリング装置に関連する情報を検出する各種センサの設置例について説明する。図３は、ＥＰＳ操舵系と各種センサの設置例を示す図であり、コラム軸２にはトーションバー２Ａが備えられている。操向車輪８Ｌ,８Ｒには路面反力Ｆｒ及び路面情報μが作用する。トーションバー２Ａを挟んでコラム軸２のハンドル側には上側角度センサが設けられ、トーションバー２Ａを挟んでコラム軸２の操向車輪側には下側角度センサが設けられており、上側角度センサはハンドル角θ１を検出し、下側角度センサはコラム角θ２を検出する。操舵角θｈはコラム軸２の上部に設けられた舵角センサで検出され、ハンドル角θ１及びコラム角θ２の偏差から、下記数１及び数２によってトーションバーの捩れ角Δθ及びトーションバートルクＴｔを求めることができる。なお、Ｋｔはトーションバー２Ａのバネ定数である。 First, an installation example of various sensors for detecting information related to an electric power steering device, which is one of the steering devices for vehicles according to the present invention, will be described. FIG. 3 is a diagram showing an installation example of the EPS steering system and various sensors, and the column shaft 2 is provided with a torsion bar 2A. The road surface reaction force Fr and the road surface information μ act on the steering wheels 8L and 8R. An upper angle sensor is provided on the handle side of the column shaft 2 with the torsion bar 2A in between, and a lower angle sensor is provided on the steering wheel side of the column shaft 2 with the torsion bar 2A in between. Detects the handle angle θ 1 , and the lower angle sensor detects the column angle θ 2 . The steering angle θh is detected by a steering angle sensor provided on the upper part of the column shaft 2, and from the deviations of the steering wheel angle θ 1 and the column angle θ 2 , the torsion bar torsion angle Δθ and torsion bar torque are determined by the following equations 1 and 2. Tt can be calculated. Kt is the spring constant of the torsion bar 2A.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000002
 　トーションバートルクＴｔは、例えば特開２００８－２１６１７２号公報で示されるトルクセンサを用いて検出することも可能である。なお、本実施形態では、トーションバートルクＴｔを操舵トルクＴｓとしても扱うこととする。
Figure JPOXMLDOC01-appb-M000002
 The torsion bar torque Tt can also be detected using, for example, a torque sensor disclosed in Japanese Patent Application Laid-Open No. 2008-216172. In the present embodiment, the torsion bar torque Tt is also treated as the steering torque Ts.
　次に、本発明の構成例について説明する。 Next, a configuration example of the present invention will be described.
　図４は本発明の構成例（第１実施形態）を示すブロック図であり、運転者のハンドル操舵はＥＰＳ操舵系／車両系１００内のモータでアシスト制御される。目標操舵トルクＴｒｅｆを出力する目標操舵トルク生成部２００には、操舵角θｈの他に、車速Ｖｓ及び右切り／左切り判定部５００から出力される右切り又は左切りの操舵状態ＳＴｓが入力される。目標操舵トルクＴｒｅｆは変換部４００で目標捩れ角Δθｒｅｆに変換され、目標捩れ角Δθｒｅｆは、トーションバー２Ａの捩れ角Δθ及びモータ角速度ωｍと共に捩れ角制御部３００に入力される。捩れ角制御部３００は、捩れ角Δθが目標捩れ角Δθｒｅｆとなるようなモータ電流指令値Ｉｍｃを演算し、モータ電流指令値ＩｍｃによりＥＰＳのモータが駆動される。 FIG. 4 is a block diagram showing a configuration example (first embodiment) of the present invention, in which the driver's steering wheel steering is assist-controlled by a motor in the EPS steering system / vehicle system 100. In addition to the steering angle θh, the vehicle speed Vs and the right-turn or left-turn steering state STs output from the right-turn / left-turn determination unit 500 are input to the target steering torque generation unit 200 that outputs the target steering torque Tref. To torque. The target steering torque Tref is converted into a target torsion angle Δθref by the conversion unit 400, and the target torsion angle Δθref is input to the torsion angle control unit 300 together with the torsion angle Δθ of the torsion bar 2A and the motor angular velocity ωm. The twist angle control unit 300 calculates a motor current command value Imc so that the twist angle Δθ becomes a target twist angle Δθref, and the motor of the EPS is driven by the motor current command value Imcc.
　右切り／左切り判定部５００は、モータ角速度ωｍを基に操舵が右切りか左切りかを判定し、判定結果を操舵状態ＳＴｓとして出力する。即ち、モータ角速度ωｍが正の値の場合は「右切り」と判定し、負の値の場合は「左切り」と判定する。なお、モータ角速度ωｍの代わりに、操舵角θｈ、ハンドル角θ１又はコラム角θ２に対して速度演算を行って算出される角速度を用いても良い。 The right-turn / left-turn determination unit 500 determines whether the steering is right-turn or left-turn based on the motor angular velocity ωm, and outputs the determination result as the steering state STs. That is, when the motor angular velocity ωm is a positive value, it is determined as “right turn”, and when it is a negative value, it is determined as “left turn”. Instead of the motor angular speed .omega.m, the steering angle [theta] h, may be used an angular velocity that is calculated by performing the speed calculation with respect to the handle angle theta 1 or column angle theta 2.
　図５は目標操舵トルク生成部２００の構成例を示しており、目標操舵トルク生成部２００は、基本マップ部２１０、微分部２２０、ダンパゲイン部２３０、据切り特性補正部２４０、乗算部２５０並びに加算部２５１及び２５２を備え、操舵角θｈは基本マップ部２１０、微分部２２０及び据切り特性補正部２４０に入力され、車速Ｖｓは基本マップ部２１０、ダンパゲイン部２３０及び据切り特性補正部２４０に入力され、右切り／左切り判定部５００から出力される操舵状態ＳＴｓは据切り特性補正部２４０に入力される。 FIG. 5 shows a configuration example of the target steering torque generation unit 200, and the target steering torque generation unit 200 includes a basic map unit 210, a differentiation unit 220, a damper gain unit 230, a stationary characteristic correction unit 240, a multiplication unit 250, and an addition unit. The steering angle θh is input to the basic map unit 210, the differential unit 220 and the stationary characteristic correction unit 240, and the vehicle speed Vs is input to the basic map unit 210, the damper gain unit 230 and the stationary characteristic correction unit 240. The steering state STs output from the right-turn / left-turn determination unit 500 are input to the stationary characteristic correction unit 240.
　基本マップ部２１０は、基本マップを有し、基本マップを用いて、図６に示されるような車速Ｖｓをパラメータとするトルク信号（第２トルク信号）Ｔｒｅｆ＿ａを出力する。即ち、トルク信号Ｔｒｅｆ＿ａは、操舵角θｈの大きさ（絶対値）｜θｈ｜が増加するにつれて増加し、車速Ｖｓが０［ｋｍ／ｈ］から増加するにつれても増加するようになっている。符号部２１１は操舵角θｈの符号（＋１又は－１）を乗算部２１２に出力する。操舵角θｈの大きさからマップによりトルク信号Ｔｒｅｆ＿ａの大きさを求め、これに操舵角θｈの符号を乗算し、トルク信号Ｔｒｅｆ＿ａを演算する。なお、図６では操舵角θｈの大きさ｜θｈ｜を参照するマップ、符号部及び乗算部で基本マップ部２１０を構成しているが、正負の操舵角θｈに応じてマップを構成しても良く、この場合、操舵角θｈが正の場合と負の場合とで変化の態様を変えても良い。また、図６に示される基本マップは車速感応であるが、車速感応でなくても良い。 The basic map unit 210 has a basic map, and uses the basic map to output a torque signal (second torque signal) Tref_a having the vehicle speed Vs as a parameter as shown in FIG. That is, the torque signal Tref_a increases as the magnitude (absolute value) | θh | of the steering angle θh increases, and increases as the vehicle speed Vs increases from 0 [km / h]. The code unit 211 outputs the code (+1 or -1) of the steering angle θh to the multiplication unit 212. The magnitude of the torque signal Tref_a is obtained from the magnitude of the steering angle θh by a map, and this is multiplied by the sign of the steering angle θh to calculate the torque signal Tref_a. In FIG. 6, the basic map unit 210 is composed of the map, the sign unit, and the multiplication unit that refer to the magnitude | θh | of the steering angle θh, but the map may be configured according to the positive and negative steering angles θh. In this case, the mode of change may be changed depending on whether the steering angle θh is positive or negative. Further, although the basic map shown in FIG. 6 is vehicle speed sensitive, it does not have to be vehicle speed sensitive.
　微分部２２０は、操舵角θｈを微分して角速度情報である舵角速度ωｈを算出し、舵角速度ωｈは乗算部２５０に入力される。 The differentiation unit 220 differentiates the steering angle θh to calculate the steering angle velocity ωh, which is the angular velocity information, and the steering angle velocity ωh is input to the multiplication unit 250.
　ダンパゲイン部２３０は、舵角速度ωｈに乗算されるダンパゲインＤＧを出力する。乗算部２５０にてダンパゲインＤＧを乗算された舵角速度ωｈは、トルク信号（第３トルク信号）Ｔｒｅｆ＿ｂとして加算部２５２に入力される。ダンパゲインＤＧは、ダンパゲイン部２３０が有する車速感応型のダンパゲインマップを用いて、車速Ｖｓに応じて求められる。ダンパゲインマップは、例えば、図７に示されるように、車速Ｖｓが高くなるに従って徐々に大きくなる特性を有する。ダンパゲインマップは操舵角θｈに応じて可変としても良い。なお、ダンパゲイン部２３０及び乗算部２５０でダンパ演算部を構成している。 Damper gain unit 230 outputs the damper gain D G is multiplied by the steering angular speed [omega] h. Steering angular velocity ωh, which is multiplied by the damper gain D G at multiplying unit 250 is input to the adder 252 as the torque signal (third torque signal) Tref_b. Damper gain D G, using the damper gain map of vehicle speed sensitive type having the damper gain unit 230 is determined according to the vehicle speed Vs. The damper gain map has a characteristic that it gradually increases as the vehicle speed Vs increases, as shown in FIG. 7, for example. The damper gain map may be variable according to the steering angle θh. The damper gain unit 230 and the multiplication unit 250 constitute a damper calculation unit.
　据切り特性補正部２４０は、車両の停車時にハンドルを操舵する据切り状態及び極低速時でのハンドル操舵における操舵角θｈに応じた操舵トルクの特性（据切り特性）を所望の特性とするトルク信号（第１トルク信号）Ｔｒｅｆ＿ｃを出力する。図８に据切り特性補正部２４０の構成例を示す。据切り特性補正部２４０は据切り特性演算部２４１及び車速感応ゲイン部２４２を備える。 The stationary characteristic correction unit 240 has a torque that makes the steering torque characteristic (stationary characteristic) desired according to the steering angle θh in the stationary state in which the steering wheel is steered when the vehicle is stopped and in the steering at extremely low speed. The signal (first torque signal) Tref_c is output. FIG. 8 shows a configuration example of the stationary characteristic correction unit 240. The stationary characteristic correction unit 240 includes a stationary characteristic calculation unit 241 and a vehicle speed sensitive gain unit 242.
　据切り特性演算部２４１は、据切り特性をヒステリシス特性とするために、操舵角θｈ及び操舵状態ＳＴｓに基づき、下記数３に従ってトルク信号（基本トルク信号）Ｔｒｅｆ＿ｓを演算する。なお、下記数３では、ｘ＝θｈ、ｙ＝Ｔｒｅｆ＿ｓとしており、ａ＞１、ｃ＞０であり、Ａｈｙｓはヒステリシス幅である。 The stationary characteristic calculation unit 241 calculates the torque signal (basic torque signal) Tref_s according to the following equation 3 based on the steering angle θh and the steering state STs in order to make the stationary characteristic a hysteresis characteristic. In the following equation 3, x = θh, y = Tref_s, a> 1, c> 0, and A hys is the hysteresis width.
Figure JPOXMLDOC01-appb-M000003
 　右切り操舵から左切り操舵、左切り操舵から右切り操舵へ切り替える際に、最終座標（ｘ１，ｙ１）の値に基づき、切り替え後の数３の“ｂ”に以下の数４を代入する。これにより、切り替え前後の連続性が保たれる。
Figure JPOXMLDOC01-appb-M000003
 When switching from right-turn steering to left-turn steering and from left-turn steering to right-turn steering, the following equation 4 is substituted for "b" of equation 3 after switching based on the values of the final coordinates (x1, y1). As a result, continuity before and after switching is maintained.
Figure JPOXMLDOC01-appb-M000004
 上記数４は、上記数３中のｘにｘ１を、ｙＲ及びｙＬにｙ１を代入することにより導出することができる。
Figure JPOXMLDOC01-appb-M000004
 The above number 4 can be derived by substituting x1 for x and y1 for y R and y L in the above number 3.
　“ａ”として１より大きい任意の正数を用いることができ、例えば、ネイピア数“ｅ”を用いた場合、数３及び数４は下記数５及び数６となる。 Any positive number larger than 1 can be used as "a". For example, when the Napier number "e" is used, the numbers 3 and 4 become the following numbers 5 and 6.
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000006
 　数５及び数６においてＡｈｙｓ＝１［Ｎｍ］、ｃ＝０．３と設定し、０［ｄｅｇ］から開始し、＋５０［ｄｅｇ］、－５０［ｄｅｇ］の操舵をした場合の、ヒステリシス補正されたトルク信号Ｔｒｅｆ＿ｓの線図例を図９に示す。即ち、据切り特性演算部２４１からのトルク信号Ｔｒｅｆ＿ｓは、０の原点→Ｌ１（細線）→Ｌ２（破線）→Ｌ３（太線）のようなヒステリシス特性である。
Figure JPOXMLDOC01-appb-M000006
 Hysteresis correction when A hys = 1 [Nm] and c = 0.3 are set in Equations 5 and 6 and the steering is started from 0 [deg] and steered at +50 [deg] and -50 [deg]. FIG. 9 shows an example of a diagram of the torque signal Tref_s. That is, the torque signal Tref_s from the stationary characteristic calculation unit 241 has a hysteresis characteristic such as the origin of 0 → L1 (thin line) → L2 (broken line) → L3 (thick line).
　なお、ヒステリシス特性の出力幅を表す係数であるＡｈｙｓ及び丸みを表す係数であるｃを操舵角θｈに応じて可変としても良い。 A hys, which is a coefficient representing the output width of the hysteresis characteristic, and c, which is a coefficient representing roundness, may be made variable according to the steering angle θh.
　車速感応ゲイン部２４２は、車速に応じたゲイン（車速感応ゲイン）をトルク信号Ｔｒｅｆ＿ｓに乗算することにより、トルク信号Ｔｒｅｆ＿ｃを出力する。車速感応ゲインは、車速Ｖｓが大きくなるに従って小さくなるように設定される。例えば、図１０に示されるように、車速Ｖｓが０ｋｍ／ｈの時（停車時）にトルク信号Ｔｒｅｆ＿ｓの大きさが２［Ｎｍ］となるように車速感応ゲインを２．０とし、その後、車速Ｖｓが大きくなるに従って、一定の割合で車速感応ゲインは小さくなり、車速ＶｓがＶｓ１（例えば２ｋｍ／ｈ）になったら、減少する割合を小さくし、車速ＶｓがＶｓ２（例えば６ｋｍ／ｈ）の時に車速感応ゲインは０となるようにする。なお、車速Ｖｓが０ｋｍ／ｈの時の車速感応ゲインの値は２．０以外でも良く、車速感応ゲインが減少する割合が変わる箇所は複数でも良く、車速感応ゲインの変化は直線的な変化ではなく、曲線的な変化でも良い。 The vehicle speed-sensitive gain unit 242 outputs the torque signal Tref_c by multiplying the torque signal Tref_s by the gain corresponding to the vehicle speed (vehicle speed-sensitive gain). The vehicle speed sensitive gain is set so as to decrease as the vehicle speed Vs increases. For example, as shown in FIG. 10, when the vehicle speed Vs is 0 km / h (when the vehicle is stopped), the vehicle speed sensitive gain is set to 2.0 so that the magnitude of the torque signal Tref_s is 2 [Nm], and then the vehicle speed. As the Vs increases, the vehicle speed sensitive gain decreases at a constant rate, and when the vehicle speed Vs reaches Vs1 (for example, 2 km / h), the decrease rate decreases, and when the vehicle speed Vs is Vs2 (for example, 6 km / h). The vehicle speed sensitive gain is set to 0. The value of the vehicle speed-sensitive gain when the vehicle speed Vs is 0 km / h may be other than 2.0, the rate at which the vehicle speed-sensitive gain decreases may change at multiple locations, and the change in vehicle speed-sensitive gain may be a linear change. It may be a curvilinear change.
　このように、据切り特性演算部２４１により据切り特性にヒステリシス性を持たせ、車速感応ゲイン部２４２により据切り特性を車速感応とすることによって、据切り特性を所望の特性とするトルク信号Ｔｒｅｆ＿ｃを生成し、トルク信号Ｔｒｅｆ＿ｃにより、停車時及び極低速時の操舵反力を操舵感として適切に運転者へ伝えることが可能となる。なお、車速感応ゲイン部２４２の代わりに、ヒステリシス幅Ａｈｙｓを車速Ｖｓに応じて可変とすることにより、据切り特性を車速感応としても良い。この場合、車速感応ゲイン部２４２は不要となる。係数ａも車速Ｖｓに応じて可変としても良い。また、所望に応じて、据切り特性をヒステリシス特性以外の特性としても良い。 In this way, the stationary characteristic calculation unit 241 gives the stationary characteristic a hysteresis property, and the vehicle speed sensitive gain unit 242 makes the stationary characteristic vehicle speed sensitive, so that the torque signal Tref_c makes the stationary characteristic a desired characteristic. Is generated, and the torque signal Tref_c makes it possible to appropriately transmit the steering reaction force at the time of stopping and at extremely low speed to the driver as a steering feeling. Instead of the vehicle speed sensitive gain unit 242, by varying the hysteresis width A hys according to the vehicle speed Vs, may be vehicle speed sensitive to据切Ri characteristics. In this case, the vehicle speed-sensitive gain unit 242 becomes unnecessary. The coefficient a may also be variable according to the vehicle speed Vs. Further, if desired, the stationary characteristic may be a characteristic other than the hysteresis characteristic.
　トルク信号Ｔｒｅｆ＿ｃ、Ｔｒｅｆ＿ｂ及びＴｒｅｆ＿ａは、加算部２５２及び２５１で順次加算され、目標操舵トルクＴｒｅｆとして出力される。 The torque signals Tref_c, Tref_b and Tref_a are sequentially added by the addition units 252 and 251 and output as the target steering torque Tref.
　なお、舵角速度ωｈは、操舵角θｈに対する微分演算により求めているが、高域のノイズの影響を低減するために適度にローパスフィルタ（ＬＰＦ）処理を実施している。また、ハイパスフィルタ（ＨＰＦ）とゲインにより、微分演算とＬＰＦの処理を実施しても良い。更に、舵角速度ωｈは、操舵角θｈではなく、上側角度センサが検出するハンドル角θ１又は下側角度センサが検出するコラム角θ２に対して微分演算とＬＰＦの処理を行って算出しても良い。舵角速度ωｈの代わりにモータ角速度ωｍを角速度情報として使用しても良く、この場合、微分部２２０は不要となる。 The rudder angular velocity ωh is obtained by a differential calculation with respect to the steering angle θh, but a low-pass filter (LPF) process is appropriately performed in order to reduce the influence of high-frequency noise. Further, the differential operation and the LPF processing may be performed by the high-pass filter (HPF) and the gain. Further, the steering angular velocity ωh is calculated by performing differential calculation and LPF processing on the handle angle θ 1 detected by the upper angle sensor or the column angle θ 2 detected by the lower angle sensor instead of the steering angle θh. Is also good. The motor angular velocity ωm may be used as the angular velocity information instead of the steering angular velocity ωh, and in this case, the differential unit 220 becomes unnecessary.
　変換部４００は、トーションバー２Ａのバネ定数Ｋｔの逆数の符号を反転した－１／Ｋｔの特性を有しており、目標操舵トルクＴｒｅｆを目標捩れ角Δθｒｅｆに変換する。 The conversion unit 400 has a characteristic of -1 / Kt in which the sign of the reciprocal of the spring constant Kt of the torsion bar 2A is inverted, and converts the target steering torque Tref into the target torsion angle Δθref.
　捩れ角制御部３００は、目標捩れ角Δθｒｅｆ、捩れ角Δθ及びモータ角速度ωｍに基づいてモータ電流指令値Ｉｍｃを演算する。図１１は捩れ角制御部３００の構成例を示すブロック図であり、捩れ角制御部３００は、捩れ角フィードバック（ＦＢ）補償部３１０、捩れ角速度演算部３２０、速度制御部３３０、安定化補償部３４０、出力制限部３５０、減算部３６１及び加算部３６２を備えており、変換部４００から出力される目標捩れ角Δθｒｅｆは減算部３６１に加算入力され、捩れ角Δθは減算部３６１に減算入力されると共に、捩れ角速度演算部３２０に入力され、モータ角速度ωｍは安定化補償部３４０に入力される。 The twist angle control unit 300 calculates the motor current command value Imc based on the target twist angle Δθref, the twist angle Δθ, and the motor angular velocity ωm. FIG. 11 is a block diagram showing a configuration example of the torsion angle control unit 300, wherein the torsion angle control unit 300 includes a torsion angle feedback (FB) compensation unit 310, a torsion angular velocity calculation unit 320, a speed control unit 330, and a stabilization compensation unit. It includes 340, an output limiting unit 350, a subtracting unit 361, and an adding unit 362. The target torsional angle Δθref output from the conversion unit 400 is additionally input to the subtracting unit 361, and the twisting angle Δθ is subtracted and input to the subtracting unit 361. At the same time, it is input to the torsion angular velocity calculation unit 320, and the motor angular velocity ωm is input to the stabilization compensation unit 340.
　捩れ角ＦＢ補償部３１０は、減算部３６１で算出される目標捩れ角Δθｒｅｆと捩れ角Δθの偏差Δθ０に対して補償値ＣＦＢ（伝達関数）を乗算し、目標捩れ角Δθｒｅｆに捩れ角Δθが追従するような目標捩れ角速度ωｒｅｆを出力する。補償値ＣＦＢは単純なゲインＫｐｐでも、ＰＩ制御の補償値など一般的に用いられている補償値でも良い。目標捩れ角速度ωｒｅｆは速度制御部３３０に入力される。捩れ角ＦＢ補償部３１０と速度制御部３３０により、目標捩れ角Δθｒｅｆに捩れ角Δθを追従させ、所望の操舵トルクを実現することが可能となる。 The twist angle FB compensation unit 310 multiplies the compensation value C FB (transfer function) by the deviation Δθ 0 of the target twist angle Δθref calculated by the subtraction unit 361 and the twist angle Δθ, and the twist angle Δθref is multiplied by the target twist angle Δθref. Outputs the target torsional velocity ωref that follows. The compensation value C FB may be a simple gain Kpp or a commonly used compensation value such as a PI control compensation value. The target torsional velocity ωref is input to the speed control unit 330. The twist angle FB compensation unit 310 and the speed control unit 330 make it possible to make the twist angle Δθ follow the target twist angle Δθref and realize a desired steering torque.
　捩れ角速度演算部３２０は、捩れ角Δθに対する微分演算により捩れ角速度ωｔを算出し、捩れ角速度ωｔは速度制御部３３０に入力される。微分演算として、ＨＰＦとゲインによる擬似微分を行なっても良い。また、捩れ角速度ωｔを別の手段や捩れ角Δθ以外から算出し、速度制御部３３０に入力するようにしても良い。 The torsion angular velocity calculation unit 320 calculates the torsion angular velocity ωt by a differential calculation with respect to the torsion angle Δθ, and the torsion angular velocity ωt is input to the speed control unit 330. As a differential operation, pseudo-differentiation by HPF and gain may be performed. Further, the torsion angular velocity ωt may be calculated from another means or other than the torsion angle Δθ and input to the velocity control unit 330.
　速度制御部３３０は、Ｉ－Ｐ制御（比例先行型ＰＩ制御）により、目標捩れ角速度ωｒｅｆに捩れ角速度ωｔが追従するようなモータ電流指令値Ｉｍｃａ１を算出する。減算部３３３で目標捩れ角速度ωｒｅｆと捩れ角速度ωｔとの差分（ωｒｅｆ－ωｔ）を算出し、その差分を、ゲインＫｖｉを有する積分部３３１にて積分し、積分結果は減算部３３４に加算入力される。捩れ角速度ωｔは比例部３３２にも入力され、ゲインＫｖｐによる比例処理を施され、減算部３３４に減算入力される。減算部３３４での減算結果がモータ電流指令値Ｉｍｃａ１として出力される。なお、速度制御部３３０は、Ｉ－Ｐ制御ではなく、ＰＩ制御、Ｐ（比例）制御、ＰＩＤ（比例積分微分）制御、ＰＩ－Ｄ制御（微分先行型ＰＩＤ制御）、モデルマッチング制御、モデル規範制御等の一般的に用いられている制御方法でモータ電流指令値Ｉｍｃａ１を算出しても良い。 The speed control unit 330 calculates the motor current command value Imca1 so that the torsion angular velocity ωt follows the target torsional velocity ωref by IP control (proportional leading PI control). The subtraction unit 333 calculates the difference (ωref-ωt) between the target torsional velocity ωref and the torsional angular velocity ωt, integrates the difference with the integration unit 331 having the gain Kvi, and the integration result is additionally input to the subtraction unit 334. To. The torsion angular velocity ωt is also input to the proportional unit 332, is subjected to proportional processing by the gain Kvp, and is subtracted and input to the subtraction unit 334. The subtraction result in the subtraction unit 334 is output as the motor current command value Imca1. The speed control unit 330 is not an IP control, but a PI control, a P (proportional) control, a PID (proportional integral differential) control, a PI-D control (differential leading PID control), a model matching control, and a model reference. The motor current command value Imca1 may be calculated by a commonly used control method such as control.
　安定化補償部３４０は補償値Ｃｓ（伝達関数）を有しており、モータ角速度ωｍよりモータ電流指令値Ｉｍｃａ２を算出する。追従性及び外乱特性を向上させるために、捩れ角ＦＢ補償部３１０及び速度制御部３３０のゲインを上げると、高域の制御的な発振現象が発生してしまう。この対策として、モータ角速度ωｍに対し、安定化するために必要な伝達関数（Ｃｓ）を安定化補償部３４０に設定する。これにより、ＥＰＳ制御システム全体の安定化を実現することができる。安定化補償部３４０の伝達関数（Ｃｓ）として、例えば１次のＨＰＦの構造を用いた擬似微分とゲインにより設定した、下記数７で表わされる１次フィルタを使用する。 The stabilization compensation unit 340 has a compensation value Cs (transfer function), and calculates the motor current command value Imca2 from the motor angular velocity ωm. If the gains of the torsion angle FB compensating unit 310 and the speed control unit 330 are increased in order to improve the followability and the disturbance characteristics, a high-frequency controlled oscillation phenomenon occurs. As a countermeasure, the transfer function (Cs) required for stabilizing the motor angular velocity ωm is set in the stabilization compensation unit 340. As a result, it is possible to realize stabilization of the entire EPS control system. As the transfer function (Cs) of the stabilization compensation unit 340, for example, a first-order filter represented by the following equation 7 set by pseudo differentiation and gain using the structure of the first-order HPF is used.
Figure JPOXMLDOC01-appb-M000007
 ここで、Ｋｓｔａはゲインで、ｆｃは遮断周波数であり、ｆｃとして例えば１５０［Ｈｚ］を設定する。ｓはラプラス演算子である。なお、伝達関数として、２次フィルタ、４次フィルタ等を使用しても良い。
Figure JPOXMLDOC01-appb-M000007
 Here, K sta is a gain, fc is a cutoff frequency, and for example, 150 [Hz] is set as fc. s is the Laplace operator. A second-order filter, a fourth-order filter, or the like may be used as the transfer function.
　速度制御部３３０からのモータ電流指令値Ｉｍｃａ１及び安定化補償部３４０からのモータ電流指令値Ｉｍｃａ２は加算部３６２で加算され、モータ電流指令値Ｉｍｃｂとして出力される。 The motor current command value Imca1 from the speed control unit 330 and the motor current command value Imca2 from the stabilization compensation unit 340 are added by the addition unit 362 and output as the motor current command value Imccb.
　出力制限部３５０は、モータ電流指令値Ｉｍｃｂの上下限値を制限して、モータ電流指令値Ｉｍｃを出力する。図１２に示されるように、モータ電流指令値に対する上限値及び下限値を予め設定し、入力するモータ電流指令値Ｉｍｃｂが、上限値以上の場合は上限値を、下限値以下の場合は下限値を、それ以外の場合はモータ電流指令値Ｉｍｃｂを、モータ電流指令値Ｉｍｃとして出力する。 The output limiting unit 350 limits the upper and lower limits of the motor current command value Imccb and outputs the motor current command value Imcc. As shown in FIG. 12, the upper limit value and the lower limit value with respect to the motor current command value are set in advance, and when the input motor current command value Imccb is equal to or more than the upper limit value, the upper limit value is set, and when it is less than the lower limit value, the lower limit value In other cases, the motor current command value Imccb is output as the motor current command value Imcc.
　このような構成において、本実施形態の動作例を図１３～図１５のフローチャートを参照して説明する。 In such a configuration, an operation example of this embodiment will be described with reference to the flowcharts of FIGS. 13 to 15.
　動作を開始すると、右切り／左切り判定部５００は、モータ角速度ωｍを入力し、モータ角速度ωｍの符号を基に操舵が右切りか左切りかを判定し、判定結果を操舵状態ＳＴｓとして、目標操舵トルク生成部２００に出力する（ステップＳ１０）。 When the operation is started, the right-turn / left-turn determination unit 500 inputs the motor angular velocity ωm, determines whether the steering is right-turn or left-turn based on the sign of the motor angular velocity ωm, and sets the determination result as the steering state STs. Output to the target steering torque generation unit 200 (step S10).
　目標操舵トルク生成部２００は、操舵状態ＳＴｓと共に、操舵角θｈ及び車速Ｖｓを入力し、目標操舵トルクＴｒｅｆを生成する（ステップＳ２０）。目標操舵トルク生成部２００の動作例については、図１４のフローチャートを参照して説明する。 The target steering torque generation unit 200 inputs the steering angle θh and the vehicle speed Vs together with the steering state STs, and generates the target steering torque Tref (step S20). An operation example of the target steering torque generation unit 200 will be described with reference to the flowchart of FIG.
　目標操舵トルク生成部２００に入力された操舵角θｈは基本マップ部２１０、微分部２２０及び据切り特性補正部２４０に、操舵状態ＳＴｓは据切り特性補正部２４０に、車速Ｖｓは基本マップ部２１０、ダンパゲイン部２３０及び据切り特性補正部２４０にそれぞれ入力される（ステップＳ２１）。 The steering angle θh input to the target steering torque generation unit 200 is in the basic map unit 210, the differential unit 220 and the stationary characteristic correction unit 240, the steering state STs is in the stationary characteristic correction unit 240, and the vehicle speed Vs is in the basic map unit 210. , Are input to the damper gain unit 230 and the stationary characteristic correction unit 240, respectively (step S21).
　基本マップ部２１０は、図６に示される基本マップを用いて、操舵角θｈ及び車速Ｖｓに応じたトルク信号Ｔｒｅｆ＿ａを生成して、加算部２５１に出力する（ステップＳ２２）。 The basic map unit 210 generates a torque signal Tref_a corresponding to the steering angle θh and the vehicle speed Vs using the basic map shown in FIG. 6 and outputs the torque signal to the addition unit 251 (step S22).
　微分部２２０は操舵角θｈを微分して舵角速度ωｈを出力し（ステップＳ２３）、ダンパゲイン部２３０は図７に示されるダンパゲインマップを用いて車速Ｖｓに応じたダンパゲインＤＧを出力し（ステップＳ２４）、乗算部２５０は舵角速度ωｈ及びダンパゲインＤＧを乗算してトルク信号Ｔｒｅｆ＿ｂを演算し、加算部２５２に出力する（ステップＳ２５）。 Differentiating section 220 differentiates the steering angle θh outputs steering angular velocity [omega] h (step S23), damper gain unit 230 outputs the damper gain D G corresponding to the vehicle speed Vs by using the damper gain map shown in FIG 7 (step S24), the multiplication unit 250 calculates a torque signal Tref_b by multiplying the steering angular velocity ωh and damper gain D G, and outputs the result to adding section 252 (step S25).
　据切り特性補正部２４０では、操舵角θｈ及び操舵状態ＳＴｓは据切り特性演算部２４１に、車速Ｖｓは車速感応ゲイン部２４２にそれぞれ入力される。据切り特性演算部２４１は、操舵角θｈに対して、操舵状態ＳＴｓに応じて数５及び数６による演算を切り替えてヒステリシス補正を実施し（ステップＳ２６）、トルク信号Ｔｒｅｆ＿ｓを生成し、車速感応ゲイン部２４２に出力する。車速感応ゲイン部２４２は、車速Ｖｓに応じて、図１０に示される特性により車速感応ゲインを決定し、トルク信号Ｔｒｅｆ＿ｓに乗算し、トルク信号Ｔｒｅｆ＿ｃとして加算部２５２に出力する（ステップＳ２７）。なお、据切り特性演算部２４１には、数５及び数６におけるヒステリシス幅Ａｈｙｓ、ｃ、ｘ１及びｙ１が予め設定し保持されているが、数６よりｂ及びｂ’を予め算出し、ｘ１及びｙ１の代わりにｂ及びｂ’を保持するようにしても良い。 In the stationary characteristic correction unit 240, the steering angle θh and the steering state STs are input to the stationary characteristic calculation unit 241 and the vehicle speed Vs is input to the vehicle speed sensitive gain unit 242. The stationary characteristic calculation unit 241 performs hysteresis correction for the steering angle θh by switching the calculation according to the equation 5 and the equation 6 according to the steering state STs (step S26), generates the torque signal Tref_s, and responds to the vehicle speed. Output to the gain unit 242. The vehicle speed-sensitive gain unit 242 determines the vehicle speed-sensitive gain according to the characteristics shown in FIG. 10 according to the vehicle speed Vs, multiplies the torque signal Tref_s, and outputs the torque signal Tref_c to the addition unit 252 (step S27). The stationary characteristic calculation unit 241 presets and holds the hysteresis widths A hys , c, x1 and y1 in the equations 5 and 6, but b and b'are calculated in advance from the equation 6 and x1. And b and b'may be retained instead of y1.
　そして、加算部２５２にてトルク信号Ｔｒｅｆ＿ｂ及びＴｒｅｆ＿ｃが加算され、その加算結果にトルク信号Ｔｒｅｆ＿ａが加算部２５１にて加算され、目標操舵トルクＴｒｅｆが演算される（ステップＳ２８）。 Then, the torque signals Tref_b and Tref_c are added by the addition unit 252, the torque signal Tref_a is added by the addition unit 251 to the addition result, and the target steering torque Tref is calculated (step S28).
　目標操舵トルク生成部２００で生成された目標操舵トルクＴｒｅｆは変換部４００に入力され、変換部４００で目標捩れ角Δθｒｅｆに変換される（ステップＳ３０）。目標捩れ角Δθｒｅｆは捩れ角制御部３００に入力される。 The target steering torque Tref generated by the target steering torque generation unit 200 is input to the conversion unit 400, and is converted into the target twist angle Δθref by the conversion unit 400 (step S30). The target twist angle Δθref is input to the twist angle control unit 300.
　捩れ角制御部３００は、目標捩れ角Δθｒｅｆと共に、捩れ角Δθ及びモータ角速度ωｍを入力し、モータ電流指令値Ｉｍｃを演算する（ステップＳ４０）。捩れ角制御部３００の動作例については、図１５のフローチャートを参照して説明する。 The twist angle control unit 300 inputs the twist angle Δθ and the motor angular velocity ωm together with the target twist angle Δθref, and calculates the motor current command value Imc (step S40). An operation example of the twist angle control unit 300 will be described with reference to the flowchart of FIG.
　捩れ角制御部３００に入力された目標捩れ角Δθｒｅｆは減算部３６１に、捩れ角Δθは減算部３６１及び捩れ角速度演算部３２０に、モータ角速度ωｍは安定化補償部３４０にそれぞれ入力される（ステップＳ４１）。 The target torsion angle Δθref input to the torsion angle control unit 300 is input to the subtraction unit 361, the torsion angle Δθ is input to the subtraction unit 361 and the torsional velocity calculation unit 320, and the motor angular velocity ωm is input to the stabilization compensation unit 340 (step). S41).
　減算部３６１では、目標捩れ角Δθｒｅｆから捩れ角Δθを減算することにより、偏差Δθ０が算出される（ステップＳ４２）。偏差Δθ０は捩れ角ＦＢ補償部３１０に入力され、捩れ角ＦＢ補償部３１０は、偏差Δθ０に補償値ＣＦＢを乗算することにより偏差Δθ０を補償し（ステップＳ４３）、目標捩れ角速度ωｒｅｆを速度制御部３３０に出力する。 In the subtraction unit 361, the deviation Δθ 0 is calculated by subtracting the twist angle Δθ from the target twist angle Δθref (step S42). Deviation [Delta] [theta] 0 is input to the helix angle FB compensation unit 310, the twist angle FB compensation unit 310 compensates the deviation [Delta] [theta] 0 is multiplied by the compensation value C FB on the deviation [Delta] [theta] 0 (step S43), the target torsion angular velocity ωref Is output to the speed control unit 330.
　捩れ角Δθを入力した捩れ角速度演算部３２０は、捩れ角Δθに対する微分演算により捩れ角速度ωｔを算出し（ステップＳ４４）、速度制御部３３０に出力する。 The torsion angular velocity calculation unit 320 that has input the torsion angle Δθ calculates the torsion angular velocity ωt by a differential calculation with respect to the torsion angle Δθ (step S44), and outputs the torsion angular velocity ωt to the speed control unit 330.
　速度制御部３３０では、目標捩れ角速度ωｒｅｆと捩れ角速度ωｔの差分が減算部３３３で算出され、その差分が積分部３３１で積分（Ｋｖｉ／ｓ）されて減算部３３４に加算入力される（ステップＳ４５）。更に、捩れ角速度ωｔは比例部３３２で比例処理（Ｋｖｐ）され、比例結果が減算部３３４に減算入力され（ステップＳ４５）、減算部３３４の減算結果であるモータ電流指令値Ｉｍｃａ１が出力され、加算部３６２に入力される。 In the speed control unit 330, the difference between the target torsional velocity ωref and the torsional angular velocity ωt is calculated by the subtraction unit 333, and the difference is integrated (Kvi / s) by the integration unit 331 and additionally input to the subtraction unit 334 (step S45). ). Further, the torsion angular velocity ωt is proportionally processed (Kvp) by the proportional unit 332, the proportional result is subtracted and input to the subtraction unit 334 (step S45), and the motor current command value Imca1 which is the subtraction result of the subtraction unit 334 is output and added. It is input to the unit 362.
　安定化補償部３４０は、入力したモータ角速度ωｍに対して、数７で表される伝達関数Ｃｓを用いて安定化補償を行い（ステップＳ４６）、安定化補償部３４０からのモータ電流指令値Ｉｍｃａ２は加算部３６２に入力される。 The stabilization compensation unit 340 performs stabilization compensation on the input motor angular velocity ωm using the transfer function Cs represented by Equation 7 (step S46), and the motor current command value Imca2 from the stabilization compensation unit 340. Is input to the addition unit 362.
　加算部３６２ではモータ電流指令値Ｉｍｃａ１及びＩｍｃａ２の加算が行われ（ステップＳ４７）、加算結果であるモータ電流指令値Ｉｍｃｂは出力制限部３５０に入力される。出力制限部３５０は、予め設定された上限値及び下限値によりモータ電流指令値Ｉｍｃｂの上下限値を制限し（ステップＳ４８）、モータ電流指令値Ｉｍｃとして出力する（ステップＳ４９）。 The addition unit 362 adds the motor current command values Imca1 and Imca2 (step S47), and the motor current command value Imccb, which is the addition result, is input to the output limiting unit 350. The output limiting unit 350 limits the upper and lower limit values of the motor current command value Imccb by the preset upper limit value and lower limit value (step S48), and outputs the motor current command value Imcc (step S49).
　捩れ角制御部３００から出力されたモータ電流指令値Ｉｍｃに基づいてモータを駆動し、電流制御が実施される（ステップＳ５０）。 The motor is driven based on the motor current command value Imcc output from the torsion angle control unit 300, and current control is performed (step S50).
　なお、図１３～図１５におけるデータ入力及び演算等の順番は適宜変更可能である。 The order of data input and calculation in FIGS. 13 to 15 can be changed as appropriate.
　本実施形態での据切り特性補正部の効果について、図１６を参照して説明する。 The effect of the stationary characteristic correction unit in this embodiment will be described with reference to FIG.
　図１６は、車速Ｖｓが０ｋｍ／ｈで操舵した場合（据切り状態）の操舵角θｈと目標操舵トルクＴｒｅｆの変化の様子を示す線図の概念図である。据切り特性補正部の効果に焦点を当てるべく、基本マップの特性は、トルク信号Ｔｒｅｆ＿ａが操舵角θｈの大きさ｜θｈ｜に比例し、｜θｈ｜が９０ｄｅｇでトルク信号Ｔｒｅｆ＿ａが２Ｎｍとなる特性とし、ダンパゲインＤＧはゼロとしている。また、据切り特性演算部２４１でのヒステリシス特性は図９に示される特性とし、車速感応ゲイン部２４２での車速感応ゲインの特性は図１０に示される特性とする。よって、実質的には、図１６は直線状の基本マップと２．０のゲインを乗算されたヒステリシス特性による線図となっている。 FIG. 16 is a conceptual diagram of a diagram showing how the steering angle θh and the target steering torque Tref change when the vehicle speed Vs is steered at 0 km / h (stationary state). In order to focus on the effect of the stationary characteristic correction unit, the characteristics of the basic map are that the torque signal Tref_a is proportional to the magnitude of the steering angle θh | θh |, | θh | is 90 deg, and the torque signal Tref_a is 2 Nm. and then, damper gain D G is set to zero. Further, the hysteresis characteristic of the stationary characteristic calculation unit 241 is the characteristic shown in FIG. 9, and the characteristic of the vehicle speed sensitive gain in the vehicle speed sensitive gain unit 242 is the characteristic shown in FIG. Therefore, substantially, FIG. 16 is a diagram based on a linear basic map and a hysteresis characteristic multiplied by a gain of 2.0.
　捩れ角制御部３００の制御により目標操舵トルクＴｒｅｆ相当の捩れ角を実現することができるので、据切り特性補正部２４０の機能により目標操舵トルクを図１６のように変化させることによって、据切り状態での線図特性を実現することができる。 Since a twist angle equivalent to the target steering torque Tref can be realized by controlling the twist angle control unit 300, the target steering torque is changed by the function of the stationary characteristic correction unit 240 as shown in FIG. It is possible to realize the diagram characteristics in.
　第１実施形態での目標操舵トルク生成部２００は基本マップ部２１０、ダンパ演算部（ダンパゲイン部２３０及び乗算部２５０）及び据切り特性補正部２４０を備えているが、所望の据切り特性の実現のみに特化し、据切り特性補正部２４０のみを備える構成としても良い。この場合の目標操舵トルク生成部の構成例（第２実施形態）を図１７に示す。目標操舵トルク生成部６００では、据切り特性補正部２４０から出力されるトルク信号Ｔｒｅｆ＿ｃが、目標操舵トルクＴｒｅｆとして出力されることになる。なお、目標操舵トルク生成部を、基本マップ部２１０又はダンパ演算部と据切り特性補正部２４０を組み合わせた構成としても良い。 The target steering torque generation unit 200 in the first embodiment includes a basic map unit 210, a damper calculation unit (damper gain unit 230 and multiplication unit 250), and a stationary characteristic correction unit 240, but realizes a desired stationary characteristic. A configuration may be configured in which only the stationary characteristic correction unit 240 is provided, specializing only in the stationary characteristic correction unit 240. FIG. 17 shows a configuration example (second embodiment) of the target steering torque generation unit in this case. In the target steering torque generation unit 600, the torque signal Tref_c output from the stationary characteristic correction unit 240 is output as the target steering torque Tref. The target steering torque generation unit may be configured by combining the basic map unit 210 or the damper calculation unit and the stationary characteristic correction unit 240.
　第１及び第２実施形態での捩れ角制御部から出力されるモータ電流指令値Ｉｍｃに、従来のＥＰＳにおいて操舵トルクに基づいて演算される電流指令値（以下、「アシスト電流指令値」とする）を、例えば、図２に示される電流指令値演算部３１から出力される電流指令値Ｉｒｅｆ１又は電流指令値Ｉｒｅｆ１に補償信号ＣＭを加算した電流指令値Ｉｒｅｆ２等を加算して良い。 The motor current command value Imc output from the torsion angle control unit in the first and second embodiments is referred to as a current command value calculated based on the steering torque in the conventional EPS (hereinafter, referred to as "assist current command value"). ) May be added, for example, to the current command value Iref1 output from the current command value calculation unit 31 shown in FIG. 2, or the current command value Iref2 obtained by adding the compensation signal CM to the current command value Iref1.
　第１実施形態に対して、上記の内容を適用した構成例（第３実施形態）を図１８に示す。アシスト制御部７００は、電流指令値演算部３１、又は、電流指令値演算部３１、補償信号生成部３４及び加算部３２Ａから構成される。アシスト制御部７００から出力されるアシスト電流指令値Ｉａｃ（図２における電流指令値Ｉｒｅｆ１又はＩｒｅｆ２に相当）と、捩れ角制御部３００から出力されるモータ電流指令値Ｉｍｃは、加算部７１０で加算され、加算結果である電流指令値Ｉｃは電流制限部７２０に入力され、最大電流を制限された電流指令値Ｉｃｍに基づいてモータを駆動し、電流制御が実施される。 FIG. 18 shows a configuration example (third embodiment) to which the above contents are applied to the first embodiment. The assist control unit 700 includes a current command value calculation unit 31, a current command value calculation unit 31, a compensation signal generation unit 34, and an addition unit 32A. The assist current command value Iac output from the assist control unit 700 (corresponding to the current command value Iref1 or Iref2 in FIG. 2) and the motor current command value Imcc output from the twist angle control unit 300 are added by the addition unit 710. The current command value Ic, which is the result of addition, is input to the current limiting unit 720, and the motor is driven based on the current command value Icm in which the maximum current is limited, and current control is performed.
　第１～第３実施形態のうち、基本マップ部２１０を備える目標操舵トルク生成部２００において、基本マップ部２１０の前段又は後段に位相補償を行なう位相補償部２６０を挿入しても良い。つまり、図５中の破線で囲まれた領域Ｒの構成を、図１９（Ａ）又は（Ｂ）に示されるような構成にしても良い。位相補償部２６０において、位相補償として位相進み補償を設定し、例えば、分子のカットオフ周波数を１．０Ｈｚ、分母のカットオフ周波数を１．３Ｈｚとした１次フィルタで位相進み補償を行う場合、スッキリしたフィールを実現することができる。目標操舵トルク生成部に関しては、操舵角に基づいた構成であるならば、上述の構成に限られない。 In the target steering torque generation unit 200 including the basic map unit 210 in the first to third embodiments, the phase compensation unit 260 that performs phase compensation may be inserted in the front stage or the rear stage of the basic map unit 210. That is, the configuration of the region R surrounded by the broken line in FIG. 5 may be configured as shown in FIGS. 19A or 19B. In the phase compensation unit 260, when phase advance compensation is set as phase compensation and, for example, phase advance compensation is performed by a primary filter having a numerator cutoff frequency of 1.0 Hz and a denominator cutoff frequency of 1.3 Hz. A refreshing feel can be achieved. The target steering torque generating unit is not limited to the above configuration as long as it has a configuration based on the steering angle.
　また、ＥＰＳ制御システムが安定している場合は、安定化補償部を省略しても良い。出力制限部も省略可能である。 Also, if the EPS control system is stable, the stabilization compensation unit may be omitted. The output limiting unit can also be omitted.
　図１及び図３では本発明をコラム型ＥＰＳに適用しているが、本発明はコラム型等の上流型に限られず、ラック＆ピニオン等の下流型ＥＰＳにも適用可能である。更に、目標捩れ角に基づくフィードバック制御を行うということでは、トーションバー（バネ定数任意）及び捩れ角検出用のセンサを少なくとも備えるステアバイワイヤ（ＳＢＷ）反力装置等にも適用可能である。本発明を、トーションバーを備えたＳＢＷ反力装置に適用した場合の実施形態（第４実施形態）について説明する。 Although the present invention is applied to the column type EPS in FIGS. 1 and 3, the present invention is not limited to the upstream type such as the column type, and can be applied to the downstream type EPS such as the rack and pinion. Further, by performing feedback control based on the target torsion angle, it can be applied to a steer-by-wire (SBW) reaction force device having at least a torsion bar (arbitrary spring constant) and a sensor for detecting the torsion angle. An embodiment (fourth embodiment) when the present invention is applied to an SBW reaction force device provided with a torsion bar will be described.
　まずは、ＳＢＷ反力装置を含むＳＢＷシステム全体について説明する。図２０はＳＢＷシステムの構成例を、図１に示される電動パワーステアリング装置の一般的な構成に対応させて示した図である。なお、同一構成には同一符号を付し、詳細な説明は省略する。 First, the entire SBW system including the SBW reaction force device will be described. FIG. 20 is a diagram showing a configuration example of the SBW system corresponding to a general configuration of the electric power steering device shown in FIG. The same components are designated by the same reference numerals, and detailed description thereof will be omitted.
　ＳＢＷシステムは、ユニバーサルジョイント４ａにてコラム軸２と機械的に結合されるインターミディエイトシャフトがなく、ハンドル１の操作を電気信号によって操向車輪８Ｌ，８Ｒ等からなる転舵機構に伝えるシステムである。図２０に示されるように、ＳＢＷシステムは反力装置６０及び駆動装置７０を備え、コントロールユニット（ＥＣＵ）５０が両装置の制御を行う。反力装置６０は、舵角センサ１４にて操舵角θｈの検出を行うと同時に、操向車輪８Ｌ，８Ｒから伝わる車両の運動状態を反力トルクとして運転者に伝達する。反力トルクは、反力用モータ６１により生成される。なお、ＳＢＷシステムの中には反力装置内にトーションバーを有さないタイプもあるが、本発明を適用するＳＢＷシステムはトーションバーを有するタイプであり、トルクセンサ１０にて操舵トルクＴｓを検出する。また、角度センサ７４が、反力用モータ６１のモータ角θｍを検出する。駆動装置７０は、運転者によるハンドル１の操舵に合わせて、駆動用モータ７１を駆動し、その駆動力を、ギア７２を介してピニオンラック機構５に付与し、タイロッド６ａ，６ｂを経て、操向車輪８Ｌ，８Ｒを転舵する。ピニオンラック機構５の近傍には角度センサ７３が配置されており、操向車輪８Ｌ，８Ｒの転舵角θｔを検出する。ＥＣＵ５０は、反力装置６０及び駆動装置７０を協調制御するために、両装置から出力される操舵角θｈや転舵角θｔ等の情報に加え、車速センサ１２からの車速Ｖｓ等を基に、反力用モータ６１を駆動制御する電圧制御指令値Ｖｒｅｆ１及び駆動用モータ７１を駆動制御する電圧制御指令値Ｖｒｅｆ２を生成する。 The SBW system is a system that does not have an intermediate shaft that is mechanically coupled to the column shaft 2 by a universal joint 4a, and transmits the operation of the handle 1 to a steering mechanism composed of steering wheels 8L, 8R, etc. by an electric signal. .. As shown in FIG. 20, the SBW system includes a reaction force device 60 and a drive device 70, and a control unit (ECU) 50 controls both devices. The reaction force device 60 detects the steering angle θh by the steering angle sensor 14, and at the same time, transmits the motion state of the vehicle transmitted from the steering wheels 8L and 8R to the driver as reaction force torque. The reaction force torque is generated by the reaction force motor 61. Although some SBW systems do not have a torsion bar in the reaction force device, the SBW system to which the present invention is applied is a type that has a torsion bar, and the torque sensor 10 detects the steering torque Ts. To do. Further, the angle sensor 74 detects the motor angle θm of the reaction force motor 61. The drive device 70 drives the drive motor 71 in accordance with the steering of the steering wheel 1 by the driver, applies the driving force to the pinion rack mechanism 5 via the gear 72, and operates the pinion rack mechanism 5 via the tie rods 6a and 6b. Steer the facing wheels 8L and 8R. An angle sensor 73 is arranged in the vicinity of the pinion rack mechanism 5 to detect the steering angle θt of the steering wheels 8L and 8R. In order to coordinately control the reaction force device 60 and the drive device 70, the ECU 50 adds information such as steering angle θh and steering angle θt output from both devices, and based on vehicle speed Vs from the vehicle speed sensor 12 and the like. The voltage control command value Vref1 that drives and controls the reaction force motor 61 and the voltage control command value Vref2 that drives and controls the drive motor 71 are generated.
　このようなＳＢＷシステムに本発明を適用した第４実施形態の構成について説明する。 The configuration of the fourth embodiment to which the present invention is applied to such an SBW system will be described.
　図２１は第４実施形態の構成を示すブロック図である。第４実施形態は、捩れ角Δθに対する制御（以下、「捩れ角制御」とする）と、転舵角θｔに対する制御（以下、「転舵角制御」とする）を行い、反力装置を捩れ角制御で制御し、駆動装置を転舵角制御で制御する。なお、駆動装置は他の制御方法で制御しても良い。 FIG. 21 is a block diagram showing the configuration of the fourth embodiment. In the fourth embodiment, the reaction force device is twisted by controlling the twist angle Δθ (hereinafter referred to as “twist angle control”) and controlling the steering angle θt (hereinafter referred to as “turning angle control”). It is controlled by angle control, and the drive unit is controlled by steering angle control. The drive device may be controlled by another control method.
　捩れ角制御では、第１実施形態と同様の構成及び動作により、捩れ角Δθが、操舵角θｈ等を用いて目標操舵トルク生成部２００及び変換部４００を経て算出される目標捩れ角Δθｒｅｆに追従するような制御を行う。モータ角θｍは角度センサ７４で検出され、モータ角速度ωｍは、角速度演算部９５１にてモータ角θｍを微分することにより算出される。転舵角θｔは角度センサ７３で検出される。また、第１実施形態ではＥＰＳ操舵系／車両系１００内の処理として詳細な説明は行われていないが、電流制御部１３０は、図２に示される減算部３２Ｂ、ＰＩ制御部３５、ＰＷＭ制御部３６及びインバータ３７と同様の構成及び動作により、捩れ角制御部３００から出力されるモータ電流指令値Ｉｍｃ及びモータ電流検出器１４０で検出される反力用モータ６１の電流値Ｉｍｒに基づいて、反力用モータ６１を駆動して、電流制御を行う。 In the torsion angle control, the torsion angle Δθ follows the target torsion angle Δθref calculated through the target steering torque generating unit 200 and the conversion unit 400 using the steering angle θh and the like by the same configuration and operation as in the first embodiment. Control to do so. The motor angle θm is detected by the angle sensor 74, and the motor angular velocity ωm is calculated by differentiating the motor angle θm by the angular velocity calculation unit 951. The steering angle θt is detected by the angle sensor 73. Further, although the processing in the EPS steering system / vehicle system 100 is not described in detail in the first embodiment, the current control unit 130 includes the subtraction unit 32B, the PI control unit 35, and the PWM control shown in FIG. With the same configuration and operation as the unit 36 and the inverter 37, based on the motor current command value Imc output from the torsion angle control unit 300 and the current value Imr of the reaction force motor 61 detected by the motor current detector 140. The reaction force motor 61 is driven to control the current.
　転舵角制御では、目標転舵角生成部９１０にて操舵角θｈに基づいて目標転舵角θｔｒｅｆが生成され、目標転舵角θｔｒｅｆは転舵角θｔと共に転舵角制御部９２０に入力され、転舵角制御部９２０にて、転舵角θｔが目標転舵角θｔｒｅｆとなるようなモータ電流指令値Ｉｍｃｔが演算される。そして、モータ電流指令値Ｉｍｃｔ及びモータ電流検出器９４０で検出される駆動用モータ７１の電流値Ｉｍｄに基づいて、電流制御部９３０が、電流制御部１３０と同様の構成及び動作により、駆動用モータ７１を駆動して、電流制御を行う。 In the steering angle control, the target steering angle generation unit 910 generates a target steering angle θtref based on the steering angle θh, and the target steering angle θtref is input to the steering angle control unit 920 together with the steering angle θt. The steering angle control unit 920 calculates the motor current command value Imct so that the steering angle θt becomes the target steering angle θtref. Then, based on the motor current command value Imct and the current value Imd of the drive motor 71 detected by the motor current detector 940, the current control unit 930 has the same configuration and operation as the current control unit 130, and the drive motor has the same configuration and operation. The 71 is driven to control the current.
　目標転舵角生成部９１０の構成例を図２２に示す。目標転舵角生成部９１０は、制限部９３１、レート制限部９３２及び補正部９３３を備える。 FIG. 22 shows a configuration example of the target steering angle generation unit 910. The target steering angle generation unit 910 includes a limiting unit 931, a rate limiting unit 932, and a correction unit 933.
　制限部９３１は、操舵角θｈの上下限値を制限して、操舵角θｈ１を出力する。ＳＡＴ情報補正部２５０内の制限部２５６及び捩れ角制御部３００内の出力制限部３５０と同様に、操舵角θｈに対する上限値及び下限値を予め設定して制限をかける。 The limiting unit 931 limits the upper and lower limits of the steering angle θh and outputs the steering angle θh1. Similar to the limiting unit 256 in the SAT information correction unit 250 and the output limiting unit 350 in the torsion angle control unit 300, the upper limit value and the lower limit value for the steering angle θh are set in advance to limit.
　レート制限部９３２は、操舵角の急変を回避するために、操舵角θｈ１の変化量に対して制限値を設定して制限をかけ、操舵角θｈ２を出力する。例えば、１サンプル前の操舵角θｈ１からの差分を変化量とし、その変化量の絶対値が所定の値（制限値）より大きい場合、変化量の絶対値が制限値となるように、操舵角θｈ１を加減算し、操舵角θｈ２として出力し、制限値以下の場合は、操舵角θｈ１をそのまま操舵角θｈ２として出力する。なお、変化量の絶対値に対して制限値を設定するのではなく、変化量に対して上限値及び下限値を設定して制限をかけるようにしても良く、変化量ではなく変化率や差分率に対して制限をかけるようにしても良い。 The rate limiting unit 932 sets and limits the amount of change in the steering angle θh1 in order to avoid a sudden change in the steering angle, and outputs the steering angle θh2. For example, the difference from the steering angle θh1 one sample before is used as the change amount, and when the absolute value of the change amount is larger than a predetermined value (limit value), the steering angle is set so that the absolute value of the change amount becomes the limit value. θh1 is added or subtracted and output as the steering angle θh2, and if it is equal to or less than the limit value, the steering angle θh1 is output as it is as the steering angle θh2. Instead of setting a limit value for the absolute value of the amount of change, an upper limit value and a lower limit value may be set for the amount of change to limit the amount of change. You may want to limit the rate.
　補正部９３３は、操舵角θｈ２を補正して、目標転舵角θｔｒｅｆを出力する。例えば、目標操舵トルク生成部２００内の基本マップ部２１０のように、操舵角θｈ２の大きさ｜θｈ２｜に対する目標転舵角θｔｒｅｆの特性を定義したマップを用いて、操舵角θｈ２より目標転舵角θｔｒｅｆを求める。或いは、単純に、操舵角θｈ２に所定のゲインを乗算することにより、目標転舵角θｔｒｅｆを求めるようにしても良い。 The correction unit 933 corrects the steering angle θh2 and outputs the target steering angle θtref. For example, using a map that defines the characteristics of the target steering angle θtref with respect to the magnitude | θh2 | of the steering angle θh2, such as the basic map unit 210 in the target steering torque generating unit 200, the target steering from the steering angle θh2. Find the angle θtref. Alternatively, the target steering angle θtref may be obtained by simply multiplying the steering angle θh2 by a predetermined gain.
　転舵角制御部９２０の構成例を図２３に示す。転舵角制御部９２０は、図１１に示される捩れ角制御部３００の構成例において安定化補償部３４０及び加算部３６２を除いた構成と同様の構成をしており、目標捩れ角Δθｒｅｆ及び捩れ角Δθの代わりに目標転舵角θｔｒｅｆ及び転舵角θｔを入力し、転舵角フィードバック（ＦＢ）補償部９２１、転舵角速度演算部９２２、速度制御部９２３、出力制限部９２６及び減算部９２７が、それぞれ捩れ角ＦＢ補償部３１０、捩れ角速度演算部３２０、速度制御部３３０、出力制限部３５０及び減算部３６１と同様の構成で同様の動作を行う。 FIG. 23 shows a configuration example of the steering angle control unit 920. The steering angle control unit 920 has the same configuration as the configuration example of the torsion angle control unit 300 shown in FIG. 11 excluding the stabilization compensation unit 340 and the addition unit 362, and has a target torsion angle Δθref and a torsion. The target steering angle θtref and steering angle θt are input instead of the angle Δθ, and the steering angle feedback (FB) compensation unit 921, the steering angular velocity calculation unit 922, the speed control unit 923, the output limiting unit 926 and the subtraction unit 927 are input. However, the same operation is performed with the same configurations as the torsion angle FB compensation unit 310, the torsion angular velocity calculation unit 320, the speed control unit 330, the output limiting unit 350, and the subtraction unit 361, respectively.
　このような構成において、第４実施形態の動作例を図２４のフローチャートを参照して説明する。 In such a configuration, an operation example of the fourth embodiment will be described with reference to the flowchart of FIG.
　動作を開始すると、角度センサ７３は転舵角θｔを検出し、角度センサ７４はモータ角θｍを検出し（ステップＳ１１０）、転舵角θｔは転舵角制御部９２０に、モータ角θｍは角速度演算部９５１にそれぞれ入力される。 When the operation is started, the angle sensor 73 detects the steering angle θt, the angle sensor 74 detects the motor angle θm (step S110), the steering angle θt is the steering angle control unit 920, and the motor angle θm is the angular velocity. Each is input to the calculation unit 951.
　角速度演算部９５１は、モータ角θｍを微分してモータ角速度ωｍを算出し、右切り／左切り判定部４００に出力する（ステップＳ１２０）。 The angular velocity calculation unit 951 differentiates the motor angle θm to calculate the motor angular velocity ωm, and outputs the motor angular velocity to the right / left turn determination unit 400 (step S120).
　その後、図１３に示されるステップＳ１０～Ｓ５０と同様の動作を実行し、反力用モータ６１を駆動し、電流制御を実施する（ステップＳ１３０～Ｓ１７０）。 After that, the same operation as in steps S10 to S50 shown in FIG. 13 is executed, the reaction force motor 61 is driven, and current control is performed (steps S130 to S170).
　一方、転舵角制御においては、目標転舵角生成部９１０が操舵角θｈを入力し、操舵角θｈは制限部９３１に入力される。制限部９３１は、予め設定された上限値及び下限値により操舵角θｈの上下限値を制限し（ステップＳ１８０）、操舵角θｈ１としてレート制限部９３２に出力する。レート制限部９３２は、予め設定された制限値により操舵角θｈ１の変化量に対して制限をかけ（ステップＳ１９０）、操舵角θｈ２として補正部９３３に出力する。補正部９３３は、操舵角θｈ２を補正して目標転舵角θｔｒｅｆを求め（ステップＳ２００）、転舵角制御部９２０に出力する。 On the other hand, in the steering angle control, the target steering angle generation unit 910 inputs the steering angle θh, and the steering angle θh is input to the limiting unit 931. The limiting unit 931 limits the upper and lower limit values of the steering angle θh by preset upper and lower limit values (step S180), and outputs the steering angle θh1 to the rate limiting unit 932. The rate limiting unit 932 limits the amount of change in the steering angle θh1 by a preset limit value (step S190), and outputs the steering angle θh2 to the correction unit 933. The correction unit 933 corrects the steering angle θh2 to obtain the target steering angle θtref (step S200), and outputs the steering angle θh2 to the steering angle control unit 920.
　転舵角θｔ及び目標転舵角θｔｒｅｆを入力した転舵角制御部９２０は、減算部９２７にて目標転舵角θｔｒｅｆから転舵角θｔを減算することにより、偏差Δθｔ０を算出する（ステップＳ２１０）。偏差Δθｔ０は転舵角ＦＢ補償部９２１に入力され、転舵角ＦＢ補償部９２１は、偏差Δθｔ０に補償値を乗算することにより偏差Δθｔ０を補償し（ステップＳ２２０）、目標転舵角速度ωｔｒｅｆを速度制御部９２３に出力する。転舵角速度演算部９２２は転舵角θｔを入力し、転舵角θｔに対する微分演算により転舵角速度ωｔｔを算出し（ステップＳ２３０）、速度制御部９２３に出力する。速度制御部９２３は、速度制御部３３０と同様にＩ－Ｐ制御によりモータ電流指令値Ｉｍｃｔａを算出し（ステップＳ２４０）、出力制限部９２６に出力する。出力制限部９２６は、予め設定された上限値及び下限値によりモータ電流指令値Ｉｍｃｔａの上下限値を制限し（ステップＳ２５０）、モータ電流指令値Ｉｍｃｔとして出力する（ステップＳ２６０）。 The steering angle control unit 920, which has input the steering angle θt and the target steering angle θtref, calculates the deviation Δθt 0 by subtracting the steering angle θt from the target steering angle θtref by the subtracting unit 927 (step). S210). Deviation Derutashitati 0 is input to the turning angle FB compensation unit 921, the turning angle FB compensation unit 921 compensates the deviation Derutashitati 0 by multiplying the compensation value to the deviation Δθt 0 (step S220), the target turning angular velocity The ω tref is output to the speed control unit 923. The steering angular velocity calculation unit 922 inputs the steering angle θt, calculates the steering angular velocity ωtt by a differential calculation with respect to the steering angle θt (step S230), and outputs the steering angular velocity ωtt to the speed control unit 923. The speed control unit 923 calculates the motor current command value Imcta by IP control in the same manner as the speed control unit 330 (step S240), and outputs the motor current command value Imcta to the output limiting unit 926. The output limiting unit 926 limits the upper and lower limit values of the motor current command value Imcta by the preset upper limit value and lower limit value (step S250), and outputs the motor current command value Imct as the motor current command value Imct (step S260).
　モータ電流指令値Ｉｍｃｔは電流制御部９３０に入力され、電流制御部９３０は、モータ電流指令値Ｉｍｃｔ及びモータ電流検出器９４０で検出された駆動用モータ７１の電流値Ｉｍｄに基づいて、駆動用モータ７１を駆動し、電流制御を実施する（ステップＳ２７０）。 The motor current command value Imct is input to the current control unit 930, and the current control unit 930 is based on the motor current command value Imct and the current value Imd of the drive motor 71 detected by the motor current detector 940. 71 is driven and current control is performed (step S270).
　なお、図２４におけるデータ入力及び演算等の順番は適宜変更可能である。また、転舵角制御部９２０内の速度制御部９２３は、捩れ角制御部３００内の速度制御部３３０と同様に、Ｉ－Ｐ制御ではなく、ＰＩ制御、Ｐ制御、ＰＩＤ制御、ＰＩ－Ｄ制御等、実現可能で、Ｐ、Ｉ及びＤのいずれかの制御を用いていれば良く、更に、転舵角制御部９２０及び捩れ角制御部３００での追従制御は、一般的に用いられている制御構造で行っても良い。 The order of data input and calculation in FIG. 24 can be changed as appropriate. Further, the speed control unit 923 in the steering angle control unit 920 is not the IP control but the PI control, the P control, the PID control, and the PI-D, like the speed control unit 330 in the twist angle control unit 300. Control and the like are feasible, and any of P, I, and D controls may be used, and follow-up control by the steering angle control unit 920 and the twist angle control unit 300 is generally used. The control structure may be used.
　第４実施形態では、図２０に示されるように、１つのＥＣＵ５０で反力装置６０及び駆動装置７０の制御を行っているが、反力装置６０用のＥＣＵと駆動装置７０用のＥＣＵをそれぞれ設けても良い。この場合、ＥＣＵ同士は通信によりデータの送受信を行うことになる。また、図２０に示されるＳＢＷシステムは反力装置６０と駆動装置７０の間には機械的な結合を持たないが、システムに異常が発生した場合に、コラム軸２と転舵機構をクラッチ等で機械的に結合する機械的トルク伝達機構を備えるＳＢＷシステムにも、本発明は適用可能である。このようなＳＢＷシステムでは、システム正常時はクラッチをオフにして機械的トルク伝達を開放状態とし、システム異常時はクラッチをオンにして機械的トルク伝達を可能状態とする。 In the fourth embodiment, as shown in FIG. 20, one ECU 50 controls the reaction force device 60 and the drive device 70, but the ECU for the reaction force device 60 and the ECU for the drive device 70 are used, respectively. It may be provided. In this case, the ECUs transmit and receive data by communication. Further, the SBW system shown in FIG. 20 does not have a mechanical coupling between the reaction force device 60 and the drive device 70, but when an abnormality occurs in the system, the column shaft 2 and the steering mechanism are clutched or the like. The present invention is also applicable to SBW systems provided with a mechanical torque transmission mechanism that mechanically couples with. In such an SBW system, when the system is normal, the clutch is turned off to open the mechanical torque transmission, and when the system is abnormal, the clutch is turned on to enable the mechanical torque transmission.
　上述の第１～第４実施形態での捩れ角制御部３００及び第３実施形態でのアシスト制御部７００は、直接的にモータ電流指令値Ｉｍｃ及びアシスト電流指令値Ｉａｃを演算しているが、それらを演算する前に、先ず出力したいモータトルク（目標トルク）を演算してから、モータ電流指令値及びアシスト電流指令値を演算するようにしても良い。この場合、モータトルクからモータ電流指令値及びアシスト電流指令値を求めるには、一般的に用いられている、モータ電流とモータトルクの関係を使用する。 The twist angle control unit 300 in the first to fourth embodiments and the assist control unit 700 in the third embodiment directly calculate the motor current command value Imc and the assist current command value Iac. Before calculating them, the motor torque (target torque) to be output may be calculated first, and then the motor current command value and the assist current command value may be calculated. In this case, in order to obtain the motor current command value and the assist current command value from the motor torque, the generally used relationship between the motor current and the motor torque is used.
１　　　　　　　　　　　ハンドル
２　　　　　　　　　　　コラム軸（ステアリングシャフト、ハンドル軸）
２Ａ　　　　　　　　　　トーションバー
３　　　　　　　　　　　減速機構
１０　　　　　　　　　　トルクセンサ
１２　　　　　　　　　　車速センサ
１４　　　　　　　　　　舵角センサ
２０　　　　　　　　　　モータ
３０、５０　　　　　　　コントロールユニット（ＥＣＵ）
３１　　　　　　　　　　電流指令値演算部
３３、７２０　　　　　　電流制限部
３４　　　　　　　　　　補償信号生成部
３８、１４０、９４０　　モータ電流検出器
６０　　　　　　　　　　反力装置
６１　　　　　　　　　　反力用モータ
７０　　　　　　　　　　駆動装置
７１　　　　　　　　　　駆動用モータ
７２　　　　　　　　　　ギア
７３、７４　　　　　　　角度センサ
１００　　　　　　　　　ＥＰＳ操舵系／車両系
１３０、９３０　　　　　電流制御部
２００、６００　　　　　目標操舵トルク生成部
２１０　　　　　　　　　基本マップ部
２１１　　　　　　　　　符号部
２３０　　　　　　　　　ダンパゲイン部
２４０　　　　　　　　　据切り特性補正部
２４１　　　　　　　　　据切り特性演算部
２４２　　　　　　　　　車速感応ゲイン部
２６０　　　　　　　　　位相補償部
３００　　　　　　　　　捩れ角制御部
３１０　　　　　　　　　捩れ角フィードバック（ＦＢ）補償部
３２０　　　　　　　　　捩れ角速度演算部
３３０、９２３　　　　　速度制御部
３４０　　　　　　　　　安定化補償部
３５０、９２６　　　　　出力制限部
４００　　　　　　　　　変換部
５００　　　　　　　　　右切り／左切り判定部
７００　　　　　　　　　アシスト制御部
９１０　　　　　　　　　目標転舵角生成部
９２０　　　　　　　　　転舵角制御部
９２１　　　　　　　　　転舵角フィードバック（ＦＢ）補償部
９２２　　　　　　　　　転舵角速度演算部
９３１　　　　　　　　　制限部
９３２　　　　　　　　　レート制限部
９３３　　　　　　　　　補正部
９５１　　　　　　　　　角速度演算部 1 Handle 2 Column shaft (steering shaft, handle shaft)
2A Torsion bar 3 Deceleration mechanism 10 Torque sensor 12 Vehicle speed sensor 14 Steering angle sensor 20 Motor 30, 50 Control unit (ECU)
31 Current command value calculation unit 33, 720 Current limit unit 34 Compensation signal generation unit 38, 140, 940 Motor current detector 60 Reaction force device 61 Reaction force motor 70 Drive device 71 Drive motor 72 Gear 73, 74 Angle sensor 100 EPS Steering system / Vehicle system 130, 930 Current control unit 200, 600 Target steering torque generation unit 210 Basic map unit 211 Code unit 230 Damper gain unit 240 Stationary characteristic correction unit 241 Stationary characteristic calculation unit 242 Vehicle speed sensitive gain unit 260 Phase compensation Unit 300 Twist angle control unit 310 Twist angle feedback (FB) Compensation unit 320 Twist angle speed calculation unit 330, 923 Speed control unit 340 Stabilization compensation unit 350, 926 Output limit unit 400 Conversion unit 500 Right / left turn judgment unit 700 Assist Control unit 910 Target steering angle generation unit 920 Steering angle control unit 921 Steering angle feedback (FB) Compensation unit 922 Steering angle speed calculation unit 931 Limiting unit 932 Rate limiting unit 933 Correction unit 951 Angle speed calculation unit

Claims (7)

  1. 　任意のバネ定数を有するトーションバー及び前記トーションバーの捩れ角を検出するセンサを少なくとも備え、モータを駆動制御することにより、操舵系をアシスト制御する車両用操向装置において、
    　目標操舵トルクを生成する目標操舵トルク生成部と、
    　前記目標操舵トルクを目標捩れ角に変換する変換部と、
    　前記目標捩れ角に対して前記捩れ角を追従させるようなモータ電流指令値を演算する捩れ角制御部とを備え、
    　前記目標操舵トルク生成部が、
    　操舵角に応じた所望の据切り特性に基づいて第１トルク信号を求める据切り特性補正部を具備し、前記第１トルク信号を前記目標操舵トルクとして出力し、
    　前記モータ電流指令値に基づいて前記モータを駆動制御することを特徴とする車両用操向装置。     In a vehicle steering device that includes at least a torsion bar having an arbitrary spring constant and a sensor that detects the twist angle of the torsion bar, and assists and controls the steering system by driving and controlling the motor.
    A target steering torque generator that generates a target steering torque,
    A conversion unit that converts the target steering torque into a target torsion angle,
    It is provided with a twist angle control unit that calculates a motor current command value that causes the twist angle to follow the target twist angle.
    The target steering torque generator
    A stationary characteristic correction unit for obtaining a first torque signal based on a desired stationary characteristic according to a steering angle is provided, and the first torque signal is output as the target steering torque.
    A vehicle steering device characterized in that the motor is driven and controlled based on the motor current command value.
  2. 　前記据切り特性補正部が、
    　操舵状態及び前記操舵角を用いてヒステリシス補正を行って基本トルク信号を求める据切り特性演算部を具備し、前記基本トルク信号を前記第１トルク信号として出力する請求項１に記載の車両用操向装置。     The stationary characteristic correction unit
    The vehicle operation according to claim 1, further comprising a stationary characteristic calculation unit for obtaining a basic torque signal by performing hysteresis correction using the steering state and the steering angle, and outputting the basic torque signal as the first torque signal. Direction device.
  3. 　前記据切り特性補正部が、
    　前記基本トルク信号に車速感応ゲインを乗算することにより前記第１トルク信号を算出する車速感応ゲイン部を更に具備する請求項２に記載の車両用操向装置。     The stationary characteristic correction unit
    The vehicle steering device according to claim 2, further comprising a vehicle speed-sensitive gain unit that calculates the first torque signal by multiplying the basic torque signal by the vehicle speed-sensitive gain.
  4. 　前記車速感応ゲインが、車速が大きくなるに従って小さくなる特性である請求項３に記載の車両用操向装置。 The vehicle steering device according to claim 3, wherein the vehicle speed-sensitive gain decreases as the vehicle speed increases.
  5. 　前記目標操舵トルク生成部が、
    　基本マップを用いて前記操舵角及び車速より第２トルク信号を求める基本マップ部と、
    　車速感応であるダンパゲインマップを用いて角速度情報に基づいて第３トルク信号を求めるダンパ演算部とを更に具備し、
    　前記第２トルク信号及び前記第３トルク信号の内の少なくとも１つの信号並びに前記第１トルク信号より前記目標操舵トルクを算出する請求項１乃至４のいずれかに記載の車両用操向装置。     The target steering torque generator
    A basic map unit that obtains a second torque signal from the steering angle and vehicle speed using the basic map,
    It is further equipped with a damper calculation unit that obtains a third torque signal based on angular velocity information using a damper gain map that is sensitive to vehicle speed.
    The vehicle steering device according to any one of claims 1 to 4, wherein the target steering torque is calculated from at least one signal of the second torque signal and the third torque signal and the first torque signal.
  6. 　前記基本マップが車速感応である請求項５に記載の車両用操向装置。 The vehicle steering device according to claim 5, wherein the basic map is vehicle speed sensitive.
  7. 　前記目標操舵トルク生成部が、
    　前記基本マップ部の前段又は後段に、位相補償を行なう位相補償部を更に具備し、
    　前記基本マップ部及び前記位相補償部を介して、前記操舵角及び前記車速より前記第２トルク信号を求める請求項５又は６に記載の車両用操向装置。     The target steering torque generator
    A phase compensation unit that performs phase compensation is further provided in the front stage or the rear stage of the basic map unit.
    The vehicle steering device according to claim 5 or 6, wherein the second torque signal is obtained from the steering angle and the vehicle speed via the basic map unit and the phase compensation unit.
PCT/JP2019/049288 2019-03-08 2019-12-17 Vehicle steering device WO2020183838A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008168858A (en) * 2007-01-15 2008-07-24 Jtekt Corp Electric power steering device
JP2017056745A (en) * 2015-09-14 2017-03-23 日立オートモティブシステムズ株式会社 Power steering device
WO2018084190A1 (en) * 2016-11-07 2018-05-11 日本精工株式会社 Electric power steering apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008168858A (en) * 2007-01-15 2008-07-24 Jtekt Corp Electric power steering device
JP2017056745A (en) * 2015-09-14 2017-03-23 日立オートモティブシステムズ株式会社 Power steering device
WO2018084190A1 (en) * 2016-11-07 2018-05-11 日本精工株式会社 Electric power steering apparatus

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