JP2007237840A - Steering controlling device, automobile, and steering controlling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering controlling device which can maintain a stable vehicle behavior when an external turbulence is input, and to provide an automobile equipped with the steering controlling device, and a steering controlling method. <P>SOLUTION: At least one of a steering angle and a steering angle velocity is detected as a steering state amount. A plurality of disturbances having different frequency bands input in a vehicle are estimated based on a driver steering torque Ts and an electric current target value I<SP>*</SP>of a motor 13, and a steering angle α. Then, the output torque (electric current target value I<SP>*</SP>) of the motor 13 is corrected by a correction degree in response to the frequency band of the disturbance so as to suppress the disturbances. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a steering control device capable of adjusting a steering torque so as to suppress a vehicle behavior generated by disturbance input, an automobile equipped with the steering control device, and a steering control method.

As a conventional steering control device, a disturbance observer is used to separate road surface gradient disturbances and side wind disturbances from among disturbances in the vehicle width direction inputted to the vehicle, and estimate each of them. It is known to apply a steering assist torque so as to suppress the influence (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2004-98796

However, in the above-described conventional steering control device, when the driver detects the movement of the vehicle at the time of disturbance input and corrective steering is performed, the direction in which the steering assist torque is applied coincides with the direction of the corrective steering by the driver. Therefore, the steering by the control and the steering by the driver are synchronized, and the vehicle behavior becomes larger than intended by the driver, which may give the driver a sense of incongruity.
Accordingly, an object of the present invention is to provide a steering control device capable of maintaining a stable vehicle behavior when a disturbance is input, and an automobile equipped with the steering control device and a steering control method.

In order to solve the above problems, a steering control device according to the present invention includes:
A steering control device comprising an actuator capable of adjusting a steering torque and a control means for controlling an output torque of the actuator,
Steering state quantity detection means for detecting at least one of a steering angle and a steering angular velocity as a steering state quantity, a steering input by a driver, a steering input by the actuator, and an actual steering state quantity detected by the steering state quantity detection means And a plurality of disturbance estimation means for estimating a plurality of disturbances having different frequency bands input to the vehicle, and the output torque of the actuator is reduced so as to suppress the disturbance estimated by the disturbance estimation means. It is characterized by comprising a plurality of disturbance compensation means for correcting with a correction degree corresponding to the frequency band.

In addition, the automobile according to the present invention is
A vehicle equipped with a steering control device including a steering wheel installed at a front position of a driver's seat, an actuator capable of adjusting a steering torque generated in the steering wheel, and a control means for controlling an output torque of the actuator. And
A steering state amount detection means for detecting at least one of a steering angle and a steering angular velocity as a steering state amount; a steering input to the steering wheel by a driver; a steering input to the steering wheel by the actuator; and a steering state amount detection means. Based on the detected actual steering state quantity, a plurality of disturbance estimation means for estimating a plurality of disturbances having different frequency bands input to the vehicle, and the disturbance estimated by the disturbance estimation means are suppressed, And a plurality of disturbance compensation means for correcting the output torque of the actuator with a correction degree corresponding to the frequency band of the disturbance.

Further, the steering control method according to the present invention includes:
A steering control method comprising an actuator capable of adjusting a steering torque and a control means for controlling an output torque of the actuator,
Based on the steering input by the driver, the steering input by the actuator, and the actual steering state quantity, the actuator estimates a plurality of disturbances having different frequency bands input to the vehicle, and suppresses the disturbances. The output torque is corrected with a correction degree corresponding to the frequency band of the disturbance.

According to the steering control device of the present invention, a plurality of disturbances having different frequency bands input to the vehicle are estimated based on the steering input by the driver, the steering input by the actuator, and the actual steering state quantity, and the steering The output torque of the actuator whose torque can be adjusted is corrected with a correction degree corresponding to the frequency band of disturbance input to the vehicle.
Therefore, the degree of suppression of the disturbance can be changed according to the frequency band of the disturbance, such as suppressing all the disturbances in the low frequency band and suppressing a part of the disturbance in the high frequency band. The disturbance input in the frequency band can be recognized, and when the driver performs the correction steering in order to correct the vehicle behavior accompanying the disturbance input, the operation speed of the correction steering is reduced because the steering wheel feels heavy. The stability of the vehicle behavior can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
(Constitution)
FIG. 1 is a configuration diagram showing an embodiment when the steering control device of the present invention is applied to a vehicle equipped with an electric power steering system.
In the figure, reference numeral 1 denotes a steering wheel for a steering operation by the driver, 2 denotes a steering shaft, and 3 denotes a rack and pinion type gear mechanism. The rack and pinion gear mechanism 3 includes a pinion 3a formed integrally with the lower end of the steering shaft 2, and a rack shaft 3b meshing with the pinion 3a. The rack shaft 3b extends in the vehicle width direction at the front portion of the vehicle and is slidable in the left and right directions in the vehicle width direction, and both ends thereof are steered steering wheels 6, 7 via tie rods 4, 5. It is connected to.

The steering shaft 2 is provided with a torque sensor 11 that detects a steering torque Ts that is a steering input by the driver, and an electric power steering mechanism 12 that assists the steering force of the driver.
The electric power steering mechanism 12 assists the driver's steering force by converting the torque generated by the motor 13 into the rotational torque of the steering shaft 2 via the speed reducer 14. The motor current supplied to the motor 13 is controlled by an EPS controller 20 described later.

The rotation angle of the motor 13 is measured by the encoder 15, and the encoder signal is output to the EPS controller 20. In the present embodiment, the encoder signal is used as the steering angle, but the steering angle can be directly detected by a steering angle sensor or the like.
Further, the vehicle is provided with a vehicle speed sensor 16 for detecting the vehicle speed V, and a detection signal of the vehicle speed sensor 16 is also output to the EPS controller 20.

  The EPS controller 20 receives detection signals from the various sensors described above, and calculates the drive current of the motor 13 based on these detection signals (steering torque, motor rotation angle, vehicle speed, etc.). Then, the motor 13 is controlled and driven based on the calculated drive current while referring to the motor current detected by a motor current sensor (not shown) and the motor rotation angle detected by the encoder 15. Here, the power supplied to the motor 13 is supplied by the battery 18.

FIG. 2 is a control block diagram showing the configuration of the EPS controller 20.
This control block includes a target torque calculation unit 101, a target current calculation unit 102, a control voltage calculation unit 103, a drive current control unit 104, a disturbance compensation unit 105, and a target torque correction unit 106. .
In the target torque calculation unit 101, the steering torque Ts from the torque sensor 11, the vehicle speed V from the vehicle speed sensor 16, and the motor rotation angle (steering angle α) from the encoder 15 are input, and the assist control map stored in advance is referred to. Thus, a basic torque command value corresponding to the required assist amount is calculated.

  Although not shown, the target torque calculation unit 101 includes a static assist unit that generates an assist substantially proportional to the steering torque Ts to reduce the driver's steering load, and an inertia compensation assist unit that compensates the inertia of the motor. The basic torque command value is calculated by a damping assist unit that ensures steering damping and a steering wheel return assist unit that improves steering wheel return.

In the target current calculation unit 102, a target torque obtained by correcting the basic torque command value calculated by the target torque calculation unit 101 with a torque correction amount calculated by a disturbance compensation unit 105 described later is a drive current command value for the motor 13. Convert to motor current command value.
The control voltage calculation unit 103 calculates a motor applied voltage command value in motor PWM control based on the motor current command value calculated by the target current calculation unit 102.

  The drive current control unit 104 performs ON / OFF control of a switching element such as an FET in the drive circuit of the motor 13 based on the motor applied voltage command value calculated by the control voltage calculation unit 103, thereby driving the drive current of the motor 13. To control. Here, the drive current of the motor 13 is stably controlled by feeding back the current signal detected by the motor current sensor 13a to the current servo.

In the disturbance compensator 105, the steering torque Ts from the torque sensor 11, the motor rotation angle (steering angle α) from the encoder 15, and the motor current I from the motor current sensor 13a are input, and the disturbance input to the vehicle is frequencyd. The estimation is performed separately for each band, and a torque correction amount for suppressing these disturbances is calculated.
The target torque correction unit 106 corrects the basic torque command value by adding the basic torque command value calculated by the target torque calculation unit 101 and the torque correction amount calculated by the disturbance compensation unit 105, and The result is output to the target current calculation unit 102 described above.

  FIG. 3 is a diagram illustrating a frequency distribution of disturbances input to the vehicle. As shown in FIG. 3, there are roughly three disturbances input to the vehicle. [1] Low-frequency constant disturbance due to vehicle left-right difference and tire conicity left-right difference, [2] Very low-frequency disturbance generated by road surface cants, etc. [3] High-frequency disturbance due to crosswinds and road surface irregularities . In the present embodiment, the disturbances [1] and [2] are referred to as steady disturbances, and the disturbance [3] is referred to as transient disturbances.

  In the present embodiment, a plurality of disturbances having different frequency bands are estimated, and the output torque (drive current) of the motor 13 is corrected so as to suppress the estimated disturbance. At this time, the degree of disturbance suppression is changed according to the frequency band, and the degree of suppression is increased for low-frequency disturbances [1] and [2] (the degree of correction of the output torque of the motor 13 is increased). For the high-frequency disturbance [3], the suppression degree is reduced (the correction degree of the output torque of the motor 13 is reduced).

Next, processing executed by the disturbance compensation unit 105 will be described in detail.
FIG. 4 is a control block diagram showing the configuration of the disturbance compensation unit 105. In FIG. 4, the disturbance compensation unit 105 indicated by a one-dot chain line includes the target current calculation unit 102, the control voltage calculation unit 103, the drive current control unit 104, the motor 13 and the motor current sensor 13a of FIG. Description will be made assuming that the correction amount of the value I ^* is calculated.

If the transfer function of the steering system (relationship of the steering angle α with respect to the input of the steering torque) is Ps (s) and the transfer function of the vehicle system (relationship of the vehicle behavior with respect to the input of the steering angle α) is Pv (s), The characteristic P (s) is Ps (s) × Pv (s).
The input signal of this control system is a value obtained by adding the current converted value Is of the steering torque Ts corresponding to the steering input by the driver and the current target value I ^* corresponding to the steering input by the motor 13, and is unknown to this. A value obtained by adding the current converted value If of the disturbance Tf (actuator applied current) is an operation amount applied to the plant. The steering angle α becomes the control amount of this control system.

Here, the unknown disturbance Tf is a disturbance input to the vehicle including a steady disturbance Tc (disturbances [1] and [2] in FIG. 3) and a transient disturbance Td (disturbance [3] in FIG. 3).
The disturbance compensator 105 includes a disturbance estimator 105a that estimates disturbance in the low frequency band, a disturbance compensator 105b that compensates for disturbance in the low frequency band, a disturbance estimator 105c that estimates disturbance in the high frequency band, It comprises a disturbance compensation unit 105d that compensates for disturbances in the high frequency band.

That is, in this embodiment, two disturbances, a low frequency band disturbance compensation unit including the disturbance estimation unit 105a and the disturbance compensation unit 105b, and a high frequency band disturbance compensation unit including the disturbance estimation unit 105c and the disturbance compensation unit 105d. A compensation unit is provided.
The disturbance compensator 105 estimates the steady disturbance and the transient disturbance separately. Specifically, in each disturbance estimation unit, a signal obtained from the steering angle α as a controlled variable through the inverse characteristics of the plant and a low-pass filter, a current converted value Is and a current target value I ^{* of the} driver steering torque Ts ^. Is compared with the signal obtained via the low-pass filter, the current value corresponding to the disturbance (current converted value of the disturbance) is estimated. Here, the disturbance of an arbitrary frequency band can be estimated by changing the cutoff frequency of the low-pass filter for each disturbance estimation unit.

The cut-off frequency for estimating the disturbance in the low frequency band is defined by fc, and the low-pass filter is Hc (s) = 1 / {s / (2πfc) +1} ² . Then, a current-converted low frequency band disturbance (steady disturbance) is obtained from part A in the figure, which is the output of the disturbance estimation unit 105a. In the disturbance compensator 105b, a predetermined gain G1 is added to the steady-state disturbance current conversion value Ia, and a limiter is applied to feed back to the current target value I ^* , which is an input current.

Further, the cutoff frequency for estimating the disturbance in the high frequency band is defined by fd, and the low-pass filter is Hd (s) = 1 / {s / (2πfd) +1} ² . Then, from the portion B in the figure, which is the output of the disturbance estimation unit 105c, a current-converted low frequency band disturbance (steady disturbance) and a high frequency band disturbance (transient disturbance) are obtained. In the disturbance compensator 105d, a predetermined gain G2 is added to the current converted value Ib of the steady disturbance + transient disturbance, and further, a limiter is applied to feed back to the current target value I ^* that is the input current.
Here, it is assumed that G1 + G2 = 1.

(Operation)
Next, the operation of the first embodiment of the present invention will be described.
It is assumed that the vehicle is traveling and no disturbance is input to the vehicle. At this time, the unknown disturbance Tf = 0 in FIG. In this case, since the applied current of the actuator does not change with the current conversion value If of the unknown disturbance Tf, the sum of the driver steering torque current conversion value Is and the current target value I ^* is calculated as a low-pass filter Hc (s) ( Alternatively, the value passed through Hd (s)) is equal to the value passed through the steering angle α through the plant inverse characteristic 1 / P (s) and the low-pass filter Hc (s) (or Hd (s)). Therefore, the disturbance current conversion values Ia and Ib obtained from the A part and the B part in FIG. 4 are both 0, and the correction amount of the current target value I ^* is 0. Thereby, normal steering is performed without performing steering control for suppressing disturbance input to the vehicle.

Actually, low-frequency disturbances are steadily input to a running vehicle due to a difference in vehicle left and right, a difference in tire conicity, a road surface cant, and the like. When such a steady disturbance is input to the vehicle, unknown disturbance Tf = steady disturbance Tc in FIG. Since the transient disturbance Td = 0, the disturbance current conversion values Ia and Ib obtained from the A part and the B part in FIG. 4 are both the current conversion values of the steady disturbance Tc. A value obtained by multiplying the current conversion values Ia and Ib by the gains G1 and G2 is a correction amount of the current target value I ^* .

Since in this embodiment a G1 + G2 = 1, the correction amount of the current target value I ^* corresponds to a value obtained by multiplying the gain 1 in the current conversion value of steady disturbance Tc. That is, the current target value I ^* is corrected with the current converted value of the steady disturbance Tc, and all the steady disturbance Tc is suppressed.
In this way, by suppressing all the steady disturbances Tc, it is possible to reliably suppress the steering torque change due to the vehicle-induced single flow and the road surface cant change. As a result, it is possible to reduce the driving load such that the driver does not need to maintain a predetermined steering angle in order to maintain traveling in the center of the vehicle lane.

Next, a case where a high-frequency disturbance due to cross wind or road surface irregularity is input to the host vehicle will be described.
FIG. 5 is a diagram showing a time series transition of disturbance input. In FIG. 5, a low-frequency disturbance (disturbance [1]) due to vehicle left-right difference or tire conicity left-right difference is indicated by a broken line, and a very low-frequency disturbance (disturbance [2]) generated by a road surface cant or the like. Is indicated by an alternate long and short dash line, and a high-frequency disturbance (disturbance [3]) due to crosswinds or road surface irregularities is indicated by an alternate long and two short dashes line. Further, the total disturbance (disturbance [1] + [2] + [3]) input to the vehicle is indicated by a solid line.

It is assumed that the vehicle passes through the tunnel exit from a state where the vehicle travels straight through the tunnel and receives a strong crosswind. In this case, a high-frequency disturbance as shown by a two-dot chain line is input to the vehicle at time t1 in FIG. At this time, the disturbance compensator 105 in FIG. 4 obtains the current conversion value Ia of the disturbance [1] which is a constant disturbance and the low-frequency disturbance [2] from the A part, and the disturbances [1] to [3] from the B part. ] Is obtained. Here, the disturbance current conversion value Ib obtained from the part B is a disturbance current conversion value in which a very high frequency component of the cross wind is filtered by the cut-off frequency fd in the high frequency band. The sum of values obtained by multiplying these current conversion values Ia and Ib by gains G1 and G2, respectively, is the correction amount of the current target value I ^* .

FIG. 6 is a diagram for explaining the effect of the present embodiment. In FIG. 6, the thin line is the total disturbance input to the vehicle, the broken line is the disturbance compensation amount in the low frequency band, the two-dot chain line is the disturbance compensation amount in the high frequency band, and the thick solid line is the disturbance compensation amount in the low frequency band and the high frequency band. Is the total compensation amount obtained by adding the disturbance compensation amount.
In the present embodiment, since the sum of gains (G1 + G2) is 1, the disturbances [1] and [2] in the low frequency band are completely corrected as shown by the thick solid line in FIG. Further, the disturbance [3] in the high frequency band is not corrected entirely, but is corrected while leaving a part (A part in FIG. 6). That is, the current target value I ^* is corrected with a correction degree according to the disturbance frequency band, and the correction degree decreases as the disturbance frequency band increases.

In this way, when a high-frequency disturbance such as a side wind disturbance is input to the vehicle, it is corrected by leaving a part of the disturbance, so the driver corrects the change in the vehicle behavior accompanying the input of the side wind disturbance. When steering, the steering operation feels heavy. As a result, an increase in the steering operation speed can be suppressed, and the stability of the vehicle behavior can be improved.
By the way, a disturbance observer is used to separate low-frequency road gradient disturbances and high-frequency side wind disturbances and estimate them, and steering assist torque is given so as to completely suppress the influence of the side wind disturbance on the steering. In such a case, the operation is as follows.

7 and 8 are diagrams for explaining the operation when the influence of only the side wind disturbance is completely suppressed.
When the steering assist torque is applied so as to completely suppress the influence on the steering by the input of the cross wind disturbance at the time of disturbance input, as shown in FIG.
However, when the driver detects the movement of the vehicle sensitively during crosswind disturbance input and corrective steering is performed against the disturbance input, the direction in which the steering assist torque is applied coincides with the direction of the corrective steering by the driver. Therefore, the steering operation is facilitated. As a result, as shown in FIG. 7B, the vehicle behavior becomes larger than intended by the driver, which may give the driver a sense of discomfort.

Moreover, since the process which suppresses the influence on the steering by the input of road surface gradient disturbance is not performed, as shown by the broken line of FIG. 8, there is a possibility that a single flow due to the road surface gradient occurs. In this case, as shown by the solid line in FIG. 8, in order to maintain the vehicle traveling straight, the driver needs to maintain a predetermined steering angle, which increases the driving load.
In contrast, in this embodiment, a plurality of disturbances having different frequency bands are estimated, and disturbances in the low frequency band are completely corrected by increasing the degree of suppression, while disturbances in the high frequency band are reduced in the degree of suppression. Correct some of them. In other words, the low-frequency band disturbance is less likely to be subjected to corrective steering by the driver with respect to the vehicle behavior at the time of disturbance input. The degree of suppression is reduced for band disturbance.

Therefore, it is possible to reliably prevent a single flow or the like caused by a low-frequency disturbance input, and to suppress the synchronization between the correction steering by the driver and the steering by the control at the time of high-frequency disturbance input, thereby stabilizing the vehicle behavior. Can be improved.
In the disturbance compensation unit 105, a limiter is provided for each of the disturbance compensation amount (current conversion value Ia) in the low frequency band and the disturbance compensation amount (current conversion value Ib) in the high frequency band. As a result, the disturbance exceeding the limit value is not suppressed.

In this embodiment, since the limiter is provided for the disturbance compensation amount in the high frequency band, if a large transient disturbance is input to the vehicle, the limiter does not suppress disturbance exceeding the limit value. Thus, it is possible to reliably transmit that a disturbance is input to the driver.
At this time, all transient disturbances smaller than the limit value are to be suppressed. Therefore, if the limit value is set to a value that suppresses all small disturbances that require almost no correction steering at the time of disturbance input, the vehicle can be effectively used. It is possible to stabilize the behavior.

In addition, if the limit value is set so that the weight of the steering operation with the limiter applied is acceptable to the driver, the deterioration of the steering feeling caused by the excessive increase of the steering torque is suppressed. can do.
Furthermore, when a large transient disturbance is input to the vehicle, the amount of disturbance compensation is not increased following the change in the disturbance, so that the predetermined steering weight is maintained in proportion to the magnitude of the disturbance. And a stable steering feeling can be obtained.

Since the vehicle behavior and the steering weight at the time of disturbance input vary depending on the specifications of the vehicle and the specifications of the steering system, it is desirable to set the limit value experimentally for each vehicle type.
In this embodiment, a limiter is also provided for the amount of disturbance compensation in the low frequency band.
The steady disturbance caused by the vehicle is constant in a specific vehicle, but becomes a value within a predetermined range due to variations in production. Also, the disturbance caused by the road surface cant is a value within a predetermined range for a straight road (for example, between 1 and 3 on a highway in North America). Therefore, if the limit value is set from these two values, the steady disturbance caused by the vehicle and the disturbance caused by the road surface cant are completely suppressed.

By the way, when a puncture or the like occurs, for example, a disturbance exceeding the limit value is input to the vehicle, and this is not suppressed. However, in such a case, the steering torque change is transmitted to the driver, which is effective because the driver can notice the occurrence of puncture.
In addition, since the disturbance caused by the road surface cant on the curved road is larger than the disturbance caused by the road surface cant on the straight road, in this case, the disturbance is not an object to be suppressed, and the steering torque change is transmitted to the driver. However, since the steering torque is generated during the turn, the amount of change is small and not a problem level.

  In the present embodiment, the motor 13 constitutes an actuator, and the target torque calculation unit 101, the target current calculation unit 102, the control voltage calculation unit 103, and the drive current control unit 104 constitute a control unit. Further, the encoder 15 constitutes a steering state quantity detection means, the disturbance estimation units 105a and 105c constitute a disturbance estimation means, and the disturbance compensation units 105b and 105d constitute a disturbance compensation means.

(Effects of the first embodiment)
(1) A frequency input to the vehicle by a plurality of disturbance estimation means based on the steering input by the driver, the steering input by the actuator, and the actual steering state quantity, which is detected by the steering state quantity detection means. Estimate multiple disturbances in different bands. Then, the output torque of the actuator is corrected with a correction degree corresponding to the frequency band of the disturbance so as to suppress each disturbance estimated by the disturbance estimating means.

Therefore, the degree of suppression can be changed in accordance with the frequency band of the disturbance, such as suppressing all disturbances in the low frequency band and suppressing a part of the disturbance in the high frequency band. As a result, it is possible to reliably suppress the influence of disturbance inputs in the low frequency band such as a single flow caused by the vehicle and a steering torque change accompanying a change in road surface cant.
In addition, by correcting a part of the disturbance input in a high frequency band such as a crosswind, the disturbance input can be transmitted to the driver, and the driver corrects the steering to correct the vehicle behavior associated with the disturbance input. In this case, since the operation speed of the correction steering is reduced when the steering wheel feels heavy, the synchronization of the steering by the driver and the steering by the control can be suppressed, and the stability of the vehicle behavior can be improved.

(2) A disturbance estimation means, in which a steering input by a driver and a steering input by an actuator are control inputs, and the actual steering angle is a control amount, a value obtained by passing the control input through a low-pass filter, and the control amount Since the disturbance is estimated based on the difference between the inverse characteristic of the model and the value passed through the low-pass filter, the disturbance input to the vehicle can be appropriately estimated.
Further, since the cutoff frequency of the low-pass filter is set to a different value for each disturbance estimation means, the disturbance input to the vehicle can be estimated for each arbitrary frequency band.

(3) The degree of correction of the output torque of the actuator is reduced as the disturbance has a higher frequency band such as a crosswind disturbance. Specifically, the total disturbance compensation amount is determined by adding a value obtained by adding a predetermined gain to the current conversion value of the steady disturbance and a value obtained by adding the predetermined gain to the current conversion value of the steady disturbance + transient disturbance. Suppose the sum of each gain is 1.
Therefore, it is possible to suppress all disturbances that are less likely to be corrected by the driver when a disturbance is input, and to leave more disturbances that are likely to be corrected. As a result, it is possible to improve the stability of the vehicle behavior by suppressing the synchronization between the correction steering by the driver and the steering control for suppressing the disturbance.

  (4) Since a limit value is provided for the disturbance compensation amount in the high frequency band, it is possible to prevent disturbance suppression exceeding the limit value. Therefore, it is possible to reliably transmit the disturbance input to the driver. In addition, since the amount of compensation is not increased following the magnitude of the disturbance input to the vehicle, the predetermined steering wheel weight can be maintained, and the vehicle behavior during the correction steering can be stabilized.

  (5) Since the output torque of the actuator is controlled so as to suppress the disturbance with the degree of suppression according to the possibility that the driver will perform the correction steering with respect to the vehicle behavior at the time of disturbance input, the correction by the driver Suppresses all low-frequency disturbances that are unlikely to be steered, and partially suppresses high-frequency disturbances that are likely to be corrected by the driver The degree of suppression can be changed according to the frequency band of disturbance. As a result, stable vehicle behavior can be maintained even when corrective steering is performed by the driver during disturbance input.

  (6) A frequency that is input to the vehicle by a plurality of disturbance estimation means based on the steering input by the driver, the steering input by the actuator, and the actual steering state quantity, by detecting the steering state quantity by the steering state quantity detection means. Estimate multiple disturbances in different bands. Then, the output torque of the actuator is corrected with a correction degree corresponding to the frequency band of the disturbance so as to suppress each disturbance estimated by the disturbance estimating means. Therefore, since the degree of suppression can be changed according to the frequency band of the disturbance, it is possible to provide an automobile capable of maintaining a stable vehicle behavior when the disturbance is input.

  (7) Based on the steering input by the driver, the steering input by the actuator, and the actual steering state quantity, a plurality of disturbances having different frequency bands input to the vehicle are estimated, and the disturbances are suppressed. The output torque of the actuator is corrected with a correction degree corresponding to the frequency band of the disturbance. Therefore, since the degree of suppression can be changed according to the frequency band of disturbance, stable vehicle behavior can be maintained at the time of disturbance input.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.
(Constitution)
In the second embodiment, the total disturbance compensation amount is the sum of the steady disturbance compensation amount and the steady disturbance + transient disturbance compensation amount in the first embodiment described above, whereas the steady disturbance disturbance amount. The compensation amount and the compensation amount of the transient disturbance are calculated, and the sum of both is made the total disturbance compensation amount.

  FIG. 9 is a control block diagram illustrating a configuration of the disturbance compensation unit 105 according to the second embodiment. In the disturbance compensator 105 of the present embodiment, in the disturbance compensator 105 of the first embodiment shown in FIG. 4, the disturbance compensator 105d obtains the current conversion value Ia obtained from the disturbance estimator 105a and the disturbance estimator 105c. 4 has the same configuration as the disturbance compensation unit 105 in FIG. 4 except that the disturbance compensation amount in the high frequency band is calculated based on the difference from the current conversion value Ib obtained from the The explanation will focus on the part.

The current conversion value Ia of the steady disturbance is obtained from the A part of FIG. 9, and the current conversion value Ib of the steady disturbance + transient disturbance is obtained from the B part of FIG. 9, so that the current conversion value Ia and the current conversion value Ib From this difference, a current equivalent value Ic (= Ib−Ia) of the transient disturbance is obtained (C portion in FIG. 9).
In the disturbance compensator 105d, a predetermined gain G2 is added to the current converted value Ic of the transient disturbance, and further, a limiter is applied to feed back to the current target value I ^* that is the input current.
Here, the gain G1 of the disturbance compensator in the low frequency band is set to 1, and the gain G2 of the disturbance compensator in the high frequency band is set to a value smaller than 1.

(Operation)
Next, the operation of the second exemplary embodiment of the present invention will be described.
It is assumed that the vehicle passes through the tunnel exit from a state where the vehicle travels straight through the tunnel and receives a strong crosswind. In this case, a high-frequency disturbance as shown by a two-dot chain line is input to the vehicle at time t1 in FIG. At this time, the disturbance compensator 105 in FIG. 9 obtains the current conversion value Ia of the disturbance [1] which is a constant disturbance and the low-frequency disturbance [2] from the A part, and the disturbances [1] to [3] from the B part. ] Is obtained. In addition, the current conversion value Ic (= Ib−Ia) of the transient disturbance [3] is obtained from the C part.
The sum of the value obtained by multiplying the current conversion value Ia by the gain G1 and the value obtained by multiplying the current conversion value Ic by the gain G2 is the correction amount of the current target value I ^* .

FIG. 10 is a diagram for explaining the effect of the present embodiment. In FIG. 10, the thin line is the total disturbance input to the vehicle, the broken line is the disturbance compensation amount in the low frequency band, the two-dot chain line is the disturbance compensation amount in the high frequency band, and the thick solid line is the disturbance compensation amount in the low frequency band and the high frequency band. Is the total compensation amount obtained by adding the disturbance compensation amount.
In the present embodiment, the gain G1 is set to 1 and the gain G2 is set to a value smaller than 1, so that the disturbances [1] and [2] in the low frequency band are completely corrected as shown by the thick solid line in FIG. become. Further, the disturbance [3] in the high frequency band is not corrected entirely, but is corrected while leaving a part.

  As described above, when a disturbance in a high frequency band such as a crosswind disturbance is input to the vehicle, the correction is made by leaving a part of the disturbance, so that the vehicle accompanying the input of the crosswind disturbance as in the first embodiment described above. When the driver steers to correct the behavior change, the steering operation feels heavy. As a result, an increase in the steering operation speed can be suppressed, and the stability of the vehicle behavior can be improved.

(Effect of 2nd Embodiment)
(1) The degree of correction is reduced as the disturbance has a higher frequency band such as crosswind. Specifically, the total disturbance compensation amount is determined by adding a value obtained by integrating gain 1 to the current converted value of steady disturbance and a value obtained by adding a gain smaller than 1 to the current converted value of transient disturbance.
Therefore, it is possible to suppress all small disturbances that do not require correction steering for the vehicle behavior at the time of disturbance input, and to leave some large disturbances that require correction steering. As a result, it is possible to suppress the synchronization between the correction steering operation by the driver and the steering torque control for suppressing the disturbance, thereby improving the stability of the vehicle behavior.

(Application examples)
In the second embodiment, from the difference between the disturbance estimated value in the low frequency band (current converted value Ia for steady disturbance) and the disturbance estimated value in the high frequency band (steady disturbance + converted current value Ib for transient disturbance). Although the case where the current converted value Ic of only the transient disturbance is calculated has been described, the current converted value Ic of only the transient disturbance can also be extracted by applying a bandpass filter to the disturbance estimated value in the high frequency band. Also in this case, since the steady disturbance and the transient disturbance can be estimated individually, the correction degree can be changed according to the frequency band of the disturbance.

(Third embodiment)
Next, a third embodiment of the present invention will be described.
(Constitution)
In the third embodiment, in the first and second embodiments described above, a damping compensation unit that performs damping control for disturbance input in a high frequency band is added.
FIG. 11 is a control block diagram illustrating a configuration of the disturbance compensation unit 105 in the third embodiment. The disturbance compensator 105 of this embodiment has the same configuration as the disturbance compensator 105 of the first embodiment shown in FIG. 4, and is a value obtained by integrating a predetermined gain (damping coefficient) G3 to the steering angular velocity β. A damping compensation unit 200 that performs damping control for disturbance input in a high frequency band is added by negatively feeding back (damping compensation amount) with respect to the current target value I ^* . Then, based on the disturbance compensation amount of the disturbance compensation unit 105 and the damping compensation amount of the damping compensation unit 200, the current target value I ^* is corrected.

The damping compensation unit 200 calculates the gain G3 based on the steering angular velocity calculation unit 201 that calculates the steering angular velocity β based on the steering angle α, and the disturbance estimated value (steady disturbance + transient disturbance current conversion value Ib) in the high frequency band. And a gain setting unit 202 to be set.
The steering angular velocity calculation unit 201 calculates the steering angular velocity β by differentiating the steering angle α with respect to time. It is also possible to detect the steering angular velocity β using a tacho generator or the like that directly measures the rotational speed.
The gain setting unit 202 sets the gain G3 with reference to a previously stored gain setting map based on the estimated disturbance value (steady disturbance + transient disturbance current conversion value Ib) in the high frequency band.

In this gain setting map, the horizontal axis represents the current conversion value Ib, and the vertical axis represents the gain G3. When the current conversion value Ib is equal to or greater than the predetermined value −TH and is equal to or less than TH, G3 = 0 is set. It has become. In the region where the current conversion value Ib is larger than TH, the gain G3 also increases proportionally as the current conversion value Ib increases, and in the region where the current conversion value Ib is smaller than -TH, the current conversion value Ib decreases. Along with this, the gain G3 also decreases proportionally. The gain G3 has an upper limit value and a lower limit value.
Then, the damping compensation unit 200 multiplies the steering angular velocity β calculated by the steering angular velocity calculation unit 201 by the gain G3 set by the gain setting unit 202, and negatively feeds back this with respect to the current target value I ^* . Thus, the current target value I ^* is corrected.

(Operation)
Next, the operation of the third embodiment of the present invention will be described.
It is assumed that the vehicle passes through the tunnel exit from a state where the vehicle travels straight through the tunnel and receives a strong crosswind. In this case, a high-frequency disturbance as shown by a two-dot chain line is input to the vehicle at time t1 in FIG. At this time, the disturbance compensator 105 in FIG. 11 obtains the current conversion value Ia of the disturbance [1] which is a constant disturbance and the low-frequency disturbance [2] from the A part, and the disturbances [1] to [3] from the B part. ] Is obtained. The sum of values obtained by multiplying these current conversion values Ia and Ib by gains G1 and G2 is the total disturbance compensation amount.

When a side wind disturbance is input, steering torque control is performed to partially suppress the side wind disturbance by the above disturbance compensation amount. In general, a delay is set in the control to ensure the stability of the control. Thus, the disturbance is not suppressed instantaneously, and the vehicle behavior due to the disturbance input occurs. At this time, it is assumed that the driver performs corrective and quick correction steering.
When the high-frequency disturbance input to the vehicle is relatively large and Ib> TH, the gain setting unit 202 of the damping compensation unit 200 sets the gain G3 to a relatively large value. As a result, the damping compensation amount obtained by multiplying the steering angular velocity β and the gain G3 also becomes a large value.

Accordingly, the correction amount of the current target value I ^* when the corrected target current value I ^* with damping compensation amount in addition to the disturbance compensation amount, the current target value when the corrected target current value I ^* only disturbance compensation amount Compared with the correction amount of I ^* , it is reduced by the amount of damping compensation.
That is, when disturbance in the high frequency band is input, when the driver performs large correction steering at a high steering speed, damping control is performed in which the steering speed is suppressed and the steering operation becomes heavy. As a result, excessive correction steering and excessive vehicle behavior by the driver are suppressed.

Further, since the gain setting unit 202 provides the upper limit value and the lower limit value for the gain G3, it is possible to prevent the damping compensation amount from becoming too large even when the steering angular velocity β is very high. As a result, it is possible to prevent the steering torque from becoming too heavy due to the damping control.
In the present embodiment, the damping compensation unit 200 constitutes damping compensation means.

(Effect of the third embodiment)
(1) Based on the disturbance in the high frequency band and the steering angular velocity among the disturbances input to the vehicle, the output torque of the actuator is corrected so as to perform damping control for the disturbance input in the high frequency band. Therefore, since the steering behavior when a disturbance in the high frequency band is input is suppressed, a stable vehicle behavior can be realized.

(2) The damping coefficient is set to be larger as the disturbance in the high frequency band is larger. In addition, a limit value is set for this damping coefficient.
Therefore, the larger the disturbance in the high frequency band, the larger the damping compensation amount can be set. The greater the disturbance, the greater the vehicle behavior at the time of disturbance input, and the driver's corrective steering tends to increase, so by setting the damping compensation amount large in this way, the steering behavior is suppressed and more stable Vehicle behavior can be realized.
Also, by providing a limit value for the damping coefficient, it is possible to prevent the amount of damping compensation from becoming too large, so that it is possible to prevent the steering torque from becoming too heavy due to damping control.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.
(Constitution)
In the fourth embodiment, in the first to third embodiments described above, the disturbance compensator in the high frequency band adds a predetermined gain to the estimated disturbance value, and then replaces the normal limiter with a rate limiter. It's something that you want to call.
FIG. 12 is a control block diagram illustrating a configuration of the disturbance compensation unit 105 according to the fourth embodiment. In the disturbance compensator 105 of this embodiment, in the disturbance compensator 105 of the first embodiment shown in FIG. 4, the disturbance compensator 105d adds the gain G2 to the current conversion value Ic obtained from the disturbance estimator 105c. after, except that it has to be fed back to the current target value I ^* to multiplied by the rate limiter as a disturbance compensation amount of the high frequency band, it has the same structure as the disturbance compensation module 105 of FIG. 4, The description will focus on the different parts of the process.
The rate limiter is for limiting the rate of change of the disturbance compensation amount, and the limit value of the rate limiter is lower than the cutoff frequency fd of the low-pass filter Hd (s) that determines the characteristics of the high frequency band. Set to value.

(Operation)
Next, the operation of the fourth embodiment of the present invention will be described.
It is assumed that the vehicle passes through the tunnel exit from a state where the vehicle travels straight through the tunnel and receives a strong crosswind. In this case, a high-frequency disturbance as shown by a two-dot chain line is input to the vehicle at time t1 in FIG. At this time, the disturbance compensator 105 in FIG. 12 obtains the current conversion value Ia of the disturbance [1] which is a constant disturbance and the low-frequency disturbance [2] from the A part, and the disturbances [1] to [3] from the B part. ] Is obtained. The sum of values obtained by multiplying these current conversion values Ia and Ib by gains G1 and G2 is the total disturbance compensation amount.
Here, a rate limiter is applied to the disturbance compensation amount in the high frequency band, and the change speed of the disturbance compensation amount in the high frequency band is limited, so that fluctuations in the disturbance compensation amount are suppressed. .
That is, it is possible to suppress a sudden change in the amount of disturbance compensation that cannot be shaped only by the frequency characteristics by the rate limiter.

(Effect of the fourth embodiment)
(1) A limit is set on the change speed of the correction amount of the output torque of the actuator. Therefore, since a rapid change in the correction amount can be suppressed, a sudden change in steering torque accompanying a sudden change in the correction amount can be suppressed.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described.
(Constitution)
In the fifth embodiment, the gain G2 of the disturbance compensator in the high frequency band is set based on the steering input by the driver and the magnitude of the disturbance in the high frequency band in the first to fourth embodiments described above. It is what you do.
FIG. 13 is a control block diagram illustrating a configuration of the disturbance compensation unit 105 according to the fifth embodiment. The disturbance compensator 105 of the present embodiment is the same as the disturbance compensator 105 of the first embodiment shown in FIG. 4 except that the gain G2 of the disturbance compensator in the high frequency band is set to the steering input by the driver and the high frequency band. Except for the calculation based on the magnitude of the disturbance, the configuration is the same as that of the disturbance compensation unit 105 in FIG.

The gain G2 is set with reference to the gain calculation map based on the current converted value Is of the driver steering torque Ts and the current converted value Ib of steady disturbance + transient disturbance obtained from the disturbance estimating unit in the high frequency band.
The gain calculation map shown in FIG. 13 is a map when the current conversion value Ib is a positive value. The horizontal axis represents the current conversion value Is of the driver steering torque Ts, the vertical axis represents the gain G2, and the current conversion value Is is The gain G2 is set to a constant value (for example, 1) in the range from 0 to the steady disturbance + transient disturbance current conversion value Ib, and the gain G2 increases from the above constant value to 0 as the current conversion value Is becomes larger than the current conversion value Ib. Is set proportionally smaller. Further, in a region where the current conversion value Is is smaller than 0, the gain G2 is set proportionally smaller from the constant value to 0 as the current conversion value Is is smaller.

  Further, when the current conversion value Ib is a negative value, the gain G2 is set to a constant value (for example, 1) in the region where the current conversion value Is is from the steady disturbance + transient disturbance current conversion value Ib to 0, The gain G2 is set proportionally smaller from the constant value to 0 as the current conversion value Is becomes larger than 0. In a region where the current conversion value Is is smaller than the current conversion value Ib, the gain G2 becomes smaller as the current conversion value Is decreases. From a certain value to 0, it is set proportionally smaller.

(Operation)
Next, a fifth embodiment of the present invention will be described.
It is assumed that the vehicle passes through the tunnel exit from a state where the vehicle travels straight through the tunnel and receives a strong crosswind. In this case, a high-frequency disturbance as shown by a two-dot chain line is input to the vehicle at time t1 in FIG. At this time, the disturbance compensator 105 in FIG. 13 obtains the current conversion value Ia of the disturbance [1] which is a constant disturbance and the low-frequency disturbance [2] from the A part, and the disturbances [1] to [3] from the B part. ] Is obtained. The sum of values obtained by multiplying these current conversion values Ia and Ib by gains G1 and G2 is the total disturbance compensation amount.

Here, it is assumed that the driver is letting go when the side wind disturbance is input. In this case, since the driver steering torque Ts = 0, the current converted value Is = 0 of the driver steering torque Ts is obtained. Therefore, the gain G2 = 1 is set by the gain calculation map. Since G1 + G2 = 1, G1 = 0.
Thereby, the compensation amount of the steady disturbance output from the disturbance compensator in the low frequency band becomes 0, and the target current value I ^* is obtained only by the compensation amount of the steady disturbance + transient disturbance output from the disturbance compensator in the high frequency band. It is corrected. At this time, since the gain G2 = 1, both the steady disturbance and the transient disturbance are corrected, and the vehicle is not affected by the disturbance input. Therefore, the vehicle automatically travels straight.

FIG. 14 is a diagram illustrating a relationship between the disturbance Tb in the high frequency band and the driver steering torque Ts. As described above, the relationship between the disturbance Tb and the steering torque Ts when the driver is driving by hand at the time of disturbance input is as shown by the straight line shown in FIG.
On the other hand, the driver does not actively steer when a disturbance is input, and the steering wheel is moved lightly according to the disturbance input to the vehicle with a light hand on the steering wheel (lightly steered) Then, since the disturbance Tb in the high frequency band and the driver steering torque Ts become equal, the relationship between the disturbance Tb in the high frequency band and the driver steering torque Ts becomes a straight line shown in (2) in the figure. In this case as well, the gain G2 = 1 as in the case where the driver is letting go when the disturbance is input, so that both the steady disturbance and the transient disturbance are corrected, and the vehicle is affected by the disturbance input. I will not receive it.

  Further, when the driver's steering state is an intermediate state between letting go and light steering at the time of disturbance input, the relationship between the disturbance Tb in the high frequency band and the driver steering torque Ts is the straight line (1) and the straight line in FIG. It is in the area (3) sandwiched between (2). Even in this region (3), since the gain G2 = 1, both the steady disturbance and the transient disturbance are corrected, and the vehicle is not affected by the disturbance input.

  On the other hand, at the time of disturbance input, if the driver is actively steering in the same direction as the disturbance input and the driver steering torque Ts is greater than the disturbance Tb, the relationship between the disturbance Tb in the high frequency band and the driver steering torque Ts is The region (4) is sandwiched between the straight line (2) and the straight line Tb = 0 in FIG. In this region (4), since Ts> Tb, that is, Is> Ib, the gain G2 is set to a value smaller than 1 by the gain calculation map. Accordingly, all of the steady disturbances are corrected, but the transient disturbances are corrected by leaving a part (transient disturbance correction amount is reduced).

Thus, when the driver is steering larger than the disturbance in the disturbance direction at the time of disturbance input, the disturbance compensation amount in the high frequency band is reduced, so that the driver performs steering torque control for disturbance suppression. A sense of incongruity caused by the promotion of steering can be suppressed.
Further, if the driver is steering in the opposite direction to the disturbance input (direction against the disturbance input) at the time of disturbance input, the signs of the driver steering torque Ts and the disturbance Tb are reversed, and therefore the disturbance in the frequency band. The relationship between Tb and driver steering torque Ts is in the region (5) in FIG. In this region (5), the gain G2 is set to a value smaller than 1 by the gain calculation map. Accordingly, all of the steady disturbances are corrected, but the transient disturbances are corrected by leaving a part (transient disturbance correction amount is reduced).

In this way, when the driver is steering in the direction opposite to the disturbance when the disturbance is input, the disturbance compensation amount in the high frequency band is reduced, so that the steering torque control for disturbance suppression and the steering by the driver are performed. Can suppress a sense of incongruity caused by interference.
Furthermore, the greater the steering by the driver (the larger | Is | is greater than | Ib |), the smaller the amount of disturbance compensation in the high frequency band, so the driver's uncomfortable feeling can be further suppressed.

(Effect of 5th Embodiment)
(1) The disturbance compensation means corrects the output torque of the actuator for the disturbance in the high frequency band based on the disturbance in the high frequency band among the disturbances input to the vehicle and the steering torque generated by the driver's steering. When the driver makes steering input, such as when the driver reacts to sudden disturbance input such as crosswinds and corrects steering, or when the driver actively steers in the same direction as the disturbance input. The degree of correction of the output torque of the actuator can be reduced. As a result, since the synchronization and interference between the steering torque control for suppressing disturbance and the steering by the driver are suppressed, the steering performance can be improved and a more stable vehicle behavior can be realized.

(Application examples)
In each of the above embodiments, the case where the present invention is applied to a vehicle equipped with an electric power steering system has been described. However, the present invention can also be applied to a vehicle equipped with a steer-by-wire system.
FIG. 15 is a schematic configuration diagram when the present invention is applied to a vehicle equipped with a steer-by-wire system. In this vehicle, a reaction force controller 30 is provided instead of the EPS controller 20 in the vehicle of FIG. It is assumed that a device for rolling the steered wheels is provided separately.

  The reaction force controller 30 receives detection signals from various sensors, and calculates the drive current of the motor 13 based on these detection signals (steering torque, encoder signal, vehicle speed, etc.). Then, the motor 13 is controlled and driven based on the calculated drive current while referring to the motor current detected by a motor current sensor (not shown) and the motor rotation angle detected by the encoder 15.

  The specific configuration of the reaction force controller 30 is the same as the configuration of the EPS controller 20 in the first to fifth embodiments shown in FIG. The target torque calculation unit 101 of the reaction force controller 30 generates a motor reaction force substantially proportional to the steering angle (encoder signal) to control the steering reaction force of the driver, and the inertia of the motor. The basic torque command value Tp is calculated by an inertia compensation assisting unit that compensates, a damping assisting unit that ensures damping of the steering system, and a steering wheel return assisting unit that improves steering wheel return. Yes.

The disturbance compensation unit 105 of the EPS controller 20 uses the plant characteristic P (s) as the steering system characteristic Ps (s) × the vehicle system characteristic Pv (s), whereas the reaction force controller 30 provides disturbance compensation. The unit 105 uses only the steering system characteristic Ps (s) as the plant characteristic P (s), and takes into account only the inertia and viscosity of the steering system or other friction.
Further, the present invention can also be applied to a vehicle equipped with a motor pump type power steering system.
As described above, even when the present invention is applied to a vehicle equipped with a steer-by-wire system or a motor pump type power steering system, the first to fifth aspects where the present invention is applied to a vehicle equipped with an electric power steering system. The same effect as the embodiment can be obtained.

In each of the above-described embodiments, the disturbance compensation unit 105 uses a value obtained by adding the current converted value Is of the driver steering torque Ts and the current target value I ^* as an input signal, and the control system using the steering angle α as a controlled variable. However, as shown in FIG. 16, the steering angular velocity β can also be used as a control amount. In this case, the same effect as that obtained when the steering angle α is controlled can be obtained.
In each of the above embodiments, the case where two disturbance compensators, that is, a disturbance compensator in a low frequency band and a disturbance compensator in a high frequency band, is described. However, three or more disturbance compensators having different frequency bands are provided. Can also be provided. This makes it possible to set the correction degree more appropriately according to the type of disturbance input to the vehicle.

It is a schematic structure figure showing a steering control device in an embodiment of the present invention. It is a block diagram which shows the structure of an EPS controller. It is the frequency distribution of the disturbance input into a vehicle. It is a control block diagram of the disturbance compensation part in 1st Embodiment. It is a time series transition of disturbance input to the vehicle. It is a figure explaining the effect of a 1st embodiment. It is a figure explaining the vehicle behavior at the time of crosswind input. It is a figure explaining the vehicle behavior by a road surface gradient. It is a control block diagram of the disturbance compensation part in 2nd Embodiment. It is a figure explaining the effect of 2nd Embodiment. It is a control block diagram of the disturbance compensation part in 3rd Embodiment. It is a control block diagram of the disturbance compensation part in 4th Embodiment. It is a control block diagram of the disturbance compensation part in 5th Embodiment. It is a figure explaining the relationship between driver steering torque and the disturbance of a high frequency band. It is a schematic block diagram at the time of applying this invention to the vehicle carrying a steer-by-wire system. It is a control block diagram which shows another example of a disturbance compensation part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 3 Rack and pinion type gear mechanism 6,7 Steering wheel 11 Torque sensor 13 Motor 15 Encoder 16 Vehicle speed sensor 20 EPS controller 101 Target torque calculation part 102 Target current calculation part 103 Control voltage calculation part 104 Drive current control Part 105 Disturbance compensation part 106 Target torque correction part

Claims (11)

A steering control device comprising an actuator capable of adjusting a steering torque and a control means for controlling an output torque of the actuator,
Steering state quantity detection means for detecting at least one of a steering angle and a steering angular velocity as a steering state quantity, a steering input by a driver, a steering input by the actuator, and an actual steering state quantity detected by the steering state quantity detection means And a plurality of disturbance estimation means for estimating a plurality of disturbances having different frequency bands input to the vehicle, and the output torque of the actuator is controlled so as to suppress each disturbance estimated by the disturbance estimation means. A steering control device comprising: a plurality of disturbance compensation means for correcting at a correction degree according to the frequency band of   The disturbance estimation means is a model in which a steering input by a driver and a steering input by the actuator are control inputs, and an actual steering state amount is a control amount, and a value obtained by passing the control input through a low-pass filter and the control amount A disturbance is estimated based on a difference between an inverse characteristic of the model and a value passed through the low-pass filter, and the cutoff frequency of the low-pass filter is different for each disturbance estimation unit. The steering control device according to claim 1.   The steering control device according to claim 1, wherein the disturbance compensation unit reduces the correction degree as the frequency band of the disturbance estimated by the disturbance estimation unit is higher.   Based on the disturbance in the high frequency band among the disturbances estimated by the disturbance estimating means and the steering angular velocity detected by the steering state quantity detecting means, the damping control for the disturbance input in the high frequency band is performed. The steering control device according to any one of claims 1 to 3, further comprising damping compensation means for correcting an output torque of the actuator.   The damping compensation means sets the correction amount of the output torque of the actuator by multiplying the steering angular velocity by a predetermined damping coefficient, sets the damping coefficient to be larger as the disturbance in the high frequency band is larger, and the damping The steering control device according to claim 4, wherein a limit value is provided for the coefficient.   The steering control device according to claim 1, wherein the disturbance compensation unit provides a limit value for a correction amount of an output torque of the actuator.   The steering control device according to any one of claims 1 to 6, wherein the disturbance compensation unit provides a limit value for a change speed of a correction amount of an output torque of the actuator.   The disturbance compensation means determines the degree of correction of the output torque of the actuator for the disturbance in the high frequency band based on the disturbance in the high frequency band of the disturbance estimated by the disturbance estimation means and the steering input by the driver. The steering control device according to claim 1, wherein the steering control device is changed. A steering control device comprising an actuator capable of adjusting a steering torque and a control means for controlling an output torque of the actuator,
A steering control means is provided for controlling the output torque of the actuator so as to suppress the disturbance with a degree of suppression according to the possibility that the driver will perform correction steering with respect to the vehicle behavior at the time of disturbance input. A steering control device. A vehicle equipped with a steering control device including a steering wheel installed at a front position of a driver seat, an actuator capable of adjusting a steering torque of the steering wheel, and a control means for controlling an output torque of the actuator,
Steering state quantity detection means for detecting at least one of a steering angle and a steering angular velocity as a steering state quantity, a steering input to the steering wheel by the driver and a steering input by the actuator, and an actual state detected by the steering state quantity detection means And a plurality of disturbance estimation means for estimating a plurality of disturbances having different frequency bands input to the vehicle based on the steering state quantity of the vehicle, and an output torque of the actuator so as to suppress the disturbance estimated by the disturbance estimation means A vehicle having a plurality of disturbance compensation means for correcting the disturbance with a correction degree corresponding to the frequency band of the disturbance. A steering control method comprising an actuator capable of adjusting a steering torque and a control means for controlling an output torque of the actuator,
Based on the steering input by the driver, the steering input by the actuator, and the actual steering state quantity, the actuator estimates a plurality of disturbances having different frequency bands input to the vehicle, and suppresses the disturbances. The steering control method is characterized in that the output torque is corrected with a correction degree corresponding to the frequency band of the disturbance.

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