JP3132299B2 - Auxiliary steering angle control device for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary steering angle control device for a vehicle which provides an auxiliary steering angle by feed forward control + feedback control.

[0002]

2. Description of the Related Art Conventionally, as an auxiliary steering angle control device for a vehicle for giving an auxiliary steering angle to rear wheels by feedforward control and yaw rate feedback control, for example, Japanese Patent Application Laid-Open No.
An apparatus described in Japanese Patent No. 18168 is known.

On the other hand, Japanese Patent Application Laid-Open No. 57-55402 discloses that a main CPU and a sub CPU are used in an in-vehicle engine control system in order to improve fail-safe performance. A technique is described in which when a predetermined difference occurs between two CPU outputs, the arithmetic processing control system fails.

Therefore, when the latter fail-safe technology is employed in the former vehicle auxiliary steering angle control device, the main CPU and the sub CPU are respectively provided with an auxiliary steering angle feedforward target value calculating section and an auxiliary steering angle feedback. Two CPUs each having a target value calculation unit and an auxiliary steering angle target value calculation unit, and which are the result of performing exactly the same arithmetic processing by both CPUs
This is a combination device that compares outputs.

[0005]

However, in the vehicle auxiliary steering angle control device according to the above combination, since the same arithmetic processing is performed by both the main CPU and the sub CPU, the sub CPU side is equivalent to the main CPU. Requires a large program capacity, and increases the apparatus cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicular auxiliary steering angle control device which provides an auxiliary steering angle by feedforward control + feedback control. It is intended to reduce the cost of the apparatus while ensuring the above.

[0007]

According to a first aspect of the present invention, a vehicle speed detecting means a and a steering steering angle detecting means b are provided as shown in FIG. An auxiliary steering angle feedforward target value calculating unit c for calculating an auxiliary steering angle feedforward target value based on the vehicle speed detection value and the steering steering angle detection value, and a motion state amount estimating unit for estimating a motion state amount generated in the own vehicle. d and
A motion state quantity detection means e for detecting a motion state quantity similar to the estimated motion state quantity, and an auxiliary steering angle feedback target value is calculated by compensation based on a deviation between the motion state quantity detection value and the motion state quantity estimation value. Auxiliary steering angle feedback target value calculating means f; auxiliary steering angle target value calculating means g for calculating an auxiliary steering angle target value based on the auxiliary steering angle feedforward target value and the auxiliary steering angle feedback target value; An auxiliary steering angle control device for a vehicle, comprising: an auxiliary steering angle control unit i for outputting a control command for obtaining a target value to an auxiliary steering angle actuator h; Estimating means d, auxiliary steering angle feedback target value calculating means f, and auxiliary steering angle target value calculating means g
And an auxiliary steering angle feedforward target value calculating means c and an auxiliary steering angle target value calculating means g. When calculating the auxiliary steering angle target value, the auxiliary steering angle feedback target value is determined by the main CPUj. A sub-CPU k obtained by communication from the main CPU j, and output comparison means m for comparing an auxiliary steering angle target value output from the main CPU j with an auxiliary steering angle target value output from the sub CPU k. I do.

[0008] According to a second aspect of the present invention, in the first aspect,
In the vehicle auxiliary steering angle control device described above, the auxiliary steering angle feedback target value calculating means f is provided with a steering angle limiter p for limiting the magnitude of the auxiliary steering angle feedback target value.

According to a third aspect of the present invention, there is provided the first aspect of the present invention.
In the vehicle auxiliary steering angle control device described above, the output comparing means m determines that the deviation between the auxiliary steering angle target value output from the main CPU j and the auxiliary steering angle target value output from the sub CPU k exceeds a predetermined value. Then, a fail-safe means q for stopping the control of the auxiliary steering angle actuator h is provided.

According to a fourth aspect of the present invention, there is provided the first aspect of the present invention.
4. The auxiliary steering angle control device for a vehicle according to any one of the first to third aspects, wherein the motion state amount detecting means e is a yaw rate sensor, and the motion state amount estimating means d is a means for obtaining an estimated yaw rate.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention,
In the vehicle auxiliary steering angle control device described above, the motion state amount estimating means d obtains an estimated yaw rate based on at least an auxiliary steering angle feedforward target value, a vehicle speed detection value, a steering steering angle detection value, an actuator model, and a vehicle model. Means.

[0012]

The operation of the first invention will be described.

When the vehicle is running, the main CPU j uses the auxiliary steering angle feedforward target value calculating means c based on the detected vehicle speed detected by the vehicle speed detecting means a and the detected steering angle detected by the steering angle detecting means b. A steering angle feedforward target value is calculated.

On the other hand, a motion state quantity estimating means d estimates a motion state quantity occurring in the own vehicle, and a motion state quantity detecting means e detects a motion state quantity of the same kind as the estimated motion state quantity. Angle feedback target value calculating means f
In, the auxiliary steering angle feedback target value is calculated by compensation based on the deviation between the motion state amount detection value and the motion state amount estimation value.

The auxiliary steering angle target value calculating means g calculates an auxiliary steering angle target value based on the auxiliary steering angle feedforward target value and the auxiliary steering angle feedback target value. A control command for obtaining the auxiliary steering angle target value is output to the auxiliary steering angle actuator h.

When the vehicle is running, the sub-CPUk uses the auxiliary steering angle feed forward target value calculating means c based on the vehicle speed detection value from the vehicle speed detection means a and the steering angle detection value from the steering angle detection means b. A steering angle feedforward target value is calculated. The auxiliary steering angle feedback target value is obtained by communication from the main CPU j. The auxiliary steering angle target value calculating means g calculates the auxiliary steering angle based on the auxiliary steering angle feedforward target value and the auxiliary steering angle feedback target value. A target value is calculated.

When the vehicle is running, the output comparing means m
Output of auxiliary steering angle target value from main CPUj and sub CPU
Then, the output of the auxiliary steering angle target value output from k is compared.

That is, the auxiliary steering angle feedforward target value has an output of, for example, about ± 1 °, whereas the auxiliary steering angle feedback target value based on a deviation caused by disturbance or the like is, for example, about ± 0.2 °. Is sufficient, and the output value level is much larger for the auxiliary steering angle feedforward target value. Focusing on this point, the sub CPUk obtains the auxiliary steering angle feedback target value having a small effect on the output by communication from the main CPUj.

Therefore, basically, a system for comparing outputs from two CPUs is maintained, so that high fail-safe performance is ensured, and the operation capacity of the sub CPU k is reduced, thereby reducing the apparatus cost. Can be

The operation of the second invention will be described.

In calculating the auxiliary steering angle feedback target value, the auxiliary steering angle feedback target value calculating means f
In addition, since the steering angle limiter p for limiting the magnitude of the auxiliary steering angle feedback target value is provided, the output value level of the auxiliary steering angle feedback target value can be suppressed to a predetermined limit value or less.

The operation of the third invention will be described.

The output comparing means m is connected to the main CPU j
When it is determined that the deviation between the auxiliary steering angle target value output from the sub CPU k and the auxiliary steering angle target value output from the sub CPUk exceeds a predetermined value, the control of the auxiliary steering angle actuator h is stopped by the fail-safe means q. , Secure fail-safe performance.

The operation of the fourth invention will be described.

In calculating the auxiliary steering angle feedback target value, the auxiliary steering angle feedback target value calculating means f compensates based on the deviation between the yaw rate detection value from the yaw rate sensor and the estimated yaw rate from the motion state amount estimating means d. Thus, the auxiliary steering angle feedback target value is calculated.

Therefore, in the vehicle auxiliary steering angle control device for providing the auxiliary steering angle by the feedforward control and the yaw rate feedback control, the device cost can be reduced while ensuring high fail-safe performance.

The operation of the fifth invention will be described.

In estimating the motion state quantity generated in the own vehicle by the motion state quantity estimating means d, in the actuator model, the auxiliary steering angle actuator h actually operates according to the auxiliary steering angle feedforward target value using the actuator dynamic characteristic. Is estimated, and in the vehicle model,
The yaw rate is estimated using the estimated auxiliary steering angle, the detected vehicle speed, the detected steering angle, and the linear two-degree-of-freedom plane vehicle model.

Therefore, by estimating the yaw rate using an actuator model other than the vehicle model, highly accurate feedback control not affected by the dynamic characteristics of the auxiliary steering angle actuator h is achieved.

[0030]

Embodiments of the present invention will be described below with reference to the drawings.

First, the configuration will be described.

FIG. 2 is an overall system diagram showing a four-wheel steering vehicle to which the vehicle auxiliary steering angle control device according to the embodiment of the present invention is applied.

In FIG. 2, the front wheels 1 and 2 are steered by a steering handle 3 and a mechanical link type steering mechanism 4.
Done by This includes, for example, a steering gear, a pitman arm, a relay rod, side rods 5, 6, knuckle arms 7, 8, and the like.

The steering of the rear wheels 9, 10 is performed by an electric steering device 11 (corresponding to an auxiliary steering angle actuator h). The rear wheels 9, 10 are connected by a rack shaft 12, side rods 13, 14, and knuckle arms 15, 16, and a rack tube 17 in which the rack 12 is inserted has a speed reduction mechanism 18 and a motor 19.
The motor 19 and the fail-safe solenoid 20 are provided with a vehicle speed sensor 21 (corresponding to a vehicle speed detecting means a) and a front wheel steering angle sensor 22.
(Corresponding to the steering angle detecting means b), the rear steering angle sub-sensor 23, the rear steering angle main sensor 24, the yaw rate sensor 25 (corresponding to the motion state amount detecting means e) and the like. You.

FIG. 3 is a sectional view showing a specific structure of the electric steering apparatus 11.

In FIG. 3, the rack tube 17 in which the rack 12 is inserted is fixed to the vehicle body via a bracket. Side rods 13 and 14 are connected to both ends of the rack 12 via ball joints 30 and 31. The reduction mechanism 18 includes a motor pinion 32 connected to the motor shaft of the motor 19, a ring gear 33 meshing with the motor pinion 32, and a rack pinion 35 fixed to the ring gear 33 and meshing with the rack gear 12a. Have been. Therefore, when the motor shaft of the motor 19 rotates, the rotation is transmitted to the motor pinion 32 → the ring gear 33 → the rack pinion 35, and the rack shaft 12 moves in the axial direction due to the engagement between the rotating rack pinion 35 and the rack gear 12a. The rear wheels 9, 10 are steered. This rear wheel 9,10
Is proportional to the amount of movement of the rack shaft 12, that is, the amount of rotation of the motor shaft.

The rack pinion 35 is provided with a rear steering angle main sensor 24 having a potentiometer structure for detecting a rear wheel steering angle based on the rotation amount.

The fail-safe solenoid 20 includes:
The lock pin 20a is provided so as to be able to advance and retreat, and when a failure occurs in the electronic control system or the like, the lock pin 20a is fitted into a lock groove 12b formed in the rack shaft 12 so that the rack shaft 12 and the rear wheels 9, 10 are moved. It is fixed at a position to maintain the neutral steering angle position.

FIG. 4 is a block diagram showing an electronic control system centered on the controller 26.

In FIG. 4, 21 is a vehicle speed sensor, 22 is a front wheel steering angle sensor, 24 is a rear steering angle main sensor, 25 is a yaw rate sensor, 26 is a controller, 26a is a main CPU, 26b is a sub CPU, and 26c is a motor drive. Circuit, 26d is a comparator (corresponding to output comparing means m), 26e
Is a fail-safe circuit (equivalent to fail-safe means q)
It is.

The main CPU 26a includes a feedforward target value calculating section 261a (corresponding to an auxiliary steering angle feedforward target value calculating means c), an estimated yaw rate calculating section 262a (corresponding to a motion state amount estimating means d), and a feedback target. Value calculating section 263a (corresponding to auxiliary steering angle feedback target value calculating means f), rear wheel steering angle target value calculating section 264a (corresponding to auxiliary steering angle target value calculating means g), and steering angle servo calculating section 265a (auxiliary). Steering angle control means i).

The sub CPU 26b includes a feedforward target value calculating section 261b (corresponding to an auxiliary steering angle feedforward target value calculating means c) and a rear wheel steering angle target value calculating section 264b (an auxiliary steering angle target value calculating means g). And a steering angle servo calculation unit 265b. When the rear wheel steering angle target value δR ^* is calculated by the rear wheel steering angle target value calculation unit 264b, the rear wheel steering angle feedback target value δRFB ^* Obtained from the CPU 26a by internal communication using signal lines.

The motor drive circuit 26c converts the motor command current IM ^* from the steering angle servo calculator 265a into the motor 19
To the motor drive current IM.

The comparator 26d includes a main CPU 26a
Motor command current IM ^* and inputs the motor calculated current IS ^* from the sub CPU26b from, comparing both current level if there is a difference larger than a predetermined.

The fail-safe circuit 26e outputs a signal indicating a failure time from the comparator 26d,
A command to execute a predetermined fail-safe operation is output.

Next, the operation will be described.

[Control Processing Operation in Main CPU] FIG. 5 is a flowchart showing a flow of control processing operation performed by the main CPU 26a of the controller 26.
Each step will be described.

In step 40, the vehicle speed V, the steering angle θ, the actual yaw rate ψ's, and the rear steering angle main sensor value δ
rs is read.

Here, the actual yaw rate ψ's is the yaw rate sensor value Vψ 'from the yaw rate sensor 25 and the latest yaw rate zero correction memory value V obtained by the detected yaw rate correction processing for removing the influence of the temperature drift.
Calculated by ψ'om.

In step 41, the rear wheel steering angle feedforward target value δRFF is calculated by the following equation based on the phase inversion delay control method using the vehicle speed V and the steering angle θ.
^* (Hereinafter, * represents a target value) is calculated.

ΔRFF ^* = Kθ + τθ + τ′θ The calculation processing in this step is performed by the feedforward target value calculation unit 261a.

In step 42, when the rear wheel steering angle feedforward target value δRFF ^* is given using the actuator model, the rear wheel steering angle estimated value δRFF is the amount by which the rear wheel steering angle actuator actually steers the rear wheels. ^# (Hereinafter, # represents an estimated value) is calculated. This actuator model is given by a transmission characteristic of an actual rear wheel steering angle obtained by driving an actual actuator in response to a rear wheel steering angle command value.

In step 43, a vehicle model is used to calculate an estimated yaw rate value ψ '^# when the vehicle is assumed to run with the vehicle speed V, the steering angle θ, and the estimated rear wheel angle value δRFF ^# . As this vehicle model, a linear two-degree-of-freedom plane vehicle model is used.

In step 44, the estimated yaw rate ψ's ^# is calculated from the yaw rate estimated value ψ '^# using the yaw rate sensor model. This yaw rate sensor model is
It is given by a transfer function based on experimental results of sensor dynamic characteristics such as the frequency response of the sensor.

The calculation processing in steps 42 to 44 is performed by the estimated yaw rate calculation section 262a.

In step 45, the yaw rate deviation ψ'e is calculated from the difference between the actual yaw rate ψ's and the estimated yaw rate ψ's ^# .

In step 46, the yaw rate deviation ψ'e is input and the output signal ψ'ec1 from which the high frequency noise included in the output of the yaw rate sensor 25 is removed is obtained by the feedback compensator-1 constituting a first-order lag filter. .

In step 47, a feedback compensator-2 constituting a first-order / first-order filter receives ψ'ec1 and the vehicle speed V, and outputs an output signal ψ'ec2 in which the transient response of the vehicle to disturbance is adjusted. obtain.

In step 48, the feedback rear wheel steering angle command value δRFBO ^* is calculated by using the feedback proportional gain Kp and ψ'ec2 and the vehicle speed V as inputs.

In step 49, the steering angle limiter
Feedback rear wheel steering angle command value δRFBO according to vehicle speed V
A feedback rear wheel steering angle limit command value ΔRFBL ^{* in} which the maximum value of ^* is smoothly limited to, for example, ± 0.2 ° is calculated.

In step 50, the small rear change absorber absorbs the feedback rear wheel steering angle limit command value δRFBL based on δRFBL ^* and the rear wheel steering angle feedback target value δRFB ^*.
The feedback rear wheel steering angle limit command value ΔRFBH ^* is calculated by providing a hysteresis to ^* and removing minute yaw rate vibrations due to feedback.

In step 51, a feedback rear wheel steering angle limit command value δRFBH ^* is input by an actuator phase compensator constituting a secondary / secondary filter, and a transfer characteristic set in the actuator control system is desired. Change the transfer characteristics to the rear wheel steering angle feedback target value δRFB ^*
Is calculated.

The calculation processing of steps 45 to 51 is performed by the feedback target value calculation section 263a.

In step 52, the rear wheel steering angle feed forward target value δRFF ^* and the rear wheel steering angle feedback target value δ
Based on the sum with RFB ^* , a rear wheel steering angle target value ΔR ^* is calculated. The calculation processing in this step is performed by the rear wheel steering angle target value calculation unit 26.
4a.

In step 53, the motor command current IM ^* for obtaining the rear wheel steering angle target value δR ^* by using the rear steering angle main sensor value δrs and the robust model matching method is output to the motor drive circuit 26c and the comparator 26d. You. The processing in this step is performed by the steering angle servo calculator 265a.

[Control Processing Operation by Sub CPU] FIG. 6 is a flowchart showing a flow of control processing operation performed by the sub CPU 26b of the controller 26. Each step will be described below.

In step 60, the vehicle speed V and the steering angle θ are read.

In step 61, a rear wheel steering angle feedforward target value δRFF ^* is calculated by an equation based on a phase inversion delay control method using the vehicle speed V and the steering angle θ as in step 41 described above.

The calculation processing in this step is performed by the feedforward target value calculation section 261b.

In step 62, the rear wheel steering angle feedback target value δRFB ^* is read from the main CPU 26a.

In step 63, the rear wheel steering angle feedforward target value δRFF ^* obtained in step 61 and step 6
The rear wheel steering angle target value δR ^* is calculated based on the sum with the rear wheel steering angle feedback target value δRFB ^* read in Step 2. The calculation process in this step is performed by the rear wheel steering angle target value calculation unit 264b.

In step 64, the motor calculation current IS ^* for obtaining the rear wheel steering angle target value δR ^{* in} step 63 is output to the comparator 26d by using the rear steering angle main sensor value δrs and the robust model matching method. . The processing in this step is performed by the steering angle servo calculator 265b.

[Fail Detection by Output Comparison] FIG. 7 is a flowchart showing the flow of the failure detection processing operation performed by the comparator 26d of the controller 26.
Each step will be described.

In step 70, the motor command current IM ^* from the main CPU 26a and the motor calculation current IS ^* from the sub CPU 26b are input.

In step 71, the current value difference absolute value | ΔI
Is determined to be less than or equal to fail threshold value A. Here, | ΔI | is calculated by the equation | ΔI | = | IM ^* −IS ^* |.

In step 72, YES in step 71
When it is determined that the arithmetic processing control system is normal, the rear wheel steering angle control is continued.

In step 73, when the determination in step 71 is NO, it is determined that the arithmetic processing control system has failed.
A command for performing a fail-safe operation is output to the fail-safe circuit 26e. As the fail-safe operation, the rear wheel steering angle control is stopped, the rear wheel steering angle is fixed at the neutral position, and an alarm is issued.

[Rear Wheel Steering Angle Control Action] The rear wheel steering angle control action during traveling is performed by control processing performed by the main CPU 26a, and is executed according to the flowchart shown in FIG.

That is, in step 41, the vehicle speed V
The rear wheel steering angle feedforward target value ΔRFF ^* is calculated by an equation based on a phase inversion delay control method using the steering angle θ and the steering angle θ.

On the other hand, in steps 42 to 44, the estimated yaw rate に 's ^#
In steps 45 to 51, rear wheel steering angle feedback is performed by compensation based on a yaw rate deviation ψ'e which is a difference between the actual yaw rate ψ's based on the yaw rate sensor value V 値 'from the yaw rate sensor 25 and the estimated yaw rate ψ's ^#. The target value ΔRFB ^* is calculated.

Then, in step 52, the rear wheel steering angle target value δR ^* is calculated from the sum of the rear wheel steering angle feedforward target value δRFF ^* and the rear wheel steering angle feedback target value δRFB ^*. The motor command current IM ^* for obtaining the wheel steering angle target value δR ^* is output to the motor drive circuit 26c. Then, the motor drive current IM is supplied to the motor 19 of the electric steering device 11 by the motor drive circuit 26c.

[Fail Detection of Arithmetic Processing Control System] Fail detection of the arithmetic processing control system is executed according to the flowchart shown in FIG.

That is, in step 70, the main CPU 2
A motor command current IM ^* from 6a, the motor calculated current IS ^* is input from the sub CPU26b, current value difference absolute value in step 71 | [Delta] I | is determined whether the following fail threshold A, at step 71 When NO is determined, it is detected that the arithmetic processing control system has failed. This threshold value A is, for example, the limiter value 0.2 in step 49.
The current value is set to 0.4 ° which is twice the angle of 0.4 °.

This failure is detected by the main CPU 26a.
The calculation of the motor command current IM ^{* in} the above and the calculation of the motor calculation current IS ^{* in} the sub CPU 26b are conditions.
In U26b, as shown in the flowchart of FIG. 6, the rear wheel steering angle feedback target value δRFB ^* is set to the main CPU 26a ^.
From the sub-CPU 26b and omit the process of calculating the rear wheel steering angle feedback target value δRFB ^* in the sub CPU 26b.

This is a rear wheel steering angle feedforward target value δRFF ^* determined by the vehicle speed V and the steering angle θ ^.
Is, for example, about ± 1 °, whereas the rear wheel steering angle feedback target value δRFB ^* based on the yaw rate deviation ψ′e caused by disturbance or the like is, for example, ± 0 which is the limiter value of step 49 at the maximum. Output of about 2 °
The rear wheel steering angle feedback target value is more of the rear-wheel steering angle feedforward target value δRFF ^* as an output value level δRFB ^* more much larger. Focusing on this point, the sub CPU 26b
In this embodiment, the rear wheel steering angle feedback target value δRFB ^* having a small effect on the output is obtained by communication from the main CPU 26a.

Also, since the steering angle limiter is performed in step 49, even if the F / B target value calculation section 263a outputs an erroneous calculation value, the calculated value is reliably ± 0.2 ° or less, and high fail-safe performance is obtained. Can be secured.

Therefore, basically, the two CPUs 26
While maintaining a system for comparing the outputs from a and 26b, a high fail-safe performance is ensured, while the calculation capacity of the sub CPU 26b is greatly reduced, so that a small capacity CPU is used as the sub CPU 26b. The apparatus cost can be reduced as compared with the case where two CPUs having the same capacity are used.

[Yaw Rate Feedback Control Operation] In estimating the estimated yaw rate ψ's ^# generated in the own vehicle in steps 42 to 44, the actuator model 60 in step 42 uses the rear wheel steering angle feedforward target value δRFF ^* Type steering device 1
Then, the estimated rear wheel steering angle δRFF ^# from which the influence of the dynamic characteristic 1 is removed is calculated, and in the vehicle model 61 in step 43, the estimated rear wheel steering angle δRFF ^# , the vehicle speed V, and the steering angle θ
The yaw rate estimated value ψ ′ ^# is calculated using the linear two-degree-of-freedom plane vehicle model and the yaw rate estimated value ψ ′ output from step 43 using the dynamic characteristics of the yaw rate sensor 25 in the yaw rate sensor model 62 in step 44. ^#
The corrected yaw rate ψ's ^# is calculated.

Therefore, by calculating the estimated yaw rate ψ's ^# using the actuator model 60 and the yaw rate sensor model 62 in addition to the vehicle model 61, the dynamic characteristics of the rear wheel steering device 11 and the dynamic characteristics of the yaw rate sensor 25 are calculated. A highly accurate feedback control not affected by the above is achieved. In other words, since the estimated yaw rate ψ's ^# is accurately calculated, the feedback control does not work during normal driving unless it is affected by disturbance.

Next, the effects will be described.

(1) Feedforward target value calculation unit 2
61b, and a rear wheel steering angle target value calculation unit 264b. When calculating the rear wheel steering angle target value δR ^* , the rear wheel steering angle feedback target value δRFB ^* is obtained by communication from the main CPU 26a ^. Since the apparatus is provided with a comparator 26d for comparing the motor command current IM ^* from the CPU 26a with the motor calculation current IS ^* from the sub CPU 26b, the calculation results in the CPUs 26a and 26b and the current from the servo calculation units 265a and 265b are provided. It is possible to compare IM ^* and IS ^*, and reduce the cost of the apparatus while ensuring high fail-safe performance.

(2) Since the yaw rate sensor 25 is used as the motion state amount detecting means and the rear wheel steering angle feedback target value δRFB ^* is obtained from the deviation from the estimated yaw rate ψ's ^# , the feedforward control + the yaw rate feedback control is used. In the vehicular auxiliary steering angle control device that gives the rear wheel steering angle, the effect of the above (1), that is, reduction of the device cost can be achieved while ensuring high fail-safe performance.

(3) Estimated yaw rate に 's ^# generated in own vehicle
In estimating the rear wheel rudder angle feedforward target value δRFF ^*, an actuator model for calculating a rear wheel rudder angle estimated value δRFF ^# obtained by removing the influence of the dynamic characteristics of the electric steering device 11, and this rear wheel rudder angle estimation The value δRFF ^# , the vehicle speed V, the steering angle θ, and the vehicle model that calculates the yaw rate estimation value ψ ′ ^# using the linear two-degree-of-freedom plane vehicle model are used. A highly accurate feedback control not affected by the above can be achieved.

(4) Estimated yaw rate に 's ^# generated in own vehicle
Is estimated by using a yaw rate sensor model in addition to the actuator model and the vehicle model. In addition to the effect of (3), highly accurate feedback control not affected by the dynamic characteristics of the yaw rate sensor 25 is achieved. can do.

Although the embodiments have been described with reference to the drawings, the specific configuration is not limited to the embodiments, and any changes or additions without departing from the gist of the present invention are included in the present invention. It is.

For example, in the embodiment, the example of the auxiliary steering angle control device for giving the auxiliary steering angle only to the rear wheel has been described, but the auxiliary steering angle control device for giving the auxiliary steering angle only to the front wheel or the front and rear wheels may be used. Can be applied.

In the embodiment, the example in which the yaw rate is used as the motion state amount has been described. However, the lateral speed, the lateral acceleration, or the yaw momentum expressing these in a composite manner may be used.

In the embodiment, an example in which an electric steering device is used as the auxiliary steering angle actuator has been described. However, the present invention can be applied to a hydraulic or pneumatic steering device.

[0099]

According to the first aspect of the present invention, there is provided an auxiliary steering angle control device for a vehicle which provides an auxiliary steering angle by feedforward control + feedback control. A main CPU having estimating means, an auxiliary steering angle feedback target value calculating means, and an auxiliary steering angle target value calculating means; an auxiliary steering angle feedforward target value calculating means and an auxiliary steering angle target value calculating means; In calculating the angle target value, the auxiliary steering angle feedback target value is obtained by comparing the sub CPU obtained by communication from the main CPU with the auxiliary steering angle target value output from the main CPU and the auxiliary steering angle target value output from the sub CPU. Since the apparatus is provided with an output comparing means, it is possible to reduce the apparatus cost while securing high fail-safe performance. Cormorants effect can be obtained.

According to the second aspect of the invention, the output level of the auxiliary steering angle feedback target value can be suppressed to a predetermined limit value or less irrespective of the calculation result of the auxiliary steering angle feedback target value calculation means.

According to the third aspect of the present invention, the output comparing means outputs the auxiliary steering angle target value output from the main CPU to the sub C
If it is determined that the deviation from the output of the auxiliary steering angle target value from the PU exceeds a predetermined value, the control of the auxiliary steering angle actuator is stopped by the fail-safe means, so that reliable fail-safe performance can be ensured.

According to the fourth aspect of the present invention, a first aspect is provided.
In the auxiliary steering angle control device for a vehicle according to any one of the first to third aspects, the motion state amount detecting means is a yaw rate sensor, and the motion state amount estimating means is a means for obtaining an estimated yaw rate. In the vehicle auxiliary steering angle control device,
The effect that the effect of the invention described in claim 1 can be achieved is obtained.

In the invention according to claim 5, claim 4
In the vehicle auxiliary steering angle control device, the motion state amount estimating means includes means for obtaining an estimated yaw rate based on at least an auxiliary steering angle feedforward target value, a vehicle speed detection value, a steering steering angle detection value, an actuator model, and a vehicle model. As a result, the effect of the invention described in the fourth aspect can be achieved with high-accuracy yaw rate feedback control that is not affected by the dynamic characteristics of the auxiliary steering angle actuator.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to a claim showing an auxiliary steering angle control device for a vehicle according to the present invention.

FIG. 2 is an overall system diagram showing a four-wheel steering vehicle to which the vehicle auxiliary steering angle control device of the embodiment is applied.

FIG. 3 is a cross-sectional view of the electric steering device of the embodiment device.

FIG. 4 is a block diagram showing an electronic control system centered on a controller of the apparatus of the embodiment.

FIG. 5 is a flowchart illustrating a flow of a control processing operation performed by a main CPU of a controller of the embodiment device.

FIG. 6 is a flowchart illustrating a flow of a control processing operation performed by a sub CPU of a controller of the embodiment device.

FIG. 7 is a flowchart illustrating a flow of a failure detection processing operation performed by a comparator of a controller of the embodiment device.

[Explanation of symbols]

 a vehicle speed detecting means b steering rudder angle detecting means c auxiliary steering angle feedforward target value calculating means d moving state quantity estimating means e moving state quantity detecting means f auxiliary steering angle feedback target value calculating means g auxiliary steering angle target value calculating means h Auxiliary steering angle actuator i Auxiliary steering angle control means j Main CPU k Sub CPU m Output comparison means p Steering angle limiter q Fail safe means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI B62D 113: 00 137: 00 (58) Fields investigated (Int.Cl. ⁷ , DB name) B62D 6/00 B62D 7/14 G05B 9/03 G05B 11/32

Claims (5)

(57) [Claims] 1. A vehicle speed detecting means, a steering steering angle detecting means, an auxiliary steering angle feedforward target value calculating means for calculating an auxiliary steering angle feedforward target value based on a vehicle speed detected value and a steering steering angle detected value, Exercise state quantity estimating means for estimating the exercise state quantity occurring in the own vehicle, exercise state quantity detection means for detecting the same kind of exercise state quantity as the estimated exercise state quantity, exercise state quantity detection value and exercise state quantity estimation value An auxiliary steering angle feedback target value calculating means for calculating an auxiliary steering angle feedback target value by compensation based on a deviation from the target steering angle, and an auxiliary steering angle target value based on the auxiliary steering angle feedforward target value and the auxiliary steering angle feedback target value. An auxiliary steering angle target value calculating means for calculating, and an auxiliary steering angle control means for outputting a control command for obtaining the auxiliary steering angle target value to the auxiliary steering angle actuator. An auxiliary steering angle control device for a vehicle, comprising: a main CPU having an auxiliary steering angle feedforward target value calculating unit, a motion state amount estimating unit, an auxiliary steering angle feedback target value calculating unit, and an auxiliary steering angle target value calculating unit; An auxiliary steering angle feed forward target value calculating unit and an auxiliary steering angle target value calculating unit are provided. When calculating the auxiliary steering angle target value, the auxiliary steering angle feedback target value
A sub CPU obtained by communication from the PU; and output comparing means for comparing an auxiliary steering angle target value output from the main CPU with an auxiliary steering angle target value output from the sub CPU. Vehicle steering angle control device. 2. The auxiliary steering angle control device for a vehicle according to claim 1, wherein the auxiliary steering angle feedback target value calculating means includes a steering angle limiter for limiting the magnitude of the auxiliary steering angle feedback target value. Characteristic vehicle auxiliary steering angle control device. 3. The auxiliary steering angle control device for a vehicle according to claim 1, wherein the output comparing means is configured to determine a difference between an auxiliary steering angle target value output from the main CPU and an auxiliary steering angle target value output from the sub CPU. The vehicle auxiliary steering angle control device, further comprising: fail-safe means for stopping the control of the auxiliary steering angle actuator when it is determined that the control value exceeds a predetermined value. 4. The vehicle auxiliary steering angle control device according to claim 1, wherein the motion state amount detecting means is a yaw rate sensor, and the motion state amount estimating means is a means for obtaining an estimated yaw rate. Vehicle steering angle control device. 5. The vehicle auxiliary steering angle control device according to claim 4, wherein the motion state amount estimating means includes at least an auxiliary steering angle feedforward target value, a vehicle speed detection value, a steering steering angle detection value, an actuator model, and a vehicle. An auxiliary steering angle control device for a vehicle, which is means for obtaining an estimated yaw rate based on a model.