JPH0561147B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an actual steering angle control device for a vehicle that is capable of freely controlling the motion performance of a vehicle during steering, and particularly relates to an improvement in control accuracy. The present invention relates to an actual steering angle control device for a vehicle.

(Prior art) Vehicles equipped with conventional mechanical link steering devices are configured to steer the front wheels in response to the steering angle of the steering wheel, and the dynamic performance associated with steering depends on the vehicle's vehicle performance. The driving performance is determined uniformly based on specifications, and is unique to each vehicle type.

On the other hand, the applicant of the present application has previously
No. 147018 (see JP-A-61-27763), patent application 1982-
No. 188153 (see JP-A-61-67665), patent application No. 1881-
No. 188158 (see Japanese Patent Application Laid-Open No. 61-67670), etc.
Assuming a target vehicle model with target dynamic performance, based on the vehicle specifications and equation of motion regarding the target vehicle model, target values of motion variables corresponding to the steering wheel steering angle and vehicle speed, that is, the target vehicle model exhibits. A motion state quantity representing motion performance is obtained, and the steering angle of the vehicle's wheels (at least one of the front wheels or rear wheels) is determined so that the vehicle (vehicle equipped with the device) achieves this motion state quantity target value. We are proposing a control device.

In other words, by using this device, it is possible to freely control exercise performance.

(Problems to be Solved by the Invention) By the way, the inventor of the present application has the following problems regarding the above device:
Through further research, we discovered the following improvements.

That is, for example, by controlling the actual steering angle of the rear wheels,
When trying to perform control that makes the yawing motion characteristics ideal, it is sufficient to find the target value of the motion state quantity of the yawing motion as the above-mentioned motion state quantity target value, but it is necessary to realize this motion state quantity target value in the own vehicle. In order to determine the actual steering angle of the rear wheels required for this purpose, it is necessary to consider the entire planar motion of the vehicle, so it is also necessary to know the state quantity of the own vehicle's lateral motion. Similarly, in order to make the lateral motion characteristics ideal, in addition to finding the target value of the motion state quantity of the lateral motion, it is also necessary to know the state quantity of the own vehicle's yawing motion.

The device according to the prior application was configured to perform both the calculation of the target value of the amount of motion state and the calculation for knowing the amount of motion state of the own vehicle.
The computational burden was heavy.

In particular, the calculation for determining the amount of motion state of the own vehicle involves solving a differential equation using the vehicle specifications of the own vehicle, which is prone to errors and requires a long calculation time.

(Means for solving the problems) In order to solve the above problems, the present invention provides the first
It is equipped with the means shown in the figure.

The motion state quantity target value calculation means 102 calculates the steering amount θ _s of the steering wheel detected by the steering wheel steering amount detection means 100 and the vehicle speed detected by the vehicle speed detection means 101 based on a vehicle model having preset target motion performance. A target value of the motion state corresponding to the vehicle speed V is determined.

The motion state quantity detection means 103 detects the actual motion state quantity B of the own vehicle, which is a type of motion state quantity different from the motion state quantity target value.

The wheel steering angle target value determining means 104 determines the front or rear wheels for realizing the target motion state value in the own vehicle based on the target motion state quantity value, the detected motion state value B, and the vehicle specifications of the own vehicle. A target value of at least one wheel steering angle is determined.

The wheel steering means 105 steers the wheels corresponding to the target value of the wheel steering angle.

(Operation) The motion state quantity target value obtained by the motion state quantity target value calculation means 102 is determined as the motion state quantity of the own vehicle by the wheel steering angle target value determining means 104 and the wheel steering means 105. By realizing this, the preset target driving performance is realized in the own vehicle.

Further, the present invention provides that the wheel steering angle target value determination means 104 determines the target value of the actual wheel steering angle necessary for realizing the motion state quantity target value in the own vehicle. The motion state quantity of the own vehicle, which is different from the above-mentioned motion state quantity target value and which is necessary to know the entire motion, is detected by the motion state quantity detection means 103 without being calculated by calculation. I am trying to use the value.

This allows you to reduce the amount of calculations and
Since control with fewer errors can be performed and the calculation time can be shortened compared to the case using calculations, responsiveness can be improved.

(Example) FIG. 2 shows the configuration of a first embodiment of the present invention.

The arithmetic processing unit 1A calculates the vehicle speed V detected by the vehicle speed sensor (vehicle speed detection means) 3, the steering angle θ _{s of the steering wheel 8 detected by the steering wheel steering angle sensor (handle steering amount detection means) 2, and the steering angle θ s} of the vehicle body. Lateral velocity V _y detected by a lateral velocity sensor (motion state quantity detection means) 15 provided near the center of gravity
is input to calculate the motion state quantity target value and the rear wheel steering angle target value _δR .

The lateral speed sensor 15 may be, for example, an optical ground vehicle speed meter mounted with its sensing direction directed in the lateral direction of the vehicle body. In addition, the method does not directly detect the lateral speed, but for example, as shown in FIG.
8. An integrator 19 may be used to indirectly detect the lateral velocity V _y from the calculation V _y =∫(α+V·)dt (1).

The rear wheel steering device (wheel steering means) 5 is a device that performs steering control of the rear wheels 11 and 12 based on data of a rear wheel steering angle target position δ _R given from the arithmetic processing device 1A.

It is the hydraulic steering device 7 that actually steers the rear wheels 11 and 12. This hydraulic steering device 7 is controlled by the rear wheel steering device 5.

That is, the rear wheel steering device 5
The hydraulic pressure applied to the hydraulic steering device 7 is changed in accordance with the rear wheel steering angle target value δ _R input from A, and the actual steering angles of the rear wheels 11 and 12 are set to the rear wheel steering angle target value δ.
The hydraulic steering device 7 is controlled so as to match _R (details are described in Japanese Patent Application No. 59-188153).

The front wheels 9 and 10 are steered by a conventional mechanical link type steering device 6 in accordance with a steering angle θ _s of a steering handle 8.

FIG. 4 is a flowchart showing the processing executed by the arithmetic processing device 1A when the arithmetic processing device 1A is constructed using a microcomputer. The process shown in the figure is repeatedly executed at predetermined time intervals, and initialization is performed when the ignition switch is turned on. and,
After this initialization, steps 21 and 22 corresponding to the motion state quantity target value calculating means and steps 23, 24 and 25 corresponding to the wheel steering angle target value determining means are executed as follows.

In step 21, each data of the steering wheel steering angle θ _s inputted from the steering wheel steering angle sensor 2 and the vehicle speed V inputted from the vehicle speed sensor 3 is read.

In step 22, the amount of motion state that the target vehicle model exhibits when the above-mentioned steering wheel steering angle θ _s and vehicle speed V are given to the target vehicle model is calculated by calculating the target vehicle model having a preset target motion performance. Of these, two are the yaw rate and yaw angular acceleration.
Find the amount of motion state related to the two coiling motions,
Let these be the yaw rate target value and the yaw angular acceleration target value.

The target vehicle model is a mathematical model formed by using vehicle specifications and equations of motion of the vehicle, and corresponds to a reference model in model following control.

The specific calculation formula for calculating the above-mentioned yaw rate target value and yaw angular acceleration target value is given in the patent application published in 1983.
Please refer to No.-188158.

In this way, the yaw rate target value and yaw angular acceleration target value are determined based on the target vehicle model.
is temporarily stored and used in the calculation executed in step 24, which will be described later.

In the next step 23, the lateral velocity sensor 1
Detected value of the actual lateral speed of the own vehicle detected in step 5
Read V _y .

In the next step 24, the yaw rate target value and yaw angular acceleration target value obtained in step 22 are determined.
By applying the detected lateral velocity value V _y read in step 23 above to the own vehicle model that is a mathematical model of the motion characteristics of the own vehicle (also giving the vehicle speed V and steering wheel steering angle θ _s ), these values can be calculated. The actual steering angle of the rear wheels required to achieve the _target values .

The specific calculation _of this rear wheel steering angle target value δR is as follows.

C _F = eK _F {θ _s /N-(V _y +LC _F・)/V} ...(2) C _R = (L _F C _F -1/2I _z ¨)/L _R ...(3) δ _R = C _R / K _R + V _y - L _R /.../V ...... (4) Here, C _F : Front wheel cornering force C _R : Rear wheel cornering force, and these C _F and C _R are calculated. It is a variable that is determined in the process. Also, eK _F : Front wheel equivalent cornering power K _R : Rear wheel cornering power I _z : Yaw inertia L _F : Distance between the front axle and center of gravity L _R : Distance between rear axle and center of gravity N: Steering gear ratio; is the vehicle specifications of the own vehicle, that is,
are constants (therefore, θ _s , V, and V _y are detected values).

In this way, in order to determine the rear wheel steering angle target value δ _R , at least the planar motion of the vehicle, that is,
It is necessary to consider yawing motion and lateral motion, and in this example, regarding yawing motion,
A yaw rate target value and a yaw angular acceleration target value are given, and for lateral movement, a detected value of lateral velocity _Vy is given.

By using the detected value V _y as the lateral velocity given as the motion state quantity related to the lateral motion, there is no need to calculate the same lateral velocity by solving a differential equation, and the above equation (2) ~ It becomes possible to determine δ _R using only the four simple arithmetic operations in (4). For reference, the calculation formula for determining the lateral velocity is shown below.

V _y =∫{(2C _F +2C _R )/M-・V}dt...(5) However, M is the vehicle body mass.

The rear wheel steering angle target value δ _R thus determined is outputted to the rear wheel steering device 5 in step 25.

As a result, the actual steering angles of the rear wheels 11 and 12 become equal to the rear wheel steering angle target value δ _R , and the yaw rate and yaw angular acceleration of the own vehicle become equal to the yaw rate target value and the yaw angular acceleration target value. . Therefore, the driving performance of the own vehicle matches the target driving performance of the target vehicle model.

Next, the configuration of a second embodiment of the present invention is shown in FIG. In addition, in the same figure, the first
Components that are the same as those in the embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, the target value of the lateral motion state quantity is determined as the motion state quantity target _value obtained from the target vehicle model, and the vehicle body The detection value of the actual yaw rate of the vehicle detected by the yaw rate sensor motion state quantity detection means 20 installed near the center of gravity is used.

Therefore, when the arithmetic processing device 1B is configured using a microcomputer, the processing executed by the arithmetic processing device 1B is as shown in FIG. In this figure, steps 21 and 31 correspond to the motion state quantity target value calculation means, and steps 32, 33, and 25
corresponds to wheel steering angle target value determining means.

Note that among the steps in FIG. 6, steps that perform the same processing as steps in the flowchart showing the processing executed in the first embodiment shown in FIG. 4 are given the same reference numerals and will not be described. Omitted.

In the process of step 31, based on the target vehicle model, when the steering wheel steering angle θ _s and the vehicle speed V are given to the target vehicle model, the amount of lateral motion state exhibited by the target vehicle model, that is, the lateral velocity and the lateral velocity are calculated. Find the directional translational acceleration and convert them into the lateral velocity target value V
_y and the lateral translational acceleration target value V· _y .

The specific calculation formula for calculating the above-mentioned lateral velocity target value V _y and lateral translational acceleration target value V・ _y is as follows:
Patent Application No. 1982-152564 (see Japanese Patent Application No. 15170-1983)
Please refer to it.

In step 32, the detected value of the actual yaw rate of the vehicle detected by the yaw rate sensor 20 is determined.

In the next step 33, the lateral speed target value Vy , the lateral translational acceleration target value _Vy obtained in the above step ₃₁ , and the yaw rate detection value read in the above step 32 are given to the vehicle model ( vehicle speed V and steering wheel steering angle θ _s ), the above target values V _y , V _y
The actual steering angle of the rear wheels required to achieve this in the own vehicle is determined, and this is set as the rear wheel steering _angle target value δR .

The specific calculation _of this rear wheel steering angle target value δR is as follows.

C _F = eK _F {θ _s /N-( V _y +L _F・)/V} ...(6) C _R =1/2M( V・ _y +V・)-C _F ......(6) δ _R = C _R /K _R + V _y −L _R /・/V ......(7) Here, M is the vehicle weight of the own vehicle, which is a constant,
The rest is the same as that of the first embodiment. The detected values are ·, θ _s , and V.

In this way, in this embodiment as well, similarly to the first embodiment, the calculation of the rear wheel steering angle target value δ _R is performed using the formula
As shown in (5) to (7), the calculation can be performed using only four simple arithmetic operations, and the calculation time and errors can be reduced. For reference, the formula for calculating the yaw rate is shown below.

・=∫{2(C _F L _F −C _R L _R )/I _z }dt ...(8) In each of the above embodiments, the actual steering angle of the rear wheels 11 and 12 is controlled to adjust the own vehicle's steering angle. Although an example of controlling the driving performance has been shown, the present invention can also control the driving performance of the own vehicle by controlling the actual steering angles of both the front wheels and the rear wheels.

Furthermore, in each of the above embodiments, the yawing motion and the lateral motion of the planar motion of the vehicle are mainly controlled, and the yaw rate, each yaw acceleration,
Although an example has been shown in which the lateral velocity and the lateral translational acceleration are used as the motion state quantity target value and the detected value, the present invention is not limited to these examples, and for example, as the lateral motion state quantity, It is also possible to use lateral acceleration, sideslip angle, etc.

Furthermore, it is also possible to use not only the state quantity of the planar motion of the vehicle but also the state quantity of pitch motion, roll motion, etc. as the target value or the detected value.

Furthermore, in each of the above embodiments, an example is shown in which the steering wheel angle sensor 2 is provided as a detector for the amount of steering of the steering wheel. It is also possible to use a sensor or a sensor that detects the steering speed.

(Effects of the Invention) As explained in detail above, the present invention provides a method for determining target values of motion state quantities using a target vehicle model in order to achieve a preset target motion performance in the own vehicle. The system is configured to determine the target value of the wheels necessary for realizing the target value of the motion state quantity in the own vehicle, and to make the actual steering angle of the wheels coincide with the target value of the steering angle.

With this, the present invention improves the driving performance of the own vehicle,
It is possible to match the above-mentioned target exercise performance.

Further, the present invention provides a motion state quantity of the own vehicle that is different from the target quantity of the above motion state quantities, which is necessary to know the entire motion of the own vehicle when determining the target value of the steering angle of the wheels. The actual motion state quantity of the own vehicle is detected and this detected value is used instead of being calculated by calculation.

As a result, the present invention eliminates the need for calculations such as solving complex differential equations, reduces the amount of calculations, and reduces control errors caused by calculation errors and the like. Furthermore, since calculation time can be shortened, responsiveness can be increased.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a block diagram of the first embodiment of the present invention, FIG. 3 is a block diagram showing another configuration example of the lateral velocity sensor, and FIG. A flowchart showing the processing executed in the arithmetic processing device in the figure, FIG. 5 is a block diagram of the second embodiment of the present invention, and FIG. 6 shows the processing executed in the arithmetic processing device in FIG. It is a flowchart. 100...Steering wheel steering amount detection means, 101...
...Vehicle speed detection means, 102... Motion state quantity target value calculation means, 103... Motion state quantity detection means, 104
...Wheel steering angle target value determining means, 105...Wheel steering means, 1A, 1B... Arithmetic processing device (motion state quantity target value calculating means), 2... Steering wheel steering angle sensor (steering wheel steering amount detecting means) , 3... Vehicle speed sensor (vehicle speed detection means), 5... Rear wheel steering device (wheel steering means), 7... Hydraulic steering device, 8
...Steering handle, 9,10...Front wheel,
11, 12... Rear wheel, 15... Lateral speed sensor (motion state quantity detection means), 20... Yaw rate sensor (motion state quantity detection means), _θs ... Handle steering angle, V... Vehicle speed, ...Yaw rate target value,...
... Yaw angular acceleration target value, ... Yaw rate detected value, V _y ... Lateral speed target value, V・ _y ... Lateral translational acceleration target value, V _y ... Lateral speed detected value, δ _R
...Rear wheel steering angle target value.

Claims (1)

[Scope of Claims] 1. Steering wheel steering amount detection means for detecting a steering amount of the steering wheel; vehicle speed detection means for detecting vehicle speed; a motion state quantity target calculation means for calculating a target value of a motion state quantity corresponding to the steering amount of the steering wheel and the vehicle speed; and a motion state quantity target value of a different type from the motion state quantity target value calculated by the motion state quantity target value calculation means. A motion state quantity detection means for detecting an actual motion state quantity of the host vehicle, which is a state quantity; and a motion state quantity detection means detected by the motion state quantity detection means, the motion state quantity target value, and the own vehicle. Wheel steering angle target value determining means for determining a target value of a wheel steering angle of at least one of a front wheel or a rear wheel for realizing the motion state quantity target value in the own vehicle based on the vehicle specifications; An actual steering angle control device for a vehicle, comprising a wheel steering means for steering a wheel corresponding to the wheel steering angle target value. 2. A patent characterized in that the motion state quantity target value is a target value of a motion state quantity related to yawing motion, and the detected value of the motion state quantity is a detected value of a motion state quantity related to lateral motion. An actual steering angle control device for a vehicle according to claim 1. 3. A patent characterized in that the motion state quantity target value is a target value of a motion state quantity related to lateral motion, and the detected value of the motion state quantity is a detected value of a motion state quantity related to yawing motion. An actual steering angle control device for a vehicle according to claim 1.