JPH0241979A - Yaw movement control method for vehicle - Google Patents

Abstract

PURPOSE:To avoid sudden correction control for yaw movement by estimating a steering angle and gradually correcting the output value of a steering angle sensor within a fixed time according to an error between the estimated steering angle and the detected steering angle of the steering angle sensor. CONSTITUTION:A steering angle detecting device 1 is a computer and includes yaw movement detecting means 3 for detecting a yaw rate as the yaw movement state of a vehicle according to both outputs of both speed sensors Sl, Sr, car velocity detecting means 13 for detecting a car velocity V from the average value of outputs of both speed sensors Sl, Sr, steering gain deciding means 14 for deciding means 14 for deciding the steering gain according to the output of the yaw movement detecting means 3 and the output of the car velocity detecting means 13, the steering angle estimating means 4 for estimating the steering angle of a vehicle according to the steering gain G, and steering angle correcting means 5. According to the steering angle correcting means 5 and the car velocity, the reference yaw rate is decided, and the absolute value of the difference between the reference yaw rate and the yaw rate R is calculated by a subtraction circuit 9. According to the absolute value, the yaw movement is corrected.

Description

Detailed Description of the Invention A8 Object of the Invention (1) Industrial Application Field The present invention relates to a method for controlling yaw motion of a vehicle, which controls yaw motion based on the output of a steering angle sensor attached to a steering wheel. .

(2) Conventional technology Conventionally, the steering angle sensor attached to the steering wheel measures the steering angle value by counting the pulses of a pulser installed in the steering column, and the yaw movement of the vehicle is Control was performed using the detected steering angle value.

(3) Problems to be Solved by the Invention However, there is often a deviation between the steering angle sensor and the actual steering angle when it is attached to the steering wheel. Even so, the neutral point may shift due to some external force while the vehicle is running. If the neutral point shifts in this way, the pulse count value will be reset in response to the neutral point pulse even though the neutral point pulse does not match the neutral point of the actual steering angle, so the count value will not match the appropriate steering angle. As a result, the yaw motion control that is corrected based on the steering angle value becomes uncertain.

The present invention has been made in view of the above circumstances, and the mounting of the steering angle sensor on the steering wheel corrects the output of the steering angle sensor to obtain a steering angle close to the actual steering angle regardless of the state. and based on the almost accurate steering angle, a-
It is an object of the present invention to provide a method for controlling the yaw motion of a vehicle that can control the motion.

B0 Structure of the Invention (1) Means for Solving the Problems To achieve the above objects, the present invention provides a method for controlling yaw motion of a vehicle, which controls yaw motion based on the output of a steering angle sensor attached to a steering wheel. In addition to estimating the turning angle, the output value of the turning angle sensor is gradually corrected within a certain period of time based on the error between the estimated turning angle and the turning angle detected by the turning angle sensor. Features.

(2) Effects According to the method of the present invention, by correcting the output of the steering angle sensor by the error between the estimated steering angle and the estimated steering angle, it is possible to obtain a steering angle close to the actual steering angle, and to maintain a constant steering angle. Due to the gradual correction in time, sudden correction control of the yaw movement is avoided.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. First, in FIG. 1, a speed sensor Sl
! , Sr are individually attached, and these speed sensors Sj2. The output signal of Sr is manually inputted to a turning angle detection device l which is composed of a computer. Further, a steering angle sensor 2 is attached to the steering handle H, and the output of this steering angle sensor 2 is also input to a steering angle detection device 1.

The steering angle detection device 1 is a computer, and includes a yaw motion detection means 3 that detects a yaw ray 1-R as a yaw motion state of the vehicle based on the outputs of both speed sensors 5ffi and Sr;
a vehicle speed detection means 13 that detects the vehicle speed (2) from the average value of the outputs of both speed sensors Sf and Sr; and a steering gain determination means 14 that determines a steering gain based on the output of the yaw motion detection means 3 and the output of the vehicle speed detection means 13. steering angle estimating means 4 for estimating the turning angle δ2 of the vehicle based on the steering gain G and yaw rate (H); The steering angle correction means 5 includes an error detection circuit 6 for detecting an error between the output S of the steering angle sensor 2 and the output 6 of the steering angle estimation means 4, and A correction circuit 7 for correcting the output of the steering angle sensor 2 is provided.

The output of the vehicle speed detection means 13, that is, the vehicle speed, and the turning angle δ′ obtained by the turning angle detection device 1 are manually inputted to the reference yaw rate generation means 8, and the reference yaw rate obtained by the reference yaw rate generation means 8 and The yaw rate R obtained by the yaw motion detection means 3 is input to a subtraction circuit 9. The subtraction circuit 9 calculates the absolute value of the difference between the reference yaw rate and the yaw rate R. That is, the difference between the yaw rate that should be present and the current yaw rate R is determined.

The output of the subtraction circuit 9 is input to the non-inverting input terminal of the comparator 10, and the reference value is input from the terminal 11 to the inverting input terminal of the comparator 10. Therefore, the comparator IO outputs a signal at the 7't level when the difference between the current yaw rate and the current yaw rate R is larger than the reference value, and the output of the comparator IO is The correction means 1 is inputted to a means for correcting the yaw motion, for example, by engine output control.

The steering angle detection device 1, which is a computer, determines the steering angle according to the procedure shown in FIG. First step S
1, it is determined whether the flag F is 1 or not. This flag F is used to indicate whether or not the steering angle is being corrected, and F=1 indicates that the steering angle is being corrected. When F=1 in this first step S1, the process proceeds to the 19th step S19, and when F=O, the process proceeds to the second step S2.

The second step S2 to the tenth step SIO are for determining whether the driving state of the vehicle is in a steady state region suitable for steering angle correction, and when it is determined that the driving state is outside the steady state region. At the 11th step Sll, a timer T is set. This timer T is for counting the time required to determine whether or not the vehicle is in the steady state region, for example, 2 seconds. It is reset each time it is judged.

Each element for determining whether the vehicle is in the steady state region will be explained individually. First, in the second step S2, it is determined whether the vehicle speed ■ is equal to or higher than the lower limit vehicle speed, for example, 8 km/h, and in the third step S3. Then, it is determined whether the vehicle speed ■ is below the upper limit vehicle speed, for example, 501 an/h,
In the fourth step S4, it is determined whether the yaw rate R of the vehicle is within the allowable yaw rate range, for example, 5°/sec. It is determined whether traction control is being performed, and the sixth step S
In step 6, it is determined whether the steering angle S is within the allowable steering angle range. As shown in FIG. 3, this allowable steering angle width is determined according to the vehicle speed (2), and as the vehicle speed (2) increases, the allowable steering angle width is set to be smaller.

In the seventh step S7 and the eighth step S8, the current yaw rate R and steering angle S are changed to the previous average yaw rate RA' and average steering angle SA7, which are set in the 23rd step S23, which will be described later, immediately after finishing the correction. It is determined whether the following is true, and if it is, the 11th step S
Proceed to ll. This is the average yaw rate RA or average steering angle SA when the error correction of the steering angle sensor 2 was performed last time.
The correction operation is started only when the vehicle is traveling straight ahead, in order to obtain a more accurate estimated turning angle.

In the ninth step S9, it is determined whether the yaw rate R is in a constant region. This steady region is set between the regions shown with diagonal lines in FIG.
The center value is the yaw rate R at the time when all the conditions from 1 to 8th step S8 are satisfied for the first time, and the yaw rate R
The steady region (steady turning or straight-ahead state) is determined from the center value of . In a ninth step S9, it is determined whether or not the set time counted by the timer T remains in the steady region for more than two seconds, for example. Also, the 10th step SI
At O, it is determined whether the steering angle S is in the steady region. This steady state region is set in the same manner as the steady state region of the yoke 1-R, and it is determined in the tenth step SIO whether or not the steady state region remains in the steady state region for, for example, two seconds or more.

In this manner, when it is determined in the second step S2 to the tenth step 310 that the operating state of the vehicle is in the steady region, the process proceeds to the twelfth step knob S12, and when it is determined that the driving state is not in the steady region, the process proceeds to the eleventh step.・The timer T is reset at the button Sll.

Twelfth and thirteenth steps 512. In S13, the average value RA of the yaw rate H and the average value S of the steering angle S are calculated using the following equations (1) and (2).

N N N N Here, N is the cumulative number of samplings from the start of calculation of equations (1) and (2), and
2) Equation changes the influence of the current sampling value on the average value depending on the elapsed time from the start of the average value calculation.
A so-called moving average is used. Moreover, the subscript (-3) indicates the previous value.

In the 14th step S14, it is determined whether or not the timer T has finished counting the set time. If the time T for determining the steady region has elapsed, the flag F is set to 1 in the 15th step S15. do.

The next 16th step S16 shows processing in the steering angle estimating means 4, and the estimated steering angle δ is obtained by dividing the yaw rate average value RA by the steering gain G. That is, δr=RA/G, G=G, -C;'
It is R. Here, G is a reference gain that is determined depending on the vehicle speed (2) as shown in FIG. 5, and is theoretically determined by the following equation (3).

n! ! ,・(1+-V") Here, n is the steering gear ratio, i is the wheel base, and K is the stability factor. Also, G' is the yaw rate R.
This is a correction coefficient for reducing the steering gain when the steering gain increases. In other words, when the vehicle speed is kept constant, the relationship between the yaw rate and the steering angle is as shown in Figure 6.The lateral acceleration applied to the vehicle is determined from the yaw rate R and the vehicle speed, and the influence of this lateral acceleration is Since the load shift of the vehicle and the compliance change of the suspension occur from Theoretical value of gain G. By correcting this, the steering gain is approximated to the actual steering gain while the vehicle is running.

In the seventeenth step 517, the error ε1 is calculated. That is, the difference (
ε1=δPSA) is calculated. Furthermore, in the next 18th step 31B, the following calculation is performed.

Δε−ε, /N, ... (4) In this equation (3), N is N, -'rc/T. .

As shown in FIG. 4, Tc is a time set for correcting the steering angle value after determining the steady state region, and is set to, for example, 1 second. Therefore, Equation (4) is expressed as the correction amount Δε for each loop in the processing procedure shown in FIG.
This is what we seek.

In the nineteenth step 319, the correction value ε. is the next (5)
Required by Ni.

ε. =ε. +Δε...(5) Furthermore, in the 20th step S20, it is determined whether the time Tc set for correcting the steering angle value has elapsed, and if the time Tc has not elapsed, the process returns to the 24th step S24. If so, the process advances to the 21st step S21. In the 21st step S21, the flag F is set to 0, and in the 22nd step S22, the timers T, , Tc are reset, and in the 23rd step S23, the yaw rate average value RA is set to RA'
Also, the steering angle average value SA is set to SA'.

In the twenty-fourth step 324, the steering angle δ' output from the steering angle detection device 1 is calculated according to the following equation (5).

δ′=S+ε. ...(6) Next, to explain the operation of this embodiment, in the processing procedure shown in FIG.
In step SIO, it is determined whether or not the vehicle is in the steady region in order to correct the steering angle S detected by the steering angle sensor 2, and when it is determined that the vehicle is in the steady region, in step S15 Set flag F to 1 and proceed to the next step.

After it is determined that the vehicle is in a steady driving state as described above, the steps S16 to 18 are carried out in steps S16 to 31.
In step 8, the correction amount Δε per processing loop is calculated. That is, in the 16th stenops S16, the estimated steering angle δ2 is obtained by dividing the yaw rate RA by the steering gain G, and the error ε between this estimated steering angle δ and the steering angle average value SA based on the output of the steering angle sensor 2 is The error ε1 is obtained in the 17th step 317, and the correction amount Δε per processing loop is
obtained in step 318. ``The 16th step S16 to the 18th step 318 are executed only in the first processing loop after it is determined that the driving state of the vehicle is in the steady region. The process moves from step S1 to the nineteenth step S19.

Here, with reference to FIG. 7, if it is assumed that there is an error of ε1 between the steering angle S detected by the steering angle sensor 2 and the estimated steering angle δ2 by the steering angle estimating means 4, then once The correction value ε is obtained by adding the correction amount Δε for each processing loop. is added to the steering angle S, and the set time T.

By the time , the output δ' from the steering angle detection device l is corrected to the estimated steering angle δ. That is, the difference between the detected turning angle S and the estimated turning angle δ gradually becomes O by the time the set time Tc elapses, and by making redundant corrections in this way, Yaw motion correction means 12
It is possible to avoid sudden correction control at , and it is possible to make gradual corrections to the yaw motion.

C1 Effects of the invention As described above, according to the present invention, the turning angle is estimated, and the output of the turning angle sensor is calculated based on the error between the estimated turning angle and the turning angle detected by the turning angle sensor. Since the value is gradually corrected within a certain period of time, installing the steering angle sensor on the steering wheel makes it possible to obtain an extremely accurate turning angle regardless of the condition, and the correction can be made within a certain period of time. By performing the control gradually, sudden correction control of the yaw movement is avoided.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a block diagram showing the overall configuration, FIG. 2 is a flowchart showing the processing steps, and FIG. 3 is a diagram showing the setting state of the allowable steering angle width. ,
Figure 4 is a diagram showing the allowable range for determining the stable state of yaw rate and steering angle, Figure 5 is a characteristic diagram of the standard steering gain, and Figure 6 is the relationship between yaw rate and steering angle when the vehicle speed is constant. FIG. 7 is a diagram for explaining the steering angle correction procedure. 2... Steering angle sensor H... Steering handle Figure 7 Figure 5 Vehicle speed Figure 6 Yaw rate

Claims (1)

[Claims] In a vehicle yaw motion control method that controls yaw motion based on the output of a steering angle sensor attached to a steering wheel, a steering angle is estimated, and the estimated steering angle and the detected steering angle by the steering angle sensor are calculated. A method for controlling yaw motion of a vehicle, characterized in that the output value of a steering angle sensor is gradually corrected within a certain period of time based on an error between the steering angle sensor and the steering angle sensor.