JPH0699833A - Steering angle detecting device - Google Patents

Abstract

PURPOSE:To obtain a steering angle detecting device capable of detecting an absolute steering angle of a steering wheel even immediately after turning on an ignition switch. CONSTITUTION:With regard to a steering angle detecting device detecting an absolute steering angle of a steering wheel base on its own neutral position, an absolute steering angle (phi) at the moment an ignition switch is turned off is memorized and, when the ignition switch is turned on the next time, the absolute steering angle (thetainc (t)) is detected on the basis of the memorized value. When the neutral position is compensated, an absolute steering angle (thetas) is detected on the basis of the neutral position (thetanincm). Because the steering wheel is not caused to be rotated while the ignition switch is turned off, the value in memory and the steering angle of the steering wheel while the ignition switch is turned on coincides with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to detection of a steering angle of a steering wheel.

[0002]

2. Description of the Related Art The steering angle of a steering wheel is usually detected by a steering angle sensor which is an incremental rotary encoder. The incremental steering angle sensor detects a distance (hereinafter, abbreviated as a relative steering angle) between the position of the steering wheel at the time of detection and the position of the steering wheel at the time of turning on the ignition switch. for that reason,
The distance between the steering wheel position and the steering wheel neutral position at the time of detection (hereinafter,
In order to detect the absolute steering angle), it is necessary to correct the neutral position of the steering angle sensor.

As an example thereof, a steering angle detecting device disclosed in Japanese Patent Laid-Open No. 1-226476 is known. In the steering angle detecting device described in this publication, the neutral position of the steering angle sensor is corrected to the output value of the steering angle sensor during straight traveling based on the steering wheel being in the neutral position during straight traveling, and The steering angle of the steering wheel is detected based on the corrected neutral position. The steering angle detected after the neutral position is corrected is the absolute steering angle.

[0004]

However, the device described in the above publication has a problem that the absolute steering angle cannot be detected immediately after the ignition switch is turned off and then the ignition switch is turned on. there were. This is because the neutral position of the steering angle sensor cannot be corrected unless the vehicle travels straight.

In the present invention, the ignition switch is turned on.
The purpose of the invention is to obtain a device that can detect the absolute steering angle of the steering wheel immediately after the setting.

[0006]

In order to solve this problem, a steering angle detecting device according to the present invention, as shown in FIG. 1, is a steering wheel detecting a steering angle of a steering wheel with reference to its own neutral position. The steering angle detecting means 1 is based on the state of the steering angle detecting means 1 and the steering device including the steered wheels.
Correction means 2 for correcting the neutral position of the ignition switch, the memory 3 for holding the stored contents even when the ignition switch is in the OFF state, and the correction means 2 is operated at least once while the ignition switch is in the ON state. The steering angle detection means 1 stores the detected steering angle in the memory 3 at the moment when is turned off, and sets the steering angle stored in the memory 3 as an initial value immediately after the ignition switch is turned on.
And a control means 4 for starting the detection of the steering angle.

[0007]

In the steering angle detecting device of the present invention, the steering angle detecting means 1 detects the steering angle of the steering wheel based on its own neutral position. The detection value of the steering angle detection means 1 at the moment when the ignition switch is turned off, that is, the absolute steering angle of the steering wheel is stored in the memory 3 by the control means 4. The stored contents of the memory 3 are not lost even when the ignition switch is in the OFF state. Next, immediately after the ignition switch is turned on and until the neutral position of the steering angle detecting means 1 is corrected by the correcting means 2, the control device 4 causes the steering angle detecting means 1 to set the steering angle of the steering wheel. The value stored in the memory 3 is detected as an initial value. Since the steering wheel is hardly rotated when the ignition switch is OFF, the steering angle of the steering wheel when the ignition switch is ON matches the steering angle stored in the memory 3. The steering angle of the steering wheel detected by the steering angle detecting means 1 with the steering angle stored in the memory 3 after the ignition switch is turned on as an initial value can be considered as an absolute steering angle. . However, the correction means 2
After the neutral position of the steering angle detecting means 1 is corrected by the steering angle detecting means 1, the steering angle detecting means 1 detects the steering angle of the steering wheel based on the corrected neutral position.

The neutral position of the steering angle detecting means 1 is
It is corrected based on the state of the steering device including the steered wheels.
For example, the neutral position is corrected so that the steering angle of the steering wheel estimated from the speed difference between the left and right steered wheels and the detection value by the steering angle detection means 1 are substantially equal to each other, or the neutral position becomes the detection value when traveling straight ahead. It will be corrected.

[0009]

According to the steering angle detecting device of the present invention, the absolute steering angle of the steering wheel can be detected even immediately after the ignition switch is turned on.

If the steering angle detection device of the present invention is used in a vehicle control device in which traveling control is performed based on the steering angle of the steering wheel, the ignition switch is turned on.
Immediately after setting to N, the traveling control based on the absolute steering angle can be performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the steering angle detecting device of the present invention is used in a vehicle control device mounted on a four-wheel drive and four-wheel steering vehicle will be described in detail with reference to the drawings. Figure 2
In the vehicle control device, the CPU, the ROM, and the R
Steering angle detection device 12 including AM, input part, output part, bus, etc., rear wheel steering angle control device 14, start control device 16, target yaw rate following control device 18, vehicle speed calculation device 20
Each of these devices 12 to 20 is provided with an input unit, a wheel speed sensor 30 to 36 for detecting the rotation speed of each wheel, an accelerator opening sensor 38, and a brake for detecting whether or not the brake pedal is depressed. A switch 40, a yaw rate sensor 42, a steering angle sensor 44 for detecting the rotation angle of the steering wheel 43, etc. are connected, and a rear wheel steering actuator 50, a differential limiting actuator 52 are connected to the output section.
Etc. are connected.

Also, the memory 5 having a backup battery
6 is provided and is connected to the input section and the output section of the steering angle detection device 12. This memory 56 is stored even when the ignition switch is off.

The memory 56 always stores the steering angle detecting device 12
The output value θs of is supplied and rewritten. Therefore, when the ignition switch is turned off, the output value at that moment is held. Here, the data stored when the ignition switch is turned off is φ.

The vehicle control device detects the absolute steering angle θs of the steering wheel 43 based on the output values of the sensors 30 to 42, the stored value of the memory 56, etc., and controls the actuators 50 and 52 based on the absolute steering angle θs. The driving control of the vehicle is performed by driving.

The steering wheel 43 is provided with a steering lock device (not shown) so that it cannot be rotated while the ignition switch is in the OFF state.

The steering angle sensor 44 is an incremental type rotary encoder, and includes a slit plate that rotates integrally with the steering wheel 43, and two photo interrupters fixed to the vehicle body and each having a light emitting diode and a light receiving diode. I have it. A light blocking state and a light transmitting state which are alternately generated by the rotation of the slit plate are detected by the HIGH signal and the LOW signal of the light receiving diode. As shown in FIGS. 3 and 4, the two photo interrupters are provided with a phase difference of ¼ cycle, and right rotation and left rotation are distinguished.

When the steering wheel 43 is rotated to the right, the SS1 signal at the rising edge of SS2 is always LOW as shown in FIG. 3, and when it is rotated to the left, SS2 is shown as shown in FIG. The signal of SS1 at the rising edge of is always HIGH. Therefore, the rotation angle in both the positive and negative directions can be obtained by counting the rising signal of SS2 with the positive signal when the SS1 signal is HIGH and the negative signal when the SS1 signal is LOW. The slit interval is 2.25 deg, the right rotation is negative and the left rotation is positive.

Further, in the incremental type steering angle sensor 44, since the counting is started with the rotation of the steering wheel 43 from the time when the ignition switch is turned on, the output value θ of the steering angle sensor 44 is
x represents the distance between the position of the steering wheel 43 at the time of detection and the position of the steering wheel 43 at the time when the ignition switch is turned on, and is not an absolute steering angle.

Next, the actuators 50 and 52 will be described. In the present embodiment, the rear wheel steering actuator 50 is a servo valve of a rear steering mechanism (not shown), and is controlled by the rear wheel steering angle control device 14. The rear steering mechanism steers the rear wheels and is provided with a hydraulic cylinder and a servo valve for controlling the flow of hydraulic fluid into and out of the hydraulic chamber. The servo valve is connected to a hydraulic pressure source (not shown), and by controlling the servo valve, hydraulic fluid is caused to flow into and out of the hydraulic chamber of the hydraulic cylinder, and the rear wheels are steered.

In the present embodiment, the differential limiting actuator 52 is a hydraulic pressure control valve for controlling the hydraulic pressure of a center differential differential limiting device (not shown). The starting control device 16 is used at the time of starting and the target yaw rate tracking is performed at the time of running. Each is controlled by the control device 18.
The differential limiting device limits the differential between the front and rear propeller shafts and is provided with a hydraulic control valve. A hydraulic pressure source is connected to the hydraulic pressure control valve, and the magnitude of the hydraulic pressure of the differential limiting device is controlled by controlling the hydraulic pressure control valve. When the fluid pressure is high, the limiting amount is large, and the starting performance is good, while when the fluid pressure is low, the limiting amount is small,
Good turning performance.

The vehicle speed calculating unit 20 calculates the left and right front wheel speeds WR and WL based on the output values of the wheel speed sensors 30 to 36.
, Front-rear average wheel rotation speeds Nf, Nr, estimated vehicle body speed V, vehicle body acceleration, etc., and their output values V, WR, WL, Nf, Nr etc. are detected by the steering angle detection device 12,
Rear wheel steering angle control device 14, target yaw rate tracking control device 1
It is supplied to 8th grade.

The steering angle detecting device 12 includes a steering angle sensor 44.
Of the steering wheel 43 based on the corrected neutral position and the like.
The absolute steering angle θs of is detected. The ROM of the steering angle detection device 12 stores a program and the like represented by the flowchart of FIG.

Rear wheel steering angle control device 14 and start control device 1
6. The target yaw rate tracking control device 18 uses the actuators 50, 52 based on the absolute steering angle θs of the steering wheel 43 detected by the steering angle detection device 12 and the like.
To control the traveling of the vehicle. The ROM of the rear wheel steering angle control device 14 stores the program represented by the flowchart of FIG. 8 and the tables represented by the graphs of FIGS. 11 and 12, and the ROM of the start control device 16 includes:
The program represented by the flowchart of FIG. 9 and FIG.
The tables represented by the graphs 3 and 14 are stored, and the ROM of the target yaw rate following control device 18 stores the program represented by the flowchart of FIG. 10 and the tables represented by the graphs of FIGS. .

Further, since multiplex communication means is used for transmitting data among the respective sensors, the control device and the actuator, it is possible to transmit a plurality of data using one connecting means.

First, the detection of the absolute steering angle θs will be described with reference to the flowchart shown in FIG. This routine is constantly executed, and the absolute steering angle θs of the steering wheel 43 is detected. The absolute steering angle θs of the steering wheel 43 is obtained based on the neutral position θninc after the correction of the neutral position is completed, but if the correction is not completed, the data φ stored in the memory 56 is stored. Is calculated based on. In addition, the correction flag F has the ignition switch set to O.
When it is set to FF, it is reset, and it is set when the correction of the neutral position is completed. After being set once, the neutral position remains the same no matter how many times it is corrected again.

In step 1 (hereinafter abbreviated as S1; the same applies to other steps), it is determined whether the correction flag F is set. If the correction flag F is not set, NO is determined and the processing from S3 is executed, but if the flag F is set, YES is determined and the previous correction flag F is set in S2. It is determined whether or not the set time has elapsed since the operation. When the set time has elapsed, YES is determined and S3 and subsequent steps are executed, but when NO is determined, S3 to S5 are bypassed and S6 and subsequent steps are executed.

That is, the ignition switch is turned on.
Immediately after being set to, the correction flag F is not set, so that it is determined to be NO in S1 and the neutral position is corrected in S3. Even after the neutral position is once corrected, after the set time elapses, YES is determined in both S1 and S2, so the neutral position is corrected. The correction of the neutral position in S3 will be described later.

In S4, it is determined whether or not the correction in S3 is completed. If it is determined to be YES, the correction flag F is set and the timer is reset in S5. If NO is determined, the value of the correction flag F remains unchanged. Since it takes at least 5.14 s to complete one execution of S3, the step of S4 is provided so that the steering angle is detected during that time.

At S6, it is determined whether the correction flag F is set. If NO is determined, in S7, the absolute steering angle θs of the steering wheel 43 is a value obtained by adding the value φ stored in the memory 56 to the output value θx (t) of the steering angle sensor 44 (θx (t ) + Φ) is the low-pass filtered value (θinc). As described above, since the steering wheel 43 has the steering lock device, the steering wheel 43 is not rotated while the ignition switch is off. Therefore, the actual steering angle of the steering wheel 43 when the ignition switch is turned on is the absolute steering angle φ stored in the memory 56.
Is almost the same (see FIG. 5).

If YES is determined, in S8, the absolute steering angle θs is a value θinc obtained by low-pass filtering the absolute steering angle (θx (t) + φ) as shown in FIG.
The value obtained by subtracting the neutral position θninc _m from the above (θinc − θninc _m ) is used. Further, as described above, in this embodiment, the neutral position is corrected a plurality of times. Neutral position θni
If nc is obtained once, it may be the same value until the ignition switch is turned off, but the alignment shifts due to deformation of the support member that supports the axle due to heat, aging, etc. This is because the neutral position may shift.

Next, the correction of the neutral position in S3 will be described with reference to the block diagram shown in FIG. The neutral position θninc is obtained so that the average value <θc> of the absolute steering angle of the steering wheel 43 and the average value <Θ *> of the steering angles obtained by converting the front wheel steering angle by the steering gear ratio match.

In block 1 (hereinafter abbreviated as B1), the low-pass filtered absolute steering angle θinc
((Θinc (t-Δt) + θ (t)) / 2) is input. That is, when the ignition switch is turned on and executed immediately, the value obtained in S7 is input, and when executed after the neutral position is corrected, the value obtained in S8 is input in a timely manner. Is done. The input value is adjusted in steering angle phase by the transfer function {1 / (TS + 1)}. That is, the calculation is performed based on the following formula, and θi (n) = (θinc + 19 × θi (n-1)) / 20 data θi (n) is output. In B2, the data θi
(n) is input, and the filtering processing is performed on the input data θi (n) that satisfies the condition A described later. The equation θc (n) = (θi (n) + 3 × θc (n-1)) / 4 is calculated, and the data θc (n) is output. Next, B3
, The data θc (n) is input, and the average of the input data θc (n) satisfying the condition B described later is performed 256 times, and the average value of the steering angle of the steering wheel 43 <θc (n )> Is required.

Since data is input to B1 every 5 ms, data is output from B1 and B2 every 5 ms and averaged 256 times at B3, so that all input data satisfy the conditions A and B. Assuming that B3
Therefore, data is output every 1.28 s (5 ms × 256).

On the other hand, at B4, the left and right front wheel speeds WR, WL
Is input, and the steering angle Θ of the steering wheel 43 is calculated based on the following equation. Θ = (N ・ L / H) ・ (WR-WL) / V ・ (1 + K ・
V ² ) ・ 180 / π N: Steering gear ratio L: Wheel base H: Front tread WR: Right front wheel speed WL: Left front wheel speed K: Stability factor V: Average front wheel speed (WR + WL) / 2 In the above formula Is calculated from the front wheel speed difference,
The steering angle Θ of the steering wheel 43 is obtained by multiplying the front wheel steering angle by the steering gear ratio.

In B5 and B6, like B2 and B3,
The average values of the steering angles Θ * (n) and <Θ * (n)> are obtained.
However, the calculation of B4 is performed every 20 ms, and the average value of the steering angle <Θ * (n)> is the average value of the data Θ * (n) of 64 times. As a result, all the input data are conditions A and B.
Assuming that the above condition is satisfied, from B6, 1.28 s (2
Data is output every 0 ms × 64).

The condition A includes all of the following matters. 30 km / h ≤ (WR, WL) ≤ 120 km / h Absolute value of steering speed dθs / dt ≤ 2.8 rad / s Anti-skid control inactive Brake switch 40 output value OFF No abnormality in wheel speed system This is a so-called normal running state such as when the rotational angular velocity is not high or when braking is not being performed. The condition B is that the data θc (n), Θ *
The absolute value of (n) is 100 deg or less. That is, the sharp turn state is removed.

Average value output from B3, 6 <θc (n)
> And the average value <θ * (n)> θN (<θc (n)>-<
[Theta] * (n)>) is obtained and input to B7, and the average value of four times is taken. As a result, 5.12 s (1.
The average value <θ N (n)> is output every 28s × 4). Next, in B8, the average value <θ N (n)> is input, and for the average value <θ N (n)> that satisfies the following condition C, the expression θ N (n) ′ = (<θ N (n)> The calculation is performed based on> + 7 × θ N (n-1) ') / 8, and the data θ N (n)' is output. In B9, the inclination of the input data θ N (n) ′ is limited, and the data θ N (n) ′ is set to the neutral position θ ninc. Here, the tilt limitation is the data θN (n-1) ′ obtained last time and the data θN obtained this time.
The absolute value of the difference from (n) ′ should not exceed 11.25 deg. Condition C is the average value obtained this time <
The absolute value of the difference between θ N (n)> and the average value <θ N (n-1)> obtained last time is less than 87.75 deg.
According to the condition C, data with large variations are removed.

As described above, the portion of the steering angle detecting device that executes S3 constitutes the neutral position correcting means, and the portion of the steering angle sensor 44 and the steering angle detecting device 12 that executes S7 and 8 is the steering angle detecting means. And the part that also executes S6 constitutes the control means.

Next, the vehicle traveling control executed based on the absolute steering angle θs obtained by the steering angle detecting device 12 will be described. Here, the rear wheel steering angle control and the hydraulic control of the center differential differential limiting device are performed, but in both cases, the control closer to the stable side is performed before the neutral position is corrected, After the correction is completed, control for improving the turning performance is performed.

First, the rear wheel steering angle control will be described with reference to the flowchart of FIG. This routine is 20ms
It is executed every time. The estimated vehicle speed V, the absolute steering angle θs, and the yaw rate γ are read in S20, and the value of the correction flag F is referred to in S21. In S22 to S24, the gains K1 and K5 are obtained from the estimated vehicle speed V based on FIGS. 11 and 12, and the rear wheel steering angle δr is calculated based on them, and the rear wheel steering angle is set to δr. A servo valve as the steering actuator 50 is driven.

As is apparent from FIGS. 11 and 12, when the correction flag F is 0 (reset), the gain K1 is set to 0 regardless of the estimated vehicle body speed V, and the rear wheels have the same yaw rate γ. It is steered in the direction. Therefore, an understeering tendency occurs during turning, and control is performed closer to the stable side. If the flag F is 1 (set),
At low speeds, the rear wheels are steered in a phase opposite to the absolute steering angle θs, improving the turning performance and enabling a small turn.

Next, the starting control will be described with reference to the flowchart of FIG. This routine is always executed, but in S30, it is determined whether or not the start control flag FH is set, and if NO is determined, virtually nothing is executed, and only if YES is determined. Substantial control is provided. The vehicle speed is 0 for the start control flag FH.
It is set when it becomes, and is reset when the start control is completed.

In S31, it is determined whether or not the correction flag F is set, and if NO is determined, S3
2, the gain K3 is set to K0, and if YES is determined, the absolute steering angle θs is read in S33 and S34, and the gain K3 is read from the table of FIG.
3 is required. Immediately after the ignition switch is turned ON, the determination in S30 is YES and the determination in S31 is NO. However, if the vehicle stops after the correction is completed, it is determined to be YES in both S30 and 31. It

In S35, the output signal of the brake switch 40 is read, and it is determined whether or not the output signal is ON. If it is ON and the vehicle is stopped, YES is determined, and S31
Returned to. When the vehicle is switched to the start state when it is OFF, it is determined to be NO, and in S36 to 39, the hydraulic pressure value of the differential limiting device is controlled. That is, the accelerator opening A is read, the hydraulic pressure value is obtained from FIG. 14 based on the accelerator opening A and the gain K3, and the hydraulic pressure control valve as the actuator 52 is driven so as to have the hydraulic pressure value. Of. When the start control is completed, the start control flag FH
Is reset.

As is apparent from FIGS. 13 and 14, when the correction flag F is 0 (reset), the hydraulic pressure is increased to suppress the speed difference from occurring and the acceleration performance is improved. Flag F
Is set to 1 (set), the hydraulic pressure is lowered as the steering angle increases, and the turning performance is improved. Further, the hydraulic pressure is increased with the accelerator opening, and the acceleration performance is improved.

Next, the target yaw rate follow-up control will be described with reference to the flowchart of FIG. Although this routine is executed every 20 ms, it is determined in S50 whether the start control flag FH is set.
When the flag FH is set and it is determined to be YES, practically nothing is executed, and only when it is determined to be NO, substantial control is performed. When the flag FH is set, the hydraulic pressure of the differential limiting device is controlled by the start control device, so that this routine is not substantially executed.

In S51 and S52, the front and rear average wheel rotational speeds Nf and Nr, the absolute steering angle θs, the vehicle body speed V, the yaw rate γ, etc. are read, and the absolute value ΔNFR of the difference between the front and rear average wheel rotational speeds is calculated. In steps S53 to S56, the value of the correction flag F is referred to, the value of the gain K4 is calculated based on the value, the target yaw rate γ0 is calculated, and the difference between the target yaw rate γ0 and the actual yaw rate γ is multiplied by the yaw rate γ. Thus, the yaw rate deviation related amount Δγ is calculated. In S57 and S58, the gain K2 is obtained from the yaw rate deviation related amount Δγ based on FIG. 16, and the hydraulic pressure P is obtained from FIG. 17 based on ΔNFR calculated in S52. In S59, the hydraulic pressure value PCD of the differential limiting device is obtained by multiplying these, and in S60, the hydraulic control valve as the differential limiting actuator 52 is driven so as to obtain the hydraulic pressure value PCD.

As is apparent from FIGS. 15 to 17, when the correction flag F is 1 (set), the target yaw rate γ 0 is a large value, and when it is 0 (reset), it is a small value. Further, the fact that the yaw rate deviation related amount Δγ is positive means that the actual yaw rate γ is the target yaw rate γ 0
It means that the vehicle is running short of the target yaw rate and that being negative means that the vehicle is turning beyond the target yaw rate γ0. Therefore, in the former case, the vehicle is running understeer, and in the latter, the vehicle is running oversteer. When the yaw rate deviation-related amount Δγ is negative and the vehicle is running with a slight tendency to oversteer, the gain K2 is set to a large value and spinning is avoided. Also, for the same reason, the hydraulic pressure is increased as the difference between the front and rear average wheel speeds is increased.
It is controlled to avoid spin.

As described above, in the present control device, the hydraulic pressure of the differential limiting device is controlled so that there is no difference between the target yaw rate γ0 and the actual yaw rate γ, but the correction flag F is set. If the target yaw rate γ
0 is decided a little.

As described above, in the present embodiment, since the absolute steering angle θs at the moment when the ignition switch is turned off is stored in the memory 56, the absolute steering angle θs is calculated immediately after the ignition switch is turned on. The steering angle can be detected, and the vehicle traveling control can be satisfactorily performed based on the detected steering angle.

Further, as in the above embodiment, by switching the control state before and after the neutral position is corrected, it is possible to perform control so as to improve the turning performance while considering the stability.

In the above embodiment, as shown in FIG. 5, the neutral position is corrected by steering angle θinc (θ
Although it is performed based on x (t) + φ), it may be performed based on the output value θx (t) of the steering angle sensor 44, the absolute steering angle θs (t), or the like. The detection in that case is performed as shown in FIG. 18 in the former case and as shown in FIG. 19 in the latter case. In addition, the steering angle θ (t, θninc in FIG.
_m-1 ) is an absolute steering angle obtained with reference to the neutral position in the immediately preceding section. That is, the correction of the neutral position in the section B _m is the performed on the basis of the absolute steering angle corrected by the neutral position θninc _m-1 obtained in the section B _m-1.

In the above embodiment, the steering wheel 43 is provided with the steering lock device so that it cannot be rotated while the ignition switch is in the OFF state. However, the steering wheel 43 is provided with the steering lock device. It is not essential to be present. When the steering lock device is not provided, the actual steering angle of the steering wheel 43 at the time when the ignition switch is turned on and the steering angle of the steering wheel 43 at the moment when the ignition switch is turned off last time (stored in the memory 56). In some cases, the absolute steering angle detected immediately after the ignition switch is turned on may be a value including a large error, because the data may not match the stored data φ). Therefore, the neutral position obtained based on the absolute steering angle becomes a large value, or a large difference occurs between the neutral position θninc ₁ obtained at the first time and the neutral position θninc ₂ obtained at the second time. To do. However, since the value of the neutral position converges to a certain value as the number of corrections increases, the error of the absolute steering angle also decreases. On the other hand, if the neutral position is corrected based on the absolute steering angle θs in the previous section, as shown in FIG. 19, the neutral position will be converged more quickly.

Further, when the value of the neutral position obtained as described above is large and it is estimated that the absolute steering angle includes a large error, the set time in S2 is shortened and the neutral correction is frequently performed. You may want to be told. By doing so, the time until the neutral position converges can be shortened, and the error in the absolute steering angle can be reduced early. Also, the output value of B3 <θc>
And the output value <Θ *> of B6 is larger than the set value, the set time in S2 may be shortened. Further, as described above, this set time may be changed when a certain condition is satisfied, or may always be the same value.

Further, in the above embodiment, the absolute steering angle θs at the moment when the ignition switch is turned off is stored in the memory 56, but as shown in FIG. 20, at the moment when the ignition switch is turned off. The value θinc ′ and the neutral position θninc ′ at that time may be stored. That is, a value for obtaining the absolute steering angle may be stored instead of the value of the absolute steering angle θs itself.

Further, in the above embodiment, the neutral position is corrected so that the steering angle of the steering wheel 43 and the steering angle obtained from the front wheel steering angle match, but a straight traveling determination means for determining a straight traveling state is provided. Provided,
As a result, the value of the steering angle sensor when it is determined that the steering device is in the straight traveling state may be corrected to the neutral position.

Although the steering angle sensor is of the incremental type in the above embodiment, it may be of the absolute type or the like. Even in the case of an absolute type steering angle sensor, the position of absolute 0 shifts due to the shift of alignment, etc., so it is effective to correct it in the same manner as the above embodiment.

Further, in the above embodiment, the vehicle traveling control state is changed before and after the neutral position is corrected, but it is not essential to change the traveling control.
The method of detecting the steering angle may be changed before and after the correction.

Further, although the vehicle control device in the above embodiment is provided with a plurality of control devices, it may be one control device having a plurality of programs.

Although not specifically exemplified, the present invention can be carried out in various modified and improved modes without departing from the scope of the claims based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a block diagram conceptually showing the structure of the present invention.

FIG. 2 is a block diagram showing the structure of a vehicle control device that is an embodiment of the present invention.

FIG. 3 is a diagram showing a state of an output signal of the steering angle sensor of the above embodiment.

FIG. 4 is a diagram showing another state of FIG.

FIG. 5 is a diagram showing a steering angle detection state of the steering angle detection device of the above embodiment.

FIG. 6 is a flow chart showing a program stored in a ROM of the steering angle detecting device of the above embodiment.

FIG. 7 is a block diagram showing an execution in S3 of the above flowchart.

FIG. 8 is a flowchart showing a program stored in a ROM of the rear wheel steering angle control device in the above embodiment.

FIG. 9 is a flowchart showing a program stored in a ROM of the generation control device of the above embodiment.

FIG. 10 is a flowchart showing a program stored in a ROM of the target yaw rate tracking control device of the above embodiment.

FIG. 11 is a graph showing a table stored in a ROM of the rear wheel steering angle control device.

FIG. 12 is a graph showing a table stored in a ROM of the rear wheel steering angle control device.

FIG. 13 is a graph showing a table stored in a ROM of the start control device.

FIG. 14 is a graph showing a table stored in a ROM of the start control device.

FIG. 15 is a graph showing a table stored in a ROM of the target yaw rate tracking control device.

FIG. 16 is a graph showing a table stored in a ROM of the target yaw rate tracking control device.

FIG. 17 is a graph showing a table stored in a ROM of the target yaw rate tracking control device.

FIG. 18 is a diagram showing a steering angle detection state of a steering angle detection device according to another embodiment of the present invention.

FIG. 19 is a diagram showing a steering angle detection state of a steering angle detection device according to another embodiment of the present invention.

FIG. 20 is a diagram showing a steering angle detection state of a steering angle detection device according to another embodiment of the present invention.

[Explanation of symbols]

 12 Steering angle detection device 44 Steering angle sensor 56 Memory

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B62D 113: 00 137: 00

Claims (1)

[Claims] 1. A steering angle detecting means for detecting a steering angle of a steering wheel with reference to its own neutral position, and a correcting means for correcting the neutral position of the steering angle detecting means based on a state of a steering device including a steering wheel. A memory that retains stored contents even when the ignition switch is OFF, and the steering means at the moment when the ignition switch is turned OFF by operating the correction means at least once while the ignition switch is ON. Control for storing the detected steering angle of the angle detection means in the memory, and for making the steering angle detection means start detection of the steering angle with the steering angle stored in the memory as an initial value immediately after the ignition switch is turned on. And a steering angle detecting device.