JP2552357B2 - Vehicle dynamic characteristics control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention provides a steering angle absolute value, such as an auxiliary steering control system or an active suspension control system for auxiliary steering at least one of front wheels and rear wheels during steering of front wheels. The present invention relates to a vehicle dynamic characteristic control device that optimally controls vehicle characteristics such as yaw rate, lateral acceleration, and vehicle body roll included in control information.

(Prior Art) An example of such a preceding rear wheel steering control system (an example of a vehicle dynamic characteristic control device) is a system proposed by the present applicant in Japanese Patent Application No. 62-330281.

The rear wheel steering control system determines the rear wheel steering angle theta _R based on the front-wheel steering angle theta _F and the vehicle speed V, and the rear wheels to the front wheels steered in-phase or reverse-phase, for example, front-wheel steering vehicle (2WS
Compared to a car, it improves steering stability by suppressing the vehicle's lateral slip angle, and improves responsiveness by increasing the yaw rate rise.

(Problems to be Solved by the Invention) Such a rear-wheel steering control system includes a front-wheel steering angle θ _F.
Because the control information is used as the control information, a steering wheel steering angle sensor for detecting the steering wheel steering angle θ, a steering wheel neutral position sensor for detecting the neutral position of the steering wheel within a predetermined steering angle range, and a neutral steering angle estimation value θ for setting the vehicle straight ahead. _It requires a neutral steering angle estimated value calculation circuit for calculating _C, and a front wheel steering angle calculation circuit for obtaining a front wheel steering angle θ _F (steering angle absolute value) from the steering wheel steering angle θ and the neutral steering angle estimated value θC.

Therefore, when the power of the rear wheel steering control unit is turned off by the ignition switch etc. and then turned on again, the neutral steering angle estimated value θ _C is newly calculated by the neutral steering angle estimated value calculation circuit, and When the rudder control is started, the start of the rear wheel steering control is significantly delayed by waiting for the end of the calculation of the neutral steering angle estimated value θ _C.

That is, in the neutral steering angle estimated value calculation circuit, at least when the steering wheel neutral position is detected, and the steering angle is within the range of the steering angle (hereinafter referred to as “corrected steering angle”) by the steering operation intended for straight traveling of the driver. Since the neutral steering angle estimated value θ _C is calculated when the inside state continues for a predetermined traveling distance, the neutral steering angle can be neutralized for a considerably long time when traveling on a curved road or a city road where the frequency of turning operation is high. The steering angle estimated value calculation condition is not satisfied, and during that period, the rear wheel steering control is not performed at all.

Therefore, when the power of the rear wheel steering control unit is turned off and then turned on again, for example, there is a plan to immediately start the rear wheel steering control using a preset neutral steering angle or the like. The handle is rotated from when the power is turned off until it is turned on, and the handle is rotated 360
There is a possibility that the steering wheel neutral position sensor may erroneously detect the steering wheel neutral position at the position where the steering wheel is turned.

That is, the steering wheel neutral position sensor detects, for example, an arc-shaped slit in the range of about 20 ° formed on a disk-shaped sensor disk that rotates with the operation of the steering wheel by an optical sensor that uses light passage blocking. Therefore, even if the handle is turned 360 degrees, it will be detected as the handle neutral position.

The present invention has been made in view of the above-mentioned problem, and in a vehicle dynamic characteristic control device that includes an absolute steering angle value in control information, achieves early control start timing and erroneous steering wheel neutral position while maintaining high control accuracy. The challenge is to achieve both detection and prevention.

(Means for Solving the Problems) In order to solve the above problems, in the vehicle dynamic characteristic control device of the present invention, when the power is turned off and then turned on again, the steering angle detection value is within a range of less than ± 180 degrees. When the neutral position is detected, the dynamic characteristic control is started by using the previously stored neutral steering angle estimated value.

That is, as shown in the claim correspondence diagram of FIG. 1, at least steering wheel steering angle detecting means a for detecting the steering wheel steering angle, steering wheel neutral position detecting means b for detecting the neutral position of the steering wheel within a predetermined steering angle range, and at least When the neutral position is detected, and the steering angle is within a corrected steering angle range by a steering operation intended for straight running of the driver, a neutral steering angle estimated value calculating means c for estimating the neutral steering angle, A neutral steering angle estimated value storage means d for storing the neutral steering angle estimated value even when the power is turned off, and means for including the steering angle absolute value in the control information,
When the power is turned off and then turned on again, when the steering wheel neutral position is detected within the range where the steering angle detection value is less than ± 180 degrees, the control is started using the previously stored neutral steering angle estimation value. And a control means e.

(Operation) The control of the dynamic characteristic control means e is performed by turning the power off and then on again, and when the steering wheel neutral position is detected within the range where the steering angle detection value is less than ± 180 degrees Start with the corner estimate. Therefore, there is no delay in starting the control unlike when the neutral steering angle estimated value is newly calculated and the control is started when the power is turned on again.

In addition, erroneous detection of the neutral position of the steering wheel, such as when control is immediately started when the power is turned on again, is prevented.

Therefore, it is possible to achieve both early achievement of the control start timing and prevention of erroneous detection of the steering wheel neutral position while maintaining high control accuracy.

(Example) Hereinafter, the Example of this invention is described in detail based on drawing.

FIG. 2 is a diagram showing an overall configuration of a four-wheel steering vehicle equipped with a rear wheel steering control system (an example of a vehicle dynamic characteristic control device) of the embodiment.

 First, the configuration will be described.

In Fig. 2, 1L and 1R are left and right front wheels, 2L and 2R are left and right rear wheels,
3 is a handle. The front wheels 1L and 1R can be steered via the steering gear 4 by the steering wheel 3, respectively, and the rear wheels 2L and 2R can be steered.
Each R can be steered by the rear wheel steering actuator 5.

The rear wheel steering actuator 5 is a spring center type hydraulic actuator, and when supplying hydraulic pressure to the chamber 5R,
The rear wheels 2L and 2R are steered to the right by a steering angle proportional to the pressure,
When hydraulic pressure is supplied to the chamber 5L, only the steering angle proportional to the pressure is applied to the rear wheels
2L and 2R shall be steered to the left respectively.

An electromagnetic proportional rear wheel steering control valve 6 for controlling the hydraulic pressure to the actuator chambers 5L, 5R is provided, and this valve 6 has a structure in which variable throttles 6a, 6b, 6c, 6d are connected in a bridge, and a pump 7 is connected to this bridge circuit. , Reservoir 8 and actuator chamber
Connect oil paths 9 and 10 from 5L and 5R respectively.

The control valve 6 is further provided with solenoids 6L and 6R, and when the solenoids 6L and 6R are OFF, the variable throttles 6 are respectively provided.
When a, 6b and 6c, 6d are fully opened, both actuator chambers 5L, 5R are in a non-pressure state, and when the solenoid 6L or 6R is turned on by the dithered drive current I _L ^* or I _R ^* , the variable throttle 6c, 6d or 6a , 6b to the opening corresponding to the current value and the actuator chamber 5L or 5R
The hydraulic pressure should be supplied according to the current value of the dithered drive current I _L ^* or I _R ^* . As described above, this hydraulic pressure steers the rear wheels 2L, 2R in the corresponding direction by an angle corresponding to the value.

Oil passages 9 and 10 between the electromagnetic proportional type rear wheel steering control valve 6 and the rear wheel steering actuator 5 (the oil passages before and after the cut valve 20 are 9-1, 9-2 and 10-1, 10-, respectively). 2)
A cut valve 20 having a solenoid opening / closing valve structure is inserted midway. This cut valve 20 is a normally closed type and is used when the ignition is OFF or when it fails.
When the solenoid driving current I _F is not supplied to the oil passage 9
When the rear wheel steering control is normally performed by shutting off between 1,9-2 and 10-1,10-2, the solenoid drive current
When I _F is supplied, between oil passages 9-1, 9-2 and 10-
Connect between 1 and 10-2.

The fail time when the cut valve 20 is closed means that the microcomputer 6 has runaway, the sensor is abnormal, or the solenoids 6L and 6R of the control valve 6 are broken or short-circuited. Turn on 21.

Applying a dithered drive current I _L ^* or I _R ^* to the control valve solenoids 6L and 6R, and cutting valve solenoids
Apply solenoid drive current I _F to 20a, or alarm lamp 2
The rear wheel turning control unit 30 that applies the ON / OFF signal to 1 includes a steering wheel angle sensor 40 that detects a steering direction and a steering angle θ as sensors that provide input information, and a neutral position of the steering wheel. Steering wheel neutral position sensor 41 detected by the ON signal in the steering angle range
And a vehicle speed sensor 42 for detecting a vehicle speed V, an ignition switch 43 and the like.

And, in this rear wheel steering control unit 30,
As shown in the block circuit diagram of FIG. 3, as internal circuits, an A / D converter 30a, a neutral steering angle estimated value arithmetic circuit 30b, a backup memory 30c, a front wheel steering angle arithmetic circuit 30d, a rear wheel steering angle arithmetic circuit 30e. , D / A converter 30f, θ _R -I converter 30g,
It has a dither setting circuit 30h, a solenoid drive circuit 30i, an abnormality detection circuit 30j, a fail-safe circuit 30k, a solenoid drive circuit 30l, a display drive circuit 30m, and a self-diagnosis circuit 30n.

The steering wheel steering angle sensor 40 and the steering wheel neutral position sensor 41 are, as shown in FIG. 4, a disc-shaped sensor disk 51 fixed to a steering shaft 50 that rotates together with the steering wheel 3, and a steering wheel sensor 3 fixed to the vehicle body side. It is composed of a set of light emitting diodes and a photo IC.

One steering wheel angle sensor 40 has a sensor disc 51
Two sets of light emitting diodes and photo ICs (first sensor unit 40a and second IC) arranged at half pitch intervals corresponding to steering angle detection slits 51a opened at intervals of several degrees over the entire circumference of
The steering angle θ is detected by counting the number of pulses corresponding to the amount of turning of the steering wheel, and at the time of turning right and turning left as shown in FIG. 5 and FIG. At the time, the turning direction is detected based on the difference in the phase shift between the output pulse waveforms from the sensor units 40a and 40b.

The other handle neutral position sensor 41 is constituted by a set of light emitting diodes and a photo IC arranged corresponding to a neutral position detecting slit 51b which is opened in a range of about 20 ° on the circumference. As shown in FIG. 7, when the steering wheel is near the neutral position and the light emitting diode and the photo IC are on the neutral position detecting slit 51b, detection is made by outputting an ON signal.

It should be noted that the neutral position is detected within a range of about 20 ° because the error range due to the assembly accuracy in the factory is approximately ± 5.
The angle is 10 °, and the driver's range of correction steering is ±
By setting the angle to 5 °, which is 10 °, the range that can reliably output the ON signal when traveling straight ahead is set to 20 °, which is the sum of the two.

 Next, the operation will be described.

(A) Rear wheel turning control start processing operation FIG. 8 is a flowchart showing a flow of rear wheel turning control start processing operation from turning on the ignition switch 43 to starting rear wheel turning control.

First, the rear wheel steering control start processing operation starts when the ignition switch 43 is turned on.
In this case, the rear wheel turning control is prohibited until the final step is executed and a rear wheel turning control start command is output.

In step 81, the steering angle θ of the steering wheel at the time when the ignition switch 43 is turned on is set as θ ₀₀ .

In step 82, it is determined whether the stored neutral steering angle estimated value θ _CMO exists in the backup memory 30c.

Then, normally, the previously stored neutral steering angle estimated value θ _CMO at the time when the ignition switch 43 is turned ON → OFF during the previous travel etc. is present in the backup memory 30c, so the routine proceeds to step 83, where the previously stored neutral steering angle is stored. The estimated angle value θ _CMO is set as the stored neutral steering angle estimated value θ _CM .

Further, in the case of initialization of the rear wheel steering control unit 30, etc., if the previously stored neutral steering angle estimated value θ _CMO does not exist in the backup memory 30c, proceed to step 84 and step 85, and as shown in FIG. The neutral steering angle estimated value calculation shown is performed, and the setting of the stored neutral steering angle estimated value θ _CM is awaited. This is because even if the command to start the rear wheel steering control is output when the stored neutral steering angle estimated value θ _CM does not exist, the front wheel steering angle θ
_{This is because} the calculation processing of _F cannot be performed and the rear wheel turning control does not proceed.

In step 86, it is determined whether the neutral position signal CP from the steering wheel neutral position sensor 41 is an ON signal.

In step 87, the steering angle θ of the steering wheel at the time when the neutral position signal CP from the steering wheel neutral position sensor 41 becomes an ON signal is set as θ ₀₁ , and the neutral position signal CP from the time when the ignition switch 43 is turned on. The steering amount Δθ ₀ up to the point when the signal becomes an ON signal is calculated by the following equation.

Δθ ₀ = θ ₀₁ −θ _{00 At} step 88, it is determined whether the steering amount Δθ ₀ is within the range of ± 60 °.

When the steering amount Δθ ₀ exceeds the range of ± 60 °, the neutral position signal CP becomes the ON signal within the range of the steering amount Δθ ₀ which is the start condition of the rear wheel steering control within the range of ± 60 °. Until step 86 to step 88 are repeated.

If the steering amount Δθ ₀ is within the range of ± 60 °, the routine proceeds to step 89, where a rear wheel steering control start command is output.

Therefore, in the above-mentioned rear wheel steering control start processing operation, when the ignition switch 43 is switched from OFF to ON and the power of the rear wheel steering control unit 30 is turned on again, the steering amount Δ
When the neutral position signal CP becomes an ON signal within the range of θ ₀ within ± 60 °, the rear wheel steering control is started. Therefore, the neutral steering angle estimated value calculation circuit 30b newly calculates the neutral steering angle estimated value θ _C. There is no significant delay in the start of the rear wheel steering control as in the case of starting the rear wheel steering control after it has been operated, and in the normal case, the rear wheel steering control is turned on within a few seconds after the ignition switch 43 is turned on. Will be started.

Further, when the ignition switch 43 is OFF, the power steering is also off, so it is almost unlikely that the steering amount is ± 60 ° or more. Therefore, the steering amount Δθ ₀
If the neutral position signal CP becomes an ON signal within the range of ± 60 °, it can be considered that the normal position of the steering wheel is at the time when the ON signal is detected.
It is also possible to prevent the steering wheel neutral position sensor 41 from erroneously detecting the steering wheel neutral position at the position where the steering wheel is turned 360 degrees, as in the case where the rear wheel steering control is immediately started when 43 is turned on.

In theory, erroneous detection of the steering wheel neutral position is prevented even if the rear wheel steering control is started when the neutral position signal CP becomes an ON signal within a range of less than ± 180 °.

As described above, in the rear wheel steering control system including the front wheel steering angle θ _F , which is the absolute steering angle value, in the control information,
Control start while the storage neutral steering angle estimated value theta _CM maintaining wheel steering control accuracy after high by using the previously stored neutral steering angle estimated value theta _CMO at the time of the ignition switch 43 to the ON → OFF at the previous running It is possible to achieve both early timing and prevention of erroneous detection of the neutral position of the steering wheel.

(B) Rear-wheel steering control and fail-safe operation FIG. 9 shows a flow of rear-wheel steering control operation and fail-safe operation performed after the control start command is output in the rear-wheel steering control start processing operation of FIG. It is a flowchart.

In step 90, it is determined whether or not a fail command is being output, which is output when any abnormality is detected by the abnormality detection circuit 30j.When the fail command is not output, the rear wheel steering control operation after step 91 is performed. If the fail command is output, the fail safe operation from step 97 onward is performed.

* Rear wheel steering control operation In step 91, the steering wheel angle θ, the vehicle speed V, and the stored neutral steering angle estimated value θ _CM are read.

In step 92, the front wheel steering angle θ _F is calculated by the following formula based on the steering wheel steering angle θ and the stored neutral steering angle estimated value θ _CM .

θ _F = | θ = θ _CM | In step 93, the target rear wheel turning angle θ _R is calculated based on the vehicle speed V and the front wheel steering angle θ _F.

In step 94, the target rear wheel turning angle θ _R is converted into a drive current I _L or I _{R according} to a previously given θ _R −I characteristic table.

In step 95, the dither-equipped drive current I _L ^* or I _R ^* obtained by adding dither according to a predetermined amplitude and frequency to the drive current I _L or I _R obtained in step 94 is output to the control valve solenoid 6L or 6R. .

In step 96, the solenoid driving current I _F according to ON signal to the valve solenoid 20a opens the cut valve 20 is output.

* The fail-safe operation step 97, the solenoid drive current by OFF signal to close the cut valve 20 to the valve solenoid 20a I _F
Is output.

In step 98, a lighting signal (ON) is output to the alarm lamp 21.

At step 99, it is checked whether the elapsed time ΔT from the failsafe command has reached a predetermined time ΔT ₀ (for example, 150 msec). If ΔT ≧ ΔT ₀ , then at step 100 the dither of the solenoid 6L or 6R of the control valve 6 is checked. A command to turn off the drive current I _L ^* or I _R ^* is output.

Thus, in the rear wheel steering control operation, for example, as shown in FIG. 10, and turning control of the rear wheels in the opposite phase for a moment to the front-wheel steering angle theta _F, then turning control to the in-phase first-order-advance of When phase inversion control is performed, the rise of the yaw rate is improved by positively applying the generation of cornering force in the yaw generation direction, and after sufficient yawing is obtained, the rear wheels are turned to the same phase. By suppressing the increase in yaw rate by steering, it is possible to suppress the occurrence of a vehicle side slip angle, thereby increasing steering stability and obtaining high responsiveness.

 It is especially effective in the low and medium speed range.

In fail-safe operation, the oil pressure is cut by the cut valve 20 and then the oil leak from the cut valve 20 is used to gradually return the rear wheels to the neutral position. The sudden change in vehicle behavior is prevented.

(C) Neutral steering angle estimated value calculation start processing operation FIG. 11 is a flowchart showing the flow of the neutral steering angle estimated value calculation start processing operation from when the ignition switch 43 is turned ON to when the neutral steering angle estimated value calculation is started. is there.

First, the neutral steering angle estimated value calculation start processing operation starts from the time when the ignition switch 43 is turned on, and in step 110, the neutral steering angle estimated value calculation is prohibited until the start command of the neutral steering angle estimated value calculation is output. To be done.

Steps 111 to 116 are steering wheel neutral position sensor normality confirmation processing steps that are performed in advance when starting the calculation of the neutral steering angle estimated value.

In step 111, it is determined whether the neutral position signal CP from the steering wheel neutral position sensor 41 has changed from an OFF signal to an ON signal.

In step 112, when the neutral position signal CP changes from the OFF signal to the ON signal, the steering angle θ of the steering wheel at that time is θ.
Set as _MIN .

In step 113, it is determined whether the neutral position signal CP from the steering wheel neutral position sensor 41 has changed from an ON signal to an OFF signal.

In step 114, when the neutral position signal CP changes from the ON signal to the OFF signal, the steering angle θ of the steering wheel at that time is θ
Set as _MAX .

In step 115, the neutral position signal width θ _CP is calculated by the following equation from θ _MIN and θ _MAX .

θ _CP = θ _MAX −θ _{MIN In} step 116, whether the neutral position signal θ _CP matches the angular range of the neutral position detecting slit 51b opened in the sensor disk 51 within a range of about 20 ° is ± 5. If it is determined that the allowable angle of ° is 15 ° and θ _CP ≦ 25 °, the steering wheel neutral position sensor 41 is confirmed to be normal, and in step 117 a command to start the neutral steering angle estimated value calculation is output. To be done.

On the other hand, when θ _CP <15 ° or θ _CP > 25 °,
Based on the determination that the steering wheel neutral position sensor 41 is abnormal for some reason, a fail command is output in step 118, and the neutral steering angle estimation value calculation and the rear wheel turning control are not performed in steps 97 to 97 in FIG. 100 fail operations are performed.

Therefore, in the neutral steering angle estimated value calculation start processing operation, the neutral position signal width θ _CP is 15 ° ≦ 15 ° prior to the neutral steering angle estimated value calculation.
Since it is confirmed that the steering wheel neutral position sensor 41 is normal depending on whether or not θ _CP ≤25 °, the neutral steering angle estimated value calculation is started after it is confirmed that the steering wheel neutral position sensor 41 is normal. Even if the position sensor 41 is abnormal due to disconnection, short circuit, etc., the steering wheel neutral position is erroneously recognized as in the case where the neutral steering angle estimated value calculation is started without checking whether the steering wheel neutral position sensor 41 is normal. It is possible to avoid, and it is possible to calculate the accurate neutral steering angle estimated value θ _C.

(D) Neutral steering angle estimated value calculation processing operation FIG. 12 shows the flow of the neutral steering angle estimated value calculation processing operation performed after the calculation start command is output in the neutral steering angle estimated value calculation start processing operation of FIG. It is a flowchart shown.

In step 120, it is determined whether or not the neutral position signal CP is an ON signal. If the signal is an ON signal, the process proceeds to a neutral steering angle estimated value calculation process after step 121.

In step 121, it is determined whether or not the neutral steering angle estimated value calculation flag SFLG is equal to SFLG = 0, which indicates the time of the initial calculation condition.
Fly to 123.

In step 122, initial conditions V ₀ ,
θ ₀ and L ₀ are set.

Here, V ₀ is the speed condition, for example, is set as an initial vehicle speed condition 20 km / h.

θ ₀ is a corrected steering angle condition, for example, set to 10 ° as an initial corrected steering angle condition.

L ₀ is the continuous travel distance condition when the vehicle speed condition and the corrected steering angle condition are satisfied.
Is set to

In step 123, the vehicle speed V and the corrected steering angle theta _S and continuous running distance L is calculated by a separate flow.

In steps 124, 125 and 126, it is judged whether or not the respective conditions for the neutral steering angle estimated value calculation are simultaneously satisfied.

In step 124, the maximum vehicle speed condition V _MAX by the vehicle speed V is the vehicle speed conditions greater than or equal _to V ₀ (e.g., 80 km / h) whether the following is determined.

In step 125, it is determined whether the corrected steering angle θ _S is equal to or smaller than the corrected steering angle condition θ ₀ .

In step 126, the continuous traveling distance L is the continuous traveling distance L _0.
It is determined whether or not the above.

In this calculation condition determination, when the vehicle speed condition and the corrected steering angle condition are simultaneously satisfied, the maximum value θ _MAX and the minimum value θ _{MIN of the} steering wheel steering angle θ are set in step 127,
If any of the conditions is not satisfied, the maximum value θ _MAX and the minimum value θ _MIN set in step 128 are cleared.

Then, when satisfying all the operational conditions of the steps 124, 125, 126, the process proceeds to step 129, the maximum value theta _MAX and the minimum value theta obtaining an average value of the _MIN expression by the neutral steering angle estimated value theta _C below is calculated.

In step 130, the neutral steering angle estimated value θ _C is obtained in step 129.
Is determined, the average value of the present value θ _CN and the previous value θ _CN-1 is updated as the latest stored neutral steering angle estimated value θ _CM .

In step 131, when the neutral steering angle estimated value is updated, when the vehicle speed V, the corrected steering angle θ _S , and the continuous travel distance L calculated in step 123 at the time of updating are updated next, the neutral steering angle estimated value is updated. The neutral steering angle estimated value calculation condition is set as V ₀ , θ ₀ , L ₀ .

In step 132, the vehicle speed V, the corrected steering angle θ _S , the continuous running distance L are cleared, and the neutral steering angle estimated value calculation flag SF is cleared.
LG is set to SFLG = 1.

If the neutral position signal CP is an OFF signal in the determination at step 120, the process proceeds to neutral angle estimation value error detection processing after step 133.

In step 133, a steering angle error Δθ corresponding to the front wheel steering angle θ _F is calculated from the steering wheel steering angle θ and the stored neutral steering angle estimated value θ _CM by the following formula.

Δθ = | θ−θ _CM | In step 134, the steering angle error Δθ is the setting error Δθ ₂
(For example, 2 °) or more is determined, and when Δθ ≧ Δθ ₂ because the neutral position is not detected, it is determined that the error of the stored neutral steering angle estimated value θ _CM is small, and the process proceeds to step 135, where the neutral steering angle is determined. The estimated value calculation flag SFLG is set to SFLG = 1 indicating the update calculation condition. If Δθ <Δθ ₂ even though the neutral position is not detected, the stored neutral steering angle estimated value θ _CM is considered to be large in error and the process proceeds to step 136, where the neutral steering angle estimated value calculation flag SFLG is set. SFLG = 0 indicating the initial calculation condition is set.

Therefore, in this neutral steering angle estimated value calculation processing operation, the vehicle speed condition is included in the neutral steering angle estimated value calculation condition, and the vehicle speed V is reduced.
20 km / h 80 km (Initial speed condition V ₀₎ or / h (maximum speed conditions
V _MAX ), the neutral steering angle estimated value calculation is not performed at a low vehicle speed of less than 20 km / h or at a high vehicle speed of more than 80 km / h.

For this reason, when the vehicle is turning for a certain distance or for a certain period of time with the steering wheel being held at a position where the steering wheel is rotated once at a low vehicle speed when making a small radius turning, the steering wheel neutral position sensor 41 detects a position deviating from the regular position by about 360 °. False detection of the neutral position is prevented.

Further, when the vehicle travels in a large radius while maintaining steering with the steering wheel slightly turned at a high vehicle speed when the tire slip angle becomes large, the steering wheel neutral angle detected by the steering wheel neutral position sensor 41 is erroneously detected as the neutral position by the steering wheel neutral position sensor 41, It is prevented from setting the position that do not go straight state as neutral steering angle estimated value theta _C.

Also, when an error occurs in the stored neutral steering angle estimated value θ _CM , the neutral steering angle estimated value calculation condition is returned to the initial calculation condition that is less sweet than the update calculation condition, so that the steering wheel steering operation is performed by a high-speed steering wheel turning operation or the like. If skipping was neutral steering angle estimated value theta _C corner theta deviates significantly from a normal value, operation timing of the next neutral steering angle estimate is performed accelerated early in the normal storage the neutral steering angle estimated value theta You can return to _CM .

Although the embodiment has been described above with reference to the drawings, the specific configuration and control contents are not limited to this embodiment.

For example, in the embodiment, an example of a rear wheel steering control system is shown as a vehicle dynamic characteristic control device.However, an auxiliary steering control system or an active suspension control system that performs steering control of front and rear wheels by an actuator during front wheel steering,
Needless to say, it can be applied to any system that includes the absolute value of the steering angle in the control information.

(Effects of the Invention) As described above, in the vehicle dynamic characteristic control device of the present invention, when the power is turned off and then turned on again,
When the steering wheel neutral position is detected within the range where the steering angle detection value is less than ± 180 degrees, the dynamic steering control is started by using the previous stored neutral steering angle estimated value. In the vehicle dynamic characteristic control device including the above, there is an effect that it is possible to achieve both early achievement of the control start timing and prevention of error detection of the steering wheel neutral position while maintaining high control accuracy.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a complaint of a vehicle dynamic characteristic control device of the present invention, FIG. 2 is a diagram showing an overall configuration of a four-wheel steering vehicle equipped with a rear wheel steering control system, and FIG. 3 is a rear wheel steering control system. A block circuit diagram of the rear wheel steering control unit, FIG. 4 is a diagram showing a steering wheel steering angle sensor and a steering wheel neutral position sensor, and FIGS. 5 and 6 are a steering wheel steering angle sensor when turning right and turning left. FIG. 7 is a diagram showing a steering angle pulse signal, FIG. 7 is a diagram showing a neutral position signal output from a steering wheel neutral position sensor, FIG. 8 is a foot chart showing a flow of rear wheel steering control start processing operation, and FIG. Flowchart showing the flow of wheel steering control operation and fail-safe operation, FIG. 10 is a time chart showing an example of rear wheel steering control, and FIG. 11 is a flow chart showing the flow of neutral steering angle estimated value calculation start processing operation. FIG. 12 is a flowchart showing the flow of the neutral steering angle estimated value calculation processing operation. a: steering wheel steering angle detection means b: steering wheel neutral position detection means c: neutral steering angle estimated value calculation means d: neutral steering angle estimated value storage means e: dynamic characteristic control means

Claims (1)

(57) [Claims] 1. A steering wheel steering angle detecting means for detecting a steering wheel steering angle, a steering wheel neutral position detecting means for detecting a neutral position of the steering wheel within a predetermined steering angle range, and at least at the time of detecting the neutral position, and Neutral steering angle estimation calculation means for estimating the neutral steering angle when the steering angle is within the corrected steering angle range due to the steering operation intended for the straight running of the driver, and the neutral steering angle estimated value is stored even when the power is turned off. The neutral steering angle estimated value storage means and the means for including the absolute steering angle value in the control information.When the power is turned off and then turned on again, the steering angle detection value is within ± 180 degrees. A vehicle dynamic characteristic control device comprising: a dynamic characteristic control means for starting control using a previous stored neutral neutral steering angle estimated value when a steering wheel neutral position is detected.