JPH01270635A - Apparatus for controlling torque of drive wheel of vehicle - Google Patents

Abstract

PURPOSE:To realize desired yaw movement while suppressing the lowering of effective driving force with due regard to the states of revolving movement and slip, by calculating the correction value of a drive slip reference value on the basis of the state of the revolving movement and the reference value thereof. CONSTITUTION:A yaw rate detection means 10 consists of a subtractor circuit 14, a multiplier circuit 15 and histeresis accumulation circuits 17, 18 respectively accumulating the output histeresis of a filter 16 to detect the revolving movement state of a vehicle. A reference yaw rate setting means 11 consists of a constant selecting circuit 19 and histeresis accumulation circuits 20, 22 to generate the reference value of the revolving movement state of the vehicle. A correction value setting means 5 consists of a correction value operation circuit 24 and a multiplier circuit 25 to calculate the correction value of a drive slip reference value on the basis of the revolving movement state and the reference value of revolving movement. By this method, the drive slip reference value is corrected on the basis of the correction value set based on the revolving state and the reference value thereof and a slip state is detected on the basis of the slip reference value after correction and the torque of a drive wheel is controlled while the steering quantity of the vehicle is considered and the lowering of effective driving force is suppressed.

Description

Detailed Description of the Invention A9 Object of the Invention (1) Industrial Application Field The present invention relates to a drive slip reference value setting method for setting a drive slip reference value for detecting the slip state of the drive wheels of a vehicle in the drive direction. The present invention relates to a drive wheel torque control device for a vehicle, including a control amount setting means for setting a drive torque reduction control amount for reducing drive wheel torque in accordance with a slip state of the drive wheels.

(2) Prior Art Conventionally, such a device has been known, for example, from Japanese Patent Publication No. 1988-198.

(3) Problems to be Solved by the Invention By the way, the above conventional system detects the slip state of the driving wheels and reduces the driving torque of the driving wheels in order to obtain the maximum driving force. The limit lateral force generated at the drive wheels becomes larger when the driving force is reduced rather than when the maximum driving force is obtained. Therefore, if the vehicle is steered when a slip condition is detected and the drive wheel torque is reduced as described above, the yaw movement requested by the driver will not be achieved if the steering is within the limit lateral force. However, if the steering exceeds the limit lateral force, the yaw movement requested by the driver will not occur, and front engine/front drive (FF) vehicles will tend to understeer, and front engine/rear Drive (FR) 2 vehicles tend to oversteer.

The present invention has been made in view of the above circumstances, and provides a drive wheel torque for a vehicle that takes into account the turning motion state and the slip state, and makes it possible to realize a desired yaw motion while suppressing a decrease in effective driving force. The purpose is to provide a control device.

B. Structure of the Invention (1) Means for Solving the Problems The device of the present invention includes a turning movement state detection means for detecting the turning movement state of a vehicle, and a turning movement base $ value for generating a reference value for the turning movement state of the vehicle. and a correction value setting means for determining a correction value of the driving slip reference value based on the turning movement state and the reference value of the turning movement.

(2) Effect According to the above configuration, the driving slip reference value is corrected by the correction value set based on the turning movement state and the reference value of the turning movement state, and the slip state is corrected by the corrected driving slip reference 4L value. Since this is detected, the driving wheel torque can be controlled while taking into account the amount of steering of the vehicle, and a desired turning motion can be obtained while suppressing a decrease in the effective driving force.

(3) Embodiment Below, an embodiment of the present invention will be explained with reference to the drawings. First, in FIG. That is, the left and right front wheels Wfff, Wf
Drive slip reference value setting means 1 for setting first and second reference wheel speeds Vrl, Vrz as reference values for detecting a slip state in the drive direction of r, and those reference wheel speeds Vr, , Vr, . a control amount setting means 2 for setting the drive wheel I/lux reduction control amount A according to the slip condition when a slip condition is detected based on the yaw rate as a turning motion state detection means for detecting the turning motion state of the vehicle. a detection means 10; a reference yaw rate setting means 11 as a turning motion reference value generating means for generating a reference value for the turning motion state; The driving torque of both front wheels Wfff and Wfr is reduced in response to the control iA from the control amount setting means 2 and the correction value setting means 5 which calculates the correction value B-K for correcting the second reference wheel speeds Vr, Vr2. The drive wheel I-lux reduction means 7 is provided to reduce the I-lux of the drive wheels.

Speed sensors 5rj2°Srr are individually attached to the free rolling wheels of the vehicle, that is, the left and right rear wheels Wrff, Wrr in an FF vehicle, and these speed sensors Srβ, Sr
The wheel speed detected at r is input to the vehicle speed detector 8 and also to the yaw rate detection means 10. The vehicle speed detector 8 obtains the vehicle speed Vv by averaging the speeds of both free rolling wheels, and this vehicle speed Vv is determined by the selection circuit 9, the drive slip reference value setting means 1, the reference yaw rate setting means 11 and the allowable The values are respectively input to the deviation value setting means 4.

The left and right front wheels Wfff and Wfr, which are the driving wheels, are equipped with a speed sensor.
The wheel speeds detected by these speed sensors Sff and Sfr are input to the selection circuit 9, and one of the driving wheel speeds on both sides is selected depending on the vehicle speed Vv. It is selected as the speed Vw. That is, when the vehicle speed Vv is extremely low, for example less than 4 km/h, the lower of the driving wheel speeds on both sides is selected as the driving wheel speed Vw, and when the vehicle speed V'v is 4 km/h or more, both side driving wheel speeds are selected as the driving wheel speed Vw. The higher side driving wheel speed is selected as the driving wheel speed Vw. This driving wheel speed Vw is input to the control amount setting means 2.

Further, a steering angle sensor Ss is attached to the steering handle H, and the steering angle δ detected by the steering angle sensor Ss is inputted to the reference yaw rate setting means 11 and the allowable deviation value setting means 4.

As shown in FIG. 2, the drive slip reference value setting means 1 sets a first reference wheel speed Vr and a second reference wheel speed ■r2 as drive slip reference values in accordance with the vehicle speed Vv. The first speed corresponding to the input vehicle speed Vv
and second reference wheel speed Vr1. Vrz is output from the drive slip reference value setting means 1. First reference wheel speed V
r is determined according to the allowable slip ratio, and the second reference wheel speed ■r2 is set to be larger than the first reference wheel speed Vr+, assuming that excessive slip is occurring.

The first and second reference wheel speeds Vr+ and Vrz obtained by the drive slip reference value setting means 1 are input to the correction means 6, and the correction means 6 corrects the correction value B- input from the correction value setting means 5. The first and second reference wheel speeds Vr+ and Vrz are respectively modified by K as follows.

V r, -V r, -B- = 11) V r z = V r 2 B-K - (2) The first and second reference wheel speeds Vrl after being corrected by the correction means 6 in this way, Vrz and the drive wheel speed Vw obtained by the selection circuit 9 are input to the control amount setting means 2. In the control amount setting means 2, the driving wheel torque reduction control amount corresponding to the slip state is determined based on the first and second reference wheel speeds r, , Vrz, as shown in the following equation.

■r2-■rI The larger the value of this control amount A, the larger the amount of torque reduction.If (VwVr+) is negative, that is, the driving wheel speed Vw is lower than the first reference wheel speed Vr. In the case of speed, A=0.

The yaw rate detection means 10 includes a subtraction circuit 14, a multiplication circuit 15, a filter 16, a history accumulation circuit 17 that accumulates the output history of the multiplication circuit 15, and a history accumulation circuit 18 that accumulates the output history of the filter 16. . The free rolling wheel speeds obtained by the speed sensors 5rff and Srr are input to the subtraction circuit 14, and the difference r between the free rolling wheel speeds is obtained by the subtraction circuit 14. The multiplication circuit 15 multiplies the difference r by a constant proportionality constant d to obtain an approximate value y' (-r x d ) of the yaw rate. Here, the proportionality constant d is the tread width of the left and right rear wheels Wrn, Wrr, and is, for example, d=1.

The filter 16 eliminates the influence of vibrations of the vehicle suspension on the wheel speed, and is a recursive filter. Here, the fluctuation in wheel speed due to resonance with suspension vibration while driving on rough roads is about 10Hz,
The frequency range of the yaw rate used to control vehicle motion is 0 to
Since the frequency is 20 Hz, the filter 16 filters the value y' near the yaw rate with an attenuation range of 2112 or higher.

That is, in the fill 16, the following equation (4) is performed, where the output value is y'.

y, = αl'3'+1-Tomi+αz'Vn-2+α3・y
n-:t+βsummer'Vn'+β2・yn-+'10β,・y,,-3'...(4)
Here, α1...α3. β1...β3 are constants determined by experimental results. Also a subscript.・・・・・・7
-3 represents the current value, previous value, etc. of the cycle because the filtering calculation is repeated in a constant cycle, and the previous value, the value before the previous time, etc. of the approximate value y' of the yaw rate.
... is input from the history accumulation circuit 17 to the filter 16,
The previous value of yaw rate y, the value before the previous time, etc. are manually inputted from the history accumulation circuit 18 to the filter 16.

The reference yaw rate setting means 11 includes a constant selection circuit 19;
History accumulation circuit 20, arithmetic circuit 21, and history accumulation circuit 2
2. The constant selection circuit 19 selects constants a1 . a2, bl, and β2 are selected according to the vehicle speed Vv obtained by the vehicle speed detector 8, and the constants a+, which are determined as shown in FIG. β2. The values of bl and bz are input to the arithmetic circuit 21. Also, history accumulation circuit 2
0 is for manually inputting the history of the steering angle δ detected by the steering angle sensor Ss to the calculation circuit 21, and the history accumulation circuit 22
For example, the output value of the arithmetic circuit 21, that is, the reference yaw ray 1-y
The history of b is input to the arithmetic circuit 21. The arithmetic circuit 21 receives the history of the steering angle δ from the history accumulation circuit 20,
The current desired group yaw rate Yb is calculated based on the history of reference yawlays 1 to yh from the history storage circuit 22, and calculations according to the following (5) 2 are performed.

yb=aI0ybn-+a2°ybn-2 juice-b 1
・δ. −1+ b 2 δ , l−2...(
5) Yaw rate I・y obtained by the yaw rate detection means 10
and the reference yaw rate (yb) obtained by the reference yaw rate setting means 11 are input to the deviation value calculation circuit 12, and the deviation value calculation circuit 12 calculates the deviation Dr(- y−y, ) is calculated.

The deviation Dr is input to the steering characteristic determination circuit 13.

The steering characteristic determination circuit 13 includes the deviation Dr,
Reference yaw rate y from reference yaw rate setting means 11,
are input, and the steering characteristic discriminating circuit 13 uses these human forces Dr, y, and so on.

Steering characteristics are determined based on. In other words, the steering characteristic discriminating circuit 13 has predetermined criteria as shown in Table (1) below, and the results determined according to the criteria are determined by the steering characteristic discriminating circuit 1.
Output from 3.

Table (1) In Table (1), the symbol 1j Q indicates an oversteer link, and the symbol U indicates an understeering link.

The allowable deviation value setting means 4 receives signals indicating the vehicle speed Vv from the vehicle speed detector 8, the steering angle δ from the steering angle sensor Ss, and the determination result from the steering time discrimination circuit 13, respectively. has been input, and the allowable deviation value setting means 4
outputs reference values yn and yc based on these input signals. That is, the allowable deviation value setting means 4 sets the reference value yv based on the vehicle speed Vv and the determination result of the steering link characteristic determination circuit 13 when the steering angle δ is relatively small.
, yc are set as shown in Fig. 4, and the steering angle δ
When the reference value y becomes relatively large, the reference values yn and Vc are set thicker than the values shown in FIG. The standard value y
D is set in response to when the deviation between the vehicle-specific steering characteristics and the actual steering characteristics has progressed to an unacceptable state.

The deviation Dr output from the deviation value calculation circuit 12 is converted into an absolute value by the absolute value conversion circuit 23 and then inputted to the correction value setting means 5, and the reference value yゎ from the allowable deviation value setting means 4 is
Vc is input to the correction value setting means 5.

The correction value setting means 5 includes a correction value calculation circuit 24 and a multiplication circuit 25, and is configured to calculate the absolute value of the deviation Dr and the reference value 3.
'D and yC are input to the correction value calculation circuit 24. This correction value calculation circuit 24 performs calculations according to the following equation.

1Drlyc B-□...(6) Vo Vc Note that when (lDrlyc) is negative, the above B is set to 0.

The value B obtained by this calculation is input to the next multiplier circuit 25, and the multiplier circuit 25 multiplies the above B by a constant K to obtain a modified value B.
-K is obtained, and this correction value B-K is input to the correction means 6. Note that the first and second reference wheel speeds Vr1 + ■r2 corrected by the correction value B-K are the vehicle speed Vv
If it becomes lower, it becomes equal to the vehicle speed Vv.

Drive wheel torque control amount A output from control amount setting means 2
is input to the drive shaft torque reduction means 7, and the drive wheel torque reduction means 7 reduces the drive shaft torque according to the input control amount A. As this drive shaft torque reduction means 7,
Devices that reduce the amount of fuel supplied to the engine, devices that lower the throttle opening, devices that reduce the transmission rate of braking devices and continuously variable transmissions, and devices that delay the engine's ignition timing or cut the ignition are used. .

Next, to explain the operation of this embodiment, in a front engine/front drive vehicle, the driving force and limit lateral force of the front wheels are as shown in Fig. 5. As the driving force increases, the limit lateral force decreases, and the As the force decreases, the critical lateral force increases. According to the present invention, the reference values for determining the slip state of the drive wheels, that is, the first and second reference wheel speeds Vr1 + ■r2, are corrected according to the turning motion state of the vehicle, and the corrected First and second reference wheel speeds Vr
A drive wheel torque reduction control amount A is determined based on 1+Vr2, and the drive wheel torque reduction means 7 is activated by the drive wheel torque reduction control amount A to reduce drive shaft torque. Therefore, by lowering the reference value for determining a slip state in response to the turning motion state corresponding to the steering of the vehicle, it is possible to reduce the driving force and increase the critical lateral force.
It becomes possible to perform a turning movement corresponding to the amount of steering by the driver within the range of the limit lateral force.

In addition, even in rear-drive vehicles, the relationship between driving force and critical lateral force exists for the rear wheels, which are the driving wheels, and the lateral force required of the rear wheels exceeds the critical lateral force relative to the driving force acting on the rear wheels. If the required lateral force is estimated to exceed the limit lateral force, it is effective to increase the limit lateral force by reducing the driving force of the rear wheels. . Therefore, the control of driving force and lateral force by the device of the present invention is effective even in rear-drive vehicles.

As a result, it becomes possible to achieve the yaw motion desired by the driver while reducing the drive torque in accordance with the slip state of the drive wheels and suppressing a decrease in the effective drive force.

Further, as another embodiment of the present invention, the slip state of the driving wheels can be determined by determining whether at least one of the slip ratio and the differential value of the slip ratio exceeds a predetermined value, or whether the difference between the speeds of both driving wheels exceeds a predetermined value. Detection may also be made based on whether the Further, the reference yawlay (yb) may be a fixed value, in which case the steering characteristics are set based on the yawlay I and the deviation Dr. Furthermore, the lateral acceleration of the vehicle may be used to detect the turning motion state.

C1 Effects of the Invention As described above, the device of the present invention includes a turning movement state detection means for detecting the turning movement state of the vehicle, a turning movement reference value generating means for generating a reference value for the turning movement state of the vehicle, and a turning movement state detection means for detecting the turning movement state of the vehicle. and correction value setting means for determining a correction value of the driving slip reference value based on the reference values of the motion state and turning movement, so that the steering amount is determined by controlling the driving wheel torque in consideration of the steering of the vehicle. By adjusting the limit lateral force accordingly, it is possible to obtain the desired turning motion while suppressing a decrease in the effective driving force.

[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 graph showing an example of the output characteristics of the drive threshold value setting means, and FIG. FIG. 4 is a graph showing an example of the output characteristics of the constant selection circuit, and FIG.
M is a time indicating the relationship between the driving force and the limit lateral force. 1... Drive slip base [1 is value setting means, 2... Controlled amount setting means, 5... Correction value setting means, 10... Yaw rate detection means as turning movement state detection means, 11.
...Reference core rate setting means as turning motion reference value generation means, A...Drive wheel torque reduction control amount, Wfp, , Wfr.
・Front wheel as a driving wheel

Claims (1)

[Claims] Drive slip reference value setting means for setting a drive slip reference value for detecting the slip state of the drive wheels of the vehicle in the drive direction; and drive torque reduction control for reducing the drive wheel torque according to the slip state of the drive wheels. A driving wheel torque control device for a vehicle comprising a control amount setting means for setting a turning motion state, a turning motion state detection means for detecting a turning motion state of the vehicle, and a turning motion reference value for generating a reference value for the turning motion state of the vehicle. A drive wheel torque control device for a vehicle, comprising: a generating means; and a correction value setting means for determining a correction value of the drive slip reference value based on the turning motion state and the reference value of the turning motion.