JP2557232B2 - Vehicle turning motion control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention relates to a turning motion control device for a vehicle.

(2) Related Art Conventionally, an anti-lock brake is known as a device for controlling the turning motion of a vehicle.

(3) Problems to be Solved by the Invention However, the anti-lock brake focuses on the braking performance of the anti-lock brake, and in terms of exercise performance, the anti-lock brake only prevents the tire lateral force from decreasing.

Therefore, the present applicant detects the yaw rate as the turning momentum by the speed difference of the free rolling wheels of the vehicle, and the reference yaw rate as the reference turning momentum determined by the detected vehicle speed, yaw rate and history of the turning angle, A turning motion control device has already been proposed so that the engine output is reduced when the deviation from the detected yaw rate is larger than an allowable value.

However, in the above turning motion control device, when the allowable value is constant, control may be insufficient due to the inertial force of the turning motion of the vehicle when the turning angle is large. At this time, the reference yaw rate may be set so as not to cause the control shortage when the turning angle is large, but the reference yaw rate is not set only based on the output of the turning angle sensor, but the vehicle speed. It is difficult to determine the reference yaw rate so as not to cause insufficient control even if the allowable value is fixed, because it is determined by including other factors such as.

The present invention has been made in view of such circumstances,
An object of the present invention is to provide a turning motion control device for a vehicle in which control responsiveness is easily improved by changing an allowable value according to a turning angle.

B. Configuration of the Invention (1) Means for Solving Problems The device of the present invention is a turning momentum detecting means for detecting a turning momentum generated when the vehicle turns, a vehicle speed detector for detecting a vehicle speed, and a steering wheel. And a reference turning momentum generating means for outputting a reference turning momentum based on outputs of at least the vehicle speed detector and the turning angle sensor; reference turning momentum generating means and turning momentum detection Reference value generating means for determining a reference value of the output deviation of the means in accordance with the output of the steering angle sensor; reference value determined by the reference value generating means for the output deviation of the reference turning momentum generating means and the turning momentum detecting means Turning correction means for controlling the turning movement of the vehicle when larger than;
Is provided.

(2) Operation According to the above configuration, it is possible to detect that the turning momentum has an undesired value because the deviation between the detected turning momentum and the desired turning momentum based on the turning angle exceeds the reference value. Therefore, it is possible to control the turning motion, and since the reference value of the output deviation changes according to the turning angle, it is possible to perform appropriate turning motion control according to the turning angle.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, in FIG. 1 showing an embodiment of the present invention, speed sensors 11 and 1r are individually provided to left and right free rolling wheels Wl and Wr of a vehicle. The wheel speeds Vl and Vr detected by these speed sensors 1l and 1r are input to the yaw rate detecting means 2 and the vehicle speed detector 3 as turning momentum detecting means, respectively. A steering angle sensor 4 is attached to the steering handle H, and the steering angle δ detected by the steering angle sensor 4, the vehicle speed Vv obtained by the vehicle speed detector 3, and the yaw rate detecting means 2 The history of the yaw rate y as the turning momentum obtained in (4) is input to the reference yaw rate generating means 5 as the reference turning momentum generating means. And the yaw rate y obtained in the yaw rate detecting means 2, the reference yaw rate y _b as reference swing momentum generated from the reference yaw rate generating means 5, are input to the yaw correction means 6 as swirling motion correction means. Further, in the yaw motion correction means 6, the deviation Dr (= y between the yaw rate y and the reference yaw rate y _b
-Y _b ) is obtained, and the deviation Dr and the reference yaw rate y _b are input to the steering characteristic determination means 7. The determination result of the steering characteristic determination means 7, the vehicle speed Vv from the vehicle speed detector 3, and the turning angle δ from the turning angle sensor 4 are input to the reference value generating means 8. The vehicle is also provided with a switch 9 for switching the output voltage level between a high level and a low level depending on whether the drive wheel is the front wheel or the rear wheel. The output of the switch 9 is the drive wheel. The determination result is input to the determination circuit 10, and the determination result of the drive wheel determination circuit 10 is input to the reference value generating means 8. The reference value generation means 8 inputs a reference value signal that changes according to each input signal to the yaw motion correction means 6 to change the control mode of the yaw motion correction means 6.

The yaw rate detecting means 2 includes a subtraction circuit 11 and a multiplication circuit 12
A filter 13, a history storage circuit 14 that stores the output history of the multiplication circuit 12, and a history storage circuit 15 that stores the output history of the filter 13. The subtraction circuit 11 includes speed sensors 1l and 1
The difference r (= Vr-Vl) between the wheel velocities Vl and Vr detected by r is obtained. The multiplication circuit 12 multiplies the difference r by a constant proportional constant d to approximate the yaw rate y '(= r Xd) is obtained. Here, the proportionality constant d is the tread width of the free rolling wheels Wl, Wr, for example d = 1. Filter 13
The effect of vibration of the vehicle suspension on the wheel speeds Vl and Vr is eliminated, and a recursive filter is used. Here, the fluctuation of the wheel speeds Vl, Vr due to resonance with the vibration of the suspension during traveling on a rough road is about 10 Hz, and the frequency range of the yaw rate used for controlling the vehicle motion is 0 to 2 Hz. Using the above as the attenuation region, the approximate value y'of the yaw rate is filtered. That first follows the filter 13 and the output value is taken as y _n (1) computation of the expression is performed.

y _n = α ₁ · y _n-1 + α ₂ · y _n-2 + α ₃ · y _n-3 + β ₁ · y _n ′ + β ₂ · y _n-1 ′ + β ₃ · y _n-3 ′ (1 ) Here, α ₁ ... α ₃ , β ₁ ... β ₃ are constants determined by experimental results. The subscripts _n ... _n-3 represent the present value, several times, etc. of the cycle because the filtering operation is repeated in a constant cycle. Is input to the filter 13 from the history storage circuit 14, and the previous value, the last-previous value, etc. of the yaw rate y are input to the filter 13 from the history storage circuit 15.

The vehicle speed detector 3 outputs the vehicle speed Vv based on the wheel speeds Vl, Vr detected by the both speed sensors 1l, 1r. For example, the larger value of the both wheel speeds Vl, Vr is the vehicle speed. It is output as Vv.

The reference yaw rate generation means 5 includes a constant selection circuit 16, a history storage circuit 17, and an arithmetic circuit 18. Constant selection circuit
16 is a constant a ₁ , a ₂ , b ₁ , b used in the arithmetic operation in the arithmetic circuit 18.
₂ is selected according to the vehicle speed Vv obtained by the vehicle speed detector 3, and the constants a ₁ , a ₂ , b determined according to each vehicle, for example, as shown in FIG. The values of ₁ and b ₂ are input to the arithmetic circuit 18. The history storage circuit 17 inputs the history of the turning angle δ detected by the turning angle sensor 4 to the arithmetic circuit 18. The arithmetic circuit 18 uses the vehicle speed Vv obtained by the vehicle speed detector 3, the history of the yaw rate y from the history storage circuit 15 in the yaw rate detection means 2, and the history of the turning angle δ from the history storage circuit 17. based on provided for calculating the reference yaw rate y _b should be present, it follows the (2)
The operation according to the formula is performed.

y _b = -a ₁ · y _n-1 −α ₂ · y _n-2 + b ₁ · δ _n-1 + b ₂ · δ _n-3 ...
(2) The yaw motion correction means 6 calculates the deviation Dr (= y−y _b ) between the yaw rate y obtained by the yaw rate detection means 2 and the reference yaw rate y _b obtained by the reference yaw rate generation means 5. Circuit 19 and absolute value conversion circuit that converts deviation Dr to absolute value
20, the first and second comparators 21 and 22 to which the outputs of the absolute value circuit 20 are input to the inverting terminals, respectively, and the drive wheel output torque control circuit 23 to which the output ends of both comparators 21 and 22 are connected. It consists of and. The drive wheel output torque control circuit 23 controls, for example, the fuel supplied to the engine, and the first comparator 21
When the output is low level, the fuel supply amount is reduced to reduce the mixture concentration, and when the output of the second comparator 22 is low level, the fuel supply is shut off.

The reference yaw rate y _b from the reference yaw rate generating means 5 and the deviation Dr from the deviation calculating circuit 19 are input to the steering characteristic determining means 7, and the steering characteristic determining means 7 is supplied.
Have their inputs Dr, determines the steering characteristic based on y _b. That is, the steering characteristic determining means 7 has predetermined criteria as shown in the following Table (1).

In Table (1), the symbol O indicates over-steering and the symbol U indicates under-steering, and the result determined based on Table (1) is output from the steering characteristic determining means 7. .

In the reference value generating means 8, the vehicle speed Vv from the vehicle speed detector 3, the turning angle δ from the turning angle sensor 4, the determination result from the drive wheel determination circuit 10, and the determination result from the steering characteristic determination means 7. , Respectively, and the reference value generating means 8 outputs the output terminal C connected to the non-inverting terminal of the first comparator 21 based on the input signals.
And an output terminal D connected to the non-inverting terminal of the second comparator 22.
Output signals from and respectively. That is, the reference value generating means 8 outputs the output value of the output terminal C based on the vehicle speed Vv and the determination result of the steering characteristic determining means 7 when the vehicle is a front-wheel drive vehicle and the turning angle δ is relatively small. Is set as shown by the solid line in FIG. 3, and the output value of the output terminal D is set as shown by the broken line in FIG. When the vehicle is a rear-wheel drive vehicle, output values different from those in FIG. 3 are set. When the steering angle δ becomes relatively large, the output values of the output terminals C and D are as shown in FIG. The values are set to be smaller than the values.

Next, the operation of this embodiment will be described. The yaw rate y of the vehicle is determined by the speed difference (Vr−Vr) between the left and right free rolling wheels Wl and Wr.
It is obtained by multiplying l) by a proportional constant d and then filtering with the filter 13. The yaw rate y, which is practically no problem, can be easily obtained by eliminating the influence of the vehicle suspension.

And the yaw rate y which thus estimated vehicle speed Vv, the absolute value of the deviation Dr between the reference yaw rate y _b calculated as currently to a value based on a history of the turning angle δ and the yaw rate y is the reference value generating means When the reference value from the output terminals C and D of No. 8 is exceeded, the drive wheel output torque control circuit 23 is operated, and the yaw motion is controlled by detecting in advance that the vehicle will turn in an undesirable direction. You can

For example, in a front-wheel drive vehicle, when an excessive driving force is applied while turning the steering, an understeering tendency occurs, and when it is detected that the vehicle has turned in an undesired direction, the first and second comparators 21, The drive wheel torque control circuit 23 operates to reduce the engine output in accordance with the output of the engine 22. The driving force of the driving wheel decreases in accordance with the decrease in the engine output, and the limit lateral force of the driving wheel increases instead. Therefore, the above-described understeering can be prevented. On the other hand, in the case of a rear-wheel drive vehicle, over-steering tends to occur when an excessive drive force is applied, but in this case as well, in the same manner as in the case of a front-wheel drive vehicle, it is possible to prevent over-steering by reducing the drive force. You can By reducing the engine output in this manner, the actual yaw rate y
There approaches the reference yaw rate y _b, the output reduction of the engine is canceled and returns to normal engine output control.

Moreover, in the reference value generating means 8, the output values from the output terminals C and D are set differently depending on the determination result of the steering characteristic determining means 7, and, for example, when an oversteering tendency occurs in a front-wheel drive vehicle. As shown in FIG. 3, the output value from the output terminal D is set to be smaller during over-steering than under-steering, so that the vehicle is stable before it is over-steered. It becomes possible to set the speed, and in each of the over-steering and the under-steering, the output of the first comparator 21 becomes low level before the output of the second comparator 22 becomes low level, and the drive wheel output torque control is performed. The circuit 23 works to reduce the concentration of the air-fuel mixture in the engine, and the driving force gradually decreases. Therefore, it is possible to prevent the overcontrol state from being caused by a gradual decrease in the driving force.

Further, when the steering angle δ is large at low vehicle speed, the steering characteristic of the vehicle becomes non-linear, whereas the reference yaw rate y _b generated by the reference yaw rate generating means 5 is linear, so the reference yaw rate y _b Although the deviation Dr between the yaw rate y and the yaw rate y becomes large, the value from the reference value generating means 8 input to the first and second comparators 21 and 22 indicates that the vehicle speed Vv is large as shown in FIG. Since it is set to be smaller as it becomes, it is possible to prevent excessive control at low vehicle speed and prevent insufficient control at high vehicle speed.

Further, the output value from the reference value generating means 8 is set so as to decrease as the turning angle δ increases, so that the first comparator 21 or the second comparator when the turning angle δ is large.
The output of the motor 22 is likely to be at a low level, thereby preventing a shortage of control due to an increase in the inertia force of the yaw motion at a large steering angle when the steering handle H is turned greatly.

Further, since the output value from the reference value generating means 8 changes depending on which of the front wheel and the rear wheel is the drive wheel, the steering characteristic changes depending on whether the vehicle is a front wheel drive vehicle or a rear wheel drive vehicle. Appropriate yaw motion control becomes possible.

Moreover, the drive wheel output torque control circuit 23 switches between a control mode for reducing the mixture concentration to the engine and a control mode for shutting off the fuel supply to the engine according to the output from the reference value generating means 8. Compared with the control that only interrupts the fuel supply, more precise control can be performed, discomfort caused by a large torque difference can be eliminated, and excessive control can be prevented.

FIG. 4 shows another embodiment of the present invention.
Portions corresponding to the embodiment in the figure are denoted by the same reference numerals.

The 'calculation circuit 18 in the' reference yaw rate generating means 5, next (3) operation is performed in accordance with equation reference yaw rate y _b is obtained.

y _b = −a ₁・ y _bn-1 −a ₂・ y _bn-2 + b ₁・ δ _n-1 + b ₂・ δ _n-2 ...
(3) That is, the reference yaw rate y _b obtained by the arithmetic circuit 18 ′
History has been accumulated in the history storage circuit 25, histories y _bn-1 of the reference yaw rate y _b inputted from the history storage circuit 25,
y _bn-2 and the history δ _n-1 of the turning angle δ from the history storage circuit 17,
The reference yaw rate y _b is calculated from δ _n-2 .

Also, the drive wheel distribution control circuit 24
Is input. The driving force distribution control circuit 24 controls the driving force distribution ratio between the front wheels and the rear wheels of the vehicle. The driving force distribution ratio is detected by the driving wheel discriminating circuit 10 ′ and input to the reference value generating means 8. You.

According to this embodiment, in addition to the same effects as the foregoing embodiments, the reference yaw rate generating means 5 ', so to calculate a reference yaw rate y _b on the basis of the history of the reference yaw rate y _b, calculation formula Is simple, the cost can be reduced, and the deterioration of controllability caused by the complicated arithmetic expression can be avoided.

As still another embodiment of the present invention, the vehicle speed detector 3
May output the average value of the wheel speeds Vl, Vr of the two free rolling wheels Wl, Wr as the vehicle speed Vv.

Further, in the above-described embodiment, the deviation Dr of the reference yaw rate y _b and the actual yaw rate y is compared with the reference value.
The engine output (for example, throttle opening) may be controlled in proportion to the difference between the deviation Dr and the reference value. Furthermore, the reference yaw rate y _b was calculated by the history ( _n-1 , _n-2 ) up to the previous time and the time before last, but it is calculated by the history ( _n-1 , _n-2 , _n-3 , ...) that is higher than that. You may do it.

C. Effect of the Invention As described above, the device of the present invention detects a turning momentum that occurs when the vehicle turns, a vehicle speed detector that detects a vehicle speed, and a steering angle of a steering wheel. A turning angle sensor; a reference turning momentum generating means for outputting a reference turning momentum based on outputs of at least a vehicle speed detector and a turning angle sensor; a reference value of an output deviation of the reference turning momentum generating means and the turning momentum detecting means A reference value generating means for determining according to the output of the steered angle sensor; and when the output deviation of the reference turning momentum generating means and the turning momentum detecting means is larger than the reference value determined by the reference value generating means, Since the turning motion correction means for controlling the turning motion is provided, it is possible to control the turning motion by detecting that the vehicle turns in an undesired direction. Moreover, since changing the control characteristics by changing the reference value depending on the steering angle, the appropriate control is easily possible according to the turning angle.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention,
1 is an overall block diagram, FIG. 2 is a graph showing an example of output characteristics of a constant selection circuit, FIG. 3 is a graph showing an example of output characteristics of a reference value generating means, and FIG. 4 is another example of the present invention. It is a whole block diagram of an Example. 2 ... yaw rate detecting means as turning momentum detecting means, 3 ... vehicle speed detector, 4 ... steering angle sensor, 5,
5 '... Reference yaw rate generation means as reference turning momentum generation means, 6 ... Yaw movement correction means as turning movement correction means, 8 ... Reference value generation means, H ... Steering handle

Claims (1)

(57) [Claims] 1. A turning momentum detecting means (2) for detecting a turning momentum generated when a vehicle turns, a vehicle speed detector (3) for detecting a vehicle speed, and a steering angle of a steering wheel (H). A turning angle sensor (4); a reference turning momentum generating means (5, 5 ') for outputting a reference turning momentum based on at least outputs of the vehicle speed detector (3) and the turning angle sensor (4); Reference value generating means (8) for determining the reference value of the output deviation of the turning momentum generating means (5, 5 ') and the turning momentum detecting means (2) according to the output of the turning angle sensor (4); A turning motion correction for controlling the turning motion of the vehicle when the output deviation of the momentum generating means (5, 5 ') and the turning momentum detecting means (2) is larger than the reference value determined by the reference value generating means (8). Vehicle comprising means (6) and; Of turning motion control apparatus.