JP2581930B2 - Vehicle turning motion control device - Google Patents

Description

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

(2) Conventional Art Conventionally, an anti-lock brake has been known for controlling a turning motion of a vehicle.

(3) Problems to be Solved by the Invention However, antilock brakes focus on the control performance of the antilock brake, and the exercise performance is not
It only prevents the decrease in tire lateral force.

Therefore, the present applicant detects the yaw rate as the turning momentum based on the speed difference between the free rolling wheels of the vehicle, the reference yaw rate as the reference turning momentum determined based on the history of the detected yaw rate and the steering angle, and the detected yaw rate. A turning motion control device has been proposed in which the engine output is reduced by fuel cut when the deviation is larger than an allowable value.

However, in the turning motion control device, the driving force is turned on and off.
Since the off control is performed, depending on the permissible value, the control responsiveness is deteriorated, and the torque difference when the engine output is reduced is large, which may cause discomfort. Therefore, if the allowable value is set small, there is a risk of excessive control.

The present invention has been made in view of such circumstances,
An object of the present invention is to provide a vehicle turning motion control device that enables more precise turning motion control.

B. Configuration of the Invention (1) Means for Solving the Problems The present invention device is a turning momentum detecting means for detecting a turning momentum generated when the vehicle turns, and a turning angle sensor for detecting a turning angle of a steering handle. Reference turning momentum generating means for outputting a reference turning momentum based on the output of the turning angle sensor; a first reference value for determining an output deviation of the reference turning momentum generating means and the turning momentum detecting means; Reference value generating means for determining a second reference value which is larger than the first reference value and which is changed in accordance with over-steering and under-steering; when the output deviation becomes equal to or more than the first reference value, A first control mode for reducing the fuel concentration in the supplied air-fuel mixture and a second control mode for shutting off fuel supply to the engine when the output deviation becomes equal to or greater than a second reference value. Turning motion correcting means for controlling turning motion of the vehicle.

(2) Operation According to the above configuration, the deviation between the detected turning momentum and the desired turning momentum based on the turning angle (reference turning momentum) exceeds the reference value, so that the turning momentum becomes an undesirable value. Can be detected, whereby the turning movement can be controlled. In addition, when the deviation is equal to or greater than the first reference value, the turning motion correcting means decreases the fuel output of the air-fuel mixture supplied to the engine to gradually decrease the engine output. When the second reference value is larger than the second reference value, the fuel supply to the engine is shut off and the engine output is rapidly reduced, so that the control responsiveness when the deviation is large can be improved, and When the deviation is small, excessive control can be prevented from occurring. In addition, even when the deviation is large, the engine output is gradually reduced by decreasing the fuel concentration, followed by a rapid decrease in the engine output by shutting off the fuel supply. It is possible to avoid a large torque difference from occurring suddenly. Further, by changing the second reference value in accordance with the over-steering and the under-steering, the timing of shutting off the fuel supply is changed between the time of the over-steering and the time of the under-testing to prevent the occurrence of the over-control state. More precise turning motion control becomes possible.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, in FIG. 1 showing one embodiment of the present invention, the speed sensors 1, 1r are individually provided for the left and right free rolling wheels Wl, Wr of the vehicle. The wheel speeds Vl, Vr detected by the speed sensors 1, 1r are input to a yaw rate detecting means 2 as a turning momentum detecting means and a vehicle speed detector 3, respectively. A steering angle sensor 4 is attached to the steering wheel H. The steering angle δ detected by the steering angle sensor 4 and the vehicle speed Vv obtained by the vehicle speed detector 3 are provided.
The history of the yaw rate y as the turning momentum obtained by the yaw rate detecting means 2 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. Also the yaw correction means 6, the deviation between the yaw rate y and the reference yaw rate y _b Dr
(= Y−y _b ) is obtained, and the deviation Dr and the reference yaw rate are obtained.
y _b is 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 steering angle δ from the steering angle sensor 4.
Is input to the reference value generating means 8 respectively. The vehicle is 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 a front wheel or a rear wheel. The output of the switch 9 is Input to the discriminating circuit 10 and the driving wheel discriminating circuit 10
Is input to the reference value generating means 8. The reference value generating means 8 inputs the first and second reference value signals, which change according to each input signal, to the yaw motion correcting means 6, and changes the control mode of the yaw motion correcting 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 for storing the output history of the multiplication circuit 12, and a history storage circuit 15 for storing the output history of the filter 13. The subtraction circuit 11 includes the speed sensor 1
, 1r to obtain a difference r (= Vr−Vl) between the wheel speeds Vl, Vr.
, The yaw rate approximate value y ′ (= r ×
d) is obtained. Where the proportionality constant d is the free rolling wheels Wl, Wr
, For example, d = 1. Filter
13 is the wheel speed Vl, Vr due to the vibration of the vehicle suspension
In this case, a recursive filter is used. Here, the fluctuation of the wheel speeds Vl and Vr due to resonance with the vibration of the suspension during rough road running is about 10 Hz, and the frequency range of the yaw rate used for controlling the vehicle motion is 0 to 2H.
Since it is z, the filter 13 filters the approximate value y 'of the yaw rate with the attenuation range of 2 Hz or more. 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 current value and the previous value of the cycle because the filtering operation is repeated in a constant cycle, and the previous value of the approximate value y ′ of the yaw rate, the value before the previous time. It is input from the storage circuit 14 to the filter 13, and the previous value of the yaw rate y, the value before the previous one, and so on.
Is input from the history storage circuit 15 to the filter 13.

The vehicle speed detector 3 outputs the vehicle speed Vv based on the wheel speeds Vl, Vr detected by the two speed sensors 1, 1r. Output as speed 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 are constants a ₁ , a ₂ , b ₁ , b ₂ used in the operation in the operation circuit 18
A vehicle speed detector is 3 obtained in according to the vehicle speed Vv which selected, the constants a _1, which are defined as shown in FIG. 2 for example according to the respective vehicle, a _2, b ₁ , 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. Arithmetic circuit 18, and calculates a history of yaw rate y of the history storage circuit 15 in the yaw rate detection means 2, a reference yaw rate y _b is currently to be based on the history of the turning angle δ from the history storage circuit 17 Yes,
An operation according to the following equation (2) is performed.

y _b = −a ₁・ y _n-1 −a ₂・ y _n-2 + b ₁・ δ _n-1 + b ₂・ δ _n-2 ...
(2) The yaw movement correcting means 6 calculates a deviation Dr (= y-y _b ) between the yaw rate y obtained by the yaw rate detecting means 2 and the reference yaw rate y _b obtained by the reference yaw rate generating means 5. 19 and the absolute value conversion circuit that converts the deviation Dr to an absolute value
20, first and second comparators 21 and 22 to which the output of the absolute value conversion circuit 20 is input to the inverting terminals, and a drive export torque control circuit 23 to which the output terminals of both comparators 21 and 22 are connected. Consists of The drive export force torque control circuit 23 controls, for example, fuel supplied to the engine, and includes a first comparator 21
When the output of the second comparator 22 is at a low level, the fuel supply amount is reduced to lower the mixture concentration, and when the output of the second comparator 22 is at a low level, the fuel supply is cut off.

A steering characteristic determination means 7, a reference yaw rate y _b from a reference yaw rate generating means 5, and the deviation Dr from the deviation calculation circuit 19 is input, a steering characteristic determination means 7
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. .

The reference value generating means 8 includes a vehicle speed Vv from the vehicle speed detector 3, a turning angle δ from the turning angle sensor 4, a determination result from the drive wheel determination circuit 10, and a determination result from the steering characteristic determination means 7. Are input, and
The reference value generating means 8 outputs an output terminal C connected to the non-inverting terminal of the first comparator 21 and a second reference value to output a first reference value, based on the input signals. Second
A signal is output from an output terminal D connected to the non-inverting terminal of the comparator 22, respectively. That is, when the vehicle is a front-wheel drive vehicle and the turning angle δ is relatively small, the reference value generation means 8 outputs the output value of the output terminal C based on the vehicle speed Vv and the result of the determination by the steering characteristic determination means 7. (First reference value) is set, for example, as shown by the solid line in FIG. 3, and the output value (second reference value) of the output terminal D is set, for example, as shown by the broken line in FIG. Is set to be larger than the output value of. 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.
Multiplied by l) by the proportionality constant d and then filtered by the filter 13, it is possible to easily obtain the yaw rate y having no practical problem by eliminating the influence of the vehicle suspension.

Such a yaw rate y estimated, 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 output terminal of the reference value generating means 8 When the first and second reference values from C and D are exceeded, the drive export torque control circuit 23 is operated to control the yaw motion by detecting in advance that the vehicle turns in an undesirable direction. be able to.

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, oversteering tends to occur when 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, oversteering is prevented by reducing the drive force can do. 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 value from the output terminal D, that is, the second reference value is set differently according to the result of the discrimination by the steering characteristic discriminating means 7.
For example, when an over-steering tendency occurs in a front-wheel drive vehicle, the output value from the output terminal D is set smaller during over-steering than during under-steering as shown in FIG. Before the steering state is exhibited, the vehicle speed can be reduced to a stable low vehicle speed. In each of the oversteering state and the understeering state, the first comparator 21 is output before the output of the second comparator 22 becomes low. Becomes low level, the drive export torque control circuit 23 acts to reduce the concentration of the air-fuel mixture to the engine, and the drive power gradually decreases. Therefore, it is possible to prevent the overcontrol state from being caused by a gradual decrease in the driving force.

Also, when the steering angle δ when the vehicle low speed of the character is large, whereas the steering characteristic of the vehicle becomes nonlinear, for reference yaw rate y _b generated by the reference yaw rate generating means 5 is linear, the reference yaw rate y _b Although the deviation Dr between the yaw rate y and the yaw rate y increases, the value input from the reference value generating means 8 to the first and second comparators 21 and 22 indicates that the vehicle speed Vv is high as shown in FIG. Therefore, excessive control at low vehicle speeds can be prevented and insufficient control at high vehicle speeds can be prevented.

Further, the output value from the reference value generating means 8 is set so as to become smaller as the turning angle δ becomes larger, so that the first comparator 21 or the second comparator becomes larger when the turning angle δ is larger.
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.

In addition, the drive export torque control circuit 23 performs the first control mode for reducing the concentration of the air-fuel mixture to the engine and the second control mode for shutting off the fuel supply to the engine by using the output from the reference value generating means 8. , It is possible to perform more precise control as compared with the control of only shutting off the fuel supply, and it is possible to eliminate discomfort due to a large torque difference and prevent excessive control.

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 of the reference yaw rate y _b inputted from the history storing circuit 25
and _{y bn-1, y bn-} 2, history [delta] _n-1 of [delta] turning angle from the history accumulation circuit 17, a reference yaw rate y _b is calculated by the [delta] _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.

In the above-described embodiment, the reference yaw rate y _b is obtained by the calculation based on the history ( _{n−1, n−2} ) of the previous time and the previous _two times.
Alternatively, it may be determined based on the history ( _{n-1, n-2, n-3,} ...).

C. Effects of the Invention As described above, the device of the present invention includes a turning momentum detecting means for detecting a turning momentum generated when the vehicle turns, a turning angle sensor for detecting a turning angle of a steering wheel, and a turning angle sensor. Reference turning momentum generating means for outputting a reference turning momentum based on the output; a first reference value for determining an output deviation of the reference turning momentum generating means and the turning momentum detecting means; and a value larger than the first reference value. Reference value generating means for determining a second reference value changed in accordance with over-steering and under-steering; fuel in the air-fuel mixture supplied to the engine when the output deviation is equal to or greater than the first reference value A first control mode for reducing the concentration,
Turning control means for controlling turning motion of the vehicle having a second control mode for shutting off fuel supply to the engine when the output deviation becomes equal to or greater than a second reference value. Therefore, it is possible to control the turning motion by detecting that the vehicle turns in an undesirable direction. In addition, when the output deviation of the reference swing momentum generation means and the swing momentum detection means is equal to or more than the first reference value, the fuel concentration in the air-fuel mixture supplied to the engine is reduced to gradually reduce the engine output, and Is greater than or equal to a second reference value greater than the first reference value, the fuel supply to the engine is shut off and the engine output is rapidly reduced, so that the deviation of the turning momentum from the reference turning momentum can be compared. It is possible to improve the control responsiveness when the target is large, and it is possible to prevent excessive control from occurring when the deviation of the turning momentum from the reference turning momentum is relatively small. In addition, the rapid decrease in engine output caused by shutting off the fuel supply follows the gradual decrease in engine output caused by decreasing the fuel concentration. This can be avoided and the driver does not feel uncomfortable. Second
The reference value of is changed according to over-steering and under-steering, so that the timing of shutting off the fuel supply is changed between over-steering and under-steering to prevent the occurrence of over-control state and more precise turning Motion control can be performed.

[Brief description of the 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 an output characteristic of a constant selection circuit, FIG. 3 is a graph showing an example of an output characteristic of a reference value generating means, and FIG. 4 is another example of the present invention. FIG. 2 is an overall block diagram of the embodiment. 2: turning momentum detection means, 4: turning angle sensor, 5, 5 '...
Reference turning momentum generation means, 6 ... turning motion correction means, 8 ...
Reference value generating means, H ... steering wheel

Claims (1)

(57) [Claims] A turning momentum detecting means for detecting a turning momentum generated when the vehicle turns, a turning angle sensor for detecting a turning angle of a steering wheel, and a turning angle sensor. A reference swing momentum generating means (5, 5 ') for outputting a reference swing momentum based on the output of 4); an output deviation of the reference swing momentum generating means (5, 5') and a swing momentum detecting means (2) is determined. Reference value generating means (8) for defining a first reference value for performing the control and a second reference value that is larger than the first reference value and that is changed in accordance with over-steering and under-steering; A first control mode for decreasing the fuel concentration in the air-fuel mixture supplied to the engine when is equal to or more than a first reference value; and a control mode for the engine when the output deviation is equal to or more than a second reference value. The second to shut off the fuel supply Turning motion control apparatus for a vehicle, characterized in that it comprises a; control mode and the turning motion correction means (6) for controlling the turning motion of the vehicle has a.