JPH0194031A - Yawing controller for vehicle - Google Patents

Abstract

PURPOSE:To enable proper control in conformity with a driving force distribution by varying a control characteristic according to a distribution ratio of driving force by a desirable yaw rate based on the detected yaw rate and a steering angle. CONSTITUTION:A yaw rate (y) secured by a yaw rate detecting means 2 and a reference yaw rate (yb) generated out of a reference yaw rate generating means 5 both are inputted into a yawing correction means 6. A deviation Dr between the yaw rate (y) and the reference yaw rate (yb) and the reference yaw rate (yb) both are inputted into a steering characteristic discriminating means 7. The discriminated result of a driving force discriminating means 10, which discriminates whether a driving force distribution ratio, namely, either of front and rear wheels bears 100% driving force or not, is inputted into a control characteristic correcting means 8 which inputs a signal to vary according to each input signal into the yawing correction means 6, thereby varying a control mode of the yawing correction means 6.

Description

[Detailed description of the invention] A0 Purpose of invention (1) Industrial application fields The present invention relates to a yaw motion control device for a vehicle.

(2) Prior Art Conventionally, anti-lock brakes have been known as devices for controlling the yaw motion of a vehicle.

(3) Problems to be solved by the invention However, anti-lock brakes focus their control on braking performance, and in terms of driving performance, they only prevent a decrease in tire lateral force. .

Therefore, the present applicant detected the yaw rate based on the speed difference of the free rolling wheels of the vehicle, and also controlled the yaw rate of the engine based on the deviation between the detected yaw rate and the reference yaw rate determined based on the detected yaw rate and steering angle history. A yaw motion control device has already been proposed which performs this by reducing the output.

However, some vehicles can switch between two-wheel drive and four-wheel drive, and some vehicles can adjust the drive power distribution ratio between the front and rear wheels. If the distribution changes, naturally the control characteristics should also change, but the above-mentioned yaw motion control device does not take such consideration.

The present invention has been made in view of the above circumstances, and it is possible to appropriately control yaw motion by changing control characteristics depending on which wheel is being driven by the vehicle or the driving force distribution ratio. An object of the present invention is to provide a yaw motion control device for a vehicle.

B1 Structure of the Invention (1) Means for Solving Problems The device of the present invention comprises: yaw rate detection means for detecting the yaw rate of the vehicle; a turning angle sensor for detecting the turning angle of a steering wheel; and a turning angle sensor. a reference yaw rate generating means for outputting a reference yaw rate based on the output of the reference yaw rate; a driving force determining means for detecting the driving force distribution ratio between the front and rear wheels; A yaw motion modification means for controlling the motion; and a control characteristic modification means for changing the control characteristics of the yaw motion modification means based on the output of the driving force determination means.

(2) Effect According to the above configuration, it is possible to detect that the yaw rate has reached an undesirable value based on the detected yaw rate and the desired yaw rate based on the steering angle, and thereby it is possible to control the yaw movement. In addition, the control of the yaw motion can be changed according to the output of the driving force determining means, so it is possible to control the yaw motion appropriately depending on whether the front or rear wheels are the driving wheels or the driving force distribution. becomes possible.

(3) Examples Examples of the present invention will be explained below with reference to the drawings.
First, in FIG. 1 showing an embodiment of the present invention, speed sensors IL1r are individually attached to left and right free rolling wheels WE, Wr of a vehicle, and these speed sensors 142. The wheel speed Vj2 detected at lr. Vr is input to the yaw rate detection means 2 and the vehicle speed detector 3, respectively. Further, 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 2, and the yaw rate detection means 2 The history of the yaw rate y obtained in is inputted to the reference yaw rate generating means 5.

The yaw rate y obtained by the yaw rate detection means 2 and the reference yaw rate yb generated from the reference yaw rate generation means 5
are respectively input to the yaw motion correction means 6. Further, the yaw motion correction means 6 obtains the deviation Dr (=yyb) between the yaw rate y and the reference yaw rate yb, and this deviation D
r and the reference yaw rate y are input to the steering characteristic determining means 7. The determination result of the steering characteristic determining means 70, the vehicle speed Vv from the vehicle speed detector 3, and the steering angle δ from the steering angle sensor 4 are determined by the control characteristic modifying means 8.
are input respectively. Also, this vehicle has output depending on whether the drive wheels are the front wheels or the rear wheels! A switch 9 is provided for switching the pressure bell between a high level and a low level, and the output of this switch 9 is transmitted to the driving force determining means 1.
0, and the driving force distribution ratio, that is, the determination result of the driving force determining means 10 that determines which of the front and rear wheels will share 100% of the driving force is input to the control characteristic modifying means 8. The control characteristic modifying means 8 inputs a signal that changes according to each input signal to the yaw motion modifying means 6, and changes the control mode of the yaw motion modifying means 6.

The yaw rate detection means 2 includes a subtraction circuit 11 and a multiplication circuit 1.
2, a filter 13, a history accumulation circuit 14 that accumulates the output history of the multiplier circuit 12, and a history accumulation circuit 15 that accumulates the output history of the filter 13. The subtraction circuit 11 is
Speed sensor 11! ,,wheel speed Vf detected at 1r,
The difference r (=Vr-Vj) of Vr is obtained, and by multiplying the difference r by a constant proportionality constant d in the multiplication circuit 12, an approximate value y' (=rXd) of the yaw rate can be obtained.

Here, the proportionality constant d is the free rolling wheel Wj! , Wr, for example, d=1. The filter 13 detects wheel speeds Vffi and Vr due to vibrations of the vehicle suspension.
A recursive filter is used. Here, the wheel speed vl is due to resonance with the vibration of the suspension while driving on a rough road.

Since the fluctuation of Vr is about 10 Hz and the frequency range of the yaw rate used to control vehicle motion is 0 to 2 Hz, the filter 13 filters the approximate value y' of the yaw rate using 2) [z or more as the attenuation range. In other words, in the filter 13, when the output value is yi, the next (1st
) is calculated.

y, = α1°'In-+ +α:・y++-t+α3・
)'R-3+β1・yI%'+βg')'e-+' +β3 ・y l, -3' ・
(1) Here, α1...α3. β, . . . β are constants determined by experimental results. Also, subscript...
... Since the filtering calculation is repeated in a certain cycle, n-ff represents the current value, previous value, etc. of that cycle, and the previous value, the value before the previous time, etc. of the approximate value y' of the yaw rate are accumulated in the history. The previous value of yaw rate y, the value before the previous time, etc. are input from the circuit 14 to the filter 13, and the vehicle speed detector 3 receives the wheel speeds detected by both speed sensors 1ffi and 1r. It outputs the vehicle speed Vv based on Vffi and Vr, for example, both axle speeds Vj! , Vr is output as the vehicle speed Vv.

The reference yaw rate generating means 5 includes a constant selection circuit 16, a history accumulation circuit 17, and an arithmetic circuit 18. The constant selection circuit 16 selects a constant al used in calculations in the calculation circuit 18.
+ am l bl + bl is selected according to the vehicle speed Vv obtained by the vehicle speed detector 3, and each constant al+ a determined as shown in FIG. 2, for example, according to each vehicle ! + bl + bl
The value of is input to the arithmetic circuit 18.

Further, the history accumulation circuit 17 inputs the history of the steering angle δ detected by the steering angle sensor 4 to the arithmetic circuit 18.

The calculation circuit 18 calculates the current reference yaw rate y based on 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. Yes, next (2)
Calculation according to the formula % Formula % The yaw movement correction means 6 includes a deviation calculation circuit 19 that obtains the deviation Dr (-yyh) between the yaw rate y obtained by the yaw rate detection means 2 and the reference yaw rate yb obtained by the reference yaw rate generation means 5. , an absolute value converting circuit 2o that converts the deviation Dr into an absolute value, and first and second comparators 21 and 22 to which the output of the absolute value converting circuit 20 is inputted to the inverting terminal, respectively.
It consists of a drive output torque control circuit 23 to which the output ends of both comparators 21 and 22 are connected. The drive output torque control circuit 23 controls, for example, the fuel supplied to the engine, and when the output of the first comparator 21 is at a low level, the fuel supply amount is reduced to thin the mixture concentration, and the first 2. When the output of the comparator 22 is at a low level, the fuel supply is cut off.

The steering characteristic determining means 7 receives the reference yaw rate yb from the reference yaw rate generating means 5 and the deviation calculating circuit 1.
The deviation Dr from 9 is input to the steering characteristic determining means 7.

The steering characteristics are determined based on y. That is, the steering characteristic determining means 7 has predetermined criteria shown in Table (1) below.

Table (1) In this table (1), the symbol ○ indicates oversteering, and the symbol U indicates understeering, and the results determined based on this table (1) are the steering characteristic determination means. Output from 7.

The control characteristic modification means 8 receives the vehicle speed Vv from the vehicle speed detector 3, the steering angle δ from the steering angle sensor 4, the determination result from the driving force determination means 10, and the determination result from the steering characteristic determination circuit 7. Based on these input signals, the control characteristic modifying means 8 outputs the output terminal C connected to the non-inverting terminal of the first comparator 21 and the non-inverting terminal of the second comparator 22. A signal is output from each output terminal connected to the inverting terminal. That is, when the vehicle is a front-wheel drive vehicle and the steering angle δ is relatively small, the control characteristic modifying means 8 adjusts 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. is set, for example, as shown by the solid line in FIG. 3, and the output value of the output terminal is set, for example, as shown by the broken line in FIG. Further, when the vehicle is a rear wheel drive vehicle, output values different from those shown in Fig. 3 are set, and when the steering angle δ becomes relatively large, the output values of output terminals C and D are set as shown in Fig. 3 above. Each value is set to be smaller than the value.

Next, to explain the operation of this embodiment, the yaw rate y of the vehicle is determined by the speed difference (V
The yaw rate y is obtained by multiplying r-Vff) by the proportionality constant d and then filtering with the filter 13, which eliminates the influence of the vehicle suspension and poses no problem in practical use.
can be easily obtained.

The absolute value of the deviation Dr between the yaw rate y estimated in this way and the reference yaw rate yb calculated as the current value based on the steering angle δ and the history of the yaw rate y is output to the output terminal C of the control characteristic correction means 8. .

For example, in a front-wheel drive vehicle, if excessive driving force is applied while turning the steering wheel, an understeering tendency occurs, and when it is detected that the vehicle has turned in an undesirable direction, the first and second comparators 21. Drive wheel torque control circuit 23 according to the output of 22
operates to reduce engine output. The driving force of the drive wheels decreases in accordance with this decrease in engine output, and the limit lateral force of the drive wheels increases instead, making it possible to prevent the above-mentioned understeering.

On the other hand, in the case of a rear-wheel drive vehicle, oversteering tends to occur when excessive driving force is applied, but in this case as well, oversteering is prevented by reducing the driving force, as in the case of front-wheel drive vehicles. can do.

When the actual yaw rate y approaches the reference yaw rate y by reducing the engine output in this manner, the engine output reduction is canceled and normal engine output control is resumed.

Moreover, the control characteristic modifying means 8 has its output terminals C and D.
The output value of
As shown in the figure, since the output value from output terminal C is set smaller than the output value from output terminal C, it is possible to maintain a low vehicle speed at which the vehicle body stabilizes before the vehicle body exhibits an oversteering condition. In both oversteering and understeering states, the output of the first comparator 21 becomes low level before the output of the second comparator 22 becomes low level, and the drive output torque control circuit 23 controls the output power to the engine. It works to thin the air-fuel mixture concentration, and the driving force gradually decreases. Therefore, it is possible to avoid an overcontrol state from occurring due to a gradual decrease in the driving force.

Furthermore, when the steering angle δ is large at low vehicle speeds, the steering characteristics of the vehicle become non-linear, whereas the reference yaw rate yb generated by the reference yaw rate generating means 5 is linear, so the reference yaw rate yb and Although the deviation Dr from the yaw rate y becomes large, the first and second comparators 21.2
The value from the control characteristic correction means 8 that is input manually in step 2 is set to decrease as the vehicle speed Vv increases, as shown in FIG. In addition to preventing control, insufficient control at high vehicle speeds can also be prevented.

Furthermore, since the output value from the control characteristic correction means 8 is set to become smaller as the steering angle δ increases, the output value of the first comparator 21 or the second comparator 22 is smaller when the steering angle δ is large. The output is likely to be at a low level, and therefore, it is possible to prevent insufficient control due to the increase in inertia of yaw motion when the steering wheel H is turned to a large angle.

Furthermore, since the output value from the control characteristic modifying means 8 changes depending on whether the front wheels or the rear wheels are the driving wheels, the output value from the control characteristic modifying means 8 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 output torque control circuit 23 switches between a control mode that reduces the mixture concentration to the engine and a control mode that cuts off the fuel supply to the engine, depending on the output from the control characteristic modification means 8. Compared to control only by cutting off fuel supply, more precise control is possible, and 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, and parts corresponding to the embodiment of FIG. 1 are given the same reference numerals.

The calculation circuit 18' in the reference yaw rate generating means 5' performs calculation according to the following equation (3) to obtain the reference yaw rate Yb.

Vb=a+ ° Ybn-+ ax” Vh
n-wealth+b, -δn-++bz・δn-1...(3)
That is, the reference yaw rate y obtained by the calculation circuit 18'
The history of reference yaw rate y, y-+, y-2 inputted from this history accumulation circuit 19, and the turning angle δ from the history accumulation circuit 17 are stored in the history accumulation circuit 19. The reference yaw rate yb is calculated based on the history δ7-I, δ, , -2.

Further, the driving force discriminating means 10' includes a driving force distribution control circuit 2.
A signal from 4 is input. The driving force distribution control circuit 24 controls the driving force distribution ratio between the front wheels and rear wheels of the vehicle, and the driving force distribution ratio is detected by the driving force determining means 10' and inputted to the control characteristic modifying means 8. Ru.

According to this embodiment, in addition to producing the same effects as in the previous embodiment, the reference yaw rate generating means 5' calculates the reference yaw rate ub based on the history of the reference yaw rate y, so that the calculation formula is It is simple and can reduce costs, and can avoid deterioration in controllability caused by complicated arithmetic expressions. By changing the M control characteristic in accordance with a change in the driving force half ratio, it is possible to perform appropriate yaw motion control in accordance with a change in the driving force distribution ratio.

As yet another embodiment of the present invention, the vehicle speed detector 3 may output the average value of the wheel speeds Vf and Vr of both free transfer wheels Wf and Wr as the vehicle speed Vv.

In addition, in the above embodiment, the deviation Dr of the reference yaw rate) yb and the actual yaw rate y was compared with the reference value, but the engine output (
For example, the throttle opening may be controlled. Furthermore, the reference yaw rate y.

History up to the previous time and the time before the previous time (11-1+++-2)
It was calculated using the calculation, but the history beyond that (n-1+n-
4+n-2,...) may be used.

C0 Effects of the Invention As described above, the device of the present invention includes: a yaw rate detection means for detecting the yaw rate of the vehicle; a turning angle sensor for detecting the turning angle of the steering wheel; and a reference yaw rate based on the output of the turning angle sensor. a reference yaw rate generating means for outputting; a driving force determining means for detecting the driving force distribution ratio between front and rear wheels; The control characteristic modifying means changes the control characteristics of the yaw motion modifying means based on the output of the driving force determining means, so that the yaw motion can be controlled by detecting that the vehicle is turning in an undesirable direction. It becomes possible to
Moreover, since the control n characteristic is changed according to the distribution ratio of the driving force, appropriate control according to the distribution of the driving force can be performed.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention,
FIG. 1 is an overall block diagram, FIG. 2 is a graph showing an example of the output characteristics of the constant selection circuit, FIG. 3 is a graph showing an example of the output characteristics of the control characteristic correction means, and FIG. FIG. 1 is an overall block diagram of an embodiment. 2... Yaw rate detection means, 4... Steering angle sensor,
5.5'... Reference yaw rate generation means, 6... Yaw motion correction means, 8... Control characteristic correction means, 10.10
'...Driving force determination means, H...Steering handle Patent Applicant: Honda Motor Co., Ltd. Representative Patent Attorney Kendo Ochiai 1) Takahide Naka1
, Incident Display 1986 Patent Application No. 250169 2 Invention 0 Name Vehicle (7) 'i? - Motion control device 3, relation to the case of the person making the amendment Patent applicant name (532) Honda Motor Co., Ltd. 5, "Detailed description of the invention" column of the specification to be amended, and Figure 1 of the drawings And in Figure 4 Correction Contents 1, No. 5, Line 13 of the Specification, "Vehicle Speed Detector 2" is corrected to "Vehicle Speed Detector 3." 2. On page 12, line 9 of the specification, "discrimination circuit 7" is corrected to "discrimination means 7." 3. In the third line of page 13 of the specification, "Figure 4" is corrected to "Figure 3." 4. In the 16th line and last line of page 18 of the specification, the words "history accumulation circuit 19" are corrected to "history accumulation circuit 25." 5. Figures 1 and 4 of the drawings are corrected as shown in the attached sheet. that's all

Claims (1)

[Claims] Yaw rate detection means for detecting the yaw rate of the vehicle; a steering angle sensor for detecting the turning angle of the steering wheel; reference yaw rate generating means for outputting a reference yaw rate based on the output of the steering angle sensor; front and rear wheels. a driving force determining means for detecting a driving force distribution ratio of; a yaw motion correcting means for controlling the yaw motion of the vehicle based on the outputs of the reference yaw rate detecting means and the yaw rate detecting means; based on the output of the driving force determining means; A yaw motion control device for a vehicle, comprising: control characteristic modifying means for changing control characteristics of the yaw motion modifying means.