JPS6331863A - Slip controller for automobile - Google Patents

Abstract

PURPOSE:To make slip control into a gentle something and improve its stability, by controlling a control speed in a direction of reducing the torque given to driving wheels or its controlled variable so as to make it smaller as compared with the time of rectilinear state when a vehicle is detected to be in a turning state. CONSTITUTION:The above captioned controller controls a control regulating device C by a slip controlling device B so as to cause the detected slip value to become the desired value on the basis of output of a slip detecting device A detecting a slip state to a road surface of driving wheels. With this control, the torque given to the driving wheels is regulated, preventing a slip from excessively growing. In this case, there is provided with a turning detecting device D which detects the turning state of a vehicle. And, whe a fact that the vehicle is in a turning state is detected by this turning detecting device D, a control speed in the direction of reducing the torque given by a torque reducing device E for its controlled variable is controlled so as to make it smaller as compared with the time when it is rectilinear running state by the control regulating device C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides an automobile slip control system that prevents excessive slip of the drive wheels relative to the road surface by controlling the torque applied to the drive wheels. 〃Regarding the control device.

(Prior Art) Preventing the drive wheels from slipping excessively on the road surface is effective in effectively obtaining the propulsion force of the vehicle and in terms of safety by preventing spin. In order to prevent excessive slippage of the driving wheels, it is sufficient to reduce the torque applied to the driving wheels, which causes the slippage.

Conventionally, methods for performing this type of slip control are disclosed in Japanese Patent Application Laid-Open No. 58-16948 or Japanese Patent Application Laid-Open No. 60-56.
There is one shown in Publication No. 662.

Both of the technologies disclosed in these publications utilize the application of braking force to the drive wheels by the brake and the reduction of the torque generated by the engine to reduce the torque applied to the drive wheels. ing. More specifically, JP-A-58
- In the case of Publication No. 16948, when the slip of the drive wheels is small, only the braking of the drive wheels is performed, but when the slip of the drive wheels becomes large, in addition to the braking of the drive wheels, the engine is It is designed to reduce torque. In addition, in the device disclosed in Japanese Patent Application Laid-Open No. 60-56662, when the slip of only one side of the left and right drive wheels is large, braking is applied only to the drive wheel on one side with a large slip, while the left and right drive wheels are braked. When the slips of both drive wheels are large, braking is applied to both drive wheels and the torque generated by the engine is reduced.

(Problems to be Solved by the Invention) By the way, when the vehicle is in a turning state, the vehicle is in an unstable state. Therefore, if slip control during turning is not performed appropriately, there is a risk of inducing a spin or the like.

Therefore, when the vehicle is in a turning state, it is desirable from the viewpoint of improving safety that the slip control be controlled appropriately.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a slip control device for an automobile that changes the contents of slip control depending on whether the vehicle is in a turning state or not.

(Means and effects for solving the problem) In order to achieve the above-mentioned object, in the present invention, rapidly performing slip control during turning, especially control in the direction of reducing the torque of the driving wheels, In consideration of the undesirable result of inducing the wheel, when the vehicle is turning, the torque applied to the drive wheels is controlled to be reduced more slowly than when the vehicle is traveling straight. That is, the 20th
As shown in 13J, the turning state of the vehicle is detected based on an automobile slip control device that prevents excessive slip of the driving wheels against the road surface by controlling the torque applied to the driving wheels. a turning detection means; and a control adjustment means that receives a signal from the turning detection means and reduces a control speed or a controlled amount in a direction to reduce the applied torque when the vehicle is in a turning state compared to when the vehicle is in a straight forward state. The configuration includes the following.

With this configuration, slip control is performed gently when the vehicle starts turning, thereby improving safety. - On the other hand, when the vehicle is traveling straight, relatively steep slip control is performed, resulting in improved slip convergence.

(Example) Hereinafter, an example of the present invention will be described based on the attached drawings.

Overview of overall configuration In Fig. 1, a car 1 has left and right front wheels 2 that serve as driving wheels.
, 3, and left and right rear wheels 4.5 serving as driven wheels. An engine 6 as a power source is mounted on the front of the automobile I, and the torque generated by the engine 6 passes through a clutch 7, a transmission 8, and a differential gear 9, and then is transmitted to left and right drive shafts 10.11. The power is transmitted to the left and right front wheels 2.3 as driving wheels. In this way, the automobile 1 is of the FF type (front drive).

The engine 6 as a power source has its intake passage 12
Load control, that is, control of generated torque, is performed by a throttle/help 13 disposed in the engine. More specifically, the engine 6 is a gasoline engine, and the generated torque changes depending on the change in the intake air amount, and the intake air amount is adjusted by the throttle valve 13. Then, the throttle valve 13 is operated by the throttle actuator 14.
Opening and closing is controlled electromagnetically. In addition, as the throttle actuator 14, for example, DC7~
Alternatively, it may be constructed of an appropriate step motor, a step motor, a motor driven by fluid pressure such as oil pressure, and electromagnetically controlled.

Each wheel 2-5 has a brake 21, 22, 23, respectively.
Alternatively, 24 are provided, and each of the brakes 21 to 24 is a disc brake. As is known, this disc brake includes a disc 25 that rotates together with the wheel and a caliper 26. This caliper 2
6 holds the brake band and is equipped with a wheel cylinder, and the brake pad is applied to the disc 2 with a force corresponding to the magnitude of the brake fluid pressure supplied to the wheel cylinder.
5, braking force is generated.

The mask cylinder 27 as a brake fluid pressure generation source is 2
It is of a tandem type having two discharge ports 27a and 27b. A bulb 17 extending from the discharge port 27a.・-K piping 28
The pipe is branched into two branch pipes 28a and 28b in the middle.
The branch pipe 28a is connected to the brake 22 for the right front wheel (the wheel cylinder thereof), and the branch pipe v28b is connected to the brake 2 for the left rear wheel.
Connected to 3. In addition, the brake distribution v29 extending from the discharge port 27b has two branch pipes 29a and 29b on the way.
The branch pipe 29a is connected to the brake 21 for the left front wheel, and the branch pipe 29b is connected to the brake 24 for the right rear wheel.
has been done. In this way, the brake arrangement and pipe system are of the so-called two-system X type. Branch pipes 28a and 29a for brakes 21 and 22 for front wheels, which are driving wheels.
includes an electromagnetic hydraulic pressure control valve 3 as a braking force adjustment means.
0 or 31 is connected. Of course, the brake fluid pressure generated in the mask cylinder 27 depends on the amount of depression of the brake pedal 32 (8 depression force) by the driver.

Brake Hydraulic Pressure Control Circuit As shown in FIG. 2, each of the hydraulic pressure control valves 30, 31 has a cylinder 41 and a piston 42 that is slidably inserted into the cylinder 41. The piston 42 defines the inside of the cylinder 41 into a variable volume chamber 43 and a control chamber 44 . This variable volume chamber 43 is
It serves as a passageway for brake fluid pressure from the mask cylinder 27 to the brake 21 (22). Therefore, by adjusting the displacement position of the piston 42, the volume of the variable volume chamber 43 is changed, and the brake 21 (22)
This means that the brake fluid pressure can be increased, decreased or maintained.

The piston 42 is constantly urged by a return spring 45 in a direction in which the volume of the variable volume chamber 43 increases. Also, for the piston 42.

A check valve 46 is integrated. When the piston 42 is displaced in the direction of decreasing the volume of the variable volume chamber 43, the chain valve 46
Inflow r to 3: Close the J side. As a result, the brake fluid pressure generated in the variable volume chamber 43 is reduced to
2), and does not act on the brakes 23, 24 of the rear wheels 4.5 as driven wheels.

The displacement position of the piston 42 is adjusted by adjusting the control hydraulic pressure to the control chamber 44. To explain this point in detail, the supply pipe 48 extending from the reservoir 47 is branched into two in the middle, and one branch pipe 48R is connected to the valve 30.
The valve 310 is connected to the control chamber 44, and the other branch pipe 48L is connected to the control chamber 44. A pump 49 and a relief valve 50 are connected to the supply pipe 48, and a supply valve SV3 (SV2) consisting of an electromagnetic on-off valve is connected to the branch pipe 48L (48R). Each control chamber 44 is further connected to the reservoir 47 via a discharge pipe 51R or 51L, and a discharge valve SV4 (SVI) consisting of an electromagnetic on-off valve is connected to the discharge pipe 51L (51R).

During braking (slip control) using this hydraulic pressure control valve 30 (31), the check valve 46 basically prevents the brake pedal 32 from being applied. However, when the brake fluid pressure generated by the fluid pressure control valve 30 (31) is small (
For example, during depressurization), the brake is applied by operating the brake pedal 32. Of course, the hydraulic pressure control valve 30 (
31), when brake fluid pressure for slip control is not generated, the mask cylinder 27 and the brake 21 (22)
Since the brake pedal 27 is in a communicating state, a normal braking action is performed due to the operation of the brake pedal 27.

The opening and closing of each of the valves SV1 to SV4 is controlled by a brake control unit UB, which will be described later. Condition of brake fluid pressure to brake 21.22 and each valve Sv
The operational relationship with SV1 to SV4 is summarized in the following table.

(Hereinafter, blank space) In Figure 1 of the control unit configuration overview, U is the control unit, which can be roughly divided into the brake control unit (UB) described above, as well as the throttle control unit (U) and slip control unit. control unit)
It is composed of the US. The control unit UB controls each valve SVI to SV4 as described above based on the command signal from the control unit US.
Opening/closing control. In addition, 1 throttle control unit) UT is the control unit) U.
Based on the command signal from S, drive control of the throttle actuator 14 is performed.
The control unit US for Nislip control is composed of a digital computer, more specifically a microcomputer. This 1 control unit US includes each sensor (or switch) 61 to 6.
The signal from 8 is input. The sensor 61 detects the opening degree 1 of the throttle valve 13.

The sensor 62 detects whether the clutch 71 is fully engaged.

The sensor 63 detects the gear position of the transmission 8.

Sensors 64 and 65 detect the rotational speed of the left and right front TA2.3 as drive wheels. The sensor 66 detects the rotational speed of the left rear wheel 4 as a driven wheel, that is, the racing speed. The sensor 67 detects the amount of operation of the accelerator 69, that is, the opening degree of the accelerator. The sensor 68 detects the amount of operation of the steering wheel 70, that is, the steering angle. The sensors 64, 65, 66 are each constructed using, for example, a big ag, and the sensors 61, 63, 67, 68 are depicted using, for example, a potentiometer.
2 is constituted by, for example, a switch that operates ON and OFF.

In addition, the control unit) US is basically two PUs,
It is equipped with ROM, RAM, CLOCK, and other input/output interfaces, and also has an A/D or )/A converter depending on the input signal and output signal.
Since these points are the same as those normally used when using a microcomputer, a detailed explanation thereof will be omitted. Note that the maps etc. in the following explanation are those stored in the ROM of the control unit (US).Next, the control contents of the control unit U will be explained in order, but the slip rate S used in the following explanation is , shall be defined by the following equation (1).

WD: Number of revolutions of the driving wheels (2, 3) WL: Number of revolutions of the driven wheels (4) (vehicle speed) The throttle control unit UT feeds the throttle valve 13 (throttle actuator 14) so that the target throttle opening is achieved. /hetsuk control. During this throttle control, when slip control is not performed, the target throttle opening is controlled to correspond 1:1 to the amount of operation of the accelerator 69 operated by the driver, and the accelerator opening at this time is An example of the correspondence between the degree and the throttle opening is shown in FIG. Furthermore, during slip control, the control unit UT performs throttle control so as to achieve the target throttle opening degree Tn calculated by the control unit US, without following the characteristics shown in FIG.

Throttle valve 1 using control unit UT
In the embodiment, the feedback control No. 3 is performed by PI-FD sub-control in order to compensate for fluctuations in the response speed of the engine 6. That is, during slip control of the drive wheels, the opening degree of the throttle valve 13 is sub-controlled by PI-FD so that the current slip rate matches the target slip rate. More specifically, the target throttle opening degree Tn during slip control is calculated by the following equation (2).

Tn = Tnl -5ET -3ET -FP (WDn-WDn-1) -F D (WDn -2X WDn-1+ WDn
-2)... (2) WL: Number of revolutions of driven wheels (4) WD: Number of revolutions of driving wheels (2, 3) KP: Constant of proportionality KI: Constant of integration FP: Constant of proportionality FD = Differential constant SET: As in the target slip ratio (for throttle control) h memory (2), the throttle opening degree Tn is feedback-controlled on the rotational speed of the drive wheels so that it becomes a predetermined target slip ratio SET. In other words, as is clear from equation (1) above, the throttle opening is determined by the target drive wheel rotation speed WE.
T is controlled so that it satisfies the following equation (3).

PI-FD using the control unit UT described above
The sub-control is shown in FIG. 3 as a block diagram, and "S'" shown in FIG. 3 is "operator", and each suffix "n", rn-1" indicates the current Shows the value of each signal at the previous sampling time.

When the brake control slip is 1121, the control unit)
The rotation (slip) of the left and right drive wheels 2.3 using the UB is feedback-controlled so that the left and right wheels independently reach a predetermined target slip rate SBT.In other words, the brake control is set by the following equation (4). Feedback control is performed so that the drive wheel rotational speed WBT becomes the same.

In this embodiment, the target slip rate SBT of the brake is set larger than the target slip rate SET of the engine, as will be described later. In other words, the slip control of this embodiment increases or decreases the engine output to a predetermined SET (WET), and also increases or decreases the engine output to a predetermined SET (WB).
The frequency of use of the brake is reduced by increasing and decreasing the torque by the brake so that the torque becomes T). In this embodiment, feedback control that satisfies the above equation (4) is performed by I-FD control, which has excellent stability. More specifically, the brake operation amount (operation amount of the piston 44 in the valve 30, 31) Bn is calculated by the following equation (5).

Bn=Bn-1 + K I (WLnX -WDn)-
5ET -F P (WDr+ -WDn-1) -F D
(WDn-2X WDn-1+ WDr+-2)...
Φ(5) KI: Integral coefficient KD: Proportional coefficient FD: Derivative coefficient When the above Bn is greater than 0 ("positive"), the brake fluid pressure is increased, and when it is less than 0, it is reduced. This increase/decrease in brake fluid pressure is controlled by the valve 5VI-
This is done by opening and closing 3V4. In addition, the adjustment of the increase/decrease speed of brake fluid pressure is performed using the valve 5VI-3V mentioned above.
This is done by adjusting (duty control) the ratio of the opening/closing time (duty ratio) of No. 4, and the duty control is proportional to the absolute value of Bn determined by the above equation (5).

The knee FD control by the control unit UB described above is shown in FIG. 4 as a block diagram.
"S'" shown in the figure is an "operator".

In this embodiment, the brake operation amount Bn is corrected according to the degree of turning of the vehicle, and the larger the degree of turning, the smaller the brake operation amount Bn. is designed to slow down the Further, in this embodiment, the degree of turning is detected by the steering angle of the steering wheel.

Overview of Slip Control An overall overview of the slip control by the control unit U will be explained with reference to FIG. The meanings of the symbols and numerical values shown in FIG. 5 are as follows.

S/C Nislip control area E/G: Slip control by engine B/R Slip control by Nibrake F/B: Feedback control 0/R: Open loop control R/Y: Recovery control B/A: Backup control A/S: Buffer control S = 0, 2 Slip rate at the start of Nislip control (SS
) S=0.17: Target slip rate by brake (S ET
) S = 0.09 Slip rate when stopping slip control by brake (S 5C) s = o, os: Target slip rate by engine (S
ET) s = o, oi ~ 0.02: Slip rate in the range where buffer control is performed S = 0.01 or less: Slip rate in the range where backup control is performed The following is an indication based on data obtained from driving.6
Then, S=o, oi and 0.02 to perform buffer control A/S
, and the slip rates s=o and o9 at the time of stopping the slip control by the brake are respectively unchanged in the embodiment.

On the other hand, the target slip rate SBT by the brake, the target slip rate SET by the engine, and the slip rate SS at the start of slip control are changed depending on the road surface condition, etc., and FIG. , l 7
J, ro, 06J or rO, 2J is shown.

The slip rate S=0.2 at the start of slip control is
The slip rate at the time of maximum grip force obtained when using spiked tires is used (see solid line in Figure 13).
. In this way, the slip rate at the start of slip control is set to 0.2.
The reason for this is that the actual slippage rate when this maximum grip force is obtained can be calculated, and depending on the slippage rate when this maximum grip force is generated, the engine and brake Target slip 1sET,
SBT is corrected. The solid line in FIG. 13 shows how the grip force and lateral force (expressed as the coefficient of friction against the road surface) of spiked tires change in relation to the slip rate. Moreover, the broken line in FIG. 13 shows the relationship between grip force and lateral force when using normal tires.

(Hereinafter, blank space) Based on the above, FIG. 5 will be explained as time goes on.

(2) to-t1 Since the slip rate S does not exceed S=0.2, which is the condition for starting slip control, slip control is not performed. That is, when the slip of the driving wheels is small, acceleration performance can be improved by not controlling the slip (driving using a large grip force). Of course, at this time,
The characteristics of the throttle opening with respect to the accelerator opening are the 12th
It is uniformly determined as shown in the figure.

(t1 to t2) Slip control is started and the slip rate is equal to or higher than the brake-based slip control stop point (S=0.09). At this time, since the slip rate is relatively large, slip control is performed by reducing the torque generated by the engine and braking by the brake. In addition, since the target slip rate of the brake (S = 0.17) is larger than the target slip rate of the engine (S = 0.06), the brake is pressurized when there is a large slip (Sho, 17). However, when there is a small slip (S<0, 17), the brake is not pressurized and the slip is controlled only by the engine so that the slip settles.

(2) t2~1+ (Recovery Control) The throttle valve 13 is maintained at a predetermined opening degree for a predetermined time (for example, 170 m5ec) after the slip converges (S<0.2) (oven loop control). At this time,
S=O/2 (mu2) fP? Maximum acceleration at point G WAX
is determined, and the maximum JL (maximum grip force of the driving wheels) of the road surface is estimated from this G MAX. Then, the throttle valve 13 is held for a predetermined period of time as described above so as to generate the maximum grip force for the driving wheels. This control is
Since the slip convergence occurs rapidly, the feed control control cannot respond in time, and this is done to prevent the vehicle body acceleration G from dropping immediately after the slip convergence. Therefore, when the convergence of slip is predicted (S=0.2 or lower), a predetermined torque is secured in advance as described above, and
Acceleration is improved.

The optimal throttle opening TVo to achieve the torque applied to the drive wheels that can generate the maximum grip force mentioned above is:
Although it can be determined theoretically from the torque curve of the engine 6 and the gear ratio, in the embodiment, it is determined based on a map as shown in Fig. i15, for example. This map was created using an experimental method, and G MAX is 0.15.
When it is less than 0.4 and more than 0.4, it is set to a predetermined constant value in consideration of the measurement error of G MAX. It should be noted that the map shown in FIG. 12 is based on the assumption that the vehicle is at a certain gear position (for example, 1st gear), and the optimum throttle opening Tvo is corrected at other gear positions.

(4) t4 to t7 (backup control, buffer control) In order to deal with the situation when the full rate S decreases abnormally,
Backup control is performed (open loop control).

That is, when S<0,01, the feedback control is stopped and the throttle valve 13 is opened in stages. When the slip rate is between 0.01 and 0.02, buffer control is performed to smoothly transition to the next feedback control (14 to t5 and t6 to t7). This backup control is performed when neither feedback control nor recovery control can cope with the problem. Of course, this backup control is assumed to have a sufficiently faster response speed than feedback control.

In this embodiment, the rate of increase in the throttle opening in this backup control is set to 0% with respect to the previous throttle opening at every 14 m5 ec of sampling time of the throttle opening.
．． It is assumed that an additional amount of 5% opening is added.
In addition, in the above-mentioned buffer control, as shown in FIG. 16, the throttle opening degree T2 obtained by the feedback control calculation and the throttle opening degree T obtained by the backup control operation are controlled by the current slip rate So. The throttle opening degree To is obtained by proportional distribution.

I > t7 to t8 By performing the control from t7 to t7, there is a smooth transition to slip control using only the engine.

(?) Since the accelerator 69 is fully closed by the driver after t a, slip control is stopped. At this time, the throttle valve 13
Even if the opening degree is left to the driver's will, there is no risk of slipping again because the torque has been sufficiently reduced. In addition, in the embodiment, the slip control is canceled not only when the accelerator is fully closed, but also when the target throttle opening due to the slip control becomes smaller than the driver's opening.

Details of slip control a (flow chart) Next, Fig. 6~
The details of the slip control will be explained with reference to the flowchart in FIG. It also controls the stack. In addition, in the following explanation, P
indicates a step.

FIG. 6 (Main) After the system is initialized at the PI, it is determined at P2 whether or not the system is currently stuck (such as stuck in mud or the like and unable to move). This determination is made by checking whether a stack flag, which will be described later, is set. When the determination in P2 is NO, it is determined in P3 whether or not the accelerator 69 is fully closed. When the determination in P3 is NO, it is determined in P4 whether or not the current throttle opening is greater than the accelerator opening. If the determination in P4 is No, it is determined in P5 whether or not slip control is currently being performed. This determination is made by checking whether the slip control flag is set. When the determination in P5 is No, it is determined in P6 whether or not a slip that causes slip ffjlV4 has occurred. This determination is
This is done by checking whether slip flags for the left and right front wheels 2.3, which will be described later, are set.

When it is determined NO in this P6, move to P7,
Sleeve 2 control is canceled (normal driving).

If YES is determined in P6, the process moves to P8, where the slip control flag is set.

Subsequently, in P9, the initial value of the target slip rate SET for the engine (throttle) (0.06 in the example) is set, and in PIO, the initial value of the target slip rate for the brake: $SET (0 in the example) is set. .17) is set. After this, brake control with PLL and PI3 are performed for slip control, as will be described later.
engine control is performed. Note that the setting of the initial value to 1 at P9 and PIO is performed from the same viewpoint as P76, which will be described later, based on the maximum acceleration G WAX obtained in the previous slip control.

When the slip control flag determines YES in P5, the process moves to the above-mentioned FIL and the slip control is continued.

When the determination in P4 is YES, it means that slip control is no longer necessary, and the process moves to PI3. This PI
3, the slip control flag is reset. Then,
Engine control is stopped at PI3, and brake control is performed at PI3. It should be noted that this brake control in PI3 is performed as a countermeasure against a stuck situation.

If YES is determined at P3, the brake is released at PI3, and then the processes from P14 onwards are performed.

When the determination in P2 is YES, the processes from P15 onward are performed.

7 and 8 The flowchart in FIG. 7 interrupts the main flowchart in FIG. 6, for example, every 14 m5ec.

First, in P21, each signal from each sensor 61 to 68 is input for data processing. Next, after slip detection processing, which will be described later, is performed in P22, throttle control is performed in P23.

The throttle control at P23 is performed according to the flowchart shown in FIG. First, in P24, it is determined whether the slip control flag is set, that is, whether slip control is currently being performed. When YES in P24, the control of the throttle valve 13 is selected for slip control, that is, control that does not follow the characteristics shown in the ilZ diagram and achieves a predetermined target slip -J SET. If the determination in P24 is NO, the opening/closing control of the throttle valve 13 is selected to be left to the driver's will (according to the characteristics shown in FIG. 12) in P26. After P25 and P26, 1υ control is performed in P27 to achieve the target throttle opening (
control according to P68, P2O, and P71, which will be described later, or control according to the characteristics shown in FIG. 12).

FIG. 9 (Slip Detection Process) The flowchart in FIG. 9 corresponds to P22 in FIG. 7. This flowchart is for detecting whether a slip that is subject to slip control has occurred and whether or not the vehicle is stuck.

First, in P31, it is determined whether the clutch 7 is completely connected. If YES is determined in P31, it is assumed that the stack is not in progress, and the stack flag is reset in P32. Then P3
3, the current vehicle speed is low, for example 6.3 km.
It is determined whether or not the value is smaller than /h.

When the determination in P33 is No, a correction value α for slip determination is calculated in P34 according to the steering angle of the steering wheel (see FIG. 14). After this, in P35, the slippage rate of the left front wheel 2 as the left driving wheel is set to a predetermined value! & Market value 0.2 It is determined whether the value is greater than the value (0,2+α) obtained by adding α in P34 above. With this P35 discrimination,
If YES, it is assumed that the left front wheel 2 is in a slip state and its slip flag is set. On the other hand, N at P35
When the determination is O, the slip flag for the left front wheel 2 is reset. Note that the correction value α is set in consideration of the rotational difference between the inner and outer wheels (especially the rotational difference between the driving wheel and the driven wheel) during turning.

After P36 or P37, P38, P3O, P2O
In P35 and P3, the slip flag for the right front wheel 3 as the right driving wheel is set or reset.
6. It is performed in the same manner as P37.

If YES is determined in P33, the vehicle speed is low, and there will be a large error in calculating the slip rate using the vehicle speed, that is, based on equation (1). It is intended to be detected only by That is, at P41, the rotation speed of the left front wheel 2 is
It is determined whether the rotational speed is greater than the rotational speed equivalent to a vehicle speed of 10 km/h. When it is determined as YES in this P41, P
At 42, the slip flag for the left front wheel 2 is set. Conversely, when the determination is No at P41, the slip flag for the left front wheel 2 is reset at P43.

After P42 and P43, the slip flag for the right front wheel 3 is set or reset in P44, P45, and P46 in the same manner as in P41 to P43 described above.

When the determination in P31 is NO, there is a possibility that the vehicle is stuck (when the driver is stuck, the driver tries to escape from the mud etc. while using the clutch partially).

In this case, the process moves to P51, and it is determined whether the average value of the rotational speed of the left and right front wheels 2 and 3 as driving wheels is small (for example, whether it is 2 km/h or less in terms of vehicle speed). ). If P51 is determined as NO, P
At step 52, it is determined whether or not the stack is currently under control.
11. If P52 is determined as NO, P53
At , it is determined whether the rotational speed of the right 'ff1 wheel 3 is greater than the rotational speed of the left front wheel 2. When it is determined YES in P53, it is determined whether the rotation speed of the right front wheel 3 is greater than 1.5 times the rotation speed of the left front wheel 2.

If YES is determined in P54, a stack flag is set in P56. On the other hand, if the determination in P54 is No, it is assumed that the stack is not in progress, and the above-mentioned P3
2 and subsequent processes are performed.

Further, when the determination in P53 is NO, in P55, the rotation speed of the left front wheel 2 is 1.5 times the rotation speed of the right front wheel 3.
It is determined whether or not it is greater than five times. Y with this P55
If the answer is ES, the process goes to P56, and if the answer is No, the process goes to P32.

After P56, the vehicle speed is 6.3km/h at P57.
It is determined whether or not it is larger than . YES on this P57
When this happens, the target rotation speed of the front wheels 2.3 is set to be 1.25 times the rotation of the driven wheels, which indicates the vehicle speed.
(equivalent to a slip ratio of 0.2). Also, if NO in P57, the target rotation speed of the front wheel 2.3 is set to 10k in P59.
It is uniformly set to m/h. When YES at P51, the brake is slowly released at P2O.

Figure 1O (engine control'a) The flowchart shown in Figure 10 is based on P12 in Figure 6.
Compatible.

At P61, it is determined whether the slip has transitioned to a convergence state (whether it has passed time t2 in FIG. 5). When the answer is No in P61, it is determined in P62 whether the slip rate S of the left front wheel 2 is greater than 0.2. N at P62.

In this case, it is determined in P63 whether the slip rate S of the right front wheel 3 is greater than 0°2. If NO in P63, it is determined in P64 whether only one of the left and right front wheels 2.3 is under brake control, that is, whether the vehicle is traveling on a split road. When YES in P84, the current slip rate is calculated in P65 using the drive wheel with the lower slip rate among the left and right front wheels 2.3 as a substrate (select low). On the other hand, when P64 is No, the current slip ratio is calculated according to the drive wheel with the larger slip ratio among the left and right front wheels 2.3 (select high). In addition, N at P62 and P63.

In this case, the process also moves to P66.

The selection high at P66 allows the use of the brake to be further avoided by calculating the current slip rate in order to suppress the slip of the slippery drive wheel. On the other hand, the select low in P65 above is effective when driving on a split road where the friction coefficients of the road surface that the left and right drive wheels touch are different, while suppressing the slip of the drive wheel that is more likely to slip by the brake. This makes it possible to drive by taking advantage of the grip of the drive wheel on the weaker side.

In addition, in the case of this select low, in order to avoid overusing the brakes, it is advisable to take backup measures such as limiting the select low to a certain period of time, or stopping the select low when the brakes overheat.

After P65 and P66, it is determined in P67 whether the current slip ratio S is greater than 0.02. When YES in P67, the throttle valve 13 is feedback-controlled for slip control in P68. Of course, at this time, throttle/help 13
The target throttle opening (Tn) is P65, P66-1
1' or changed in P76, which will be described later, is set to realize the target slip rate SET.

If No in P67, it is determined in P69 whether the current slip ratio S is greater than 0.01. If YES in P69, the buffer control described above is performed in P2O. Also, if P69 is NO, P71
In this step, the above-mentioned /head-up control is performed.

Furthermore, when YES in P61, it is assumed that the large slip of the drive wheels is converging, and the process moves to P72, and after shifting to the direction of slip convergence, a predetermined period of time (time for performing recovery control, as described above in the embodiment) 170m5 as shown
ec) It is determined whether or not the time has elapsed. If No in P72, the processes from P73 onwards are performed to perform recovery control. That is, first, at P73, the maximum acceleration G MAX of the automobile 1 is measured (at time t2 in FIG. 5).

Next, in P74, the optimum throttle opening degree Tv□ is set so that this G MAX can be obtained (see FIG. 15). Further, at PI5, the optimum throttle opening degree Tv□ at P74 is corrected according to the current gear position of the transmission 8. That is, since the torque applied to the drive wheels differs depending on the gear position, the optimum throttle opening degree Tv□ for a certain standard gear position is set in P74,
PI5 is designed to correct this difference in gear position.

After this, in P76, the friction coefficient of the road surface is estimated from G WAX in P73, and the target slip rate S for subsequent slip control by the engine (throttle) and brake is determined.
Change both ET and SBT. Note that changing the target completion rates SET and SBT as shown in the following will be described later.

If YES in P72, this means that the recovery control has ended, and the processes from P62 onwards are performed.

The target slip ratios SET and 3BT between the engine and the brake that are changed in P76 are changed as shown in FIG. 17, for example, based on the maximum acceleration G WAX measured in P73. As is clear from this i17 figure,
As a general rule, the larger the maximum acceleration GWAX is, the larger the target slip rate SET and SBT should be. Limit values are set for each of the target slip rates SET and SET.

FIG. 11 (Brake Control) The flowchart shown in FIG. 11 corresponds to the pH and PI3 in FIG. 6.

First, in P81, it is determined whether or not the stack is currently in progress. If NO at P81, at P82,
The brake pressure increase/decrease speed limit value (BLM) is set to a value that corresponds to the vehicle speed (the higher the vehicle speed, the greater the value) based on the following formula.

BLM=f (V) Here, ■: When YES at vehicle speed P81, in P83, the above limit ([BLM is set as a constant value smaller than that in P82. Note that the processing in P82.83 , Bn as calculated by the above formula (5), the rate of increase/decrease in brake fluid pressure is too fast, causing vibrations, etc., and it is difficult to obtain braking according to the vehicle speed. In addition, in P83, it is particularly undesirable for the braking force applied to the driving wheels to change suddenly in order to escape from the stuck state, so a small constant value is set as the limit value.

After P82 or P83, it is determined in P84 whether the slip rate S is larger than 0, 09, which is the brake control stop point. When YES in P84, the operating amount B of the right front wheel brake 22 is determined in P85.
n is calculated (corresponding to Bn in the I-FD control in FIG. 4).

Then, in the next P86, the brake operation amount Bn obtained in the above P85 is corrected according to the steering angle. That is, as shown in Fig. .

After this, in P87, it is determined whether the above-mentioned Bn is larger than "0". This determination is performed to determine whether or not the brake pressure is in the pressure increasing direction, assuming that the pressure increasing direction of the brake is positive and the pressure decreasing direction is negative. When YES in P87, it is determined in P88 whether or not it is Bn) BLM. P88
If YES, the corrected brake operation amount Bn exceeds the limit (11iBLM), and after setting Bn to the limit value BLM (P89), at P2O,
The pressure of the right brake 22 is increased. Also, No on P88
In this case, the pressure at P2O is increased using the Bn value corrected at P86.

Through this series of steps, the brake speed is changed according to the steering angle (see FIG. 19).

If NO in P87, Bn is "negative" or "0".
”, so after converting Bn into an absolute value in P91, P92
- 94 processes are performed. These P92 to P94 are when the pressure of the right brake 22 is reduced, and the above-mentioned P88, P89,
It supports P2O processing.

After P2O and P94, the process moves to P95, and pressure increase or decrease processing is performed for the left brake 21 in the same way as for the right brake 22 (process corresponding to P84 to P94).

On the other hand, if the answer is No in P84, it is time to cancel the brake control, so the brake is released in P96.

In addition, between P85 and P86, the actual rotation speed and target rotation speed (actual slip rate and target slip rate) of the drive wheels
If the difference between Become.

(Hereinafter, blank spaces) Although the embodiments have been described above, the present invention is not limited thereto, and includes, for example, the following cases.

■ As a means of changing the brake speed, the brake operation amount B
We decided to correct n by the steering wheel angle (m1+
(P86 in the figure), even if the control gain of each operation in brake control, for example the KI value (formula (5)), is changed according to the steering angle (when the steering angle is large, the KI value is small). Good (P85 in Figure 11) or 11th
In the figure, by changing the limit value BLM according to the steering angle at P82, the brake speed may be regulated by the limit value BLM according to the degree of turning of the vehicle.

(The brake pressure increase speed may be regulated by providing a separate brake pressure sensor and directly detecting the brake pressure with this brake pressure sensor.

For example, in the flowchart shown in FIG.
Alternatively, a step may be provided before P94 to maintain the brake pressure when the value detected by the brake pressure sensor is a predetermined value.

(2) Furthermore, instead of the brake speed, the absolute value of the brake pressure, that is, the absolute value of the control, may be changed.

■For detecting the degree of turning of the vehicle, lateral G that forces the vehicle
Alternatively, it may be performed by measuring the yaw of the vehicle.

(1) If the output torque of the engine is used to adjust the torque applied to the drive wheels, it is preferable to change and control the factors that most affect the output generated by the engine. In other words, it is preferable to adjust the generated torque by so-called load control, and in the case of an automatic engine (for example, a gasoline engine), by adjusting the mixture amount, and in the case of a diesel engine, by adjusting the amount of fuel injection. However, it is not limited to this load control.
This may be done by adjusting the ignition timing in an Otto type engine, or by adjusting the fuel injection timing in a diesel engine. Furthermore, in engines that require supercharging, this may be done by adjusting the supercharging pressure. Of course, the power source is not limited to an internal combustion engine, but may also be an electric motor, and in this case, the generated torque may be adjusted by adjusting the power supplied to the motor. Further, the adjustment may be performed not only by adjusting the engine but also by adjusting the connection state of the clutch 7 and the gear ratio of the transmission 8. In this case, especially the continuously variable transmission fi (C
VT) is preferred.

6) In the automobile 1, the front wheels 2.3 are not limited to driving wheels, but the rear wheels 4.5 may be driving wheels, or even if all four wheels are driving wheels. good.

(P) In order to detect the slipping state of the driving wheels, it is possible to directly detect the rotational speed of the driving wheels as in the embodiment, but in addition, this slipping state can be detected depending on the state of the vehicle. prediction,
In other words, it may be detected indirectly. Such vehicle conditions include, for example, an increase in the generated torque or rotational speed of the power source, a change in the degree of accelerator opening, a change in the rotation of the drive shaft, the steering condition (cornering), and the floating condition of the vehicle body (acceleration). ,product! ! Possible factors include quantity. In addition, by automatically detecting or manually inputting atmospheric temperature levels, rain, snow, icy roads, etc., the prediction of the slipping state of the drive wheels can be made even more appropriate. You can also do it.

(Effects of the Invention) As is clear from the above description, the present invention adjusts the torque applied to the drive wheels according to the turning state of the vehicle, thereby improving safety while turning and causing slippage while traveling straight. It is possible to improve convergence.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall system diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing an example of a brake fluid pressure control circuit. FIG. 3 is a block diagram when performing feedback control of the throttle valve. Figure 4 is a block diagram of brake feedback control. FIG. 5 is a graph schematically showing a control example of the present invention. 6 to 11 are flowcharts showing control examples of the present invention. FIG. 12 is a graph showing the characteristics of throttle opening relative to accelerator opening when slip control is not performed. The 7pJls diagram shows the relationship between the drive wheel grip force and lateral force.
A graph showing the relationship between the slip rate and the coefficient of friction against the road surface. FIG. 14 is a graph showing correction values when correcting the slip rate at the start of slip control according to the steering angle of the steering wheel. FIG. 15 is a graph showing the optimum throttle opening corresponding to the maximum acceleration during beam recovery control. FIG. 16 is a graph showing the relationship between the fullness rate and the throttle opening when performing buffer control. FIG. 17 is a graph showing an example of a map used when determining the target slip rate. FIG. 18 is a graph showing the relationship between the correction coefficient of the brake operation amount and the steering angle. FIG. 19 is a graph corresponding to FIG. 5, showing an example of brake control according to vehicle speed. FIG. 20 is an overall configuration diagram of the present invention. 1: Automobile 2.3: Front wheel (driving wheel) 4.5: Rear wheel (driven wheel) 6: Engine (power source) 7: Clutch 8: Transmission 13: Throttle valve 14: Throttle actuator 21-24 Brake 27: Master cylinder 30.31: Hydraulic pressure control valve 32 Brake pedal 61: Sensor (throttle opening) 64.65: Sensor (driving wheel rotation speed 9 66: Sensor (driven wheel rotation speed) 67: Sensor (accelerator opening) 68: Sensor (handle steering angle) SVI to SV4: Electromagnetic opening/closing valve U: Control unit Fig. 2 Fig. 12 Handle B Fig. 13 S (ungrid) Fig. 15 MAX Fig. 16 Fig. 17 MAX Figure 18 Figure 20 Procedural amendment document July 21, 1986

Claims (1)

[Claims] (1) A slip control device for an automobile that prevents excessive slip of the drive wheels relative to the road surface by controlling the torque applied to the drive wheels, comprising: a turning detection means for detecting a turning state of the vehicle; control adjustment means that receives a signal from the turning detection means and reduces the control speed or control amount in the direction of reducing the applied torque when the vehicle is in a turning state compared to when the vehicle is in a straight-ahead state; An automobile slip control device characterized by: