JP3207453B2 - Vehicle slip control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slip control device for a vehicle, which controls a torque applied to the drive wheels to prevent the drive wheels from slipping significantly during acceleration of the vehicle.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 1-106762, in order to prevent a decrease in acceleration performance due to a large slip of a driving wheel during acceleration of a vehicle or the like, a slip value of the driving wheel is reduced. When the slip value is equal to or greater than a predetermined reference value, the slip control device reduces the output of the engine and applies a braking force to the drive wheels to reduce the drive torque of the drive wheels. It has been done to recover the grip force.

[0003] The slip control device having the above-described configuration calculates the slip value of each drive wheel in accordance with the difference between the vehicle speed obtained by averaging the rotational speeds of the left and right driven wheels and the rotational speed of the left and right drive wheels. In addition to the calculation, it is determined whether or not the vehicle is traveling on a rough road according to the unevenness of the traveling road or the like, and when it is confirmed that the vehicle is traveling on a rough road, the vehicle is determined according to the slip value. The control variables are smoothed by a filter to reduce noise generated when the wheels vibrate according to the unevenness of the traveling road, and to prevent malfunction of the control means caused by the noise. Have been.

[0004]

When the slip value of the drive wheel is calculated based on the vehicle speed obtained by averaging the rotational speeds of the left and right driven wheels as described above, Although the left-right deviation of the rotational speed of the driven wheels caused by the unevenness of the traveling road can be eliminated to some extent, the problem that the detection error corresponding to the difference between the inner and outer wheels generated when the vehicle turns cannot be avoided. There is.

In the case where the control variable obtained according to the slip value of the drive wheel is smoothed by a filter as described above, the peak position of the control variable is shifted and the response delay of the control tends to occur. Therefore, an oscillation phenomenon occurs due to the response delay, and the slip value of the drive wheel may be largely changed by executing the slip control.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended to reduce a slip value detection error corresponding to a difference between inner and outer wheels generated at the time of turning of a vehicle, an oscillation phenomenon caused by a control response delay, and the like. It is an object of the present invention to provide a vehicle slip control device that can prevent generation of noise due to vibration of wheels when traveling on a rough road without causing such a problem.

[0007]

Means for Solving the Problems The invention according to claim 1,
As shown in FIG. 1, drive wheel speed detection means 51L and 51R for detecting the rotation speed of the left and right drive wheels, and driven wheel speed detection means 52L and 52R for detecting the rotation speed of the left and right driven wheels.
When it is confirmed that the drive wheels have slipped in accordance with the detection signals output from these detection means 51L, 51R, 52L, 52R, the output of the engine or the braking force is controlled to reduce the slip value of the drive wheels. A slip control device for a vehicle that controls so as to converge to a target value, wherein a rough road determination unit 53 that determines whether a running road is a rough road and a vehicle that is running straight are determined. The straight traveling state determination means 54 and the drive wheel speed detection means 51L, 51
The slip control of the left driving wheel is executed based on the rotation speed of the left driving wheel and the rotation speed of the left driven wheel detected by the R and the driven wheel speed detecting means 52L and 52R,
First control unit 55 that executes slip control of the right drive wheel based on the rotation speed of the right drive wheel and the rotation speed of the right driven wheel.
And the rough road determination means 53 and the straight traveling state detection means 54
When it is confirmed that the vehicle is traveling straight on a rough road, the slip control of each drive wheel is executed based on the rotation speeds of the left and right drive wheels and the average rotation speed of the left and right driven wheels. A control unit 56 is provided.

[0008]

According to the first aspect of the present invention, when the vehicle is traveling on a good road or turning, the slip values of the drive wheels are obtained independently for left and right. When the vehicle is traveling straight on a rough road, the slip values of the left and right drive wheels are determined based on a common value obtained by averaging the left and right driven wheel speeds. Then, the slip control of the drive wheels is executed based on this value.

[0009]

EXAMPLES Overview of vehicle configuration diagram 2 shows a system diagram of a hydraulic circuit for brake control of the engine and the wheels of the vehicle which the vehicle slip control system is applied according to the present invention. This vehicle has left and right front wheels 1L and 1R serving as driven wheels and left and right rear wheels 2L and 1L serving as driving wheels.
2R, so that the driving force of the engine 3 is transmitted to the rear wheels 2L, 2R via the automatic transmission 4, the propeller shaft 5, the differential 6, and the left and right axles 7L, 7R.

[0010] configuration the automatic transmission 4 of the automatic transmission, a torque converter as known 8
And a multi-stage transmission gear mechanism 9, and a plurality of solenoids 10 incorporated in a hydraulic circuit of the multi-stage transmission gear mechanism 9.
Is changed by changing the combination of the excitation and the demagnetization. Further, the torque converter 8 has a hydraulically operated lock-up clutch 11, and engagement and release are performed by switching between excitation and demagnetization of a solenoid 12 incorporated in the hydraulic circuit. ing.

The solenoids 10 and 12 are controlled in accordance with a control signal output from a shift control unit (not shown). The control unit for this shift control is:
A control signal for executing a predetermined shift control and lock-up control based on a shift characteristic and a lock-up characteristic set in a known manner and a detection signal output from a throttle opening sensor and a vehicle speed sensor is described above. The output is provided to the solenoids 10 and 12.

Structure of Brake Fluid Pressure Adjusting Mechanism The front wheels 1L and 1R and the rear wheels 2L and 2R are
Brakes 15a to 15d are provided, respectively, and calipers 16a to 16d of the brakes 15a to 15d are connected to brake pressure supply pipes 17a to 17d.
The depressing force of the brake pedal 18 is boosted by a hydraulic booster 19 and transmitted to the master cylinder 20. The caliper of the left front wheel 1L passes from the first discharge port 21a of the master cylinder 20 via the pipe 17a. The brake fluid pressure is supplied to the caliper 16b of the right front wheel 1R from the second discharge port 21b of the master cylinder 20 via the pipe 17b.

The booster 19 is supplied with hydraulic pressure from a pump 23 via a pipe 22, and the excess hydraulic pressure is returned to a reserve tank 25 via a return pipe 24. Branch pipe 2 branched from the pipe 22
2a is connected to a junction G with a pipe 27 described later, and the branch pipe 22a is provided with an electromagnetic on-off valve 26. Further, the boosting hydraulic pressure generated in the booster 19 is supplied to the junction G via a pipe 27, and the pipe 27 is provided with an electromagnetic on-off valve 28. I have. The pipe 27 is provided with a one-way valve 29 in parallel with the electromagnetic on-off valve 28 for allowing the flow of the brake oil to the junction G side and preventing the flow in the opposite direction.

The junction G is connected to brake pipes 17c and 17d for the right and left rear wheels 2L and 2R.
7c, 17d are provided with electromagnetic on-off valves 29A, 30A. A relief passage 31L having an electromagnetic on-off valve 29B is provided downstream of the installation part of the electromagnetic on-off valve 29A, and an electromagnetic on-off valve is provided downstream of the installation part of the electromagnetic on-off valve 30A. A relief passage 31R having 30B is provided.

Each of the on-off valves 26, 28, 29A, 29
B, 30A, 30B constitute a braking force control means 32 for the rear wheels 2L, 2R, and a control unit UTR for slip control.
Is controlled by When the slip control is not performed, as shown, the on-off valve 26 is closed, the on-off valve 28 is opened, and the on-off valves 29A and 30A are open. Thus, when the brake pedal 18 is depressed, the boosted hydraulic pressure from the hydraulic booster 19 is supplied to the rear wheel brakes 15c and 15d via the pipe 27 as brake hydraulic pressure. Further, the brake fluid pressure is supplied from the master cylinder 20 to the brakes 15a, 15b for the front wheels 1L, 1R.

When the slip control of the rear wheels 2L and 2R is performed, the on-off valve 28 is closed and the on-off valve 26 is opened according to a control signal from the control unit UTR. And, the on-off valves 29A, 29B and 30
By controlling the duty of each of the brake valves A and 30B, the brake fluid pressure is maintained, and the pressure is increased and reduced. That is, when the on-off valve 26 is open,
When each of the on-off valves 29A, 29B, 30A, 30B is closed, the brake fluid pressure is maintained. Also, the on-off valve 29
A, 30A are open and the brake fluid pressure is increased when the on-off valves 29B, 30B are closed.
When A and 30A are closed and on-off valves 29B and 30B are open, the brake fluid pressure is reduced. And branch pipe 2
The brake fluid pressure that has passed through 2a does not act as a reaction force of the brake pedal 18 due to the bypass action of the one-way valve 29.

When the brake pedal 18 is depressed in a state where the slip control is being performed by the braking force control means 32, the brake fluid pressure from the booster 19 is applied to the one-way valve 29 in accordance with the depression. The brake is supplied to the rear wheel brakes 15c and 15d via the rear wheels.

Configuration of Engine Generated Torque Adjusting Mechanism The above-mentioned slip control unit UTR controls the rear wheels 2L, 2R as described above in order to reduce the torque applied to the rear wheels 2L, 2R when a slip occurs. , The braking force control is executed, and the output control for reducing the driving torque of the engine 3 is executed. This output control is
The adjustment is performed by a sub-throttle opening adjustment mechanism 34 provided in the intake passage 33 of the engine 3. The sub-throttle opening adjustment mechanism 34 includes a sub-throttle valve 37 disposed upstream of a main throttle valve 36 that is opened and closed by an accelerator pedal 35, and a sub-throttle valve 3
7 for driving the actuator 7. When a slip occurs, the output of the engine 3 is controlled by opening and closing the sub-throttle valve 37 in accordance with a control signal output from the control unit UTR to the actuator 38.

Configuration of Control Unit for Slip Control The control unit UTR for slip control includes wheel speed sensors 39a to 39d for detecting the rotation speed of each wheel 1L, 1R, 2L, 2R, and opening of the main throttle valve 36. The throttle valve sensor 40 for detecting the degree, the vehicle speed sensor 41 for detecting the vehicle speed, the sub-throttle valve sensor 42 for detecting the degree of opening of the sub-throttle valve 37, the steering angle sensor 43 for detecting the steering angle of the steering wheel, and the above-mentioned running mode etc. A switch 44 used for setting and a brake sensor 4 for detecting that the brake pedal 18 is depressed
5 is input.

According to the contents of the slip control and the output signals, the control unit UTR
It is determined whether or not the vehicle is traveling on a rough road such as an uneven road, and whether or not the steering angle of the steering wheel is equal to or less than a predetermined value. Then, rear wheel 2L, 2R
, And the slip control including the braking force control of the rear wheels 2L and 2R and the output control of the engine 3 is executed according to the calculation result as shown in FIG. In FIG. 3, SET indicates a reference value of a slip value as a reference for determining whether or not to start the slip control of the rear wheels 2L, 2R. When the vehicle accelerates, the rear wheels 2
In the region up to the point A at which the slip values of L and 2R increase beyond the reference value SET, the sub-throttle valve 37
Is maintained in the maximum open state, and the opening degree Tn of the intake passage 33 is set according to the opening degree of the main throttle valve 36. That is, the opening degree TH of the main throttle valve 36, which is opened / closed in accordance with the depression amount of the accelerator pedal 35,
The opening degree Tn of the intake passage 33 is set according to B, and the output control of the engine 3 is executed.

When the slip value of the rear wheels 2L and 2R exceeds the reference value SET when the slip speed exceeds the reference value SET, the actuator 38 is actuated and the opening of the sub-throttle valve 37 is reduced. Feedford control is performed so as to decrease by the initial set value SM set according to the traveling state. As a result, the opening of the sub-throttle valve 37 becomes smaller than the opening of the main throttle valve 36, and the opening Tn of the intake passage 33 is set according to the opening of the sub-throttle valve 37. Then, rear wheel 2
By performing feedback control of the opening degree TH · M of the sub-throttle valve 37 in accordance with the slip state of the left and right wheels 2 and 2R, the slip values of the rear wheels 2L and 2R converge to the slip control target value including the reference value SET. The output control of the engine 3 is executed.

At the time B when the slip value of the rear wheels 2L and 2R further increases from the start time A of the slip control and exceeds a braking force control target value SBT described later, the brakes 15c of the rear wheels 2L and 2R are provided. , 15d, until the slip value of the rear wheels 2L, 2R becomes equal to or less than the target value SBT, until the rear wheel 2
Feedback control is performed on the L and 2R braking forces.

Details of Slip Control Next, details of the slip control by the control unit UTR will be described with reference to a flowchart shown in FIG. When the control operation starts, first, in step S1
Here, each data is input based on signals from each sensor and switch. Next, in step S2, calculation control for calculating the slip value S of the rear wheels 2L and 2R, which are drive wheels, is executed.

Next, in step S3, it is determined whether or not the accelerator is in a fully closed state. When it is confirmed that the accelerator is not in the fully closed state but in a predetermined acceleration state, in step S4, it is determined whether or not the slip flag SF is 1, that is, whether or not the slip control is currently being executed. Is determined. As a result of this determination, when it is confirmed that the slip control is not being executed, in step S5, a reference value SET for determining whether to start the slip control is set.

That is, as shown by the solid line in FIG. 5, the basic slip value STAO corresponding to the current running state is obtained from the map of the basic slip value STAO for engine output control stored using the maximum road surface friction coefficient μmax as a parameter.
Read the value of. A map of the gain coefficient VG using the vehicle speed as a parameter shown in FIG. 6, a map of a gain coefficient ACPG using the accelerator opening as a parameter shown in FIG. 7, and a map and a diagram of the gain coefficient STRG using the steering angle as a parameter shown in FIG. 9 is read from the table of the gain coefficients MODEG corresponding to the driving mode selected in response to the driver's operation of the switch shown in FIG. 9, and these values are multiplied by the basic slip value STAO to start the slip control. Is obtained.

Next, in step S6, the rear wheels 2L, 2L
It is determined whether or not the slip value S of R is larger than the reference value SET. If YES is determined in the step S6, the slip flag SF is set to 1 in a step S7. Then, in a step S8, the output control of the engine 3 is executed, and the step S9 is executed.
, The braking force control of the rear wheels 2L and 2R is executed.

If YES is determined in step S4, and it is confirmed that the slip control is already being executed, the flow directly proceeds to step S8 to continue the slip control. In step S3, it is determined that the accelerator is in the fully closed state, or in step S6, it is determined that the slip value S of the rear wheels 2L, 2R is equal to or less than the reference value SET for starting the slip control, and the slip control is executed. If it is determined that it is not necessary, the flow returns to step S10 after setting the slip flag SF to 0.

As shown in FIG. 10, in the calculation control of the slip value S, as shown in FIG. 10, after a detection signal output from each sensor is inputted in a step S11, in a step S12, it is determined whether or not the traveling road of the vehicle is a rough road. Determine whether or not. That is, when traveling on a rough road, the wheels frequently contact and separate from the road surface according to the unevenness of the road surface, and when the wheels separate from the road surface, the load decreases and the wheels are accelerated, and when the wheels contact the road surface, As the load increases, the wheels decelerate, and the acceleration / deceleration changes are repeated in a short time. Therefore, in the rough road determination means 53, each wheel 1L, 1R, 2
L and 2R accelerations are obtained, and the number of times that the acceleration fluctuates beyond a positive threshold value and a negative threshold value is measured. It is determined whether or not the vehicle is traveling on a rough road by comparing the obtained reference value.

If NO is determined in the above step S12 and it is confirmed that the vehicle is traveling on a good road, in step S13, the rotation of the left driving wheel 2L detected by the driving wheel speed detecting means 51L is performed. By subtracting the rotational speed VFL of the left driven wheel 1L detected by the driven wheel speed detection means 52L from the speed VRL, the slip value S of the left driving wheel 2L is obtained, and the driving wheel speed detection means 51
By subtracting the rotational speed VFR of the right driven wheel 1R detected by the driven wheel speed detection means 52R from the rotational speed VRR of the right driven wheel 2R detected by R, the slip value S of the right driven wheel 2R is set to the first slip value S. It is determined in the control unit 55. Then, in step S14, the slip values S are output to the output control means and the braking force control means.

The determination in step S12 is YES,
If the vehicle is found to be traveling on rough roads,
In step S15, it is determined whether the vehicle is in a straight-ahead state by comparing the steering wheel steering angle with a preset reference steering angle. If this determination result is NO and it is confirmed that the vehicle is in a turning state,
Proceeding to step S13, the above control is executed. If YES is determined in step S12 and it is confirmed that the vehicle is traveling straight on a rough road, step S1 is executed.
At 6, the rotational speed VRL of the left drive wheel 2L is
By subtracting the average value (VRL + VFR) / 2 of the rotation speed VFL of the left driven wheel 1L and the rotation speed VFR of the left driven wheel 1R, the slip value S of the left driving wheel 2L is obtained, and the rotation of the right driving wheel 2R is obtained. The second control unit 56 calculates a slip value S of the right driving wheel 2R by subtracting the average value (VRL + VFR) / 2 from the speed VRR, and then proceeds to step S14 to output the slip values S to the output. Output to the control means and the braking force control means.

Next, the output control of the engine 3 will be described with reference to FIG.
This will be described based on the flowchart shown in FIG. First, in step S21, the slip flag S
It is determined whether or not F has changed from 0 to 1, that is, whether or not the present time is the start time A of the slip control shown in FIG. If the determination result is YES, in step S22, as shown in FIG. 12, the initial setting value of the sub-throttle valve 37, that is, the value at the time of starting the slip control is obtained from the map in which the vehicle speed and the road surface maximum friction coefficient μmax are set as parameters. After reading the rapid decrease SM of the sub-throttle opening, in step S23, the actuator 38 is operated in accordance with the initial set value SM to reduce the opening of the sub-throttle valve 37 and control the opening Tn of the intake passage 33. I do.

If NO is determined in step S21 and it is confirmed that the slip control has already been started, in step S24, the opening degree TH · M of the sub-throttle valve 37, that is, the rear wheel After reading the operation amount of the actuator 38 necessary to make the slip values S of 2L and 2R equal to or less than the target value SET, step S
Proceeding to 23, the actuator 38 is operated to control the opening degree Tn of the intake passage 33.

Next, in step S25, the rear wheels 2
The slip value S of L, 2R is the target value SE for slip control.
It is determined whether or not it has become equal to or less than T. If it is confirmed that the slip value S is still larger than the target value SET, the routine returns. Step S25
Is determined to be YES, and when it is confirmed that the slip value S of the rear wheels 2L and 2R has converged to or below the target value SET for slip control, in step S26, the slip flag SF is set to 0 and the engine is set. The output control of No. 3 is ended.

The braking force control for the rear wheels 2L and 2R is performed by the control shown in FIG.
Control of the pressure increase phase centering on the differential control shown in FIG. 3 (control of phase 0), control of the pressure reducing phase centering on the differential control shown in FIG. 14 (control of phase 1), and FIG.
The control has three types of control modes (control of phase 2) of the pressure increasing / decreasing phase in which the differential control and the proportional control shown in (1) are combined. In the pressure increase phase shown in FIG. 13, Z indicates a brake fluid pressure holding zone,
When the acceleration G of L, 2R is on the deceleration side, the brake fluid pressure is set to be in a holding state. In the pressure increase phase, Nn indicates a pressure increase zone of the brake fluid pressure, and as the absolute value of the acceleration G of the rear wheels 2L and 2R located on the pressure increase side increases (the value of n increases), The brake fluid pressure is set so as to increase the pressure increasing speed.

In the pressure reduction phase shown in FIG. 14, Pn increases as the absolute value of the acceleration G of the rear wheels 2L, 2R located on the deceleration side increases (the value of n increases). 4 shows a brake fluid pressure reduction zone set to be as follows. The pressure reduction phase is configured such that when the acceleration G of the rear wheels 2L, 2R is on the speed increasing side, the pressure is set in the holding zone Z and the brake fluid pressure is held.

The pressure increasing / decreasing phase shown in FIG. 15 includes a pressure increasing zone Nn, a pressure decreasing zone Pn, and a holding zone Z, and the control state of the brake fluid pressure is the acceleration G of the rear wheel 2L.
And the deviation speed EN of the rear wheels 2L and 2R are stored as a map set as parameters. The deviation speed EN is a value set based on the difference between the slip value S of the rear wheels 2L and 2R obtained by the first control unit 55 and the second control unit 56 and the braking force control target value SBT. When the vehicle is traveling straight on a rough road, the value obtained by the second control unit 56 is used as the slip value S. In other cases, the first control unit 55 Use the calculated value.

The braking force control including the combination of the pressure increasing phase, the pressure decreasing phase, and the pressure increasing / decreasing phase is executed based on the flowchart shown in FIG. The braking force control for the rear wheels 2L and 2R is performed independently for the left and right wheels, but the contents are basically the same. Therefore, only the control operation for the left rear wheel 2L will be described below.

When the control operation starts, first, in step S31, a target value SBT for braking force control is obtained. That is, as shown by the broken line in FIG. 5, a basic slip value STB0 for braking force control is obtained from a map in which the vehicle speed and the maximum friction coefficient μmax of the road surface are set as parameters.
Is read out, and the target value SBT for braking force control is calculated by multiplying this value by each of the gain coefficients shown in FIGS.

Next, in step S32, the rear wheels 2L
It is determined whether or not the slip value S is larger than the target value SBT. If the determination is YES, the process proceeds to step S3.
At 3, it is determined whether the braking force control is already being executed. That is, it is determined whether or not the current time point is in the braking force control state after the time point B in FIG.

If NO is determined in step S33 and it is confirmed that the braking force control has not been started yet, it is determined that the current time is the time point B, and step S33 is performed.
At step 34, the pressure increase control of phase 0 is started, the convergence control of the initial spin is executed, and the flag indicating the phase state is set to 0 to indicate that the pressure is in the pressure increase phase state. Then, in step S35, the rear wheel 2
It is determined whether or not the slip value S of L has converged below the target value SBT for controlling the braking force. If the determination is YES, the process proceeds to step S36 to shift to the phase 2 pressure increasing / decreasing control state. , The flag indicating the phase state is set to 2 to indicate that it is in the pressure increasing / decreasing phase state.

If NO in step S35, the process proceeds to step S37, where the current rear wheel 2
The deviation EN of the slip value S of L and the slip deviation at the peak (the difference between the slip value S of the rear wheel 2L at the peak of the initial spin and the target value SET for slip control) PEN
It is determined whether the ratio is smaller than 0.7. If the decision result in the step S37 is NO, and it is confirmed that the deviation EN of the current slip value S is a large value close to the peak slip deviation PEN, the process returns to the step S34 and returns to the phase 0. Pressure increase control is continued.

On the other hand, if the result of the determination in step S37 is Y
If it is ES, and it is confirmed that the deviation EN of the current slip value S is smaller than the slip deviation PEN at the peak, the process shifts to the phase 1 pressure reduction control state in step S38, Is set to 1 to indicate that it is in the decompression phase state.

Next, in step S39, it is determined whether or not the deviation EN of the slip value S is larger than the slip deviation PEN at the peak, and in step S40, the differential value of the deviation EN, that is, It is determined whether or not the change rate DENRL of the slip value S of the wheel 2L is larger than 2.0G. And the above step S3
When YES is determined in each of the steps 9 and 40, the process proceeds to step S36, and the pressure increase / decrease control is executed.

If the determinations in steps S39 and S40 are both NO, the current slip value S is set to the slip control target value SET in step S41.
Is determined as follows, and if NO is determined, the process returns to step S38 to continue the phase 1 pressure reduction control. If YES is determined in the step S41 and it is confirmed that the slip value S has converged to an appropriate value, the braking force control ends in a step S42.

If it is determined YES in step S33 and it is confirmed that the braking force control is already being executed at the present time, in step S43, the deviation EN of the current slip value S is set to the value at the time of the peak. It is determined whether or not the value has become larger than the slip deviation PEN. If this determination result is YES and it is confirmed that the slip value S of the rear wheel 2L has increased again, the above-described step S34 is performed.
To shift to the phase 0 pressure increase control state.

If the determination in step S43 is NO, and it is confirmed that the deviation EN of the slip value S of the rear wheel 2L is equal to or smaller than the peak slip deviation PEN,
In step S44, the slip value S of the rear wheel 2L is set.
It is determined whether or not the rate of change DEN is greater than a preset reference acceleration of 3.0 G, that is, whether or not the slip value S of the rear wheel 2L has a remarkable increasing tendency. If it is determined as YES in the above step S44 and it is confirmed that the slip value S of the rear wheel 2L has a remarkable increasing tendency,
Returning to step S34, the pressure increase / decrease control of phase 0 is executed.

If the determination in step S44 is NO, and it is confirmed that the slip value of the rear wheel 2L does not tend to increase significantly, the current slip value S is set to the target value for slip control in step S45. It is determined whether the value has become equal to or less than the value SET. If NO is determined in the step S45, the phase 2 is determined in the step S46.
Is continued. On the other hand, if YES is determined in the step S45 and it is confirmed that the slip value S has converged to an appropriate value, the process shifts to step S42 to end the braking force control.

As described above, two kinds of control units 55 and 56 are provided in the control means for executing the slip control, and the control unit to be used is selected according to the state of the traveling road surface or the like. Corresponding appropriate slip control can be executed. That is, the vehicle runs on a good road,
Alternatively, in a normal traveling state in which the steering angle is equal to or larger than the reference value and the vehicle is in a predetermined turning state, the slip values S of the drive wheels 2L and 2R are obtained independently for the left and right sides, and then the slip values S
Is compared with a target value SET for slip control to determine whether or not to execute the slip control. Therefore, the slip value S can be accurately detected without being affected by the difference between the inner and outer wheels generated at the time of turning. Thus, the slip control can be properly performed.

On the other hand, when the vehicle is traveling straight on a rough road, the driven wheel speed is a common value, that is, the average value of the rotation speeds of the left and right driven wheels 1L and 1R (VRL + VFR).
The slip value S of the left and right drive wheels 2L, 2R using
Is determined, and it is determined whether or not to execute the slip control in accordance therewith. Therefore, it is possible to reduce noise generated due to the vibration of the wheels according to the unevenness of the traveling road. Therefore, it is possible to effectively prevent the malfunction of the control means without employing a means for smoothing the control variable by a filter as in the conventional device.

Further, as described above, the deviation speed EN is obtained based on the difference between the slip value S of the rear wheels 2L and 2R and the braking force control target value SBT, and the braking force control is performed based on the deviation speed EN. In the case where the control amount at the time of executing the control is set, for example, the control zone at the time of executing the pressure increasing / decreasing control of the phase 2 is set, the malfunction of the control means caused by the noise is prevented. Further, it is possible to effectively prevent the pressure from being reduced in a state where the brake fluid pressure must be increased, or to prevent the reverse phenomenon from occurring, and to stabilize the control state.

In the above embodiment, the braking force control mode includes a pressure increase phase of phase 0, a pressure reduction phase of phase 1, and a pressure increase / decrease phase of phase 2.
Although the description has been given of the case of having the various control modes, after executing the pressure increase control of the phase 0 when the initial spin occurs,
The configuration of the present invention can also be adopted in a slip control device configured to directly shift to the pressure increase / decrease control state of phase 2.

[0052]

As described above, according to the present invention, when the vehicle is traveling straight on a rough road, the slip of the drive wheel is determined by using the average value of the left and right driven wheel speeds as the rotational speed of the driven wheel. calculated values, the normal time other than the straight in the rough road, since the structure left and right drive wheels slip value or the like to determine independently, Ya detection error of the slip value corresponding to the inner and outer rings difference caused during turning of the vehicle In addition, it is possible to prevent malfunction of the control means due to noise or the like caused by the vibration of the wheels when traveling on a rough road, and to reduce the control delay of the drive wheels without causing a control delay or the like when a filter is used. There is an advantage that the slip control can be executed properly.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a vehicle slip control device according to the present invention.

FIG. 2 is an overall system diagram of the slip control device.

FIG. 3 is a time chart showing a control operation of the slip control device.

FIG. 4 is a flowchart showing a main control operation of slip control.

FIG. 5 is a map showing a relationship between a basic set value of a control reference value and a maximum friction coefficient.

FIG. 6 is a map showing a gain coefficient using vehicle speed as a parameter.

FIG. 7 is a map showing a gain coefficient using an accelerator opening as a parameter.

FIG. 8 is a map showing a gain coefficient using a steering angle as a parameter.

FIG. 9 is a table showing gain coefficients corresponding to a traveling mode.

FIG. 10 is a flowchart showing a control operation for calculating a slip value.

FIG. 11 is a flowchart showing an engine output control operation.

FIG. 12 is a map for determining an initial setting value of a sub-throttle opening.

FIG. 13 is a map of a pressure increasing phase.

FIG. 14 is a map of a pressure reduction phase.

FIG. 15 is a map of a pressure increasing / decreasing phase.

FIG. 16 is a flowchart showing a braking force control operation.

[Explanation of symbols]

 2 Rear Wheel (Drive Wheel) 51 Drive Wheel Speed Detecting Means 52 Driven Wheel Speed Detecting Means 53 Rough Road Judging Means 54 Straight Away State Detecting Means 55 First Control Unit 56 Second Control Unit

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazutoshi Nobumoto 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (56) References JP-A-62-265431 (JP, A) JP-A Sho 62-265432 (JP, A) JP-A-2-41962 (JP, A) JP-A-1-271617 (JP, A) JP-A-3-281468 (JP, A) JP-A-2-45461 (JP, A) U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60T 8/58 B60K 41/20 F02D 29/02 311

Claims (1)

(57) [Claims] 1. A driving wheel speed detecting means for detecting rotational speeds of left and right driving wheels, a driven wheel speed detecting means for detecting rotational speeds of left and right driven wheels, and a detection signal outputted from these detecting means. A slip control device for a vehicle that controls the output or braking force of the engine to converge the slip value of the drive wheel to a target value when it is confirmed that the drive wheel has slipped, Bad road determining means for determining whether or not the traveling road is a bad road; straight traveling state determining means for determining whether or not the vehicle is in a straight traveling state; and the drive wheel speed detecting means and the driven wheel speed The slip control of the left driving wheel is executed based on the rotation speed of the left driving wheel and the rotation speed of the left driven wheel detected by the detecting means, and the right rotation is performed based on the rotation speed of the right driving wheel and the rotation speed of the right driven wheel. Drive wheel pickpocket A first control unit that executes the road control, and the rotational speeds of the left and right drive wheels and the left and right driving wheels when the vehicle is traveling straight on a rough road by the rough road determining unit and the straight traveling state detecting unit. And a second control unit that executes slip control of each drive wheel based on the average rotational speed of the driven wheels.