JPH05105061A - Traction controller for vehicle - Google Patents

Abstract

PURPOSE:To prevent any control hunting from occurring by making decelerating slip brake control take preference over all the control in two changeover conditions, one from decelerating slip brake control to accelerating slip brake control, and the other from the accelerating slip brake control to the decelerating slip brake control. CONSTITUTION:At the occurrence of a decelerating slip, braking force is given by a decelerating slip detecting means (a) at a decelerating slip brake control system (b), and at the occurrence of an accelerating slip, the braking force is given by an accelerating slip detecting means (d) at an accelerating slip brake control system (e), respectively. In succession, when an operating request is outputted out of an accelerating slip brake control operation requesting means (f) during the decelerating slip brake controlling, it is selected to the accelerating slip brake control after a severe first changeover condition is satisfied in a control changeover means (g). Conversely, in the case of an operating request out of a decelerating slip brake control operation requesting means (c) during the decelerating slip brake control, it is selected to the decelerating slip brake control after a gentle second changeover condition is satisfied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle traction control device equipped with both a deceleration slip brake control system and an acceleration slip brake control system.

[0002]

2. Description of the Related Art Conventionally, as a traction control device for a vehicle equipped with both a deceleration slip brake control system (antilock control means) and an acceleration slip brake control system (brake control means of the driving force control means), For example, the device described in Japanese Patent Laid-Open No. 1-342020 is known.

According to the above-mentioned conventional sources, when the same wheel speed information is used as control information and the deceleration slip brake control system and the acceleration slip brake control system which share the brake control actuator are switched to each other, the control state before switching is used. The technique for setting the initial control condition after switching is disclosed.

[0004]

However, in the above traction control device for a vehicle, when the acceleration slip brake control operation request is output during the deceleration slip brake control, the acceleration slip brake control is immediately switched to the acceleration slip brake control. When a deceleration slip brake control operation request is output during brake control, the switching conditions are the same, such as immediately switching to deceleration slip brake control.Therefore, as described below, deceleration slip brake control and acceleration There has been a problem that interference (hunting) occurs in the control in which the slip brake control is repeated, and particularly the braking performance by the deceleration slip brake control deteriorates.

For example, when a brake operation is performed while traveling on a low friction coefficient road, the acceleration slip brake control is switched to the deceleration slip brake control.
As shown in, when the driven wheel speed decreases due to the deceleration slip control, it is erroneously determined that the difference between the drive wheel speed and the driven wheel speed is caused by the acceleration slip, and the deceleration slip brake control immediately changes to the acceleration slip brake control. Switched,
After that, when it is determined that the vehicle is in deceleration slip during the acceleration slip brake control, the control is switched to the deceleration slip brake control, so that both controls are repeated.

The present invention has been made by paying attention to the above problems, and secures braking performance in a vehicle traction control device equipped with both a deceleration slip brake control system and an acceleration slip brake control system. An object is to prevent control hunting between deceleration slip brake control and acceleration slip brake control while giving priority.

[0007]

In order to solve the above-mentioned problems, in the vehicle traction control device of the present invention, the switching condition from the deceleration slip brake control to the acceleration slip brake control and the acceleration slip brake control to the deceleration slip brake control are changed. The switching condition is changed so that the deceleration slip brake control is prioritized.

That is, as shown in the claim correspondence diagram of FIG. 1, deceleration slip detection means a for detecting deceleration slips of the driven wheel and the drive wheel, and each wheel for suppressing the wheel lock according to the occurrence state of the deceleration slip. Deceleration slip brake control system b for applying a braking force to the vehicle, deceleration slip brake control operation request means c for outputting a deceleration slip brake control operation request signal based on the detection of deceleration slip of at least one wheel, and acceleration slip of the driving wheel are detected. Acceleration slip detection means d, an acceleration slip brake control system e that applies a braking force to the driving wheels to suppress the acceleration slip depending on the occurrence of the acceleration slip, and an acceleration slip brake control operation request signal based on the detection of the acceleration slip. Acceleration slip brake control operation requesting means f for outputting If the acceleration slip brake control operation request is output during control, the mode is switched to the acceleration slip brake control after satisfying the strict first switching condition, and if the deceleration slip brake control operation request is output during the acceleration slip brake control, Control switching means g for switching to the deceleration slip brake control after the second switching condition is satisfied is provided.

The first switching condition may be the end of the deceleration slip brake control, and the second switching condition may be a condition corresponding to the deceleration slip state of the driven wheels.

[0010]

When a deceleration slip occurs, such as during low-friction coefficient road braking or sudden braking, in the deceleration slip brake control system b, the detected value from the deceleration slip detection means a for detecting the deceleration slip of the driven wheels and the driving wheels. Braking force is applied to each wheel in order to suppress wheel lock depending on the occurrence of deceleration slip due to.

When an acceleration slip occurs during acceleration, starting or the like, the acceleration slip brake control system e determines the occurrence of the acceleration slip based on the detection value from the acceleration slip detecting means d for detecting the acceleration slip of the driving wheels. Accordingly, braking force is applied to the drive wheels to suppress acceleration slip.

During the deceleration slip brake control,
When the acceleration slip brake control operation requesting unit f that outputs the acceleration slip brake control operation requesting signal outputs the acceleration slip brake control operation request, the control switching unit g decelerates the slip brake control after satisfying the strict first switching condition. Is switched to acceleration slip brake control.

Further, during the acceleration slip brake control, the deceleration slip brake control operation request means c for outputting the deceleration slip brake control operation request signal based on the detection of the deceleration slip of at least one wheel outputs the deceleration slip brake control operation request. In this case, the control switching means g switches from the acceleration slip brake control to the deceleration slip brake control after satisfying the gentle second switching condition.

[0014]

[Embodiment] The configuration will be described.

FIG. 2 is an overall view of a braking / driving system control system for a rear-wheel drive vehicle to which the vehicle traction control device according to the embodiment of the present invention is applied.

In this rear-wheel drive vehicle, the throttle control for controlling the motor throttle opening so that the rear-wheel slip ratio falls within the optimum allowable range when acceleration slip occurs and the left and right rear wheels independently when acceleration slip occurs. A traction control system (equal to an acceleration slip brake control system on the brake control side) that is used together with a brake control that applies braking force is provided, and front and rear wheel brake fluid pressure control is performed to prevent wheel lock during deceleration slip. It is equipped with an anti-skid brake control system (corresponding to a deceleration slip brake control system). And
Centralized electronic control of these systems is performed by a traction control system & anti-skid brake control system electronic control unit TCS / ABS-ECU (hereinafter abbreviated as TCS / ABS-ECU).

The TCS / ABS-ECU includes a right front wheel speed sensor 1
Right front wheel speed sensor value VWFR, left front wheel speed sensor 2 left front wheel speed sensor value VWFL, right rear wheel speed sensor 3 right rear wheel speed sensor value VWRR, and left rear wheel speed sensor 4 Left rear wheel speed sensor value VWRL, lateral acceleration sensor value YG from lateral acceleration sensor 5, switch signal SWTC from TCS switch 6, switch signal SWST from brake lamp switch 7, throttle control module TCM (hereinafter, Throttle 1 actual opening DKV from TCM)
And the automatic transmission control unit A /
Gear position signal and shift-up signal from TC / U (hereinafter abbreviated as A / TC / U) and engine rotation from the engine centralized electronic control unit ECCS C / U (hereinafter abbreviated as ECCS C / U) The number signal and the second throttle signal TVO2 or the like from the second throttle sensor 17 are input.

Then, from the TCS / ABS-ECU, the acceleration slip is detected, and the throttle 2 as a throttle opening / closing signal is detected.
The target opening DKR is output to TCM, and the solenoid signal as the brake pressure increase / decrease signal is output to each solenoid valve of the shared hydraulic unit TCS / ABS-HU (hereinafter abbreviated as TCS / ABS-HU). .. The throttle control side of this traction control is called TCS throttle control, and the brake control side is called TCS brake control.

The TCS / ABS-ECU detects deceleration slip and outputs a solenoid signal as a brake pressure increasing / decreasing signal to each solenoid valve of the TCS / ABS-HU. This anti-skid brake control is called ABS brake control.

In addition to the above output, the TCS / ABS-ECU outputs a lighting command to the TCS fail lamp 14 when the TCS fails, and outputs a lighting command to the TCS operation lamp 15 while the TCS is operating.

The TCM is a control circuit centered on a throttle motor drive circuit, which receives the first throttle signal TVO1 from the first throttle sensor 16 and outputs it to the TCS / ABS-ECU as the throttle 1 actual opening DKV. Or input the second throttle signal TVO2 from the second throttle sensor 17 as feedback information for the throttle 2 target opening DKR, or input the throttle 2 target opening DK from the TCS / ABS-ECU.
A motor drive current IM is applied to the throttle motor 18 based on R.

Here, the first throttle valve 19 provided with the first throttle sensor 16 is the accelerator pedal 2
The second throttle valve 21, which is a valve that operates in conjunction with 0, is provided in the engine intake passage 22 in series with the first throttle valve 19 and is opened and closed by the throttle motor 18. It is a valve that is used.

As a peripheral system, the traction control system includes an air flow meter AFM as shown in the figure.
It has an ECCS C / U and an injector, and an engine centralized electronic control system that centrally controls fuel injection control, ignition timing control, idle speed correction, etc. is installed. When the ON signal is input, control for selecting a smaller valve opening of the first throttle signal TVO1 and the second throttle signal TVO2 (select low control) is performed to correct the transient characteristics, and the canister control and EGR control are performed. It will be canceled.

As a peripheral system, as shown in the figure, it has an A / TC / U and a shift solenoid, and is equipped with an automatic transmission control system for performing gear shift control, lockup control, etc. The gear position signal and shift-up signal are fetched from TCS / ABS-ECU.

Further, as a peripheral system, as shown in the figure, an ASCD actuator is provided, and a constant speed traveling control system for automatically controlling the vehicle speed so as to maintain the set vehicle speed is mounted, so as to prevent control interference, When the ON signal of the traction switch signal TCS SW is input, the opening control of the first throttle valve 19 is stopped, and when the OFF signal of the TCS SW is input, the return speed of the first throttle valve 19 is made gentle.

FIG. 3 is a hydraulic circuit diagram showing a brake hydraulic pressure control system commonly used for TCS brake control and ABS brake control for the left and right rear wheels independently.

This brake fluid pressure control system includes a brake pedal 27, a hydraulic booster 28, a master cylinder 30 having a reservoir 29, wheel cylinders 31, 32, and
33, 34 and shared hydraulic unit TCS / ABS-HU
, Pump unit PU, and first accumulator unit
AU1, 2nd accumulator unit AU2, front wheel side damping unit FDPU, rear wheel side damping unit RD
It is equipped with PU.

The TCS / ABS-HU has a first switching valve 35a.
, Second switching valve 35b, left front wheel pressure increasing valve 36a
And right front wheel pressure increasing valve 36b and left rear wheel pressure increasing valve 36
c, right rear wheel pressure increasing valve 36d, left front wheel pressure reducing valve 3
7a, a right front wheel pressure reducing valve 37b, a left rear wheel pressure reducing valve 37c, a right rear wheel pressure reducing valve 37c, a front wheel side reservoir 38a, a rear wheel side reservoir 38b, and a front wheel side pump 39.
a, the rear wheel side pump 39b, and the front wheel side damper chamber 40a
And a rear wheel side damper chamber 40b and a pump motor 41.

During normal braking or ABS brake control, both switching valves 35a and 35b are turned off as shown in order to introduce the hydraulic pressure from the master cylinder 30.
When the TCS brake is controlled, both switching valves 35a and 35b are turned to the ON position in order to introduce the hydraulic pressure from the second accumulator unit AU2. Then, for example, in the pressure increasing mode of the TCS brake control, both control valves 36c, 36d, 37c, 37d are as shown in the drawing.
In the OFF position and in the holding mode, the booster valve 36
Only c and 36d are set to the ON position, and in the depressurization mode, both control valves 36c, 36d, 37c and 37d are set to the ON position, the brake fluid from the wheel cylinders 33 and 34 is stored in the rear wheel side reservoir 38b, and further, By the rotation of the rear wheel side pump 39b, it is returned to the rear wheel side damper chamber 40b.

The first accumulator unit AU1 is used as a hydraulic pressure source for the hydraulic booster 28, and the second accumulator unit AU2 is used as a hydraulic pressure source for TCS brake control. Predetermined accumulator pressure is maintained by the common pump unit PU that draws in.

The front wheel side damping unit FDPU and the rear wheel side damping unit RDPU are shared hydraulic units TCS / AB in order to improve pedal feeling.
The influence of the change in hydraulic pressure on the S-HU is suppressed from affecting the master cylinder 30.

The operation will be described.

(B) Traction control action FIG. 4 is a control block diagram showing an outline of traction control performed by the TCS / ABS-ECU. The traction control logic can be roughly classified into the following four types of control.

(1) Calculation of Actual Slip State The signals of the wheel speed sensors 1, 2, 3, 4 are filtered, and the actual slip state (slip amount, slip amount difference value) is calculated based on the filtered wheel speed value. ) Is calculated (corresponding to deceleration slip detection means and acceleration slip detection means).

(2) Calculation of target slip state The signal of the lateral acceleration sensor 5 is filtered to calculate a target slip state suitable for the running state based on the turning / straight ahead determination based on the lateral acceleration and the vehicle speed.

(3) TCS brake control Comparing the actual slip state and the target slip state, the required brake pressure increasing / decreasing speed (control duty ratio) is calculated and output to TCS / ABS-HU.

(4) TCS throttle control Comparing the actual slip state and the target slip state, the necessary throttle opening and opening / closing speed are calculated and output to the TCM.

This control logic is characterized by low μ to high μ.
In order to secure the limit detectability (steering force, skill sound, etc.) based on the base chassis performance according to each road surface condition and to obtain active safety, the allowable slip state according to the magnitude of lateral acceleration, The allocation of throttle / brake control has been decided.

Further, in order to secure stability during shifting and improve controllability at each gear position, throttle / brake control is performed according to the gear position.

Further, in order to suppress slip hunting and realize a smooth acceleration feeling and controllability, and also to realize a responsive engine torque increase / decrease control, optimal throttle control according to the engine speed is performed.

(B) ABS brake control action When the deceleration slip of each wheel exceeds the deceleration slip threshold value during braking, the solenoid signal as a brake pressure increasing / decreasing signal is independently applied to each wheel of each solenoid valve of TCS / ABS-HU. It is done by outputting to.

By this control, the wheel lock is suppressed when the braking force is likely to occur and the wheel lock is likely to occur, such as when the road is braked with a low friction coefficient or during sudden braking.
The braking stability of the vehicle and the braking distance can be shortened.

(C) Brake control operation request signal output process FIG. 5 is a flow chart showing the flow of the ABS brake control operation request signal output process operation performed by the TCS / ABS-ECU. Each step will be described below (deceleration slip). Equivalent to brake control operation request means).

At step 50, the right front wheel speed sensor value VWF
R, left front wheel speed sensor value VWFL, right rear wheel speed sensor value VWRR
, The left rear wheel speed sensor value VWRL is read. In step 51, it is determined whether the deceleration slip amount calculated based on the read wheel speed signal is equal to or greater than the deceleration slip threshold value. When YES is determined in at least one of the front and rear wheels in step 51, the process proceeds to step 52, and AS = 1 is output as the ABS brake control operation request signal. When NO is determined in the step 51, the process proceeds to a step 53, and AS = 0 is output as the ABS brake control non-operation signal.

FIG. 6 is a flowchart showing the flow of the TCS brake control operation request signal output processing operation performed by the TCS / ABS-ECU. Each step will be described below (corresponding to acceleration slip brake control operation request means).

In step 60, the right front wheel speed sensor value VWF
R, left front wheel speed sensor value VWFL, right rear wheel speed sensor value VWRR
, The left rear wheel speed sensor value VWRL is read. In step 61, it is judged whether the acceleration slip amount calculated based on the read wheel speed signal is equal to or more than the acceleration slip threshold value. At least one of the left and right rear wheels in step 61
If YES is determined in the wheel, the process proceeds to step 62,
TS = 1 is output as the TCS brake control operation request signal. When NO is determined in step 61, the process proceeds to step 63, in which TCS brake control non-operation signal T
S = 0 is output.

(D) ABS → TCS control switching action FIG. 7A shows ABS to TCS switching performed by the TCS / ABS-ECU.
Each step will be described below (corresponding to control switching means) with a flowchart showing the flow of the control switching processing operation to the CS.

At step 70, it is judged if the ABS brake control is in operation.

In step 71, it is judged whether or not the TCS brake control operation request signal TS = 1 is output.

At step 72, it is judged if the throttle opening TVO is equal to or larger than the vehicle speed-corresponding throttle opening calculation value θ (V).

The throttle opening TVO is obtained by selecting the smaller one of the first throttle opening TVO1 and the second throttle opening TVO2, and the vehicle speed-corresponding throttle opening calculation value θ (V) is, for example, , Given by the following formula:

Θ (V) = α · VFTF ² + β VFTF; front wheel speed average value In step 73, the ABS brake control non-operation signal AS
It is determined whether or not = 0 is output.

When the above steps 70, 71 and 72 are satisfied, the routine proceeds to step 74, where a TCS throttle control start command is output.

When the above steps 70, 71, 72 and 73 are satisfied, the routine proceeds to step 75, where a TCS brake control start command is output.

Therefore, in the control switching from ABS to TCS, when the throttle opening condition of step 72 is satisfied, as shown in the time chart of FIG.
When the TCS brake control operation request signal TS = 1 is output at time t1 during the S brake control, the TCS throttle control is started immediately. However, the TCS brake control will be started after waiting the time t2 at which the ABS brake control non-operation signal AS = 0 is output. Thus, from time t1 to time t2, the ABS brake control and the TCS throttle control operate simultaneously, and the time t
At time 2, the ABS brake control is switched to the TCS brake control.

For example, when the TCS brake control operation request signal TS = 1 is output during the ABS brake control, and when the TCS brake control is immediately switched to, when the TCS brake control is performed in addition to the wheel cylinder residual pressure, the accumulator outputs When the TCS brake control is performed, a sufficient amount of increased pressure is applied to cause a feeling of deceleration, and when the TCS brake control is performed, there is residual liquid in the brakes during ABS brake control, so that sufficient pressure reduction control is performed. However, the brakes tend to drag and a feeling of deceleration occurs.

On the other hand, when the TCS throttle control is advanced between the time t1 and the time t2, the ABS
It is possible to reduce the brake pressure in the brake control,
Excessive brake control is suppressed, and the pumps 39a and 39b are actuated by continuing the ABS brake control from time t1 to time t2.
The residual liquid of the brake in 38b can be removed.

Further, when the TCS brake control operation request signal TS = 1 is output due to the occurrence of the acceleration slip, the condition that the throttle opening TVO is equal to or larger than the vehicle speed corresponding throttle opening calculated value θ (V) in step 72 is satisfied. Imposing TCS
The reason why the throttle control is switched is that when the throttle opening TVO is small and the TCS throttle control is immediately switched, the sudden return of the second throttle valve 21 delays not only the engine brake but also the brake pressure reduction. As a result, the rear wheel tends to lock, which reduces stability. Also, the calculated throttle opening θ for vehicle speed
(V) is the value that gives the running resistance at that time by the sum of the air resistance (α · VFTF ² ) proportional to the square of the vehicle speed VFTF and the rolling resistance β. The larger the running resistance, This is because a large value is used as the comparison reference value for the throttle opening TVO.

(E) TCS → ABS control switching action FIG. 7B shows the TCS / ABS-ECU to TCS to A
Each step will be described below (corresponding to control switching means) with a flowchart showing a flow of control switching processing operation to the BS.

At step 80, it is judged if the TCS brake control is in operation.

In step 81, it is judged whether or not the ABS brake control operation request signal AS = 1 is output.

In step 82, it is judged whether or not the ABS brake control operation request signal ASFFR = 1 for the right front wheel and the ABS brake control operation request signal ASFFL = 1 for the left front wheel are simultaneously output.

At step 83, it is judged if the throttle opening TVO is smaller than the vehicle speed-corresponding throttle opening calculated value θ (V).

At step 84, it is judged if the TCS brake control non-operation signal TS = 0 is output.

Steps 80, 81, 82 or steps 80, 81, 83 or steps 80, 81, 84
If either of the above is satisfied, the process proceeds to step 85 and AB
An S throttle control start command is output. When the process proceeds to step 85 after step 82 or step 83, the ABS throttle control start command is output and the TCS brake control stop command is output.

Therefore, the control switching from TCS to ABS is performed in step 82 as shown in the time chart of FIG.
When the ABS brake control operation request condition for the left and right front wheels of the vehicle is satisfied, the ABS brake control is immediately started when the ABS brake control operation request signal AS = 1 is output at time t3 during the TCS brake control. ..

As described above, the reason why the operation request of the front wheels which are the driven wheels is set as the switching condition is that the ABS operation request of the driven wheel is more accurate and earlier than that of the drive wheel. Further, the reason why the operation demands on the left and right front wheels are set as the switching condition is that, for example, when the low μ road braking in which the left and right front wheels are both slippery easily, the ABS actuation requests are easily issued to the left and right rear wheels.
It is preferable to give priority to S, and when only one of the left and right front wheels is requested to perform ABS operation, it often occurs due to road surface disturbance, wheel load change, bump overrun, split μ road, etc. , In this case, immediately TCS
This is because the vehicle stability is often impaired when the vehicle is stopped.

When an ABS operation request is issued during the TCS control, when the throttle opening condition in step 83 or the output condition of the TCS brake control non-operation signal TS = 0 in step 84 is satisfied, the ABS control is switched to. ..

The effect will be described.

(1) The condition for switching from the ABS brake control to the TCS brake control is the termination of the ABS brake control, and the condition for switching from the TCS brake control to the ABS brake control is the ABS operation request for the left and right front wheels. Since the device is configured to perform different switching so as to give priority, it is possible to prevent control hunting between the ABS brake control and the TCS brake control while giving priority to ensuring braking performance.

(2) At the time of control switching from TCS to ABS,
When the ABS brake control operation request is issued to the left and right front wheels, the ABS brake control is started immediately, so that the braking performance is improved at the time of low friction coefficient road braking or sudden braking without impairing the vehicle stability. Can be planned.

(3) At the time of control switching from ABS to TCS,
Since the TCS throttle control is performed immediately, but the TCS brake control is performed after the ABS brake control is completed, it is possible to prevent the occurrence of a deceleration feeling due to excessive brake control and the deceleration feeling due to the brake dragging.

(4) When the TCS brake control operation request signal TS = 1 is output due to the occurrence of the acceleration slip, the throttle opening TVO is the throttle opening calculated value θ corresponding to the vehicle speed.
(V) Since the TCS control is entered under the condition that the above condition is satisfied, excessive decompression feeling and rear wheels tend to lock like when the TCS control is immediately entered in the small throttle opening range. It is possible to prevent the occurrence of vehicle damage and ensure vehicle stability.

Although the embodiment has been described above with reference to the drawings, the specific structure is not limited to this embodiment.

For example, in the embodiment, the example of application to the traction control system by throttle + brake is shown, but it can be applied to the system which performs traction control only by the brake control.

[0076]

As described above, according to the present invention, a traction control device for a vehicle, in which both a deceleration slip brake control system and an acceleration slip brake control system are mounted, is set forth in claim 1. , The switching condition from deceleration slip brake control to acceleration slip brake control and the switching condition from acceleration slip brake control to deceleration slip brake control are made different so as to give priority to deceleration slip brake control. The effect that the control hunting of the deceleration slip brake control and the acceleration slip brake control can be prevented while securing the priority is obtained.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing a vehicle traction control device of the present invention.

FIG. 2 is an overall view of a braking / driving system control system of a rear-wheel drive vehicle to which the vehicle traction control device of the embodiment is applied.

FIG. 3 is a hydraulic circuit diagram showing a brake fluid pressure control system of a braking / driving system control system to which the vehicle traction control device of the embodiment is applied.

FIG. 4 is a block diagram showing an outline of traction control in the embodiment.

FIG. 5 is a flowchart showing a flow of an ABS brake control operation request signal output processing operation performed by the TCS & ABS electronic control unit of the embodiment apparatus.

FIG. 6 is a flowchart showing a flow of TCS brake control operation request signal output processing operation performed by the TCS & ABS electronic control unit of the embodiment apparatus.

7A is a flowchart showing a flow of control switching processing operation from ABS to TCS performed by a TCS & ABS electronic control unit of the embodiment apparatus, and FIG.
(B) is a flowchart showing a flow of control switching processing operation from TCS to ABS.

FIG. 8 is a time chart when the control is switched from ABS to TCS.

FIG. 9 is a time chart when the control is switched from TCS to ABS.

FIG. 10 is a wheel speed characteristic diagram for explaining control hunting between ABS and TCS in a conventional device.

[Explanation of symbols]

 a deceleration slip detection means b deceleration slip brake control system c deceleration slip brake control operation request means d acceleration slip detection means e acceleration slip brake control system f acceleration slip brake control operation request means g control switching means

Claims (2)

[Claims] 1. A deceleration slip detection means for detecting a deceleration slip of a driven wheel and a drive wheel, and a deceleration slip brake control system for applying a braking force to each wheel so as to suppress a wheel lock according to a situation of occurrence of the deceleration slip. Deceleration slip brake control operation request means for outputting a deceleration slip brake control operation request signal based on the detection of at least one wheel deceleration slip, acceleration slip detection means for detecting an acceleration slip of a driving wheel, and an acceleration slip occurrence condition Acceleration slip brake control system that applies braking force to the driving wheels to suppress acceleration slip, acceleration slip brake control operation request means that outputs an acceleration slip brake control operation request signal based on detection of acceleration slip, and deceleration slip brake control An acceleration slip brake control operation request is output during If it is determined that the strict first switching condition is satisfied, the mode is switched to the acceleration slip brake control, and if the deceleration slip brake control operation request is output during the acceleration slip brake control, the deceleration slip is satisfied after the gradual second switching condition is satisfied. A vehicle traction control device comprising: a control switching means for switching to brake control. 2. The vehicle traction control device according to claim 1, wherein the first switching condition is termination of deceleration slip brake control, and the second switching condition is a condition corresponding to a deceleration slip state of driven wheels. A traction control device for a vehicle.