JP3259478B2 - Wheel 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 wheel slip control device and, more particularly, to a wheel slip control device for suppressing wheel slip generated when starting or running on a slope.

[0002]

2. Description of the Related Art When a driving torque applied to a driving wheel during acceleration of a vehicle is excessively large in relation to a friction coefficient of a road surface, a slip of the driving wheel becomes large and acceleration cannot be performed effectively. Since the driving force generated by the driving wheels becomes maximum when the slip ratio is a predetermined value, the rotation of the driving wheels is controlled so that the slip ratio or the slip amount of the driving wheels becomes a predetermined value. (This control is called traction control: TRC).

[0003] Specific means for controlling the rotation of the drive wheels include reducing the output torque of a drive source such as an engine, operating a brake for suppressing the rotation of the drive wheels, or reducing the output torque. And the operation of the brake are used together.

By providing the above traction control, the occurrence of slip can be prevented, and the stability during traveling on a road surface having a low friction coefficient (low μ road) can be improved. However, when a vehicle is started on an ascending road having a particularly low friction coefficient, such as a snowy road, it is known that the slip amount becomes large under normal traction control and the vehicle cannot be started properly. .

Therefore, when starting on an uphill road,
A slip control device has been proposed in which a slip ratio is set to be lower than that at the time of starting on a flat road so that the vehicle can be started well even on starting on an uphill road having a low friction coefficient. 63-22
No. 2964).

[0006]

However, in traction control executed when the vehicle starts on an uphill road with a low coefficient of friction, even if control is performed to set the slip ratio to a low value, a slip occurs in the drive wheels, and the vehicle may slip. There was a risk of retreating. Hereinafter, the reason why this phenomenon occurs will be described.

[0007] When starting from a stopped state on an uphill road having a low μ road such as an icy road, when the accelerator is depressed to generate a driving force on the driving wheels, a slip occurs on the driving wheels and the μ between the tire and the road surface is increased. (Coefficient of friction) becomes very small, and the driving force obtained on the road surface is greatly reduced. For this reason, depending on the gradient of the uphill road, the vehicle may retreat (downhill) on the uphill road, and the vehicle may not be able to start or uphill.

On the other hand, in traction control, a wheel speed detection sensor is provided for each of the driven wheel and the non-driven wheel, and the output of each sensor is used to determine the drive wheel speed (V
WR) and the non-driving wheel speed (VWF) are detected, and when the driving wheel speed VWR is higher than the non-driving wheel speed VWF (VW
R> VWF), VWR ≦ VWF + C (C is a constant) Control of the driving force is performed.

Here, in the conventional slip control device, the sensor provided for each wheel can detect only the wheel speed of the wheel, and whether the wheel is rotating forward or reverse is detected. The rotation direction cannot be detected, and only the wheel speed is detected (the speed can be detected even in the case of reverse rotation).

For this reason, as shown in FIG. 5, for example, when the vehicle 1 is retreating as shown by an arrow X due to a low μ road on an uphill road 2, the non-driving wheel 3 and the driving wheel 4 Are rotating together, the non-driving wheel 3 is rotating in reverse due to the retreat of the vehicle 1 (in the figure, the rotation of the wheel in the counterclockwise direction is normal rotation), and the driving wheel 4 is driven by the driving force of the engine. It is rotating forward. In this case, as described above, since the wheel speed sensors of the respective wheels can detect only the wheel speed, the outputs are VWR> 0 and VWF> 0.

On the other hand, depending on the inclination angle of the uphill road 2 and the value of μ of the road surface, a case where the driving wheel speed VWR is higher than the non-driving wheel speed VWF (VWR> VWF) may occur. In this case, in the traction control, the control of the drive wheel 4 is executed based on the above equation, and the drive wheel 4 continues to rotate while the drive wheel 4 is still slipping. For this reason, there is a problem that the vehicle 1 retreats in the above-described state even though the driver continues to step on the accelerator. As described above, in order to stop the retreat of the vehicle 1 that has occurred on the low μ uphill road 2, it is necessary to temporarily stop the vehicle 1.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a sensor capable of detecting the rotational direction of each wheel, and brakes the vehicle when the rotational directions of the drive wheels and the non-drive wheels are different. Accordingly, an object of the present invention is to provide a wheel slip control device that improves startability on an uphill road.

[0013]

FIG. 1 is a diagram illustrating the principle of the present invention. As shown in the figure, in order to solve the above problem, in the present invention, a non-driving wheel speed detecting means (A1) for detecting the wheel speed of the non-driving wheel (W1), and the wheel speed of the driving wheel (W2) Driving wheel speed detecting means (A2) to detect, and the non-driving wheel speed detecting means
(A1) and the drive wheel speed detection means (A2) detect each wheel (W1,
W2) detects the occurrence of wheel slip based on the wheel speed
A wheel slip control device comprising wheel slip suppression means (A3) for suppressing wheel slip;
A non-drive wheel rotation direction detecting means (A4) for detecting the wheel rotation direction of (W1); a drive wheel rotation direction detection means (A5) for detecting the wheel rotation direction of the drive wheel (W2); Based on the detection results of the rotation direction detection means (A4) and the drive wheel rotation direction detection means (A5), a slip of a predetermined amount or more occurs in the drive wheel (W2).
The direction of wheel rotation of the non-drive wheel (W1) and the rotation of the drive wheel (W2)
If the wheel rotation direction does not match, the drive wheel (W2)
Apply a braking force to stop the rotation of the drive wheel (W2), and
Braking control means (A6) for stopping the vehicle is provided.

[0014]

In the wheel slip control device having the above structure,
By providing the non-drive wheel rotation direction detection means (A4) and the drive wheel rotation direction detection means (A5), the rotation direction of each wheel can be detected.

[0015] For this reason, since the rotation direction of the non-drive wheel (W1) and the rotation direction of the drive wheel (W2) do not match, it is possible to detect a state in which the vehicle is moving backward on an uphill road.

The braking control means (A6) detects whether or not the rotation direction of the non-drive wheel (W1) and the rotation direction of the drive wheel (W2) are inconsistent. Braking and stopping. As a result, it is possible to prevent the vehicle from moving backward on a low μ uphill road, and to improve startability.

[0017]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram of a main part of a vehicle 10 equipped with a wheel slip control device according to an embodiment of the present invention. In this embodiment, a rear-wheel drive vehicle is taken as an example.

In FIG. 1, reference numeral 12 denotes a right front wheel (non-drive wheel), 13 denotes a left front wheel (non-drive wheel), 14 denotes a right rear wheel (drive wheel), and 15 denotes a left rear wheel (drive wheel). . The driving force of the engine 11 is transmitted to the rear wheels 14 and 15 via a propeller shaft 11a, a differential gear 11b, and the like. A transmission (not shown) is connected to the engine 11, and the transmission is provided with a backlight switch 35 that is closed when a gear is engaged. The backlight signal generated by the backlight switch 35 is transmitted to a slip control computer 21 described later.

The backlight switch 35 functions as a driving wheel rotation direction sensor.
The slip control computer 21 can detect the rotation direction of the drive wheels 14 and 15 based on the backlight signal generated by the computer. Specifically, when the backlight signal is supplied, the slip control computer 21
Determines that the drive wheels 14 and 15 are rotating in the reverse direction, and in a state where the backlight signal is not supplied, the slip control computer 21 determines that the drive wheels 14 and 15 are rotating in the forward direction. In this embodiment, the driving wheel rotation direction sensor is constituted by the backlight switch 35, but a sensor for directly detecting the rotation of the driving wheels 14, 15 is provided similarly to the non-driving wheel rotation direction sensor 33 described later. It is also possible to adopt a configuration in which

Each of the wheels 12 to 15 has a brake 1
6 to 19 are provided, and the respective brakes 16 to 19 are provided.
Are connected to brake pipes 16 a to 19 a connected to an ABS (Anti-lock Breaking System) actuator 20. The ABS actuator 20 controls each brake 16 by a signal from the slip control computer 21.
The brake hydraulic pressure supplied to the brakes 16 to 19 is controlled, thereby controlling the braking force of each of the brakes 16 to 19.

The ABS actuator 20 is connected to a traction control (TRC) actuator 22. The TRC actuator 22 supplies a brake oil pressure to the ABS actuator 20 according to a signal from a slip control computer 21. At this time, a signal is also supplied from the slip control computer 21 to the TRC pump 23, and the TRC pump 23 operates a pump motor to pressure-feed brake fluid to the TRC actuator 22, thereby generating a TRC control hydraulic pressure.

The brake pedal 24 is a brake booster 2
5 is connected to the master cylinder 26, and the pedaling force generated when the driver depresses the brake pedal 24 is amplified by the brake booster 25 and the master cylinder 2
At step 6, it is converted to brake hydraulic pressure. A reservoir tank 27 in which brake fluid is stored is provided above the master cylinder 26. When the TRC pump 23 operates, the reservoir tank 2
The brake fluid stored in 7 is sent to the TRC actuator 22 under pressure to generate TRC control oil pressure.

Further, a stop lamp switch (abbreviated as stop S / W) 28 is provided on the brake pedal 24. The stop S / W 28 is closed when the brake pedal 24 is depressed, and the vehicle 10 A stop lamp (not shown) provided at the rear of the camera is turned on. The switch signal of the stop S / W 28 is also transmitted to the slip control computer 21.

Each of the wheels 12 to 15 has a wheel 2
Wheel speed sensors 29 to 32 for detecting the wheel speeds of No. to No. 5 are provided. The wheel speeds of the wheels 12 to 15 are individually detected by the wheel speed sensors 29 to 32, and the detected wheel speeds are transmitted to the slip control computer 21.

The right front wheel 12 (non-drive wheel) among the wheels 12 to 15 is provided with a rotation direction detection sensor 33 capable of detecting the rotation direction of the wheel. The wheel rotation direction detected by the rotation direction detection sensor 33 is transmitted to the slip control computer 21. In this embodiment, the wheel speed sensors 29 to 32 are connected to the wheels 12 to
Fifteen wheel speeds can be detected, and the rotation direction detection sensor 33 can detect only the rotation direction of the wheels 12. However, it is also possible to use a sensor that can detect both the wheel speed and the rotation direction.

Here, an example of the rotation direction detecting sensor 33 will be described with reference to FIG. In the figure, 40 is the right front wheel 1
2 (non-drive wheels) axle shaft, axle 4
1 is rotatably supported via a bearing 42. The rotation direction detection sensor 33 is generally composed of a slit plate 43 fixed to the axle shaft 40 and an optical sensor unit 44 fixed to the axle 41. The slit plate 43 has a number of slits 43 a formed at equal intervals, and is fixed to the axle shaft 40 by bolts 45. The optical sensor unit 44 includes two photo interrupters 44a and 44b.
The two photointerrupters 44a and 44b are arranged so as to have a phase difference of, for example, 4.5 ° for detecting the rotation direction. Therefore, each of the two photointerrupters 44a, 44b
The rotation direction of the right rear wheel 14 can be detected from the sensor output signal (rotation direction signal) output from the controller.

Returning to FIG. 2, description will be continued. The slip control computer 21 is constituted by a microcomputer, and specifically, an engine control computer (ECU), a TRC computer, and an AB (not shown)
It is composed of an S computer and the like. These computers are connected to each other, and are configured to be able to exchange information.

The ECU receives various signals necessary for engine control, such as a throttle position signal, from various sensors. Based on these sensor signals, the ECU performs fuel injection amount control, ignition control, and the like to drive the engine 11 under optimum conditions. Is what you do. Among the signals transmitted to the ECU, the signals required for the TRC and the ABS are transmitted from the ECU to the TRC computer and the ABS computer.

The ABS computer determines the wheel speeds obtained from the wheel speed signals transmitted from the wheel speed sensors 29 to 32 and the TRC transmitted from the TRC computer.
Based on the control signal, the ABS actuator 20
And outputs a control signal to the TRC actuator 22.
Further, it outputs the wheel speed signal to the TRC computer.

The TRC computer determines the running state and the slip rate based on the wheel speed transmitted from the ABS computer and the throttle position signal transmitted from the ECU, and controls the occurrence of slip (in this embodiment, the brake). 16 to 19).

Each of the above computers includes a microprocessor (MPU), a read only memory (ROM), a random access memory (RAM), a bidirectional bus line for connecting these, and an I / O for connecting to external sensors and devices.
Each is constituted by an O (Input and Output) unit or the like. Further, the slip control process executed when the vehicle 10 which is a main part of the present invention starts on the low μ uphill road 2 is executed by the TRC computer.

The wheel slip suppressing means (A3) and the braking control means (A6) described with reference to FIG. 1 are configured as software programs executed by a slip control computer (TRC computer) 21. Hereinafter, the slip control operation performed by the slip control computer 21 will be described with reference to FIG.

When the processing shown in the figure is started, first in step 10 (step is abbreviated as S in the figure), the slip control computer 21 detects the wheel speed sensors 29 and 30 disposed on the non-driving wheels 12 and 13. The non-driving wheel speed VWF is calculated from the transmitted non-driving wheel speed signals, and the driving wheel speeds are calculated from the driving wheel speed signals transmitted from the wheel speed sensors 31 and 32 disposed on the driving wheels 14 and 15, respectively. The speed VWR is calculated.

In the following step 12, step 1
Based on the non-drive wheel speed VWF and the drive wheel speed VWR calculated at 0, the start of TRC control is determined. Specifically, the non-drive wheel speed VWF is equal to the drive wheel speed VWR.
Is determined to be a small value with respect to.
In step 12, the value obtained by adding a predetermined constant C to the non-drive wheel speed VWF and the drive wheel speed VWR are compared to adjust the TRC control start determination level.

If a negative determination is made in step 12, it means that no slip has occurred or the amount of slip has occurred is small. Since it is not necessary to perform TRC control in such a running state of the vehicle 10,
The process returns to step 10 without performing the TRC control of step 14 and the subsequent steps and the slip control which is a feature of the present invention. On the other hand, if a positive determination is made in step 12 and it is determined that a slip has occurred, the process proceeds to step 14.

In step 14, the slip control computer 21 detects the rotation direction of the non-driving wheels 12, 13 based on the output signal from the non-driving wheel rotation direction sensor 33.
Specifically, when the non-driving wheels 12 and 13 are rotating forward (forward direction), the non-driving wheel rotation direction flag WFH is set to positive (+ WFH), and the non-driving wheels rotate backward (reverse direction). In this case, the non-drive wheel rotation direction flag WFH is set to a negative value (-WFH).

In the following step 16, the slip control computer 21 detects the rotation direction of the drive wheels 14, 15 based on the backlight signal supplied from the back lamp switch 35. Specifically, when the drive wheels 14 and 15 are rotating forward (forward), the drive wheel rotation direction flag W
RH is set to positive (+ WRH), and when the vehicle is rotating backward (reverse direction), the drive wheel rotation direction flag WRH is set to negative (-WRH).

Based on the non-driving wheel rotation direction flag WFH and the driving wheel rotation direction flag WRH determined in steps 14 and 16, in step 18, the non-driving wheels 12,
It is determined whether or not the rotation direction of 13 and the rotation directions of drive wheels 14 and 15 match. Specifically, the non-drive wheel rotation direction flag WFH and the drive wheel rotation direction flag WRH are integrated, and if WFH * WRH ≧ 0, the non-drive wheel 1
It is determined that the rotation directions of the driving wheels 14 and 15 match the rotation directions of the driving wheels 14 and 15. If WFH * WRH <0, the rotation directions of the non-driving wheels 12 and 13 and the driving wheels 14 and 15 are determined.
It is determined that the rotation directions do not match.

The direction of rotation of the non-drive wheels 12, 13 and the drive wheel 1
The case where the rotation directions 4 and 15 coincide with each other is a case where the vehicle 10 is traveling in the direction intended by the driver, which is a normal running state. However, when the rotation directions of the non-drive wheels 12, 13 and the rotation directions of the drive wheels 14, 15 do not match, the vehicle 10 does not proceed in the direction intended by the driver, and the driver continues to step on the accelerator. It is in a state of retreating (slipping down) in spite of the fact that it is moving. As described above, such a slipping state is likely to occur at the time of starting on a low μ uphill road, and once the skid has occurred, it is necessary to stop the vehicle 10.

If an affirmative determination is made in step 18, the process proceeds to step 20, where the driving wheels 14, 15 are driven.
It is determined whether the rotation speed (VWR) of the drive wheels 14, 15 is zero or less based on the output signals of the rotation speed sensors 31, 32 provided in. If a negative determination is made in step 20, the drive wheels 14, 15 are not stopped, and in this case, the process proceeds to step 26.
The slip control computer 21 requests the ABS actuator 20 and the TRC actuator 22 to perform a brake control pressure increasing mode. ABS actuator 20
When the slip control computer 21 requests the brake control pressure increasing mode from the slip control computer 21, the TRC actuator 22 supplies brake fluid to each of the brakes 16 to 19 to increase the brake pressure and brake the vehicle 10.

In the following step 30, the stop line
It is determined whether the stop switch signal from the amplifier switch 28 is on. Stop lamp sui
When the switch 28 is on, the driver
When stepping on. In this state, the driver intends to stop the vehicle 10 and there is no need to perform the braking process by the slip control computer 21. Therefore, the process proceeds to step 40 and performs the normal TRC control. The normal TRC control referred to here means a vehicle detected from the slip rate and the vehicle state based on the slip rate obtained from the rotation speed VWF of the non-drive wheels 12 and 13 and the rotation speed VWR of the drive wheels 14 and 15. When the slip generated at 10 is equal to or more than a predetermined value, the process increases the braking force of the brakes 16 to 19 to reduce the engine torque transmitted to the road surface.

On the other hand, if a negative determination is made in step 30 and it is determined that the driver has not depressed the brake pedal 24, the process proceeds to step 32 in which the wheel speed VWF and the driving speed of the non-driven wheels 12, 13 after braking are determined. The wheel speed VWR of the wheels 14 and 15 is calculated, and the process returns to step 20. Therefore, the processes of steps 26, 30, and 32 are repeatedly executed until it is determined in step 20 that the rotation of the drive wheels 14, 15 is stopped, and the brake control pressure increasing mode is maintained.

On the other hand, if an affirmative determination is made in step 20 and it is determined that the rotation of the drive wheels 14 and 15 has been stopped, the process proceeds to step 22 where the rotation speed sensors 29 and 29 provided on the non-drive wheels 12 and 13 are used. From the output signal of 30, it is determined whether the rotation speed (VWF) of the non-driving wheels 12, 13 is zero or less. In this embodiment, the rotation speed VWF of the non-driving wheels 12 and 13 is regarded as the traveling speed of the vehicle 10 . Therefore, if a negative determination is made in step 22, it is determined that the vehicle 10 is not stopped. In this case, the process proceeds to step 28, where the slip control computer 21
And request the TRC actuator 22 for the brake control holding mode.

When the slip control computer 21 requests the brake control holding mode from the slip control computer 21, the ABS actuator 20 and the TRC actuator 22 perform step 26.
The brake pressure increase that has been performed by the above process is stopped, and the brake pressure at that time is held. When the slip control computer 21 switches the mode from the brake control pressure increasing mode to the brake control holding mode by the process of step 28, the slip control computer 21 performs the processes of steps 30 and 32 to determine whether the stop lamp switch 28 is turned on. And when it is off, the non-drive wheels 12,
The wheel speed VWF of the thirteenth wheel and the wheel speed VWR of the drive wheels 14 and 15 are calculated, and the process returns to the step S20. If an affirmative determination is made in step 30, the process proceeds to step 40 where normal TRC control is performed.

On the other hand, if an affirmative determination is made in step 22, the process proceeds to step 24, and the state in which the vehicle 10 has been stopped by the processes in steps 20 and 22 is maintained for a predetermined time (150 ms in this embodiment). Determine if it is. Here, the reason for determining whether or not the state where the vehicle 10 is stopped is maintained for a predetermined time is based on the rotation speed sensor 2.
This is to prevent erroneous determination due to the relatively low resolution of 9 to 32.

If an affirmative determination is made in step 24, it is determined that the vehicle 10 has definitely stopped, and the process proceeds to step 36, in which the slip control computer 21 sets the ABS actuator 20 and the TRC actuator 2
2 requests the brake control pressure reduction mode. When the slip control computer 21 requests the brake control pressure reduction mode, the ABS actuator 20 and the TRC actuator 22 stop holding the brake pressure performed in the process of step 28 and gradually reduce the brake pressure.

As a result, the braking force generated by each of the brakes 16 to 19 is reduced, the non-driving wheels 12 and 13 can rotate again, and the driving wheels 14 and 15 can transmit the driving torque to the road surface again. Becomes Therefore, the driving wheels 14 and 15 rotate by the driving force of the engine 11 and again the engine 11
Is transmitted to the road surface. Step 3
The state of the vehicle 10 that executes the process 6 is a state in which the vehicle 10 is once stopped, so that the vehicle state is stable even when the vehicle 10 starts on a low μ uphill road, and is capable of restarting. Therefore, by executing the series of processes of steps 18 to 32 and step 36, it is possible to smoothly restart the vehicle on a low-μ slope. In the following step 38, the wheel speed VWF of the non-driven wheels 12, 13 and the wheel speed VWR of the driven wheels 14, 15 after the restart are calculated, and the process returns to step 14.

On the other hand, if a negative determination is made in step 18 described above, that is, if WFH * WRH ≧ 0, the rotational direction WFH of the non-drive wheels 12, 13 and the rotational direction WRH of the drive wheels 14, 15 match. If it is determined that the traveling state of the vehicle 10 is a normal state (a state in which the vehicle 10 does not roll down), the steps from step 20 to step 32 are performed.
The process of temporarily stopping the vehicle 10 is unnecessary. Therefore, if a negative determination is made in step 18, the process proceeds to step 34.

In step 34, it is determined whether or not the condition (VWR ≦ VWF + C) in the above equation is satisfied. Then, if an affirmative determination is made in step 34, the process proceeds to steps 36 and 38 described above, and the ABS actuator 20 and the TRC actuator 22 are set to the brake control depressurizing mode. Processing proceeds to 40 and normal TRC
The control is executed. The reason for performing the process in step 34 is that even if it is determined in step 18 that the rotational direction WFH of the non-drive wheels 12 and 13 and the rotational direction WRH of the drive wheels 14 and 15 match, the drive wheel 14 and 1
When the rotation speed VWR of No. 5 is in a region equal to or lower than the standard for starting the normal TRC control, the brake pressure is gradually reduced in step 36 to prevent the occurrence of a sudden slip. In step 44, the time or the number of times is determined by the counter K, and when a predetermined time or number of times has elapsed, the normal TRC control is executed.

Then, in step 40, the normal TR
C control is executed, and it is determined in step 42 whether or not the end condition of the normal TRC control is satisfied. If it is determined that the end condition is not satisfied, the process returns to step 14, and the process returns to step 14. The processing after step 14 is executed again. On the other hand, when it is determined in step 42 that the end condition of the normal TRC control is satisfied, the present control process is ended and the control returns to the normal brake control in which the braking is performed only by the driver's brake operation. did.

[0052]

[0053]

As described above, according to the present invention, the provision of the non-driving wheel rotational direction detecting means and the driving wheel rotational direction detecting means makes it possible to detect the rotational direction of each wheel. Since the rotational direction of the wheels does not match the rotational direction of the drive wheels, it is possible to detect a state in which the vehicle is moving backward on an uphill road.

Therefore, the braking control means detects whether or not the rotation direction of the non-drive wheel and the rotation direction of the drive wheel do not match, and if it is determined from the detection result that the rotation direction does not match, brakes and stops the vehicle. As a result, it is possible to prevent the vehicle from retreating on a low μ uphill road and to improve startability.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a main part configuration diagram of a vehicle equipped with a wheel slip control device according to one embodiment of the present invention.

FIG. 3 is a diagram illustrating a structure of an example of a rotation direction sensor.

FIG. 4 is a flowchart showing a slip control operation executed by a slip control computer.

FIG. 5 is a diagram for explaining a rotation state of wheels when the vehicle retreats on a low μ uphill road.

[Explanation of symbols]

10 vehicle 11 engine 12-15 wheels (12,13 → non-drive wheels: 14,15
→ Drive wheel 16-19 Brake 20 ABS actuator 21 Slip control computer 22 TRC actuator 23 TRC pump 24 Brake pedal 28 Stop lamp switch 29-32 Wheel speed sensor (29, 30 → Non-drive wheel:
31, 32 → drive wheel) 33 rotation direction sensor 35 backlight switch 43 slit plate 43a slit 44 optical sensor unit 44a, 44b photo interrupter

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60T 8/58

Claims (1)

(57) [Claims] 1. A non-driving wheel speed detecting means for detecting a wheel speed of a non-driving wheel, a driving wheel speed detecting means for detecting a wheel speed of a driving wheel, a non-driving wheel speed detecting means and a driving wheel speed detecting means A wheel slip control device that detects the occurrence of a wheel slip based on the wheel speed of each wheel detected by the wheel slip control device and that suppresses the wheel slip. A wheel rotation direction detection unit, a drive wheel rotation direction detection unit that detects a wheel rotation direction of a drive wheel, a predetermined rotation of the drive wheel based on detection results of the non-drive wheel rotation direction detection unit and the drive wheel rotation direction detection unit. Pickpocket
And the direction of wheel rotation of the non-driven wheel and the drive
If the rotation direction of the wheels does not match,
The braking force is applied to stop the rotation of the drive wheels, and the vehicle
And a braking control means for stopping the vehicle.