JPH0585342A - Slip control device for vehicle - Google Patents

Abstract

PURPOSE:To detect the abnormality of wheel speed sensors positively even at the time of two wheel speed sensors becoming abnormal simultaneously so as to enable the stop of slip control by providing a control stop means for stopping slip control when the abnormality of the wheel speed sensors is detected by a sensor abnormality detecting means for judging the wheel speed sensors without output signals to be abnormal. CONSTITUTION:There is provided a vehicle travel judging means 131 for detecting the continuous state, for the fixed time, of the maximum wheel speed among plural wheel speeds being the specified value or more and the rate-of- change of the maximum wheel speed being in a specified range or less in order to judge the travel state of a vehicle. When the vehicle is judged to be in the traveling state by this vehicle travel judging means 131, wheel speed sensors 112FL-112RR without output signals are judged to be abnormal by a sensor abnormality detecting means 132. When the abnormality of these wheel speed sensors 112FL-112RR is detected by the abnormality detecting means 132, slip control is stopped by a control stop means 133.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle slip control device, and more particularly to a technique for detecting an abnormality of a wheel speed sensor used for the slip control.

[0002]

2. Description of the Related Art Conventionally, for example, an anti-skid brake device and a traction control device have been known as this type of vehicle slip control device. The anti-skid brake device controls the brake hydraulic pressure of the vehicle to adjust the braking force of each wheel to prevent the wheel from being locked or skid during braking. On the other hand, the traction control device detects the slip amount of the drive wheels in order to prevent the drive wheels from slipping due to excessive drive torque and causing a drive loss when the vehicle accelerates, and the acceleration performance is reduced. The brake fluid pressure applied to the drive wheels and the engine output are controlled so that the slip amount of the drive wheels becomes the target slip amount corresponding to the friction coefficient of the road surface (the braking force is applied to the drive wheels or the engine output is reduced. To let).

In such a slip control device,
Since it is necessary to detect the rotation speed (wheel speed) of each wheel, an electromagnetic pickup type wheel speed sensor is provided for each wheel for that purpose. When the wheel speed sensor for detecting the wheel speed has an abnormality such as a failure or a wire breakage, the anti-skid brake control and the traction control are unstable.
In the technique disclosed in Japanese Patent No. 087, the anti-skid brake control is stopped when an abnormality occurs in the output signal of the wheel speed sensor.

[0004]

In the case of detecting an abnormality of the wheel speed sensor as described above, when one wheel speed sensor is in an abnormal state, the output signals of the other remaining wheel speed sensors can be observed. , It is possible to identify and determine whether or not the wheel speed sensor is abnormal.

However, when the two wheel speed sensors are in an abnormal state at the same time, it cannot be dealt with. For example, when the parts around the suspension are serviced by inspecting or replacing parts at the time of shipment from the manufacturing plant, an abnormal state may occur due to erroneous assembly of the wheel speed sensor or missing parts. Although rare, it is possible that the two wheel speed sensors may be damaged at the same time by flying stones during running. In order to take measures against these, even if the two wheel speed sensors are abnormal, It needs to be detected reliably.

The present invention has been made in view of the above points, and an object thereof is to improve the abnormality detection mode of a wheel speed sensor to ensure that two wheel speed sensors become abnormal at the same time. To be able to detect.

[0007]

In order to achieve the above object, according to the invention of claim 1, one of the wheels having the highest rotation speed is used.
The stable running state of the vehicle is detected based on the rotation speed of the two wheels and the degree of change thereof, and when the vehicle is in the stable running state, the vehicle speed sensor having no output signal is determined to be abnormal.

Specifically, in the present invention, as shown in FIG. 1, wheel speed sensors 112FL to 112RR for detecting the rotational speeds of the wheels 7FL to 7RR are provided, and the wheels detected by the wheel speed sensors 112FL to 112RR. In the slip control device for performing the slip control based on the speed, a state in which the maximum wheel speed among the plurality of wheel speeds is a predetermined value or more, and the change rate of the maximum wheel speed is within a predetermined range for a certain period of time. A vehicle traveling determination means 131 for determining the traveling state of the vehicle by detecting continuation, and a wheel speed sensor having no output signal when the vehicle traveling determination means 131 determines that the vehicle is traveling. 112FL ~ 112
A sensor abnormality detecting means 132 for determining RR as an abnormality, and a wheel speed sensor 112 by this sensor abnormality detecting means 132.
Control stop means 133 for stopping the slip control when an abnormality of FL to 112RR is detected is provided.

According to the second aspect of the invention, the stable running state of the vehicle is detected based on two arbitrary wheel speeds.

That is, according to the present invention, in the above slip control device, any two wheel speeds among a plurality of wheel speeds are equal to or higher than a predetermined value, and the difference between the two wheel speeds is within a predetermined range. Is detected to determine the traveling state of the vehicle, and when the vehicle traveling determination means 131 'determines that the vehicle is traveling,
A sensor abnormality detecting unit 132 that determines that the wheel speed sensors 112FL to 112RR having no output signal are abnormal, and the wheel abnormality sensors 112FL to 112FL to 112FL to
A control stop means 133 for stopping the slip control when an abnormality of 112RR is detected is provided.

According to the third aspect of the present invention, the acceleration state or the deceleration state of the vehicle is detected, and when the output signal of the wheel speed sensor suddenly changes in that state, the wheel speed sensor is judged to be in an abnormal state.

That is, in the present invention, in the above slip control device, the difference between any two wheel speeds among a plurality of wheel speeds is within a predetermined range, and both wheel speeds change by a predetermined value or more. When the vehicle acceleration / deceleration determining means 134 determines that the vehicle is in an acceleration / deceleration state, the wheel speed signal is detected. Other than the wheel speed sensors 112FL to 112RR for outputting the wheel speed sensor 112FL to 112RR and the wheel speed sensor 112FL to 112RR whose wheel speed signal has suddenly changed are determined to be abnormal. 112F
Control stop means 133 for stopping the slip control when an abnormality of L to 112RR is detected is provided.

According to the invention of claim 4, in the slip control device according to claim 3, the sensor abnormality detecting means 132 '.
Is a wheel speed sensor 112FL to 112RR other than the wheel speed sensors 112FL to 112RR that output a wheel speed signal when the vehicle acceleration / deceleration judging means 134 judges the acceleration state of the vehicle. Is determined to be abnormal.

[0014]

With the above structure, in the invention of claim 1, the vehicle traveling determination means 131 causes the maximum wheel speed of the plurality of wheel speeds to be a predetermined value or more and the rate of change of the maximum wheel speed to be a predetermined range or less. When it is detected that the state of (1) continues for a certain period of time, it is determined that the vehicle is traveling stably at that time. That is, the maximum wheel speed becomes equal to or higher than the predetermined value even when the wheels 7FL to 7RR are rotated in a no-load state by jacking up, but at that time, the wheel speed suddenly changes in a short time. Therefore, at the same time, it is determined that the vehicle is traveling stably by eliminating the situation such as jack-up by observing that the rate of change of the maximum wheel speed is within the predetermined range for a certain period of time. be able to. In the stable running state of this vehicle, the wheel speed sensors 112FL to 112FL-1
If the 12RR is normal, a signal is output from it, so the wheel speed sensor 112F without this output signal is output.
The sensor abnormality detection unit 132 determines that L to 112RR are abnormal, and the control suspension unit 133 suspends the slip control. In this way, the vehicle traveling state is determined based on one maximum wheel speed and the sensor abnormality during traveling is detected. Therefore, even if the two wheel speed sensors 112FL to 112RR simultaneously become abnormal, it is possible to reliably detect that. The slip control can be stopped. As a result, it is possible to prevent the slip control from being continued unsteadily.

According to the second aspect of the invention, the vehicle traveling determination means 1
When it is detected by 31 'that two arbitrary wheel speeds are equal to or higher than a predetermined value and the difference between the two wheel speeds is within a predetermined range, it is determined that the vehicle is traveling stably at that time. .. That is, for example, by jacking up the wheels 7FL to
In the state in which the 7RR is rotated, one driving wheel is stopped and only the other driving wheel is rotated due to variations in bearings and the like, even though there is no load. Therefore, any 2
It is possible to determine that the two wheels rotate at a predetermined value or more and the difference between the two wheel speeds is within a predetermined range, not under a situation such as a jack-up but in a situation where the vehicle is traveling stably. it can. While the vehicle is traveling stably, the wheel speed sensors 112FL to 112RR having no output signal are determined to be abnormal by the sensor abnormality detecting unit 132, and the slip canceling control is stopped by the control stopping unit 133. In the present invention, although the two wheel speed signals are required, the abnormality determination can be performed in a short time.

According to the third aspect of the invention, the acceleration / deceleration determination means 13
4, the difference between any two wheel speeds is within a predetermined range,
In addition, it is determined that the vehicle is in the acceleration / deceleration state by detecting that the speeds of both wheels have changed by a predetermined value or more. That is,
If the difference between any two wheel speeds is within a predetermined range, it is determined that the vehicle is in the traveling state for the above-mentioned reason, and both wheel speeds are changing by a predetermined value or more, so that the vehicle is in an acceleration / deceleration state. .. In the wheel speed sensors 112FL to 112RR,
A predetermined gap is set between a portion that rotates together with the wheels 7FL to 7RR and a detection portion that electrically detects the rotation, and if the gap becomes large due to some abnormality, an output signal is output at a certain rotation speed. Has a characteristic that changes rapidly. Therefore, when the vehicle acceleration / deceleration determining means 134 determines that the vehicle is in the acceleration / deceleration state, the output signals of the wheel speed sensors 112FL to 112RR other than the wheel speed sensors 112FL to 112RR used for the determination suddenly change due to the above characteristics. When the wheel speed sensor 112FL ~
112RR can be determined to be abnormal. Even in this case, the slip control is stopped by the control stopping unit 133.

In the invention of claim 4, the acceleration / deceleration determining means 13
When the acceleration state of the vehicle is determined by 4, the wheel speed sensors 112FL to 112RR whose wheel speed signals have rapidly increased are determined to be abnormal, and the slip control is stopped. Claim 3
In the slip control device of No. 1, when detecting during deceleration of the vehicle, the wheel speed sensor 1 is locked by locking the wheels 7FL to 7RR.
The output signals of 12FL to 112RR may decrease sharply and may be erroneously determined. However, by determining the abnormality of the wheel speed sensors 112FL to 112RR during the acceleration of the vehicle in this way, the above erroneous determination occurs. There is no room to detect a sensor abnormality with certainty.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1) In the vehicle shown in FIG.
Is an engine, and 3 is an automatic transmission connected to the engine 1 via a torque converter 2. 7FL and 7FR are left and right front wheels, and 7RL and 7RR are left and right rear wheels. In this vehicle, the left and right rear wheels 7RL and 7RR are the engine 1, the automatic transmission 3, the propeller shaft 4, the differential device 5, and the left and right axles. Drive wheels are driven via 6L and 6R, and left and right front wheels 7FL and 7FR are driven wheels and steered wheels.

The automatic transmission 3 is a multi-step transmission gear mechanism 3a.
Is equipped with. The speed change gear mechanism 3a is of a hydraulically actuated type as is known, and for example, in the embodiment, it is for four forward gears and one reverse gear. That is, shifting is performed by changing the combination of excitation and demagnetization of the plurality of solenoids 39a, 39a, ... Incorporated in the hydraulic circuit. Further, the torque converter 2 has a hydraulically operated lockup clutch 2a, and by switching between excitation and demagnetization of a solenoid 39b incorporated in the hydraulic circuit,
Signing and unbinding is performed.

The solenoids 39a and 39b are controlled by the AT controller 101 for controlling the shift of the automatic transmission 3. The AT controller 101 stores the shift characteristic and the lockup characteristic in advance, and performs the shift control and the lockup control based on this. Therefore, A
The T controller 101 includes throttle opening signals from a main throttle opening sensor 102 for detecting the opening of the main throttle valve 10 in the intake passage 8 and a sub throttle opening sensor 103 for detecting the opening of the sub throttle valve 12. And a vehicle speed signal (a rotation speed signal of the propeller shaft 4 in the embodiment) from the vehicle speed sensor 104 for detecting the vehicle speed.

The wheels 7FL to 7RR are provided with brakes 21FL to 21RR, respectively. Calipers 22FL to 22RR of the brakes 21FL to 21RR
Brake piping 23F for each (wheel cylinder)
Brake fluid pressure is supplied via L-23RR.
The structure for supplying the brake fluid pressure is as follows. First, the depression force of the brake pedal 25 is boosted by a hydraulic booster 26 and transmitted to a tandem master cylinder 27. The master cylinder 2
Brake pipe 23 for the left front wheel is provided at the first outlet 27a of No. 7
The FL is connected to the second outlet 27b, and the brake pipe 23FR for the right front wheel is connected to the second outlet 27b.

The brake pipe 23FL for the left front wheel and the brake pipe 23FR for the right front wheel are provided with electromagnetic on-off valves 40A and 41A, respectively, and a relief connected downstream of the on-off valves 40A and 41A. Passage 42
Electromagnetic on-off valves 40B and 41B are provided on L and 42R, respectively.
Is installed.

A hydraulic pressure from a pump 29 is supplied to the booster 26 via a pipe 28, and an excess hydraulic pressure is returned to a reservoir tank 31 via a return pipe 30. A branch pipe 28a branched from the pipe 28 is connected to the merging portion a, and an electromagnetic opening / closing valve 32 is provided in the branch pipe 28a. The booster hydraulic pressure generated by the booster 26 is supplied to the merging portion a through a pipe 33, and the pipe 33 also has an electromagnetic opening / closing valve 34.
Is installed. A one-way valve 35 that allows only the flow toward the merging portion a is provided in the pipe 33 in parallel with the opening / closing valve 34.

Brake pipes 23RL and 23RR for the left and right rear wheels are connected to the merging portion a. This piping 23
RL and 23RR are electromagnetic on-off valves 36A and 3R, respectively.
7A is interposed and the on-off valves 36A, 37
Electromagnetic on-off valves 36B and 37B are connected to the relief passages 38L and 38R connected downstream of A, respectively.

Each of the on-off valves 32, 34, 36A, 36
B, 37A, 37B, 40A, 40B, 41A, 41B
Are controlled by the controller 111. This controller 111 has a built-in microcomputer and is for performing anti-skid brake control and traction control. It should be noted that the controller 111 is not shown separately for anti-skid brake control and traction control, but the control content is different for each.

In this case, when the traction control (brake control) is not performed, the open / close valve 32 is closed, the open / close valve 34 is opened, the open / close valves 36B and 37B are closed, and the open / close valves 36A and 37A are opened as shown in the figure. Be done. This allows
When the brake pedal 25 is depressed, brake fluid pressure is supplied to the front wheel brakes 21FL and 21FR via the master cylinder 27. Further, to the rear wheel brakes 21RL and 21RR, a boosting hydraulic pressure corresponding to the stepping force of the brake pedal 25 from the hydraulic boosting device 26 is supplied as a brake hydraulic pressure via a pipe 33.

As will be described later, the opening / closing valve 34 is closed and the opening / closing valve 32 is opened when the traction control is performed. Further, the on-off valves 36A, 36B, 37A, 37
B, 40A, 41A, 40B and 41B are controlled to be opened and closed by duty control. In addition, the branch pipe 28
The brake fluid pressure that has passed through a does not act as a reaction force to the brake pedal 25 due to the action of the one-way valve 35.

In the case of traction control, drive wheels 7RL,
In order to reduce the drive torque of 7RR, drive wheels 7RL,
Brake control for 7RR and drive wheel 7
The driving force transmitted to the RL and 7RR, that is, the torque generated by the engine 1 is also reduced. Therefore, in the intake passage 8 of the engine 1, the main throttle valve 10 connected to the accelerator pedal 9 and the sub-throttle valve 12 connected to the throttle opening adjustment actuator 11 are arranged. The valve 12 is controlled by the controller 111 for controlling the traction via the actuator 11.

Next, the anti-skid brake control and the traction control will be described in detail. First, the anti-skid brake control will be described. In this embodiment, the left front wheel 7FL is operated by operating the opening / closing valves 40A and 40B.
The first channel for adjusting the braking pressure of the brake 21FL and the operation of the opening / closing valves 41A and 41B cause the right front wheel 7FR to operate.
Brake 21FR of the right and left rear wheels 7RL, 7RR of the second channel for adjusting the braking pressure and the operation of the on-off valves 36A, 36B, 37A, 37B.
A third channel for adjusting the braking pressure of 1RR is provided, and these channels are controlled independently of each other.

The controller 111 for controlling the above-mentioned first to third channels outputs the brake signal from the brake sensor 115 for detecting whether or not the brake pedal 25 is depressed and the rotation speed V of each wheel 7FL to 7RR. The wheel speed signals from the wheel speed sensors 112FL to 112RR to be detected and the turning angle signal from the steering angle sensor 114 are input, and anti-skid brake control is performed in parallel for each channel.

The control contents will be described in detail. The controller 111 includes a pseudo vehicle body speed setting unit and a control threshold value setting unit, and compares the control threshold value with the wheel acceleration / deceleration and the slip ratio to perform phase 0 (anti-skid brake). Non-controlled state), Phase I (state of braking pressure reduction during anti-skid brake control), Phase II (state of holding after decompression), Phase III (state of rapid pressure increase after pressure reduction hold) and Phase IV (state of sudden pressure increase A phase is selected from (slow pressure increase state), and a braking pressure control signal corresponding to each phase is output to the opening / closing valves 36A, 36B, 37A, 37B, 40A, 40.
B, 41A and 41B are output.

The pseudo vehicle speed Vr is set as a convenient vehicle speed based on the wheel speed, and the highest wheel speed of the four wheels 7FL to 7RR is set as the pseudo vehicle speed Vr. On the other hand, the amount of speed change depends on the friction coefficient of the road surface, from 1.2 G · Δt at high friction coefficient to 0 at low friction coefficient.
It is set up to 3 G · Δt and corrected as follows.
In addition, Δt is a sampling cycle (for example, 7 ms).

Vr ← Vr− (1.2 G · Δt to 0.3 G · Δt) The control threshold is set independently for each channel, and in the case of the present embodiment, the control threshold is the phase 0 described above. The first wheel deceleration threshold G1 for determining the transition from (when the anti-skid brake is not controlled) to Phase I (pressure reduction)
And the second wheel deceleration threshold G2 for determining the transition from phase I to phase II (hold), and phase II to phase II
First slip ratio threshold S1 for determining transition to I (rapid pressure increase)
And the wheel acceleration threshold value G3 for determining the transition from phase III to phase IV (slow pressure increase), and phase IV to phase I
There is a second slip ratio threshold S2 for determining the shift to. The control threshold is appropriately set according to the pseudo vehicle body speed Vr and the friction coefficient of the road surface.

Regarding the wheel speeds of the rear wheels 7RL and 7RR,
The smaller wheel speed of the two wheel speeds is selected as the rear wheel speed. Further, the slip ratio is calculated according to the following equation.

Slip ratio = (1-wheel speed ÷ pseudo vehicle speed) × 100 As shown in FIG. 6, the setting of the control threshold value is performed on the road surface without excessively lowering the lateral resistance coefficient μL of the wheel with respect to the road surface. It is set so that the friction coefficient μ with the wheel can be increased, that is, a characteristic in the range of Ss can be obtained.

The deceleration and acceleration of the wheel are obtained by dividing the difference between the previous value and the present value of the wheel speed by the sampling cycle Δt and converting the result into the gravitational acceleration. Therefore, normally, the increase / decrease control of the braking pressure as shown in FIG. 7 is performed. That is, when the brake pedal 25 is depressed from the constant speed running state, the braking pressure increases and the wheel speed decreases accordingly.

When the wheel deceleration becomes larger than the first wheel deceleration threshold value G1, the control shifts to the anti-skid brake control, the phase I is selected, and the braking pressure is reduced according to a predetermined pressure reducing mode.

When the wheel deceleration becomes smaller than the second wheel deceleration threshold G2, the phase II is selected and the braking pressure is maintained in the reduced pressure state.

When the slip ratio decreases as the pressure is maintained and exceeds the first slip ratio threshold S1, phase III
Is selected, and the braking pressure is rapidly increased.

When the wheel acceleration decreases due to the sudden pressure increase and becomes equal to or lower than the wheel acceleration threshold G3, the phase IV is selected and the braking pressure is gradually increased.

Due to the above-mentioned gentle pressure increase, the slip ratio becomes the second value.
Phase I is selected when the slip ratio threshold S2 is exceeded.

As described above, the braking pressures of the first to third channels are controlled independently of each other to prevent the wheels from being locked or skided, thereby improving the directional stability. It will stop the vehicle for a short braking distance without losing it.

At the time of traction control, brake control, engine control by controlling the throttle opening adjustment actuator 11 and AT for gear shift control are performed.
Lockup control is performed via the controller 101. The controller 111 includes a throttle opening sensor 1
02, 103 and the signals from the vehicle speed sensor 104, the wheel speed signals from the wheel speed sensors 112FL to 112RR for detecting the speed V of the wheels 7FL to 7RR,
An accelerator opening signal from an accelerator opening sensor 113 that detects an accelerator opening, a steering wheel steering angle signal from a steering angle sensor 114 that detects a steering wheel steering angle, and a mode signal from a manually operated switch 116 are input. To be done.

FIG. 8 shows the content of the traction control by the controller 111, focusing on the engine control and the brake control. In the figure, the target value for the engine (the target slip value of the driving wheels) is indicated by SET, and the target value for the brake is indicated by SET (SBT> SE).
T).

Before time t1, no significant slip has occurred in the drive wheels, so engine control is not performed. Therefore, the sub-throttle valve 12 is fully open and the throttle opening Tn (both throttle valves 10, 12 which is the combined opening of 12 and corresponds to the opening of the throttle valve with the smaller opening) is the main throttle opening TH · M corresponding to the accelerator opening.

At time t1, the slip value of the drive wheels reaches the engine target value SET and a large slip occurs. In the embodiment, the traction control is started when the slip value of the drive wheels becomes equal to or higher than SET, and at this time t1, the throttle opening is reduced to the lower limit control value SM at once ( Feedforward control). Then, after the SM is once set, the opening degree of the sub-throttle valve 12 is feedback-controlled so that the slip value of the drive wheels becomes the engine target value SET. At this time, the throttle opening Tn is equal to the sub-throttle valve opening TH.
It becomes S.

At time t2, the slip value of the drive wheels becomes equal to or higher than the brake target value SBT. At this time, the brake fluid pressure is supplied to the brakes 21RL and 21RR of the drive wheels to control the engine and the brakes. Traction control is initiated by both control. The brake fluid pressure is feedback-controlled so that the slip value of the drive wheel becomes the brake target value SBT.

At time t3, the slip value of the drive wheels becomes less than the braking target value SBT, whereby the brake fluid pressure is gradually reduced, and eventually the brake fluid pressure becomes zero. However, the slip control by the engine is still continued.

The condition for ending the traction control is that the accelerator opening is fully closed in the embodiment.

The slip value of the driving wheel is measured by the wheel speed sensor 11
It is detected based on the detection signals from 2FR to 112RL. That is, the slip value is calculated by subtracting the rotational speed of the driven wheels from the rotational speed of the driving wheels.
When calculating the slip value, in the case of engine control, the larger one of the left and right drive wheels is selected as the rotation speed of the drive wheels, and the average value of the left and right driven wheels is used as the rotation speed of the driven wheels. In the case of brake control, the rotation speed of the driven wheels is the same as that of engine control, but the rotation speed of the drive wheels is the rotation speed of the left and right drive wheels when controlling the braking force on the left and right drive wheels independently of each other. Are used respectively.

FIG. 9 is a block diagram showing a circuit for determining the above target values SET and SBT. The determination parameters are vehicle speed, accelerator opening, steering wheel steering angle,
It includes the operating state of the mode switch 116 and the maximum friction coefficient μmax of the road surface.

That is, in the figure, the basic value STA0 of SET and the basic value STB0 of SBT are stored in the map 121 with the maximum friction coefficient as a parameter (S
TB0> STA0). Then, this basic value STB0, S
By multiplying TA0 by the correction gain coefficient KD, SET and SBT can be obtained.

The correction gain coefficient KD is obtained by multiplying the gain coefficients VG, ACPG, STRG and MODEG. The gain coefficient VG uses the vehicle speed as a parameter and is stored as the map 122. The gain coefficient ACPG has the accelerator opening as a parameter and is stored as the map 123.
The gain coefficient STRG uses the steering angle of the steering wheel as a parameter, and is stored as the map 124. The gain coefficient MODEG is manually selected by the driver and is stored in the table 125. This table 1
In 25, three types of sports mode, normal mode and safety mode are provided.

Each wheel speed sensor 112FL to 112R
R is an electromagnetic pickup coil type. That is, the wheel speed sensors 112FL to 112R
As shown in FIG. 3, the R includes a rotor 51 made of a disk that is attached to wheels 7FL to 7RR so as to rotate integrally therewith, and a plurality of protrusions 51a, 5 are provided on the outer peripheral edge of the rotor 51.
1a, ... Are formed at equal angular intervals. On the vehicle body near the rotor 51, a pole 52 is arranged and fixed so that its tip has a predetermined gap 1 with respect to each projection 51a of the rotor 51. The pole 52 is connected to a magnet (not shown), and the pole 52 is connected by a magnet. A magnetic field is created in the.
A pickup coil 53 is wound around the outer circumference of the pole 52, and when the protrusion 51a comes in contact with or separates from the tip of the pole 52 by the rotation of the rotor 51 integrated with the wheels 7FL to 7RR, a pulsed output voltage is applied to the pickup coil 53. It is supposed to be generated.

Each wheel speed sensor 112FL to 112R
If there is an abnormality in R for some reason, the above-mentioned anti-skid brake control and traction control cannot be performed accurately. This wheel speed sensor 112FL to 112RR
In order to cope with the above abnormality, the controller 111 performs the control shown in FIG. That is, in step S1, the wheel speeds V, V, ... Are read from the output signals of the wheel speed sensors 112FL to 112RR, and in the next step S2, the highest wheel among the read four wheel speeds V, V ,. The speed Vmax is selected and it is determined whether or not the speed Vmax is a predetermined value (for example, a value corresponding to a vehicle speed of 5 km / H). When this determination is NO, the routine proceeds to step S7, where antiskid brake control and traction control are performed as usual. Judgment is Y
In the case of ES, the process proceeds to step S3, and it is determined whether or not the rate of change of the maximum wheel speed Vmax is within a predetermined range (for example, ± 0.5 G). If the determination is NO, the process proceeds to step S7, but if the determination is YES, step S4
Then, it is determined whether the state where the rate of change of the maximum wheel speed Vmax is within a predetermined range has continued for a predetermined time (for example, 0.5 seconds). When this judgment is NO, the routine proceeds to step S7. When the determination is YES, it is considered that the vehicle is in a stable traveling state, and the process proceeds to step S5 to determine whether there are wheel speed sensors 112FL to 112RR having no output signal. This determination is NO, that is, the wheel speed sensors 112FL to 112RR when the vehicle is traveling.
If any of the signals is output from step S7, the process proceeds to step S7, but if YES, that is, if no signal is output from the predetermined wheel speed sensors 112FL to 112RR even when the vehicle is running, that signal is output. The missing wheel speed sensors 112FL to 112RR are considered to be in an abnormal state, and the anti-skid brake control and traction control are stopped in step S6.

In this embodiment, step S in the above flow is performed.
2 to S4, four wheel speed sensors 112FL-11
Maximum wheel speed V among the wheel speeds detected by 2RR
Vehicle running determination means 131 for determining that the vehicle is in a running state by detecting that max is not less than a predetermined value and the rate of change of the maximum wheel speed Vmax is not more than a predetermined range for a certain period of time. Is configured.

Further, when the vehicle traveling determination means 131 determines in step S5 that the vehicle is traveling, the wheel speed sensors 112FL to 112FL having no output signal are output.
A sensor abnormality detection unit 132 that determines RR as abnormal is configured.

Further, in step S6, the wheel speed sensors 112FL to 112FL-1 are detected by the sensor abnormality detecting means 132.
A control suspending unit 133 is configured to suspend the anti-skid brake control and the traction control when an abnormality of 12RR is detected.

Therefore, in this embodiment, the wheel speeds V, V, ... Are detected by the signals from the four wheel speed sensors 112FL to 112RR, and the maximum wheel speed Vmax among the wheel speeds is equal to or higher than a predetermined value. Is determined. This condition occurs, for example, even when the wheels 7FL to 7RR are rotated in a no-load state by jacking up. Therefore, in order to eliminate this condition, the state in which the rate of change of the maximum wheel speed Vmax is within a predetermined range is fixed time. It is determined whether it is continuing. In the jack-up state, since there is no load, the wheel speed increases and decreases in a short time and its fluctuation is large, and the wheel speed is not included in the determination criteria. Therefore, the maximum wheel speed Vma
If it is detected that the rate of change of x is within the predetermined range for a certain period of time, it is determined that the vehicle is traveling stably at that time. Since the wheels 7FL to 7RR are rotating during the stable running of the vehicle, the wheel speed sensor 11
If 2FL to 112RR are normal, a signal is output. Therefore, the wheel speed sensor 112FL having no output signal
It is possible to determine that ~ 112RR is abnormal, and when the sensor is abnormal, the anti-skid brake control and the traction control are stopped.

In this way, the vehicle running state is determined based on one maximum wheel speed Vmax and the sensor abnormality is detected.
Even if the two wheel speed sensors are abnormal at the same time, they can be detected reliably, and the anti-skid brake control and traction control can be stopped.

(Embodiment 2) FIG. 10 shows Embodiment 2 of the present invention, in which the method of determining the running state of the vehicle is changed. In this embodiment, only the control procedure in the controller 111 is different, and the others are the same as in the first embodiment. That is, as shown in FIG. 10, in step S1, the output signals of the wheel speed sensors 112FL to 112RR are read, and in the next step S2 ', any two wheel speeds among the four wheel speeds V, V ,. V1 and V2 are selected, and it is determined whether or not they are equal to or greater than a predetermined value (for example, a value corresponding to a vehicle speed of 5 km / H). When this determination is NO, the routine proceeds to step S7, where antiskid brake control and traction control are performed as usual. If the determination is YES, step S
Proceeding to 3 ', it is judged whether the difference between the two wheel speeds V1 and V2 is within a predetermined range. When this determination is NO, the routine proceeds to step S7, but when the determination is YES, it is considered that the vehicle is in a stable running state, and the routine proceeds to step S5 and the wheel speed sensors 112FL to 112FL without output signals.
Determine if there is an RR. When this determination is NO, the process proceeds to step S7, but when YES, that is, when no signal is output from the wheel speed sensors 112FL to 112RR, the wheel speed sensor 112F having no signal is output.
L-112RR is regarded as an abnormal state, and the anti-skid brake control and traction control are stopped in step S6.

In this embodiment, step S in the above flow is performed.
By 2 ', S3', any two wheel speeds V1, V2 of the four wheel speeds are equal to or more than a predetermined value and both wheel speeds V1, V2,
By detecting that the difference of V2 is within the predetermined range,
A vehicle traveling determination means 131 'for determining that the vehicle is in a traveling state is configured.

Generally, for example, by jacking up the wheels 7
In the state in which the FL to 7RR are rotated, one driving wheel is stopped and only the other driving wheel is rotated due to variations in the bearings and the like, even though there is no load. Therefore, in the second embodiment, it is not a condition such as jack-up that the two arbitrary wheels rotate at a predetermined value or more and the difference between the wheel speeds V1 and V2 of the two wheels is within the predetermined range. It can be determined that the vehicle is traveling stably. Then, as in the case of the first embodiment, the wheel speed sensors 112FL to 112RR having no output signal during stable running of the vehicle.
Is determined to be abnormal, and when the sensor is abnormal, anti-skid brake control and traction control are stopped. In the case of the second embodiment, two wheel speed signals are required instead of one wheel speed signal as in the first embodiment, but on the other hand, the abnormality determination of the sensors 112FL to 112RR can be performed in a short time. ..

(Third Embodiment) FIG. 11 shows a third embodiment in which a predetermined abnormal state of the wheel speed sensors 112FL to 112RR is detected. That is, as shown in FIG. 3, each of the wheel speed sensors 112FL to 112RR is a kind of generator, and the voltage level of the output signal increases as the rotation speed of the rotor 51 increases, and the controller 111
The magnitude of the signal voltage level is compared with a predetermined threshold value, and the rotation speed is determined by the amount exceeding the threshold value. When the gap 1 between each projection 51a on the outer periphery of the rotor 51 and the tip of the pole 52 is proper, the voltage level of the output signal surely exceeds the threshold value even at a low wheel speed, and therefore, as shown by the solid line in FIG. When the rotation speed of 7FL to 7RR increases (during acceleration), the wheel speed V detected by the controller 111 increases proportionally with the passage of time. However, when the gap l between the pole 53 and the rotor projection 51a is increased due to damage or the like,
Since the power generation capacity decreases, the voltage level does not reach the threshold value even though the wheels 7FL to 7RR are actually rotating, and the wheel speed V is V = 0 in the controller 111 as shown by the broken line in FIG. When the signal voltage level exceeds the threshold value due to the increase in the wheel speed V, the controller 111 determines that the wheel speed V is a high speed for the first time, and the wheel speed V is detected as if it suddenly increased. .. The same happens when the vehicle decelerates, and at this time, on the contrary, it is detected that the wheel speed V sharply decreases with the passage of time.

In this embodiment, the above-mentioned characteristics are utilized to detect the abnormal state of the wheel speed sensors 112FL to 112RR. Specifically, as shown in FIG. 11, in step S1, the output signals of the wheel speed sensors 112FL to 112RR are read, and in the next step S2 ', any two wheel speeds V1, V2 is selected and it is determined whether it has changed by a predetermined value or more. This judgment is N
When it is O, the process proceeds to step S7, and the anti-skid brake control and the traction control are performed as usual. When the determination is YES, the process proceeds to step S3 'and the above 2
It is determined whether the difference between the two wheel speeds V1 and V2 is within a predetermined range. When this determination is NO, the above step S7
If YES, it is considered that the vehicle is in an accelerating or decelerating state, and the process proceeds to step S5 'to output the signals of the selected wheel speeds V1 and V2.
It is determined whether or not there are wheel speed sensors 112FL to 112RR other than 12FL to 112RR and the wheel speed signals of which have changed rapidly. If this determination is NO, step S
If YES, the wheel speed sensors 112FL to 112RR whose wheel speed has suddenly changed are considered to be in an abnormal state, and the antiskid brake control and traction control are stopped in step S6.

In this embodiment, by the steps S2 'and S3' in the above flow, the difference between any two wheel speeds V1 and V2 among the four wheel speeds is within a predetermined range and both wheel speeds V1 and V1. A vehicle acceleration / deceleration determination means 134 for determining the acceleration or deceleration state of the vehicle is configured by detecting that V2 changes by a predetermined value or more.

When the vehicle acceleration / deceleration determining means determines in step S5 'that the vehicle is in the acceleration / deceleration state, the wheel speed sensors 112FL to 112RR other than the wheel speed sensors 112FL to 112RR for outputting the signals of the wheel speeds V1 and V2. A sensor abnormality detecting unit 132 'is configured to determine that the wheel speed sensors 112FL to 112RR in which the wheel speed signal has changed rapidly are abnormal.

In this embodiment, when it is determined that the vehicle is in the acceleration / deceleration state, the wheel speed sensors 112FL other than the wheel speed sensors 112FL to 112RR used for the determination are used.
~ 112RR output signal sudden change is detected, if there is a sudden change in the signal, it is the wheel speed sensor 112FL ~ 11FL.
Each projection 51a of the rotor 51 and the pole 52 in the 2RR
It can be determined that the wheel speed sensors 112FL to 112RR are abnormal due to the increase in the gap 1 between the front end and the tip. In this case, the same operational effects as those of the first and second embodiments can be obtained.

In particular, in the above procedure, if it is determined that only when the vehicle is accelerating and that the wheel speed sensors 112FL to 112RR in which the wheel speed signal rapidly changes during the acceleration are determined to be abnormal, the vehicle is decelerating. Wheel sensor 1 by locking the wheels 7FL to 7RR when detecting
There is an advantage that a sensor abnormality can be reliably detected without erroneously determining that the output signal of 12FL to 112RR suddenly decreases.

[0071]

As described above, according to the first aspect of the present invention, the wheel speed sensor detects the rotational speed of the wheel, and the slip control is performed based on the detected wheel speed. In, the maximum wheel speed of a plurality of wheel speeds is a predetermined value or more, and the stable running state of the vehicle is determined by the state that the rate of change of the maximum wheel speed is below a predetermined range for a certain period of time, In this state, the vehicle speed sensor with no output signal is judged to be abnormal and the slip control is stopped, so even if two wheel speed sensors are abnormal at the same time based on one maximum wheel speed, it is possible to ensure that It is possible to detect and stop the slip control.

According to the second aspect of the present invention, it is detected that any two wheel speeds out of the plurality of wheel speeds are equal to or higher than a predetermined value and that the difference between the two wheel speeds is within a predetermined range, and the vehicle speed is detected. In this condition, the vehicle speed sensor with no output signal is determined to be abnormal and the slip control is stopped in that state. Therefore, based on the two wheel speeds, the two wheel speed sensors simultaneously become abnormal. Even if it falls, it can be detected reliably and in a short time, and the slip control can be stopped.

According to the third aspect of the invention, the acceleration state or deceleration of the vehicle is based on the fact that the difference between any two wheel speeds is within a predetermined range and both wheel speeds are changing at a predetermined value or more. When the output signal of a wheel speed sensor other than the sensor used for the above acceleration / deceleration determination suddenly changes in that state, the wheel speed sensor is determined to be in an abnormal state. In the speed sensor, an abnormal state in which the gap between the rotating portion and the rotation detecting portion becomes large can be detected, and the slip control can be stopped.

According to the fourth aspect of the present invention, when the acceleration state of the vehicle is detected, the wheel speed sensor other than the wheel speed sensor that outputs the wheel speed signal, and the wheel speed sensor in which the wheel speed signal sharply changes are determined to be abnormal. By doing so, it is possible to reliably detect the abnormality of the wheel speed sensor.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing a signal processing procedure in the controller in the first embodiment of the present invention.

FIG. 3 is a schematic front view of a wheel speed sensor.

FIG. 4 is a diagram showing a time change characteristic of an output signal of a wheel speed sensor.

FIG. 5 is a configuration diagram of a slip control device according to the first embodiment.

FIG. 6 is a characteristic diagram showing a relationship between a slip ratio, a friction coefficient, and a lateral drag coefficient.

FIG. 7 is a time chart diagram in anti-skid brake control.

FIG. 8 is a time chart diagram in traction control.

FIG. 9 is a circuit diagram for determining respective slip target values for an engine and a brake.

FIG. 10 is a view corresponding to FIG. 2 showing a second embodiment.

FIG. 11 is a view corresponding to FIG. 2 showing a third embodiment.

[Explanation of symbols]

 1 ... Engine 3 ... Automatic transmission 7FL, 7FR ... Front wheel (steering wheel) 7RL, 7RR ... Rear wheel 21FL-21RR ... Brake 101 ... AT controller 111 ... Controller 112FL-112RR ... Wheel speed sensor 131, 131 '... Vehicle traveling determination Means 132, 132 '... Sensor abnormality detecting means 133 ... Control stopping means 134 ... Acceleration / deceleration determining means V, V1, V2 ... Wheel speed Vmax ... Maximum wheel speed

Claims (4)

[Claims] 1. A slip control device comprising a wheel speed sensor for detecting a rotation speed of a wheel, wherein slip control is performed based on the wheel speed detected by the wheel speed sensor, wherein A vehicle running determination means for determining the running state of the vehicle by detecting that the maximum wheel speed is equal to or higher than a predetermined value and the rate of change of the maximum wheel speed is within a predetermined range for a certain period of time. When the vehicle traveling determination means determines that the vehicle is traveling, a sensor abnormality detecting means for determining a wheel speed sensor having no output signal as an abnormality, and an abnormality of the wheel speed sensor is detected by the sensor abnormality detecting means. A slip control device, comprising: a control stopping means for stopping the slip control. 2. A slip control device comprising a wheel speed sensor for detecting a rotation speed of a wheel, wherein slip control is performed on the basis of the wheel speed detected by the wheel speed sensor. A vehicle traveling determination means for determining the traveling state of the vehicle by detecting that any two wheel speeds are equal to or more than a predetermined value and the difference between the two wheel speeds is within a predetermined range; When it is determined that the vehicle is traveling by the sensor abnormality detection means that determines that the wheel speed sensor with no output signal is abnormal, and when the abnormality of the wheel speed sensor is detected by the sensor abnormality detection means, the slip A slip control device comprising a control stopping means for stopping control. 3. A slip control device comprising a wheel speed sensor for detecting a rotation speed of a wheel, wherein slip control is performed based on the wheel speed detected by the wheel speed sensor, wherein And a vehicle acceleration / deceleration determination means for determining the acceleration or deceleration state of the vehicle by detecting that the difference between any two wheel speeds is within a predetermined range and that both wheel speeds are changing by a predetermined value or more. When the vehicle acceleration / deceleration determining means determines that the vehicle is in an acceleration / deceleration state, a wheel speed sensor other than the wheel speed sensor that outputs the wheel speed signal and the wheel speed signal that has changed abruptly is determined to be abnormal. A slip control device comprising: a sensor abnormality detecting means; and a control stopping means for stopping the slip control when an abnormality of the wheel speed sensor is detected by the sensor abnormality detecting means. 4. The sensor abnormality detection means is a wheel other than a wheel speed sensor that outputs a wheel speed signal when the vehicle acceleration / deceleration determination means determines the acceleration state of the vehicle, and the wheel speed signal changes sharply. The slip control device according to claim 3, wherein the slip control device is configured to determine that the speed sensor is abnormal.