JP2693172B2 - Anti-skid controller using automobile failure determination device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel braking device using a hydraulic pressure detection element, and more particularly to a failure determination device for a hydraulic pressure detection element used in a wheel braking device and a failure determination device therefor. It is preferably implemented in the anti-skidding control device used.

2. Description of the Related Art By depressing a foot brake pedal (hereinafter referred to as "brake pedal"), the hydraulic pressure of a wheel cylinder provided on each wheel rises, and a braking operation is started on each wheel. When the brake pedal is instantly and strongly pressed while running, a strong braking force is applied to each wheel by the hydraulic braking means, and the rotational speed of the wheel (hereinafter referred to as "wheel speed") is rapidly reduced. Eventually, it becomes a locked state, that is, a state where the wheel speed is zero. With the rotation of the wheels locked,
The steering ability of the steering wheel is lost, resulting in a dangerous state. In particular, when the friction coefficient between the wheel and the road surface is small, the rotation of the wheel is likely to be locked and further caution is required for the brake operation.

However, it is extremely difficult for the vehicle driver to adjust the amount of depression of the brake pedal in order to obtain the maximum braking force, because of the relationship with the friction coefficient with the road surface as described above.

The anti-skidding control device is installed in an automobile in order to reduce the above-mentioned difficulty. The slip ratio of the wheel is calculated from the traveling speed of the automobile (hereinafter referred to as "vehicle speed") and the wheel speed, and the slip ratio is calculated. Is a device that controls the hydraulic pressure in the wheel cylinders so that is a value that produces the maximum braking force. As described above, since the anti-skidding control device controls the hydraulic pressure in the wheel cylinder, by detecting the hydraulic pressure value by the hydraulic pressure detection element provided in the wheel cylinder and feeding the anti-skidding control calculation with feedback, a higher precision can be obtained. Anti-skidding control is realized. For example, the level of the friction coefficient between the wheel and the road surface can be known from the relationship between the wheel slip ratio and the hydraulic pressure value, and the braking output can be increased by switching the control output depending on the level. be able to. In addition, anti-skid control with excellent responsiveness can be realized by increasing or decreasing the wheel cylinder oil pressure based on the oil pressure value.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, in the anti-skid control device using the hydraulic pressure detection element, the hydraulic pressure value is one of the important parameters of the anti-skid control calculation. Therefore, if the value is abnormal, the accurate anti-skidding control cannot be curtailed, and the driver who performs the brake operation by believing that the anti-skidding control is performed may be in a dangerous situation.

An object of the present invention is to solve the above-mentioned problems, and detects a failure of a hydraulic pressure detection element,
An object of the present invention is to provide an anti-skid control device in which anti-skid control is continued even if a failure is found.

Means for Solving the Problems According to the present invention, a brake pedal is depressed to generate a friction braking force by hydraulic braking means provided on each wheel of an automobile, and the hydraulic pressure is increased during friction braking. In an anti-skidding control device that increases the friction coefficient between a wheel that has been decompressed or held and the road surface, a hydraulic pressure detection element that is provided for each wheel of an automobile and that detects the hydraulic pressure, and detects the amount of depression of the brake pedal In response to the output from the depression amount detecting means, the oil pressure detecting element and the depression amount detecting means, when the output of the oil pressure detecting element is different from a preset value corresponding to the depression amount of the brake pedal, A means for judging that the detecting element has a failure, and a means for judging that the hydraulic pressure detecting element is normal in response to the output of the failure judging means. When it is determined that the oil pressure detecting element is abnormal, the anti-skid control is performed using the output of the oil pressure detecting element. The anti-skid control device includes an anti-skid control means for performing anti-skid control using a normal hydraulic pressure detecting element.

Furthermore, according to the present invention, the brake pedal is depressed to generate the friction braking force by the hydraulic braking means provided on each wheel of the automobile, and the hydraulic pressure is increased by the control signal during the friction braking. In an anti-skidding control device that increases the friction coefficient between the wheel and the road surface by increasing, decreasing, or holding the pressure, a hydraulic pressure detection element that is provided for each wheel of the automobile to detect the hydraulic pressure, and the amount of brake pedal depression When the depression amount detecting means for detecting, and the output from the hydraulic pressure detecting element and the depression amount detecting means, and the output of the hydraulic pressure detecting element is different from a preset value corresponding to the depression amount of the brake pedal, A means for judging that the oil pressure detecting element has a failure, and a means for judging that the oil pressure detecting element is normal in response to the output of the failure judging means. Is executed, the first anti-skid control program for performing anti-skid control using the output of the oil pressure detecting element is executed, and when it is determined that the oil pressure detecting element is abnormal, the output of the oil pressure detecting element is not used and the anti-skid control is executed. An anti-skid control device comprising: an anti-skid control means for executing a second anti-skid control program for controlling.

In the present invention, the first anti-skidding control program should store the detected hydraulic pressure detected by the hydraulic pressure detection element when a lock occurs during braking of the wheel, and the control signal should increase the pressure. Is expressed, the step of generating a pressurization control signal for making the hydraulic pressure smaller than the hydraulic pressure stored in the storage means by a predetermined ratio is included.

Further, the present invention controls the hydraulic pressure so that the friction coefficient between the wheel and the road surface is increased by increasing or decreasing the pressure of the hydraulic pressure of the hydraulic braking means provided in association with the wheel of the automobile by a control signal. Then, in an anti-skid control device that performs an anti-skid control operation for each wheel, a hydraulic pressure detection element that is provided for each wheel of the automobile to detect the hydraulic pressure, and responds to the control signal and the output of the hydraulic pressure detection element, When the hydraulic pressure should be increased, decreased or held by the control signal and the hydraulic pressure detected by the hydraulic pressure detection element is different from the value corresponding to the control signal, the hydraulic pressure detection element is out of order. And a means for judging that the failure judgment means responds to the output of the failure judgment means. When the oil pressure detection element is normal, the output of the oil pressure detection element is used to perform anti-skid control. When it is determined that the pressure detection element is abnormal, an anti-skid control means for performing anti-skid control by using the hydraulic pressure detection element in the abnormal state and the normal hydraulic pressure detection element provided on the wheel on the same side with respect to the left and right of the vehicle body. It is an anti-skid control device characterized by including.

Further, the present invention controls the hydraulic pressure of the hydraulic braking means provided in relation to the wheels of the automobile so as to increase or decrease the pressure of the hydraulic pressure by a control signal or hold the hydraulic pressure so that the friction coefficient between the wheel and the road surface becomes large. In an anti-skidding control device that performs anti-skidding control operation for each wheel, a hydraulic pressure detection element that is provided for each wheel of a vehicle and that detects the hydraulic pressure; and a control signal that responds to the output of the control signal and the hydraulic pressure detection element. When the oil pressure is to be increased, decreased, or maintained by the above, when the oil pressure detected by the oil pressure detection element is different from the value corresponding to the control signal, it means that the oil pressure detection element is out of order. And a first responsive to the output of the failure determination means for performing anti-skid control using the output of the oil pressure detection element when the oil pressure detection element is normal. An anti-skid control means for executing a second anti-skid control program for executing an anti-skid control without using the output of the hydraulic pressure detecting element, when the skid control program is executed and it is determined that the hydraulic pressure detecting element is abnormal. Is an anti-skidding control device.

Further, according to the present invention, a friction braking force is generated by a hydraulic braking means provided on a wheel by depressing a brake pedal, and a predetermined anti-skid should be controlled in the state where the friction braking force is generated. In a failure determination device for an anti-skid control device, which when the condition is satisfied, increases or decreases the pressure of the hydraulic pressure braking device by a control signal or controls the hydraulic pressure so that the friction coefficient between the wheel and the road surface increases, When the anti-skid control condition is not satisfied in response to the output of the hydraulic pressure detecting element for detecting the hydraulic pressure, the depression amount detecting means for detecting the depression amount of the brake pedal, the output of the hydraulic pressure detecting element and the depression amount detecting means, In response to the outputs from the hydraulic pressure detection element and the depression amount detection means, the output of the hydraulic pressure detection element is the brake pedal. When the value differs from the preset value corresponding to the amount of depression, it is determined that the hydraulic pressure detection element has failed, and when the anti-skid control condition is satisfied, the control signal and the output of the hydraulic pressure detection element are responded to. When the hydraulic pressure should be increased, decreased or held by the control signal and the hydraulic pressure detected by the hydraulic pressure detection element is different from the value corresponding to the control signal, the hydraulic pressure detection element is out of order. It is a failure determination device for an anti-skidding control device, characterized in that it includes a means for determining that it is.

Operation In the present invention, when it is determined that the oil pressure detection element is normal, anti-skid control is performed using the output of the oil pressure detection element, and when it is determined that the oil pressure detection element is abnormal, an abnormal condition is detected. The anti-skid control is performed by using a normal oil pressure detecting element provided on wheels on the same side with respect to the left and right sides of the vehicle body.

Further, according to the present invention, when it is determined that the hydraulic pressure detecting element is normal, the first anti-skid control program for executing the anti-skid control using the output of the hydraulic pressure detecting element is executed to determine that the hydraulic pressure detecting element is abnormal. When the determination is made, the second anti-skid control program that executes the anti-skid control without using the output of the hydraulic pressure detection element is executed. And in the first anti-skidding control program,
The detected hydraulic pressure detected by the hydraulic pressure detection element when the wheel is locked is stored, and the control signal indicating that the pressure should be increased is a hydraulic pressure that is smaller than the stored hydraulic pressure by a predetermined ratio. Take control.

Further, in the present invention, when the anti-skidding control condition is not satisfied, when the output from the hydraulic pressure detecting element is different from the preset value corresponding to the depression amount of the brake pedal, the hydraulic pressure detecting element is out of order. to decide. Further, when the anti-skidding control condition is satisfied, when the output from the hydraulic pressure detecting element is different from the value corresponding to the control signal for controlling the hydraulic pressure of the hydraulic braking means, it is determined that the hydraulic pressure detecting element is out of order. To do.

Embodiment FIG. 1 is a block diagram of an anti-skidding control device according to an embodiment of the present invention. The hydraulic pressure of the hydraulic oil in the master cylinder 1 is increased by stepping on the brake pedal 2 or by driving the oil pump motor 3 that supplies the hydraulic oil flowing back to the reservoir tank 8 to the master cylinder 1. Pipes p1 to p4 are provided between the master cylinder 1 and the solenoid control valves 4a to 4d, and the hydraulic oil in the master cylinder 1 is given to the solenoid control valves 4a to 4d via the pipes p1 to p4. . In addition, the electromagnetic control valves 4a-4d and the wheel cylinders 5a-5d
Pipes p5 to p8 are provided between and, and the hydraulic oil in the master cylinder 1 increases the hydraulic pressure in the wheel cylinders 5a to 5d provided in the hydraulic braking means via the electromagnetic control valves 4a to 4d. , Brake the wheels 6a to 6d. Solenoid control valves 4a-4d
Is a three-position electromagnetic control valve, and any one of the three positions (pressure increasing, holding, pressure reducing) is selected by a control signal from a processing circuit 7 constituted by an individual semiconductor or a microcomputer.

In the electromagnetic control valve 4a in FIG. 1, when the pressure increasing position 4a1 is selected, it means that the pipe p1 and the pipe p5 are in the conductive state, and when the holding position 4a2 is selected, the pipe p1 and the pipe p5 are shown. Represents that the pipes are in the cutoff state, and that the pipe p5 and the pipe p9 are in the conduction state when the decompression position 4a3 is further selected. When the electromagnetic control valve 4a is controlled to the pressure increasing position 4a1 by the processing circuit 7, the hydraulic oil in the master cylinder 1 flows into the wheel cylinder 5a via the pipes p1 and p5 and is controlled to the pressure reducing position 4a3. The hydraulic oil in the wheel cylinder 5a is
Reflux to the reservoir tank 8 via 9. The above-described operation is the same for the electromagnetic control valves 4b to 4d, and the subscripts 1, 2, and 3 of the reference numeral 4a mean the pressure increasing position, the holding position, and the pressure reducing position, respectively. The same applies to 4d.

P valves 9b and 9d provided in the middle of the pipes p6 and p8 are wheel cylinders 5b provided on the left rear wheel 6b and right rear wheels 6d.
It is a valve for limiting the hydraulic pressure of the hydraulic oil applied to the wheel cylinder 5d provided in the above so as not to exceed a predetermined value.

A stroke sensor 10 mounted on the brake pedal 2 and realized by a linear potentiometer or the like for detecting a linear position is a means for detecting the depression amount of the brake pedal 2, and the detected amount is given to the processing circuit 7. To be

The hydraulic pressure sensors 11a to 11d attached to the wheel cylinders 5a to 5d are hydraulic pressure detecting elements realized by a strain gauge type or a semiconductor, and the detected pressure is given to the processing circuit 7.

Wheel speed sensors 12a to 12d are provided on the wheels 6a to 6d to detect the rotation speeds of the wheels, and the detection signals are given to the processing circuit 7 as wheel speed signals. As the wheel speed sensors 12a to 12d, for example, a large number of notches and protrusions at equal intervals are provided in the circumferential direction of a detection plate made of a ferromagnetic material fixed to a wheel shaft, and an electromagnetic wave is attached near the circumference of the detection plate. There is a sensor that detects a wheel speed signal having a frequency proportional to the wheel speed by means of a pickup.

The operation of the anti-skidding control device configured as described above will be briefly described. When the anti-skidding is not controlled, the master cylinder 1 applies the brake pressure generated by the depression of the brake pedal 2 to the electromagnetic control valves 4a to 4d and the electromagnetic control valves 4a to 4d so that the brake pressure is applied to the wheel cylinders 5. Is set to the pressure increasing position. When the brake pedal 2 is strongly depressed while the vehicle is running, the pressure in the wheel cylinders 5a-5d rises sharply and the wheels 6a-6d
Starts the slip. The processing circuit 7 is a wheel speed sensor 12a.
Based on the signal from ~ 12d, the slip rate of each wheel (expressed by the ratio between the vehicle speed and the wheel speed and the vehicle speed) and the wheel acceleration (the previously detected wheel speed and the currently detected wheel speed) And the quotient of the previously detected time and the currently detected time) are calculated, and when the slip ratio and the wheel deceleration (negative acceleration) exceed a predetermined value, anti-skid control is started. That is, the processing circuit 7 sets the electromagnetic control valves 4a to 4d to the pressure reducing position, reduces the hydraulic pressure in the wheel cylinders 5a to 5d, and restores the wheel speed. Then, the pressure increasing position, the holding position, or the pressure reducing position is selected and controlled so that the slip ratio of the wheel becomes the state in which the braking force is the highest. The above control is performed for each wheel and is controlled so that the highest braking force is generated for the entire vehicle.

Next, one embodiment of the anti-skidding control when using the hydraulic sensor will be described with reference to the flow chart shown in FIG. The process shown in FIG. 2 is a flow chart that is executed at predetermined constant time intervals. At step m1, the wheel slip rate level is determined. Strictly speaking, the slip ratio of the wheel is calculated from the vehicle speed and the wheel speed, but in the present embodiment, the slip ratio is 0% to 5%, 5%.
It is judged whether or not it belongs to any of the range of 10%, 10% to 20%, 20%. At step m2, the level of wheel acceleration is determined. Wheel acceleration level is also step
Similar to m1, it is determined to which of the predetermined wheel acceleration ranges it belongs.

At step m3, it is judged if the anti-skidding control start condition is satisfied. For example, when it is determined that the wheel slip ratio exceeds 10%, the wheel deceleration exceeds a predetermined value, and the brake pedal is depressed, the anti-skid control is started. When the anti-skidding control start condition is satisfied in step m3, the process proceeds to step m4, and the oil pressure in the wheel cylinders 5a to 5d at the start of the anti-skidding control is detected and stored. The stored hydraulic pressure is used as a basis for pressure increase control described later. From step m4 to step m5, the pressure reducing operation is performed. This pressure reducing operation is performed by setting the electromagnetic control valves 4a to 4d to the pressure reducing positions.

While the pressure reducing operation is being performed, it is determined in step m6 whether or not the pressure reducing end condition is satisfied. That is, the depressurizing operation is ended at the time when the sign of the wheel speed starting to recover is shown. If the decompression ending condition is satisfied in step m6, the process proceeds from step m7 to step m8, and the processing circuit 7 sends a control signal to the electromagnetic control valve 4 for switching the operating position of the electromagnetic control valves 4a to 4d from the decompression position to the holding position. To do.

At step m7, it is judged whether or not the holding end condition is satisfied. That is, the holding operation ends when it is determined that the wheel speed starts to increase and the wheel acceleration exceeds a predetermined value. Upon completion of the holding operation, the process proceeds from step m7 to step m9, and the pressure increasing operation is started at step m10.

The pressure increasing operation is performed by setting the electromagnetic control valve 4 to the pressure increasing position. Then, the ratio of the hydraulic pressure detected by the hydraulic pressure sensors 11a to 11d to the hydraulic pressure stored in step m4 is a predetermined ratio (for example, 80% or 90%).
When the pressure reaches, the pressure increasing state ends. When the boosted state ends, the electromagnetic control valve 4 is switched to the holding position.

When the boosting condition is completed in step m9, step
From m11 to step m12, the pulse pressure increasing operation is performed at regular intervals. Pulse pressure boosting operation is controlled by solenoid control valves 4a-4d
Is an operation in which the holding position and the pressure increasing position are alternately switched, and the pressure increasing operation corresponding to the pulse width of the control signal output from the processing circuit 7 is performed. By the pulse pressure increasing operation, the hydraulic pressure of the wheel cylinder 5 gradually increases, and the braking force of the wheels 6 gradually increases.

When the anti-skidding control ends, the solenoid control valves 4a-4d
Is set to the pressure increasing position so that the hydraulic pressure generated by the depression of the brake pedal 2 is applied to the wheel cylinders.

Next, the failure detection means of the hydraulic sensor will be described.
Fault detection of the hydraulic pressure sensor is different between when the anti-skidding is not controlled and when the anti-skidding is controlled, which will be described below.

When anti-skidding is not controlled, hydraulic pressure sensor 11a
When the detected hydraulic pressures of 11d exceed the hydraulic pressure range determined in advance by the depression amount of the brake pedal 2, it is determined that the hydraulic pressure sensor has failed. FIG. 3 is a graph for explaining the determination of normality / abnormality of the hydraulic sensor from the relationship between the depression amount of the brake pedal 2 and the wheel cylinder internal pressure.
In FIG. 3, line 11 is a line showing the relationship between the depression amount of the brake pedal 2 of the normal hydraulic pressure sensor and the wheel cylinder internal pressure. The amount of depression is detected by a stroke sensor 10 attached to the brake pedal 2. Line l2
Is the upper limit line for judging normality / abnormality, and line 13 is the lower limit line. Therefore, line l2 including line l1
The area between and the line l3 is determined as the normal area.

FIG. 4 is a flow chart of the hydraulic sensor failure determination program when the anti-skidding is not controlled. At step n1, it is determined whether the processing circuit 7 is performing anti-skidding control. If not controlled, step n2
3, the upper and lower limits of the normal hydraulic pressure value with respect to the depression amount from the stroke sensor 10 are set from the graph of FIG. At step n3, it is determined whether the oil pressure detected by the oil pressure sensor 11 is within the normal range set at step n2. If it is not within the normal range, the process proceeds from step n4 to step n5, and the failure processing of the hydraulic sensor is performed.

As the failure processing of the hydraulic sensor, for example, a processing of continuing the anti-skid control calculation by using the output of the same right or left hydraulic sensor on the left and right of the vehicle body with respect to the failed hydraulic sensor, or an anti-skid control calculation not using the hydraulic sensor is performed. .

FIG. 5 is a flow chart of an embodiment of a hydraulic sensor failure determination program during anti-skidding control. During the anti-skid control, the hydraulic pressure control signals from the processing circuit 7 determine whether the detected hydraulic pressures of the hydraulic pressure sensors 11a to 11d change with the same logic as the control signals.
Judge normality / abnormality.

At step r1, it is determined whether the processing circuit 7 is performing anti-skidding control. When the anti-skid control is being performed, the routine proceeds to step r2, where it is judged whether or not the pressure increasing control signal is sent from the processing circuit 7 to the electromagnetic control valves 4a to 4d. When the boosting control signal is sent, the process proceeds to step r3, where the current output of the hydraulic sensor is read and stored. At step r4, the difference between the previously stored output value of the hydraulic sensor and the presently stored output value of the hydraulic sensor is calculated. In step r5, it is judged whether or not the result calculated in step r4 is positive. Processing circuit 7
Since the pressure increase control signal is output from, the output value of the oil pressure sensor must be increased. If not, the process proceeds to step r6 and it is determined that the oil pressure sensor is out of order.
Further, when the control signal is held or depressurized, the same determination is made. In the case of holding, r2 becomes (holding) and r5 becomes (Δ
P = 0). Similarly, when a pressure reduction signal is output, r2 becomes (during pressure reduction) and r5 becomes (ΔPn <0). If the oil pressure sensor is out of order, the same processing as described in step n5 in FIG. 4 is performed.

Next, the anti-skid control when a failure of the hydraulic sensor is found will be described. The oil pressure sensors 11a to 11d are attached to the wheel cylinders 5a to 5d, which are attached to the respective wheels, and the processing circuit 7 is configured to operate the oil pressure sensors 11a to 11d.
The failure detection process is individually performed on each of a to 11d. When an abnormal hydraulic pressure sensor is found by the failure detection processing of the hydraulic pressure sensors 11a to 11d, the anti-skid control can be performed using another normal hydraulic pressure sensor.

In the anti-skid control, the hydraulic sensor can be used to determine the level of the coefficient of friction (μ) between the wheel and the road surface. For example, when the wheel lock starts when the wheel cylinder oil pressure is high, it can be determined as a high μ road surface, and when the wheel lock starts when the wheel cylinder oil pressure is low, the wheel μ road is low. Can be determined. The anti-skid control can be performed more smoothly by changing the pressure increasing time of the pressure increasing and the pulse pressure increasing in the anti-skid control for the friction coefficient level thus determined. Therefore, when it is determined that the hydraulic pressure sensor is abnormal, the friction coefficient level is determined using the outputs of the hydraulic pressure sensor in the abnormal state and the normal hydraulic pressure sensor provided on the wheels on the same side with respect to the left and right of the vehicle body. As a result, the anti-skid control of the wheel to which the abnormal oil pressure sensor is attached can be continued. For example, when the oil pressure sensor 11c of the left front wheel 6c is out of order, the friction coefficient level can be determined using the output of the oil pressure sensor 11b of the left rear wheel 6b, and the anti-skid control of the left front wheel can be continued.

In this way, the level of the friction coefficient is determined using the output of the normal hydraulic sensor provided on the wheel on the same side as the faulty hydraulic sensor. This is because it is considered that the friction coefficient level obtained from the output of the attached hydraulic sensor has the same friction coefficient level as that of the wheel to which the defective hydraulic sensor is attached.

The above failure detection processing is performed when there is a single malfunctioning hydraulic sensor, but when multiple malfunctions occur, the anti-skid control is performed by switching to control that does not use the output signal of the hydraulic sensor, as described below. You can continue. That is, the processing circuit 7 has a first anti-skid control program for performing anti-skid control using the hydraulic sensors 11a to 11d, and a second anti-skid control program for performing anti-skid control without using the hydraulic sensor.
The first or second anti-skid control program is executed by executing the above-described hydraulic sensor failure detection program. By performing such processing, the anti-skid control device can continue the anti-skid control regardless of whether or not there is a failure in the hydraulic sensor, and extremely high reliability can be realized.

FIG. 6 is a flow chart for explaining the anti-skid control when the hydraulic pressure sensors 11a to 11d are not used. In step s1, the processing circuit 7 determines whether or not to start the anti-skidding control. With the brake pedal 2 depressed, if the wheel slip ratio exceeds 10% and the wheel acceleration is lower than the predetermined wheel acceleration G ₁ , the anti-skid control is started. When the anti-skidding control is started, the process proceeds from step s2 to step s3, and the wheel slip rate level, that is, the wheel slip rate is included in any of 0 to 10%, 10% to 20%, and 20%. To judge. Then, in step s4, the acceleration level of the wheel is determined. The acceleration level of the wheel is obtained by calculating the difference between the previously detected wheel speed and the wheel speed detected this time, and the difference belongs to which region is divided by the predetermined accelerations G ₁ , G ₂ , and G ₃ . Be judged.

When the determination of the wheel slip ratio level and the determination of the wheel acceleration level are completed, the process proceeds to step s5, the friction coefficient level between the wheels 6a to 6d and the road surface is determined, and it belongs to either the high μ road or the low μ road. Is determined. The high μ road or the low μ road can be discriminated by the magnitude of the wheel acceleration when the wheel speed is recovered from the state where the wheel is locked or close to it, and when the wheel acceleration is larger than a predetermined acceleration, it is high. μ road, and if it is small, it is judged as low μ road. High μ
If it is judged that the road is on the road, the routine proceeds to step s6, where the output determined by the wheel slip ratio and the wheel acceleration is selected from the output control map for the high μ road shown in FIG. Then, in step s7, the output selected in step s6 is sent as a control signal to the electromagnetic control valves 4a-4d.

If it is determined in step s5 that the friction coefficient between the wheel and the road surface is a low μ road, the process proceeds to step s8, and is determined by the wheel slip rate and the wheel acceleration from the control map for the low μ road, which will be described later. Output is selected. When the output is selected in step s8, the process proceeds to step s7,
The selected output is sent to the electromagnetic control valves 4a-4d as a control signal.

After the anti-skid control described above is performed, if it is determined in step s2 that the condition for ending the anti-skid control is satisfied, the process proceeds to step s9, the anti-skid control is released, and the brake pedal 2 is depressed. The hydraulic pressure in the master cylinder is an electromagnetic control valve.
The electromagnetic control valves 4a to 4d are set to the pressure increasing positions so that they are supplied to the wheel cylinders 5a to 5d via the 4a to 4d. The anti-skidding control ending condition at step s2 is that the brake pedal 2 is released or the vehicle speed is 5k.
This is the case when it is less than m / H.

FIG. 7 is a control map for a high μ road used in the anti-skidding control flow chart of FIG. The control map shown in FIG. 7 is stored in the processing circuit 7, and is divided into 12 areas which are divided by the wheel slip rate and the wheel acceleration. Here, "pulse boosting" shown in the regions R1, R2, R3, R6, R7 means control for setting the boosting position only for the duration of the pulse width of the control signal sent from the processing circuit 7 to the electromagnetic control valves 4a-4d. The "pressure increase" shown in regions R4 and R8 means that the solenoid control valve is used to continuously increase the pressure of the wheel cylinders 5a to 5d.
It means to set 4a-4d continuously to the pressure increasing position. region
"Pulse pressure reduction" shown in R10 means control for setting the electromagnetic control valve in the pressure reduction position for the time of the pulse width sent from the processing circuit 7 to the electromagnetic control valves 4a to 4d, and "pressure reduction" shown in regions R5 and R9. The term "control" refers to control for continuously setting the electromagnetic control valves 4a to 4d to the decompression position. Furthermore, "hold" shown in areas R11 and R12
Is a control that sets the electromagnetic control valves 4a to 4d to the holding position and maintains the oil pressure in the wheel cylinder.

In the low μ road control map, only the “pulse pressure reduction” output in the region R10 is changed to the “pressure reduction” output in comparison with the high μ road control map shown in FIG. And other outputs are exactly the same as the control map for high μ road. The reference constant of the control map such as the wheel acceleration G ₁ may be changed.

As described above, according to this embodiment, the normality of the hydraulic sensor /
Abnormality can be detected both when anti-skid control is not controlled and during control, and even when a failure of the hydraulic sensor is detected, anti-skid control continues, so highly safe anti-skid control is possible. The device can be realized.

EFFECTS OF THE INVENTION As described above, the anti-skidding control device according to the present invention is provided with the means for detecting the failure of the oil pressure detecting element, so that the malfunction due to the failure of the oil pressure detecting element can be prevented in advance, and the malfunction of the control. Can be reliably prevented. Further, since the anti-skid control device according to the present invention is provided with a program for performing anti-skid control without using the hydraulic pressure detection element even when a failure of the hydraulic pressure detection element is found, a highly reliable anti-skid control device is provided. can do.

[Brief description of the drawings]

FIG. 1 is a block diagram of an anti-skid control device according to an embodiment of the present invention, FIG. 2 is a flow chart for explaining anti-skid control when a hydraulic sensor is used, and FIG. 3 is a stepping amount of a brake pedal and a wheel. A graph for explaining the normal / abnormal judgment of the pressure sensor in relation to the pressure in the cylinder. FIG. 4 is a flow chart of the hydraulic sensor failure judgment program when the anti-skidding is not controlled.
The figure shows the flow chart of the oil pressure sensor failure judgment program during anti-skid control, Fig. 6 is the flow chart for explaining the anti-skid control when the hydraulic sensor is not used, and Fig. 7 is the anti-skid control flow chart of Fig. 6. This is a control map for high μ roads. 1 ... Master cylinder, 2 ... Brake pedal, 3 ...
… Motor, 4a to 4d …… Electromagnetic control valve, 5a to 5d …… Wheel cylinder, 6a to 6d …… Wheel, 7 …… Processing circuit, 10 …… Stroke sensor, 11a to 11d …… Hydraulic pressure sensor, 12a to 12d …
… Wheel speed sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-191261 (JP, A) JP 62-20938 (JP, A)

Claims (6)

(57) [Claims] 1. A brake pedal is depressed to generate a frictional braking force by hydraulic braking means provided on each wheel of an automobile, and the hydraulic pressure is increased, reduced or maintained during frictional braking. In an anti-skidding control device for increasing the friction coefficient between a wheel and a road surface, a hydraulic pressure detecting element, which is provided for each wheel of an automobile and detects the hydraulic pressure, respectively, and a depression amount detecting means for detecting the depression amount of a brake pedal. When the output of the hydraulic pressure detecting element is different from a preset value corresponding to the stepping amount of the brake pedal in response to the outputs from the hydraulic pressure detecting element and the stepping amount detecting means, the hydraulic pressure detecting element fails. Means for determining that the oil pressure is detected, and when the oil pressure detection element is normal in response to the output of the failure judgment means, the oil pressure detection is performed. When the anti-skid control is performed using the output of the output element and it is determined that the hydraulic pressure detection element is abnormal, the hydraulic pressure detection element in the abnormal state and the normal hydraulic pressure provided on the wheels on the same side with respect to the left and right of the vehicle. An anti-skid control device comprising an anti-skid control means for performing anti-skid control using a detection element. 2. A brake pedal is depressed to generate a frictional braking force by hydraulic braking means provided on each wheel of an automobile, and the hydraulic pressure is increased by a control signal during frictional braking. In an anti-skidding control device that reduces or maintains the pressure to increase the friction coefficient between the wheel and the road surface, a hydraulic pressure detection element is provided for each wheel of the automobile to detect the hydraulic pressure, and the amount of brake pedal depression is detected. When the output from the hydraulic pressure detecting element and the output from the hydraulic pressure detecting element and the stepping amount detecting means is different from a preset value corresponding to the stepping amount of the brake pedal, A means for judging that the oil pressure detecting element is out of order, and a case where the oil pressure detecting element is normal in response to the output of the failure judging means. In this case, the first anti-skidding control program for performing anti-skidding control using the output of the oil pressure detecting element is executed, and when it is judged that the oil pressure detecting element is abnormal, the output of the oil pressure detecting element is not used and the anti-skidding control is executed. An anti-skid control device comprising: an anti-skid control means for executing a second anti-skid control program for controlling. 3. The first anti-skidding control program should store the detected hydraulic pressure detected by a hydraulic pressure detection element when a lock occurs during wheel braking, and the control signal should increase the pressure. And a step of generating a pressurization control signal for making the hydraulic pressure smaller than the hydraulic pressure stored in the storage means by a predetermined ratio. Anti-skidding control device. 4. The hydraulic pressure of hydraulic braking means provided in relation to the wheels of a vehicle is controlled by a control signal so as to increase, decrease or maintain the hydraulic pressure so that the friction coefficient between the wheel and the road surface increases. Then, in an anti-skid control device that performs an anti-skid control operation for each wheel, a hydraulic pressure detection element that is provided for each wheel of the automobile to detect the hydraulic pressure, and responds to the control signal and the output of the hydraulic pressure detection element, When the hydraulic pressure should be increased, decreased or held by the control signal and the hydraulic pressure detected by the hydraulic pressure detection element is different from the value corresponding to the control signal, the hydraulic pressure detection element is out of order. In response to the output of the failure determining means, when the oil pressure detecting element is normal, anti-skid control is performed using the output of the oil pressure detecting element, When it is determined that the detection element is abnormal, an oil pressure detection element in the abnormal state and an anti-skid control means for performing anti-skid control using a normal hydraulic pressure detection element provided on the wheels on the same side with respect to the left and right of the vehicle are provided. An anti-skidding control device comprising: 5. The hydraulic pressure of hydraulic braking means provided in relation to the wheels of an automobile is controlled by a control signal to increase, decrease or hold the hydraulic pressure to increase the friction coefficient between the wheel and the road surface. In an anti-skidding control device that performs anti-skidding control operation for each wheel, a hydraulic pressure detection element that is provided for each wheel of a vehicle and that detects the hydraulic pressure; and a control signal that responds to the output of the control signal and the hydraulic pressure detection element. When the oil pressure is to be increased, decreased, or maintained by the above, when the oil pressure detected by the oil pressure detection element is different from the value corresponding to the control signal, it means that the oil pressure detection element is out of order. A first anti-skidding control that uses the output of the hydraulic pressure detection element when the hydraulic pressure detection element is normal in response to the output of the failure determination means. And an anti-skid control means for executing a second anti-skid control program for executing anti-skid control without using the output of the hydraulic pressure detection element when it is determined that the hydraulic pressure detection element is abnormal. An anti-skidding control device. 6. A friction braking force is generated by a hydraulic braking means provided on a wheel by depressing a brake pedal, and a predetermined anti-skid should be controlled while the friction braking force is generated. In a failure determination device for an anti-skid control device, which when the condition is satisfied, increases or decreases the pressure of the hydraulic pressure braking device by a control signal or controls the hydraulic pressure so that the friction coefficient between the wheel and the road surface increases, When the anti-skid control condition is not satisfied in response to the output of the hydraulic pressure detecting element for detecting the hydraulic pressure, the depression amount detecting means for detecting the depression amount of the brake pedal, the output of the hydraulic pressure detecting element and the depression amount detecting means, In response to the outputs from the hydraulic pressure detection element and the depression amount detection means, the output of the hydraulic pressure detection element is the brake pedal output. When the value differs from the preset value corresponding to the amount of penetration, it is judged that the hydraulic pressure detection element is out of order, and when the anti-skid control condition is satisfied, the control signal and the output of the hydraulic pressure detection element are responded to. When the hydraulic pressure should be increased, decreased or held by the control signal, and the hydraulic pressure detected by the hydraulic pressure detection element is different from the value corresponding to the control signal, the hydraulic pressure detection element has failed. A failure determination device for an anti-skidding control device, characterized in that it includes means for determining that it is present.