JPH1029525A - Abnormality detection method for antilock brake controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute a performance monitor of an antilock brake control by a simple constitution. SOLUTION: An abnormality detection method for an antilock brake controller is so constituted that a valve drive circuit is controlled by being operated by a microcomputer 2 based on information from a wheel speed sensor 1. In this case, a same processing is performed in a processing cycle of operation for a plurality of times, a plurality of processing results are compared, and when a plurality of processing results are coincided with each other, the processing results are judged to be normal, however, when they are not coincided together, the processing results are judged to be abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antilock brake control for a vehicle.

[0002]

2. Description of the Related Art Conventionally, in an anti-lock brake control device, a fail-safe microprocessor is arranged in addition to a main ABS microprocessor to detect a failure of the main ABS microprocessor (Japanese Patent Laid-Open No. 2-29657).
No. 0). Alternatively, an abnormality is detected by monitoring each other by using a dual microcomputer (see Japanese Patent Application Laid-Open No. 4-215556).

However, there are the following problems. <A> If the processing is performed in a dual system, a double circuit configuration is required, and the circuit becomes complicated and expensive. <B> If a monitoring circuit for monitoring arithmetic processing is added in addition to the microcomputer, the circuit becomes complicated and the device becomes expensive.

[0004]

[Problems to be solved by the invention]

<A> The present invention resides in an abnormality detection method for an antilock brake control device capable of detecting an abnormality with a simple configuration.

[0005]

SUMMARY OF THE INVENTION The present invention comprises a wheel speed sensor, a microcomputer, and a valve drive circuit, and controls the valve drive circuit by calculating with the microcomputer based on information from the wheel speed sensor. In the abnormality detection method of the anti-lock brake control device, the same processing is executed a plurality of times within one processing cycle of the microcomputer to obtain a processing result, and the processing results of the plurality of times are compared. If so, the processing result is determined to be normal, and if the processing results do not match, the processing result is determined to be abnormal. A pulse is output from the microcomputer for each processing of the microcomputer, and the pulse is monitored by a watchdog timer to detect an abnormality of the microcomputer. And wherein the identifying, in the abnormality detecting method for an antilock brake control system.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. <A> Outline of anti-lock brake control device The anti-lock brake control device is based on the signal from the wheel speed sensor 1 for each wheel, and the microcomputer 2 uses the information necessary for anti-lock brake control such as wheel speed and vehicle speed. Is calculated, and the valve drive circuit 3 is controlled to drive the brake hydraulic pressure valve 5 to perform brake control of each wheel.

At this time, if an abnormality occurs in the processing of the microcomputer 2, the anti-lock brake control is not performed correctly, which may be dangerous. Therefore, the arithmetic processing of the microcomputer 2 is monitored. If an abnormality occurs, for example, a lamp for notifying the abnormality is turned on, the switch element 6 is shut off, and the power supplied to the hydraulic valve 5 is shut off. Further, the operation of the microcomputer 2 is monitored by the watchdog timer 4, and if an abnormality is determined, the antilock brake control is stopped in this case as well.

<B> Processing of the microcomputer The microcomputer 2 performs input processing of a signal from the wheel speed sensor 1 and, based on the input data,
Calculation processing of information necessary for antilock brake control such as wheel speed and vehicle body speed is performed, and output processing of a drive signal of the hydraulic valve 5 for braking is performed according to the processing result.
As shown in FIG. 2, the microcomputer 2 performs input processing, arithmetic processing, and output processing during one processing cycle.

<C> Monitoring abnormality of microcomputer processing The microcomputer 2 repeats the same arithmetic processing a plurality of times in the same processing cycle. For example, the same arithmetic processing is repeated twice, and the results are compared.

For example, in FIG. 2, in a first processing cycle, an A input process is performed in response to a signal from the wheel speed sensor 1, and in a second processing cycle, an A operation is performed based on the A input processed data. Processing is performed. Here two identical A
Operation processing is performed. At the same time, the B input process is also performed in this processing cycle. Further, in the third processing cycle, the A output processing is performed based on the calculation result of the A calculation processing together with the two B calculation processings, and the result is output to the valve driving circuit 3. Further, C input processing is also executed.

If the comparison results of the same arithmetic processing match, the microcomputer 2 determines that the arithmetic processing is performed normally. If not, the microcomputer 2 determines that the arithmetic processing is abnormal, and determines in a safe direction. Will be dealt with. For example, the same arithmetic processing is repeated twice and compared again, and if an abnormality still occurs, the antilock brake control is stopped and the normal brake control state is set. Alternatively, the antilock brake control is immediately stopped without repetition, and the normal brake control state is set.

If the same process is repeated three or more times, a majority decision can be taken on the result. If two or more match, the result is regarded as correct and the result is used for antilock brake control. can do. In the case where the majority decision is taken, for example, when the microcomputer 2 malfunctions for a moment due to a noise signal, the antilock brake control can be continued by taking the majority decision.

<D> Monitoring by Watchdog Timer The watchdog timer 4 is a microcomputer 2
The operation of is monitored. For example, when the microcomputer 2 is normal, a pulse signal is continuously output at regular intervals, for example, at each of a plurality of processes executed in one processing cycle, and the watchdog timer 4 detects the signal, If the period fluctuates, it is determined that there is an abnormality, the power supply to the microcomputer 2 and the hydraulic valve 5 is stopped, and the antilock brake control can be stopped. Note that one processing cycle is provided with a small margin, and it is determined that there is a slight variation as normal, and that a variation of ± 50%, for example, is abnormal.

[0014]

According to the present invention, the following effects can be obtained. <A> In the present invention, a single microcomputer monitors itself, eliminating the need for a conventional double microcomputer or a monitoring circuit for monitoring the operation of the microcomputer. It can be configured. <B> Since the same processing is performed at different times, it is easy to detect an instantaneous malfunction of the microcomputer due to excessive noise.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an anti-lock brake device.

FIG. 2 is an explanatory diagram of a processing cycle of a microcomputer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Wheel speed sensor 2 ... Microcomputer 3 ... Valve drive circuit 4 ... Watchdog timer 5 ... Hydraulic valve 6 ... Switch element

Claims (2)

[Claims] An anti-lock brake control device comprising a wheel speed sensor, a microcomputer, and a valve drive circuit, wherein the microcomputer controls the valve drive circuit based on information from the wheel speed sensor and controls the valve drive circuit. In the detection method, the same processing is executed a plurality of times within one processing cycle of the microcomputer to obtain a processing result, and the processing results of the plurality of times are compared. If the processing results of the plurality of times match, the processing result is normal. A method for detecting an abnormality in the anti-lock brake control device, characterized in that if the values do not match, the processing result is determined to be abnormal. 2. A method according to claim 1, wherein the microcomputer outputs a pulse for each of a plurality of processes executed, and outputs the pulse to a watchdog timer. A method for detecting an abnormality in the antilock brake control device, wherein the abnormality is monitored by monitoring the microcomputer.