JPH02164668A - Abnormality detecting method for electrically driven power steering - Google Patents

Abstract

PURPOSE:To shorten the time from starting of a system to assist-start to improve safety when the absence of a driver is detected by automatically performing abnormality detection of an auxiliary steering motor or a steering torque sensor. CONSTITUTION:When a system ia started, a fail safe clutch 13 is disconnected through a clutch driving circuit 19 by a microprocessor 18. A voltage is then applied through a drive-amplifier 20 to an auxiliary steering motor 12 by the microprocessor 15. Abnormality of the motor 12 is detected through an edge number measuring circuit 17 based on output signal from a rotation detector 14 by the microprocessor 18. In this case, the absence of a driver is detected by the microprocessor 18 based on each signal from a door lock signal generating circuit 21 and an engine key insertion signal generating circuit 22. When the driver is absent, abnormality detection can thus be automatically performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for detecting an abnormality in an electric power steering device for an automobile.

Conventional technology Recently, electric power steering has been put into practical use as a new power steering system, but due to the system configuration, if the motor locks or an abnormality occurs in the sensor signal, it is extremely dangerous and may cause an accident. have. For this reason, motors and sensors are checked when the system is started.

The conventional detection method described above will be described below with reference to the drawings.

FIG. 3 is a flowchart showing the conventional detection method,
Figure 4 shows the output waveform of a rotation detector that detects a motor abnormality in a conventional example, Figure 5 shows the output waveform of a sensor that detects a sensor abnormality, and Figure 6 shows the schematic configuration of an electric power steering device. It is.

In FIG. 6, 11 is a torque sensor, 12 is a motor,
13 is a fail-safe clutch, 14 is a rotation detector,
15 is an output voltage range monitoring circuit that checks the range of output values of the sensor; 16 is a time measurement circuit; 17 is an edge number measurement circuit that measures the number of edges as motor rotation information;
8 is a microprocessor (M, P, U); 19 is a clutch drive circuit that disconnects the clutch; and 20 is a drive amplifier that drives the motor.

A detection method in the above configuration will be explained.

First, when the driver starts the system by starting the engine, etc., the fail-safe clutch 13 is disengaged, voltage is applied to the motor 12, and an abnormality in the motor is detected based on the output signal of the rotation detector 14. When the motor does not rotate due to a locked state or the like, the waveform becomes as shown in FIG. 4(b), and the number of edges within a certain period of time is measured by the edge number measuring circuit shown in FIG. 6, 17.

Regarding the sensor, as shown in FIG. 5, it is confirmed by the output voltage range monitoring circuit 15 and time measuring circuit 16 in FIG. 6 that the sensor output value is within the usable range for a certain period of time.

As described above, the microprocessor (M
, P, U) 18.

Problems to be Solved by the Invention However, with the above method, it takes too long to start the system, and it is not possible to monitor the progress of sensors and motors over time, leaving the system unable to confirm conditions such as being on the verge of destruction. However, there is a problem that the system may start up.

In view of the above-mentioned drawbacks, the present invention provides a method for early system start-up, reliable detection of changes in motors and sensors, and early detection of abnormalities.

Means for Solving the Problems In order to solve the above problems, the abnormality detection method of the present invention is as follows:
This is a detection method that automatically activates only the detection function and stores its contents even when it is determined that there is no driver present.

Operation The present invention uses the above-described method to shorten the time from system startup to assist start, and also makes it possible to know the changes in each signal and motor, thereby achieving high safety.

Embodiment Hereinafter, an abnormality detection method according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a flowchart of abnormality detection according to the present invention, and FIG. 2 is a schematic configuration diagram of the system.

In Fig. 2, the difference from the conventional example is that 21 door lock signal generation circuits and 22 engine key insertion signal generation circuits are added; other than that, the functions are the same, so the same numbers are assigned. , a detailed explanation will be omitted.

The operation of the abnormality detection method for the electric power steering system configured as described above will be explained below with reference to FIGS. 1 and 2.

If the condition that there is no driver presently is determined based on the fact that the engine key is not inserted and the doors are locked, the engine key insertion signal generation circuit 2 shown in Fig. 2
2 detects whether or not the key is inserted, and the door lock signal generating circuit 21 similarly detects the presence or absence of the key insertion. When these two conditions are met, the microprocessor (M) determines that there is no driver.

If P, U) is determined, edge measurement for detecting the rotational state of the motor as described in the conventional example, time measurement of the output value of the sensor, etc. are automatically performed. This measurement result is always stored in RAM and its changes are understood (.In addition, by constantly determining whether there is an abnormality in the system when the driver is unattended from the measurement information obtained as described above, However, there is no time loss when starting up the system, and control can be started immediately, making it extremely easy to operate.

Effects of the Invention As described above, the present invention automatically detects abnormalities in motors and sensors when the driver is not present, thereby reducing the abnormality detection time that would otherwise occur when the driver gets on board and starts the system. The system can be started up quickly because there is no need for this, and since changes in detected information are always recorded, it is possible to obtain information such as when the motor rotation speed is about to drop, thereby alerting the driver at an early stage. It is possible to improve safety by being able to call out the following information.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a method for detecting an abnormality in an electric power steering device according to the present invention, FIG. 2 is a block diagram of an electric power steering device according to an embodiment of the present invention, and FIG. FIG. 2 is a configuration diagram of a second electric power steering device showing a method for detecting an abnormality in the electric power steering device. 11...Sensor, 12...Motor, 1
3... Fail-safe clutch, 14...
... Rotation detector, 15 ... Output voltage range monitoring circuit, 16 ... Time measurement circuit, 17 ...
・Edge number measuring circuit, 18...Microprocessor, 19...Clutch drive circuit, 20...
... Drive amplifier, 21 ... Door lock signal generation circuit, 22 ... Engine key insertion signal generation circuit. Name of agent: Patent attorney Shigetaka Awano and one other name

Claims (2)

[Claims] (1) An abnormality detection method for electric power steering in which an abnormality detection device for a steering assist motor or a sensor is activated in a state where it is determined that the driver is not present. (2) The method for detecting an abnormality in an electric power steering according to claim 1, wherein information about the motor and the sensor is always stored, and based on the changes thereof, the current normality or defect is determined and the occurrence of a failure is estimated.