JPS63181002A - Actuator controller by computer - Google Patents

Abstract

PURPOSE:To keep steering torque constant, by controlling an actuator driving means with a constant control signal based on the output of a timer means which resets a computer periodically when abnormality is generated in the computer. CONSTITUTION:The titled device is provided with the timer means 2 which detects the abnormality of the computer 1 and sends a reset signal S to the computer 1 periodically, a constant value control command generating means 6 which generates a constant value control command for the actuator driving means 3, a switching means 4 which switches a command to the actuator driving means 3 from a computer command A to the command B of a constant value control command generating means 6 only when the abnormality is generated in the computer 1, and a switch driving means 5 which drives the switching means 4 by starting up the driving means 5 for a constant time longer than the cycle of the reset signal S setting the reset signal S as trigger. In such a way, it is possible to prevent a control current to an actuator from being fluctuated with the reset signal outputted from the timer means 2 at an abnormal time.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a computer-based actuator control device that changes the operating state of an actuator in response to commands from a computer.

<Prior art> In power steering systems for automobiles, a microcomputer detects the driving state and changes the steering characteristics. It is necessary to control and change the opening degree of the solenoid valve.

As shown in FIG. 4, the microcomputer that changes the opening degree of an actuator such as a solenoid valve is provided with a timer means 200 as a fail-safe device in the event of an abnormality such as runaway of the microcomputer 100. This timer means 200 is configured to periodically reset the microcomputer 100 by a reset signal S when it detects an abnormality such as runaway of the microcomputer 100.

<Problems to be Solved by the Invention> However, in such a conventional system, when an abnormality occurs in the microcomputer 100, the timer means 200
Since the microcomputer 100 is reset periodically, the current flowing through the actuator SQL also pulsates in synchronization with the reset signal S, and as a result, the steering torque also pulsates, resulting in a problem that stable steering cannot be ensured. Ta.

<Means for Solving the Problems> FIG. 1 is an overall configuration diagram for clearly demonstrating the present invention. a timer means 2 that detects an abnormality in the computer 1 and periodically sends a reset signal S to the computer 1; a constant value control command generation means 6 that generates a constant value control command to the actuator drive means 3; A switch means 4 switches the command to the actuator drive means 3 from the computer command A to the command of the constant value control command generation means 6 only when there is an abnormality in The switch drive means 5 is also provided with a switch drive means 5 which is activated for a long fixed period of time to drive the switch means 4.

<Operation> The actuator driving means is controlled by a constant control signal based on the output of the timer means that periodically resets the computer when the computer is abnormal.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 2, numeral 10 is a computer comprised of a microprocessor, memory, etc., to which a vehicle speed signal V from a vehicle speed sensor in the enclosure and a steering angle signal θ from a steering angle sensor in the enclosure are input. An interface 11 is connected thereto.

The command signal So output from the computer 10 via the DA converter 12 is supplied to the comparator 14 of the actuator driving means 20 and compared with the sawtooth wave generated from the sawtooth wave generation circuit 15. This comparator 14 outputs a pulse with a duty width proportional to the magnitude of the command signal So, changing the current flowing through the coil SQL.

Reference numeral 13 denotes timer means such as a watchdog timer, which inputs a pulse vctK of a constant frequency generated by a predetermined program from the computer 10, and this pulse Vcl
When the frequency of k stops, abnormally decreases, or increases, the computer 10 determines that there is an abnormality, and periodically generates a reset signal S to the computer 10.

21 is a switch driving means which inputs the reset signal S generated from the timer means 13 and switches the switch means 22 to change the command to the actuator driving means 20 from the command from the computer 10 to the command from the constant value control command generating means 23; It is. This switch driving means 21 includes resistors RIO to R16, a capacitor C10, and an inverter At.
, comparator A2. Transistor Tr. , Tr, , is a triggerable timer, and the resistance value of the resistor 13 is multiplied by the capacitance of the condenser C10 using the reset signal S periodically generated from the timer means B as a trigger due to an abnormality in the computer 10. Activated for a time constant.

The switch means 22 is a switch means constituted by resistors R20 to R22 and Tr2° to Trz□. This switch means 22 responds to the signal output from the switch drive means 21 to trigger the Trz. ~Turn on Tr2□.

The constant value control generating means is constituted by resistors R1 and R2, and is configured to output a constant command signal Vo when the computer 10 is abnormal. Further, the constant value command signal vo can be expressed by the following formula.

Next, the operation shown in FIG. 2 will be explained based on the time chart shown in FIG. 3.

In the normal operating state of the computer 10, FIG.
), the computer 10 outputs a pulse VeLK of a constant frequency. However, when the computer 10 goes out of control, the frequency of the pulse cLK stops, drops abnormally, or becomes high. Therefore, when the timer means 13 detects this abnormality, it periodically outputs a reset signal S (Lo
The transistor TrlO of the switch driving means 21 is periodically turned ON and OF+'', and the capacitor CIO is repeatedly charged and discharged by the transistor Trll. As a result, both VCC of the capacitor CIO are
When the set voltage (1) across the resistor 15, which is divided by the resistors R14 and R15, is compared by the comparator A2, the result is as shown in FIG. 3(d). That is, the switch driving means 21 operates to drive the switch means 22 while the timer means 13 detects an abnormality in the computer 10. Therefore, the output of the switch driving means 21 causes the transistor Trz of the switching means 22 to be activated. ~Tr2□ is O
When N, the command from the computer 10 is set to Low level, and the command value from the computer 10 is no longer input to the actuator driving mechanism 20, and the actuator driving means 20 is driven by the constant voltage Vo generated from the constant value control command generating means 23. become controlled.

As described above, when the period of the constant frequency pulse V CLK generated from the computer 10 is abnormal, the constant value control command generating means outputs a constant control command from the computer IO command to the actuator driving means 20. A reset signal S for periodically resetting the computer 1o so that it can be controlled by commands originating from the
This periodic reset is triggered by 47. Since the switch means 22 is driven by the switch drive means 21 which is activated for a certain period of time longer than the period of the number S, even if the computer 10 frequently repeats the abnormal state and the normal state, the switch means 22 is not switched frequently. As a result, the current flowing through the actuator SQL does not pulsate and the steering torque T is increased as shown in FIG. 3(f). can be kept constant.

<Effects of the invention> As described above, in the present invention, the combination 1-
Actuator drive that switches the switch means and drives the actuator by a switch drive means that is triggered by a reset signal generated from a timer means that periodically resets the computer when the computer is abnormal and is driven for a certain period longer than the period of the reset signal. Since the command for controlling the means is switched from the computer command to the command for the constant value control command generating means that generates a constant control command, the control current to the actuator will fluctuate depending on the reset signal output from the timer means in the event of an abnormality. It goes without saying that this can be prevented, and even if the computer quickly returns to a normal state from an abnormal state, the actuator is controlled by the command of the constant value control command generating means for a certain period of time without switching the switch means immediately. In order to
Even if the abnormal state and normal state of the computer frequently change, the current flowing through the actuator will not pulsate in synchronization with the reset signal, and there is an advantage that the steering torque can be kept constant.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention; FIG. 1 is a block diagram showing the overall configuration of the control circuit; FIG. 2 is an electric circuit diagram showing a specific example of FIG. 1; 3 (al to (n) is a time chart showing the operation of the circuit shown in FIG. 2, and FIG. 4 is a blower diagram showing a conventional computer-based actuator control device. 1.10... Computer, 2 ,13.WDT...
timer means, 3, 20... actuator drive means;
4.22...Switch means, 5゜21...Switch drive means, 6.23...Constant value control command generation means, S
QL...actuator.

Claims (1)

[Claims] An actuator control device that controls an actuator driving means to change the operation of the actuator according to a command from a computer, further comprising: a timer means for detecting an abnormality in the computer and periodically sending a reset signal to the computer; constant value control command generating means for generating a constant value control command to the actuator driving means; and a switch for switching the command to the actuator driving means from the computer command to the command of the constant value control command generating means only when the computer is abnormal. A computer-based actuator control device, comprising: means for controlling an actuator, and switch driving means for driving the switch means by starting the switch means for a certain period of time longer than the period of the reset signal using a reset signal from the timer means as a trigger.