JPH07112785B2 - Fail-safe device for constant-speed traveling device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fail-safe device for a constant speed traveling device, which controls ON / OFF of power supply to a constant speed traveling control actuator.

[Conventional technology]

A conventional constant-speed traveling device uses a microcomputer when driving and controlling an actuator for constant-speed traveling control that opens and closes a throttle valve provided in an intake pipe of an engine. The microcomputer 17 shown in FIG. 2 outputs a pulse train signal having a predetermined frequency as a watchdog signal. This watchdog signal is differentiated by the watchdog signal processing means 4, then rectified so as to cut the minus side, and further inverted. The inverted signal is integrated by the reset signal generating means 5. This integrated value is returned to approximately O by the refresh signal if the inverted signal includes a refresh signal that is instantaneously brought to the "L" level in synchronization with the rise of the watchdog signal.

The reset signal generator 5 compares the integrated value with a predetermined level. If the integrated value is equal to or lower than the predetermined level, the watchdog signal is normally output from the microcomputer 17, and the state is continued as it is. If the refresh signal is not generated and the integrated value thereof exceeds the predetermined level, the watchdog signal is not normally output from the microcomputer 17, and the microcomputer 17 is abnormal, so the reset signal generating means 5 is Generate a reset signal. The microcomputer 17 is reset by this reset signal,
The operation is stopped and initialized.

[Problems to be Solved by the Invention]

Since the conventional fail-safe device for a constant speed traveling device is configured as described above, the microcomputer 17 may not be reset even if the output of the watchdog signal is stopped and the reset signal is output. However, in the worst case, the signal for controlling the throttle valve in the opening direction is still output, which is not preferable for safety.

The present invention has been made to solve the problems as described above, and when the reset signal is generated due to the output stop of the watchdog signal or the like, the power is supplied to the actuator.
The purpose is to obtain a fail-safe device for a constant-speed traveling device that can be controlled to F and ensure safety.

[Means for Solving the Problems]

A failsafe device for a constant speed traveling device according to the present invention is a command signal input means, a cancel signal input means, a watchdog signal generating means, and a reset means for detecting a stop of output of the watchdog signal and outputting a reset signal. And supply power to the actuator according to the input signal.
A power supply control means is provided for ON / OFF control and OFF control by inputting a reset signal.

[Work]

The fail-safe device for a constant speed traveling device according to the present invention,
When the power supply control means inputs the reset signal from the reset means, the supply of power to the actuator is controlled to be OFF, and the operation of the actuator is stopped.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a speed signal generating means for generating a signal having a frequency corresponding to the traveling speed of the vehicle, 2 is a command signal input means for generating a command signal for instructing constant speed traveling by an external operation, and 3 is a It is a cancel signal input means for instructing to cancel the constant speed traveling by an external operation. Reference numeral 4 is a watchdog signal processing means for inputting a watchdog signal and processing it into a signal for integration. Reference numeral 5 is for comparing the integrated value of the output signal of the watchdog detection means 4 with a predetermined level. It is a reset signal generating means for outputting. Reference numeral 6 denotes a NOR gate, each input terminal of which has a cancel signal input means 3 and a reset signal generation means 5
It is connected to the. Reference numeral 7 denotes a D flip-flop (hereinafter referred to as D / F / F) as a signal holding circuit, which has a D input terminal (D terminal) pulled up by a power source through a pull-up resistor 8 and a reset terminal (R terminal). ) Is NOR gate 6
, The clock input terminal (CL terminal) is connected to the command signal output means 2, and the set terminal (S terminal) is grounded. The normal output terminal (Q terminal) is connected to the base of the transistor 9 whose emitter is grounded. The emitter is connected to the collector of the transistor 9 via the base resistor 10 of the transistor 12 connected to the DC power supply 11. Reference numerals 13 and 14 are first and second solenoid valves that constitute a drive unit of a well-known negative pressure type actuator that drives a throttle valve (not shown) provided in an intake pipe of the engine for constant speed traveling control. When the solenoid valve 13 is turned on, negative pressure is introduced from an engine negative pressure source (not shown), and when the second solenoid valve 14 is turned on, atmospheric pressure is introduced, and the rest is cut. Reference numerals 13a and 14a denote coils of the first and second solenoid valves 13 and 14, respectively, one end of which is commonly connected to the collector of the transistor 12 and the other end of which is connected to each collector of the transistors 15 and 16 whose emitters are grounded. It is connected. Reference numeral 17 is a microcomputer for controlling constant speed running, which is composed of an input circuit, an output circuit, a CPU, a RAM, a ROM, an oscillator for generating a watchdog signal, etc. 5 is connected to the output terminals of the elements, and the output circuit is connected to the watchdog signal processing means 4 and the bases of both transistors 15 and 16. Further, the power supply control means 18 for controlling ON / OFF of the supply of the power supply 11 to the actuator according to the type of the input signal is composed of elements indicated by reference numerals 6 to 10 and 12.

Next, the operation will be described. In the normal state, the constant speed running is not set, it is in the canceled state, and DF
F7 has been reset. Therefore, since the Q terminal is at "L" level, both the transistors 9 and 12 are OFF, and the coils 13a and 14a of the first and second solenoid valves and the power supply 11 are in the non-conduction state. When a command signal having a rising edge is generated from the command signal input means 2 by the driver's operation, the D / F / F7 inputting this signal to the CL terminal has a resistor 8 at the D terminal.
It is set because it is pulled up to "H" level via. Therefore, the Q terminal becomes "H" level, the transistor 9 turns on, and it is pulled in, and the transistor 12 turns on.
Turn on. When the transistor 12 is turned on, the coils 13a and 14a of the first and second solenoid valves and the power supply 11 are brought into conduction. On the other hand, the microcomputer 17 enters a constant speed traveling control state when the command signal is input from the command signal input means 2 and controls both transistors 15 and 16 to be turned on and off based on the signal input from the speed signal generation means 1. . When the transistor 15 is turned on, the coil 13a of the first solenoid valve is energized, and when the transistor 16 is turned on, the coil 14a of the second solenoid valve is energized, and the rest is non-energized. First and second solenoid valves
The opening of a throttle valve (not shown) is adjusted according to the ON / OFF status of 13 and 14, and constant speed running control is performed. Further, the microcomputer 17 outputs a watchdog signal of a pulse having a predetermined cycle to the watchdog signal processing means 4 during operation. The watchdog signal processing means 4 differentiates this watchdog signal, rectifies and inverts it after differentiation, and outputs it to the reset signal generating means 5. Reset signal generating means 5
Outputs the signal when the output of the watchdog signal is stopped and exceeds the predetermined level by integrating the inverted signal and comparing it with a predetermined level, and if it is determined that it is below the predetermined level, the output is left as it is. From "H" level to "L"
The level is changed and the reset signal is output. The NOR gate 6 receives the reset signal from the reset signal generating means 5 or the cancel signal from the cancel signal input means 3 generated by the driver's operation, and changes the signal from "L" level to "H" level. Is output to the R terminal of DF / F7 (S terminal is grounded) to reset DF / F7. By this reset, the Q terminals of D, F, F7 are set to "L" level, and the initial state is set, and the coils 13a, 14a of the first and second solenoid valves and the power source 11 are brought out of conduction.

Further, when the reset signal is generated from the reset signal generating means 5 and the microcomputer 17 is reset by this signal, the operation is stopped. Further, when the cancel signal is generated from the cancel signal input means 3, the microcomputer 17 which has input this signal stops the constant speed traveling control and waits for the next command signal input. The relationship between the ON / OFF states of the first and second solenoid valves 13 and 14 and the state of the throttle valve (not shown) is as shown in the table below.

In the above negative pressure type actuator, the first and second solenoid valves 13 and 14 are communicated with the diaphragm chamber, the diaphragm of the diaphragm chamber and the throttle valve are connected by a shaft, and the diaphragm is connected to the diaphragm chamber by a spring. It is configured to be pressed.

Further, although the case of the negative pressure type actuator has been described in the above embodiment, the present invention can be applied to an electric motor type actuator composed of a DC motor and an electromagnetic clutch, and the same effect as that of the above embodiment can be obtained.

〔The invention's effect〕

As described above, according to the present invention, when the reset signal is generated by stopping the output of the watchdog signal, the power supply to the actuator is controlled to be turned off, so that the operation of the actuator is surely stopped. It is possible to obtain a highly safe product.

[Brief description of drawings]

FIG. 1 is a block diagram of a failsafe device for a constant speed traveling device according to an embodiment of the present invention, and FIG. 2 is a configuration diagram of a conventional failsafe device for a constant speed traveling device. In the figure, 2 ... Command signal input means, 3 ... Cancel signal input means, 4 ... Watchdog signal processing means, 5
...... Reset signal generating means, 11 ...... power supply, 13,14 ...... solenoid valve, 13a, 14a …… solenoid valve coil, 17 …… microcomputer, 18 …… electromagnetic control means. The same reference numerals in the drawings indicate the same or corresponding parts.

Front page continuation (72) Inventor Hiroyuki Kozuki 840 Chiyoda-cho, Himeji City, Hyogo Prefecture Mitsubishi Electric Corporation Himeji Works (56) Reference JP-A-63-258228 (JP, A)

Claims (1)

[Claims] 1. A command signal input means for generating a command signal for instructing a constant speed traveling set by an external operation, and a cancel signal for generating a cancel signal for instructing a cancellation of the constant speed traveling set by an external operation. Signal input means, watchdog signal generating means for generating a watchdog signal of a pulse train, reset means for detecting that the generation of the watchdog signal has stopped and outputting a reset signal, the command signal, the cancel signal , And inputting the reset signal, ON / OFF control the power supply to the constant speed traveling control actuator that drives the slot valve of the engine according to the type of the input signal, and by the reset signal to the actuator Constant-speed running characterized by having a power supply control means for controlling the power supply of the置用 fail-safe devices.