JP2589321B2 - Automatic vehicle speed control - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic vehicle speed control device used for automatically controlling a traveling speed of a vehicle to a set speed. (Prior Art) As this kind of automatic vehicle speed control device, there have been various types of conventional configurations, and some of them have a circuit configuration shown in FIG. That is, a vehicle speed sensor 101 that outputs operation data proportional to the actual vehicle speed, a command switch 102 that incorporates a set switch 102a, a resume switch 102b, and an accelerator switch 102c to output a cruise command signal, a vent valve 103, and a vacuum valve 104 And a negative pressure control type actuator 106 that drives a throttle valve by adjusting a negative pressure by operation of the safety valve 105, and in response to an OFF operation after an ON operation of a set switch 102a of the command switch 102. Vehicle speed storage means for storing operation data of the vehicle speed sensor 101,
Control means for sending a command to the actuator 106 via a vent valve drive circuit 107 and a vacuum valve drive circuit 108 in response to the difference between the actual vehicle speed and the stored vehicle speed; and a microcomputer 110 in the controller 109. A constant voltage circuit 111 also in the controller 109 for supplying a predetermined voltage to the microcomputer 110;
And a power supply circuit 113 for supplying a power supply 112 to the actuator 106 in accordance with the above-mentioned command. In this vehicle speed automatic control device, in response to the OFF operation after the ON operation of the set switch 102a of the command switch 102, the actual vehicle speed at that time is stored in the vehicle speed storage means of the microcomputer 110, and the actual speed and the stored vehicle speed are stored. The control means of the microcomputer 110 responds to the difference between the drive circuit 107 for the bend valve and the drive circuit 1 for the vacuum valve.
08 to the vent valve 103 of the actuator 106
Alternatively, the vacuum valve 104 is operated to rotate the throttle valve in the closing direction or the opening direction so that the actual vehicle speed is made to match the stored vehicle speed so that the vehicle travels at a constant speed, which is very convenient for traveling on a highway or the like. Things. (Problems to be Solved by the Invention) However, in the above-described conventional automatic vehicle speed control device, since the operating voltage range of the microcomputer 110 is defined, the voltage of the power
Although 12 V was adjusted to 5 V and supplied to the microcomputer 110, if the constant voltage circuit 111 failed due to an abnormality such as overvoltage, the voltage supplied to the microcomputer 110 may be changed depending on the failure condition. If the operating voltage of the computer 110 does not fall within the operating voltage range and the situation continues for a long time, the microcomputer 110
There is a problem that the absolute operation stability cannot be guaranteed. (Objects of the Invention) The present invention has been made in view of the above-mentioned conventional problems, and in a situation where a predetermined voltage cannot be supplied to a microcomputer, the actuator is deactivated to reduce the reliability of the system. It is an object of the present invention to provide an automatic vehicle speed control device that can be improved.

Configuration of the Invention

(Means for Solving the Problems) The configuration of the automatic vehicle speed control device according to the present invention for achieving the above object will be described with reference to a functional block diagram shown in FIG. A vehicle speed sensor 1 for outputting operation data proportional to speed, a command switch 2 for outputting a cruise command signal, an actuator 5 for driving a throttle valve 4 provided in the vehicle, the power supply, a vehicle speed sensor, a command switch and an actuator Connected to a vehicle speed storage means for storing operation data output by the vehicle speed sensor in response to operation of the command switch.
3a and a microcomputer 3 having control means 3b for comparing operation data output from the vehicle speed sensor with data stored in the vehicle speed storage means and generating a command signal for driving the actuator in accordance with the difference between the two. A constant voltage circuit 6 connected to the power supply and supplying a predetermined voltage to the microcomputer; and a microcomputer connected to the power supply and control means of the microcomputer and connected to the actuator. In a vehicle speed automatic control device comprising a power supply circuit 8 for supplying a current to the actuator from the power supply according to a command signal, the controller is connected to the power supply and the constant voltage circuit, and outputs an output voltage of the constant voltage circuit. Is supplied from the microcomputer when the voltage exceeds a first reference voltage. When the output voltage of the first comparator and the constant voltage circuit for cutting off the command signal supplied to the circuit is lower than the second reference voltage, the command signal supplied from the microcomputer to the power supply circuit is cut off. A stop means 9 comprising a second comparator is provided. (Operation) In the automatic vehicle speed control device according to the present invention, as shown in FIG. 1, when the voltage supplied from the constant voltage circuit 6 to the microcomputer 3 becomes lower than the predetermined voltage or becomes higher than the predetermined voltage. In order to stop the situation,
Makes the power supply circuit 8 inactive, and prevents the actuator 5 from operating in accordance with a command from the microcomputer 3. Hereinafter, the present invention will be described with reference to the drawings. FIG. 2 and FIG. 3 are views showing one embodiment of the vehicle speed automatic control device according to the present invention. FIG. 2 is an explanatory diagram showing a circuit configuration of the vehicle speed automatic control device. In FIG. 2, reference numeral 11 denotes a vehicle speed sensor (corresponding to the vehicle speed sensor 1 shown in FIG. 1) which outputs operation data proportional to the actual vehicle speed. ), 12 are command switches that output a cruise command signal (corresponding to the command switch 2 shown in FIG. 1)
This command switch 12 has a set switch
12a, resume switch 12b and accelerator switch 12c
Is included. Outputs from the vehicle speed sensor 11 and the command switch 12 pass through an interface 14 and an interface 15 in the controller 13, respectively.
16 (corresponding to the microcomputer 3 shown in FIG. 1). The microcomputer 16 has a vehicle speed (actual vehicle speed) at the time of the OFF operation or a vehicle speed (actual vehicle speed) at the time of the ON operation of the set switch 12a in response to an OFF operation after the ON operation of the set switch 12a of the command switch 12. The vehicle speed storage means (corresponding to the vehicle speed storage means 3a shown in FIG. 1) for storing operation data (for example, the number of pulse signals) for outputting speed (speed) from the vehicle speed sensor 11 and the actual vehicle speed output from the vehicle speed sensor 11 A control means (corresponding to the control means 3b shown in FIG. 1) for driving an actuator 20, which will be described later, corresponding to the difference between the number of pulse signals and the number of pulse signals stored in the vehicle speed storage means is incorporated. 20 is an actuator (actuator 5 shown in FIG. 1)
This actuator 20 includes a vent valve 21 and a safety valve 22 as shown in FIG.
And a vacuum valve 23. One end of each of the bend valve 21 and the safety valve 22 is open to the atmosphere, and one end of the vacuum valve 23 is connected to an intake manifold (negative pressure source). In addition, each valve 21, 22,
The other end of 23 communicates with a negative pressure chamber 27 formed by the casing 25 and one side of the diaphragm 26 (the right side in FIG. 3), and communicates with the other side of the diaphragm 26 (the left side in FIG. 3). Is connected to one end of the control wire 28,
The other end of the control wire 28 is connected to a throttle valve shaft 29 that drives a throttle valve (not shown) (corresponding to the throttle valve 4 shown in FIG. 1). Further, 31 is in the controller 13 and turns on the vent valve 21 according to the output from the microcomputer 16.
A drive circuit for a vent valve for controlling the off state, a vacuum drive circuit for controlling the on / off state of the vacuum valve in accordance with an output from the microcomputer, and a reference numeral 33 are also provided for the control circuit. A power supply circuit for the actuator (corresponding to the power supply circuit 8 shown in FIG. 1) for turning on / off the power supply to the actuator 20 according to the output from the microcomputer 16. Reference numeral 37 denotes a brake switch, 38 denotes a brake lamp, and a signal for canceling the system when a brake is operated is transmitted through an interface 39 in the controller 13.
Is input to the microcomputer 16 via Further, 41 is a constant voltage circuit (corresponding to the constant voltage circuit 6 shown in FIG. 1) which supplies a predetermined voltage (approximately 5 V) to the microcomputer 16 in the controller 13, 42 is a reset circuit, and 43 is a power supply ( The power supply 7 shown in FIG. 1), 45 is a cruise lamp, 46 is in the controller 13, detects the output voltage of the constant voltage circuit 41, and the output voltage of the constant voltage circuit 41 is lower than a predetermined voltage. This is a stop circuit (corresponding to the stop means 9 shown in FIG. 1) that turns off the power supply circuit 33 when the power supply circuit 33 is high or high. Explaining the stop circuit 46, the resistors R1 to R4 for setting the reference voltage and the zener diode ZD1 and the constant voltage circuit 4
A first comparator OP that sucks, via a diode D1, a control signal output from the microcomputer 16 to the power supply circuit 33 when the output voltage of the microcomputer 1 exceeds the reference voltage.
1 and a second comparator OP2 that attracts, via a diode D2, a control signal output to the power supply circuit 33 from the microcomputer 16 when the output voltage of the constant voltage circuit 41 is lower than the reference voltage. It has a circuit configuration. Next, the operation of the vehicle speed automatic control device having such a configuration will be described. First, in order to operate the vehicle speed automatic control device, the main switch 44 is turned on. At this time, the stop circuit 46 detects the output voltage of the constant voltage circuit 41, and the vehicle speed sensor 11 outputs a pulse signal that is operation data proportional to the actual vehicle speed, and sends the pulse signal to the microcomputer 16 in the controller 13. The input signal is sampled at regular time intervals, and the microcomputer 16 always recognizes the number of pulse signals proportional to the vehicle speed for each sampling. In this state, after the set switch 12a is turned on and the set signal is input to the microcomputer 16, when the set switch 12a is turned off and the set signal is released, the output voltage of the constant voltage circuit 41 is changed to the microcomputer. When the operating voltage is within the range of the operating voltage of 16, the first and second comparators OP1 and OP2 of the stop circuit 46 do not operate together, the cruise lamp 45 is turned on, and the microcomputer 16 is connected to the power supply circuit. A power supply 43 is supplied to the actuator 20 by operating the actuator 33, and the bend lube 21 and the safety valve 22 are turned on in accordance with an instruction of the microcomputer 16 to close the chamber, shut off the negative pressure chamber 27 from the atmosphere, and turn off the set switch 12a. Open vacuum by turning on the vacuum valve 23 with set initialization corresponding to the vehicle speed at the time of the OFF operation. Introducing a negative pressure into the chamber 27, the throttle valve shaft 29 via the control wire 28 is held at a predetermined position. That is, the actuator 20 operates according to the instruction of the microcomputer 16. Thereafter, even when the accelerator pedal is released, the throttle valve shaft 29 is held at the predetermined position, so that the vehicle travels at a constant speed. If the constant voltage circuit 41 causes the output voltage to become higher than a predetermined voltage due to some abnormality in the controller 13 (for example, overvoltage or the like), the condition is determined by the first comparator.
The first comparator OP1 senses the control signal output from the microcomputer 16 and outputs the control signal from the microcomputer 16 to the power supply circuit 33 via the diode D1, and cuts off the power supply to the actuator 20. Conversely, when the output voltage of the constant voltage circuit 41 becomes lower than the predetermined voltage, the second comparator OP2 detects the situation, and outputs a control signal output from the microcomputer 16 to the power supply circuit 33 to the diode D2. , The second comparator OP2 sucks the power to cut off the power supply to the actuator 20. Therefore, when the output voltage is increased or decreased due to the abnormality of the constant voltage circuit 41 and does not fall within the operating voltage range of the microcomputer 16, the microcomputer 20 is deactivated in order to deactivate the actuator 20. There is no adverse effect of 16 on the actuator 20, and the actuator 20 does not operate according to the instruction of the microcomputer 16. In the above-described embodiment, the negative pressure control type actuator 20 has been described as an example. However, a positive pressure control type actuator, a motor drive type actuator and the like are also included in the technical scope of the present invention. Needless to say.

【The invention's effect】

As described above, according to the vehicle speed automatic control device of the present invention, a power supply, a vehicle speed sensor that performs operation data proportional to the actual vehicle speed of the vehicle, a command switch that outputs a cruise command signal, An actuator for driving a provided throttle valve; and a controller connected to the power supply, a vehicle speed sensor, a command switch, and an actuator, wherein the controller outputs an operation output from the vehicle speed sensor in response to operation of the command switch. Vehicle speed storage means for storing data; and control means for comparing operation data output by the vehicle speed sensor with data stored in the vehicle speed storage means and generating a command signal for driving the actuator in response to a difference between the two. And a microcomputer connected to the power supply, A constant voltage circuit for supplying a predetermined voltage to a computer; a constant voltage circuit connected to the power supply and control means of the microcomputer; connected to the actuator; and a current supplied from the power supply to the actuator according to a command signal generated by the microcomputer. And a power supply circuit for supplying the power to the microcomputer. The controller is connected to the power supply and the constant voltage circuit, and the microcomputer controls the output voltage of the constant voltage circuit when the output voltage exceeds a first reference voltage. And a command supplied from the microcomputer to the power supply circuit when the output voltage of the first comparator and the constant voltage circuit for cutting off the command signal supplied to the power supply circuit is lower than a second reference voltage. With the configuration including the stopping means including the second comparator for interrupting the signal, When the voltage circuit fails a certain abnormality, since the stop means by the detection of the output voltage to the power supply circuit inoperative,
Even if an output voltage that does not fall within the operating voltage range is applied to the microcomputer and the operation of the microcomputer is in an unstable state, the actuator can be inactivated. Therefore, an excellent effect that the reliability of the system can be improved can be obtained.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of an embodiment of an automatic vehicle speed control device according to the present invention, FIG. 2 is an explanatory diagram showing a circuit configuration of an embodiment of the automatic vehicle speed control device of the present invention, and FIG. FIG. 2 is a sectional view showing the structure of the actuator shown in FIG. 2, and FIG. 4 is an explanatory view showing a circuit configuration of a conventional automatic vehicle speed control device. 1 ... Vehicle speed sensor, 2 ... Command switch, 3 ...
Microcomputer, 3a vehicle speed storage means, 3b control means, 4 throttle valve, 5 actuator, 6 constant voltage circuit, 7 power supply, 8 power supply circuit, 9 stop means.

Claims (1)

(57) [Claims] 1. A power supply, a vehicle speed sensor for outputting operation data proportional to the actual vehicle speed of a vehicle, a command switch for outputting a cruise command signal, an actuator for driving a throttle valve provided in the vehicle, A vehicle speed sensor, a command switch, and a controller connected to the actuator, wherein the controller stores the operation data output by the vehicle speed sensor in response to the operation of the command switch; A microcomputer having control means for comparing operation data with data stored in the vehicle speed storage means and generating a command signal for driving the actuator in accordance with a difference between the two; and A constant voltage circuit for supplying a predetermined voltage to the computer, A vehicle power supply control circuit connected to the power supply and control means of the microcomputer and connected to the actuator, and a power supply circuit for supplying a current from the power supply to the actuator in accordance with a command signal generated by the microcomputer; In the apparatus, the controller is connected to the power supply and the constant voltage circuit, and shuts off a command signal supplied from the microcomputer to the power supply circuit when an output voltage of the constant voltage circuit exceeds a first reference voltage. Stopping means comprising a first comparator and a second comparator for interrupting a command signal supplied from the microcomputer to the power supply circuit when the output voltage of the constant voltage circuit is lower than a second reference voltage. An automatic vehicle speed control device comprising: