JPH0367728A - Automatic vehicle speed control device - Google Patents

Abstract

PURPOSE:To inexpensively secure high reliability by prohibiting a driving motor of an actuator from rotating in the direction of opening a throttle valve to prevent unintentional increase in vehicle speed when various control means, driving means, etc., are abnormal, or control of vehicle speed is released. CONSTITUTION:Vehicle speed data by a vehicle speed sensor 1 are stored in a storage means 3 when a command switch 2 for outputting a cruise command is operated. On the other hand, an actuator 4 drives a throttle valve 5 through an electromagnetic clutch 4b by its motor 4a. A driving means 6 for rotating the motor 4a in forward and reverse, and a driving means 9 for turning on and off the electromagnetic clutch 4b are controlled by a control means 7 respectively in response to the difference between the actual vehicle speed and the stored vehicle speed. In the above devices, when the above various means 3, 7, 6, 9 and the electromagnetic clutch 4b are abnormal or control of the vehicle speed is released, rotating of the motor 4a in the direction of increasing the vehicle speed is prohibited by a prohibiting means 8.

Description

[Detailed description of the invention] [Purpose of the invention]

(Industrial Application Field) The present invention relates to an automatic vehicle speed control device that is used to visually control the traveling speed of a vehicle to a preset vehicle speed. (Prior Art) The above-mentioned automatic vehicle speed control devices have conventionally had various configurations, and some of them include, for example, a vehicle speed sensor that outputs vehicle speed data proportional to the actual vehicle speed;
A command switch that outputs a cruise command signal and a throttle lever that rotates the drive motor via an electromagnetic clutch)
It includes an actuator that drives the I<b>, a motor drive circuit that rotates the drive motor of the actuator in forward and reverse directions, and a clutch drive circuit that turns on and off the electromagnetic clutch, and when the command switch is operated (
A microcomputer is provided with a vehicle speed storage means for storing vehicle speed data from the vehicle speed sensor when the sensor is turned on or off (ON operation or OFF operation), and a control means for sending commands to each of the drive circuits in response to the difference between the actual vehicle speed and the stored vehicle speed. There was an automatic vehicle speed control device with a built-in configuration. In the automatic vehicle speed control device, by operating a set switch among the command switches, the vehicle speed at the time of the operation is stored in the vehicle speed storage means in the microcomputer, and the difference between the stored vehicle speed and the actual vehicle speed is stored. The control means operates the motor drive circuit and the clutch drive circuit to energize the electromagnetic clutch of the actuator, and the rotation of the actuator drive motor opens and closes the throttle valve via the electromagnetic clutch, thereby driving the actual vehicle. The speed is adjusted to the memorized vehicle speed to perform constant speed driving. Also, when the brake pedal is depressed during the constant speed driving, a cancel signal generated by the brake pedal depression is sent to the microcomputer. input to the control means to release the vehicle speed control state;
The release signal from the 1ji1 means causes the motor drive circuit to stop the rotation of the drive motor in the actuator, and the clutch drive circuit de-energizes the electromagnetic clutch of the actuator to cancel the system. (Problem to be Solved by the Invention) However, in the conventional vehicle speed automatic control device described above, when controlling the vehicle speed, the microcomputer may experience some kind of abnormality due to factors that are almost unthinkable, such as a significantly large overvoltage or unexpected radio wave interference. In some cases, it cannot be said that this will never occur. For this purpose, a microcomputer abnormality detection circuit is provided externally to detect an abnormality in the microcomputer and de-energize the electromagnetic clutch of the actuator to cancel the system.
At this time, if there is an abnormality such as welding of the electromagnetic clutch, and furthermore, if the actuator drive motor is driven in the throttle opening direction due to an abnormality in the microcomputer, the driver will notice the abnormality and press the brake pedal. When you step on it, 17111 forces act,
There is a problem in that when the brake pedal is stopped, the drive motor is driven in the throttle opening direction due to electromagnetic clutch welding. Therefore, if any abnormality occurs in the microcomputer as described above, or if vehicle speed control is canceled,
There is a problem in that it is necessary to de-energize the electromagnetic clutch of the actuator and simultaneously stop the rotation of the actuator's drive motor in the throttle closing direction or stop it. (Object of the Invention) The present invention provides a vehicle speed target that can at least stop the rotation of an actuator drive motor when some abnormality occurs in a microcomputer during vehicle speed control or when vehicle speed control is canceled. The purpose is to provide M control equipment at low cost.

[Structure of the invention]

(Means for Solving the Problems) As shown in the functional block diagram of FIG. 1, the automatic vehicle speed control device according to the present invention includes a vehicle speed sensor 1 that outputs vehicle speed data proportional to the actual vehicle speed, and a cruise command signal that outputs vehicle speed data proportional to the actual vehicle speed. It includes a command switch 2 for outputting, a vehicle speed storage means 3 for storing vehicle speed data from the vehicle speed sensor 1 when the command switch 2 is operated, and a drive motor 4a. A motor-driven actuator 4 that drives the throttle valve 5, a motor drive means 6 that rotates the drive motor 4a of the actuator 4 in forward and reverse directions, a clutch drive means 9 that turns on and off the electromagnetic clutch 4b, and an actual vehicle. In the vehicle speed automatic control device, the vehicle speed storage means 3, the control means 7. The configuration includes a speed increase inhibiting means 8 for inhibiting the rotation of the drive motor 4a in the actuator in the direction of speed increase when each of the drive means 6.9 and the electromagnetic clutch 4b is abnormal or the vehicle speed control is released. The feature is that this configuration is used as a means to solve the conventional problems. (Function of the Invention) The automatic vehicle speed control device according to the present invention has the above-described configuration, so that when an abnormality occurs in the vehicle speed storage means 3, the control means 7, each drive means 6.9, and the electromagnetic clutch 4b, or when the vehicle speed control is canceled. Since the state is detected by the speed increase prohibition means 8, the speed increase prohibition means 8 detects the motor drive means 6 regardless of whether the electromagnetic clutch 4b of the actuator 4 is engaged or disconnected.
This prohibits the drive motor 4a of the actuator 4 from rotating in the speed increasing direction. Therefore, the vehicle speed storage means 3, the control means 7. When an abnormality occurs in each drive means 6, 9 and electromagnetic clutch 4b or when the vehicle speed control state of control means 7 is canceled,
This means that the motor is not driven in the speed increasing direction. (Example) Hereinafter, the present invention will be explained based on the drawings. 2 and 3 are diagrams showing an embodiment of an automatic vehicle speed control device according to the present invention, and FIG. 2 is a diagram showing a circuit configuration of the automatic vehicle speed control device. In FIG. 2, 11 is an automatic vehicle speed control device. This automatic vehicle speed control device 11 includes a vehicle speed sensor 12 (corresponding to the vehicle speed sensor 1 shown in FIG. 1) that outputs vehicle speed data proportional to the actual vehicle speed in the form of a pulse signal, and a command switch 13 (corresponding to the vehicle speed sensor 1 shown in FIG. 1) that outputs a cruise command signal. (corresponding to the command switch 2 shown in Fig. 1) and the vehicle throttle valve 14 (corresponding to the command switch 2 shown in Fig.
A motor-driven actuator 15 (corresponding to the actuator 4 shown in FIG. 1) that drives the throttle valve 5 shown in FIG. , within the controller 20, the vehicle speed sensor 12. Command switch 13 and brake switch 1
Each of the 6 actuation signals is connected to a respective interface circuit 21.
22. A microcomputer 24 that is inputted via 23, and a motor that drives a drive motor 15a of the actuator 15 (described later) in the valve opening direction and valve closing direction (that is, forward and reverse rotation directions) by the microcomputer 24. A drive circuit 25 (corresponding to the motor drive means 6 shown in FIG. 1) and a clutch drive circuit 26 (corresponding to the clutch drive means shown in FIG. 9), and a speed increase prohibition circuit 27a that prohibits the motor drive circuit 25 from driving in the throttle valve opening direction when an abnormality occurs in the microcomputer 24 or when the vehicle speed control is canceled (corresponds to the speed increase prohibition means 8 shown in Fig. gIJ1). , a watchdog circuit 27b that detects a watchdog pulse signal generated during normal operation of the microcomputer 24 and outputs an output signal "1" during normal operation and outputs an output signal 0'' during abnormal operation; and a reset circuit. 28 and a constant voltage circuit 29. The automatic vehicle speed control device 11 has a main switch 30.
Car battery 31. A brake lamp 32 and a cruise lamp 33 are provided outside the controller 20. Further, the command switch 13 includes a set switch, a resume switch, an accelerator switch, and the like. The actuator 15 includes the motor drive circuit 25.
The drive motor 15a is driven in the forward and reverse rotation directions by
(corresponding to the drive motor 4a shown in FIG. 1), and an electromagnetic clutch 15b (corresponding to the drive motor 4a shown in FIG. a fully open position detection limit switch 15c (corresponding to the electromagnetic clutch 4b shown in FIG. A limit switch 15d for fully closed position detection that detects the closed state at the corresponding fully closed position in the actuator 15 (OFF state at the fully closed position), and a motor drive in the valve opening direction when the throttle valve 14 is in the fully closed state. It includes a diode D1 that passes a signal in the forward direction, and a diode D2 that passes a motor drive signal in the valve closing direction in the forward direction when the throttle valve 14 is fully open. Note that the actuator 15 and the throttle valve 14 are connected via an output link or the like. The brake switch 16 includes a first switch 16a that is normally closed and a second switch 16b that is normally open. When the brake pedal (not shown) is depressed, the first switch 16a opens and closes the clutch. While outputting a cancel signal to the drive circuit 26, the second switch 16b
is in a closed state, and a cancel signal is inputted to the microcomputer 24 and the speed increase inhibition circuit 27a via the interface circuit 23. The microcomputer 24 is operated to turn on the set switch of the command switch 13 and
A vehicle speed storage means for storing the vehicle speed at the time of the OFF operation when the F operation is performed (corresponds to the vehicle speed storage means 3 shown in FIG. 1, but it is also possible to store the vehicle speed at the time of the ON operation), and the command switch 13 Among them, in response to the OFF operation of the set switch, the clutch drive circuit 26 is operated to energize the electromagnetic clutch 15b of the actuator 15, and the vehicle speed stored in the vehicle speed storage means is compared with the actual vehicle speed from the vehicle speed sensor 12. A control means (corresponding to the control means 7 shown in FIG. 1) is built-in for controlling the actual vehicle speed to match the stored vehicle speed by operating the motor drive circuit 25 based on the difference. The motor drive circuit 25, as shown in FIG.
In other words, a forward rotation P-channel field effect transistor (hereinafter referred to as rFET) that supplies current in the valve opening direction
J and st,) Ql and the drive motor 15a in the actuator 15 in the reverse rotation direction (i.e., valve closing direction).
P-channel type FETQ2 for reverse rotation that supplies current of
and a motor forward rotation switching unit 25a that operates the FETQI by a motor forward rotation drive signal output from a control means in the microcomputer 24, and a motor reverse rotation drive signal output from a control means in the microcomputer 24. a switching section 25b for reverse rotation that operates the FETQ2; and a forward rotation grounding N-channel type FETQ3 that grounds the drive motor 15a in the actuator 15 and rotates the drive motor 15a in the forward direction when the FETQI is operated. , the FETQ2
When the actuator 15 is operated, the drive motor 1 inside the actuator 15
5a is grounded to reversely rotate the drive motor 15a; resistors R1 and R2 that adjust the input current of the forward rotation switching section 25a; and the reverse rotation switching section. 25b
resistors R3 and R4 for adjusting the input current of the FE;
A resistor R5 that adjusts the gate voltage of TQ3 and the FET
A resistor R6 that adjusts the gate voltage of Q4 and the FETQ
A diode DIO that protects I from back electromotive force, and
A diode Dll that protects ETQ2 from back electromotive force,
Diode D1 that protects the FET Q3 from back electromotive force
2 and a diode D13 that protects the FET Q4 from back electromotive force, and controls the forward/reverse rotation of the drive motor 15a in the actuator 15 in accordance with commands from the microcomputer 24. As shown in FIG. 3, the speed increase prohibition circuit 27a includes a forward rotation prohibition transistor T that is inactivated when the forward rotation switching section 25a of the motor drive circuit 25 is energized.
ri, a forward rotation grounding prohibition transistor Tr2 that is rendered inactive when energized by the forward rotation N-channel type FET Q3 of the motor drive circuit 25, and the transistor Tr2.
an operation inhibiting transistor Tr3 that sets the base voltages of i and Tr2 to "O" when activated; a NOT circuit 40 that inverts the brake signal output from the first switch 16a of the brake switch 16; and an output from the NOT circuit 40. When the signal, the output signal from the watchdog circuit 27b, and the operation signal for actuating the electromagnetic clutch 15b of the actuator 15 by the microcomputer 24 are all "1," the transistor Tr3 is actuated, and any one of the signals is activated. an AND circuit 41 that turns the transistor Tr3 into a non-operating state in the case of “0”;
It has a circuit configuration including resistors RIG to R12. Next, the operation of the automatic vehicle speed control device 11 having the above configuration will be explained. First, in order to operate the automatic vehicle speed control device 11, the main switch 30 is turned on. At this time, the vehicle speed sensor 12 outputs a pulse signal that is vehicle speed data proportional to the actual vehicle speed, and this pulse signal is manually input to the microcomputer 24 in the controller 20 to sample it within a certain period of time, and the number of pulses proportional to the vehicle speed is is recognized by the microcomputer 24. In this state, after a set signal is input to the control means in the microcomputer 24 by the set switch of the command switch 13, the cruise lamp 33 is turned on when the set signal is released, and a pulse signal corresponding to the vehicle speed at that time is turned on. The number is stored in the vehicle speed storage means in the microcomputer 24, and the clutch drive circuit 26 is operated by the control means in the microcomputer 24 to bring the electromagnetic clutch 15b in the actuator 15 into an excited state, and the drive motor in the actuator 15 is activated. 15a allows the throttle valve 14 to be opened and closed. In this state, from the control means of the microcomputer 24,
A motor drive signal corresponding to the number of pulses stored in the vehicle speed storage means is output, and the motor drive signal operates the forward rotation switching section 25a and the forward rotation grounding N-channel type FET Q3 in the motor drive circuit 25. Then, the forward rotation P-channel type FET QI is operated to cause the drive motor 15a in the actuator 15 to rotate forward, and the throttle valve 14 is driven to a predetermined position via the electromagnetic clutch 15b and an output link (not shown) and then held. . After this, even if the accelerator pedal is released, the throttle valve 14 is held at a predetermined position, so that the vehicle can travel at a constant speed. In this automatic vehicle speed control, in order to maintain the set vehicle speed, the control means in the microcomputer 24 controls the number of pulses proportional to the actual vehicle speed of the vehicle speed sensor 12, and the number of pulses is stored in the vehicle speed storage means in the microcomputer 24. It compares the number of pulses (memory vehicle speed), outputs a motor drive signal corresponding to the difference to the motor drive circuit 25, and operates the forward rotation switching section 25a or the reverse rotation switching section 25b in the motor drive circuit 25. At the same time, the forward rotation grounding N-channel type FET Q3 and the reverse rotation grounding N-channel type FET Q4 are operated to rotate the drive motor 15a in the actuator 15 in the throttle valve opening direction or the throttle valve closing direction to keep the vehicle speed constant. keep. Further, at this time, the speed increase prohibition circuit 27a receives the output signal from the watchdog circuit 27b at "1". In addition, since the electromagnetic clutch 15b of the actuator 15 is in an excited state, its actuation signal is "1", and since the first switch 16a of the brake switch 16 is in an OFF state, the brake signal is "1" by the NOT circuit 40.
1”, the output signal from the AND circuit 41 is “1”.
'', the transistor Tr3 is activated, and the operation of the transistor Tr3 causes each transistor Tri. The forward rotation N-channel FET Q3 is operated by the control signal from the microcomputer 24. When the brake pedal is depressed to cancel the vehicle speed control described above, the brake switch is activated in conjunction with the depression of the brake pedal. 16 first switches 16a are in the OFF state (
(normally ON state), and the second switch 16b is turned OFF.
It becomes N state (normally OFF state). At this time, the second switch 1 of the brake switch 16
A cancel signal is input to the microcomputer 24 via the interface circuit 23 due to the ON state of 6b. At the same time, the first brake switch 16
In response to the OFF state of the switch 16a, the speed increase prohibition circuit 2
The brake signal to the AND circuit 41 of 7a is the NOT circuit 4.
0 changes from “1” to “0”, AND circuit 41
Since the output signal from the transistor Tr3 changes from "1" to "0", the transistor Tr3 becomes inactive and each transistor T
rl and Tr2 start operating, and the forward rotation switching section 25a and the forward rotation grounding N-channel type FETQ3
In order to make the drive motor 15a inactive, the drive motor 15a of the actuator 15 is not driven in the throttle valve opening direction, and the drive motor 1 that is rotating in the throttle opening direction is
The rotation of the actuator 5a is stopped without any delay in operation, and the control signal from the microcomputer 24 drives the drive motor 15a of the actuator 15 in the throttle valve closing direction. Also, during the above vehicle speed control, the microcomputer 24
If an abnormality occurs due to overcurrent or radio interference, the watchdog pulse signal from the microcomputer 24 is no longer output, so the output signal of the watchdog circuit 27b changes from 1'' to 0''. Therefore, the output signal of the AND circuit 41 of the speed increase prohibition circuit 27a changes from "1" to "0", so each transistor Tri and Tr2 connects the forward rotation switching section 25a of the motor drive circuit 25 and the forward rotation N channel for grounding. With FETQ3 inactive, actuator 1
This means that the drive motor 15a of No. 5 is prohibited from rotating in the throttle valve opening direction. Therefore, even if an abnormality occurs in the microcomputer 24 during vehicle speed control, the driving motor 15a will not be driven in the throttle valve opening direction due to the influence of the abnormality. Further, when the microcomputer 24 is abnormal, the microcomputer abnormality detection circuit does not work and the electromagnetic clutch 15b of the actuator 15 cannot be de-energized, or when the electromagnetic clutch 15b of the actuator 15 is welded. However, speed increase prohibition circuit 2
Since the drive motor 15a is not driven in the throttle valve opening direction by 7a, acceleration does not suddenly start when the brake pedal is released, and deceleration can be performed according to the driver's will.

【Effect of the invention】

As explained above, the vehicle speed tracking control device according to the present invention includes a vehicle speed sensor that outputs vehicle speed data proportional to the actual vehicle speed, a command switch that outputs a cruise command signal, and a command switch that outputs a cruise command signal. a vehicle speed storage means for storing vehicle speed data from the vehicle speed sensor; a motor-driven actuator that includes a drive motor and drives a throttle valve via an electromagnetic clutch by rotation of the drive motor; and a drive motor for the actuator. Automatic vehicle speed control comprising: a motor drive means for rotating the electromagnetic clutch in forward and reverse directions; a clutch drive means for turning on and off the electromagnetic clutch; and a control means for controlling each of the drive means according to the difference between the actual vehicle speed and the memorized vehicle speed. The device further comprises speed increase prohibiting means for prohibiting rotation of the drive motor in the actuator in a vehicle speed increasing direction when an abnormality occurs in the vehicle speed storage means, the control means, each drive means, and the electromagnetic clutch or when vehicle speed control is released. With this structure, the speed increase prohibiting means prohibits the actuator drive motor from rotating in the throttle valve opening direction, so in the unlikely event that the electromagnetic clutch becomes welded, and furthermore, an abnormality in the vehicle speed storage means, control means, etc. causes the actuator to malfunction. Even if the driver attempts to rotate the throttle valve in the opening direction, at least the actuator is stopped by the speed increase inhibiting means, so that sudden acceleration can be prevented regardless of the driver's intention. Therefore, although the reliability of the system has been significantly ensured in the past, this reliability can be further ensured at a lower cost, which is an excellent effect.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing the basic configuration of an automatic vehicle speed control device according to the present invention, FIG. 2 is an explanatory diagram showing a circuit configuration according to an embodiment of the automatic vehicle speed control device according to the present invention, and FIG.
This figure is a main circuit diagram showing the structure of the motor drive circuit and the speed increase inhibition circuit of FIG. 2. 1.12... Vehicle speed sensor 2.13... Command switch, 3.24... Vehicle speed storage means, 4.15... Actuator, 4a, 15a... Drive motor, 4b, 15b... - Electromagnetic clutch, 5.14... Throttle valve, 6.25... Motor drive means, 7.24... Control means, 8.27a... Speed increase prohibition means, 9.26... Clutch Drive means.

Claims (1)

[Claims] (1) A vehicle speed sensor that outputs vehicle speed data proportional to the actual vehicle speed, a command switch that outputs a cruise command signal, a vehicle speed storage means that stores the vehicle speed data of the vehicle speed sensor when the command switch is operated, and a drive motor. a motor-driven actuator that drives the throttle valve via an electromagnetic clutch by the rotation of the drive motor; a motor drive means that rotates the drive motor of the actuator in forward and reverse directions; and a motor drive means that turns the electromagnetic clutch on and off. In the automatic vehicle speed control device, the automatic vehicle speed control device includes a clutch drive means for controlling the vehicle speed, and a control means for controlling each of the drive means according to the difference between the actual vehicle speed and the stored vehicle speed. 1. An automatic vehicle speed control device comprising speed increase prohibiting means for inhibiting rotation of a drive motor in the actuator in a direction of increasing vehicle speed when an abnormality occurs or when vehicle speed control is canceled.