JPH0565372B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle speed control device for an automobile such as a constant speed traveling device.

[Background Art] Devices are already known that include an actuating device that drives a speed adjustment member of an automobile and control this actuating device by electric signals from an electronic control device such as a constant speed cruise control device or a follow-up cruise control device. ing. In such a device, the actuating device is preferably small and lightweight, and for example, a DC motor called a two-brush motor is required. Generally, a two-brush motor has two power supply terminals, and the direction of operation is opposite depending on the direction of the direct current applied to the terminals.

By the way, in this type of control device, if the actuating device operates abnormally due to a cause in the electronic control device or the wiring, it will seriously impede the driving function, so it is necessary to provide a safety device to monitor abnormalities in the actuating device. desirable. In this case, monitoring for anomalies is
It is necessary to consider the direction of the current applied to the actuating device. For example, it is determined that there is an abnormality only when a current is continuously applied in a certain direction for a set time or longer.

However, in an actuating device having two power supply terminals, such as a two-brush motor, the direction of the current changes alternately during control, so it has been difficult to monitor abnormalities in consideration of the direction of the current.

[Object of the Invention] In view of the above problems, the present invention makes it possible to monitor abnormalities in the device by taking into account the direction of the current supplied to the actuating device of the type having two power supply terminals. The purpose of this invention is to provide a vehicle speed control device for automobiles.

[Structure of the Invention] Therefore, in the present invention, an optical coupler including a one-way current-carrying element between two lines connecting two power supply monitoring or drive circuits of the actuating device and a power feeding terminal is connected in parallel with the actuating device. The present invention is characterized by comprising an evaluation means for determining whether or not the electrical signal obtained by the optical coupling element is continuously supplied to the two power supply terminals for a predetermined period of time or longer.

As the optical coupler, a so-called photocoupler can be used. This optical coupler generates an electrical signal in response only to the direction of the current to be monitored among the currents output from the drive circuit. Therefore, when monitoring an abnormality only when the speed governing member is driven by the actuating device in the direction of speed increase, the optical coupler can be made to respond only to the direction of the current corresponding to speed increase. When monitoring both directions of current, two optical couplers may be used.

The evaluation means are arranged in an embodiment to determine whether the electrical signal obtained by the optical coupler simply exceeds a predetermined fixed time. If necessary, it may be determined whether the electrical signal corresponds to a more complicated preset energization pattern.

The evaluation means may be provided independently of the electronic control device such as the constant speed cruise control device described above, or may be built into the electronic control device. The results of the evaluation should be displayed to the occupants, act on the electronic control device to control the device in a safe manner, or shut off between the electronic control device and the actuating device, or control the actuating device and the device. It can be used to cut off the speed member.

[Operation and Effect] With the above configuration, the current supplied from the drive circuit to the actuating device via the power supply terminal is also supplied to the optical coupler connected in parallel with the actuating device. The evaluation means for determining whether the electric signal obtained by I'll keep an eye on it to see if it changes.

Therefore, based on the evaluation result of the evaluation means, it is possible to detect whether or not the actuating device is operating abnormally by supplying current from the drive circuit to the actuating device.

[Example] Fig. 1 shows an outline of a constant speed traveling device for an automobile to which the present invention is applied. The actuating device 1 is selectively connected to a speed regulating member (not shown) of the traveling engine 3 (for example, a throttle valve) via an electromagnetic clutch 2.
When the electromagnetic clutch 2 is in the engaged state, the engine 3 is activated by the actuating device 1.
The rotational speed of the vehicle is reversibly increased or decreased, and the vehicle speed is increased or decreased by a traveling device 4 coupled to the engine 3.

The actuation device 1 is adapted to receive an actuation signal from an electronic control device 5 for constant speed driving control,
The electronic control device 5 applies a connection signal to the electromagnetic clutch 2 from the time the start switch 6 is turned on until the stop switch 7 is turned on, and the vehicle speed signal obtained from the vehicle speed detector 8 is set to a value indicating the target vehicle speed. An increase/decrease signal is provided to the actuating device 1 so as to comply with the above.

FIG. 2 shows the configuration of the electronic control device 5. As shown in FIG. In this figure, the actuating device is illustrated as a DC motor 10. The electric motor 10 has two power supply terminals 10A and 10B, and these terminals are connected to an output terminal of a motor drive circuit 12 that switches the current direction in response to an output command from a microcomputer 14. The microcomputer 14 is connected to several input devices including a vehicle speed sensor and an operation switch, and executes a preset constant speed running control program. This control program is already known.

The microcomputer 12 has a normally open relay 16
It is now possible to give control signals to people as well.
The contacts of the normally open relay 16 are connected in series with the normally closed relay contacts 18 to a circuit that connects the electromagnetic clutch 2 to the vehicle power source.

A photocoupler 20 as an optical coupler is connected to the line connecting the power supply terminals 10A, 10B of the DC motor 10 and the motor drive circuit 12 in parallel with the motor 10, and the power supply terminal 10A is connected to the motor 10.
The wire 21 is wired so as to be at the ground level only when current flows in the direction from the terminal 10B to the terminal 10B (this is defined as the speed increasing direction).

A timer circuit 22 is provided as an evaluation means in response to the potential of line 21. Timer circuit 2
2, when the potential of the line 21 reaches the ground level and a preset period of time has elapsed, the normally closed relay contact 18 is opened and maintained in the open state.

The set time in the timer circuit 22 is, for example,
It can be set to an appropriate value that is longer than the time required to move the entire stroke when the speed regulating member is driven in the speed increasing direction.

In the device configured as described above, when constant speed running control is performed, if there is no abnormality in the microcomputer 14, motor drive circuit 12, power supply terminal wiring, and optical coupler 20 and wire 21, the Closed relay contact 18 is closed. The normally open relay 16, driven by the microcomputer 14, is closed and the electromagnetic clutch 2 is energized into the connected state. The microcomputer 14 compares the target vehicle speed with the actual vehicle speed, determines whether to drive the speed-governing member in the speed-increasing direction, decelerating direction, or stopping it, and drives the motor in accordance with the result of the determination. The output command of the circuit 12 is given to drive the DC motor 10 reversibly.

If an abnormality occurs and the current continues to flow in the speed increasing direction, the output line 21 of the optical coupler 20 continues to be at the ground level. The timer circuit 22 responds to this, and when the set time has elapsed, the normally closed relay 18
to open. Therefore, the electromagnetic clutch 2 is disconnected and prevents the direct current motor 10 from driving the regulating member out of alignment. Since the speed regulating member is normally provided with a return spring, the speed regulating member moves in the direction of deceleration when the electromagnetic clutch 2 is disconnected.

Thus, when an abnormality occurs, the constant speed driving control is canceled and abnormal driving of the vehicle is prevented.

FIG. 3 shows the configuration of another embodiment of the electronic control device including safety means. In this example, the electromagnetic clutch 3 is connected to the power supply via one normally open relay 16 controlled by a microcomputer 14. The normally open relay 16 is controlled by a microcomputer 14 which also executes an evaluation program. For this purpose, the output line 21 of the optical coupling arrangement 20 is connected to the microcomputer 14 as an input.

The microcomputer 14 executes a known constant speed running control program and also executes an evaluation program shown in FIG. 4 at regular intervals.
For example, the evaluation program is executed as a subroutine program accepted by a timer interrupt.

In step 24 of the evaluation program, it is determined whether constant speed running control is being performed, for example, based on whether or not the normally open relay 16 is energized. Next, in step 25, it is determined based on the potential of the line 21 whether or not a current in the speed increasing direction is being supplied.
Increment the timer count value with . The result is determined in step 27, and step 28 is executed when a value corresponding to a preset time is reached. In step 28, a deenergizing command is given to the normally open relay 16, thereby disconnecting the electromagnetic clutch 2 and stopping the driving of the speed regulating member. The deactivation command at step 28 cannot be deactivated by any other constant speed cruise control program unless the power to the device is once shut off. Note that if the current disappears when the time during which the current in the direction of speed increase is supplied is less than the set time, the determination result in step 25 becomes "no" and the timer count value is cleared to zero in step 29. be done.

In this way, the initial object of the present invention can also be achieved by incorporating the evaluation means into the microcomputer 14.

In addition, in the constant speed running control program of the microcomputer 14, the current supply time in the direction of speed increase is made so that it does not continuously exceed a certain set time (which may be longer than or equal to less than the full stroke of the speed regulating member). By programming, the timer count value in the evaluation program can be determined in accordance with that value.

The technical idea of the present invention is not limited to the embodiments described above, but is modified based on the gist stated in the claims and taking into consideration the suggestions described in the section of the background art and the summary of the structure of the invention. Needless to say, it allows for

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an overview of a constant speed traveling device to which the present invention is applied, FIG. 2 is an electrical wiring diagram showing one example of the configuration of the electronic control device in FIG. 1, and FIG. FIG. 4 is an electrical wiring diagram showing another example of the configuration of the electronic control device shown in FIG. 1, and FIG. 4 is a flowchart showing an evaluation program executed by the microcomputer shown in FIG. 1... Actuation device, 2... Electromagnetic clutch, 3...
A running engine including a throttle valve as a speed regulating element, 5... an electronic control device, 10... a DC motor serving as an actuating device, 10A, 10B... power supply terminals,
12... Motor drive circuit, 14... Microcomputer, 16... Normally open relay, 18... Normally closed relay, 20... Photocoupler forming an optical coupler,
21... line, 22... timer circuit serving as evaluation means.

Claims (1)

[Claims] 1. An actuator having two power supply terminals, the operating direction of which is opposite depending on the direction of the direct current supplied to the terminals, and a drive circuit that supplies current to the power supply terminals. In the vehicle speed control device for an automobile, the actuating device drives a speed regulating member of the automobile, wherein the actuating device is connected between the two power supply terminals or two lines connecting the drive circuit and the power supply terminal in parallel with the actuating device. an optical coupling element including a one-way current-carrying element connected to the optical coupling element; and an evaluation means for determining whether an electrical signal obtained by the optical coupling element is continuously supplied to the two power supply terminals for a predetermined period or more. A vehicle speed control device for an automobile, comprising: