JPH11285295A - Controller for actuator of damping force adjusting type hydraulic bumper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely hold the rotational position of an actuator and to prevent the heating of a stepping motor, i.e., of the actuator by providing a rotational- position holding means, wherein when the actuator is in a stopping state the actuator is so excited intermittently at a predetermined period that the actuator holds its stopping position. SOLUTION: Drive pulses CK are outputted until the rotational position of a stepping motor 5, i.e., of an actuator coincides with the rotational-position command value fed from a controller 1. In the state after this operation, the current application (excitation) for holding the rotational position of the stepping motor 5 is performed intermittently at a predetermined period, responding to the signal fed from an oscillator 14. Therefore, even though the fluidic force applied to a hydraulic bumper, etc., are applied to the stepping motor 5 via a control rod, the loss of the synchronism of the actuator, i.e., of the stepping motor 5 is prevented by its intermittent current applications performed for each predetermined period. As a result, while the accuracy of the variable damping-force control of the hydraulic bumper is secured, the heating of the stepping motor 5 is prevented to make its durability secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an actuator for changing a damping force of a hydraulic shock absorber.

[0002]

2. Description of the Related Art Conventionally, there has been known a hydraulic shock absorber capable of changing a damping force according to a driving condition of a vehicle. In such a hydraulic shock absorber, a step is provided on a control rod inserted through an inner periphery of a piston rod. The output shaft of an actuator such as a motor is connected, and the damping force is changed according to the rotational position of the output shaft.

As shown in FIG. 5, when an angle command value from a controller (not shown) changes, the output shaft is rotated so that the angle of the actuator coincides with the command value, so that energization to the actuator is started. Then, when the rotation angle of the output shaft matches the angle command value of the controller, the power supply to the actuator is cut off.

[0004]

However, in the above-mentioned prior art, after the rotational position of the actuator coincides with the angle command value from the controller, energization is interrupted, and this position is held only by the holding torque of the actuator. However, if the fluid force applied to the hydraulic shock absorber is applied to the actuator via the control rod, and the holding torque of the actuator is smaller than the force due to the fluid force, etc., the actuator which should be stopped will rotate and step out. There was a problem of causing.

In order to surely prevent the step-out, it is conceivable to continuously energize the actuator to maintain its position even after the actuator is driven. In some cases, the coil of the actuator was overheated and the durability was impaired.

The present invention has been made in view of the above problems, and has as its object to prevent the actuator from overheating while reliably maintaining the rotational position of the actuator.

[0007]

According to a first aspect of the present invention, there is provided an actuator for driving a hydraulic shock absorber capable of changing a damping force, and a control means for driving the actuator to set a damping force. In the actuator control device for a hydraulic shock absorber, the control unit includes a rotation position holding unit that excites the actuator so as to intermittently hold the position of the actuator at a predetermined cycle when the actuator is stopped.

In a second aspect based on the first aspect, the rotational position holding means excites the actuator for a predetermined period shorter than a predetermined period.

[0009]

Therefore, according to the first aspect, when the actuator is stopped, the excitation for maintaining the rotational position is performed intermittently at a predetermined cycle, so that the fluid force applied to the hydraulic shock absorber is controlled. Even if it is applied to the actuator via the rod, it prevents the actuator from rotating and stepping out due to intermittent excitation at predetermined intervals,
At the same time as ensuring the accuracy of the damping force variable control, the excitation is performed intermittently, so that the actuator is prevented from overheating and the durability of the actuator is prevented from lowering.

According to a second aspect of the present invention, the excitation for maintaining the rotational position is performed at a predetermined period and for a predetermined period shorter than the period. It is possible to maintain the rotational position without lowering the durability of the device.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, an output shaft of an actuator constituted by a control rod 3 inserted into the inner periphery of a piston rod 6 and a step motor 5 is provided at the upper end of the hydraulic shock absorber 2 of which damping force can be changed. The damping force of the hydraulic shock absorber 2 is changed according to the rotational position of the output shaft 4.

The controller 1 includes a sensor 20 (for example,
A damping force is determined based on a detection value from the acceleration sensor), and a drive command value (pulse) is output to the step motor 5 so that the rotational position of the control rod 3 becomes a position corresponding to the damping force.

Here, as shown in FIG. 2, the controller 1 is mainly composed of a microcomputer, and calculates a rotational position command value of the step motor 5 based on a detection value of the sensor 20, and also generates a drive pulse CK. And a control unit 11 for calculating and outputting the rotation direction U / D, an oscillator 14 for transmitting a signal of a predetermined period, and an OR for outputting a logical sum of a conduction output on / off1 from the control unit 11.
The gate 13, these driving pulses CK, the rotational direction U / D
And a driver section 12 for controlling the excitation of the step motor 5 according to the output of the OR gate 13.

When the pulse cycle from the drive pulse CK from the control section 11 is, for example, 5 to 6 msec, as shown in FIG. 3, the signal from the oscillator 14 is turned ON for 5 msec at a cycle of, for example, 50 msec. Is set to be always output and the ON time is a predetermined period sufficiently shorter than the cycle.

The energization output on / off1 from the control unit 11 corresponds to the drive pulse C based on the rotational position command value.
While it is ON while K is being output, it is OFF while no drive pulse CK is being output.

Accordingly, the energization output ON / OFF output from the driver unit 12 to the step motor 5 is a period during which one of the energization output on / off1 from the control unit 11 and the signal from the oscillator 14 is ON, and , Oscillator 1
4 only when the signal is ON (power output on / off1 is O
In FF), the excitation output to the step motor 5 is only energization for maintaining the rotational position, and the excitation for rotation of the step motor 5 is not performed.

Therefore, in the stop state after the drive pulse CK is output until the rotational position of the step motor 5 matches the rotational position command value from the controller 1, the oscillator 14 is energized to maintain the rotational position. Therefore, even if a fluid force or the like applied to the hydraulic shock absorber is applied to the step motor 5 via the control rod 3, the step motor 5 is disconnected by the intermittent energization at a predetermined cycle. In this way, it is possible to prevent the step motor 5 from being overheated by intermittent energization while ensuring the accuracy of the damping force variable control while preventing the adjustment, thereby ensuring the durability.

FIG. 4 shows a second embodiment, and is a flowchart showing an example of control when the controller 1 of the first embodiment holds the rotational position by software. This flowchart has a predetermined period. It is executed every time, for example, every 5 msec.

First, in step S1, it is determined whether or not the rotational position command value is the same as the above value. If the rotational position command value is the same, it is determined that the step motor 5 is stopped, and the rotation after step S2 is performed. While the process proceeds to the position holding control, if they are not the same, it is determined that the step motor 5 is being driven, and the process is terminated as it is.

In step S2, a predetermined value (for example, a value corresponding to the control cycle = 5) is added to the counter CNT. Then, in step S3, it is determined whether or not the counter CNT has reached the predetermined value T. Is used to determine whether a predetermined time has elapsed since the previous excitation output to the step motor 5, and the predetermined value T is set to, for example, 50 or the like.

If the counter CNT has reached the predetermined value T, the process proceeds to step S4, in which a pulse for holding the rotational position of the step motor 5 (hereinafter, referred to as a position holding pulse) is output. CNT is a predetermined value T
If it is less, the process ends.

The position holding pulse output in step S4 is set in advance so as to be ON for a short predetermined period such as 5 msec, for example, similarly to the signal from the oscillator 14 of the first embodiment. .

After outputting the position holding pulse, the counter CNT is reset to 0 in step S5, and the process is terminated.

By repeating the above processing at a predetermined cycle = 5 msec, the energization output ON / OFF shown in the first embodiment is performed.
Similarly to the above, when the drive pulse for rotating the step motor 5 ends, a predetermined period (5
Every 0 msec), a position holding pulse is output for an extremely short time such as 5 msec, so that the rotational position can be held reliably.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a schematic configuration diagram of an actuator control device of a damping force adjusting type hydraulic shock absorber.

FIG. 2 is a schematic configuration diagram of a controller.

FIG. 3 is a time chart of each signal of a controller.

FIG. 4 is a flowchart illustrating an example of position holding control performed by a controller according to the second exemplary embodiment.

FIG. 5 is a time chart showing a conventional excitation operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Controller 2 Hydraulic shock absorber 3 Control rod 4 Output shaft 5 Step motor 6 Piston rod 11 Control part 12 Driver part 13 OR gate 14 Transmitter 20 Sensor

Claims (2)

[Claims] 1. An actuator control device for a damping force-adjustable hydraulic shock absorber, comprising: an actuator for driving a hydraulic shock absorber capable of adjusting a damping force; and control means for setting the damping force by driving the actuator. The control means, when the actuator is in a stopped state,
An actuator control device for a damping force-adjustable hydraulic shock absorber, comprising: a rotation position holding means for exciting the actuator so as to intermittently hold the position of the actuator at a predetermined cycle. 2. The actuator control device according to claim 1, wherein the rotation position holding unit excites the actuator only for a predetermined period shorter than a predetermined period.