JPS6282408A - Position controller - Google Patents

Abstract

PURPOSE:To control the position with a high precision by detecting the position of a coupling member driven with driving means and driving a damping means with a driving control means to damp it. CONSTITUTION:A bias spring 1, a wire (coupling member) 2 wound around a pulley 4, and a spring (driving means) 3 consisting of a shape memory alloy are connected in series to constitute a position controller, and the driv-means 3 is heated and cooled by a heating and cooling device 5 to control the position of the pulley 4. In this case, a position sensor 6 consisting of a potentiometer, a setter 7 which sets optionally the extent of rotation of an arm 4a of the pulley 4, a comparator 8, a damping device driver (driving control means) 9 are provided, and a damping device 10 is driven on a basis of the signal from the comparator 8. The movement of a wire 2 is detected by the position sensor 6 and is compared with a set value by the comparator 8; and when the difference is zero, the damping device 10 is driven and the heating and cooling device 5 is stopped to control the position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a position control device for controlling the position of a driven body coupled to an air cylinder or the like made of a shape memory alloy spring.

[Conventional technology]

Conventionally, as a position control device, one shown in FIG. 2 is known. In the figure, 1 is a bias spring (9a body)
, 2 is a wire (coupling member) wound around a pulley (driven body) 4 to be described later, 3 is a spring (driving means) made of a shape memory alloy that is memorized to contract when heated, and the bias spring l, A wire 2 and a shape memory alloy spring 3 are connected in series in this order so that the wire 3 is always under tension.
One end of the bias spring 1 and the shape memory alloy spring 3 are each fixed. The pulley 4 is pivotally supported so as to be able to rotate twice, and its peripheral surface is wound with a plurality of endless windings by the wire 2. 4a is an arm portion provided on a part of the side surface of the pulley 4. 5 is a heating and cooling device for heating and cooling the spring 3 made of the shape memory alloy.

The conventional position control device is configured as described above, and when the shape memory alloy spring 3 is heated by the heating/cooling device 5, the spring 3 is compressed by the heat, and as a result, the bias spring 1 is 2, the wire 2 moves in the direction of the shape memory alloy spring 3. For this reason,
The arm 4a provided on the pulley 4 rotates counterclockwise in FIG. 2 from the home position and stops LI= at an angle corresponding to the contraction of the shape memory alloy spring 3.

[Problem that the invention seeks to solve]

However, such position control devices depend on the stopping accuracy of the driving means, so if high stopping accuracy is required, driving means with low stopping accuracy such as shape memory alloy springs cannot be used. There was a problem.

In addition, high-output drive means with high stopping accuracy generally have to be large in size.

[Means for solving problems]

The purpose of this invention is to provide a compact position control device that is capable of high-precision position control using a drive f-stage with low stopping precision, and that also has the ability to arbitrarily set a stop position. When the position of the coupling member driven by the drive means is detected, the drive control means drives the braking means to brake the coupling member.

〔Example〕

An embodiment of the present invention will be described based on FIG. In addition,
The same parts as those of the conventional example are given the same reference numerals and the explanation will be omitted.

Reference numeral 6 denotes a position sensor composed of a potentiometer, which detects continuous displacement of the wire 2. Reference numeral 7 denotes a setting device for arbitrarily setting the amount of rotation of the arm 4a, and 8 is a comparator for comparing the signal from the position sensor 6 and the setting signal from the setting device 8. A brake device driver (drive control means) 9 drives the brake device (M stage) 10 based on the signal from the comparator 8.

The braking device 10 grips the wire 2 and applies a brake to the wire 2. A heating/cooling device driver 11 drives the heating/cooling device 5 based on a signal from the comparator 8.

Next, the effect will be explained.

When the shape memory alloy spring 3 is heated by the heating/cooling device 5, the spring 3 contracts due to the heat, and as a result, the bias spring 1 is pulled and expanded via the wire 2.

Then, the arm 4a provided on the pulley 4 rotates counterclockwise from the home position in Fig. wS1. Movement of the wire 2 is continuously detected by a position sensor 6 and compared with a set value set by a setting device 7 by a comparator 8.

When the deviation between the set value and the signal from the position sensor 6 becomes zero, the comparator 8 drives the braking device 5 to apply braking to the wire 2, stops the rotation of the pulley 4, and at the same time controls the heating/cooling device driver 10. The heating of the heating/cooling device 5 is stopped through.

After the shape memory alloy spring 3 is cooled, when the braking by the braking device 10 is released, the bias spring 1 causes the arm 4a to rotate clockwise in FIG. Return to home position.

〔Effect of the invention〕

Since the present invention has the above-described configuration, there is an advantage that even if a driving means with low stopping precision is used, arbitrary variable position control can be performed with high precision.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a conventional example. In the figure, 1 is a bias spring, 2 is a wire, 3 is a shape memory alloy spring, 9 is a brake device driver, and 10 is a brake device.

Claims (1)

[Claims] A driving means for driving an elastic body having one end fixed via a coupling member, a braking means for braking the coupling member, and a drive for controlling the braking means by detecting a signal from a position sensor provided on the coupling member. A position control device comprising: a control means, and controlling the position of a driven body provided on the coupling member.