JPS59229608A - Method for returning moving body to original point - Google Patents

Abstract

PURPOSE:To contract a setting space by detecting a stopper arranged between a moving body and the final end of movement and moving the moving body in the reverse direction up to the original position. CONSTITUTION:The moving body 1 such as a carriage which is to be returned to the original point is moved along a bearing 2 by a motor 3. The turning state of the motor 3 is inputted to a processing control means 7 such as a microcomputer through an encoder 5 to control the driving of the motor 3. The stopper 9 consisting of an elastic substance having prescribed hardness is fitted to the stroke end of the moving body 1. When the moving body 1 collides with the stopper 9, no pulse is outputted from the enocoder 5 and a CPU11 detects the no output state and moves the moving body 1 reversely. When the output of the original zero pulse signal from the encoder 5 is detected, the motor 3 stops driving and the stopped position is used as the original point of the moving body 1.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for returning a movable object to its origin, particularly for use in numerically controlled machine tools, sheet metal processing machines, or industrial robots including playback systems. .

[Technical background of the invention and its problems] In moving objects such as machine tools and industrial robots that require return to origin, dogs and limit switches for indexing the origin are used, for example, as shown in FIG. 1 (A). Return to origin was performed at the operation timing shown in ~(C). In other words, when the limit switch detects the origin dog,
(Fig. 1 (A)), the moving object is moved until a zero pulse is output from the pulse encoder provided to output pulses according to the movement of the moving object (Fig. 1 (B))
, the stopping position of this moving body is the origin (Fig. 1 (C)
)).

By the way, with the recent development of industrial robots, etc., there is a particular demand for reduction in weight and size. However, in order to carry out the above-mentioned conventional method for returning a moving object to its origin, an origin dock and a limit switch are essential, so it is not possible to reduce the space for the valves installed therein. As a result, the above-mentioned reduction in weight and size cannot be achieved.

[Objective and Summary of the Invention] The present invention has been made in view of the above, and an object thereof is to provide a method for returning a movable object to its origin, which allows the installation space to be reduced.

In order to achieve the above object, the present invention is configured such that the movement is set by a movement control means, the movement is detected by a movement amount detection means which outputs a predetermined reference signal every time a certain movement amount is detected, and the movement is caused to return to the origin. A stopper is placed between the required moving object and the end of the movement of the moving object, and when it detects that the moving object hits the stopper, the amount of movement of the moving object in the opposite direction of the hitting direction is determined. The gist of the movable body is to move the movable body until the reference signal is first output from the detection means, thereby setting the movement stop position due to the output of the reference signal as the origin of the movable body.

[Embodiments of the invention] The present invention will be described in detail below with reference to the drawings.

FIG. 2 shows an embodiment of the present invention, where 1 is 1 to 1.
A movable body that requires return to its origin, such as a carriage movable along the bearing 2 such as a Musomba or LM guide, 3 a motor that drives the movable body to move the movable body along the bearing 2;
7 is an encoder that outputs pulses according to the rotation of the motor, and 7 is an encoder that performs predetermined processing (described later) based on the input of the pulses, drives and controls the motor 3, or detects the origin of the moving object 1, for example. Processing control means 9 constituted by a computer is a stopper formed of an elastic body (for example, urethane) having a predetermined hardness and provided at the stroke end of the movable body 1. Note that the processing control means 7 includes a CPU 11°ROM 13. The configuration includes a RAM 15 and an input/output board 17. Further, the torque of the motor 3 is suppressed and controlled to the necessary minimum.

Next, regarding the operation of this embodiment, which is not shown in FIG.
The processing flowchart and (A) to (C) in Fig. 4
The explanation will be based on the operation timer 1 shown in FIG.

The operating body 1 moves toward the stroke end and stops at the stopper 9.
When the moving body 1 collides with the collision direction, the pulse output from the encoder 5 disappears (FIG. 4 (B)). Figure (C)) Outputs a reverse rotation signal to the motor 3 (steps 100 to 120), and then the CPU 11 outputs a reverse rotation signal to the motor 3.
When detecting that the first zero pulse signal is output from the encoder 5 during the movement in the opposite direction, the motor 3 is stopped (Fig. 4 (C)).
)) Steps 130 and 140 to output the signal. That is, the stop position becomes the origin of the moving body 1.

In this embodiment, the stopper is made of an elastic body, but a limit switch may be used instead, and the motor may be reversed by outputting the switch signal.

[Effects of the Invention] As explained above, according to the present invention, the movement amount detection means outputs a predetermined reference signal every fixed movement amount.
A stopper is placed between the moving body whose position is controlled based on PIJm detection and the end of the movement of the moving body, and when it is detected that the moving body hits the stopper, the moving body is moved in the direction of the collision. The moving body is moved in the opposite direction, and when the reference signal is output for the first time, the moving body is stopped, and the stopped position is referred to as the origin position of the moving body, so J3 is different from the conventional method.
This eliminates the need for a home position dog and a limit switch, which were required in the conventional method, thereby reducing the installation space, which in turn contributes to the reduction in weight and size of industrial robots using this method.

[Brief explanation of drawings]

Fig. 1 is a conventional example of a method for returning a movable object to its origin, Fig. 2 is an embodiment of the present invention, Fig. 3 is a sheet diagram of the operation 70 in Fig. 2, and Fig. 4 is an operation shown in Fig. 2. This is a timing chart. (Brackets 1 to 1 mark the main parts of the figure. Explanation of symbols) 1
...Moving body 3...Motor 5...Encoder 7...Processing control means 9...Stopper Fig. 3 Fig. 4 Appetizing movement

Claims (1)

[Claims] A moving body that is moved by a movement control means, is detected by a movement amount detection means that outputs a predetermined reference signal every time a certain amount of movement is detected, and is required to return to its origin, and the end of the movement of the movement object. A stopper is arranged between the moving body and the stopper, and when it is detected that the moving body hits the stopper, the first reference signal is outputted from the movement amount detecting means in a direction opposite to the collision direction of the moving body. A method for returning a movable body to an origin, characterized in that the movement stop position determined by the output of the reference signal is set as the origin by moving the movable body until the reference signal is output.