JPS6219709A - Position detector for body of rotation - Google Patents

Abstract

PURPOSE:To eliminate a dead angle of a body of rotation by providing a switch which changes when the body of rotation rotates in excess of 360 deg. from the reference position in cutting off a power source and maintains the state, and returning the body of rotation to the reference position. CONSTITUTION:A dog 8 is fixed on a different place from a tip 6 for detection of a flange 5 and the switch 9 which is opened and shut in opposition when the flange 5 rotates in excess of about 360 deg. from the reference position is provided on the dog 8. Then, a signal from a sensor 7 for detecting the reference position and a signal from the switch 9 are once take in a buffer aregister. These signals are read and processed with a controller such as a microprocessor, and a motor 1 is controlled so that when the flange 5 rotates more than one rotation, it is rotated more than one rotation and returned to the reference position. Accordingly, the cutting-off of the power source or a hose can be prevented and a working range of the body of rotation is taken 360 deg. and the deal angle of the body of rotation can be eliminated.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a position detection device for a rotary body such as a rotary shaft of an industrial robot, and particularly for detecting the rotational position of a rotary shaft when positioning is performed before or after one rotation. The present invention relates to a rotating body position detection device suitable for use in detecting.

<Conventional technology> Conventionally, the rotational position detection device for industrial robots is
It has a configuration as shown in the figure, and includes a motor l, a rotation detector such as a rotary encoder 2, a flange 5 for attaching a driven object, and a cup for connecting the motor l and the rotating shaft 4 of the flange 5. A sensor 7 for detecting the reference position of the flange 5, which is located on one side of the flange 5 and faces the sensor 7 when the flange 5 is in the reference position. Equipped with chip 6. Then, the motor 1 is rotated, and its rotation angle is detected by a low-resolution encoder 2, and servo control is thereby performed to perform precise positioning. As mentioned above, the sensor 7 is for determining the reference position, that is, the origin, and is turned on when the sensor 7 faces the detection chip 6, so that the absolute reference position is detected.

By the way, in the conventional rotating body position detection device described above, when the power is turned off, the absolute position data based on the output of the rotary encoder 2 disappears, and the reference position is detected again using the detection chip 6 and the sensor 7. However, if the rotating shaft 4 has rotated more than one revolution, for example, 1.2 revolutions, during the reference position return operation, it must rotate 02 revolutions to return to the reference position, and then 1.2 revolutions to return to the reference position. I can't. In other words, with the conventional rotating body position detection device, it is not possible to distinguish between the case where the rotating body has rotated more than one rotation from the reference position and the case where the rotating body has rotated less than one rotation when the power is turned off. On the other hand, attach a jig to the flange 5,
When this jig is driven electrically, pneumatically, or hydraulically, electric wires and hoses are connected to the jig, but each time the power is turned off, as mentioned above, for example! , instead of returning to the reference position after two rotations, it returns to the reference position after 0.2 rotations, resulting in a deviation of one rotation, which is accumulated. In this way, conventionally, each time the power is turned off, the number of revolutions (36
There was a fear that the misalignment would occur by an integer multiple of 0°, which would accumulate and cause the wire or hose to break.

In order to avoid such a phenomenon, if the range of the rotation angle of the rotation axis is defined, the rotation angle cannot be more than 360 degrees due to variations in sensor sensitivity, etc., and is limited to about 340 degrees at most. If this rotary shaft is used to control the attitude of the tip of a robot or the like, a blind spot will occur, resulting in the problem that the attitude cannot be fully controlled.

<Object of the Invention> Therefore, the object of the present invention is to make it possible to identify whether the rotating body is rotating within one rotation or exceeding one rotation when the power is turned off. The objective is to ensure that the rotating body returns to the standard position by rotating the specified angle, eliminating the risk of disconnecting the power supply, hoses, etc., and allowing the operating range to extend beyond 360°, eliminating blind spots of the rotating body. .

<Structure of the Invention> In order to achieve the above object, the present invention provides a rotating body position detection device including a rotating body driven by an actuator and a sensor for detecting a reference position of the rotating body, in which the rotating body is It is characterized by the provision of a switch that is switched when rotated beyond 360° from the reference position and maintains the switched state.

<Example> Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

In Figure 1.2, ■ is a motor, 2 is a low-return encoder, 3 is a decelerator, 4 is a rotating shaft as a rotating body, 5 is a flange, 6 is a detection chip, and 7 is a sensor for detecting a reference position. These have exactly the same configuration as the conventional example shown in FIG. 7.8.

A dog 8 is fixed on one side of the flange 5 provided with the detection chip 6 at a location different from the detection chip 6.
A switch 9 is provided oppositely to open and close when the flange 5 rotates approximately 360 degrees from the reference position. As shown in FIG. 3, the switch 9 includes a substantially crescent-shaped operating member 9b whose center is swingably supported on a fulcrum 9a. When the flange 5 passes the switch 9 in the direction of the arrow X in FIG. On the other hand, when the dog 8 passes the open position of the switch 9 to the left from the broken line in FIG. The switch 9 is held in a closed state by rotating it counterclockwise. That is, when the flange 5 rotates beyond 360° from the reference position within 360° (normal rotation), the switch 9 switches from closed to open as shown by the solid line in FIG. Flange 5
When it rotates from a reference position from a rotation angle of 360 degrees or more to a rotation angle of less than 360 degrees (during reverse rotation), the switch is switched from open to closed as shown by the broken line in FIG. The hysteresis shown in FIG. 4 occurs because the dog 8 presses the right or left end of the crescent-shaped actuating member 9b in response to forward or reverse rotation of the flange 5.

The outputs from the switch 9 and sensor 7 are processed as shown in FIG. That is, the signal from the sensor 7 for detecting the reference position and the signal from the switch 9 are once taken into the buffer register IO, and these signals are read by a control device 11 such as a microprocessor.
Even if the flange 5 has been rotated by one rotation or more as a result of processing as shown in FIG. 6, the motor 1 is controlled so as to rotate the flange one rotation or more and return to the reference position.

In the above configuration, as shown by arrow (A) in FIG. 4, the power is turned off with the flange 5 rotated one or more revolutions, and then the flange 5 is rotated one or more revolutions to return to the standard position. shall be.

The control device 11 shown in FIG. 5 receives the output of the switch 9 and the output of the sensor 7 from the buffer register 10, and performs the control procedure shown in FIG.

First, check whether the switch 9 is "open" or "closed". If it is "open", the motor 1 is rotated in the reverse direction, and if the rotation angle is within 360 degrees and it is "closed", the sensor 7 is " Check whether it is "on" or "off". If it is "off", the motor l is further rotated, and if it is "on", it means that the reference position (origin) has been detected. In this way, even if the flange 5 has rotated one or more revolutions, it can be rotated one or more revolutions and then returned to its original position. At this point, it is also possible to use the zero signal of the low-resolution encoder 2 to locate the origin with even higher precision.

In the above embodiment, as a sensor for detecting the reference position,
Although a photoelectric sensor is used, a magnetic sensor may also be used, or the row encoder 2 itself may be used to detect the reference position using its zero signal. Furthermore, the detection chip 6 and the dog 8 may be the same.

<Effects of the Invention> As is clear from the above, according to the present invention, when the rotating body rotates more than 360° from the reference position, the switching occurs.
Since a switch is provided to maintain the switched state, it is possible to identify whether the rotating body is rotating within 360° or rotating over 3600°. Therefore, it is possible to rotate the rotating body by more than 360° and return it to the reference position. It is possible to prevent the power supply or pose from being disconnected, and it also allows the rotating body to have an operating range of 360 degrees or more, eliminating blind spots of the rotating body.
I can kill.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is a view from the ■-■ arrow in FIG. 1, FIG. 3 is an enlarged view of the switch, and FIG. 4 is a diagram explaining the hysteresis of the switch. Fig. 5 is a circuit diagram of a circuit for detecting the reference position, Fig. 6 is a flowchart for detecting the reference position, Fig. 7 is a front view of the conventional example, and Fig. 8 is a circuit diagram of the circuit for detecting the reference position.
It is a view taken along the ■-■ arrow in the figure. l...Motor, 2...Low reencoder, 4...
・Rotating shaft, 5... flange, 7-... sensor, 9... switch.

Claims (1)

[Claims] (1) In a rotating body position detection device that includes a rotating body driven by an actuator and a sensor that detects a reference position of the rotating body, switching occurs when the rotating body rotates more than 360° from the reference position. A rotating body position detection device characterized by comprising a switch that maintains a switched state.