Position detection system and actuator

Abstract

This position detection system includes a primary encoder for a motor shaft, and a secondary encoder for an output shaft of a speed reducer. The secondary encoder includes a first circuit that detects an absolute angle within one rotation of the output shaft, and a second circuit that detects multiple rotations of the output shaft. The position detection system includes an auxiliary battery that supplies current only to the second circuit of the secondary encoder when no current is supplied from outside.

Claims

1. A primary encoder that detects the position of the motor shaft, A secondary encoder for detecting the position of the output shaft of a reduction gear coupled to the motor, The secondary encoder is equipped with a first circuit for detecting the absolute angle within one rotation of the output shaft and a second circuit for detecting multiple rotations of the output shaft, A position detection system comprising: a backup battery that supplies current only to both the first circuit and the second circuit of the secondary encoder when no external current is supplied to the primary encoder and the secondary encoder, wherein the backup battery does not supply current to the detection unit of the primary encoder.

2. The position detection system according to claim 1, wherein the auxiliary battery is charged when current is supplied from an external source to the primary encoder and the secondary encoder.

3. The position detection system according to claim 1 or 2, wherein when no external current is supplied to the primary encoder and the secondary encoder, and the secondary encoder is supplied with current by the backup battery, the secondary encoder performs detection intermittently at a lower frequency than when an external current is supplied to the secondary encoder.

4. The position detection system according to claim 3, wherein the intermittent period during intermittent detection decreases as the rotational speed of the output shaft increases.

5. Motor and, A reduction gear coupled to the motor, A primary encoder for detecting the position of the motor shaft of the motor, A secondary encoder for detecting the position of the output shaft of the reduction gear, The secondary encoder is equipped with a first circuit for detecting the absolute angle within one rotation of the output shaft and a second circuit for detecting multiple rotations of the output shaft, An actuator comprising: a spare battery that supplies current only to both the first circuit and the second circuit of the secondary encoder when no external current is supplied to the primary encoder and the secondary encoder, wherein the spare battery does not supply current to the detection unit of the primary encoder.

6. The actuator according to claim 5, wherein the auxiliary battery is charged when current is supplied from an external source to the primary encoder and the secondary encoder.

7. The actuator according to claim 5 or 6, wherein when no external current is supplied to the primary encoder and the secondary encoder, and the secondary encoder is supplied with current by the backup battery, the secondary encoder performs detection intermittently at a lower frequency than when an external current is supplied to the secondary encoder.

8. The actuator according to claim 7, wherein the intermittent period during the intermittent detection is set to decrease as the rotational speed of the output shaft increases.

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