Torque detecting method and arm device

摘要

According to a torque detecting method, gravitational torque applied to a rotary shaft of an arm is detected in a condition where position control of the arm is stopped, when the arm is located at a first position at which the arm is oriented in a direction different from a direction of gravitational force. Then, a gravity coefficient used for calculating gravitational torque corresponding to a position of the arm is calculated, based on the gravitational torque and the first position. Then, gravitational torque during position control is calculated, based on the position of the arm detected during the position control, and the gravity coefficient. Further, an actual output torque during the position control is calculated, based on operating torque applied to the rotary shaft and detected during the position control, and the gravitational torque calculated during the position control.

主权项

1. An arm device, comprising:
an arm operable to rotate integrally with a rotary shaft; a driving device that drives and rotates the arm; a torque detector that detects torque applied to the rotary shaft of the arm; a position detector that detects a position of the arm; and a controller that outputs a control signal to the driving device so as to perform position control on the arm, wherein: the torque detector detects gravitational torque applied to the rotary shaft in a condition in which the controller stops the position control of the arm, when the arm is located at a first position at which the arm is oriented in a direction that is different from a direction of gravitational force; the controller calculates a gravity coefficient used for calculating gravitational torque corresponding to a position of the arm, based on the gravitational torque and the first position; the controller calculates the gravitational torque during the position control, based on the position of the arm detected by the position detector during the position control of the arm, and the gravity coefficient; the controller calculates actual output torque applied to the rotary shaft during the position control, based on operating torque applied to the rotary shaft and detected by the torque detector during the position control, and the gravitational torque calculated during the position control; and the controller outputs the control signal to the driving device, based on the actual output torque, so as to rotate the arm.