Using Absolute Encoders for Motor Absolute position and Finding minimum Absolute Encoders Resolution

摘要

In a conventional power transmission device having a robot joint or a reducer, an incremental encoder (incremental type encoder) for measuring the rotation of a motor is attached to the motor, and in an output shaft of the reducer, a dual encoder system has been mostly used, in which an absolute encoder (absolute value encoder) for measuring the position of the output shaft of the reducer is attached to the output shaft. In this case, a resolution related to a position, at which the position of the output shaft is measured, can be increased by using signal values of two encoders. However, when a value corresponding to the position is read, the accuracy of the position as to how an accurate position is displayed cannot be increased. In order to solve the problem, the present invention provides a method for increasing both the position resolution and accuracy of the output shaft by using the absolute encoder (absolute value encoder or absolute position encoder) as the encoder attached to the motor shaft and also attaching the absolute encoder to the output shaft of the reducer. By the configuration, the position resolution of the output shaft can be increased to be higher than or equal to the resolution of the absolute encoder attached to the output shaft, thereby providing a means capable of precisely controlling medical equipment such as a surgical robot, artificial joints, and precision machines. In addition, provided is a method for selecting the minimum of the resolution of the absolute encoder attached to output shafts satisfying the above condition.