Novel Joint Angle Measurement and Calibration System for Selective Compliance Assembly Robot Arm

摘要

In this study, a laser measurement device was designed to measure the axial angle errors of a selective compliance assembly robot arm (SCARA) joint. The proposed measurement system includes an optical measurement device that is installed on a high-precision index table and a reflective mirror that is installed on the end effector of the SCARA. The optical measurement device consists of a one-dimensional position-sensing detector, a polarized beam splitter (PBS), a laser diode (LD), a 1/4-wave plate (lambda/4WP), a collimating lens (C), and a reflective mirror. The device is easy to operate, inexpensive, and highly accurate. The axial angle error of the SCARA joint can be measured using the measurement device and a high-precision index table after calibration. The experimental results show that the positioning accuracy of the J1 axis improved from 25.6 to 8.1 arcsec, and that of the J2 axis improved from 7.3 to 2.3 arcsec after the angular positioning error was compensated.