Tightening torque estimation of a screw tightening robot

Abstract

A screw tightening robot with AC servomotors, without any torque sensor was developed for a variety of screws. In order to detect the accurate tightening torque, we developed a new torque estimation method by measuring the electrical current of the motor and calculating it in real time. The screw-driving process is controlled by the 4th joint's motion of the robot. Thus, this robot can tighten screws accurately and reliably without extra cost.