맥스웰-슬립 모델을 이용한 토크제어 로봇의 직접 교시 성능 개선

Direct teaching is a technique in which the operator holds the robot's end-effector and moves it to the desired position to teach the task. Direct teaching is available in a torque-controlled robot using the robot's dynamics and friction model without a force/torque sensor or joint torque sensors. In this case, the direct teaching performance depends on the accuracy of the model, and in general, the modeling error occurs mostly in the friction model. In this study, a friction model based on the Maxwell-slip model was introduced to eliminate the discontinuity of static friction compensation occurring in the Coulomb-viscous friction model. Continuous friction compensation based on the Maxwell-slip friction model reduces the amount of force the user should apply to the robot for direct teaching. It is also suitable for users to create smooth position and velocity trajectories because no sudden changes occur.