Force-free control of articulated robot arm considering velocity along assigned locus

Force-free control with velocity consideration under the assigned locus is proposed for an articulated robot arm. The tip of the robot arm is moved on an objective locus according to the tip velocity. Then, the direction of the tip velocity, which corresponds to the exerted force, is modified to the tangential direction of the assigned locus. The contouring work of an articulated robot arm is, therefore, carried out with a force-free control. The effectiveness of the proposed force-free control is assured by simulation and experimental work on a two-degree-of-freedom articulated robot arm. Applications of the force-free control with an assigned locus are also discussed.