Determination of Joint Velocities of Robots by Using Screws

Abstract

The screw theory is applied to determination of joint velocities of robot arms. The method described in this paper can be directly used for the straight line trajectory control of existing industrial robots. Joint velocities are computed by taking inner products of two kinds of screws, one of which is an element of an orthogonal basis of the screw system composed of joint screws and another is the screw representing an instantaneous motion of an end effector. The computation can be performed during a sampling period while a robot is in motion.