Kinematically redundant robots with flexible components - IEEE Control Systems Magazine

of joint elasticity and kinematic redundancy. More specifically, manipulators in which there are more controlled (joint space) degrees of freedom than task space degrees of freedom and in which at least one of these controlled joints is connected to an adjacent link through an elastic coupling are discussed. It will be shown that there is a wide class of examples for which it is impossible to find joint space motions which track a given end effector trajectory and do not at the same time excite elastic dynamics. No assumptions on the smoothness of the prescribed end effector trajectory or the degree of redundancy alter this conclusion. For this class of robot manipulator geometries, the most we can in general hope to do is to plan motions which move the end effector between prescribed endpoints without any net storage of elastic energy in the joints. For certain congenial manipulator geometries (including cases in which all joints are revolute). it is shown that under certain assumptions it is possible to plan motions which store no elastic energy. These motions