Control of industrial robots with flexible joints

Flexibilities in the manipulator structure limits its ability to perform high precision manipulation. In this paper, the effects of joint flexibility on the positioning performance of the end effector are considered. A "realistic" lumped-parameter dynamic model of the servo-mechanism is presented in order to develop a control structure to regulate the apparent torsional stiffness of the joint. The joint compliance can be compensated by using adequate feed-forward control. Computer simulation results are provided to illustrate this formulation.