Control of robots with flexible joints

Abstract

The motion of a robot with flexible joints is considered in the case of dynamic control. The robot consists of n rigid links connected together and is driven by n independent actuators. We use a semi-analytical approach based on the method of averaging which allows one to separate the dynamics of the robot as a whole from its elastic vibrations. This approach was applied earlier by Chernousko (1981) and Chernousko et al. (1994) for analysis of motions of robots under the assumption that the stiffness of the joints is high. In this paper we also assume that the gear ratios of the actuators are sufficiently high. By means of the mentioned technique, a constructive procedure is obtained for dynamics simulation. As a result, the integration of the nonlinear equations of motion can be replaced by the integration of a simpler system of differential equations with large step.