Trajectory tracking of flexible joint manipulators actuated by DC-motors under random disturbances

Abstract For a class of flexible joint manipulators actuated by DC-motors, the problem of modeling and trajectory tracking control under random disturbances is considered in this paper. How to describe random disturbances and introduce them to the system is the key for modeling and control. According to the relative motion and the equivalent circuit, the effect of random disturbances can be regarded as torque or voltage disturbed by colored noises. Thus, a random model is constructed. By using the vectorial backstepping and the technique of separating out the noise from coupled terms, a state feedback tracking controller is designed such that the state of closed-loop system has an asymptotic gain in the 2nd moment and the mean square of tracking error converges to an arbitrarily small neighborhood of zero by tuning design parameters. The effectiveness of the proposed scheme is demonstrated by the simulation results for a two-link robot.