Redundant actuators to achieve minimal vibration trajectory tracking of flexible multibodies: Theory and application

We address the problem of inverse dynamics for flexible multibodies, which arises, in trajectory tracking control of flexible multibodies such as space manipulators and articulated flexible structures. Previous research has resolved this trajectory tracking problem by computing the system inputs for feedforward control of actuators at the joints. Recently, the use of distributed actuators like electro-strictive actuators in flexible structures has introduced a new dimension to this trajectory tracking problem. In this paper we optimally utilize such actuators to aid joint actuators for tracking control, and introduce a new inverse dynamics scheme for simultaneously (1) tracking a prescribed trajectory and (2) minimizing ensuing elastic deflections. We apply this scheme for trajectory tracking of a two-link two-joint planar manipulator with joint motors and distributed electro-strictive actuators. Experimental results are presented to contrast our new scheme with other existing methods.