Utilization of torque wheels for active damping of flexible manipulators

Utilization of inertial actuators, such as torque wheels, for vibration damping of a single-link flexible manipulator is considered. The torque wheel is mounted at the end effector of the manipulator to provide a bending moment at the tip for vibration suppression and pointing purposes. The torque exerted by the torque wheel at the end-effector of the manipulator is achieved through controlling the velocity of the torque wheel. A decentralized control scheme is advocated in this paper for slewing and vibration suppression. The local loop around the torque wheel is closed through feedback of the accelerometer signal at the tip. Experimental results are provided to show the effectiveness of the proposed method for end-effector positioning of flexible-link manipulators. Although the experimental results reported are for a single-link flexible manipulator, the results are applicable to the multi-link case. It may be shown that the dynamics from the voltage input to the torque wheel mounted at the tip to the tip position is minimum phase and hence invertible given that an inner-loop controller has been applied to stabilize the rigid-body motion