A hybrid actuator scheme for robust position control of a flexible single-link manipulator

This article presents a novel hybrid actuator scheme to actively and robustly control the endpoint position of a very flexible single-link manipulator. The control scheme consists of two actuators; a motor mounted at the beam hub and a piezoceramic bonded to the surface of the flexible link. The control torque of the motor, which produces a desired angular motion, is determined by employing the sliding mode control theory on the equation of motion of the rigid link having the same mass as that of the proposed flexible link. The torque is then applied to the flexible manipulator to activate the commanded motion. During the motion, the undesirable oscillation caused by the torque, based on the rigid link dynamics, is actively suppressed by applying a feedback control voltage to the piezoceramic actuator. Consequently, desired tip motion is achieved. Both regulating and tracking control responses are analyzed through experimental implementation to demonstrate high performance characteristics to be accrued from the proposed methodology.