Vibration reduction of flexible manipulators using torque wheels

Abstract

This paper presents a vibration reducing technique concerning motion-induced vibration of a flexible manipulator. The proposed method uses a wheel-like rigid body as a torque generator. When this torque wheel drives along a specified path, the reduction of vibration occurs as the torque cancels the motion-induced force. In this study, the manipulator moves along its prescribed rigid-body motions. Even if the manipulator has nonlinear coupling terms, these can be changed to linear time varying terms. To reduce the order of motion induced force, an instantaneous modal coordinate is introduced to the linear time varying system. A wheel driving torque at specific time t* can be calculated in the modal space. The torque profile is synthesized with discrete torque values. This technique was tested both numerically and experimentally. In the experimental part, the control system to reduce the vibration was designed by combining the prescribed joint motions and the feedforward compensation of the torque wheel.