A new control scheme of single-link flexible manipulators robust to payload changes

A new scheme is presented in this paper to control single-link flexible manipulators. The objective is to control the tip position of the flexible arm in the presence of joint friction and payload changes. The control scheme is based on two nested loops: an inner feedback loop to control the motor position which is robust to joint friction, and an outer loop to control the tip position which is robust to payload changes. This outer loop is composed of a feedforward term and a feedback term. This results in a simple control law that needs minimal computing effort and, thus, can be used for real time control of flexible arms. The proposed method is general in the sense that it can be applied to very different arm structures and diverse sensor systems configurations. Results corresponding to two different arm setups are presented.