Flexible robot arm control by a feedback linearization/singular perturbation approach

A nonlinear tracking controller for the link-tip positions and velocities of a multi-link flexible robot arm that gives guaranteed performance is designed. The controller has three loops: an outer tracking loop, an inner loop based on input-output feedback linearization, and an additional inner loop that stabilizes the internal dynamics, e.g., the flexible modes, using a singular perturbation design. It is found that the flexible mode trajectories have two parts. One part depends algebraically on the desired tip positions. A boundary layer correction part can be used to stabilize the flexible motion