External sensory feedback control for end-effector of flexible multi-link manipulators

A method is proposed to control the tip of a flexible multilink manipulator. The external sensory feedback controller can be easily constructed in task-oriented coordinates (for example Cartesian coordinates) without complex calculation for inverse kinematics or inverse dynamics. To realize the control method, a reduced-order approximate Jacobian which is formed by the motion of both rigid and flexible modes of the manipulator is introduced. The effectiveness of the proposed control method based on the approximate Jacobian is proved by using L₂ stability theory. The practical usefulness of the method is demonstrated by some experimental results for a flexible two-link manipulator