Two-time scale force and position control of flexible manipulators

The problem of controlling force and position of a flexible link manipulator in contact with a compliant environment is considered in this paper. Using singular perturbation theory, a slow subsystem associated with rigid motion dynamics and a fast subsystem associated with link flexible dynamics are identified. Hence a two-time scale control strategy is adopted, consisting in a force and position control action for the slow subsystem and a stabilizing action for the fast subsystem. Both regulation and tracking problems are considered for the position, while the contact force is kept to a constant desired value. Simulations are presented for a two-link planar manipulator under gravity.