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 the singular perturbation theory, a slow subsystem associated with rigid motion dynamics and a fast sub-system associated with link flexible dynamics are identified. Hence, a two-time scale control strategy is adopted, consisting of a force and position control action for the slow sub-system 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.