Parallel force and position control of flexible manipulators

The problem of controlling the interaction of a flexible link manipulator with a compliant environment is considered. The manipulator's tip is required to keep contact with a surface by applying a constant force and maintaining a prescribed position or following a desired path on the surface. Using singular perturbation theory, the system is decomposed into a slow subsystem associated with rigid motion and a fast subsystem associated with link flexible dynamics. A parallel force and position control developed for rigid robots is adopted for the slow subsystem while a fast control action is employed to stabilise the link deflections. Simulation results are presented for a two-link planar manipulator under gravity in contact with an elastically compliant surface.