Force-feedback control of parallel manipulators

The main features of a parallel manipulator are summarized, and it is shown that their passive compliance can be completely controlled. This feature is particularly important for improving the efficiency of force-feedback control methods and the stability. A prototype parallel manipulator is designed which includes force sensing. A novel force-feedback method is implemented and assembly experiments are performed with parts of various shape and rigidity and with very tight clearance (less than 10 μ). One purpose of these experiments was to determine the importance of the passive compliance of the manipulator. It is shown clearly that the force-feedback method greatly improves the insertion process