Self-Calibration of Redundantly Actuated PKM Exploiting Kinematic Landmarks

A self-calibration method for redundantly actuated parallel manipulators (RA-PKM) is proposed that uses motion reversal points (MRP) of actuators as kinematic calibration landmarks. The basic principle is to restrain a RA-PKM to 1 DOF and detect the MRP of redundant actuators. The difference of measured MRP and those deduced from a kinematic model embodies the calibration error. Therewith a numerical adaptation scheme is introduced. Simulation results for a 3 DOF RA-PKM confirm very high accuracy of the method.