Self-calibration of parallel manipulators using an orientation constraint

A self-calibration method for parallel manipulators is presented with its main idea of keeping two attitude angles of the end-effector constant. The orientation constraint is realized physically by levelling a commercial biaxial inclinometer installed on the end-effector through an active adjusting mode. The used measurement configurations are optimized to reduce the influence of sensor noise on calibration, and the effectiveness of the proposed method is verified by simulation results.