Calibration of three dimensional mechanism-novel calibration method for 3 DOF parallel mechanism

Many types of three dimensional mechanisms (3D-mechanism) are used in modern industry. Specially, in automation technology, product engineering and robotics, 3D-mechanisms play the key roles of complicated manipulation, 3D positioning and 3D measurement. Usually, the repeatability of 3D-mechanism is tested and evaluated. However, when we use 3D-mechanisms for wide purposes and over wide conditions, the absolute calibration is the key technique to control the mechanism precisely. We analyze theoretically the method of absolute calibration for 3D-mechanisms, such as a Cartesian mechanism, an articulated mechanism and a parallel mechanism. After theoretical analysis, we introduce a 3 DOF parallel mechanism for a coordinate measuring machine (CMM) and a micro milling machine and a calibration method for these parallel mechanisms.