Calibration of Stewart platform based on coordinate measurement

Aiming at the kinematics accuracy problem of the Stewart platform in the space docking hybrid simulation system, a cost effective calibration technique based on coordinate measurement is presented. The main idea is to acquire the position and orientation information of the platform by the coordinate measuring machine and construct a residual equation with uniform units. Then the platform´s geometry parameters can be identified to compensate for its kinematics errors. The advantages of this method are that each geometry parameter´s identifiability is ensured; no special auxiliary calibration equipments or redundant sensors are required to be designed and manufactured high adaptability and good operating characteristic are available. After the calibration procedure is described and the strategy on constructing the residual equation is discussed, a simulation shows that the kinematics accuracy after calibration can reach the same order of magnitude as measurement noises. Applying this method to an actual Stewart platform, the accuracy improves more than 5 times after compensation.