Abstract: In order to improve the accuracy of the parallel kinematics machine (PKM), a simple and effective calibration methods is proposed and testified, based on a real PKM with gantry structure. The observation matrix of calibration on relative position measurement is achieved from error model. The information of relative position is obtained using the universe instruments, and the calibration scheme is acquired through simulation according to the non-singularity of the observation matrix. The experiment has an excellent result. Because of the universality of the theory scheme and instruments, a universal calibration scheme is provided for the PKMs with a few degrees, to improve accuracy and accelerate their applications.

Key words: Calibration, Error compensation, Parallel kinematics machine