Kinematic Error Model for Trolley-type PUU

Because of the ability to move at high speed and the high stiffness, Parallel Kinematic Machines (PKMs) have been widely used in industry and research in recent years. In this paper, the kinematic error model was established for the trolley-type PUU (prismatic-universal-universal joint). Three translation errors were added to the ideal kinematic model present the joint position because of manufacturing and assembly. The calibration process included measuring the positioning error by a laser interferometer, identifying the error parameters using least square method and revised the kinematic model in the controller. After compensation, the positioning errors of end effector were indeed reduced. It could show the practicality of this model. Moreover, modifying the kinematics in the controller is a time-saving and convenient compensation method.