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An error-model study of a new type of coordinate-measuring machine based on the parallel-link mechanism

Firstly, this paper establishes the inverse kinematic model of a new coordinate measuring machine (CMM) based on the parallel-link mechanism with three spatial degrees of freedom (3DOFs). Then, based on the differentiation of the kinematics, the relation between the input parameter errors, which consist of the position errors of the joints and the kinematic errors of the actuators, and the output errors at the probe of the new CMM, is derived; thereby the error model is presented. Finally, the error model is verified by computer simulation, and the result indicates that the error model established in this paper can approximately report the changing trend of the actual measuring errors where the input errors are small enough. This research provides an essential theoretical basis for calibrating the new parallel-link CMM.