| After a summary on the study of PKM (Parallel Kinematics Machine Tool) both at home and abroad, the machining performance of the PKM named BJ-04-02(A) is studied in the paper. First, the problems such as the inverse kinematics solution of the position, machine error and error model are discussed based on the fundamental theory of the PKM. Then, the simulation analysis is carried out on the workspace of the PKM. Finally, the machining performance of the PKM is experimentally evaluated. The main work and the results obtained are as follows:1. The basic error classification and the source of structural error of the PKM are introduced. It is pointed out that the key of precision analysis of the PKM is to establish the pose error model of a cutting tool. The error model of the PKM named BJ-04-02(A) is obtained by the differential vector method. And the model, the relationship between structural parameters and error of the mobile platform is discussed.2. The workspace of PKM is analyzed, and the solid simulated model of the workspace of the PKM named BJ-04-02(A) is described. By considering structural constrains, workspace boundary points of the PKM are obtained by a coordinates searching method, and the workspace boundary surfaces are produced. The simulation results are consistent well with the actual ones, and this shows that the model is correct.3. The machining accuracy and the surface finish of the PKM named BJ-04-02(A) are evaluated by machining two standard workpiece. The machining accuracy includes that of size, shape and position, Size includes the diameter and length. Shape includes straight, circular and cylinder, Position includes perpendicular, parall, slope and concentrate. The experiment results show that the surface finish and the straightness are basically filled with JB/T8771.7-1998, but the other accuracy indexes are not consistent well with the mechanical standards. And the machining accuracy will become bad with the tool far away from the center of the workspace.
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