Accuracy Study Of 3-DOF Translational Parallel Robot Mechanisms

Accuracy is one of the most important working performances of parallel robotmechanism, which affect the working accuracy of the parallel robot directly. Thisdissertation deals systematically with the error analysis and accuracy compensation of3-DOF parallel translational manipulators, based on the study of kinematics and workspaceof it.Topological structure of 3-DOF parallel translational mechanism is analyzed, and theclosed-formed analytic solutions for both the forward and inverse kinematics aredeveloped by using vector method. The closed-formed analytic solutions of parallelmechanism' workspace is obtained, which offered maximum facilities for the further studyof parallel mechanism.According to the inverse solutions of 3-DOF translational parallel robot mechanisms,in which both the base and the mobile platform are triangle and similar to each other, theaccurate model of parallel robot mechanisms is established by the differentiation of thekinematics. The effects of length error of driving poles, structure size change and posturechange on the accuracy of robot are studied by simulations, which provided a foundationfor practical error compensation and control of the mechanism.A method of accuracy compensation of 3-DOF translational parallel robotmechanisms is proposed theoretically by using the forward error model of translationalparallel mechanisms, for the 3-DOF translational parallel robot mechanisms have threetranslational freedoms. The purpose of improving the output position and pose accuracy ofparallel mechanisms is realized, with controlling telescopic link of parallel mechanisms. Atlast the method is proved effective by example simulation.