The Kinematics Analysis Of 3-RPS Parallel Machine Tool

With the development of CNC machine tools, parallel machine tool as a new tool has been used in many important areas. In view the needs of practical application, lower-mobility parallel mechanism became study hot spot. While the 3-RPS parallel machine tool own high structural stiffness, fast response speed, three parallel drives, which will help real-time control, its study is representational in lower-mobility parallel mechanism. Kinematic analysis is an important part of mechanism analysis, and is important foundation of mechanism dynamics analysis, control analysis, error analysis and other aspects. This paper will systematically analyze the kinematic of 3-RPS parallel machine tool, developed by institute of advanced manufacturing and its automation, provide early kinematic performance evaluation and basis of for control analysis.Firstly, the paper establishes a 3-RPS parallel machine tool’s kinematics model to analyze the degree of freedom and the independence posture parameters of the mechanism. The paper uses two methods to solve inverse kinematics and verify the correctness of two analysis methods. Based on the inverse kinematics model the paper searches for the workspace by the MATLAB program and get the scope application of the machine.Secondly, the paper analyzes the method of the Jacobian matrix and points out the existing method of Jacobian matrix analysis limitations for 3-RPS parallel mechanism. On the basis of forefathers, the paper improves the constructed vector of Jacobian, which can evaluate dexterity and singularity scientifically.Thirdly, with the help of developed Jacobian matrix the paper analyses the dexterity and singularity for the characteristics of the workspace, and analyses the kinematic performance of mechanism with the workspace features and flexibility index for providing more scientific evaluation of the mechanism’s performance to the basis of motion.Finally, the paper introduces SimMechanics toolbox systematically. Simulate the three-dimensional entity of the 3-RPS parallel machine tool, real-time observes the response speed of mechanism and verifies the analyticalcorrectness of the workspace and dexterity for providing the basis to following locus planning and structural optimization.