Kinematic Analysis Of 3-RPRR Parallel Mechanism

Less DOF mechanism as an important part of the parallel mechanism, has the advantages of simple structure and low cost. However, which has become a hot issue in mechanisms that increase the study of less freedom model. Professor Li Qinchuan combines the various possible models by using spiral theory. On this basis, the article raised a new type, the structure symmetry of 3-RPRR less freedom parallel mechanism and utilized the method of Combined with theoretical calculation and software simulation for kinematics analysis of the mechanism. The research of this paper can enrich the DOF models and lay the foundation of theoretical research and practical application for three mobile parallel mechanism. The specific research contents are as follows :1) Firstly, established the coordinate system of the mechanism and described its structure, writed down the spiral movement of each joint. Using the correlation constraint screw, analysised the over-constrained of moving platforms and accessed to the motion nature of the mechanism. Through the K-G formula of correction, calculated the degree of freedom of the mechanism and Verified the correctness for the spiral theoretical analysis. By adopting the principle of fixing the input motion screw, judged the rationality for selecting the original driving link.2) Secondly, D-H method were used to establish the kinematic equations according to the motion character of the mechanism. The positive and negative solutions of the mechanism were obtained by using the continuous technique and were verified numerically. The visualization of positive solution configuration was realized through Using the matlab software to write a drawing program. The jacobian matrix is established by making use of the kinematic equations of the mechanism. The singular configuretion was obtained in the light for the principle determinant of the jacobian matrix is zero.3) Finally, the solid model of the mechanism was build by using PRO/E software and was import into ADAMS software for having a kinematics simulation. the rightness of motion pair connection and freedom calculation results were test by viewing solid model information of ADAMS software. The simulation parameter was given and the location map of the mechanism was got. According to the simulation results, fetched curve parameters of position change for having relative motion components. After analyzing these curves, the correctness of theoretical research is confirm by combining theory analysis and simulation result.