Papers by Author: Xian Guo Han

Abstract: Analysis on the singularity of the 3-RPS parallel machine which probably occurs in the engineering application is presented. The influence of the singular configurations in the workspace of the parallel machine is interpreted. To improve the orientation capacity of the moving platform, a novel complex spherical joint is designed, however a special singularity namely coaxial singularity is resulted in. By optimizing the dimension parameters and designing a special moving platform, the singularity can be averted in the wanted workspace, and the nutation angle of the parallel machine can be enlarged to ±45 degree.

Abstract: The paper presents a new multi-dimensional loading structure based on parallel mechanism used for testing the materials and components. The mechanics of structure is introduced, kinematics and control model is analyzed, and loadings are simulated. It shows that because various actual forces can be supplied and controlled, static and dynamic performances of components can be evaluated by this structure, with which the capacity of the load-bearing can be ensured accurately. The data obtained by this structure is very important for the design of the materials and the components.

Abstract: According to the inverse solutions of 3-RPS parallel machine tools, the mapping relationship between the geometrical errors built on the 3-RPS parallel machine tools and errors of out posture has been created, then the error model of direct solutions including all the geometrical parameter errors has been built, and this model can be directly used to analyse the accuracy of parallel mechanism. On this basis, the algorithm about error compensation has been proposed. Moreover, accuracy synthesis of 3-RPS parallel machine tools was made respectively in probabilistic synthesis method and extreme synthesis method, and at last these two methods were compared.

Abstract: Based on the screw theory, the force analysis of the 3-RPS parallel machine is illuminated. Been equivalent to a 6-chain parallel machine, the deformation harmony equation of the parallel machine under the outside generalized force is interpreted. The instantaneous stiffness model of the parallel machine, which includes the change of the force Jacobian matrix, is established. Considering the deviation of the position and orientation of the moving platform, which is resulted from the distortion of the PRS chains of the parallel machine, the influence of the change of the Jacobian matrix to the instantaneous stiffness model of the 3-RPS parallel machine is analyzed, and furthermore, it is verified with an instance.

Abstract: The development of a virtual axis cutter grinder was introduced. The main contents of this paper include layout design, parameters design method, control system and program system. The purpose of the development of the parallel machine tools is for cutter grinding. The dimension of the cutter and the translation workspace for cutter grinding usually is small and is therefore suitable for the parallel machine tool application. The new machine tool has high rigidity and good precision.