| In this paper, based on the analysis of the research status of the driving simulator, regarding the shortcomings of the traditional Stewart platform which can’t rotate around the Z-axis within360°range, for this reason, the feeling of the driving simulator simulating vehicle turning continuously was limited. The6-RSPS platform which can rotate360°around the Z-axis was proposed. Some key technologies such as the kinematics, dynamics, accuracy analysis, workspace and washout algorithm of6-RSPS were studied systematically. The effective and feasibility of the theory proposed was verified by simulation. Specific research contents are as follows:6-RSPS platform for simulator was proposed, the design scheme of the mechanism was determined, and the degree of freedom of the mechanism was calculated. According to the vector relationship of the link-length, the relationship between the position and orientation of the platform and the length of the telescopic link and rotation angle of link was obtained, then, a group of inverse solution was deduced. Compare to the classic Stewart platform which has only one inverse solution, the6-RSPS platform has more than one inverse solution. So the conditions of the constraints and optimization of the relevant parameters was proposed, and the optimal inverse solution of the mechanism was obtained according to the conditions. In order to get the forward kinematics of the6-RSPS parallel mechanism, BFS algorithm was proposed and great results was achieved.The factors that influence the accuracy of the6-RSPS platform were analyzed, the overall error model was established in accordance with the principle of independent role of the error, the independent error model of all factors was established by using the differential method for kinematic equations. The impact on the accuracy of the moving platform generated by the error of rotate-angle, the error of link-length, the error of joint on static platform and the error of joint on moving platform and so forth were discussed, and verified the correctness by simulation. Based on this model, the accuracy of position and orientation of6-RSPS platform can be assessed, providing a theoretical basis for improving the accuracy of position and orientation further.Statics of the6-RSPS mechanism was analysis by the principle of virtual work, and the model of statics was established. The driving force of stretching-link and driving torque of rotating-link under different position and orientation was obtained. Inverse dynamics of the6-RSPS mechanism was analyzed by Kane principle, and the model of inverse dynamics was established. The driving force of stretching-link and driving torque of rotating-link under moving was obtained. The correctness of the modeling was verified according to simulation, providing a theoretical basis for dynamic optimization, control and simulation.The factors that influence the workspace of the6-RSPS platform were analyzed, and how these factors restrict the position and orientation of the platform was studied. Regarding the characteristics of the mechanism, proposing the method of search the workspace on the surface of YOZ on the positive of Y-axis cross-section, and then rotate360°, the3-D workspace was obtained. The efficiency of searching process was improved, and several workspaces under multiple position and orientation state were obtained using this method.Based on the classical washout algorithm on the Stewart platform, regarding the characteristics of6-RSPS, a new washout algorithm suitable for the mechanism was proposed, and related parameters of the algorithm were researched. The results of simulation experiment show:the washout algorithm that without washouting the rotation on the direction of the Z-axis for6-RSPS platform is feasible and appropriate. It proved that it can be able to simulate the feeling of simulator simulating vehicle turning continuously more accurately and effectively. |
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