| Radar antenna(or satellite antenna)is the high precision equipment,and it has a high requirement for pointing accuracy and motion stability.The parallel mechanism has the advantages of large bearing capacity and small accumulated error.Therefore,the application of the parallel mechanism to the radar antenna can improve the accuracy and stability of the antenna.In practical application,it is inevitable that the clearance of the kinematic pair in the mechanism.In this case,the influence of the kinematic pair clearance on the accuracy of the antenna can't be ignored.The existence of the clearance pair will also aggravate the joint wear,and the wear is one of the most important reasons for the failure of equipment.In view of this,the 3RSR(R denotes the revolute pair and S denotes the spherical pair)parallel antenna pedestal was taken as the research object,in this paper,considering the clearance of the spherical pair,to establish the dynamic model,to study the error and dynamic characteristics,and analyze the wear characteristics of the clearance spherical pair.The paper main research content is as follows:Drawing three-dimensional structure model of the 3RSR parallel antenna pedestal,establishing the dynamic model of the ideal 3RSR parallel mechanism;to build the normal impact force model and tangential friction model,embed the impact force and friction model into the Multi-body dynamics equation and to derive the dynamic model of the 3RSR parallel mechanism with clearance.Based on the ADAMS software,the dynamic model of the ideal 3RSR mechanism was established,the dynamic model of the 3RSR mechanism with spherical pair clearance was solved by Matlab software and the simulation results were compared.Changing simulation parameters,the dynamic response of the 3RSR parallel antenna pedestal with different clearances,different driving frequencies and different load conditions were solved,and the influence of different parameters on the dynamic performance of the mechanism is analyzed.Furthermore,the dynamic model of multi spherical joint clearance is established,and the corresponding simulation analysis is carried out.Based on the Archard wear model,establish the wear model of the spherical pair clearance,embed it into the dynamic model of 3RSR parallel mechanism with clearance,and solve the amount of wear by Matlab software.Then feedback the wear quantity into the dynamic equation,and the dynamic characteristics of the wear are analyzed.Based on the 3RSR parallel antenna pedestal mechanism,considering the bearing capacity and working space of the antenna,the new configuration of the improved parallel antenna pedestal are proposed. |
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