Dynamics Study Of Rssr Mechanism Considering Flexible Rods And Spherical Clearance Joint

In robotics,aerospace,medical and other fields,with the development of science and technology,the increasingly high requirements of mechanical system design,its functions that can process more complex tasks are more powerful,and issues when designing and manufacturing need to be considered more deeply.Therefore,the dynamics study of the RSSR spatial mechanism in this paper is significant.Few researchers research the spatial mechanism with clearance because of its advancing,and less researchers research the spatial compliant mechanism with clearance because it is more advanced.Therefore,the research has very high practical value although it has certain theoretical difficulty.In recent years,there have been some achievements in the research of spatial mechanisms with clearance joints,but there are still many problems to be solved urgently.In order to analyze the dynamics of the spatial mechanism better,and compensate the output error,and extend the service life of the equipment,and meet the performance requirements,this paper research the dynamics of the spatial mechanism from several aspects.The elastodynamics of the RSSR spatial mechanisms was analyzed.Without considering the clearance of the spherical joint,the rods in the mechanism is considered as a flexible component in elastic deformation problem.The elastic error is expressed with the generalized coordinates of each element by the finite element analysis method,and the elastodynamics model of the RSSR spatial mechanism is established by using the second Lagrange method and the kinematic constraint conditions.Through dynamic equation solving and simulation analysis,the variation law of elastic vibration displacement of the system as time goes by.The clearance dynamics of the RSSR spatial mechanisms was analyzed.Ignoring the elasticity of each rod,and because of the complexity of the Spherical joint,we only consider the clearance of the Spherical joint near the output side.After the appropriate clearance impact mechanics model is selected,the dynamic model of the RSSR spatial mechanism with clearance joint is established by using the first Lagrange method.Through dynamic equation solving and simulation analysis,we can obtain the variation law of the displacement error of each component as time goes by.The elastic clearance dynamic of the RSSR spatial mechanism with elastic and clearance coexisting was analyzed.The rod elasticity is introduced on the basis of the clearance dynamics.Because of the connecting rod flexibility,the actual joint clearance of the mechanism is changed during the operation.Therefore,an idea of virtual gap is put forward,and the displacement error caused by the flexible link is added to the gap of the spherical joint to analyze the clearance dynamics,and the variation rules of the variables of the system with time are obtained.In this paper,an idea of virtual clearance is put forward.That is,the displacement error caused by the flexible rod is added to the clearance of the spherical joint to analyze the clearance dynamics,and the variation law of each variable as time goes by.Through the above work,we can make regular compensation for the input of the mechanism,so that the mechanism can keep the accuracy for a long time,be stable operation,and increase the service life.