Dynamics Modeling And Simulation Of RSSR Spatial Mechanism With Spherical Clearance Joint

With the development of science and technology and social product ivity progress,precision instruments,aerospace industry,medical equipment,heavy equipment engineering and many other areas of mechanical equipment requires better performance.Machinery and equipment are moving towards high precision,high efficiency,high reliability and long life.Among them,the spatial mechanism in high-tech products,robots and other applications usually occupy a dominant position.In order to analysis the comprehensive performance of spatial mechanism in engineering,this paper will study the effects of spherical joint clearance on dynamic performance of spatial mechanism,based on RSSR spatial linkage mechanism as the main research object,modeling and simulation analysis of its dynamics,and provide a theoretical basis for the structure optimization design and error control of spatial mechanism with spherical clearance joint.The contents are as followings:First,the dynamic model of the ideal spatial mechanism of RSSR is established,and the output of the ideal spatial mechanism of RSSR is simulated accurately by comparing the results of the kinematic output.At the same time,the dynamic model of RSSR spatial mechanism with single spherical clearance joint is established;develop a computation algorithm with Matlab.The output characteristic of RSSR mechanism is obtained under the condition of clearance.Through the comparative analysis,the effect of selection of the contact impact force model,size of the joint clearance,driving speed,and selection of the joint material’s parameters on the dynamic output of the mechanism are explored.The simulation results show that the L-N model can better restore the output characteristics of mechanism with clearance;the clearance’s size influence the dynamic properties of the spatial mechanism most intensely,the larger the clearance size is,the more intensive of vibration is,but the clearance is not the smaller the better,while the clearance is small to a certain degree,the influence of the clearance’s size decreased rapidly;raising the input rotation speed will make the embedded depth deeper between the ball and the socket,adversely reduce the life of the spatial mechanism.The different materials between ball and socket will have a comprehensive impact on the contact impact,the larger contact stiffness is,the larger the impact force is,the shorter collision time is and the smaller embedded depth is.But the selection of the joint material’s parameters influence on acceleration of the output of the mechanism is still not clear.The dynamic simulation of spatial mechanism with clearance joint is summarized,and the frequent occurrence of the collision region is summarized,and shows the direction of structure optimization design.At the same time,the error of the output angle displacement is analyzed,the delay adjustment scheme is put forward,which greatly reduces the output error of the system.