| Flexible parallel mechanisms combines the characteristics of flexible mechanisms and parallel mechanisms,have the advantages of light weight,operation with high speed,high load weight ratio,low power consumption and compact structure,etc.They have a bright future and important practical value and theoretical significance,now,this subject has become a frontier topic in the field of mechanism research and application.In this paper,taking the tripod parallel CNC machine in Northeastern University laboratory as the object,then we research the dynamic aspect of it,including dynamic modeling of the machine tool,dynamic analysis,dynamic simulation,dynamic characteristic analysis and optimal design,etc.The research work of this paper is as follows:(1)Study and establish the dynamic model of flexible tripod parallel universal joint,and solve it.Establish a flexible space element model,derive the dynamic equations of the flexible beam element and the branch of this parallel mechanism.The dynamic equations of each branch chain,motion and dynamic constraints are assembled to get the system dynamic equation.Then the equation of this machine tool can be solved by MATLAB.(2)dynamic analysis of flexible parallel machine tool.Analyze the motive power and the dynamic stress of this flexible machine tool,according to the element dynamics model of the system component,carry out the dynamic analysis of components;The formula for solving the dynamic stress of the flexible element is given,the maximum value of the dynamic stress of a system component on any section is obtained.(3)dynamic simulation of this flexible parallel machine tool.Use Solid Works to establish 3D model of the parallel machine tool,then it is imported into ANSYS and Adams,after that,the dynamic simulation is conducted.Compare the results of simulation software with the results of numerical simulation.(4)Analyze the dynamic characteristic this flexible parallel machine tool.Study the relationship between the natural frequency of the system and the basic parameters of the mechanism,and carry out the optimization design of this flexible parallel machine tool.Taking the fundamental frequency and driving force as the optimization objective,we optimize the basic parameters of machine tool components,improve the kinematic accuracy of this flexible parallel machine tool,reduce the wear and tear of the components,and save energy consumption.Finally,carry out the experiment research.Analyze the error of actual experimental results and theoretical results,illustrate the effect of elastic deformation of flexible bars on the machine tool by experiment. |
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