| Parallel machine tools are also called virtual axis machine tools.Compared with the many disadvantages of traditional machine tools in processing,the emergence of parallel machine tools makes up for these shortcomings.In terms of structure,the structure of the parallel machine tool is changeable,it can adapt to various forms of processing,and it can also achieve some complicated processing.It also has a unique method when processing curved parts,and its executing parts are no longer simple motion accumulation.Therefore,large movement errors can be avoided,so that the machining accuracy is higher.In addition,the parallel structure machine tool has good dynamic performance and is easy to realize high-speed machining.This topic studies a new type of parallel-driven two-way mobile workbench.The base is equipped with a cross-shaped mobile component(composed of rolling guides and ball screws),and the X-direction and Y-direction mobile components have the same structure and movement mode.),The two ends of the fixed bracket plate on the moving component are respectively connected with mutually symmetrical groove brackets,and the movement of the upper table in two directions is realized through the connection of the groove brackets and the guide rail pair.Different from the traditional two-way moving table,this structure avoids the accumulation of errors in two directions of the table,and the four guide rails adopt the principle of over-positioning,thereby improving the machining accuracy and the rigidity of the table.This topic mainly studies the new parallel workbench through the following aspects(1)Based on the idea of a cross coupling,the concept of a parallel bidirectional mobile workbench is designed,and the modeling structure of the workbench is designed according to the design requirements.The workbench consists of ball screws,rolling guides,servo motors,etc.Calculate,select the most suitable model,and complete the three-dimensional structure of the main model of the workbench.Through the simulation of the motion of the model,it is proved that the model is theoretically achievable,and it can be further studied.(2)The Lagrange dynamic equation is an important method for studying the dynamics of parallel mechanisms.A speed equation is established for the workbench,and the speed Jacobian matrix of the workbench is obtained.The kinetic energy equation in the direction is used to further find the generalized force of the workbench.The obtained results are substituted into the Lagrange dynamic equation,and the equation is simplified.The Lagrange dynamic equation of the workbench is obtained.The specific numerical value is substituted into the equation to solve the theoretical value.The ADAMS software is used to perform dynamic simulation of the parallel bidirectional mobile workbench.The simulation results are compared with the theoretical calculation results.The difference between the two is small,and the correctness of the workbench dynamics is verified.(3)Analyze the platform based on the principle of error independence,classify the source errors of the components that make up the workbench,and solve the error limits of each component separately.Error limits in both directions.(4)Analyze the stiffness of the workbench,find the stiffness matrix of the workbench,use ANSYS Workbench to analyze the deformation of the workbench in the extreme position,and solve the deformation value of the workbench under a certain external force,and then solve Stiffness values,the results show that the table is feasible in the extreme position,without serious deformation. |
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