Design And Analysis Of A 2(2-UPR+RPU) Serial-parallel Hybrid Mechanism

With the structural transformation and reform of social production,the automation of various industrial machinery has improved,and the proportion of automated machinery in production has been increasing.In this study,based on the engraving industry,based on the engraving technology,a new 2(2-UPR+RPU)serial-parallel hybrid machine tool mechanism was designed.The mechanism adopts a modular design idea,which can be based on the machine tool platform or three-dimensional mobile platform of the factory workshop,and achieve a good overlap through modular assembly.At the same time,it also combines the advantages of traditional series mechanisms and parallel mechanisms.This paper has carried out related research,analysis and simulation on the mechanism configuration,kinematics,statics and dynamics.The research shows that the new 2(2-UPR+RPU)series-parallel hybrid mechanism is compared with the existing The parallel mechanism and parallel-serial hybrid mechanism have greater processing workspace depth and execution end platform angle range,which meets the technical requirements of manual carving in the field of carving,thus laying a theoretical foundation for the subsequent trial production and commissioning of prototypes.This article mainly completed the following research contents:Firstly,a new type of 2(2-UPR+RPU)serial-parallel hybrid mechanism was constructed in accordance with the needs of the three-dimensional sculpture technology,and the number of degrees of freedom of the mechanism was analyzed using the spiral theory.Through the establishment of a three-dimensional solid model,draw a schematic diagram of the mechanism and a detailed configuration description and structural arrangement of the mechanism.The spiral theory is used to solve the quadratic anti-helix on the branch chain of the mechanism and the improved G-K formula is used to analyze the freedom of movement of the mechanism.At the same time,the movement form of the mechanism is analyzed,which meets the practical needs of three-dimensional sculpture carving.Secondly,the kinematic analysis of the 2(2-UPR+RPU)series parallel hybrid mechanism is carried out,including the inverse solution of position,the forward solution of velocity and acceleration.First,in the constructed coordinate system,Euler angles are used to represent the coordinate transformation relationship of key nodes of the mechanism.The analytical positional solution of the mechanism is analyzed by the analytical closed-loop vector method and the geometric method to obtain the calculation equation of the positional inverse solution of the mechanism.Secondly,the influence coefficient method is used to analyze the speed and acceleration of the mechanism,and the Jacobian matrix and Hessian matrix are derived,and the mapping relationship between the output and the input is obtained,which can provide a certain theoretical reference for the subsequent test machine control program compilation.Finally,the correctness of the theoretical model is verified by comparing the calculation and simulation results based on the software.Thirdly,the Jacobian algebra method is used to analyze the singularity of the mechanism,and the variable geometry method and the boundary numerical search idea are combined to solve the working space of the mechanism.First,according to the classification of the reasons for the formation of singular configuration,the Jacobian algebra method is used to analyze the singularity of the serial-parallel hybrid mechanism by judging whether the matrix is full rank,and provide suggestions for the subsequent improvement and improvement of the organization.The combination of variable geometry method and boundary numerical search idea is used to solve the working space to obtain the reachable working space of the mechanism.The results show that the new serial-parallel hybrid mechanism has a considerable working range and meets the design requirements required for the machining of the engraving machine tool mechanism.Forthly,The statics and stiffness of 2(2-UPR+RPU)series parallel hybrid mechanism are analyzed.The statics model of the mechanism is derived by the principle of virtual work.The stiffness matrix model of the series parallel hybrid mechanism is analyzed and established by Hooke's law.The static stiffness of the mechanism is analyzed in ANSYS Workbench,the maximum deformation of the mechanism in each limit position is obtained,the minimum stiffness is calculated,and the corresponding optimization and improvement suggestions are given through the analysis of the results.Finally,using the principle of virtual work,the 2(2-UPR+RPU)series-parallel hybrid mechanism was analyzed dynamically.Based on the principle of virtual work,the relationship between the driving force and torque of the branch chain and the execution end action platform is established using the Jacobian matrix and inertial matrix of the mechanism.Then,using the principle of virtual work,the relationship between the external load and the driving force and the stress of each component is constructed to establish the dynamic model of the serial-parallel hybrid mechanism.The numerical example is used to analyze the change of driving force.