Analysis Of Deformation Characteristics And Synchronous Control Of Gantry Structure In NC Cutting Soft Slices Machine

With the development of China's aerospace industry,more and more research has been given for production equipment in related fields.In order to maintain China's lead in aerospace field and break the blockade of foreign technology,it is necessary to research and manufacture special processing equipment for some special components of aerospace equipment.The NC cutting soft slices machine studied in this paper is designed for processing thermal insulation soft slices in a space equipment.Because of the size and accuracy requirements of the processed soft slices,the tool holder needs a large-span moving space and high motion accuracy.Therefore,the gantry structure which is widely used in the design of machines is selected as the carrier for carrying knife carrier and connecting mechanism.Deformation characteristics of gantry structure is analyzed and its moving process is controlled synchronously.The main contents of this paper are as follows:(1)Aiming at the bending and torsion deformation of gantry structure in static state,the theoretical deformation formula under dangerous condition is deduced,and the specific theoretical deformation value is obtained.Then the finite element model of gantry structure is established in ANSYS,and the maximum deformation value is solved,the value and the theoretical calculation are checked mutually.The influence of displacement deviation caused by bilateral asynchronism on the overall deformation of gantry structure's moving process is analyzed.(2)Parametric modeling based on APDL language is given.And the paper improved and optimized the deformation of gantry structure.Taking the quality,flexural strength and torsional strength of gantry structure as the optimized objective,the strength and deformation conditions satisfying the requirements are designed.The Subproblem optimization method and the First-order optimization method are used to analyze different variables and objective functions twice,and the optimization results are analyzed.The deformation diagram and equivalent stress diagram of the optimal solution are given.Compared with the original structure without optimization,the gantry structure with smaller deformation and lighter weight is obtained.(3)Aiming at the asynchronism of gantry structure in moving process under external disturbance,the dynamic model of gantry structure of the NC cutting soft slices machine is established.The first is PID control method.The best P,I,D parameters and feed-forward parameters are obtained.The angle and speed error diagrams of bilateral drive motor are obtained.Then,aiming at the deficiencies of PID control,the sliding mode variable structure controller is designed.The cross-coupling control method is adopted.Though the simulation by MATLAB-Simulink,the control law with fast response,small angle and speed errors of bilateral drive motors,improved chattering phenomenon and strong anti-jamming ability is designed.The dead zone characteristics of the controlled system are discussed.After comparing the two control methods,the sliding mode variable structure control with higher control precision and better robustness is selected.Then the good effect of sliding mode variable structure control in practical application is verified by experiments.