Research On Micro-displacement Adjustment Mechanism And Beam Lightweight Of Long-span Gantry Robot

With the development of economy and society,people’s pursuit of quality of life is constantly improving,and the demand for personalized customized wooden doors is also expanding,prompting wooden door processing enterprises to continuously improve the automation level and intelligent level of production line,in order to adapt to the needs of rapid and flexible production.Therefore,this paper presents a long-span,high-speed and high-precision curved-arm gantry robot for wood door industry.This paper mainly focuses on the design of gantry robot’s structure,kinematic analysis,dynamic analysis,error analysis,kinematic calibration and lightweight design of long-span beam.According to the operation characteristics of the wooden door processing line,the overall structure scheme of the gantry machinery is proposed.The configuration of the fine-tuning mechanism is synthesized based on the generalized function(G_F)sets theory.According to the working conditions and the characteristics of branch chains,the appropriate branch chains and their placement forms are screened out,and the appropriate mechanism configuration is obtained as the prototype of the fine-tuning mechanism.The motion performance of fine-tuning mechanism is analyzed.Its inverse position solution is analyzed by using vector closed loop,and its forward position solution is deduced by space geometry.Based on the position analysis results,the velocity Jacobian matrix and Hessian matrix of the fine-tuning mechanism are obtained by using the vector derivative method,and the correctness of the position,velocity and acceleration formulas is verified by the simulation model.The workspace of the fine-tuning mechanism is analyzed,and the mechanism parameters are optimized with the goal of workspace utilization.The error model of the fine-tuning mechanism is established.Combined with the statistical theory,the error sensitivity of the mechanism is defined and analyzed.The dynamic of the fine-tuning mechanism is analyzed.The statics mapping equation of the fine-tuning mechanism is established based on the principle of virtual work,and the carrying capacity of the fine-tuning mechanism in the working space is analyzed through the results of statics derivation.The motion and force of each member of the fine-tuning mechanism are analyzed.The dynamic equation of the fine-tuning mechanism is established by using the d’Alembert principle.The simulation model is compared with the theoretical derivation to verify the correctness of the theoretical derivation.Ten typical working conditions are selected to analyze the deformation,stress and modal of the fine-tuning mechanism and its key components by using finite element method.A calibration model based on the inverse kinematics solution is proposed.The problem of parameter identification of the fine-tuning mechanism is transformed into the problem of seeking the optimal solution of the nonlinear equation by the least square method,and the motion model of the control system of the fine-tuning mechanism is calibrated.The calibration experimental system is built based on the laser tracker.In order to improve the input precision of the fine-tuning mechanism,the input error of its driving system is compensated,and the kinematic parameters of the fine-tuning mechanism are identified.After calibration,the precision of the fine-tuning mechanism is evaluated,and the accuracy of the position distance of the fine-tuning mechanism which has a great influence on the precision of the gantry robot is up to 0.1mm.The high stiffness and lightweight beam of the gantry robot is topologically optimized.Aimed at the problems that the direct topology optimization of gantry robot beam is difficult to identify,a new method for high stiffness optimization of the long-span beam is proposed.Through the analysis of the beam load,the three-dimensional topology optimization problem of beam structure is transformed into two-dimensional optimization problem by using the functional section decomposition method,which reduces the difficulty of topology optimization.The moving load is simplified to multi-condition load,the comprehensive evaluation function is established by using the compromise programming method,and the multi-objective size optimization of the beam is carried out by using the genetic algorithm.The results show that the stiffness and strength are increased by 10%and 20%respectively while the weight of the beam is reduced.