Motion Control And Experimental Of High-Speed And High-Precision Mass Transfer Platform

In the field of new generation display technology,with the gradual miniaturization of LED light-emitting chips,it becomes more and more difficult to achieve high-speed and high-precision transfer.The traditional mass transfer platform uses a non-collocated suction method to transfer the Mini LED chip,which increases the movement stroke and time spent during the transfer period,greatly reduces the chip transfer rate,and also limits the size of the transferable chip.The co-location transfer scheme based on the linear motor direct drive system has the advantages of short transfer cycle,fast response speed,and transferable Mini / Micro LED chips.It is an ideal solution to achieve high-speed and high-precision transfer.The research content and current situation of the mass transfer technology of Mini LED chips at home and abroad are introduced,and summarizes its development trend.In this paper,a dual-platform cooperative motion structure scheme of a co-location mass transfer platform is proposed.The structure and working principle of the mass transfer platform are introduced,including the ’H’ type crystal carrier platform and transfer principle of Mini LED chip,the ’+’ type platform and working principle of PCB solid crystal,the high frame rate CCD camera positioning system and working principle and SMC system and working principle.The main works about this study are as follows:(1)The topology,material characteristics,electromagnetic field and electromagnetic thrust of the DUPMSLM are analyzed,which lays a mechanical and electromagnetic foundation for its short stroke motion control.The electromagnetic field analytical model of the DUPMSLM is established by applying the equivalent surface current method,and the electromagnetic thrust analytical model is established based on the current density distribution function.The mechanical structure size of the crystal platform is designed by the load weight and acceleration requirements,and the magnitude and uniformity of the air gap flux density and the end leakage phenomenon under different magnetic material conditions are compared and analyzed.Transient simulation analysis is carried out on the basis of static magnetic field simulation,including no-load simulation analysis,load simulation analysis and electromagnetic thrust fluctuation analysis.Finally,the magnetic density measurement experiment is verified.(2)In order to solve the problem of parameter dynamic change of DUPMSLM transfer function model and low identification accuracy of traditional methods,a system identification method based on stochastic model is proposed.The system characteristics in the motion process are analyzed,and the structure and order of the transfer function model are determined.Aiming at the possible system disturbance of the system,the Box-Jenkins model with random disturbance term is selected,and the Levenberg-Marquardt algorithm is used for iterative optimization to find the optimal model parameters.By designing system identification experiments under different sampling frequencies,different injection current amplitudes and different motor speed conditions,the parameter identification results are analyzed.Finally,the design of the experimental platform and the input signal is introduced and explained.(3)In order to improve the transfer rate of Mini LED chip and shorten the movement time as much as possible while maintaining the accuracy of DUPMSLM,a triangular S-symmetric speed curve considering the accuracy setting time is designed.Based on the analysis of the characteristics of the traditional trapezoidal velocity curve and the S-shaped velocity curve,the static and dynamic modal simulation analysis is carried out,and the time-optimal objective function is designed in combination with the setting time.According to the x-axis machine vision positioning stroke and the mass transfer actual working condition stroke requirements of the Mini LED chip carrier platform,independent motion parameter planning is performed,and simulation analysis based on the traditional PID motion controller is performed.(4)The motion control of DUPMSLM under high frequency repetitive point-to-point short stroke condition is studied.Based on the time optimal speed curve planning,the DUPMSLM three-loop vector controller is designed.The structure of the controller includes current loop,speed loop and position loop.The speed loop adopts sliding mode controller,and the position loop adopts fuzzy PID controller.At the same time,the three closed-loop vector control model based on mechanism modeling is built by MATLAB/Simulink,and the simulation analysis is carried out.Subsequently,the short-stroke repetitive motion positioning accuracy test and the transfer test of the Mini LED chip of the mass transfer platform are carried out to verify the effectiveness of the proposed new motion control algorithm.It can not only realize the long-stroke macro-stability function,but also meet the short-stroke micro-activation requirements,which is in line with the motion control development trend of the mass transfer platform.Finally,the upper computer motion control software of automatic Mini LED chip mass transfer equipment based on C# is developed,and the function design and implementation are carried out.