Research On High-precision Motion Control Technology For MiniLED Sorting

LED sorting machine is one of the key equipment in the production process of LED wafer packaging.With the Mini LED era,the accuracy of the chip arrangement is becoming higher and higher.In this paper,the accuracy of the LED sorting process is studied from the master motor positioning error and the Angle error caused by the membrane.First,the master motor control algorithm controlling the swing arm is improved,and the speed feedforward + acceleration feedforward and TD filter are introduced based on the PID three closed-loop control algorithm.To obtain the mathematical model of the master motor,the experimental frequency domain method is used for modeling.In this process,by collecting the node graph data of the master motor,using the system identification toolbox and node diagram theory to determine the transfer function of the master motor.After comparison,it is found that the theoretical derived results are more than the toolbox.According to the simulation experiment of the optimization control algorithm in the simulink simulation environment,the simulation results show that the composite control algorithm can effectively improve the response speed of the control system,reduce the overregulation of the system,and significantly improve the control accuracy of the master motor.Secondly,it proposes a new wafer rotation angle compensation scheme for the wafer angle offset,introduces the basic principle of wafer rotation angle compensation,establishes the spatial model of wafer rotation angle compensation,and introduces the specific angle correction process in detail.Last,Design of the swing arm motion control system,Select the key hardware components of it,Experimental verification of the optimized PID three-closed-loop control algorithm in the constructed swing arm control system,The results of the experiments showed that,The improved control algorithm can significantly improve the positioning control accuracy of the swing arm;Then performed 500 consecutive sorting experiments on an LED sorter,Under the joint optimization of the swing arm positioning control accuracy and the wafer rotation angle compensation,Changes in the wafer alignment accuracy,The results of the experiments showed that,Joint optimization of the two aspects,Reducing the alignment error in the wafer X / Y direction from ± 30 to± 15,The angular error was reduced from ± 3to ± 0.5,The alignment accuracy of the wafers was significantly improved.