Research On Motion Modeling And Precision Control Of Precision Five-axis Surface Dispensing System

With the rapid development of electronic products such as 3C(Computer,Communication,Consumer Electronic),the miniaturization and complexity of precision electronic devices have increasingly high requirements for dispensing technology.Due to the structural defects of traditional dispensing systems and the constraints of geometric errors of motion axes,there are problems such as low spatial dispensing accuracy,slow speed and poor continuity in precision dispensing.In view of this,this paper focuses on the design,modeling and control of a precision five-axis surface dispensing system for the above-mentioned complex surface dispensing system problem.The main research work is as follows.(1)In order to meet the requirements of high precision and continuous smooth dispensing trajectory in complex surfaces,this paper develops a precision five-axis surface dispensing system and conducts research on improving the spatial accuracy of dispensing and smooth processing of trajectory.The precision five-axis surface dispensing system integrates the motion control system unit,the vision system unit and the dispensing control system unit,and integrates and designs the software control program of each system unit.Finally,a physical prototype of the precision five-axis surface dispensing system is built and the operational reliability of the physical prototype is verified.(2)The kinematic modeling,error identification and compensation strategy of the five-axis precision dispensing stage are studied.Three common types of positive kinematic models of five-axis dispensing motion stages are unified using spiral theory,and the inverse multi-value problem of five-axis motion stages based on the Paden-Kahan subproblem is investigated,and an effective method is proposed to correct the inverse kinematic singular value jump phenomenon.The error calibration model of the five-axis precision dispensing motion stage is established based on the monocular vision posture detection method,and the identification scheme of the rotational axis geometric error term is studied;finally,the spatial error compensation strategies based on the spiral theory and the differential theory are proposed in order to improve the spatial dispensing accuracy comprehensively.(3)The smooth trajectory planning problem of five-axis dispensing system is studied.To address the problem of glue pile-up caused by low speed at the interface of the dispensing mechanism,a 3-5-3 segmented polynomial interpolation method is proposed to plan the dispensing trajectory in the joint space,which optimizes the interface performance at the transition point of the trajectory and verifies the smoothing superiority of the method at the simulation level;meanwhile,the feasibility of involute and spiral trajectory planning in the five-axis dispensing system is analyzed at the theoretical and simulation levels.(4)The error identification,spatial error compensation strategy and trajectory planning method proposed in the paper are combined to perform experimental verification on an actual five-axis motion dispensing system.The experimental results show that the mean value of position error is 0.0791 mm before and 0.0186 mm after calibration,and the mean value of direction error is 0.0030 radians before calibration,0.0008 radians after calibration.The experimental results show that the error calibration scheme,spatial error compensation strategy and trajectory planning method proposed in this study can effectively improve the spatial position accuracy of the five-axis dispensing motion platform and achieve smooth and continuous dispensing trajectory processing.