The Design Of Small Aspect Ratio Multi-axis Automatic Lock Screw Machine Motion Control System

As digital devices such as car-mounted televisions are increasingly appearing in automobiles,and these electronic devices typically use small aspect ratio screws for locking and securing internal components.However,at present,enterprises still rely on the manual operation,which usually using electric screw-tightening tools to lock the screws,as the main mode of production.With the increase in labor costs and the improving quality requirements in product,companies began to seek small length-diameter ratio of automatic locking device to replace the manual tightening.In this paper,the motion control system of small aspect ratio multi-axis automatic lock screw machine is designed to realize the high efficiency locking of small aspect ratio screw.First,the control scheme and electrical system of small aspect ratio multi-axis automatic locking screw machine are designed.The key electrical components are selected and the wiring of electrical system is completed.A prototype of multi-axis automatic locking screw machine with small length-diameter ratio is designed.The prototype of the machine is provided with the hardware foundation for the development of motion control software of small aspect ratio multi-axis automatic locking screw machine.Second,using the dynamic link library of motion control card to develop the motion control software,and linear servo motor uses position control to realize quickly and accurately positioned,and tighten the screw torque control method can accurately determine the screw tightening.Screw drivers can obtain their movement position through the workpiece information saved in the PC,and then they can achieve locking the small aspect ratio screw automaticly.Thirdly,Based on the motion coordinate system of the equipment,the key points in the motion process are selected through analyzing the mechanical structure.Then the curve fitting is carried out by MATLAB,and the path equation is solved to optimize the motion path.Fourth,the path optimization results are evaluated by experiments.The time and the vibration of the lock were tested,and the time and the vibration of the machine of locking the same workpiece before and after the optimization was compared to judge the effect of the path optimization.This project completed a electrical control system of small aspect ratio multi-axis automatic lock screw machine prototype and a set of the motion control software.Through experiments of locking 48-inch TV screws,after optimizing,the maximum speed of the multi-axis automatic locking screw machine can be up to 19.08 s in average,which is shorter than manual operation,the success rate is 98.5%,which can meet the requirements of enterprises.