Dynamic Characterization Of The 5-DOF Magnetic Levitation Actuator For EDM

Electric discharge machining is suitable for processing various conductive materials,especially for hard and brittle materials and complex surfaces.However,the difficulty in quickly adjusting the machining gap during the EDM process has led to low efficiency.This paper analyzes the dynamic characteristics of a 5-DOF magnetic levitation drive that can be directly installed on an EDM machine tool for machining,and designs a corresponding control method to quickly adjust the machining gap,thereby increasing the number of effective discharges and improving the efficiency of the EDM machine tool.First,the electromagnetic force of the 5-DOF maglev drive was simulated and experimentally verified.A three-dimensional model of the maglev drive was established using3 D design software,and the working principle of the 5-DOF maglev drive was analyzed.Based on the 3D model,an electromagnetic force simulation model was simplified,and finite element analysis software was used for electromagnetic force characteristic simulation and experimental verification.The experimental results showed that the electromagnetic force of the 5-DOF maglev drive has good linearity.Based on the electromagnetic force simulation,a dynamic model of the maglev drive was established.Second,modal analysis and harmonic response analysis were carried out on the 5-DOF maglev drive.The natural frequencies and mode shapes of each order were analyzed,and the results showed that the seventh-order mode of the 5-DOF maglev drive has the largest amplitude,determining the frequency range in which the maglev drive will resonate and affect machining accuracy and service life.Then,a PID control method was used to design the control system of the 5-DOF maglev drive,and simulation analysis and experimental verification were carried out based on its dynamic model.After the control system of the 5-DOF maglev drive was designed and built,step response simulation and control experiments,sinusoidal tracking simulation and control experiments were carried out along the X-axis,Z-axis,and around the X-axis deflection direction.The experimental results showed that the 5-DOF maglev drive has good dynamic characteristics,such as fast response speed,short adjustment time,and good tracking performance.Finally,the EDM experiment system based on 5-DOF magnetic levitation actuator is designed and built,and the experiment is carried out with the aid of 5-DOF magnetic levitation actuator.The experimental results show that the effective discharge number of EDM with magnetic suspension actuator is obviously increased,and the efficiency of EDM is 16% higher than that of traditional EDM.And the machining efficiency of EDM increases with the increases of the frequency and amplitude of the drive tool.When the frequency and amplitude of tool lifting assisted by the magnetic levitation driver reach 5rad/s and 20μm respectively,the processing efficiency is greatly improved,which is 32.4% higher than that of traditional EDM.