Research On Variable Force Clamping System Based On Electronically Controlled Permanent Magnet Technology

With the emergence and cost reduction of high-performance rare earth permanent magnet materials,electronically controlled permanent magnet technology has been rapidly developed and widely used.In the research of electromagnetic control of electronically controlled permanent magnet technology,there are few studies on accurately controlling the magnetization level of unsaturated magnetization of magnetic materials.The electronically controlled permanent magnet chuck designed based on the electronically controlled permanent magnet technology has the advantages of strong magnetic attraction,stability and energy saving.The electronically controlled permanent magnet chuck is applied to the workpiece variable force clamping,which can meet different process requirements and ensure the processing quality of the workpiece.Therefore,it is of great significance to study the magnetic control of electronically controlled permanent magnet chucks.Taking the variable-force clamping electronically controlled permanent magnet chuck as the research object,the key techniques such as the magnetic circuit analysis and calculation of the electronically controlled permanent magnet chuck,the mathematical modeling of the AlNiCo hysteresis curve and the design of the electronically controlled permanent magnet chuck controller were studied.The principle of magnetically controlled permanent magnet chuck and the calculation method of magnetic circuit are analyzed.The magnetic circuit of the electronically controlled permanent magnet chuck was modeled by the equivalent magnetic circuit method,and the relationship between the magnetization level of AlNiCo and the magnetic induction of the air gap of the electronically controlled permanent magnet chuck was obtained.The formula for calculating the magnetic attraction force is given,which provides a theoretical basis for the variable-force clamping of the electronically controlled permanent magnet chuck.The working trajectory of AlNiCo charging and demagnetization was studied.The mathematical model of the aluminum-nickel-cobalt hysteresis curve is established by using the Preisach hysteresis model.The relationship between the magnetic attraction force and the excitation current is given by combining the magnetic force calculation formula.And passed the finite element verification.The electronically controlled permanent magnet chuck controller is designed to realize the variable force control requirement by adjusting the excitation current.The controller was simulated and verified by the simulation software MATLAB/Simulink module.The controller was customized according to the design parameters,and the electronically controlled permanent magnet chuck experiment system was built.The magnetic attraction force of the electronically controlled permanent magnet chuck was measured experimentally,and the experimental relationship between magnetic attraction and excitation current was obtained.Compared with the theoretical results,the magnetic attraction has the same trend but a certain error.The developed electronically controlled permanent magnet experimental system can realize the application of variable clamping force.Finally,the experimental study of sheet metal deep drawing is carried out,and the magnetic force is adjusted online by the controller to realize the variable pressure side force control.