Analysis Of Magnetization Characteristics And Thermal Effects Of Suction Chucks Based On Electronically Controlled Permanent Magnet Technology

Electronically controlled permanent magnetic suction chucks are widely used in lifting and mechanical industries,with strong magnetic suction force and easy operation.The hysteresis model of reversible permanent magnets is the key to accurate magnetic adjustment.Therefore,a new hysteresis model is established to adapt to the accurate dynamic adjustment of the hysteresis model under different excitations and to meet the requirements of variable magnetic suction force control.In addition,the coil passes into the current causing the temperature rise of the suction cup.The study of the limit temperature of the constituent parts of the suction cup can ensure the stable operation of the suction cup and further promote the application of electronically controlled permanent magnetic suction cups.The thesis research is as follows:The remanent magnetization of the reversible permanent magnet Alnico can be adjusted in real time by applying different pulse currents of different sizes and directions to the excitation coil of the electronically controlled permanent magnet chuck,thus changing the magnetic suction force.The remanent magnet adjustment is based on the non-linear hysteresis curve of Alnico.Applying the theoretical analysis method,the hysteresis curve of the magnetization process of Alnico under different external magnetic field strength is given,and the operating curves of the reversible permanent magnets under eight common operating conditions of the suction cup are analyzed to provide a theoretical basis for establishing the hysteresis model of the reversible permanent magnets.According to the hysteresis curves of reversible permanent magnets,a large number of local hysteresis curves appear inside the complete hysteresis curve due to the change of external magnetic field.The local hysteresis curves can be obtained by translational transformation of the complete hysteresis curve.Using the experimental measurement data of the complete hysteresis curve,the function of the local hysteresis curve is constructed by polynomial fitting,and the new hysteresis model is established by transformation.The new hysteresis model is validated by applying finite element software.Taking a four-pole electronically controlled permanent magnetic chuck as an example,different hysteresis curves were introduced and the relationship between the magnetizing current and the magnetic suction force and magnetic induction strength was analyzed to further prove the accuracy of the new hysteresis model.A thermal network model with compensation is proposed,taking into account the change in material properties of electronically controlled permanent magnetic chuck components as the temperature rises.For the four-pole electronically controlled permanent magnetic chuck,the nodes of the component parts are divided,the thermal resistance and power loss are calculated,the compensation coefficients are given,the thermal network model of the chuck is drawn,and the maximum temperature value of each node is found for different forward and reverse magnetization frequencies,and the nodal error is verified by finite element simulation to be within 10%.The results show that the measured values of the remanent magnetic strength and magnetic suction force at different magnetization states are in general agreement with the finite element calculations of the new hysteresis curve.The maximum temperatures of the reversible permanent magnets,main permanent magnets and coils were measured experimentally and compared with the results of the new thermal network model.The maximum temperature rise error of the suction cup components was 4.67%,verifying the accuracy of the model.