Research On Magnetic Field And Output Characteristics Of Magnetostrictive Polishing Device

Magnetostrictive material has the advantages of large strain,high energy,fast response and so on.The material can be made of the transducer,actuator and other precision instruments,which can convert electromagnetic energy into mechanical energy.These devices can be widely used in electronics,machinery and precision machining and other fields.A magnetostrictive polishing device made of iron gallium is designed,which is composed of a magnetostrictive actuator,a base,a polishing device and some coils.The magnetic circuit structure of the driving element is analyzed.The material and geometry size of the magnetostrictive rod,the applying method of the based magnetic field,the wire diameter and the number of turns of the driving coil are determined.By using the finite element software to analyze internal magnetic field distribution of magnetostrictive rod.Three dimensional static magnetic field simulation is carried out,the results show that the uniform magnetic field accounts for about 89% of the whole magnetostrictive rod,which indicates that the driving device has high magnetic field strength and good uniformity.The magnetic flux flow in the magnetostrictive rod is analyzed through the finite element simulation of the dynamic magnetic field and the basic law of the flux flow is summarized.The driving circuit of the device is designed.The static output characteristic of the magnetostrictive polishing device is analyzed.Based on the coupled field theory,the static output characteristic of the device is simulated with the numerical simulation technology and the relationship between the end displacement and the current of the magnetostrictive rod is obtained.The prototype has been manufactured and static test system is set up.The static test includes the axial output displacement characteristic and the radial displacement characteristic of the magnetostrictive polishing device.The results indicate that the radial output characteristic of the device is more stable than that of the axial output and the output displacement is greater.Finally,the dynamic output characteristics of the magnetostrictive polishing device are studied.The vibration mode of the device is obtained by means of modal analysis.Theamplitude frequency response characteristics of the device in vertical and horizontal direction are analyzed by finite element method.The dynamic output characteristics of the device are studied.And the control characteristics of the frequency,bias current and AC drive current are discussed.Experimental results indicate that the resonant frequency of the device is 480 Hz,the maximum output amplitude is 50 ?m.The frequency range is480Hz~540Hz,the amplitude can be adjusted in the range of 15?m~50?m.Theoretical and experimental results indicate that the magnetostrictive polishing device can be used in the polishing of small aperture aspheric optical parts.It has the advantages of small size,simple structure,low driving power supply,flexible control,high precision and high accuracy.