Simulation And Experimental Study On Magnetic Fluid Acceleration Sensor

As a new type of functional material,magnetic fluid not only has the magnetic property,but also has the flowability of fluid.It has been used in numerous fields for novel applications and the magnetic fluid sensor is an important aspect of its application.The application of magnetic fluid to the sensor can improve the sensitivity,linearity,and reduce the volume of the sensor.In this paper,the acceleration sensor as the research object,combined with the characteristics of magnetic fluid,the magnetic fluid acceleration sensor is designed.Its structure size is optimized,and its performance is tested by experiments.The main research contents are as follows:Firstly,in the finite element software Comsol,the simulation model of the magnetic fluid acceleration sensor is established and the function of the Hall element output characteristic curve is built.The relationship between inertia mass displacement and restoring force,displacement and output voltage of the sensor is numerically calculated.The relationship between the acceleration and the output voltage of the sensor is obtained according to the relationship between force and acceleration.So,the sensitivity and the range of the sensor can be calculated.The linear relationship between the restoring force and displacement can be used to obtain the equivalent elastic coefficient of the magnetic spring.Then the natural frequency of the sensor can be calculated by the formula.Secondly,the structure of acceleration sensor is optimized by orthogonal test.The size of the sensor structure parameters: the length of the permanent magnet,the return distance,the location of the Hall element and Hall element height are used as orthogonal test factors.The sensitivity,natural frequency and range of the sensor are taken as the three indexes to evaluate the test results.The comprehensive performance of the sensor was evaluated by the comprehensive weighted scoring method.The influence of the parameters on the sensor performance was analyzed by the range and variance method.On the basis of the orthogonal test data,the BP neural network is used to map the function relationship between the sensor size parameter and the performance index to realize the sensor output performance prediction.Finally,the static and dynamic characteristics of the sensor are investigated experimentally,in which the dynamic characteristics include sinusoidal response and step response.The static output sensitivity and range of the sensor are consistent with the finite element simulation results.The sinusoidal response of the magnetic fluid acceleration sensor output waveform,spectrum and contrast acceleration sensor is basically the same.The natural frequency of the sensor calculated by the step response experiment is close to the simulation value,and the damping ratio of the sensor is close to the theoretical value.