The Application Of Magnetic Fluid To Tilt Angle Sensor

This paper plans to do the research of tilt angle measurement from a new point of view and using a new method. Because of magnetic fluid is a new functional material that has both fluid mobility and magnetic property, the principle is to use magnetic fluid as a sensing medium. The magnetic fluid can induce the slight change of magnetic field that caused by the tilt angle, so it can be used to measure the tilt angle. The tilt angle measurement has important and special meaning, and magnetic fluid tilt angle sensor has the advantage of its simple equipment, responsive, and low cost, so the research of this paper will have a significant and broad application prospect in the aviation, aerospace, railway, highway, oil exploitation and other fields.In this paper, the preparation of magnetic fluid, the related theories of tilt angle sensor and the new type of magnetic fluid tilt sensor structure has been expounded. On the aspect of experiments, the paper analyzes the crystalline phase of Fe3O4 powder that used in the magnetic liquid preparation by using XRD, and has a test of particle size of magnetic fluid on the laser particle size analyzer, also has a test of rheological properties of magnetic fluid on a rotating rheometer. A series of performance parameters of magnetic fluids have been got. Then based on the performance test, the testing experiments of magnetic fluid tilt angle sensor model have be completed by the sensor test platform that designed by our research group. The paper analyzes and discusses the saturation magnetization, viscosity, magnetic liquid volume and other performance parameters of magnetic fluids effect on the output results of the magnetic fluid tilt angle sensor.The results show that:1) Magnetization and viscosity of the magnetic liquid are the important parameters that affect the sensor performances, especially the sensitivity of the sensor. But their impact is not consistent, they are constrained and has a certain range.2) Under normal circumstances, the impact of magnetization is greater than viscosity, sensitivity of the sensor becomes higher when the saturation magnetization intensity is higher. Generally the magnetic fluid with a saturation magnetization intensity greater than 400Gs has a good performance on sensing.3) Rheological property of magnetic fluids is more complex, it has an influence on the response of magnetic fluid rheological properties. Low viscosity is conducive to the sensor response, but when the viscosity is too low, it leads to the decline in saturation magnetization.4)For the tilt sensors that have the same structural parameters, the volume of magnetic fluid has an effect on the best angle measurement range, when a magnetic liquid with better performance and its volume is 1.5mL, the best measure of range is about 10°～40°, when 2mL is about 0～20°. The larger of the volume, the best angle measurement range of the sensor decreases, but the corresponding sensitivity will increase.5) Performance testing of the several magnetic fluid tilt sensor shows that ester-based magnetic fluid has a better output characteristics of sensor as to its comprehensive performance compared with oil-based and kerosene-based magnetic fluid.