Abstract: A new functional material—magnetic fluid which possesses both ferromagnetism of solid and flow properties of fluid, is applied in the research of the pressure difference sensor. Based on the research on the magnetism model and properties of magnetic fluid, the magnetization intensity of magnetic fluid in the experiment is tested and the magnetization curve is obtained. The principle of the pressure difference sensor with magnetic fluid is analyzed, and the mathematic model of the mutual inductance pressure difference sensor with magnetic fluid is built. The inductance and mutual inductance of the coils on the two arms of the U tube are calculated. The relationship between the sensitivity and the parameters used in the test is attained by simulation experiment, and the relationship curve between the sensitivity and the diameter of the U tube is drawn. The relationship between the input pressure difference and the electric potential of the coils is derived. The output electric potential is proportional to the input pressure difference. The smaller the radius of the magnetic fluid core rm and the diameter of the coil are, the higher the sensor sensitivity will be. The greater the magnetic permeability of the magnetic fluid is, the higher the sensor sensitivity will be. The theoretical value is in agreement with the experimental value. In the allowable error range, the designed sensor can work well.

Key words: Magnetic fluid, Pressure difference, Sensor, Closed-loop simulation, Desired-type driver model, HIL test, Incremental-type driver model, Trajectory prediction