Study of the Second-Order Levitation Force in the Magnetic Fluid Accelerometer

The magnetic fluid accelerometer is a novel sensor based on the unique characteristic of magnetic fluid. The second-order levitation is one of the most significant physical phenomena of magnetic fluid, which usually plays a role of restoring force in magnetic fluid accelerometers. In this paper, the restoring force of an actual magnetic fluid accelerometer generated by the second-order levitation is analyzed theoretically and calculated by the finite-element method software. The theoretical model takes consideration of the two boundaries of the magnetic fluid area, which makes it closer to the reality. The calculation is in good agreement with the experimental result. Besides, the structure of the accelerometer is optimized based on the restoring force curve, and the linearity of the magnetic fluid accelerometer is greatly improved almost six times larger from 10.85% to 1.82% at a range of 0-1 g.