The Theoretical and Experimental Study of a Ferrofluid Inertial Sensor

In this paper, an inertial sensor exploiting the self-levitation of a magnetic object immersed in ferrofluids is presented. The ferrofluid absorbed on the magnetic object produces an unusual buoyant force that resists gravity and serves as an elastic force. When the magnetic object moves under an external perturbation, the elastic force tries to return the magnetic object to its initial position. Therefore, the analysis of the buoyant force is the key to ensuring that the inertial sensor can achieve the excellent static performance. A series of simulations and experiments are used to optimize the buoyant force. Furthermore, the stable levitation height of the magnetic object is determined, and the influence of the ferrofluid mass on the buoyant force is studied. The comparison between numerical calculations and experimental measurements shows a good agreement. The satisfactory linearity and high sensitivity indicate the feasibility of the ferrofluid inertial sensor.