Research on a Novel Ferrofluid Inertial Sensor With Levitating Nonmagnetic Rod

This paper presents a novel inertial sensor with a movable nonmagnetic rod immersed in the ferrofluid, which can be used as a low band accelerometer. Movement of the nonmagnetic rod inside a container under the influence of external inertial forces will lead to the change of the ferrofluidic volume distribution. A couple of sensing coils detect the change and a corresponding signal occurs. The nonmagnetic rod with a dumbbell-shaped structure improves the linearity and stability of the sensor. The specially arranged permanent magnets create a non-uniform magnetic field, which generate a powerful restoring force determining the position of the nonmagnetic rod. The restoring force is performed by means of the comparison between experimental measurements and theoretical calculation. Compared with the conventional ferrofluid inertial sensors, one of the most significant advantage of the proposed device is that it can be applied in the magnetic environment.