A Novel Ferrofluidic Inclinometer

Inertial transducers based on the use of ferrofluidsas inertial mass can be of great interest due to their peculiaritiesand due to the advantages that they show when compared totraditional devices. Ferrofluids are special solutions of magneticparticles in a carrier liquid whose density and other physical featurescan be controlled by an external magnetic field. In this paper,the development of a ferrofluidic inclinometer, which exhibits atunable operating range and a valuable metrological feature andan intrinsic robustness against inertial shocks, is presented. Thedevice consists of one excitation coil and two sensing coils woundaround a glass pipe where a drop of ferrofluid is contained in awater environment. The magnetic force, which is induced by theexcitation coil, attracts the ferrofluidic mass in a position thatdepends on the device inclination. The voltage at the output of thetwo sensing coils is related to the ferrofluidic mass displacementand thus reflects the tilt to be measured. Analytical models, simulations,and experimental results are presented to demonstrate thesuitability of the proposed approach.