Sensing method on magnetorheological fluid concentration and in-situ settlement monitoring based on wire wound inductor

Aiming at the limitations of magnetorheological fluid (MRF) settlement monitoring in transparent non-metallic containers, a method of MRF concentration measurement based on a wire wound inductor is proposed in this paper, and with the sensing method, in-situ monitoring of MRF sedimentation inside the damper is fulfilled. The varying local concentration of MRF will lead to the inductance change of the wire wound inductor, which is immersed in the MRF at a specific position, with the settling process. When harmonically excited with a signal generator, the relationship between the output amplitude across the inductor and the MRF concentration can be established. To reveal the settling speed dependence, the monitoring of the MRF settling is carried out with different concentrations and viscosities. It is testified that the proposed method can measure the concentration of MRF effectively, and is qualified with the in-situ monitoring of the MRF settling in a real damper.