Abstract:The stable levitation of permanent magnets in magnetic fluid has a wide range of applications in tilt sensors. In this article, a magnetic fluid inclination sensor using ring permanent magnets, soft magnetic metals, and non-magnetic metals as inertial mass is proposed. The magnetic fluid levitation force received by the inertial mass is used as restoring force. The magnetization effect of soft magnetic metals and the eddy current effect of non-magnetic metals are used together to increase the sensitivity of the inclination sensor. The soft magnetic and non-magnetic metals are used to wrap the permanent magnet to prevent damage under severe impact. The calculation formula is derived to calculate magnetic fluid levitation force, the influence of the axial length of inertial mass on the levitation force and coil inductance has been studied, and the effect of signal source frequency on the output voltage of the sensor is demonstrated. The magnetic fluid inclination sensor is used for the measurement of inclination. When the range of inclination angle is 0~42°, the linearity between the output voltage and the inclination angle is about 6.5%, the sensitivity is 5 mV/°, and the hysteresis is less than 1%.