Since air-gap displacement affects the output force of the E-shaped electromagnetic actuator and thus the efficiency of the active-passive vibration isolator greatly, displacement sensors with high reliability and low cost is in great demand. To achieve this goal, self-sensing tech-nique based on the actuator itself has been developed. This paper presents a reluctance net-work model (RNM) of the actuator and utilizes a statistical method to estimate the air-gap dis-placement thereafter. The structure of the model was built after looking carefully into the cor-responding finite element model (FEM) considering leakage. Then a system of nonlinear functions reflecting the magnetic circuit was formed with the same techniques as for an elec-tric circuit. In order to calculate the desired output voltage of the actuator using the proposed RNM, the parameters of the model were optimized by experiments. Finally, considering the characteristic of the inductance discovered by the RNM, a statistical method to find the air-gap displacement was utilized.
