Characterization of current-flux and current-force relationships in reluctance actuators for high-precision applications

Due to their high output power density compared to Lorentz actuators, reluctance actuators have been increasingly employed in high-precision applications, such as lithography machines. However, the strong nonlinearity between the input current and the output magnetic force remains a challenging modeling task, which can significantly reduce control accuracy. This work presents an experimental characterization of the current-force relationship of a custom-made reluctance actuator. The current-to-flux and the current-to-force hysteresis nonlinearities are investigated in this study under various air gaps.