Nonlinear modeling and verification of an electromagnetic actuator with consideration of friction

Abstract

To acquire a perfect vibration isolating performance in the active controlled mount system, a precise model for the actuator is required. In this study, we introduce a novel nonlinear lumped parameter model of the electromagnetic actuator for the engine’s idling or low-speed condition. The model considers not only the nonlinear characteristics caused by the reluctant force, cogging force, and magnetic saturation but also the friction between the mover and the supporting parts. The LuGre friction model is employed to describe the friction during the mover’s reciprocating motion. Then, the quasi-static actuator force of the electromagnetic actuator under constant currents is measured to identify the nonlinear parameters of the model, so is the nonstationary actuator force measured to identify the parameters of the LuGre friction model. Finally, a specific experimental scheme is proposed for validation, in which a suspended ring-shaped iron is added as the actuator’s load. This configuration limits the displacement of the mover effectively, allowing the actuator operate at a frequency of 20–50 Hz and at a peak actuator force of about 8 N, which is close to the actual working condition of the active controlled mount in the engine’s idling or low-speed condition. The results show that the proposed lumped parameter model is able to predict the dynamic characteristics of the actuator precisely. The root mean square errors of the current and actuator force are relatively 3% and 10%, respectively.