Design, analysis and experiments of novel short-stroke linear loading system based on axial-magnetized voice-coil motor for linear oscillating actuator

Linear oscillating actuator is a kind of electromagnetic device, providing high frequency short-stroke reciprocating motion directly without extra motion transfer mechanisms. It shows satisfactory efficiency and power density especially with high frequency and large load. However, due to its special motion forms, researches into driving and control of linear oscillating actuator under loaded states are seldom conducted because traditional loading methods, such as magnetic powder brake and weight loading, are not suitable for high-frequency linear bi-direction loading applications. In order to deal with this problem, a novel linear loading system based on voice-coil motor is proposed in this paper to facilitate comprehensive testing and control of linear oscillating actuators with load. To achieve fast response, low inertia and stable loading force, symmetrical axial-magnetized array is adopted among the various magnetic configuration solutions. Moreover, non-ferromagnetic and non-conductive mover is designed for both low inertia and eddy current suppression. For validation, magnetic circuit configuration is firstly analyzed and leads to the analytical model of flux density and thrust. Based on the model, detailed structure optimization is conducted to instruct prototype design. Finally, complete experiments of proposed loading system is presented, including static output and thermal distribution. And it is expected to provide a practical solution to similar linear loading applications.