A moving coil linear oscillatory actuator is consisted of the NdFeB permanent magnets with high specific energy as the stator, a coil-wrapped nonmagnetic hollow rectangular structure and an iron core as a pathway for magnetic flux. The variation of mover position and the consequent changes of coil flux path affect the coil inductance, because coil flux leaks at the open region of LOA stator. The interaction between permanent magnet and armature field is to shift the airgap flux density variation due to the magnet alone by a certain amount. The unbalanced reciprocation force due to armature reaction field decreases the advantage of moving coil LOA, such as a high degree of linearity and controllability in the force and motion control. This paper firstly describes the coil inductance, the deviation of flux density, and the unbalanced reciprocation force, which are derived form the permeance model of LOA. Secondly the analytical method are verified using the 2D finite element method and tests. Finally, the dynamic simulation algorithm taking the armature reaction effect and variable inductance into account, is proposed and confirmed through the experiment.
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