Dynamic Characteristics of a Bistable Linear Actuator with Moving Permanent Magnet

The dynamic characteristics of an axisymmetrical linear actuator with axially magnetized moving permanent magnet are obtained using combined field and circuit approach. The magnetic field of the actuator has been analysed using the finite element method over a current-displacement sampling grid. Two field analyses are carried out for each point of the grid one for the real system and one for the system where the permanent magnet is considered as a soft magnetic body. For each point of the grid, data for the total flux linkage, electromagnetic force and the coil inductance are extracted from the magnetic field analysis. These data are approximated by bicubic spline functions, which are employed in the solution of the system of ordinary differential equations of the electrical circuit and the mechanical motion. Results are obtained for the time variations of the coil current, mover displacement, mover velocity and electromagnetic force. The results for the current and displacement are verified experimentally.