Optimization of an Electrodynamic Linear Actuator for Biometric Applications

This paper describes the configuration of a permanent magnet linear actuator for biometric applications and explains the basics of the methodology used to evaluate the actuator thrust. The methodology, based on analytical expressions of the magnet flux linkage, enables a fast and accurate evaluation of the axial force and can apply to any set of coaxial coils. The formulations are used to optimize the actuator configuration, in order to improve the thrust uniformity along the mover stroke, some technological design fulfilling some technological design constraints. Introducing an auxiliary set of coaxial coils, the optimization procedure enables a remarkable uniformity improvement. The results are verified by finite-element analyses, and the measurements performed on a prototype confirm the effectiveness of the design procedure.