Modeling and characterization of a voice coil motor

Abstract

This thesis describes the development of a voice-coil motor that will allow viscous fluids to be delivered via a portable needle-free injection device. The chosen motor design features opposing magnets whose flux is channeled across the air gap by a center radial magnet, thus creating a higher flux density in the gap compared to a one-magnet design. An analytical model is developed which gives the force of the motor based on the material properties and geometry. An optimized geometry is modeled using finite element analysis, which predicts a motor constant of 11.02 N/[the square root of]W. The motor is fabricated and characterization reveals it to have a motor constant of 8.43 N/[the square root of]W. Althought the motor constant is less than expected, it is a large improvement over the current motor used in needle-free injection, which has a motor constant of 3.21 N/[the square root of]W.