Mathematical modeling and design considerations for designing voice coil motor

The voice coil motor is a device motivated by electric current.It is creating force by Lorentz force principle generated by interaction of the current and magnetic field from magnets.The voice coil motor has been used for various purpose such as speaker, actuator, and etc. Especially, there has been numerous types of voice coil motors for actuators.Among those, a common type of voice coil motor which has wounded coil in the center covered with Halbach magnet array with iron yoke is object system of interest to be mathematically modeled.In this paper, the voice coil motor of the type is to be mathematically designed with Lorentz force principle.Since the Lorentz force is generated from current flowing in coil and magnetic field from magnets, method for analysis of magnetic field and of coil is described.Lorentz force is proportional to current.Therefore, final design variable to be found is a motor constant which is ratio of force to current.