Modeling and Analysis of Eddy-Current Damping Effect in Horizontal Motions for a High-Precision Magnetic Navigation Platform

Recent advancements in micro/nano-domain technologies have led to a renewed interest in ultra-high resolution magnetic navigation platforms. A magnetic navigation platform (MNP) has been developed at the MagLev Microrobotics Lab of the University of Waterloo, Waterloo, ON, Canada. This platform consists of two separate basic components: a magnetic drive unit and a microrobot. The magnetic drive unit produces and regulates the magnetic field for noncontact propelling of the microrobot in an enclosed environment. The MNP is equipped with an eddy-current damper to enhance its inherent damping factor in the microrobot's horizontal motions. This paper deals with the modeling and analysis of an eddy-current damper that is formed by a conductive plate placed below the levitated microrobot to overcome inherent dynamical vibrations and improve motion precision. The modeling of eddy-current distribution in the conductive plate is investigated by solving the diffusion equation for vector magnetic potential. An analytical expression for the horizontal damping force is presented and experimentally validated. It is demonstrated that eddy-current damping is a key technique to increase the damping coefficient in a noncontact way and improve levitation performance. This damping can be widely used in applications of magnetic actuation systems in micromanipulation and microfabrication.