Servo Control of Magnetic Gears

Abstract

This paper considers the analysis and application of magnetic gearbox and magnetic coupling technologies and issues surrounding their use in high performance servo control systems. An analysis of a prototype magnetic coupling is used as a basis for demonstrating the underlying nonlinear torque transfer characteristics, nonlinear damping, and “pole-slipping” features when subjected to overtorque (overload) conditions. It is also shown how pole-slipping results in a consequential loss of control. A theoretical investigation into the suppression of mechanical torsional resonances in transmission systems encompassing these highly compliant magnetically coupled components is included along with experimental results from a demonstrator drive train. Automatic detection of pole slipping and a reconfigurable controller are also investigated. By addressing these issues, the proposed techniques extend the application scope of magnetic gear/coupling technologies to more demanding applications than those hitherto considered possible-specifically, for use in servo control systems and high-bandwidth mechanical drive trains.