Magnetic gear dynamics for servo control

Abstract

This paper considers the analysis and application of magnetic gearbox and magnetic coupling technologies and issues surrounding their use for motion control servo systems. Analysis of a prototype magnetic gear is used as a basis for demonstrating the underlying nonlinear torque transfer characteristic, nonlinear damping, and ‘pole-slipping’ when subject to over-torque (overload) conditions. It is also shown how ‘pole-slipping’ results in 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 drivetrain. The automatic detection of pole-slipping, and recovery scenarios, is also presented.