5-DOF Real-Time Control of Active Electrodynamic MAGLEV

TLDR: Control of the multi-DOF trajectory of a passive sled by active control of the coil currents is shown, using both a sliding mode controller with nonlinear input mapping from coil currents to levitation forces, and a multi- DOF nonlinear observer.

Abstract: This paper presents the five degree-of-freedom (5-DOF) control of an electrodynamic MAGLEV suspension with active control of the levitation coils. A sled with built-in permanent magnets moves past an array of fixed coils to generate Lorentz forces that provide lift and guidance. When active control of the levitation coil currents is implemented, multi-DOF trajectory control can be achieved, leading to stable electrodynamic levitation that can actively reject disturbances independently of sled speed. This paper shows successful control of the multi-DOF trajectory of a passive sled by active control of the coil currents, using both a sliding mode controller with nonlinear input mapping from coil currents to levitation forces, and a multi-DOF nonlinear observer. The paper also compares the use of look up tables versus analytical models of the magnetic field density used to estimate the magnetic forces and torques acting on the sled. The performance of the proposed approaches is demonstrated experimentally.