Flat guidance schemes for magnetically levitated high-speed guided ground transport

Abstract

A magnetically levitated high-speed vehicle requires a noncontact guidance system. Guideway configurations are discussed, and the possibility of achieving guidance from a flat surface is investigated. A vehicle with electrodynamic suspension and linear synchronous motor propulsion carries superconducting magnets which may be used for guidance purposes. Eight possible ``flat'' guidance mechanisms are examined. It is shown that the interaction between vehicle-borne magnets and levitation strips or linear synchronous motor (LSM) windings cannot provide adequate restoring forces. Additional conductors are therefore required for guidance. The use of either vertically mounted rectangular loops or horizontally mounted null-flux (NF) loops under either the levitation magnets or propulsion magnets is therefore examined. The most promising system involves the interaction between propulsion magnets and horizontal NF loops, with the interaction between propulsion magnets and the edges of the levitation strips providing backup guidance. The guidance characteristics are analyzed and checked by model impedance measurements, and it is shown that, for this system a lateral stiffness of 106 N/m can be achieved.