Abstract
In the conventional zero-power controlled electromagnetic suspension (EMS) systems, a magnet unit, which suspend a vehicle, is composed of electromagnets and a permanent magnet. The electromagnets are controlled to maintain air gap length between the magnet unit and the guide rail so that the attractive force due to the permanent magnet are balanced with the suspended weight of the vehicle. This means the number of magnet units must be equal to the number of kinetic degrees of freedom. Consequently, the vehicle needs the mechanism which gives every magnet unit adjustment of the gap length in accordance with the suspended weight.
The authors propose an improved zero-power control. This new technique can remove the gap adjustment mechanism from the vehicle. The improved zero-power control not only levitates a rigid body vehicle with arbitrary number of magnet units but also guides the vehicle without any guide magnets and the detectors under the guide-effective EMS system. The pair of the improved zero-power control and the guide-effective EMS system allow conventional EMS systems to be made more compact in size and lighter in weight. In this paper, the authors explain the principle of the improved zero-power control and clear the property of zero-power control.
