Multi DOF Non-Contact Manipulation Using Permanent Magnet Linear Actuation

This paper describes non-contact manipulation mechanism of multi-DOF (degrees of freedom) magnetically suspended system. This manipulation system uses unique suspension mechanism whose suspension force is controlled by air gap length. This mechanism is composed of permanent magnets and linear actuators. We study the stability of a 2 DOF suspension system which manipulate the object in the vertical plane. To analyze the stability of the system, we assume that the attractive force acts on the direction from the magnet tip to the center of the object, and is inversely proportional to the square of the air gap length. In this paper, the principle of the suspension mechanism is explained and a prototype 2 DOF system is introduced. We make a linearized model of the system and the feedback gains are calculated by linear control theory. Numerical simulations on the nonlinear 2 DOF system are carried out. In experimental system, the magnetic field analysis is investigated on the system by an integral element method and the characteristics of the system are studied. Non-contact suspension is examined experimentally. Numerical and experimental results support the feasibility of the multi-DOF non-contact manipulation system.