Steering Magnetic Particles by Feedback Control of Permanent Magnet Manipulators

Noncontact magnetic manipulators are used in a range of medical, microrobotics, and microfluidics applications to operate magnetized tools from a distance without mechanical contact. The dominant trend in the design of these devices is to produce and control magnetic fields using electromagnets, while permanent magnets can produce much stronger magnetic fields for similar magnet size, weight, and cost. This advantage can be exploited to develop more compact, more effective, and less expensive magnetic manipulators. This paper briefly describes the conceptual design of a magnetic manipulator which utilizes an array of permanent magnets and mechanical actuators to control its magnetic field, and consequently, its magnetic force applied to magnetic particles. A nonlinear feedback control law is designed which enables this manipulator to steer magnetic particles along reference trajectories with reasonable precision.