Simultaneous Independent Translational and Rotational Feedback Motion Control System for a Cylindrical Magnet Using Planar Arrays of Magnetic Sensors and Cylindrical Coils

This letter describes an electromagnetic feedback control system for rigid-body motion control of a magnet. Its novel features are that sensing and actuation using magnetometer sensors and actuator coils operate simultaneously. Magnetic field models from the controlled magnet and each of the actuator coil currents are used together to calculate the three-dimensional position and orientation of the magnet. Motion is controlled simultaneously and independently in multiple degrees of freedom, including planar translation and two in rotation, leaving rotation about the cylindrical axis of magnetization uncontrolled. The system configuration and the localization and actuation methods are presented, together with experimental results of magnet localization with constant and varying coil currents, and during feedback control of trajectory-following motion of the magnet in multiple directions on a planar surface and with controlled changes in orientation. The intended application of the system is for motion control of magnetic endoscope capsules and other miniature medical devices inside the human body.