A novel coil configuration to extend the motion range of Lorentz force magnetic levitation devices for haptic interaction

Lorentz force magnetic levitation devices have been used for fine positioning, compliant assembly, force- reflecting teleoperation, and haptic interaction. The advantages of Lorentz levitation devices compared to motorized linkage and/or cable devices include the lack of friction, hysteresis, and other nonlinearities in actuation dynamics, the simplicity and robustness of a single moving part, and the potential for high closed-loop control bandwidths, a large impedance range, and precise motion. The principal disadvantage of existing Lorentz levitation devices is their motion ranges of 25 mm or less in translation and 20 degrees or less in rotation, which limits their utility in application domains such as haptic interaction. In this paper a novel coil and magnet configuration is presented which extends the possible motion range of Lorentz force magnetic levitation devices to 50 mm and at least 60 degrees, twice the present maximum range in translation and three times the maximum rotation. The motion range of the device design is confirmed through computer-aided design models and the levitation feasibility is shown through magnetic finite element analysis.