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Long stroke magnetic levitation planar stages

University of British Columbia

Modern positioning applications often require long strokes in multiple degrees-of-freedom (DOF). One solution to such requirements is a planar stage capable of simultaneous large strokes in X- and Y-translation. An ideal stage concept is based on a planar motor which uses non-contact multi-axis forces to directly actuate a single moving body, without any connecting elements or bearings structures that would induce additional structural modes as well as excess inertia. This thesis presents the design, analysis and experimental results of two planar motors: 1) a permanent magnet synchronous planar motor, and 2) a permanent magnet asynchronous planar motor. The permanent magnet synchronous planar motor is comprised of multiple one-dimensional (1-D) magnet arrays attached to a moving stage and multiple stationary 1-D coils built as a printed circuit board (https://www.youtube.com/watch?v=-r4Tv7GbB8o). This motor addresses many issues with existing synchronous planar levitation motors, including scalability of the XY stroke with minimal increase in controller or drive complexity, and simplified commutation and control due to natural force/torque decoupling and no coil/magnet array edge effects. Modeling, analysis and design of a prototype are shown with motion control results. To use this levitation motor for high accuracy positioning applications, force and torque characteristics of the 6-DOF stage must be highly linear in all axes in order to minimize controller effort and reduce intrinsic motor disturbances. Novel magnet array designs are presented which self-attenuate both force and torque ripple in all 6-DOF, without additional controller or drive complexity. These array designs are tested via simulation and experiment. The permanent magnet asynchronous planar motor is based on the asynchronous induction effect to simultaneously levitate and propel the motion stage. The advantages of this type of planar levitation motor are: 1) passive stability in all axes; and 2) simple slab-type homogenous stator comprised of a basic conducting material such as aluminum or copper. This thesis presents novel modeling and analysis and provides a new analytical expression for the generated levitation force and torque with geometric and material property inputs. Experimental force and torque measurements are carried out and compared to the analytical model.

Text

2020-07-31

Attribution-NonCommercial-NoDerivs 2.5 Canada

http://hdl.handle.net/2429/55916

Mechanical Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/2.5/ca/