Design and Control of a Magnetically Suspended Ceiling Actuator with Infinite Planar Stroke

Abstract

Abstract. This paper presents the design and control of a magnetically suspended ceiling actuator which combines four iron-cored linear actuators and a checkerboard permanent magnet array for an infinite planar stroke. When the actuators are rotated with respect to the PM array, it is shown that the thrust and normal force produced by the three-phase linear actuators can be controlled by applying Park's transformation. The design of the iron-cored linear actuators is optimized for minimum losses when the translator inside the ceiling actuator and a payload are accelerated in the xy-plane. The optimization is performed using an analytical model is. Simulations of the optimized design with a 3D FE-model, show a maximum tracking error of 1 µm and rotations of 30 µrad when the translator is moved and controlled in 6 DOF.

Design and experimental validation of a magnetically suspended planar motor with integrated contactless energy transfer system

“…It leaves a mechanical clearance of 1 mm. The optimized design for the planar motor requires a low magnetic loading which results in a balance between the passive attraction force, the active normal force and the ohmic losses [4]. Furthermore, for an efficient operation of the CET system, only materials with a low electrical conductivity should be used in the neighborhood of the primary coils.…”

“…1. The ycomponent of the torque, T y , produced by a linear motor oriented along the x-direction, dependents on the position in the xy-plane and the three-phase currents [4]. This torque component is expressed as follows…”

“…The design of the planar motor is optimized for minimum ohmic losses in combination with a total translator mass equal to 10 kg and an acceleration of 5 m/s 2 [4]. Furthermore, to embed the primary coils of the CET system (1.5 mm thick) and a protective polyethylene sheet (0.5 mm thick) inside the airgap of the planar motor, the clearance between the permanent magnets and the linear motors is equal to 3 mm.…”

“…1. The translator embeds four iron-cored linear synchronous motors [4], which are arranged in pairs along the x-and y-direction and are rotated 45 degrees with respect to the structure of the alternating checkerboard PM array.…”