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This paper presents the studies on an induction planar actuator. The device uses the same principles as a linear induction motor where the interaction between a travelling magnetic field and a conducting surface produces eddy current, which leads to the generation of a linear force. However, the planar actuator has travelling magnetic fields in two perpendicular directions and a combination of these can produce planar movement in any direction on a planar surface. This movement, combined with an inherent normal force between the planar actuator and a magnetic surface over which it moves, provides the adhesive force to allow the utilization of this actuator in a system for inspecting steel surfaces. Theoretical and numerical results are obtained and compared with results from a prototype. These results verify the operation of the actuator and validate the device with application potential.

This paper presents a study on an induction planar actuator concept. The device uses the same principles as a linear induction motor in which the interaction between a travelling magnetic field and a conducting surface produces eddy currents that leads to the generation of a thrust force and can result in movement over a metallic surface. This can benefit the inspection of metallic surfaces based on the driving platform provided by the induction planar actuator. Equations of the magnetic and electric fields are presented and, by means of these equations, the forces involved were calculated. The behaviour of thrust and normal forces was analysed through the equations and by numerical models, and compared with the results obtained by measurements on a device prototype built in the laboratory as part of the study. With relation to the surface under inspection that forms the secondary, three cases were analysed: (1) a double-layered secondary formed by aluminium and ferromagnetic slabs; (2) a single aluminium layer and (3) a single ferromagnetic layer. Theoretical and measured values of thrust and normal forces showed good correlation.