Design of Magnetic Feet for Climbing Robot with Novel Circular Halbach Net EPM Structure

The magnetic foot module is the hardware core of leg-based magnetic climbing robot. To realize versatile mobility on large complex steel structures, the holding force density, energy consumption and sensing capability of magnetic foot are crucial. Here, we present a novel design of a magnetic foot that integrates the electro-permanent magnet (EPM), friction foot pad and flexible pressure sensor. Inspired by the Halbach magnet array, we propose a EPM with Circular Halbach Net structure (CHN-EPM). Due to the utilization of the flux concentration effect, CHN-EPM has a higher holding force density and faster electromagnetic response of magnetic flux switching than the traditional EPM structure. The magnetic holding force can be measured by the flexible pressure sensor between the friction foot pad and the CHN-EPM. The holding force and magnetic switching capacity of the magnetic foot have been verified by theory, FEM and experiment.