Design of a Continuously Varying Electro-Permanent Magnet Adhesion Mechanism

The most common adhesion mechanism used in mobile robots, which are used for inspection tasks in ferromagnetic structures, is the magnetic adhesion mechanism. Magnetic adhesion can be produced by Permanent Magnets (PMs) or Electro-Magnets (EMs). Both of them have intrinsic limitations such as: a fixed magnetic force for PMs or the need of a constant electric power supply for EMs. These restrictions have a substantial impact on the performance of the mobile robot when manoeuvring in intricate structures, evading tough obstacles or energy consumption. Nevertheless, the work in this paper presents a novel approach to overcome these restrictions by employing Electro-Permanent Magnet (EPM) technology in the adhesion mechanism design. By simply applying a short electric pulse it is possible to switch On and Off the adhesion force. Furthermore, by controlling the amplitude of the pulse the magnetic force can be driven to a desired value between On and Off states, enabling the continuous variation of the magnetic force. The results validate the feasibility of the proposed design and consequently the potential use of EPM for adhesion mechanism in mobile robots.