Switchable magnets for robotics applications

Abstract

The goal of this work is to produce an optimized switchable magnet to be used in small robotic applications. A switchable magnet is a system which uses moving permanent magnets to change the magnetic flux path and switch on or off the magnetic attraction force. The most relevant magnetic holders are presented and their working principle is explained. Then, a switchable magnet model is introduced on the Comsol Multiphysics, a physics simulation software, to enable a better understanding of its working principles, and the effect of different design and material parameters on the attraction force of the unit. Still in Comsol more simulations are exposed with the goal of making a similar device in a smaller scale with the best holding force per unit mass, whose magnetic fields interact in a constructive or destructive way, changing the path of the magnetic flux. We then coupled this device with an actuator in order to control its state (on/off). Then, two robotic devices using the novel switchable magnet are designed. The first one is a holding mechanism for a climbing robot, whose design relies on electromagnets. The second one is a prototype of a climbing robot which moves like a scissor, taking advantage of two ends which contain switchable magnets. In both systems the application of switchable magnets has one clear advantage, that is, in contrary to electromagnets this device only consumes energy at the time of switching the force on and off. The purpose of these two applications is to demonstrate the potential of the switchable magnets and show their great advantage (only requiring power to switch between states): magnetic force control without constant power feed.