The dynamic model of levitation electro-magnet is the important part of levitation system. It is also the basis of levitation system stability control.

The paper gives the whole control system design of the in-pipe robot, which includes electro-magnet drive module, CPLD patulous module, wireless communications module, power module.

Another is to put a little coil of wire on top of a pigeon's head and use an electric current from a small battery to make an electro-magnet.