Research on locating of an in-pipe robot and optimizing of the locating system design

This paper presents a method for locating in-pipe robots. Based on the extreme low frequency (ELF) electromagnetic pulse, the method realizes the signal transmitting between the inside and the outside of metallic pipeline. The propagation model of the ELF electromagnetic field in the underground pipeline environment was devised. By simulation, the effects of environmental geometric size, electromagnetic parameters, and emitting frequency on the signal intensity outside the pipeline were studied. The ELF electromagnetic emitting system was simplified into a magnetic dipole model, and the tracking and locating of pipeline robots was accomplished by applying the sensor array system and the inverse calculation of the magnetic field. In order to reduce the imitation error between the magnetic dipole and the emitting coil, an optimum design method for the coil structure was studied. The propagation ability of ELF electromagnetic pulse and the presented locating method were verified by the field tests.