An experimental investigation on the performance of novel NdFeB-based composite material for magnetic encoding of road environment information

Abstract

Magnetic encoding technology, which can memorize and transmit road environment information to automated vehicles (AVs) in a stable and easily detectable way, could be a promising solution to enhance the safety redundancy of AVs. In this study, a NdFeB-based composite material, which can produce detectable permanent magnetic fields and be mechanically accommodatable in a road pavement structure, is designed for road information encoding. VSM, SEM, mechanical strength tests, as well as customized magnetic field distribution tests and obstacle interference tests, were performed. The following conclusions are drawn: (1) the NdFeB-cement composite has considerably high coercivity, remanence, and maximum magnetic energy product, the values of which could be as close as to that of the commercial ferrite permanent magnets; (2) the designed coding unit has a surface magnetic field up to 30 mT, and can produce a magnetic flux density of 4–5 times of the geomagnetic field at a vertical distance of 150 mm; (3) common pollutants on the road surface could hardly obstruct the detection of the magnetic fields generated by coding units; (4) the compressive strength and flexural-tensile strength of NdFeB-based composites can reach 58.4 MPa and 6.4 MPa respectively, which meet the mechanical requirements for road use.