The relative perception system of underwater bionic vehicles based on the artificial lateral line pressure sensor array

The lateral line system (LLS) is a unique sensing organ of fish. With the help of LLS, fish can communicate and school underwater based on the flow field information even in darkness. Inspired by the LLS, an artificial lateral line system (ALLS) mounted on the bionic vehicle was proposed in this paper to facilitate the research of bionic vehicle mutual perception. Specifically, the proposed ALLS was expected to find out the variation of pressure signals of the carrier vehicle during swimming alone or with others. Accordingly, the pressure distribution and transition of vortex streets generated by the oscillation of the bionic tail fin could be revealed. Firstly, the computational fluid dynamics (CFD) simulation was adopted to obtain the relationship between the ALLS pressure signal and the bionic vehicle swimming state when the vehicle was swimming alone. In this case, the swimming state involved the swimming velocity, the bionic tail oscillation frequency, and the bionic tail oscillation amplitude. Next, the ALLS pressure signal variation was captured when the ALLS carrier vehicle was swimming behind a leader bionic vehicle synchronously. The signal diversity between the two cases was explored. Lastly, the hardware of the bionic vehicle and the experiment platform were established to further compare the ALLS pressure signals of the bionic vehicle in both the cases of swimming alone and swimming together with a leader. The empirical mode decomposition (EMD) and back propagation neural network (BPNN) methods were adopted to extract features and distinguish the motion state of the vehicle based on the experiment platform. The feasibility and efficiency of the ALLS to perceive the motion of the carrier vehicle and the leader vehicle were validated in the simulation and experiment results. The conclusion of this paper should show a new promising inter-perception way for the underwater bionic vehicle cluster.