A study on flow field characteristics of a self-propelled robot fish approaching static obstacles based on artificial lateral line

Abstract

To perceive the static obstacles in still water, the flow field characteristics of a self-propelled robot fish approaching static obstacles were studied based on Artificial Lateral Line(ALL). The pressure distribution on the fish body surface was calculated with different separation between the robot fish and the obstacle boundary, obstacle size and undulating frequency. Subsequently, an ALL system was established and five obstacle perception models were studied to analyze the perceptual characteristics of the ALL. Finally, the experiments were conducted to further reveal the effects of obstacles and motion parameters on the body surface pressure of robot fish. The results indicate that the obstacles have a significant effect on the pressure distribution of the surface of the fish body. Namely the parameters of separation, obstacle size and undulating frequency will affect the peak value of the amplitude envelope of the pressure signals. The obstacle size and distance between the obstacles can be predicted using the time parameters of the amplitude envelope of the pressure signals. Moreover, the self-propelled robot fish with a medium undulating frequency approach to the large obstacles with small separation has better perceptual performance. The findings could offer some insight into understanding the perception of complex underwater environment based on ALL.

Research on the application of artificial lateral line system for different sensing effects of fish

“…Because of its deflection sensitivity when stimulated by external forces, the superficial neuromast is regarded as a displacement sensor based on ciliated cells, which can realize the response to low-frequency DC signals. Under the impact of water flow, the superficial neuromast can sense the flow velocity and direction of water flow [20]. In a word, when the whole surface of the fish moves with the water flow, the ciliary cells on the superficiality of the fish in the original erect state start to lean, causing the nerve fibres under the cilia to generate stimulus signals, which are then transmitted from the nerve endings of the fish to the nerve centre, so that the superficial neuromast is equipped with the ability to obtain fluid strength and recognize direction information.…”