A Pressure Sensory System Inspired by the Fish Lateral Line: Hydrodynamic Force Estimation and Wall Detection

Studies have shown that many behavioral decisions of fish are facilitated by the lateral line system which provides hydrodynamic information about the surrounding fluid. Inspired by the functionality of the system, a distributed pressure sensory system is developed. The system is intended for use on autonomous underwater vehicles to aid station keeping and accurate maneuvering by allowing the vehicle to react to the changes in the fluid environment before they result in body perturbation. The system can also be used for mission level decision making such as obstacle detection. This paper presents a prototype sensory system using differential, as opposed to absolute or gauge, pressure sensors as the sensing elements, which allows for higher measurement precision. Experimental tests are designed to characterize the system's ability to estimate the hydrodynamic force and to detect the presence of a wall. The hydrodynamic force estimated by the system is validated with an independent force measuring apparatus. The impending wall could also be detected by analyzing the pressure distribution obtained from the sensory system. Particularly, it is found that the wall distance and angle may be inferred by comparing the amplitude and phase of the Fourier components in the pressure distribution against those without the obstacle.