An artificial lateral line system using IPMC sensor arrays

Most fish and aquatic amphibians use the lateral line system, consisting of arrays of hairlike neuromasts, as an important sensory organ for prey/predator detection, communication, and navigation. In this paper a novel bio-inspired artificial lateral line system is proposed for underwater robots and vehicles by exploiting the inherent sensing capability of ionic polymermetal composites (IPMCs). Analogous to its biological counterpart, the IPMC-based lateral line processes the sensor signals through a neural network. The effectiveness of the proposed lateral line is validated experimentally in the localization of a dipole source (vibrating sphere) underwater. In particular, as a proof of concept, a prototype with Body Length (BL) of 10 cm, comprising six millimeter-scale IPMC sensors, is constructed and tested. Experimental results have shown that the IPMC-based lateral line can localize the source from 1-2 BLs away, with a maximum localization error of 0.3 cm, when the data for training the neural network are collected from a grid of 2 cm by 2 cm lattices. The effect of the number of sensors on the localization accuracy has also been examined.