Localization of source with unknown amplitude using IPMC sensor arrays

Abstract

The lateral line system, consisting of arrays of neuromasts functioning as flow sensors, is an important sensory organ for fish that enables them to detect predators, locate preys, perform rheotaxis, and coordinate schooling. Creating artificial lateral line systems is of significant interest since it will provide a new sensing mechanism for control and coordination of underwater robots and vehicles. In this paper we propose recursive algorithms for localizing a vibrating sphere, also known as a dipole source, based on measurements from an array of flow sensors. A dipole source is frequently used in the study of biological lateral lines, as a surrogate for underwater motion sources such as a flapping fish fin. We first formulate a nonlinear estimation problem based on an analytical model for the dipole-generated flow field. Two algorithms are presented to estimate both the source location and the vibration amplitude, one based on the least squares method and the other based on the Newton-Raphson method. Simulation results show that both methods deliver comparable performance in source localization. A prototype of artificial lateral line system comprising four ionic polymer-metal composite (IPMC) sensors is built, and experimental results are further presented to demonstrate the effectiveness of IPMC lateral line systems and the proposed estimation algorithms.

Artificial lateral line-based localization of a dipole source with unknown vibration amplitude and direction

“…Flow measurement with digital particle image velocimetry (DPIV) supports the validity of the model (2) for the dipolegenerated flow field [12]. We now limit our discussion to the two-dimensional x − y plane.…”

“…We assume that the presence of sensors has negligible effect on the flow distribution as characterized in (2), and that each sensor is able to provide a noisy measurement of the local flow velocity v along the x−direction. The latter consideration is motivated by that most beam-like flow sensors (e.g., the IPMC lateral line sensors [10], [12]) can only sense one component of the flow velocity. In the absence of noise, from (2), we get…”

“…In this paper we extend the work in [12] to consider the dipole localization problem where both the vibration amplitude and vibration orientation are unknown. If we consider the scenario of one fish detecting a predator using its lateral line system, the solution to the aforementioned problem would imply that the fish not only knows where the predator is, but also which way it is swimming toward.…”

“…When the vibration amplitude is varying, the problem becomes challenging, partly because a source far away but with large vibration and another source nearby but with small vibration could produce signals of similar amplitudes. Such ambiguity is addressed by our recent work [12], where a nonlinear estimation problem is formulated based on an analytical model of the dipole-generated flow field. There the source location and the vibration amplitude are treated as unknowns that we seek to identify, given the flow amplitude measurement by the sensor array.…”

A novel biomimetic sensor system for vibration source perception of autonomous underwater vehicles based on artificial lateral lines

“…Each neuron contains several cilia bundles, sealed in a gelatinous shell. Fluids may trigger the neurons to enable fish to identify near-field objects and water currents [15,16]. Coombs and Conley [17][18][19] found that the mottled sculpin can always locate vibrating objects.…”