Article

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

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

The lateral line system is an important sensory organ for fish and many aquatic amphibians, allowing them to detect predators/prey, perform rheotaxis, and coordinate schooling. There is an increasing interest in developing artificial lateral line systems, consisting of arrays of flow sensors, for underwater vehicles and robots. In this paper we consider the problem of localizing a vibrating sphere, also known as a dipole source, using an artificial lateral line system. Dipole sources emulate the movement of fish fins and are often used in the study of biological lateral lines. We assume that the location, vibration amplitude, and vibration direction of the dipole sources are all unknown. A nonlinear estimation problem is formulated based on the analytical model for dipole-generated flow field. We present two recursive algorithms for source localization, the first obtained by linearizing the original nonlinear estimation problem, and the other by solving the equations corresponding to the first-order optimality condition. Simulation results are presented to illustrate the effectiveness of the proposed approaches.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... The sensitivity of oriented piezoelectric nanofibers is almost 40 times that of piezoelectric films [10]. Therefore, we design a type of piezoelectric artificial cilia with a copper core for airflow sensing, which can satisfy the demand of pipeline ventilation monitoring system [11,12]. ...
... They coated their Si/Si 3 N 4 or aluminum nitride cantilevers with parylene for waterproof operation. Another artificial lateral line system based on ionic polymer-metal composite materials (IPMC) was used by Chen et al. and Abdulsadda et al. to localize a dipole source underwater [47] [48] [49] [50] [51]. They modeled the artificial lateral line systems by an infinite-dimensional transfer-function relating the short-circuit sensing current to the applied deformation and – later on – estimated the related flow characteristics [48] [52]. ...
Article
In the area of biomimetics, engineers use inspiration from natural systems to develop technical devices, such as sensors. One example is the lateral line system of fish. It is a mechanoreceptive system consisting of up to several thousand individual sensors called neuromasts, which enable fish to sense prey, predators, or conspecifics. So far, the small size and high sensitivity of the lateral line is unmatched by man-made sensor devices. Here, we describe an artificial lateral line system based on an optical detection principle. We developed artificial canal neuromasts using MEMS technology including thick film techniques. In this work, we describe the MEMS fabrication and characterize a sensor prototype. Our sensor consists of a silicon chip, a housing, and an electronic circuit. We demonstrate the functionality of our [Formula: see text]-biomimetic flow sensor by analyzing its response to constant water flow and flow fluctuations. Furthermore, we discuss the sensor robustness and sensitivity of our sensor and its suitability for industrial and medical applications. In sum, our sensor can be used for many tasks, e.g. for monitoring fluid flow in medical applications, for detecting leakages in tap water systems or for air and gas flow measurements. Finally, our flow sensor can even be used to improve current knowledge about the functional significance of the fish lateral line.
... Vehicle vibrations can also be desired in some cases, as they provide feedback of vehicle motion to the driver or for engine or gearbox diagnostics [1]. There are only few vibration approaches for navigation, such as [4], in which an underwater localization system is proposed based on vibration measurements with a sensor array similar to the lateral line system of a fish. A terrain classifier of a vehicle in [5] differs between sand, gravel, or clay based on vibration measurements during motion. ...
Conference Paper
Full-text available
Vehicles in motion are exposed to mechanical vibrations, resulting from various sources, such as the engine, transmission, wheels, the track and many more. Vibrations in vehicles are often undesired, but these vibrations contain navigation and vehicle information. In addition to state-of-the art techniques for the computation of spatial vehicle movements from inertial measurements, the vibration measurements can also be used explicitly for navigation with appropriate methodologies. This study focuses on vibrations in a diesel engined passenger train, measured by a vertical, translative acceleration sensor. The major vibration sources of a train in motion are identified in an analysis and characterized by speed dependency or dependency. We present procedures to separate and filter these vibrations in combination with a simple model of the vehicle. This paper presents new methods to infer vehicle speed and the wheel diameter measurements for a wheel diagnostic monitoring while in movement. Furthermore a rail vehicle localization is achieved based exclusively on vibrations measured by one accelerometer and a correlation technique. We show localization results by the location dependent vibrations and discuss an integration in a multi sensor localization approach as well as the advantages and drawbacks of vibration based navigation.
Article
Biomimetics is a promising field of research in which natural processes and structures are transferred to technical applications. The lateral line is a critical component of the fish sensory system and plays an important role in many behaviors by providing hydrodynamic information about the surrounding fluid. It is believed that the artificial lateral line flow sensors (ALLFS) are advantageous for underwater applications. This paper reviews the morphology and biophysics of the lateral line, especially theoretical models of lateral line, including biomechanical model, frequency response and time domain response of lateral line. Also, this paper reviews some efforts to mimic lateral line system in recent years. In order to capture the recent research status, this paper reviews the design and fabrication of ALLFS based on different sensing principles. Further researches to develop ALLFS and their underwater applications are also discussed in this paper.
Conference Paper
Motivated by the lateral line system of fish and amphibians, arrays of flow sensors have been proposed as a new sensing modality for underwater robots. Most existing studies on such artificial lateral lines have been focused on the localization of a vibrating sphere, also known as a dipole source. In this paper we investigate the problem of tracking a moving but non-vibrating cylindrical object and estimating its size and shape using an artificial lateral line system. Based on a nonlinear analytical model for the moving object-induced flow field, a two-stage extended Kalman filter is proposed to estimate the location, velocity, size, and shape of the object. Simulation results on tracking a cylinder with ellipsoidal cross-section are presented to illustrate the approach. On the experimental side, we demonstrate the use of an artificial lateral line prototype comprising six ionic polymer-metal composite (IPMC) flow sensors in the tracking and size estimation of a moving circular cylinder.
Article
As a flow-sensing organ, the lateral line system plays an important role in various behaviors of fish. An engineering equivalent of a biological lateral line is of great interest to the navigation and control of underwater robots and vehicles. A vibrating sphere, also known as a dipole source, can emulate the rhythmic movement of fins and body appendages, and has been widely used as a stimulus in the study of biological lateral lines. Dipole source localization has also become a benchmark problem in the development of artificial lateral lines. In this paper we present two novel iterative schemes, referred to as Gauss-Newton (GN) and Newton-Raphson (NR) algorithms, for simultaneously localizing a dipole source and estimating its vibration amplitude and orientation, based on the analytical model for a dipole-generated flow field. The performance of the GN and NR methods is first confirmed with simulation results and the Cramer-Rao bound (CRB) analysis. Experiments are further conducted on an artificial lateral line prototype, consisting of six millimeter-scale ionic polymer-metal composite sensors with intra-sensor spacing optimized with CRB analysis. Consistent with simulation results, the experimental results show that both GN and NR schemes are able to simultaneously estimate the source location, vibration amplitude and orientation with comparable precision. Specifically, the maximum localization error is less than 5% of the body length (BL) when the source is within the distance of one BL. Experimental results have also shown that the proposed schemes are superior to the beamforming method, one of the most competitive approaches reported in literature, in terms of accuracy and computational efficiency.
Article
Full-text available
Odor plumes are complex, dynamic, three-dimensional structures used by many animals to locate food, mates, home sites, etc. Yet odor itself has no directional properties. Animals use a variety of different senses to obtain directional information. Since most odor plumes are composed of dispersing odor patches and dissipating vorticity eddies, aquatic animals may localize odor sources by simultaneous analysis of chemical and hydrodynamic dispersal fields, a process referred to as eddy chemotaxis. This study examines the contributions of olfaction, mechanoreception and vision to odor source localization in a shark, the smooth dogfish Mustelus canis. Two parallel, turbulent plumes were created in an 8 m flume: squid rinse odor and seawater control. Minimally turbulent ;oozing' sources of odor and seawater control were physically separated from sources of major turbulence by placing a brick downstream from each oozing source, creating two turbulent wakes, one or the other flavored with food odor. This created four separate targets for the sharks to locate. Animals were tested under two light conditions (fluorescent and infrared) and in two sensory conditions (lateral line intact and lateral line lesioned by streptomycin). Intact animals demonstrated a preference for the odor plume over the seawater plume and for the source of odor/turbulence (the brick on the odor side) over the source of the odor alone (the odor-oozing nozzle). Plume and target preference and search time were not significantly affected by light condition. In the light, lesioning the lateral line increased search time but did not affect success rate or plume preference. However, lesioned animals no longer discriminated between sources of turbulent and oozing odor. In the dark, search time of lesioned animals further increased, and the few animals that located any of the targets did not discriminate between odor and seawater plumes, let alone targets. These results demonstrate for the first time that sharks require both olfactory and lateral line input for efficient and precise tracking of odor-flavored wakes and that visual input can improve food-finding performance when lateral line information is not available. We distinguish between rheotaxis: orientation to the large-scale flow field (olfaction, vision and superficial lateral line), eddy chemotaxis: tracking the trail of small-scale, odor-flavored turbulence (olfaction and lateral line canals), and pinpointing the source of the plume (lateral line canals and olfaction).
Article
Full-text available
An engineered artificial lateral-line system has been recently developed, consisting of a 16-element array of finely spaced MEMS hot-wire flow sensors. This represents a new class of underwater flow sensing instruments and necessitates the development of rapid, efficient, and robust signal processing algorithms. In this paper, we report on the development and implementation of a set of algorithms that assist in the localization and tracking of vibrational dipole sources underwater. Using these algorithms, accurate tracking of the trajectory of a moving dipole source has been demonstrated successfully.
Article
Full-text available
In-plane linear displacements of microelectromechanical systems are measured with subnanometer accuracy by observing the periodic micropatterns with a charge-coupled device camera attached to an optical microscope. The translation of the microstructure is retrieved from the video by phase-shift computation using discrete Fourier transform analysis. This approach is validated through measurements on silicon devices featuring steep-sided periodic microstructures. The results are consistent with the electrical readout of a bulk micromachined capacitive sensor, demonstrating the suitability of this technique for both calibration and sensing. Using a vibration isolation table, a standard deviation of σ = 0.13 nm could be achieved, enabling a measurement resolution of 0.5 nm (4σ) and a subpixel resolution better than 1/100 pixel. [2010-0170]
Article
Full-text available
Hydrodynamic imaging using the lateral line plays a critical role in fish behavior. To engineer such a biologically inspired sensing system, we developed an artificial lateral line using MEMS (microelectromechanical system) technology and explored its localization capability. Arrays of biomimetic neuromasts constituted an artificial lateral line wrapped around a cylinder. A beamforming algorithm further enabled the artificial lateral line to image real-world hydrodynamic events in a 3D domain. We demonstrate that the artificial lateral line system can accurately localize an artificial dipole source and a natural tail-flicking crayfish under various conditions. The artificial lateral line provides a new sense to man-made underwater vehicles and marine robots so that they can sense like fish.
Article
Full-text available
In a previous study we showed that nocturnal piscivorous catfish track the wake left by a swimming prey fish to locate it, following past locations to detect the present location of the prey. In a wake there are hydrodynamic as well as chemical signatures that both contain information on location and suitability of the prey. In order to determine how these two wake stimuli are utilised in prey tracking, we conducted experiments in catfish in which either the lateral line or the external gustation was ablated. We found that a functional lateral line is indispensable for following the wake of swimming prey. The frequency of attack and capture was greatly diminished and the attacks that did occur were considerably delayed when the lateral line was ablated. In contrast, catfish with ablated external taste still followed the wakes of their prey prior to attacking, albeit their attacks were delayed. The external taste sense, which was reported earlier to be necessary for finding stationary (dead) food, seems to play a minor role in the localisation of moving prey. Our finding suggests that an important function of the lateral line is to mediate wake-tracking in predatory fish.
Chapter
This review covers four areas of research that have fruitfully contributed to our understanding of lateral line function within the past 10 years. One striking aspect of the lateral line system is its tremendous diversity. Recent findings, however, indicate a functional constancy that may be maintained by relatively subtle morphological features. Other morphological variations have been shown to enhance sensitivity at particular frequency bandwidths. A second area of research has focused on hydrodynamic imaging and the peripheral patterns of receptor excitation that might encode stimulus features such as amplitude, distance, location, and direction of motion. A detailed model is described and provides several predictions for the types of information passed from the periphery to the central nervous system (CNS).The third topic covered is the mechanisms that enhance signal detection in noisy backgrounds. It is becoming clear that canals act as biomechanical filters to improve signal-to-noise ratios in the presence of lowfrequency noises such as uniform, ambient water motions. Two central mechanisms, efferent modulation of receptor excitation and a central dynamic filter mechanism, have been shown to reduce reafference due to self-generated noise and may enhance signal detection in general. The second central mechanism is postulated to be similar to the anti-hebbian learning mechanism that has been well documented within the related electrosensory system. Finally, this review covers the recently documented roles of the lateral line system in natural behaviors, including courtship and prey capture. Some of these recent studies have led to the exciting conclusion that the lateral line may be composed of two distinct information channels, one served by canal and the other by superficial neuromasts, and that each may be dedicated to different behavioral tasks.
Article
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.
Article
A gel-supported lipid bilayer formed at the base of an artificial hair is used as the transduction element in a membrane-based artificial haircell sensor inspired by the structure and function of mammalian outer hair cells. This paper describes the initial fabrication and characterization of a bioderived, soft-material alternative to previous artificial haircells that used the transduction properties of synthetic materials for flow and touch sensing. Under an applied air flow, the artificial hair structure vibrates, triggering a picoamp-level electrical current across the bilayer. Experimental analysis of this mechanoelectrical transduction process supports the hypothesis that the oscillating current is produced by a time-varying change in the capacitance of the membrane caused by the vibration of the hair. Specifically, frequency analysis of both the motion of the hair and the measured current show that both phenomena occur at similar frequencies, which suggests that changes in capacitance occur as a result of membrane bending during excitation.
Article
The information processing capabilities of the lateral line system and its potential utility in surveying foreign environments and providing sensory guidance to autonomous vehicles in dark or highly turbulent conditions is reviewed. The lateral line is a spatially-distributed system of directionally-sensitive sensors that respond to low-frequency water motions created by nearby moving sources, the animal's own movements, the ambient motions of the surrounding water, and distortions in ambient or self-generated motions caused by the presence of stationary objects. While lateral line sensors on the skin surface appear to serve behaviors dependent on large-scale stimuli, such as upstream orientation to bulk water flow, other sensors enclosed in fluid-filled canals appear to subserve behaviors requiring information about fine spatial details, such as prey localization. Stimulation patterns along sensor arrays provide rich information about the location, distance and direction of moving sources. The lateral line system has also evolved several different mechanisms—static biomechanical filters at the periphery and dynamic neural filters in the central nervous system—for enhancing signal-to-noise ratios in different behavioral contexts, ranging from unexpected events of importance (e.g., an approaching predator or prey) to expected events of little relevance (e.g., the animal's own repeated and regular breathing movements).
Conference Paper
Fish and aquatic amphibians use the lateral line system, consisting of arrays of hair-like 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 polymer-metal 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 was validated in localization of underwater motion sources, including both a vibrating sphere (a dipole source) and a flapping foil. In particular, as a proof of concept, a prototype with Body Length (BL) of 8 cm, comprising five millimeter-scale IPMC sensors, was constructed and tested. Experimental results showed that the IPMC-based lateral line could localize the sources from 4-5 BLs away, with a localization error comparable to source placement resolution at the source sensor separation of 1 BL. In addition to the ease of fabrication, these results established the competitiveness of the proposed approach, in terms of both localization range and accuracy, against the state of the art in artificial lateral lines.
Article
Vision is not required in order for fish to school. Five individual saithe, Pollachius virens, were able to join schools of 25 normal saithe swimming in an annular tank, while blinded with opaque eye covers. Test fish maintained position within the school indefinitely and responded to short-term movements of individuals within the school, although quantitative differences in reaction time and schooling behavior were noted. Five fish with lateral lines cut at the opercula were unable to school when wearing opaque eye covers. Although it is unlikely that blind saithe could school in the wild, the constraints of the apparatus permitted a demonstration of a role of the lateral line organ in schooling.
Article
Nearly all underwater vehicles and surface ships today use sonar and vision for imaging and navigation. However, sonar and vision systems face various limitations, e.g., sonar blind zones, dark or murky environments, etc. Evolved over millions of years, fish use the lateral line, a distributed linear array of flow sensing organs, for underwater hydrodynamic imaging and information extraction. We demonstrate here a proof-of-concept artificial lateral line system. It enables a distant touch hydrodynamic imaging capability to critically augment sonar and vision systems. We show that the artificial lateral line can successfully perform dipole source localization and hydrodynamic wake detection. The development of the artificial lateral line is aimed at fundamentally enhancing human ability to detect, navigate, and survive in the underwater environment. • dipole localization • hot wire anemometer • micromachining • wake detection • neuromast