Download Artificial Lateral Line Technology

Artificial Lateral Line Technology
by Martha - Friday, August 24, 2012, 01:15 AM
Lateral Line in Fish Inspires Artificial Sensors in Underwater Vessels
Fish are able to orient themselves in currents, identify “home” territory, and identify and locate
predators or prey underwater in even very low visibility due in large part to the lateral line of sensors
that runs down the center of their bodies. This lateral line is found in all fish species from the smallest
gobies to the largest whale sharks. The line is composed of millions of hair-like sensors associated with
nerves. The hairs, stimulated by movement in the water, trigger nerves that send complex signals about
the environment to the fish.
More specifically, the lateral line is visible along the side of most fish. Rather than being a physical or
solid line, the structure is composed of millions of closely placed hair assemblies. Each individual sensor
hair is surrounded by a corresponding set of hairs that create a sort of bristle assembly within the pore
structure. The action of the water on each of the primary and corresponding hairs at a given site
provides information about movement in the water. Water moving from different directions will interact
with the corresponding hairs differently, providing evidence to that site of the direction of movement.
As the brain assembles information from the millions of cells along the lateral line, clear information can
be developed about what is in the water, where it is, and what movement it makes (Webb,
Montgomery, and Modgens, 2008; Yamanaka, Masanori, Fukuda, & Sasaki, 2010).. Fish cannot be said to
“make sense” of this data but rather their brains are able to sort and monitor the influx of information
to analyze the environment around them. This occurs on a level of speed and sensitivity comparable to
that by which humans sort the mountains of information they have incoming such as the surfaces on
which they sit, the clothing that touches their body, background noise and danger signals to identify
information important for the survival.
The lateral line is so sensitive that it is capable of discerning movement in the immediate area from that
in the background or distance (Klein & Bleckmann, 2012). For this reason, it is impossible to sneak up on
a fish from behind despite the fact that their eyes are poorly located for a prey species. Likewise, the
lateral line enables fish to maintain school structures and detect interlopers to their school structure, in
most cases (Partridge, & Pitcher, 1980). There are some fish that are able to masquerade as school
members or shadow other fish species but the evolution of these behaviors is quite elaborate and
advanced.
Borrowing from this ability, researchers have been working to develop artificial lateral line sensor
capability for underwater robots. Researchers at the Technical University in Munich (TUM) Germany
have developed mechanical sensors inspired by the hair/nerve component of fish lateral lines and
implanted that technology in the robot, Snookie (no relation to the New Jersey pseudo-celebrity)
(Franosch, Sosnowski, Chami, Kuhnlenz, Hirchet, & van Hememen, 2010). The artificial sensors are
thermistors – ceramic or polymer sensors that react to specific variances in temperature to open or
close circuits, converting temperature signals into electrical impulses. These impulses are managed or
monitored by remote or tethered computers that operate on the information.
A single TUM project thermistor is only 0.36mm. Rows of these thermistors can be arranged along the
sides of Underwater Remote Operated Vehicles (UROV) to provide more sophisticated information
about UROV position, orientation, and environment than was previously possible.
Someday, nanotechnology may make it possible to create thermistors at a much smaller scale, such as
that shown below. Applications for such nanothermistors is limitless.
Photo courtesy of http://www.gizmag.com/researchers-create-lateral-linesensors/14141/picture/110314/
References
 Akanyeti, O.,, Fiazza, C., & Fiorini, P. (2010). Attentional mechanisms for lateral line sensing through
spectral analysis. Lecture Notes in Computer Science, 6226(From Animals to Animats, 11)252-262.
 Coombs, S. (2001). Smart skins: Information processing by lateral line flow sensors. Autonomous
Robots, 11(3) 255-261.
 Franosch, J.M.P., Sosnowski, S., Chami, N.K., Kuhnlenz, K., Hirchet, S., & van Hememen, J. L. (2010).
Biomimetic lateral-line system for underwater vehicles. Retrieved from
http://www.t35.ph.tum.de/addons/publications/Franosch-2010.pdf
 Klein, A.T., & Bleckmann, H. (2012). Lateral line canal morphology and noise reduction. The Effect of
Noise on Aquatic Life: Advances in Experimental Medicine and Biology, 730 (Part II) 121-123. DOI:
10.1007/978-1-4419-7311-5_27.
 Montgomery, J.C., Coombs, S., & Baker, C.F. (2001). The mechanosensory lateral line system of the
hypogean forms of. Environmental Biology of Fishes, 62(1-3) 87-96.
 Partridge, B.L., & Pitcher, T.J. (1980). The sensory basis of fish schools: Relative roles of lateral lines
and vision. Journal of comparative Physiology A: Neurothology, Sensory, Neural, and Behavioral
Physiology, 135(4)315-325.
 Qualtieri, A.; Rizzi, F.; Todaro, M.T.; Passaseo, A.; Cingolani, R.; De Vittorio, M. (2011). Stress-driven
AlN cantilever-based flow sensor for fish lateral line system. Microelectronic Engineering, 88(8)23762378. DOI: 10.1016/j.mee.2011.02.091.
 Webb, J.F., Montgomery, J.C., and Mogdans, J. (2008). Bioaccustics and the lateral line in fish. In,
Webb, J.F., Fey, R.R., and Popper, A.N. (Eds.). Springer Handbook of Auditory Research, 1, 32, (Fish
Bioacoustics)145-182.
 Yang, Y., Chen, J., Engel, J., Pandya, S., Chen, N., Tucker, C., Coombs, S., Jones, D.L., & Chang, L.
(2006). Distant touch hydrodynamic imaging with an artificial lateral line. Proceedings of the
National Academy of Sciences,103(50)18891-18895. DOI:10.1073/pnas.0609274103.