Crayfish Robot That Generates Flow Field to Enhance Chemical Reception

Abstract

This paper describes a wheeled underwater robot developed for locating chemical sources autonomously under stagnant flow conditions. In still water, the released chemical stays in the immediate vicinity of the source location. The search for chemical sources under such conditions is extremely laborious since the presence of a chemical source cannot be detected from a distant place. The chemical sensors on the robot show no response unless a chemical substance released from the source arrives at the sensors. Crayfish in search of food are known to actively generate water currents by waving their small appendages with a fan-like shape. It is considered that the generated water currents help their olfactory search. The smell of food is carried to their olfactory organs from the surroundings by the generated flow, and then is perceived. The robot presented in this paper employs arms mimicking the maxillipeds of a crayfish to generate water currents and to draw chemicals to its sensors. By waving the arms vertically, a three-dimensional flow field is generated and water samples are drawn from a wide angular range. The direction of a chemical source can be determined by comparing the responses of four laterally aligned electrochemical sensors. Experimental results show that the flow field generated by the maxilliped arms is more effective in collecting chemical samples onto the sensors than that generated by a pump. The robot equipped with the maxilliped arms can detect the presence of a chemical source even if the source is placed off the trajectory of the robot.

Using Chemical Sensors as “Noses” for Mobile Robots

“…Submersible wheeled robots [42][43][44][45] and swimming robots [46,47] were used to find underwater chemical sources. Flying robots were developed to try three-dimensional gas source localization and gas distribution mapping [12,48,49].…”

“…Crayfish are known to generate directed water currents by waving their small appendages with a fanlike shape [74]. A wheeled submersible robot equipped with electrochemical sensors and fanning arms was developed to mimic the olfactory search behavior of crayfish [45]. Water currents generated by using the fanning arms were used to draw water samples from the surroundings to the chemical sensors on the robot.…”

Compact Surface Plasmon Resonance Sensor for Underwater Chemical Sensing Robot

“…We chose crayfish as a model animal and have been investigating their behavioral mechanism to develop chemical source localization robots. The crayfish robot developed in our group is equipped with active flow generators to enhance the chemical reception and to facilitate the source localization under stagnant flow conditions [4].…”

Environmental monitoring using autonomous vehicles: a survey of recent searching techniques

“…The robotic crayfish with two arms that mimics the maxillipeds of a crayfish [20], swimming eel-like robot that uses body undulations for maneuvering [21], and robotic fishes that use caudal swimming to provide forward thrust [22,23] are few examples of bio-inspired robotic platforms. In [20], the authors used the robotic crayfish for chemical source localization purposes in a small controlled aquatic environment. The robot uses its wheels to move at the bottom of a water reservoir and uses its two arms to improve the detection of chemical substances in water.…”

“…Notice that experimental results such as odor tracing in a wind tunnel [10 • ], [11,12,13,14], [15 • ], underground gas leakage tracing in a and pool [7], and source tracing in a controlled water reservoir [20,23], were all carried out in controlled environments. On the other Figure 1 (adapted from [29]): Example of chemotaxis of three agents using a leader-follower approach.…”