Chemical plumes can arise from accidental spills, or deliberate terrorist attacks. The research described in this proposal extends the state-of-the-art by using robust teams of mobile ground-based sensing robots for the task of chemical plume tracing. The two leading methods for chemical plume tracing are chemotaxis and anemotaxis. The former follows the gradient of chemical concentration. It is misled by pockets of high chemical density that are not sources. Anemotaxis moves upwind whenever an above-threshold level of chemical is detected. It is misled by wind sources that are not chemical sources. The PI has developed an alternative algorithm, called Fluxotaxis, based on fundamental principles of fluid dynamics, that overcomes the weaknesses of the prior approaches. Fluxotaxis is tailored to be computationally efficient for a set of microprocessors running in parallel. Each robot is a grid point in a computational Fluid dynamics mesh/lattice. The robots act as a distributed sensing network, performing flow analyses and making navigational decisions based on these analyses. The main thrust of the proposed effort is to perform experimental investigation on actual robots and real chemical plumes. The project would have an impact at the national and local levels, especially for U.S. homeland defense and U.S. counter-terrorism missions with airborne/aquatic plumes of biological or radiological hazards.
