Particle swarm-based olfactory guided search

This article presents a new algorithm for searching odour sources across large search spaces with groups of mobile robots. The proposed algorithm is inspired in the particle swarm optimization (PSO) method. In this method, the search space is sampled by dynamic particles that use their knowledge about the previous sampled space and share this knowledge with other neighbour searching particles allowing the emergence of efficient local searching behaviours. In this case, chemical searching cues about the potential existence of upwind odour sources are exchanged. By default, the agents tend to avoid each other, leading to the emergence of exploration behaviours when no chemical cue exists in the neighbourhood. This behaviour improves the global searching performance. The article explains the relevance of searching odour sources with autonomous agents and identifies the main difficulties for solving this problem. A major difficulty is related with the chaotic nature of the odour transport in the atmosphere due to turbulent phenomena. The characteristics of this problem are described in detail and a simulation framework for testing and analysing different odour searching algorithms was constructed. The proposed PSO-based searching algorithm and modified versions of gradient-based searching and biased random walk-based searching strategies were tested in different environmental conditions and the results, showing the effectiveness of the proposed strategy, were analysed and discussed. Lino Marques is an auxiliary professor in the Department of Electrical Engineering, University of Coimbra, and he is a researcher in the Institute for Systems and Robotics (ISR-UC). He received his Licenciatura, MSc. and Ph.D. degrees in Electrical Engineering from the University of Coimbra, Portugal. His main research interests include embedded systems, mechatronics, robotics for risky environments, optical range sensors, artificial olfaction systems and mobile robot olfaction. Urbano Nunes is an associate professor of the University of Coimbra and a researcher of the Institute for Systems and Robotics (ISR-UC), where he has been involved in research and teaching since 1983. He received his Licenciatura and Ph.D. degrees in Electrical Engineering from the University of Coimbra, Portugal, in 1983 and 1995, respectively. He is the coordinator of the Mechatronics Laboratory of ISR-UC, and had been responsible for several funded projects in the areas of mobile robotics and intelligent vehicles. His research interests include mobile robotics, intelligent vehicles, and mechatronics. Professor Urbano Nunes serves on the Editorial Board of the Journal on Machine Intelligence and Robotic Control, and currently he is co-chair of the IEEE RAS TC on Intelligent Transportation Systems. Currently he is the Program Chair of the IEEE ITSC2006. He has served as General Co-Chair of ICAR 2003 and as member of several program committees of international conferences. Aníbal T. De Almeida graduated in Electrical Engineering, University of Porto, 1972, and received a Ph.D. in Electrical Engineering, from Imperial College, University of London, 1977. Currently he is a Professor in the Department of Electrical Engineering, University of Coimbra, and he is the Director of the Institute of Systems and Robotics since 1993. Professor De Almeida is a consultant of the European Commission Framework Programmes. He is the co-author of five books and more than one hundred papers in international journals, meetings and conferences. He has coordinated several European and national research projects.