Cooperative Control of Multiple Biomimetic Robotic Fish

There has been a spurt of interest in recent years in the area of group coordination and cooperative control among different research communities, involving biology, robotics, artificial intelligence, advanced control, sensor network, etc (Ögren et al., 2004; Kumar et al., 2005; Pettersen et al., 2006). As we know, fish shoals, bird flocks, etc exhibit typical aggregation behaviours, in which collective motions are employed to achieve useful tasks, e.g., avoiding predators, capturing prey, and breeding offspring. Similarly, when coordinating in unstructured or dynamic environments, it is possible that a team of relatively simple and cheap agents are capable of accomplishing complex tasks that exceed the capabilities of one single agent. In the robotic context, multi-robot systems presenting as distributed solutions have advantages such as increasing robustness to unexpected disturbances, fault-tolerance, thanks to redundancy, self-adaptation, and self-organization. Thus, applications of multi-robot systems are associated with a large group of autonomously functioning vehicles in the air, on land or sea or underwater, to jointly perform tasks such as demining operations, environmental surveillance, object transportation, search and rescue, and so forth (Kumar et al., 2002; Rabbath et al., 2007 ; Wang et al., 2007 ; Zhang et al., 2007). Rapidly growing interests in cooperation and coordination of multi-robot systems have brought a lot of real-world applications as stated above. However, most significant efforts are devoted to ground and air based cooperation issues, and cooperative studies on underwater or surface vehicle are relatively few and immature (Rabbath et al., 2007). In particular, research on a group of robotic fish has not yet been implemented. The primary objective of this chapter is to build an artifical multi-fish system mimicking cooperative mechanism of fish flock, which provides a platform to test and verify the algorithms and strategies for cooperation of multiple underwater robots. Although the topic of underwater biorobotics is not new, and there is a long history, the selfpropelled, fish-like robots were indeed created in the 1990s (Triantafyllou & Triantafyllou, 1995; Triantafillou et al., 2004; Lauder et al., 2007a). The fish-like robot, i.e., robotic fish, as a marriage of biomechanism with engineering technology, is a cross-disciplinary subject O pe n A cc es s D at ab as e w w w .in te hw eb .c om