KDI: Coordinated Motion of Natural and Man-Made Groups

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Be it a school of fish swimming gracefully through the water, a herd of deer running through a meadow, a flock of birds flying across the horizon, or a swarm of bees circling about a hive one cannot help but wonder how these and other similar natural groupings, coordinate themselves and move so flawlessly, often without an apparent leader or any form of centralized control. What kinds of signaling must they use? What role if any, do currents, vortices, or other local environmental disturbances play in this process? Are there universal principles of coordinated group motion and if so what might they be? How might they be used to design a school of autonomous submerged vehicles, or a group of ground-based or airborne mobile robots to collectively accomplish a useful task in a coordinated manner? In broad terms, these are the questions to which this research will be addressed.More specifically, we propose to mount a cross-disciplinary assault on the joint problems of understanding how fish schools coordinate their collective motion and how schools of autonomous submerged vehicles might be designed to move in a coordinated manner. We propose to address these problems experimentally, theoretically and by means of computer simulation. At the theoretical level, our aims will be to develop models, which are biologically plausible, and, in addition, operating strategies will enable coordinated group motion of engineered systems. Our ultimate goal is not to derive analytical models nor to develop computer simulations, which are visually satisfactory, but rather to discover the underlying concepts upon which the coordination of group motion might depend. Thus, for example we would hope to develop concepts which, on the one hand might help to explain how fish maintain their spacing and, on the other might serve as guidelines for the design of groupings of man-made autonomous vehicles of all types.The experimental thrust of this research will proceed in two distinct but parallel directions. With the objective of gathering the world's first data-base documenting the long-term, three-dimensional motions of individual fish within a large school, we will take timed sequences of stereo video images of actual fish schools living in a large {1000 gallon or more} tank. We will image the responses of schools to various stimuli and under various conditions. Using advanced image/vision processing techniques, we will transform this data into a form suitable for verifying the validity of proposed behavioral and analytical schooling models. This database together with full documentation will be made available to the science and engineering communities via the World Wide Web.With the objective of trying out candidate group coordination strategies in a reasonably realistic setting, we will develop an experimental test facility consisting of a school of approximately a dozen, identical miniature underwater vehicles. These experiments are expected to be useful for both the biological and the engineering perspectives; we will be able to test robotic versions of hypothesized biology models not possible in a fish tank. Experiments with this man-made school will be carried out in an Olympic-sized swimming pool, which is available at Princeton University. Our first goal will be to instrument these vehicles so that they can function autonomously, without remote control. We will then experiment with a variety of maneuvers including group formation, cruising, bifurcating, avoiding obstacles, and changing group shapes. We will implement various biologically inspired goal-seeking strategies such as foraging as well as gradient climbing tasks relevant both to biology and to numerous engineering applications.The research we are proposing will be carried out by a cross-disciplinary team consisting of experimental and theoretical biologists together with experts in computer vision, control systems and robotics. It is our view that by means of this multi-pronged assault consisting of theoretical analysis, computer simulation, and experimentation with both natural and man-made groups, we can attain an understanding of the underlying mechanisms governing the coordinated motion of natural and man-made groups.