Chaos on Technical Control Systems

Erik Mosekilde
Center for Chaos and Turbulence Studies, Department of Physics, The Technical University of Denmark 2800 Lyngby, Denmark
Technical control systems are often extremely complicated. At first one might think that such systems would always be stable, and that chaos could not occur. This would be in striking contrast, then, to the manner in which biological control systems work, and one might imagine that a different, more "organic" and perhaps much more efficient technology could be developed where the various parts of a system interacted more closely, performed different functions at different times, and to a certain degree could substitute for one another. The seminar first discusses a biological example: the pulsatile secretion of insulin in man. It is shown how this secretion can entrain with external variations in the supply of glucose, and how a pulsatile secretion can be more effective in eliciting glucose utilization in the cells than a constant secretion at the same average rate. The seminar continues to discuss frequency locking, chaos and other highly nonlinear phenomena in a variety of technical control systems including thermostatically controlled radiators, refrigeration systems, and thrust vectoral fighter planes.