CONTROLLER-DESIGN FOR EXTENDING PERIODIC DYNAMICS OF A CHAOTIC CO2-LASER

The paper considers a single-mode CO2 laser that exhibits a cascade of period doubling bifurcations leading to chaos when it is driven by a sinusoidal signal of increasing amplitude. The requirement of a proper working of the laser, for relatively large amplitude of the forcing s ignal, naturally leads to the control problem of stabilizing periodic motions. Two control schemes are designed: the first one is based on d elayed control signals for stabilizing unstable periodic orbits embedd ed in the chaotic attractor, while the second one relies on the cancel lation of subharmonic components of the chaotic motions. Simulations a nd experimental tests are presented to show the control performance. ( C) 1997 Elsevier Science B.V.