Controlling chaos with simple limiters

New experimental results demonstrate that chaos control can be accomplished using controllers that are very simple relative to the system being contro lled. Chaotic dynamics in a driven pendulum and a double scroll circuit are controlled using an adjustable, passive limiter - a weight for the pendulu m and a diode for the circuit. For both experiments, multiple unstable peri odic orbits are selectively controlled using minimal perturbations. These p hysical examples suggest that chaos control can be practically applied to a much wider array of important problems than initially thought possible.