The Ancient Greek term κῦμα (pronounced Kima) means wave, the physical movement on the surface of a liquid layer. In physics, a wave describes dynamic disturbances of a physical quantity around a position of equilibrium. By controlling the vertical position of each of the twenty-five spheres, κῦμα produces a discrete 3D levitating choreography. Randomly activated fans interact with the spheres, disturbing their movements by blowing from above: the choreography patterns are broken, becoming unstable or even chaotic. A control loop feedback mechanism counteracts this tendency towards chaos; its efficiency varies over time, highlighting the impact of its action. This artwork allows to introduce and explain basics of control system design and automation science which deal with the modelling, analysis, identification and control of dynamic systems. It focuses on controlling a system to comply with precise requirements such as execution time, precision and stability. Thanks to the mathematical equations defining the physical laws of the system, κῦμα controls itself through the real-time processing of multiple signals from sensors and motors. The analogue signals of the physical system are used as raw data to generate digital visuals reinterpreting the movements, disturbances and deviations of the spheres and airflows.
