Metachronal waves in cellular automata: Cilia-like manipulation in actuator arrays

Paramecium is covered by cilia. It uses the cilia to swim and transport food particles to its mouth. The cilia are synchronised into a collective action by propagating membrane potential and mechanical properties of their underlying membrane and the liquid phase environment. The cilia inspired us to design and manufacture a hardware prototype of a massively parallel actuator array, emulated membrane potentials via a discrete excitable medium controller and mechanical properties based on vibrating motors. The discrete excitable medium is a two-dimensional array of finite automata, where each automaton, or a cell, updates its state depending on states of its closest neighbours. A local interaction between the automata lead to emergence of propagating patterns, waves and gliders. The excitable medium is interfaced with an array of actuators. Patterns travelling on an automaton array manifest patterns of actuation travelling along the array of actuators. In computer models and laboratory experiments with hardware prototypes we imitate transportation of food towards mouth pore of the Paramecium. The hardware actuator arrays proposed could in future replace simple manipulators in demanding micro-scale application.