The Phi-Bot: A Robot Controlled by a Slime Mould

Abstract

Information processing in natural systems radically differs from current information technology. This difference is particularly apparent in the area of robotics, where both the organisms and artificial devices face a similar challenge: the need to act in real time in a complex environment and to do so with computing resources severely limited by their size and power consumption. Biological systems evolved enviable computing capabilities to cope with noisy and harsh environments and to compete with rivalling life forms. Information processing in biological systems, from single-cell organisms to brains, directly utilises the physical and chemical processes of cellular and intracellular dynamics, whereas that in artificial systems is, in principle, independent of any physical implementation. The formidable gap between artificial and natural systems in terms of information processing capability [1] motivates research into biological modes of information processing. Hybrid artifacts, for example, try to overcome the theoretic and physical limits of information processing in solid-state realisations of digital von Neumann machines by exploiting the self-organisation of naturally evolved systems in engineered environments [2, 3].This chapter presents a particular unconventional computing system, the Φ-bot, whose control is based on the behaviour of the true slime mould Physarum polycephalum. The second section gives a short introduction to the information-processing capabilities of this organism. The third section describes the two generations of the Φ-bot built so far. To discuss information-theoretic aspects of this robot, it is useful to sketch the concept of bounded computability that relates generic traits of information-processing systems with specific physico-chemical constraints on the realisation of such systems in different classes of computational media. This is done in the fourth section. The concluding section gives an outlook on engineering as well as foundational issues that will be important for the future development of the Φ-bot.