Collective Actuation

Modular robot designers confront inherent tradeoffs between size and power. Smaller, more numerous modules increase the adaptability of a given volume or mass of robot, allowing the aggregate robot to take on a wider variety of configurations, but do so at a cost of reducing the power and complexity budget of each module. Fewer, larger modules can incorporate more powerful actuators and stronger hinges, but at a cost of overspecializing the resulting robot in favor of corresponding uses. In this paper we describe a technique for coordinating the efforts of many tiny modules to achieve forces and movements larger than those possible for individual modules. In a broad sense, our work aims to make actuator capacity and range at least partly fungible by algorithm design and ensemble topology, rather than being immutable properties of a particular module design. An important aspect of this technique is its ability to bend complex and large-scale structures and to realize the equivalent of large-scale joints. By enabling scalable joints, and the “muscles” that could actuate larger structures, our work makes it more likely that modular robot ensembles can successfully be scaled up in number and down in size. KEY WORDS—cellular and modular robotics