Focused Modularity : Rapid Iteration of Design and Fabrication of a Meter-Scale Hexapedal Robot

Robots are faced with increasingly complex, hard to simulate environments. Multilegged robots exhibit dynamics that are often difficult to model well. Their development thus depends on experimental verification. Here we propose “focused modularity” – an approach combining benefits of both modular robotics and more traditional rapid fabrication. We made robot mechanisms by laser cutting low-cost foam board, while the complexity of motor control and electronics is focused in a small number of servomotor modules. This dramatically reduced the cost and time of design iteration, and allowed incremental improvements to make up for deficits in material strength and manufacturing tolerance. We present meter-scale hexapods whose chassis and drive train were manufactured for under 20 USD and under four hours of skilled labor. To date we have produced over 40 revisions of the design, including 25 iterations of drive mechanism design and 7 full robot prototypes built. This represents a substantially more thorough exploration of the design space than could be possible using conventional development approaches. We suggest a library of suitable robot designs to be developed, permitting a robot to be built on the fly with functionality for a particular task as the situation demands.