Functional Freeform Fabrication for Physical Artificial Life

Abstract

Solid freeform fabrication (SFF) allows 3D-printing of arbitrarily shaped structures, directly from computer-aided design (CAD) data. SFF has traditionally focused on printing passive mechanical parts. Advances in this technology and developments in materials science make it feasible to begin the development of a single, compact, robotic SFF system - including a small set of materials which can produce complete, active, functional electromechanical devices - mobile robots, for instance. We are advancing steadily toward this goal, and successes thus far have included the freeform fabrication of zinc-air batteries, conductive wiring, flexure joints, and combinations of these with thermoplastic structures. Several essential functionalities - actuation, sensing, and control electronics - still remain to be realized before complete electromechanical systems can be produced via SFF. Conducting polymers (CP) are a class of materials which can be used to produce all of these. Several SFF-compatible CP processing methods have been identified, and actuators produced via one of these have been demonstrated. When coupled in a closed-loop with an evolutionary design system, the ability to produce robots entirely via SFF becomes a bridge between the physical and the simulated, giving artificial evolution a complete physical substrate of enormous richness to explore with little or no human involvement.