Muscle-inspired flexible mechanical logic architecture for miniature robotics

Miniature robots (~10nm-100micron) that morph in response to external stimuli such as light or chemicals in their local environment have the potential to perform non-invasive treatments inside the body, clean up oil spills, or be embedded in textiles to intelligently tune fabric properties. Such robots can now be realized due to advancements in materials offering, e.g., stimuli-responsive polymers that actuate like artificial muscles. For maximum control using global triggers (stimuli), computation ability needs to be incorporated within these robots. The challenge is to design an architecture that is compact, material agnostic, stable under stochastic forces, and employs stimuli-responsive materials. Here we demonstrate such an architecture, which computes combinatorial logic via mechanical gates that use linear actuation (expansion and contraction). Additionally, the logic circuitry is physically flexible. We mathematically analyze gate geometry and discuss tuning it for the given signal requirements. We validate the design at colloidal scales using Brownian dynamics simulations. Finally, we simulate a complete robot that folds into Tetris shapes.