Shape-Changing Materials Using Variable Stiffness and Distributed Control

We describe a robotic material that tightly integrates sensing, actuation, computation, and communication to perform autonomous shape change. The composite consists of multiple cells, each with the ability to control their local stiffness (by Joule heating of a thermoplastic) and communicate with their local neighbors. We also present a distributed algorithm for calculating the inverse kinematic solution of the resulting N-body system by iteratively solving a series of problems with reduced kinematics. We describe material design choices, mechanism design, algorithm, and manufacturing, emphasizing the interdisciplinary codesign problem that robotic materials pose, and demonstrate the results from a series of shape-changing experiments.