Computational Design and Fabrication of Modular Robots with Untethered Control

Natural organisms use distributed actuation via their musculoskeletal systems to adapt their gait for traversing diverse terrains or to morph their bodies to perform varied tasks. A longstanding challenge in the field of robotics is to mimic this extensive adaptability and range of motion. This has led humans to develop various soft robotic systems that emulate natural organisms. However, such systems are generally optimized for a single functionality, lack the ability to change form or function on demand, or are often tethered to bulky control systems. To address these challenges, we present our framework for designing and controlling robots that mimic nature's blueprint by utilizing distributed actuation. We propose a novel building block that combines 3D-printed bones with liquid crystal elastomer (LCE) muscles as lightweight actuators and enables the modular assembly of musculoskeletal robots. We developed LCE rods that contract in response to infrared radiation, thereby achieving local and untethered control over the distributed network of bones, which in turn results in global deformation of the robot. Furthermore, to capitalize on the extensive design space, we develop two computational tools: one to optimize the robot's skeletal graph, enabling multiple target deformations, and another to co-optimize the skeletal designs and control gaits to achieve target locomotion. We validate our system by building several robots that show complex shape morphing, varying control schemes, and adaptability to their environment. Our system integrates advances in modular material building, untethered and distributed control, and computational design to introduce a new generation of robots that brings us closer to the capabilities of living organisms.