Multi-Purpose Artificial Muscle and Sensor Array for Untethered Soft Robots

The Objective of this proposal is to produce a “soft robotic tissue” multifunctional composite and demonstrate its potential application for space robotics. The composite is a 1-5 mm thick elastic sheet that can be stretched to conform to any host structure. Since it does not contain any rigid, brittle, or inextensible materials, the composite remains functional under extreme elastic deformations of up to 200% strain. It contains elastically deformable circuits, sensing elements, and transducers that can support electronic functionality in wearable, inflatable, and collapsible systems. In the case of bio-inspired soft robots, the proposed material can function as “artificial” skin, nervous tissue, and muscle. Lastly, the integrated electronics are engineered to interface with surface-mounted chips for computing, power, and wireless integration. Robotics implementation represents a secondary objective that was pursued in Y2/Y3. This includes wearable circuits for tactile sensing and environmental mapping and a soft robot quadruped with mechanically resilient circuitry. Such implementations highlight the versatility and robust properties of the proposed multifunctional composite. 
Building on research accomplishments over the duration of this ECF, we achieved the following:
•Finalized design and fabrication of wireless, skin-mountable patches for multi-modal sensing (pressure, proximity, pulse oximetry, temperature).
•Completed study of wireless patches for tactile sensing and environmental mapping data collected with R2. This work was performed at JSC in collaboration with Jonathan Rogers (ER4).
•Development and characterization of an autonomously self-healing conductive elastomer. The elastomer is composed of silicone rubber embedded with a suspension of liquid metal (LM) microdroplets.
•Integration of self-healing conductive elastomer and thermal actuators to create a soft robot quadruped. The conductive elastomer is patterned as a soft circuit that connects the thermal actuators to the on-board electronics on power supply. The quadruped is capable of continuous walking even as the circuit is mechanical damaged.