Soft Actuators and Robots that Are Resistant to Mechanical Damage

• Published in: Advanced functional materials Vol. 24; no. 20; pp. 3003 - 3010
• Main Authors: Martinez, Ramses V., Glavan, Ana C., Keplinger, Christoph, Oyetibo, Alexis I., Whitesides, George M.
• Format: Journal Article
• Language: English
• Published: Blackwell Publishing Ltd 01-05-2014
• Subjects: Actuators; Automation; composites; Damage; Elastomers; impact resistance; Manufacturing engineering; Networks; pneumatic actuators; Pneumatics; Robots; soft machines; soft robotics
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201303676

This paper characterizes the ability of soft pneumatic actuators and robots to resist mechanical insults that would irreversibly damage or destroy hard robotic systems—systems fabricated in metals and structural polymers, and actuated mechanically—of comparable sizes. The pneumatic networks that actuate these soft machines are formed by bonding two layers of elastomeric or polymeric materials that have different moduli on application of strain by pneumatic inflation; this difference in strain between an extensible top layer and an inextensible, strain‐limiting, bottom layer causes the pneumatic network to expand anisotropically. While all the soft machines described here are, to some extent, more resistant to damage by compressive forces, blunt impacts, and severe bending than most corresponding hard systems, the composition of the strain‐limiting layers confers on them very different tensile and compressive strengths.
Soft pneumatic actuators and robots based on composites consisting of elastomers and embedded flexible reinforcing sheets are significantly more resistant to blunt impacts, tensile forces, and severe bending than hard robotic systems of similar size and weight. The range of physical damage that soft robots and actuators can withstand without suffering changes in mechanical performance is quantified.