Multilayer Extending Actuator for Soft Robotic Applications

The benefits of soft robotic actuators over hard robots have been recognized and are increasingly used in various fields. Soft actuators capable of yielding a high force output often need a tradeoff between its size, extensibility, and weight. This paper presents a novel multilayer extending actuator (MEA) that is thin and light but also capable of high extension and high force output. When actuated, the MEA has visible layers of alternate inelastic and elastic elastomer layer. The MEA is fabricated using silicone elastomers and operated by pneumatic pressure. The inelastic layers help increase the actuator's durability and extension by inhibiting the elastic layers to expand radially. This makes the MEA stronger, capable of a tip force more than 400 times its weight, and an extension of 5 times its body depth. The design and fabrication of the system are described, and a theoretical model is introduced for predicting the extension and force output. Finally, a simple demonstration of its modularity and application in operating a robotic arm is presented. The MEA can be conceptualized as a spring system as it helps to increase the total extension when connected in series while helping to increase the total force when connected in parallel instead.