Rapid energy release in inflatable soft actuators through reversible bond breaking

Abstract

Inflatable actuators are regularly used to induce large complex deformations in soft robotic systems. Their actuation speed is typically low, as it takes time for fluids to be pushed through narrow pressure supply tubes. To overcome this limitation, we take inspiration from nature and create actuators that can suddenly release build up elastic energy, by means of breaking a physical bond. Where in nature these ruptures are irreversible, here we use the reversible adhesion of a suction cup to accomplish the same behavior. First, we show that the released elastic energy originates from an adiabatic transition from the constrained to the free inflation curve of the actuator. Next, we numerically analyse this process and give design considerations for maximizing energy release. Lastly, we build a prototype actuator that displays this type of energy release and demonstrate that it can be used for jumping.