Thermoelastic Strain-limiting Layers to Actively-control Soft Actuator Trajectories

Soft pneumatic actuators (SPAs) are made from strategically combined several soft materials with different stiffness in a single continuum structure. The stiffness difference in these soft materials helps SPAs to control and limit their internal forces to realize different movements. Mainly, strain-limiting-layers (SLL) in SPAs are responsible for the movement control. The use of materials with constant stiffness in SLLs has limited the ability to change their movements on-demand. In this paper, a new SPA is developed with a variable stiffness SLL using Field's metal silicone. This SPA is able to generate two trajectories for the same pressure input and its trajectory is depending on the temperature of the SLL. The experiments revealed that the actuator is able to realize trajectories with approximately 10° difference for the same pressure input.