Vacuum-driven artificial muscles exploiting snap-through instability for fast and efficient actuation

In this study, we present a vacuum-driven artificial muscle capable of rapid linear contraction through snap-through instability. The actuator consists of a rigid 3D-printed skeleton enclosed within a sealed membrane. We investigate how material selection influences the instability and bistability behavior of the actuator by comparing two systems: 3D-printed PLA and Flexible 80 A resin. Using a combined experimental and finite element approach, we characterize the snap-through response. In particular, we assess the effects of material selection and loading conditions through a combination of quasi-static and dynamic cyclic testing. Experiments showed that the proposed artificial muscles were able to provide both reversible actuation and self-locking under varying applied loads. Peak performance was achieved with an actuation speed of ∼325.4 mm s−1 (PLA 100% infill under 0.1 kg load) and an efficiency of ∼50% (PLA 75% infill under 0.5 kg load) under relatively low vacuum pressures (−39–−69 kPa). These results compare favorably with vacuum-driven artificial muscles reported in the literature, highlighting the advantage of incorporating snap-through instability as the actuation mechanism.