A novel linear actuator called origami-based vacuum pneumatic artificial muscle (OV-PAM) is proposed in this study that can produce large forces (>400 N) with a contraction ratio >90% of the active length of the actuator. Moreover, some of the designs presented in this article can lift large loads with large contraction ratios at extremely low vacuum pressure (≈10 kPa). This actuator consists of a sealed origami film chamber connecting a polygonal top and bottom plate with evenly spaced transversal reinforcements that prevent the chamber from contracting laterally at certain points of the actuator under vacuum pressure. As vacuum pressure is applied, both a tension force in the walls and a vertical force on the bottom plate of the actuator generate a large contractile force, and the force on the bottom plate can produce a consistent force throughout the entire motion. A quasistatic analytical model was developed that can accurately predict the behavior of the actuator and that can be used for actuator design. OV-PAMs are lightweight, have large contractile forces throughout their entire motion and large contraction ratios. It can also produce large forces at low pressures with large cross-sectional areas. Their versatility could make them well suited for a wide range of applications. They could take us closer to a future where robots can cooperate with humans to shape a better future.
Keywords: origami; pneumatic artificial muscle; soft robots; vacuum actuator.