Development of Ultralight Hybrid Pneumatic Artificial Muscle for Large Contraction and High Payload

This paper presents a novel pneumatic artificial muscle (PAM) that is able to generate a high payload and buckling pressure. The proposed actuator exploits open-cell foam, and 0.8 mm thick rigid rings to reinforce structure stiffness, and to implement stable contraction under depressurization. All components are embedded in a sealing elastomeric skin. The actuator can support 6.8 N of external load, which is 34.5 times greater than its own weight (20g). When depressurized, the actuator deforms stably, without buckling. The results of the preliminary experimental analysis show that it is able to contract up to 51.8% upon -80kPa, with a 5.6% hysteresis for pressure vs. contraction ratio. Moreover, a quasi-static model is proposed to estimate the actuator blocking force, of which the measured maximum value is 32.7 N at -80kPa vacuum. The presented actuator shows repeatable and reliable performance, providing a promising soft material solution for pneumatic driven movement.