The effect of scaling on the performance of elastomer compositeactuators

摘要

Compact actuation that is integrated into a structure's material system has the potential to provide rapid structuralreconfiguration while reducing weight. The effect of scale (diameter, overall length and segment length) on theperformance of cylindrical fiber-reinforced McKibben-like Rubber Muscle Actuators (RMA) was investigated. An"activation" pressure was observed for all actuators at a value that depended upon the actuation construction. Uponpressurization past the activation threshold, the overall force, stroke, and work capacity increased with increasingactuation length and diameter. The actuation force per unit RMA cross-sectional area was predicted, and experimentallyobserved, to be roughly constant after activation. By segmenting a longer actuator, a larger contraction and loweractuation force could be achieved. Though actuation forces decreased as actuator diameter and length decreased, theforce per unit actuator volume was shown to increase with decreasing diameter including a roughly 4-fold increase inforce/volume between the 0.5" and 0.05" actuators. However, due to the small amount of total contraction for the smallerdiameter actuators, the relative work per actuation volume was decreased by roughly 35% in comparing those sameactuators. Thus, small diameter RMAs have great potential to provide needed linear actuation force within adaptivematerial systems.