Abstract: To study the actuation characteristics of soft actuators and their bionic applications, a soft foldable actuator was designed based on Kresling crease pattern by using a symmetrical structural form, which could achieve fast actuation, generate only axial contraction without torsion(single-degree-of-freedom linear motion), and had the features of large contraction ratio and strong load capacity. Based on the principle of work equilibrium and combined with the geometric theory, theoretical modeling and experimental research of the soft foldable actuators were carried out to explore its deformation characteristics. The results show that the theoretical and experimental results are basically in good agreement. The contraction ratio increases with the increase of vacuum pressure. Under the same vacuum pressure, the larger the load, the smaller the contraction ratio. At the same contraction ratio, the heavier the load, the greater the vacuum pressure required by the actuator. The influences of different parameters on the actuation performance of the actuators were further analyzed, within the adjustment range of different parameters, the smaller the wall thickness, the smaller the relative angle and the larger the side length of the actuators, the better its performance including the contraction ratio and the bearing capacity. Based on the above results, a tandem soft foldable actuators were optimally designed and was mounted on a bionic humanoid leg, which may realize different functions such as flexion and extension, running, kicking a ball, and adsorbing.

Key words: soft foldable actuator, actuation characteristics, contraction ratio, vacuum-driven, bionic

摘要： 为研究软体致动器驱动特性及其仿生应用，采用对称结构形式设计了一种基于Kresling折痕图案的软体可折展致动器，可实现快速驱动，只产生轴向收缩而不发生扭转（即单自由度直线运动）,兼具收缩比大和负载能力强等特点。基于功平衡原理并结合几何学理论对该软体可折展致动器进行理论建模与实验研究，探究其变形特性。结果表明：理论与实验结果基本吻合，收缩比随真空压力的增大而增大；在同一真空压力下，负载越大，收缩比越小；在相同收缩比下，负载越大，致动器所需真空压力越大。进一步分析了不同参数对致动器驱动性能的影响，在不同参数调节范围内，致动器的壁厚越小、相对角越小、边长越大，其收缩比、承载能力等性能越好。基于上述结果，优化设计出一种串联软体可折展致动器，将其安装在仿生拟人腿上，能够实现屈伸、跑步、踢球、吸附等不同功能。

关键词: 软体可折展致动器, 驱动特性, 收缩比, 真空驱动, 仿生