Abstract:  In order to make grippers soft with good load capacity, inspired from the structure of the herbaceous plant stem and corolla, a spiral envelope gripper was designed similar to the corolla folding with rigidity enhancement scheme as the plant stem. Each claw actuator was spiral-curved, and the stiffener panel was embedded in each claw structure chamber to improve the output forces, with little influence on the deformation angle. The soft actuator also possessed lower hysteresis with stiffener panels. The soft gripper was fabricated, assembled and tested. The testing results show that the soft gripper is light with small closing volume, good unfolding，enveloping and load capacity were obtained, which had good gripping effectiveness for axisymmetric objects, and effective for objects that may not be manipulated by traditional grippers such as non-axisymmetric objects, except for the corolla folding motions, and the gripper may around objects to enhance gripping effectiveness.

Key words: soft gripper, herbaceous stem, stiffener panel, light and ductile

摘要： 为了使夹持装置柔软度和承载力兼备，受草本植物茎与花冠结构启发，设计了类似花冠收拢的螺旋式包络和仿植物茎刚度增强方案，每个夹爪呈螺旋状弯曲，通过在夹爪结构内逐个腔室横截面方向嵌入筋板来增大末端输出力，在对变形角度影响较小的条件下有效增大了夹爪末端输出力，并对改善软体执行器的迟滞性有显著效果。制作、组装软体夹爪进行了测试，试验结果表明，轻韧型软体夹持器在自重较轻和收拢尺寸较小的情况下，具备良好展开、包络和承载能力，不仅对轴对称形物体有良好的抓持效果，对于传统夹持器难以夹持的非对称形物体，除花冠式收拢动作外，夹爪还能缠绕物体以增强夹持效果。

关键词: 软体夹持器, 草本植物茎, 筋板, 轻韧