Design and experiment of a variable stiffness soft manipulator for non-destructive grasping

With the advantages of high flexibility, high safety, and good adhesion and wrapping, soft robots have a wide range of application prospects in complex environments such as automatic production lines and medical surgery. By coupling an active pneumatic drive structure and an interference variable stiffness mechanism, this paper designs a soft robot based on a variable stiffness pneumatic actuator. Based on kinematic analysis and finite element simulation based on the segmented constant curvature method, the Lagrange equations are applied to perform dynamic analysis, which in turn verifies the variable stiffness performance and bending performance of the variable-stiffness soft robotic arm. The soft manipulator adopts the structural design based on 2 mm thickness, jamming mechanism and coupling fiber layer, which can effectively resist 0–2.5 N force without large deviation and be adjustable in the stiffness range of (0.025–0.12) N/mm, under the condition that the vacuum degree does not exceed 80 kPa. The stiff stiffness and bending behavior of the proposed soft manipulator show excellent performance and can be applied to industrial automation, medical devices and other operations.