Origami-Inspired Soft Gripper with Tunable Constant Force Output

TL;DR

The paper tackles the challenge of achieving stable grasping force with soft grippers. It introduces an origami-inspired Waterbomb-based panel that yields tunable constant-force output over a wide strain range, controlled by geometric parameters $dist$, $\alpha$, and $t_c$ and validated by buckling/post-buckling FEA and experiments. Key findings include near-constant reaction forces during compression, high torsional stiffness, and successful grasping of delicate and irregular objects. The work provides a pathway to safer, more adaptable industrial automation and human–robot interaction using soft, geometry-programmable grippers.

Abstract

Soft robotic grippers gently and safely manipulate delicate objects due to their inherent adaptability and softness. Limited by insufficient stiffness and imprecise force control, conventional soft grippers are not suitable for applications that require stable grasping force. In this work, we propose a soft gripper that utilizes an origami-inspired structure to achieve tunable constant force output over a wide strain range. The geometry of each taper panel is established to provide necessary parameters such as protrusion distance, taper angle, and crease thickness required for 3D modeling and FEA analysis. Simulations and experiments show that by optimizing these parameters, our design can achieve a tunable constant force output. Moreover, the origami-inspired soft gripper dynamically adapts to different shapes while preventing excessive forces, with potential applications in logistics, manufacturing, and other industrial settings that require stable and adaptive operations

Figures (8)

• Figure 1: Grasping a paper cup using (a) an origami-inspired soft gripper and (b) a rigid gripper. (c) Deformable modular gripper and (d) the corresponding reaction force–strain property (gentle and constant output force).
• Figure 2: Scheme of the origami-inspired structure and folding mode. (a) Geometry of single origami panel in each module. (b) Definition of the protrusion distance $dist$. (c) Planar geometry and folding pattern
• Figure 3: Modeling and simulations. (a) 3D modeling of the panel. (b) Simulation setup for the panel and module. (c) Numerically obtained deformation processes of the module in post-buckling analysis.
• Figure 4: Reaction Force-Strain analysis for different structure parameters, including (a) protrusion distance dist, (b) taper angle $\alpha$, (c) crease thickness $t_c$, and (d) scaling ratio $n$.
• Figure 5: Fabrication and assembly of the origami-inspired gripper. (a) Panel fabrication by (i) silicone casting and (ii) TPU 3D printing. (b) Assembly of the gripper.