Date of Award

12-2025

Degree Name

MS in Mechanical Engineering

Department/Program

Mechanical Engineering

College

College of Engineering

Advisor

Alan Zhang

Advisor Department

Mechanical Engineering

Advisor College

College of Engineering

Abstract

This thesis presents the design and evaluation of a vacuum-actuated, origami-based soft robotic gripper. A custom Sea Urchin crease pattern forms a lightweight folding skeleton that collapses radially under vacuum. The system emphasizes low cost and accessibility through laser cutting, 3D printing, and silicone molding. The Sea Urchin geometry was selected after digital and physical screening of candidate crease patterns for smooth folding, low strain concentration, and uniform inward motion. The folding skeleton is laser cut from 4 mil drafting film and folded into a compliant core. Four membrane configurations were developed: an origami gripper with a 36-inch balloon (Design 1), an origami gripper with a loose silicone liner and balloon (Design 2A), a version with a tight silicone liner (Design 2B), and a fully molded silicone enclosure (Design 3). Silicone components were cast using resin-sealed PLA molds, producing smooth and consistent membranes. The balloon-based designs enabled large geometric collapse, while the molded silicone enclosure provided improved robustness.

Vacuum actuation was supplied by a 24 V diaphragm pump with microcontroller-based pressure feedback, allowing stable control from 0 to −50 kPa. Experiments on a Quanser QArm showed that all designs could grasp and transport objects of varying stiffness and shape, with the loose silicone-lined Design 2A performing best due to its deep collapse and smooth contact layer. Static pull-out tests revealed a predictable but non-monotonic relationship between vacuum level and holding force, with strength ranking from weakest to strongest as Design 3, Design 2B, Design 1, and Design 2A. Contact-force testing showed smooth force buildup across vacuum levels, and grape-handling trials confirmed that Design 2A could manipulate delicate fruit without bruising.

Overall, the results demonstrate that origami-based vacuum actuation offers a practical, tunable, and low-cost approach to soft robotic gripping. By adjusting membrane material, thickness, and coupling, the same origami core can be optimized for both gentle manipulation and stronger grasping tasks.

Download

Share

COinS