3D Printed Soft Robotic Gripper

02/2025 - 04/2025

Project Description

Designed and fabricated an adaptive, soft robotic gripper capable of handling delicate and irregularly shaped objects—from a hair tie to a small cup of water—without causing damage. The goal was to create a robust, low-cost end-effector for a proposed autonomous fruit-picking robot, addressing the key challenge of gently grasping produce of varying size and ripeness.

Skills Used:

Technical Skills: Onshape (Multi-body Design), Multi-Material 3D Printing, Research Synthesis, Soft Robotics Principles
Engineering Skills: Design for Additive Manufacturing (DFAM), Material Selection, Mechanism Design
Soft Skills: Self-Directed Learning, Conceptual Integration, Problem-Solving

Key Contributions

Researched academic papers on soft robotics to establish a foundational design approach.
Synthesized concepts from multiple research designs to create a novel gripper optimized for accessible FDM 3D printing.
Successfully prototyped a functional gripper using a dual-material approach (rigid PLA actuator + flexible TPU grip), demonstrating effective adaptive grasping.

Research-Driven Design Process

I began by analyzing existing soft robotic gripper designs in academic literature. Two key papers inspired the final approach:

University of Auckland's Adaptive Gripper

Thin flat cut or printed PET layer coated in poured silicon

Boston University's Adaptive Gripper

0.127mm thick PET laser cut and then heat treated to a curved shape

Auckland's gripper was much closer to my use case, but their poured silicon manufacturing method was labor intensive and wouldn't translate well to more rigid TPU. Boston's gripper would be simpler to manufacture, but making a metal form for heat treating and waiting for it to bake would be expensive and time consuming.

To get the best of both worlds, I combined the designs, mimicking Auckland's pointed oval cutout and thickness but making the neutral state curved like Boston's gripper to encourage the printed TPU, which is much stiffer than silicon, to fold.

IMG_4006.MOV

Demo of Subscale Gripper

Rapid Prototyping

To be sure that my TPU gripper would perform as expected before devoting hours of print time to it, I performed a subscale test, operating the mini gripper by hand to verify that it could grasp and lift a range of objects.

Linear Actuator Design

With the subscale prototype validated, I moved on to designing a 3D printed linear actuator which would operate the soft gripper.

Actuated by a Servo motor and assembled using standard hardware, the actuator was simple, functional, and easy to assemble.

CAD of linear actuator

IMG_5056.MOV

Demo of Fully Integrated Gripper

Final Integration and Testing

After assembling the gripper and linear actuator, I tested the gripper on a variety of objects ranging from a hair tie to an orange to a cup of water.

I found that material roughness played a large role in how securely the gripper could grasp an object, and took note that for future iterations a high friction rubber surface on the gripper's inner face may be useful.

Results & Key Takeaway

Functional Prototype: The gripper successfully demonstrated adaptive grasping, securely holding objects of varied sizes, weights, and fragility.
Proof of Concept: Validated that a research-informed, low-cost soft gripper is feasible for agricultural robotics applications using accessible manufacturing techniques.
Key Takeaway: This project underscored the power of research-informed design. By understanding the principles behind advanced research, I could adapt and implement them within the constraints of available tools to create a functional and effective solution.

Next project

Page updated

Google Sites

Report abuse