Soft Robotic Gripper

From left to right: iterations of gripper designs and bending movement of finger caused by air pressure in internal chambers

Overview:

During my first co-op as a systems test engineering co-op at iRobot, I had access to industrial 3D printers such as Objet, Fortus, MarkForged, and HP platforms and I had to take advantage of the resources in the limited time. Being very interested in soft robotics, and having produced actuators by silicone molding, I explored the feasibility of printing an soft robotic actuator with an Objet printer with variable stiffness material printing.

Purpose:

  • To experiment with the feasibility of manufacturing a soft robotic
  • component with a Objet 3D printer
  • Exercise practical CAD modeling skills
  • Go through general procedures when designing with industrial 3D printers

Challenges:

  • Printer tolerances required some iteration and testing for better understanding
  • Interface between solid and flexible material needed to be substantial in area for secure adhesion
  • Air pocket number, depth, and height had to be experimentally optimized
  • Elastic modulus of the flexible material had to be experimentally optimized

Outcome:

  • Small samples with different elastic moduli were printed to verify their strength and flexibility
  • Finger modules were printed individually to verify the tolerances of the printers and the effectiveness of the fingers
  • Contact surface area and configuration was altered to create resistant and durable seals between the two materials and parts
  • Parts of the gripper were printed in a modular form for individual testing, and the number of air pockets, their depth, and height were verified and changed accordingly (palm, fingers, etc.)

Skills Learned:

  • Developed skills to work with industrial 3D printers (Objet variable stiffness printer): Printing assemblies, tolerances, and durability expectation
  • Applied PneuNets (essential design concept in soft robotics) in a gripper design