Model T42 robotic gripper
Two fingers.
A careful grip.
Our team implemented the Yale OpenHand T42: an underactuated gripper built around tendon-driven fingers.
Model T42 robotic gripper
Our team implemented the Yale OpenHand T42: an underactuated gripper built around tendon-driven fingers.
01 · The mechanism
The existing OpenHand platform gave us a mechanical foundation to assemble, analyze and understand.
02 · Motion, made visible
Actuators pull the tendons. The fingers flex. This animated study makes that relationship easier to see.
03 · Look inside
The frame brings the fingers and actuators together. The layers separate here to reveal the assembly.
04 · Beyond the render
Our coursework connected MATLAB analysis with assembly, motor communication and calibration.

Four-person team · ROBO 204 · January–May 2026
Understanding a grasp, from the mechanism to the motor.
01 / Purpose
Implement and understand the Yale OpenHand Model T42 gripper, an existing tendon-driven platform. The platform design belongs to the Yale OpenHand project.
02 / Approach
The team used MATLAB analysis, assembled printed components and tendon-driven fingers, and worked with Arduino and Dynamixel control. Testing covered motor communication, calibration, speed synchronization, opening and closing, and basic grasping.
03 / Contribution
I led the build in a four-person team with Mohammed Muqeet, Obaid Alaleeli and Ibrahim Alhammadi. I ran the MATLAB analysis, assembled the fingers and routed the tendons, and calibrated the Dynamixel motors, then tested opening, closing and grasping.
04 / Demonstration
The film below is built from Yale’s original OpenHand fabrication CAD and animated in Blender to show how the tendon drive closes the fingers.
05 / Results
We assembled and calibrated the T42, synchronized the motor speeds and tested opening, closing and basic grasping. We built on Yale’s open design rather than designing a new gripper.
06 / Limitations
Finger movement depended heavily on tendon routing and calibration. We didn’t measure grip force or payload, which would be the next step.
07 / Lessons learned
Working from an established mechanism makes calibration, mechanical assembly, and communication between the controller and actuators central engineering tasks.
Next project
The Blender scenes and animations are illustrations made for this portfolio, not recorded results. The YouTube videos show the real robots and lab demos, and the AURORA film includes footage from the interactive learning demo.
The T42 scene uses the Yale OpenHand Model T42 CAD from the Yale GRAB Lab’s OpenHand repository, licensed CC BY-NC 3.0, with the assembly, materials, tendon path and motion adapted for illustration.
R. R. Ma, L. U. Odhner, A. M. Dollar, “A Modular, Open-Source 3D Printed Underactuated Hand,” ICRA 2013.
The Yale OpenHand Project is an initiative to advance the design and use of robotic hands designed and built through rapid-prototyping techniques in order to encourage more variation and innovation in mechanical hardware. Please visit the Yale OpenHand site for more details.