Nader Ahmed

M.S. in Robotics from Northwestern University

The Allegro Hand is a robotic hand with four fingers and 16 degrees of freedom. In this project, it is used to play a challenging Simon Says game with a human player. The hand performs increasingly longer sequences of gestures that the player must mimic in the correct order.

Video Demo

Disclaimer: The ring finger of our hand currently has a broken gearbox at its base joint. Once it is repaired the video will be re-filmed with some more interesting gestures!

System Overview

Simon Says block diagram

Planning & Control

The MoveIt setup assistant was used to generate the allegro_moveit_config package. For generating collision-free point-to-point (PTP) trajectories, the PILZ Industrial Motion Planner was used. The planning is performed in moveit_controller within the control_hand package and then interfaces with can_communicator.

In can_communicator, the BHand library generates desired torques using PD control to drive the error between the desired and current joint positions down. Since one of the fingers of the hand was not functioning, some joints were enforced to have zero torque. This was restructured from a fork from SimLab robotics and wrapped in can_communicator within the ROS2 package.

Perception

The MediaPipe Hand Landmarker detects 21 hand-knuckle coordinates from a camera stream. A hand gesture classifier was retrained with custom configurations and then computes the most probable right-hand gesture. This model and classifier were integrated into the gesture_classifier node with a publisher. Stability criterion were added to ignore spurious classifications.

Game

The allegro_game node serves as the main game loop. It:
1) generates gesture sequences for the hand
2) sends them to the planner and controller modules
3) evaluates if the player has performed them with the perception module
4) increases difficulty each round

Future Work

  • Re-filming with the fixed finger, adding more gestures
  • Incorporating motions into the sequences
  • GUI? Sound? Games have a lot of potential routes!

Thanks to:

Matthew Elwin, Ritika Ghosh, Ananya Agarwhal, Zachary Alves

Check out the project → GitHub