CHAP: The CHeap Arm Project

Welcome to the CHAP homepage, dedicated to a Low-Cost Tele-Operated Mobile Manipulator. Our website is still a work in process.
We are currently adding source code and designs for CHAP as well as supporting research.
Please take a look around and feel free to support development or fork the designs for your own project!



  1. University of Plymouth and private donations.


  • The mobile manipulator is made of distinct components that can be individually redesigned. 


  • Built the mobile platform with three MX-28 dynamixel servos and omnidirectional wheel. Programming its motion programmed either from a Tartarus Board (Plymouth University Design) or from Raspberry Pi using Python and the USBToDynamixel interface.
  • Built the "Mast" and its lifting mechanism for robot arm. Moved to RX-64 + pulleys system for lifting force doubling. Added stop switches at top and bottom.
  • Gripper
  • Teleoperation interface.
  • CHAP was demonstrated at the exhibition Off the Lip 2016, with only one set of batteries needed for 4h of operation. Children remote-controlled the robot for hours and had fun. The good news is that CHAP passed the children's test without any damage or failure.
  • Run user tests (see the paper in the Research section).

To do:

  • Replacing some of the Dynamixel Servos with cheaper alternatives.
  • Make gripper control more convenient.
  • Design a "smaller" version - see research paper.
  • Learning object-specific fetching procedures.
  • Promoting and supporting building a copy of CHAP elsewhere.
  • Refine instructions - best done while helping someone building it.

Open Source

All materials used in the development of the CHeap Arm Project are open source and fully available on GitHub. Designs and software can be found below:


Contact Details

Guido Bugmann
Dominic Cassidy