Ben Cazzolato

Justin Fong

Simon Uppill

Ballbot

Ben S. Cazzolato, Justin Fong and Simon Uppill

Background

Mobile robots that locomote with wheeled drives are slow and awkward, with wide bases providing static stability. In many applications what is needed is an entirely different approach to locomotion: mobile robots that are safe; dynamically agile and capable of graceful motion; slender enough to easily manoeuvre in cluttered, peopled environments; and which readily yield when pushed around. Intelligent machines of this sort can only be achieved with dynamic stability. Researchers at the Mircrodynamic Systems Laboratory at CMU have developed the Ballbot to begin to address this issue.

Ballbot balancing in the CMU motion capture lab, with Ralph Hollis looking on.

After the CMU Ballbot took the world by storm there has been a number of reproductions including one by Tohoku Gakuin University:

Tohoku Gakuin University Ballbots

Very recently a LEGO Mindstorms NXT ballbot, developed by Yorihisa Yamamoto, was posted on the web. See the OSEK Website, Mathworks File Exchange or the Youtube video. Another very nice ballbot is Rezero built by honours students at the Swiss Federal Institute of Technology, Zurich.

Project

This honours project involves the design an build of two ballbots: the first using LEGO Mindstorms NXT loosely based on the NXT Ballbot (Self-Balancing Robot On A Ball) Controller Design, and the second will be a full-scale device combining features incorporating the ballbots of CMU and TGU.

The project achieved the following tasks:
1. Design and built a ballbot from the standard Mindstorms NXT kit.
2. Built a solid model of the system using something like: LEGO Solid Modeling or Ldraw.
3. Built an instruction manual so that others can replicate the system. Needs parts count and step by step instructions.
4. Derived a dynamic model of the plant.
5. Designed a controller to stabilise the plant.
6. Built a Simulink model of the plant.
7. Built a VR model of the plant (by exporting solid model) and linked to Simulink.
8. Tested controller in Simulink simulation.
9. Tested controller in real life.
10. Drive the ballbot around via Bluetooth handset and impressed everyone.
11. Documented all of the above. 12. Repeated the entire exercise for the full-scale system.

The completion date for the project was October 2009.

The videos below shows the first stable motion of the Lego NXT Mindstorms Ballbot and the Full-scale Ballbot built for this project.

The video below provides a nice summary of the project