Mastering Motion
The Cubli is a 15 × 15 × 15 cm cube that can jump up and balance on its corner. Reaction wheels mounted on three faces of the cube rotate at high angular velocities and then brake suddenly, causing the Cubli to jump up. Once the Cubli has almost reached the corner stand up position, controlled motor torques are applied to make it balance on its corner. In addition to balancing, the motor torques can also be used to achieve a controlled fall such that the Cubli can be commanded to fall in any arbitrary direction. Combining these three abilities – jumping up, balancing, and controlled falling – the Cubli is able to ‘walk’. The Cubli was developed at the Institute of Dynamic Systems and Control, ETH Zurich.
The Cubli (illustration)
The Cubli jump-up strategy: (Left) Flat to Edge: Initially lying flat on its face, the Cubli jumps up to stand on its edge. (Right) Edge to Corner: The Cubli goes from balancing on an edge to balancing on a corner.
Publications
M. Muehlebach and R. D’Andrea, Accelerometer-Based Tilt Determination for Rigid Bodies with a Non-Accelerated Pivot Point, IEEE Transactions on Control Systems Technology, 2018
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M. Muehlebach, R. D’Andrea, Nonlinear Analysis and Control of a Reaction-Wheel-Based 3-D Inverted Pendulum, in IEEE Transactions on Control Systems Technology, 2016 (early access)
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M. Muehlebach, G. Mohanarajah, and R. D’Andrea, Nonlinear Analysis and Control of a Reaction Wheel-based 3D Inverted Pendulum, in Proc. Conference on Decision and Control, CDC 2013 (Florence, Italy)
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M. Gajamohan, M. Muehlebach, T. Widmer, and R. D’Andrea, The Cubli: A Reaction Wheel-based 3D Inverted Pendulum, in Proc. European Control Conference (Zurich, Switzerland), pp. 268-274, July 2013.
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M. Gajamohan, M. Merz, I. Thommen, and R. D’Andrea, The Cubli: A Cube that can Jump Up and Balance, in Proc. IEEE/RSJ International Conference of Intelligent Robots and Systems (Algarve, Portugal), pp. 3722-3727, October 2012.
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Talks
Haus Konstruktiv Zurich, Live robotics presentation at the art gallery Haus Konstruktiv, 2014
Prosieben Galileo television program, television coverage in one of the largest German-language channels, 2015
National Council Switzerland, live robotics presentation to the Science, Education & Culture Committee of the National Council, 2016
World Economic Forum, Live robotics presentation at the ETH-booth, 2017
Zurich.Minds, Gajamohan Mohanarajah, Switzerland, December 2013 | Video
Berlin.Minds, Gajamohan Mohanarajah, Switzerland, December 2013
VIDEOS
The Cubli: a cube that can jump up, balance, and ‘walk’, December 17, 2013.
The Cubli: A Reaction-Wheel-Based 3D Inverted Pendulum, January 17, 2013.
One-Dimensional Cubli Prototype, July 20, 2012.
Start Date: Feb 2011
End Date: When did this project conclude?
Lead Researchers
Michael Muehlebach
Gajamohan Mohanarajah
Raffaello D’Andrea
Concept
Raffaello D’Andrea
Additional Participants
Marc Corzillius
Past Participants
Felix Berkenkamp
Christof Dubs
Hans Ulrich Honegger
Michael Merz
Carolina Reuse
Sonja Segmüller
Igor Thommen
Tobias Widmer