Aracna: An Open-Source Quadruped Robotic Platform

Aracna is a new, quadruped robot platform which requires non-intuitive motor commands in order to locomote and thus provides an interesting challenge for gait learning algorithms, such as those frequently developed in the Evolutionary Computation and Artificial Life communities. Aracna is an open-source hardware project composed of off-the-shelf and 3D-printed parts, enabling other research teams to modify its design according to their scientific needs.


Design Considerations

Aracna was designed to overcome the shortcomings of a previous quadruped robot platform, whose legs were so heavy that the motors could not reliably execute the commands sent to them. We avoid this problem by locating all motors in the body core instead of on the legs and through a design which enables the servos to have a greater mechanical advantage. Specifically, each of the four legs has two joints controlled by separate four-bar linkage mechanisms that drive the pitch of the hip joint and knee joint. This novel design causes unconventional kinematics, creating an opportunity for gait- learning algorithms, which excel in counter-intuitive design spaces where human engineers tend to underperform.

Code, Drivers, Design Files

All of the code, drivers, and STL files necessary to 3D print your own Aracna are available on GitHub. The Aracna codebase is currently in the process of being rewritten from scratch to improve flexibility and usability.

Contact Sara Lohman, Jason Yosinski, Jeremy Blum, or Eric Gold with any questions. If you'd like to improve our code, feel free to fork the repository and submit a pull request on GitHub.

3D Printing Aracna

Below is a short video of Aracna being 3D printed on an Objet Connex500 3D printer:


Read more details and design considerations in our paper, presented at ALife 13:

Sara Lohmann, Jason Yosinski, Eric Gold, Jeff Clune, Jeremy Blum, and Hod Lipson. Aracna: An open-source quadruped platform for evolutionary robotics. In Proceedings of the 13th International Conference on the Synthesis and Simulation of Living Systems, 2012.

Other projects at the Cornell Creative Machines Lab

  QuadraTot, a earlier 3D printable robotic platform, a site where you can evolve your own 3D shapes

  AI vs. AI: Two chatbots talking to each other, a research video that went viral in August 2011