View Full Version : [Project] Cronos - 4 DoF Hexapod

06-30-2016, 01:26 AM

I think it's time to present my big hexapod (I named it Cronos):


This is a 4 DoF robot, using 24 TowerPro MG996R servos. It is controlled by a BeagleBone Black, using a custom cape (mostly a breakout to connect up to 32 servos), with assembly code on PRU to drive them synchronously.

I also wrote Py4bot (http://www.py4bot.org) a complete framework in Python to drive the robot.

This robot (which is the second one I build, after a small prototype), walked for the first time last saturday, during the Journée Portes Ouvertes of the Laboratoire Ouvert Grenoblois (https://www.logre.eu/wiki), a french hackerspace.

There are still a lot of things to do, on the robot itself, and on the framework, but I'm really happy to have reached this point :)

Future devs are:

test legs sensors (simple switchs) to detect floor, and so allow the robot to walk on non-flat surfaces;
switch to RPi3, using PCA9685-based boards to connect servos. I will be able to replace PRU code by simple Python code (using several process to take advantage of multi-cores), and so generate smarter trajectories;
rebuild the servo bracket mount (simpler and stronger);
find a better way for wiring;
design a new robot (better look) with arm+grip;
fix and improve the Python framework.

This is a long term project, and it will take me some months to achieve all this, but it is fun!

Thanks for any feedback.

06-30-2016, 05:05 AM
Nice project! Looking good. Is it ABS printed parts?

06-30-2016, 05:18 AM
Nice project! Looking good.

Thanks :) Your famous T-Hex was a big source of inspiration!

Is it ABS printed parts?

No, it is PLA. Black filament is from Capifil (http://www.capifil-extrusion-plastique.fr/en), a french company; they are new to 3D printing, but their filament is good. They are working on new colors... Silver filament is also from a french company, Filo3D (http://www.dagoma.fr/categorie-produit/filo3d). This one is expensive, but great to extrude.

06-30-2016, 10:29 AM
Looks great! I always like seeing large hexapods.

06-30-2016, 01:26 PM
Very cool. Nice progress so far. Please keep us updated as you move forward. Also, more pictures and videos are always good. :)

07-01-2016, 12:25 AM
Thanks, guys! I will make some more pictures and videos (to show differents gaits).