The robot was designed in Onshape by Joshua Peterson (alum of FTC team Kraken Pinion). I (Alnis Smidchens) created this promotional video using Blender’s powerful driver system to create a full simulation of the very complex geartrain. Rendered in Eevee, edited in Kdenlive.
Full description (from YouTube):
This robot controls four mecanum wheels using only three motors for full holonomic motion. How? Through 6 differentials and a complex gear-based drivetrain. Each motor controls one degree of freedom—the top motor controls rotation, the middle motor controls lateral movement, and the bottom motor controls longitudinal movement.
This video shows the fully-functioning drivetrain in action in rendered footage as well as real-world footage of the physical robot driving around with a remote control. The robot is uniquely mobile in that all three degrees of freedom are controlled using exactly three motors, unlike traditional mecanum drive bases with one motor per wheel (for a total of four motors). Thus, it can move in any direction at any time.
Onshape model link: https://cad.onshape.com/documents/039d90381644dad86f131915/w/9de01be2421518eba3ef6f53/e/c3a5fb31123dfc8af82c16a0
GitHub code link: https://github.com/joshuapeterson210/threemotormecanum
Feel free to ask any questions! I’m currently cleaning up the .blend file and I’ll hopefully post it sometime soon.
(repost because it didn’t embed properly the first time)