The CAD is slightly messy (as usual) so this is how we try to organize the document. As each subsystem goes through its design process, new versions are made and named using titles like Arm 1.0. Versions with a .5 are designs that never hit production. Along the same lines, versions with a .0 did hit production. Some of these CAD models are not exactly what we have in real life however the main assembly “TARS” is the closest thing to real life. You will also find old versions of TARS called “Robor” which is not a typo… well it was at one point but we have embraced it now.
Our intake took inspiration from 3847’s and 8177’s Chief Delphi threads. Thank you for providing awesome resources to the FIRST community!
In the next two weeks we hope to release a whitepaper going into more detail on things we found while designing and building this robot.
Here is a list of materials used to make the robot and where we got them: TARS BOM. I left out things like Motors, wires and raw materials like sheets of steel or poly since those are hard to source and people have preferences on suppliers. We did have a limelight on TARS but it was never used so I didn’t add it to the list. I hope I got everything, but I may have missed a couple of items.
Since we do not have much documentation on our robot to share with you right now, if you have any questions feel free to email us at email@example.com
We are also releasing our code: GitHub - FusionCorps/2023-Ignition
Here are some bullet points about the code from our lead programmer Andrew Oliver (@CrazyMetic):
• Custom swerve code built-on from 2022, with features such as wheel optimization and a closed loop ramp limit to prevent wheel slip during driving. Also comes with a custom odometry class, though we ended up using the WPILib one instead.
• Arm control via setpoint that uses an algorithm to move through the robot safely without needing to implement inverse kinematics and path generation. Motion magic control on the pivot motors prevents excess lash.
• Autonomous driven by PathPlanner (Thanks 3015!), with steps allowing us to modify paths separately on each side of the field.
• Single driver setup keeps control focused and simple.
No. The exact gear ratios can be found in the Constants file in our code.
If I recall correctly, we switched out the wrist gearboxes from 2 5:1 stages and 1 4:1 stage for a total of 100:1 to 3 3:1 stages in addition to an additional 2:1 reduction via sprocket for a total of 54:1 to increase the speed of the wrist while also reducing lash introduced via the MAXPlanetaries.
I’m not as sure for the arm base, but I do know we definitely decreased the gearing at some point in order to speed the arm up.
If you want to confirm any of the ratios, I would just cross reference the CAD with the code’s constants, since I know those are up to date.
Poly is pretty resilient even if it has been bent. These parts are meant to absorb collisions from the arm going astray (due to getting hit or a malfunction) so even if they broke they would have done their job to an extent. We had many hits to them from external robots and they never broke.
How have you guys seen that intake work out for you with cubes? Have you seen any problems with dropping pieces? I see most teams have a wide part and a skinny part like the everybot intake but you have just the skinny on the end. You also have one of the rollers with a tube and the other with the Churro shaft. How do you choose this design vs other designs?