Stronghold Drivetrain Review

[BoilerMentor]

I never thought I'd see the day that we'd use a treaded drive, but this was the year.

Basic:
Waterjetted, folded aluminum drive pods with custom pulley layout
AM Rhino Belts
Rhino pulleys (replaced due to cracking during build season)
Custom single reduction, single speed gearbox ~6:1
2 cims and 1 mini cim per side
static belt tensioner per side

Advanced:
3 pulleys at "ground level" center ~1/8" lower
2 pulleys at "frame level"
Bevel at each end to allow crossing in either direction
~26" Width (outside to outside)
~30" length (outside to outside at frame level pulleys)
~20" of floor contact per side
Belt tension was entirely subjective, but we never threw a belt

Control:
3 Talon SRX motor controllers per side
split stick arcade drive scheme on a game pad

Maintenance:
gearboxes regreased at each competition
pulleys inspected for cracking (none observed through competition season)
belt tension verified
belts never replaced

Observations:
Despite my aversion to treaded drives, I'm very pleased with the behavior and performance of our drive train this season. If the game required it, I think we'd certainly dust this one off and use it again.

Power availability is going to drive our design and gearing decisions in the future. The brown out situation lost us some matches we really should have won, or at a minimum cost us some time because of added difficulty in executing crossings.

If we were approaching this problem again, I firmly believe the choice to neglect to add suspension is the right one. Yes, it would have reduced the wear and tear on the robot from hard impacts, but from observing behavior of other treaded drives that incorporate suspension it would appear that the issue of appropriate spring rates and damping aren't trivial and can lead to really problematic behavior through defense crossings.

[Gdeaver]

We went with treads. This is what we did. Over all happy with the results.
http://wiki.team1640.com/index.php?t...II_Drive-Train

[Nightwing430]

Originally Posted by abbymarie

We used 8 inch pneumatic wheel in a 6 wheel drive train, using the belts from the Kit of Parts. It worked amazing for breaching the defenses, we never got stuck on anything! Tire pressure was never a problem, we maybe checked it once or twice.

This is what my team used for our drive train. We though it worked really well for breaching and we didn't have to check the tires that much either. Boulders were a problem for my team when we ran over them but I'm not blaming that on the drive train we chose. We also modified it to were it was tank drive which is what our robot last year used so we had more experience driving it like that.

[TheOrangeCrush]

Team 3026 Orange Crush is proud to present MecaTrak.


MecaTrak is a revolutionary and never before seen dual drive train that gives us the agility of mecanum wheels but by deploying two air cylinders it drops a set of custom made tracks to give us the needed power and traction for defenses and robot to robot challenges. The tracks are made of #35 attachment chain with riveted pads attached to the chain.

We started development in October 2015 and went through several iterations of prototypes before the final product made its way onto the competition bot.

Link to October 2015 Prototype
https://www.youtube.com/watch?v=2JImlM7Ed-Y

Youtube Video of MecaTrak
https://www.youtube.com/watch?v=z2TWEV4n0wQ

MecaTrak Specs

Mecanum

• 6 inch Andy Mark mecanum wheels
• Speed - 15 feet per second

Tracks

• Lifts the robot .5 inches off of the mecanum wheels
• #35 attachment chain with riveted pads
• Pads can hold a box at 25 degrees
• Speed – 8 feet per second

[1625Brennan]

on 1625 we used tank treads with a twist, we added omni wheels in the front by raising the tread, this allowed us to tighten the turning radius. Only the back pulley and omni made contact while on flat ground although when crossing a defense the tread would contact making it so we had little to no issues crossing. We had originally started with Brecoflex treads although after our first comp we opted to change to our Andymark treads due to wear. The only significant wear we encountered after that was damage to our omnis, they would "jam" and not allow a roller to move after repeated massive impacts. Our whole drivetrain was ran by Vex 775Pros, 2 powered each tank tread (4 total) and 1 for each omni (2 total) Overall we are quite pleased with our choices

[Valkonn]

Our unique butterfly module drivetrain really showed it's strength on the rock wall and ramparts compared to other robots in our tier. I really like it but feel like over-engineering our drive train left the rest of the bot really weak and it really showed when we got demolished in the Las Vegas playoffs.

Edit: Here is the max speed it could cross the rock wall: https://www.youtube.com/watch?v=ovvr1kig3ls

I'm a huge fan of 1671's drivetrain this year, that thing is a monster and comparable to 254's.

[techtiger1]

Biggest obstacle for Stronghold drivetrains=bumpers and bumper rules. We went with a custom tank tread system with suspension although it wasn't as advantageous as we hoped the team was happy with its performance.