I’m wondering if anybody has experience using pneumatic wheels on an FRC robot before. How do they work for traversing obstacles? How do they compare to more standard FRC wheels? I’m also wondering what other drivetrains/wheels teams have used to traverse field obstacles.
2013, 2014, and 2015 (not counting scoring platforms) were all devoid of serious obstacles in the field, and as a result there are many teams that have never had to deal with them. I’m particularly interested to hear how teams approached the 2010 and 2012 games.
Having a drop-down ramp was a popular way of getting across the bump in 2012. Designing your frame to have a larger angle of attack is also one method of being able to get over obstacles without having to resort to bigger wheels.
I always think of 86’s bot from 2010 when I hear pneumatic wheels. Here’s a video that shows them traversing the bump a couple of times.
Unfortunately I can’t comment on them directly since none of my teams have used them.
Having a drop-down ramp was a popular way of getting across the bump in 2012.
180 did this in 2012 with 6"/4" (I forget) wheels. We had no problems crossing the beam with this method.
That’s great for powering over the bump, inertia for sure.
Thinking back to 2010’s bumps, I’ve been pondering a software-activated mechanism that features a rear-mounted pneumatic mechanism “stinger pair” (two pistons, on each side of the rear bumper); it would be activated when the pitch (rotation about the Y axis) angle exceeds X% (an angle that would imply the front wheels were not making contact w/the ground, perhaps confirmed by motor current that is less than the rotational velocity/mass would imply) that would lift the back end and force contact with the front wheels. It’d likely be slower than the beachbot in the video, but it might be kinda cool…
Then there was the mixed pneumatic/normal wheel setup 330 used back in '04 to climb a 6" step. 12" pneumatic Skyway wheels, 6" normal ones. The normal wheels were in front, with a sloped frame to get them up to where they could get a grip. The 12" wheels drove the robot while the 6" ones got to a grip, then the 12" did their climb and up the robot went. It wasn’t very fast–but it didn’t need to be; that climb was autonomous and if all went well, the robot would spend all but auto and the 15 seconds or so after that hanging around in scoring position.
Over the summer we made an off road robot that was an 8 pneumatic wheel drive. All though it wasn’t field obstacles they get over most rough surfaces without losing traction. A team I help mentor used a 6 wheel drop for 2012. It got over the bump in the field really easily but bounced around when it landed.
pneumatics tend to be a bit “bouncy” as they have more deflection than most FRC wheels.
When contacting or impacting obstacles, this is generally a good thing. When trying to get precise positioning of a large arm, this bounce can look like bobbling.
In 2010, 33 went over the bumps by lifting the middle wheel which caused a smoother transition. This worked very well until States that year when we noticed the rear axle was bent. Basically as the driver got more confident and faster, he was literally driving off of the bump. This meant that the back wheels tended to see repeated 8-10" drops multiple times a match… So the axle had to be “beefed up”.
Also in 2010, there was a very good team that was an 8x8 with hard wheels that nearly knocked themselves out of elims by what we assumed was a CRIO reset after crashing over the bumps hard.
I saw a lot of broken wheels and axles in 2010 and 2012 due to impacts.
As others have pointed out, using angled skids can help go over bumps too.
This was one of my favorite pictures from 2012:
While mentoring team 3677 in 2012 (Rebound Rumble), we used 8in andymark pneumatic wheels on risers to get over the divider. It was quite a bouncy experience. We had no issues at slower speed, but anything close to regular drive speed almost caused us to flip.
