Driving on Regolith

What were some of the better drive systems on regolith? How well did the usual WCD work? Were you even able to swerve on regolith?

In addition to different drive systems, how about motors? Was it necessary to put all 4 cims on drive? Did it really give you an advantage or were two just fine?

I know my team had success with a three wheel drive with the back wheel being a powered caster. All three were run on 775s, not a single cim on drive. How about your team?

After surfing Chief Delphi with no luck I felt it was finally time to ask.

WCD basically replaced the wheels with the allowed ones. I believe 254/968 took out their second speed too. Swerve did work on regolith. In fact, it was a great year to use swerve, because you didn’t need to put as beefy motors to change the angle of the modules.

A lot of teams ran 2 CIMs instead of the regular 4. Instead, many teams added fans to the back of their robot, and traction control using an encoder and follower wheel.

Most “standard” drive configurations worked just fine on regolith, or at least as fine as you could work on regolith. Teams that incorporated non-powered casters with encoders to implement traction control often gained an advantage, as did teams that fitted fans to the back of their machines.

Swerve was actually easier in 2009 than any other year. Since the machines broke traction with the ground so easily, a designer did not have to worry about side loads on the swerve module. This allowed them to be built lighter, and helped some teams on the fence about going to swerve make the jump. Wildstang won the world championship that year with a crab drive, in part due to the super fast human load auto that their crab drive enabled.

Anything more than two CIMs on the drive was unnecissary. Again, you would break traction with the ground before you got anywhere near stall.

I thought the 775s didn’t come around until 2011…:confused:

548 had a pretty unique drive system that year. Swerve powered by 3 servos per wheel (total of 12 servos) with a banbot 550 or a fp powering each wheel. It was my rookie year but I remember us having a lot of tourque, our main job was pinning their best scorer, but not overly fast. The swerve worked well for us and we received a lot of awards for it. The Pod!

From what I saw that year, wide drives worked well. We had pretty good traction and maneuverability with 4 wheel 2 CIM wide drive. Also, I can attest to the benefit of fans, as we played many matches with 121 who was wicked good with their fan. Also, we lost to wildstang and their swerve, so that worked too.

From what I’ve seen and from what our mentors keep telling me, 2009 was one of the best years for a swerve drive. The wide open field, slippery floor, and a lack of pinning restrictions gave swerve teams a HUGE advantage over the rest of the teams, as maneuvering out of pins was exponentially easier with a multi-directional drivetrain. We ran our usual crab setup (4cims, 1 per module) with traction control and saw awesome results.

Wide orientation robots with the COG as far toward the back (trailer hitch) as possible were the best performing skid-steer robots. Swerve also worked well. Anyone with fans also had a distinct advantage.

Depends on how teams implemented it.

Yes, some used swerve quite well.

No, using more two actually generally made it worse since it greatly amplified your chances of slipping. Dynamic friction is always less than static friction.

We drove tank drive, with 4 CIM powered wheels, two on each side. It worked pretty well for us. It would often skid, but we incorporated this into our strategy and learned how to skew into corners. Our lunacy bot was my favorite to drive, and, watching some footage of our matches recently, I was pretty darn good at it, too. That bot went wherever I wanted it to.

2815 used two 550-sized motors (Mabuchi? F-P? Been so long…) through AM Planetary gearboxes, through the standard 2009 kitbot (AM Toughbox, AM C-Base, the 2009 wheels) with a wide base. We saw little reason to do more.

(And it let us use four CIMs on the ball collector/power-dumper. When else can you get away with that?)

You used FP motors; the lower overall power and (relatively) high speed gearing helped reduce slipping (I was intimately familiar with your bot that year).

That was a fun year to design end-effects; no lack of available power (which sometimes presented its own problems).

I wish I could find pictures, but I believe 71 not only had swerve drive, they had fans that they could pivot to help them steer. As I recall, the fans were small, maybe 6" across, but they were powerful.
2009 was a fun year. Lots of intricate gameplay strategies that were often lost on the general public.

Our '09 robot has 4 wheel 2 cim normal drive. The other two cims were used on the airplane prop on the back :wink: I have been told that the majority of the thrust of the robot was from the fan and the wheels were more strong mechanisms than propulsion. Regardless it makes a great demo bot on those hot summer days

I’d imagine so.

This machine, along with Cyber Blue, won the inaugural DC regional and finalists at BMR. It blew away the competition. Some believe it also blew some orbit balls away from their trailer.

Sorry I meant some 550 equivalent I am just to used to saying 775s that it was engrained in my brain.

Such a great idea to put a fan on the back of your robot. For swerve, did turning your wheels perpindicular to an incoming robot provide any traction against pushing?
Also, did having two wheels next to each other help increase traction? Or was the increase not noticable?

I don’t know about other teams’ methodologies, but I was the driver for 1569 and with four wheel drive, 2 CIMs, no traction control, and an incredibly low center of gravity, there wasn’t a single robot we couldn’t push around.