Winning Drive Train

[dipmeinaluminum]

so after a fun 2009 season, all the ideas about 4 wheel drive, 10 wheel drive, drive train with fans on it, and all that jazz.....what was the most effective drive train? what style had the most traction? Teams with the KOP 4 wheel drive train, what did you do to improve traction?

[delsaner]

At one of the regionals i went to, the winners, used two fans on back corners of their robot, which seemed to be very effective. Our robot had 12 wheels, each side having 3 rows of 2. It is a matter of testing different wheel sets on the regolyth (or however you spell it), and seeing which wheel set was the most effective.

[dipmeinaluminum]

Originally Posted by delsaner

At one of the regionals i went to, the winners, used two fans on back corners of their robot, which seemed to be very effective. Our robot had 12 wheels, each side having 3 rows of 2. It is a matter of testing different wheel sets on the regolyth (or however you spell it), and seeing which wheel set was the most effective.

12! and how did you think you did as far as speed and traction?? lets say 4 wheel KOP? who won that shoving match?

[delsaner]

As far as I remember, we did pretty well with shoving and pinning. As far as speed and traction, both were average, but definitely could have been better.

[Taylor]

We had a 6-wheel 4WD system (the rear wheels were doubled up), and we had no trouble pushing anybody around. We also had great control.

[Josh Drake]

We did the swerve this year. It helped to prevent us from getting pinned. 2753 added the fan and it seemed to help them.

[BrendanB]

Our team had 4 wheel drive for GSR and we added traction control for Atlanta. The traction control really helped. We had no problem pushing people around- http://www.thebluealliance.net/tbatv/match/2009cur_qm67

[JVN]

Anybody have anything quantitative to share? Anybody? Anybody? Bueller?

[Foster]

We had the 6+1=3 drive. Normal mode was six driven wheels in tank mode. Switch to two front wheels and the third wheel mounted 90 degrees to the others, located just in front of the trailer hitch. The third wheel dropped down lifting the frame and the back four wheels up to put all the weight on the front two wheels. With the six wheels we could push most teams around. The three wheel drive allowed us to "twitch the hitch" and swing out of some pinning situations.

[FRC4ME]

We used six wheel drive. Each side had two (doubled) back wheels and one front wheel. One CIM was driving each side through a SuperShifter (which, ironically, we never used).

We had a simple joystick ramp-up for a while, which worked okay. Towards the end of Atlanta, we developed an encoder-based traction control that worked great; its too bad it didn't see very many matches.

As a member of the programming team, it was difficult initially to convince the build team that more wheels would not actually improve traction. Then, they wanted to leave the front two wheels undriven (i.e. throwing away ~40% of our traction). Yay for physics!

[Tom Line]

This is not really quantitative, but....

The mentors on our team spent a lot of time watching the pushing matches trying to determine what drive train was the best.

Our final conclusion was reasonably simple: Whomever went into a pushing match with the most momentum initially won nearly all the time, regardless of their drive train.

We played with our gear ratios to improve our speed, and discussed changing our wheel distribution to change the weight on different wheels to improve turning, but in the end most teams proved that 4 wheels was just as good as any other option.

Some of the 'fastest' teams out there, like Hot, didn't even use traction control (at least they weren't using it in the Michigan regionals).

[techtiger1]

I just want an answer on why the mods let this thread happen for this game 2009 and traction shouldn't be in same conversation. Next 1251's robot was 4 WD with some traction control and a one speed custom gearbox about 7ish fps. Saying this we were just fine with traction for 2009 in fact it was one of our strong suits. We made the robot weight as close as possible to the limit 119.9 and had no problems basically moved every robot we needed too at the Fl regional except 233 who had an amazing traction control program. Saying all this we could still be pushed sideways if another team had momentum no matter what happened. The fans seemed to work well for some teams at gaining speed but not really for gaining a whole lot of traction. Other then that there was no real way to gain an advantage on traction this year.

[IKE]

Quick bit of Quantitative.

Wide stance 4 wheel steer crab. We initially geared for the same top speed as the "kit" and that was too slow (7fps I think). We got scored on a lot, and chased kit bots all over the field. (1st competition)

When we geared up to go faster (approximately 25% faster) (9-10 fps), we were able to score on "kit" chassis bots easier and able to run away and run down competitors better. This also reduced spin-out during launch, but a measured traction control was implemented shortly after that, so some bets are off. (additional competitions).

Observations. Wide stance bots were observably more manueverable (4x4 crab and fixed and 6x6 short stance) than long wheelbase 4x4, and even most long stance 6x6. Mathematically, wide stance, this gives better leverage at turning/swinging the trailer. It does however reduce straightline driving stability without Gyro-assistance.

[Adam Freeman]

Originally Posted by Tom Line

Some of the 'fastest' teams out there, like Hot, didn't even use traction control (at least they weren't using it in the Michigan regionals).

Not sure where you got your information on the quote above, but I can assure you we had some version of traction control at all events we attended this season. I can only remember one occasion when we ran a match with it turned off, and that was b/c we attempted to try a new version that was alittle too slow on response.

With regards to drivetrain, we had a wide - 6 wheel drive system with the rear wheels raise about 1/16" to allow for some "rocking" between the front and rear wheels. Not sure what effect it had on the bot, I think it just made my counterpart feel better. There was no quantitative measurements taken to confirm or deny its effectiveness.

In terms of pushing power, once we finally worked out our traction control issues, we could wiggle our way out of most issues. But, we were not a pushing robot by any stretch of the imagination.

My thoughts were why push when you could be scoring??? I guess it worked out in the end

[Tom Bishop]

We used the AM Toughbox kit transmissions on a wide 4-wheel drive, but changed out the stock gears. That changed the ratio on the trannys from about 12:1 to 5:1. Decreasing the torque made spinning out less likely, and made the robot quite a bit faster, although harder to control. It was good to be fast though

We weren't really too interested in pushing, our game was more scoring-oriented.