[FTC]: Climb or No Climb-That is the question?!

[pilum40]

We've been debating how to build our drive system for FTC this year. We're waffling between tank drives, a hybrid "half track design with the tracks in front and wheels in the back, a physical crawling style system (like a beetle), or just not dealing with climbing at all while trying to maximize points via other means.

Has anyone else worked through this quandry or are we the only team bending with the wind, prototyping our rear-ends off and generally being frustrated.

Any pearls o' wisdom would be appreciated.

PS: We've watched multiple videos and tried various combinations of wheels. They're lame in comparison to tracks. (at least today..lol)

Thanks for any help that could be given on this.

Steve Miller
Coach Team 10756 FTC
Coach Team 3355 FRC

[cadandcookies]

You definitely aren't the only team having trouble with the mountain. I think a lot of teams are either underthinking how they'll climb the mountain or overthinking their capabilities.

I'd recommend coming into designing your drive train knowing what you want your robot to do. There are a number of things that go into that-- when is your first tournament? What do you want to spend most of your time working on? Do you and your students have a solid grasp of drive mechanisms and the physics involved?

Based on videos and my team's experience, you can get up to the middle zone fairly easily with wheels, but getting to the high zone will be significantly harder. We decided that we weren't even going to worry about the high zone for our first tournament (December 13th), because there were more (and easier to get) points elsewhere in the game.

Having said that, there are a number of things can can make climbing to the middle zone with wheels smoother/easier-- making sure you have your weight in the right place, making sure your wheel spacing is good and your wheels are properly sized, et cetera. Many of the prototypes I've seen for climbing seem to have really narrow wheel bases, which might be nice for turning but won't help with the mountain.

Another suggestion would be to actually physically try your own drive trains out-- if you don't have or can't afford a mountain of your own, you might try reaching out to another team and asking them if you can come over during one of their meetings. CAD can tell you a lot about the mountain, but (at least at the level most FTC and FRC teams are at) it can't substitute for physically trying your ideas on the mountain.

Hopefully that was somewhat helpful.

[DavisDad]

Originally Posted by pilum40

...PS: We've watched multiple videos and tried various combinations of wheels. They're lame in comparison to tracks. (at least today..lol)...

I think we're close to climbing both 30 deg and 50 deg sections: Prototype Climb Test 2.5

[wgardner]

Originally Posted by pilum40

Any pearls o' wisdom would be appreciated.

My quick thoughts:

1. You don't need to drive over the churros to score in the goals or to climb in the end game. You just need to drive on the mountain with your drive train above the white tape at the bottom two inches. There are lots of ways of doing the rest of the scoring from this position.

2. Virtually all of the tread-based drive trains that I've seen are all VERY low and even then they nearly all tip back over when they are in the high zone. I see a lot of videos with folks driving up in the high zone while somebody has their hands there to catch the robot. I don't see a lot of videos with these robots sitting entirely in the high zone or driving back down without tipping over. If they add other mechanisms on their robots above their drive trains, it may be VERY difficult for them to keep their balance if they dare to go into the high zone. I suspect most will stick to the mid-zone at most. The mid zone is worth 10 points more than the low zone in autonomous and the end game, which isn't much compared to putting a few pieces of debris into the goals.

3. It isn't legal to purposely deposit debris on your opponent's side of the mountain. However, I suspect that debris may end up there accidentally when teams are trying to score and miss the goals. The debris will then be stuck on the mountain by the churros. If your goal is to drive over any of the churros, make sure your drive train works when there are blocks or balls resting on the mountain by the churros, or you may find yourself unable to get as high as you planned.

Good luck!

[npbartelt]

Our team is just going to the mid zone and scoring from there. I think that having a system that can consistently dump lots of debris is far more important than the few points you get for being able to drive to the high zone.

[Gdeaver]

Climbing the 30 degree section will take some work but many teams should be able to accomplish it. The 50 degree section is another story. The problem is center of mass and the torque force from driving the wheels makes the robot want to rotate off. Tracked robots fair a little better but as soon as parts are added to accomplish other tasks the COM goes bad. Even if a tracked robot is designed and can climb the mountain there is the problem that driving on the floor is terrible and many solutions to the mountain destroy the tiles in the required test. Yes, This is a very tough challenge. As others have said there are many other ways to score with out going all the way up the mountain.
Our team is obsessive about climbing the mountain and have gone thru the calculations, prototyping and tested several solutions. The robot is designed. The kids have been making parts for weeks. The robot is 1/2 way assembled. Will it climb? Time will tell. Even if it doesn't. It's amazing how far these crazy 7 and 8TH graders have come. I think we accomplished the FIRST mission already.

[DavisDad]

It looks like these guys did it: FTC7837 St. Mary

[wgardner]

Originally Posted by DavisDad

It looks like these guys did it: FTC7837 St. Mary

Very nice! Interesting to note that they climbed from the mid-zone.

[Christopher149]

There's also this team.

[pilum40]

I like the use of a heavy duty tape measure. That was cool.

[Gdeaver]

Hang in right in there. Still haven't seen a team master the mountain driving.

[Nathan Pell]

How about this?

https://drive.google.com/file/d/0B1I...ew?usp=sharing

[pilum40]

where did you get the tread and the tread pads? What did you make the tread pads from? Did you 3D print the gearing system on the winch assembly? Did you 3D print the bracket or have that machined? Very curious. We've been going round and round about being required to use Tetrix gears and the extra costs that entails. We've got a robotics lab stocked with Vex...for better or worse...it's paid for. If we can use Vex parts, I can keep from charging a fee to compete this year. Please let me know on the above questions. I would appreciate it.
Thanks!

[cadandcookies]

Originally Posted by pilum40

where did you get the tread and the tread pads? What did you make the tread pads from? Did you 3D print the gearing system on the winch assembly? Did you 3D print the bracket or have that machined? Very curious. We've been going round and round about being required to use Tetrix gears and the extra costs that entails. We've got a robotics lab stocked with Vex...for better or worse...it's paid for. If we can use Vex parts, I can keep from charging a fee to compete this year. Please let me know on the above questions. I would appreciate it.
Thanks!

I can't speak for the FTC teams that have posted in this thread, but I can say that you should read the manual with regards to allowed parts-- you are certainly allowed to use almost any VEX part other than the Cortex or claw assembly-- they fall under the category of COTS parts with one degree of freedom or less.

You are not required to have anything Tetrix on your robot-- you don't have to use the motors, you don't have to use the gears, and you certainly don't have to use the metal. You can make your robot out of plywood zip tied together with the electronics duct taped on as long as you follow the relevant rules.

[polytechnique]

Our team has been able to reliably and successfully climb (6/8 times hanged in the LED qualifier in Marietta, Georgia) using a screw-drive arm system. We drive to the mid-zone, reach for the highest mountain bar, and pull ourselves onto the high mountain. As it turns out, the largest-diameter Lynxmotion sprockets allow you to catch yourself between the highest bar of the midzone and the lowest bar of the highzone, keeping your robot locked in if you have a low enough CoG.

You don't need to drive up the mountain, you can pull yourself up just as easily. I saw a lot of teams with a tape-measure system that was very flimsy, despite being compact and cool.