Gotcha! That defense was nastier than I thought...

Earlier this week, while we were running tests with our robot, we unexpectedly had some issues going over the rough terrain… We had previously just been driving quickly over it and had no issues. However, we realized that there are going to be times when we find ourselves moving over defenses more slowly, so we were running some tests - and found that, about 20% of the time, we got into a nasty “tortuga.” :eek: Thankfully, we were able to make some minor adjustments to the skid plate and weight distribution to overcome the problem. (We were really worried, we’d have to move the bottom of the robot up 2" - which would be brutal as we are designed to go under the low bar and space is already really tight…) Still, that defense definitely proved nastier than we had expected. Anybody else have similar experiences?

For me, the number one thing would have to be the Ramparts. It was very surprising to see what happened to our robot in testing.

Another one is the Rock Wall, but I think we all knew that would be difficult to surpass.

A lot of the problems we had with them was that they busted our chains. We weren’t expecting them to be able to actually smash back against us so hard that our chains popped.

When we went and did drive testing over defenses at a practice facility, we were only able to go over the rough terrain consistently, and we could clear the moat probably 25% of the time. However, the Rock Wall and the Ramparts were too high for our drivetrain, even when going Dukes of Hazzard style crossing, so we are currently modifying our drivetrain to make it easier. But after this change, we should be good.

We had the exact same problems. We have modified our drive train to articulate on one side, and removed the front and rear frame members. How did you modify your drive train to deal with this?

So, at the moment, we have a VersaFrame style chassis with a front brace, which is being removed, and we will be replacing our drive frame 2x1 stocks, but making them one inch longer and have a cut that is angled inwards, with the front wheels moved forward so they stick out into the ‘wedge’ cut.

Its kind of hard to describe, and we haven’t finished it yet, so here’s a bad MSPaint drawing of the changes (wheels will stay on the same side of the frame, but I drew it that way so it would be evident what cut we were making)


I think our biggest surprise was when we flipped our prototype chassis upside-down by going through the low bar defense at high speed. Definitely didn’t see that coming.

Driving over the Rock Wall with our 6 inch wheels has been actually rather pleasant. The Moat and Ramparts are not as easy as most seem to think they will be.

Although we where still able to cross it, the moat has caused the most problems for 1065. We had a piece of channel on the rear of our robot that consistantly got hung up if we tried to cross slowly. In addition to removing it we found hitting the moat and ramparts at full speed the best way to prevent getting stuck.

Ramparts I get, but how much more difficult is the real-field moat from the aluminum-sheet-on-plywood team moat?

A lot of teams are testing on bare plywood

Early on in the season a student drove our prototype drive chassis over the rough terrain. He made it look so easy that I wanted to give it a try. I promptly beached the robot and damaged some of the rough terrain blocks in the process… ::ouch::

IMHO, the Moat is hard because the ramp leading up to it ends at the bottom of the vertical component of the Moat. This doesn’t give your robot time to level out before its climbing again.
YMMV :smiley:

I was really surprised with how easy the Rock Wall proved to be. Moat was surprisingly troublesome at first, but it doesn’t take much to improve moat capabilities.

Most teams won’t bother to make a complete set of defenses. I would bet many have not made all 4 of the B/D defenses. Many of the team-build defenses also have small inaccuracies- the rough terrain is the biggest offender.

The one defense that has really gotten our team was the cheval de frise. It proved to team 3711’s downfall. We were doing a test with a prototype when it went flying and made a very unsettling crash landing. That took a little time to repair.:yikes:

Team 3711: Iron Mustangs

Interesting to see the responses…has anyone actually built the drawbridge or sally port yet?

A couple of things to look at on a real field. First is the rough terrain. It is a lot rougher in real life than in wood. The sally port has the nuts that hold the skin to the frame sticking out at just around 7" FIRST has shortened the bolts from what is in the drawings, but the nuts might be tough on bumpers. Also the Port Cullis will react much different on the field than the plywood team build do, due to the materials used in the movements not being wood. In all cases the steel edges are going to act different that the wood edges on everything.