Your theory vs. your capability

[Petey]

Now that your robot is (hopefully) built and tested (to some degree), how well is your design standing up to reality? Is your CG that solid? Your tetra grabber that fast?

Vote, and qualify.

I'll start. Turns out one of our articulated arms motors isn't quite strong enough to lift what it needs to lift in a certain degree range, but we've managed to compensate for that by keeping it out of that degree range using an almost-as-effective pattern of arm movement.


Our CG is pretty solid; we're underweight; and it looks pretty good.

--Petey

[sanddrag]

The drivetrain is a little louder than expected but should still be a quite solid performer, just as it was designed to be. We are not getting as many shifts out of the air tanks as we expected, but even if you shift ten times per match that is like every 12 seconds. We should not need more than six shifts in a match. The arm is absolutely amazing. Speed is as designed, but length, movement and reach is much more impressive in person than in Inventor. Through about four hours of practicing yesterday, we have found that the whole process of obtaining and stacking a tetra takes a very significant amount of time, but hopefully with more practice, programming, and a few mechanical tweaks that will speed up. For weight we were .25-.5 lbs over, by the end of tonight we will be under.

[AJunx]

Our robot has run head-on into a number of real world issues. The main problem right now is weight. The robot is overweight because key parts (parts that hold stacks of tetras) had to be reinforced.

Once we figure out the weight issue, it looks like our robot will be able to accomplish what we originally set out to do.

[russell]

Yeah, our robot ran into a few issues too. The smallest issue it quite litterally ran into was a wall. Bigger issues it (somehwat less litterally) ran into were the tetra grabber being clunky and not working that well, and the arm actuation being less than perfect. Overall better than last year though.

[Denman]

we are good, except after testing we found a couple of situations where we can freeze the robot completely (ie tetra gets stuck on the lifter arm behind the lifter and can't get off

[Rick TYler]

Our robot exceeded my expectations in every way. It was under weight and worked better than I expected. We even survived having another 'bot shove its tetra spike right through our grabber mechanism.

* Loading tetras takes longer than I thought it would.
* Scoring is faster.
* Our 'bot is much more maneuverable than I expected.
* Our fairly short arm stacks much faster than some teams with long arms.
* Our mechanism appears to be bullet-proof, as we went through a couple of hours of driving on Saturday without a failure (this is what you get by allowing a 4x safety factor on your torque calculations).
* In a real match with six robots, I think it will be hard to score more than 3-4 tetras per 'bot, even without much defense going on.
* Our positive-grip tetra holder has some real advantages over passive holders.

I am so looking forward to Portland.

[Gene F]

This has been a strange year. Following are some of the reasons:
Every time we weighed our bot is was just barely under weight.
What we said we would build and what we built are the same.
We only had to design one electronics layout (normally 2 or 3).

I'm not saying that there were no issues, that's not reality, but we were able to overcome them without major redesign.

[Petey]

Originally Posted by Rick TYler

* Our mechanism appears to be bullet-proof, as we went through a couple of hours of driving on Saturday without a failure (this is what you get by allowing a 4x safety factor on your torque calculations).
.

Lucky you.

We allowed a 20% margin of error on one joint of the arm and it turned out to still be too weak.



I think we worked a fix though.

--Petey

[Sachiel7]

Our robot turned out to be everything we set out for it to be - a fast, precise (well, to a degree) tetra capper that can play both offence and defence. We had one issue with our manipulatr design, but other than that everything has turned out great. The transition from CAD to the "flesh" was probably within a 99% accuracy rate. Everything mechanically is performing just as intended.
So far, so good!