Nightmare Repairs At Competition

[BBray_T1296]

Our team had a very nerve-wracking breakdown in 2011 Logomotion at the Dallas regional.

After mitigating what we saw in the Alamo regional, we decided to add a wrist movement to our arm to allow us to pick up off the ground. Since we were already close to the 120lb mark at Alamo, we had to make light modifications, and therefore substantially weak mods compared to what we usually do.

At Alamo, we had to get tubes from the human player at the end (we had not seen the "throw the tubes" idea coming) because at the arms lowest position, the gripper was still in the frame perimeter (about 8" off the ground, above the chassis). We could only hang tubes on the 2nd level because we held the tubes straight out in front of us, like we received them from the human.

After being soundly destroyed at the Alamo, we looked at team 148's robot, and thought "we could add a wrist like that" so we could get tubes off of the ground. It would also allow us to score on the 3rd row. We had no practice bot, so we designed parts based on CAD and holding a measuring tape up to the robot on the other side of the bag.

At the Dallas regional a few weeks later, we and added a piston-powered telescopic mechanism to the top bar of our parallelogram. We then spliced a large L shaped bracket made of lightweight .040" alum between the parallelogram and the gripper to allow us to reach the ground.

It Worked! after hours and hours of Thursday work, we had a robot working great. We won most of our matches Friday and Saturday, and ended up as the #2 Seeded alliance (behind: you guessed it, team 148). They didn't pick us, they picked the #3 alliance, so we chose team 704, the #4.

But then, disaster strikes! We spent our lunch trying to touch up our autonomous code on the practice field. It would usually hang a yellow tube, but not always. Our coders were tweaking and tweaking every little bit to make it operate reliably, and it was working. As lunch started wrapping up, we deployed the fatal autonomous script, containing a typo that made the robot roll forward an extra 6 inches. Since we refuse to let changes go untested (a wise strategy) we ran it on the practice field. Our previous version left the gripper within 2" of the wall, and with the extra 6" the robot was told to go, the gripper would end up -4" from the wall.

Obviously, that cant happen, and the whole robot took the impact surprisingly well, but the robot lowered and reversed before we could react to the collision.

The gripper got ensnared from the impact on the peg it tried to hang the yellow tube on, and held fast. The arm and robot were unyielding. What happens when an unstoppable force is tied to an immovable object? The rope breaks! The light L-bracket gave, and split in 2, right as we were being called to queue for the elimination match!

In fast action, me and a few teammates flew into the pit, and attempted to get our spare l-bracket ready for mounting (it had some things attached to it). It was a fairly easy fix once it was prepped, but it took too long to prep.

In the meantime, right next to the field, our mentor and our drivers proceeded to add over 150 zipties (9") to the bracket, in a desperate attempt to make it work. They worked with panicked efficiency, looping and ziptie-gunning every last ziptie team 1296 owned.

The robot worked just fine (with the code fixed [we didn't get to test that one grr...]) and performed as it did before the damage, albeit a little more flimsy.
We lost to the #7 seed though, because both our and 704's minibots failed for 4 different reasons in the 2 matches.