Nightmare Repairs At Competition

I prefer the BLOK-LOC clips for this.

During Week 6 at the Pine Tree Regional after two days of no hiccups with our autonomous 30 point climber our team struck horror in the quarterfinals.

During qf1.1 when our team went to climb at 30 seconds left in the game we lifted to level one just fine but our arm that lifts the hooks to the second bar stayed on bar one without rising to level two. Our team tested the system in our pit and it worked fine. We did however find a lose power connection to our climber and a questionable battery. Problem was assumed as a power issue.

During qf1.2 the same problem happened as the arm still wouldn’t move from level one. We noticed our cable was unspooled meaning the arm should have been expanded but it was jammed on the bar. Back in the pits we noticed our pawls had come loose so when we hung the hooks became jammed on the bar due to the pawls being crooked. All caused by a collision in qf1.1.

Our team tightened everything down and ran to the practice field to test climbing. The arm worked fine but the winch was out of whack. As our team was getting qued for the semis we noticed our encoder had been knocked out of alignment and damaged. What ensued was the scariest 15 minutes of the weekend as both the competition and practice climber were taken apart to switch encoders. Thankfully one of the quarter finals went to 3 matches giving us some more time for surgery.

Once the new encoder was on we had no issues for the semis and finals!

That’s nice, I like that.
Thanks!

Agreed, I had not seen those before! Thanks for the info!

We were going through inspection and had most everything checked off and then one of judges takes a closer look at our robot and says that we used a larger wire gauge. So our entire robot had to be rewired, putting all other work to halt while the electrical team scrambled to fix everything. Then of course there was the rapid swiss cheesing and filing of the corners. We ended up passing inspection moments before our first match (and here I will point out that we are a rookie team and we had the first match of the day) at exactly 120.0 pounds.

Also, please excuse my ignorance, but what happened to teams 1592 and 801?

I hope this is just a glitch in terminology, and not a description of an inspector requiring you to replace oversized wire with something smaller. The rules don’t specify the required wire gauge for each branch circuit, just the minimum size of wire based on the breaker protecting it.

The confusion is that smaller size wire has a higher gauge number, and larger size wire has a lower gauge number. Saying “larger gauge” is mixing size and number descriptions.

This thread should help.
http://www.chiefdelphi.com/forums/showthread.php?t=114724&highlight=1592+801

at 2370, our tradition is to have the pit crew travel to the competition on wednesday for load in, the rest of the team arriving during practice day. We arrived at WPI for the 2012 game eager to see what our tank of a robot (affectionately named OverKill) could do on the field. Everything was going well right up until inspection time…
Our robot weighed 20 pounds over the limit. When the rest of the team (myself included) walked in around lunch, we came to see the robot not in the tank-like form we knew and loved with its 10 inch wheels for height over the mid-field bump, but rather came to see a machine that looked something akin to a truck with prius tires installed. We had to drop down to 6 inch wheels, and got so desperate to shed weight we ended up ditching one of the polycarb protection panels in favor of mesh netting. our robot played well, but it wasn’t the same monster we dreamed of seeing on the field…

Our shooter motors and their controllers kept going out. Maybe using BAG motors for powering a shooter is a bad idea. We went through many motors and we were still easily crippled at any time during the competition.

2012 was an interesting year

After rereading the first post in this topic I think the additional take away:

Less running more Segway.
If only we knew someone with access to Segway :slight_smile:

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.


gripper 2.jpg




gripper 2.jpg

I don’t have the video link handy, but at the 2013 MAR CMP, Team 75 was at the 30 point level…and fell off. The robot turned exactly upside down when it hit. Bounced a few inches, then fell over.

The entire crowd went :ahh: Then silence for a few seconds. During a match.

Back at the pits, virtually every team was there asking if they could help. A sawzall was found to cut the 1/2" tool-steel shaft that was bent into a U away so they could get at the damage.

Long story short (They’ll have to tell you the long version) with a lot of help from several teams, they made it onto the field for their next match, 100% repaired. The crowd went wild.

I do remember something similar happening on the Mt Olive practice field. They did get it back running in time for qualification matches