Go to Post If your prototype works perfectly, you've been working on it too long. - Blair Frank [more]
Home
Go Back   Chief Delphi > FIRST > General Forum
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
 
 
Thread Tools Rate Thread Display Modes
Prev Previous Post   Next Post Next
  #13   Spotlight this post!  
Unread 28-03-2013, 16:37
Chris Hibner's Avatar Unsung FIRST Hero
Chris Hibner Chris Hibner is offline
Eschewing Obfuscation Since 1990
AKA: Lars Kamen's Roadie
FRC #0051 (Wings of Fire)
Team Role: Engineer
 
Join Date: May 2001
Rookie Year: 1997
Location: Canton, MI
Posts: 1,488
Chris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond repute
Re: Nightmare Repairs At Competition

This story has given me nightmares ever since it happened.

It was 2002 on Einstein, the last year at Disney. I was the field coach for 308 (The Monsters) back then and our alliance of 180 (SPAM) and 311 from Islip, NY made it out of our division after some rough matches.

Back in those days the matches were 2 vs 2, but the alliances had 3 robots. You had to play all three robots in each round in order to advance. The typical strategy was to have one robot be your anchor and the other two robots would swap. Our robot was the anchor of our alliance as we had the ability to quickly grab two of the goal and then lift them up to transfer the weight of each goal (at 180 lb each, if I remember correctly) to our robot. We could basically drive wherever we wanted once we had the goals lifted. We had a third arm to grab the last goal which would basically ensure us the win.

We were able to win the first round on Einstein in two straight matches agains a great alliance of 118 (Robonauts), 233 (Pink), and I want to say 144 (Who?), but I'm not sure about the third. It was on to the final round for the world championship!

The finals were set once 71 (The Beatty Beast), 173 (RAGE), and 66 (the Penguins back in those days) advanced in two straight in their semi-final. It was going to be epic. Team 71 seemed to be unbeatable, be we thought that we could lift the goals high enough to lift their robot's file cards off the ground (one last trick up our sleeve that we haven't shown yet). I couldn't wait.

Then, the nightmare occurred.

One gear in the gearbox on the left side of our drive train started to shift so there was only about 50% of the face-width engaged, and we didn't see it. The match started and we raced to the center of the field to meet 71 at the goals. A big collision occurred, and every tooth from the gear box in that reduction stage sheared off. We were useless as the left side of our drivetrain could transfer no torque. Needless to say, we lost that match.

In match two, SPAM and 311 went in while our pit crew tried to see if we could make a fix. In the 2nd match, SPAM and 71 had an even bigger collision at the center goal causing 71's goal grappler to break. SPAM and 311 were able to manipulate the goals with enough authority to win match 2.

One match for all the marbles...

Our pit crew couldn't replace the gear in time. However, since the gear had shifted to having 50% of the facewidth engaged, only 50% of each tooth sheared off (we were using aluminum gears to save weight). The pit crew pounded the shaft over so that the remaining teeth were engaged. The drivetrain ran, but I knew it wouldn't stand up to another collision with 71. When it came time to pick who was going to play and 311 (our alliance captain) asked if we could go, I told him that 311 and 180 won the last match, they should try it again.

Then, the 2nd nightmare occurred: 71 took themself out of the match, leaving 66 and 173 to play. 66 had plenty of torque, but they were a single speed robot. We had a high gear (about 10 ft/s to race to the goals), and an ultra low gear (about 1.5 ft/s for push once we got the goals lifted). I KNEW we could be 66 to the goals, get them lifted, and the match would be over. I ran to 311 and told them we could go against 66, but it was too late. The referees said that we had already submitted our two robots to the match.

Needless to say, 173/71/66 won the match and I've never came that close to being on a world championship team.

I tried to convince myself that "maybe the half-sheard gearbox wouldn't have even been able to drive." When we finally got the robot home, we just had to set it on the field and see what might have been. The robot raced to the goals, lifted them, shifted to low, and was able to push them into another robot with no problem. Oh what might have been. I've been haunted by that ever since.

I have pictures of that gearbox that were taken immediately after that first match ended. I'll have to see if I can find them.

Edit: I found the pics. Here's one of them:

__________________
-
An ounce of perception is worth a pound of obscure.

Last edited by Chris Hibner : 28-03-2013 at 18:53.
Reply With Quote
 


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 11:31.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi