Never Do This, and Other Good Ideas Gone Bad

[JamesCH95]

Originally Posted by Dillon Carey

2010: do not put a bearing on a hard anodized shaft.

At Midwest we lost due to our chain falling off. Don't cantilever a swerve module off of a hard anodized aluminum/needle bearing combo.

(This doesn't mean we will never try these types of systems again. These are just examples of poor implementation.)

For what it's worth: anodizing makes the surface very hard. Anodized aluminum is much more susceptible to fatigue cracking, further shortening the life of a metal that already has a short fatigue life. IMHO anodizing, hard anodizing especially, should not be used unless wear is of concern.

[Hawiian Cadder]

home brew milti speed transmissions, dewalt or andymark only


anything with more than 150 ft lbs of torque

[AdamHeard]

Originally Posted by Hawiian Cadder

home brew milti speed transmissions, dewalt or andymark only


anything with more than 150 ft lbs of torque

Many teams have done both without issue.

I think a more general rule would be; don't reach beyond your team's means.

[Brandon Holley]

Originally Posted by AdamHeard

Many teams have done both without issue.

I think a more general rule would be; don't reach beyond your team's means.

Totally agree. I've done custom tranny's with no issues as well. It's definitely a don't reach beyond your capability issue.

-Brando

[EricS-Team180]

Don't use a limit switch in place of a hard stop. T'was the end of our 2005 season, when we launched out tetra lift clear off the robot.

[JamesCH95]

Originally Posted by EricS-Team180

Don't use a limit switch in place of a hard stop. T'was the end of our 2005 season, when we launched out tetra lift clear off the robot.

Don't run two FP motors through a Dewalt transmission with an extra stage of reduction and expect the output shaft to survive an encounter with said hard stop. Ever seen a case-hardened Thomson steel shaft snap like a twig? Out 2005 experience with hard-stops and failing limit switches.

[Neil2012]

I have a few things that teams should avoid. First of all, catapults. In 2008, I designed one for our team, but the execution of the design was poor and the end effector team couldn't find anything that would pick up the balls well. Also, avoid linkage arms. In 2010, I yet again designed a 12 bar linkage for our team and, even though it performed to specifications, the work that has to go into making the lengths right so that it can extend to 7 feet and still fold up flat, is monumental. You can do it with math, but the equations are way too complicated for anyone at the high school level.

[Aussie Oi!]

I think that you should only do ideas that you know that work, and only do other ideas if you have been dong FRc for many yours or you know what you are doing!!!!!!!!!!!!!!!

[tomy]

our team decided to get more batteries last year. we had to make our own cable connectors to from the battery to the robot. DO NOT MIX UP BLACK AND RED!!!! you can fry your crio. it was a great idea but not so great at the same time

[klmx30302]

our dont ever do agains from last season.
NEVER speend 2 weeks argueing over the design of the robot.
NEVER just give software 6 hours with the robot.
NEVER use belt drive.
NEVER repeat last years robot (we overloaded our jags every time we turned!).

[MattC9]

Doing swerve before prototyping in the summer 'nuff said

[TD912]

Pneumatics can be useful, but don't make your whole robot run on it.

In 2010 we relied wayyy too much on pneumatics. Our kicker, hanger, and "special" drivetrain (see the link in my sig) all used pneumatics. We always were worrying about running low on air, even with the onboard compressor and 4 accumulator tanks.

[apalrd]

Originally Posted by TD912

We always were worrying about running low on air, even with the onboard compressor and 4 accumulator tanks.

Did you ever actually run low on air? Probably not.

We built some stuff this off-season that relied on pneumatics, and fully automated it (in C on an IFI processor). The automation was very rudimentary and would actuate a lot (if it was on the threshold it would switch very fast). We used a mini-pump (a tiny red air pump, similar to the one this year but with less output) and 1 tank, and set the tank pressure switch to about 100psi (the pump struggled to go past that). It ran fine, and we ran it hard. So hard that the pump eventually overheated and seized, and only then did we run out of air. When we put in the old pump, it ran fine indefinitely (well, until the battery died).

[Andrew Schreiber]

Originally Posted by apalrd

Did you ever actually run low on air? Probably not.

397's original bot in 2008 relied on pneumatics to hurdle the ball, the way the old system was set up we had to run a lap while the tanks refilled. We fixed that during the off season by changing the geometry of the launcher. So, yes, I've run short on air numerous times.

[thefro526]

On the subject of Pneumatics:

One cycle of a 2" Bore, 24" throw piston at 60 psi uses the entire legal air storage capacity of a 2005-2010 FRC robot.... We tried to use one for hanging last year, without realizing that we wouldn't be able to use our kicker for approximately 15-20 seconds before firing the hanging piston or else we wouldn't have enough air at the end of the match to hang.

(A cycle being, piston extended and then retracted.)