FIRST Robotics - Progress Report Six

The last two weeks of build season were hectic.  It looked for a while as if we would be done early enough to get a solid week of driving and programming practice in but that did not work out.

Some problems were anticipated.  Our "Crawler Wheels" that let us walk up the sides of obstacles were driven by a simple motor/gearbox that is part of a snowblower.  I kept expecting it to fail under the abuse.  But we just kept on crashing it into things and it kept working.  Eventually we upped the demand on it in various ways.  Finally it did stop working and just gave us a frustrated humming noise.  Open it up and you find:

We had known all along that it contained both metal and plastic gears.  This is a bad mix, as in the end metal  will always win.  Note the chewed off teeth of the white plastic gear.  Time for an upgrade:

Here our main fabricator is working on mounting the new all metal motor/gear box and associated axle.  Sparks fly.

This picture is illustrative.  The new motor is buried deep in a metal cage.  Note the solid welded steel and the "This Side Up" arrow.  We have likely gone seriously overboard on structural toughness.  To test the new front plate I hit it repeatedly with a metal bar.  This looks like something built by Klingons.

Other problems are harder to sniff out.  My son was helping out on a late season Saturday.  Peering inside the robot he noted that a bushing - a smooth metal sleeve that reduces friction - had been put on backwards and was working its way out.  This put the entire drive system at risk of catastrophic failure.  So we had to spend a precious hour and a half doing robot surgery deep in the mechanical innards of the machine.

The red stuff is gear box grease, not blood.  The small white flecks I fear are shaved off aluminum from the output shaft.  Glad we caught this before the whole thing gave out.

We have some difficult to reach areas and I do have concerns that if we must do repairs under time pressure it will not be easy.

But other than that......

We had the machine in completed state in time to take it to a practice tournament three days before the "Stop Building" date.  Here it is in the pit area on its swell new cart.  Having it up at this angle allows for transit through doors and still permits maintenance access to almost all of it.

Less so at the practice event, but at the real thing you spend a lot of time chatting with passersby. Some are just curious.  Some are FIRST officials (at this point all adult advisers take two big steps back), some are scouts from other teams.  Our visitor here looks skeptical.  To be fair, our robot is an unsophisticated tank compared to many.

Since adults are not supposed to help build the machine, and since I in any case lack noteworthy welding, machining or programming skills, it can be fairly asked just what exactly I do.  I organize stuff.  Here is our box of likely spare parts and a stuck on master guide of tools needed to repair and maintain the inner workings of the machine.

And we have tackle boxes.  Small mechanical parts.  Small pneumatic parts.  Electrical connectors.

The practice run went pretty well we thought.  Simplistic tank inspired designs do not break easily. We saw quite a few machines that day with wobbly, flimsy looking elements and yes, parts of them did break and/or fall off.  Having felt a bit guilty about how hard we pushed the kids during build season I walked around the pit area and saw about half the teams with robots that looked way shy of three days from completion.  The most elegant, sophisticated, Marvel o' Technology design can't defeat a stupid, solid metal dumbot if the former does not run.

Here is what the drivers will see at our real event.  The robot goes into mandatory storage tomorrow night.  A well earned rest for a few weeks before we start our event prep on other fronts.....