[FRC Blog] The ShREK

FIRST General Forum
#1

Posted on the FRC Blog, 2/24/17: http://www.firstinspires.org/robotics/frc/blog/2017-the-ShREK

The ShREK

Written by Frank Merrick and Andy Baker, 2017 FEB 24.

From Frank:

For things that must be done, it’s always a good idea to have a ‘Plan B’. With FIRST STEAMWORKS, the field must be able to count the fuel being scored in the boiler. And while we have confidence in our equipment being able to handle that very well, things happen.

We call the unit inside the boiler that sorts the fuel into a single chain that can be counted the ‘serializer’. Of course events will have spares for all the key components (motors, power supplies, etc) within the serializer, but if one of those complete pre-assembled units falls off a truck, or gets speared with a forklift, it may be more than can be fixed easily at an event.

FIRST realized both that:

  1. We needed a Plan B.
  2.    We had no resources available to create one, as we’re all working away on our many ‘Plan As’.

So, we turned to our friends at AndyMark and said “little help?” Of course, AndyMark has been a generous (Crown Level) Supplier, and has helped us with major projects before (have you heard of FIRST Choice?), but in addition to that, AndyMark has a bunch of FIRST Technical Advisors (FTAs) on their staff. The combination of their experience at events plus the fact that their staff may need to actually implement Plan B made turning to them seem like a no brainer. We gave them the outline of what we were trying to do, and as they have done in the past, they took this task on with gusto. The result was ‘The ShREK’, the Serializer Replacement Emergency Kit, which will be made available to all events should something very serious and unexpected happen.

We want to thank AndyMark, once again, for being a true friend and partner to FIRST and our teams!

From Andy:

We at AndyMark are happy to help create a solution which hopefully will not be used at any events. Ideally, all of FIRST’s serializers will be shipped and handled without incident. But, in the rare case that a serializer is hit by a meteorite or drops into a sink hole, we have a solution. We have been able to cut polycarbonate sheets and attach them with zip ties to a Boiler for a simple solution which can help keep a FIRST Robotics Competition event running well. These sheets combine with a ball agitator, driven with a corded drill in order to keep a steady flow of Fuel out of the Boiler at a rate of 2 balls/second. We are looking forward to not using this solution at any of this spring’s events, but happy to be able to provide this fix. Here we see AndyMark engineer, Nathan, with a cordless drill, some aluminum churro, a bracket, and some agitation magic. AndyMark will be providing this insurance packet of polycarb plates (5 per boiler), the churro, and the bracket to each field.

http://www.firstinspires.org/sites/default/files/uploads/frc/Blog/ShrekDrill.gif

#2

Bet we see these at off-seasons later on in place of the serializers…

#3

2 Balls a second? At IRI? No way.

#4

While I like the preemptive and cautionary movement to make sure the game doesn’t get broken. This replacement breaks the game itself in not being able to reach the 5 balls/sec that teams are planning for. I understand that this is the back ups back up but it would suck to lose a competition because of this.

#5

Nobody said you only had to use one at a time…

#6

Hosts of events could probably build their own counters that can go faster then 2bps… I mean teams are shooting much much faster then the official serialize using only one shooter, same concept.

#7

In keeping with this years’ theme, I hereby declare that the volunteer who unjams the boiler shall be referred to as the chimneysweep.

#8

Does using this back up make 40kpa autonomous modes impossible? How do the balls get counted/returned to the bins via this system?

-Mike

#9

Hear, hear!

#10

I really hope that if an event is forced to use these they pause the match between auto and teleop.

#11

At 2 balls a second it seems that way. If the serializer is broken in a past match 40 kpa auto is impossible.

#12

Replacing the rigid end on that drill with some flaps of surgical tubing/rubber/tread whatever and spinning in high (1000-1500 rpm) will improve the flowrate out of that substantially.

#13

Certainly hope that if one of these has to be employed, the other boiler will also receive one. If not, the alliance with the working ball sorter has a MASSIVE advantage.

#14

“WHAT ARE YE DOIN’ IN MY BOILER”
https://i.imgur.com/x010CpV.jpg

#15

I knew all games involving ball shooters would have pokey sticks.

#16

What if teams brought backup serializers? If a team could build one that doesn’t go faster then the stated 5bps average that the regualr one is advertised as, I think everyone at the event would prefer that over this current backup.

I doubt FIRST would approve of its use at an event, but is it worth a try?

#17

Sean’s axiom: All games with ball shooters will have pokey sticks.

#18

I feel that this replacement differs enough from the original that big aspects of the game strategy will need to change if it enters a match. If this comes into play, 40 kPa autos are gone, teams will need to shoot their final salvos way before time runs out, and strong fueling robots will need to always be wary of boiler overflow.

I do wonder how does this design interfaces with the FMS? Will the field know which fuel is scored in auto and which is scored in teleop? Will the ShREK operator be responsible for stopping their processing at the end of the match, or will this be automated? Will balls enter the bins in the same way as before?

All being said, I applaud FIRST for admitting that the boiler may have issues and for taking to the time to develop a backup. While this solution is not optimal, its way better than having an event go fuel-less or engineering a solution on the spot.

#19

Somebody once told me the drill was gonna poke me

#20

It looks like it still goes through the counter in the 1 ball wide tube that attaches to the hole in the back, just without the fancy rotary sorter.

It will certainly affect the 40kpa auto at 2 balls per second outflow in one fashion or another. Either they extend the disable between auto and teleop and allow all balls that entered the boiler during auto to be counted (eg, more balls count than per rules spec) or they still cut off the count at whatever has been processed at T=0, which means that it can process a maximum of 30 balls (nominally) in the 15 second auto.

Honestly, it would affect more than just 40kpa autos. At a processing rate that slow, it’s likely that multiple 10 ball autos on an alliance won’t have all of their balls counted if they still cut off counting at T=0, especially if they don’t start shooting right when auto starts (like after dropping a gear off).

Needless to say, this is a) concerning and b) needs a defined protocol for how they handle this situation. I agree with the above sentiments that if one boiler has to be ShREK’d, both should be for consistency.

I’m happy they are thinking of a backup plan. My vote would be to hold teleop disable until all balls are counted, like 2006. That eliminates the possibility that the human now charged with running the drill doesn’t start right away, lifts his/her hand off the trigger, gets distracted and forgets to run for the whole period, or the drill battery runs out. Take the human factor out as much as possible and everyone will feel a lot better.