[jvriezen]

I may be biased based on what we did, but from what I've seen, for speed and reliability, the best approaches include one or more of the following:

1) Some type of alignment that uses the tower base as a reference (e.g. a fold down plate with a tower base radius matching cutout) This is not essential however, if item (3) is done well. (This is the only item in this list we did not do, but still had pretty good deployment success.)

2) A center mounted slide mechanism, pre-loaded with surgical tubing, and released with pneumatics or servo. We used two drawer slides and one igus slide, with two stages of tubing. Be sure to keep safety in mind -- we put a safety strap (removed just after placing the bot on the field) and also had a red danger flag that we put on the robot when transporting it to help keep people from walking too close behind. For the longer drawer slides, we looped the tubing back and forth to have a greater overall length. In other words, it works better if the tubing goes from 30" to 10" in deployment rather than from 12" to 2".

3) A pivoting V/funnel plate that will help with finer alignment. Ours was integrated with the surgical tubing slider mechanism so that the same laterally mounted surg tubes kept the V centered (until the pole persuaded it otherwise) and also provided slider thrust when released. The plate cutout had a shallow V, but at the vertex of the V, we cut back a rectangular slot, a bit wider than the pole, so that the last bit of travel was straight in line with MB, avoiding an angled approach of the minibot. That's the 'funnel' part of the plate.

4) Minibot mounted with tube/pin interface (at least 2). Probably doesn't matter which bot (HB or MB) has tube and which has pins.

5) Locking pin to prevent MB movement prior to deploy. We used a horizontal pin that went thru a hole in the mounting tube and vertical pin which held MB in place. It had some friction fit, so that it wouldn't jostle loose. The horizontal pin was attached by a string so that the pin would be pulled out just prior to MB reaching the pole. Just gather up the slack in the string with a loosely fastened zip tie so that the string doesn't get caught in something during the match.

5) Turn on power to MB before it reaches pole -- we used a simple string with a loop on the end to pull a standard wall switch on the MB.

6) Software control that releases the MB only when two things are true: a) Driver is pressing deploy button b) Match clock reads <= 10 seconds. Some have told us (b) was risky, as the internal cRio match clock might not be synced exactly with field clock, but we were never called for early deploy.
You mileage may vary. This way we lined up, held the deploy button and as soon as clock hit 10, it goes.


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Other good ideas involve a two step deployment, where alignment and contact with the pole happens prior to 10sec, and then the MB rides a rail out the pole at 10sec mark. But this seems more complex and takes more time if you are late to the tower due to being defended.


John Vriezen
Team 2530 "Inconceivable"
Mentor, Drive Coach, Inspector