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RC Burglars - Archimedes Playoffs
We've all done the math. Recycle Containers (RCs) were the key to scoring big in Recycle Rush, and an alliance of solid stackers would win if they were able to control the majority of RCs on the step at the match start. This made a fast RC Burglar which grabbed RCs at the very start of autonomous an essential accessory for a victory-seeking robot.

Autonomous Strategies

A quick scoring analysis makes the value of RCs glaringly obvious. If two alliances of competent stackers face each other, the alliance which is able to gain control of the majority of the Step RCs will almost certainly win the match. It's also obvious that the time to gain control of the Step RCs is at the very start of the match; the first second of autonomous period.

In a highly competitive match, two autonomous strategies make sense:

  1. Fast Can (RC) Burglaring. A robot should secure two RCs from the step during the first second or so of autonomous. In a highly competitive match, it should be assumed that all step RC will be controlled by one alliance or the other during the first second (or so) of the match.
  2. 3-Tote Autonomous. This is the only autonomous routine which will score points (and significant points at that) during autonomous without reliance on alliance partners

An ideal alliance in a competitive match would comprise two robots having fast double RC Burglars and one robot with reliable 3-Tote Autonomous.

RC Burglar Design

RC Burglar Hook
Two RC Burglars were mounted, one each on the left and right sides of the robot with pivot points close to the front corners. The axes of actuation diverged outward from the robot centerline, allowing the burglars to engage the center holes of either the left or right two Step RCs.

The RC Burglars work by extending to engage the RCs with the robot in the starting position (just outside the landfill). After the RC Burglars engage, the robot then drives backwards to pull the RCs off of the step and over the landfill. RCs end up on their sides.

The main element of each RC Burglar is a 63.5" long 0.840"OD x 0.750"ID carbon fiber tube with aluminum clevises glued and swaged into both ends. The bottom clevis engages a bushing block via a 3/8" pin. The bushing block is mounted to the chassis. The top clevis engages a fiberglass rod hook via a 1/4" pin. The fiberglass rod hook directly engages the RC via the top hole. Two additional fiberglass rods are lashed to the fiberglass hook to stiffen the hook structurally and reduce the hook flexure upon
RC Burglar Mount
striking the RC. By reducing flexure, the bounce is reduced and therefore time before driving backwards also reduced.

The RC Burglar is extended by extending a 1-1/16" pneumatic cylinder. The cylinder rod is secured to the carbon fiber tube via a machined aluminum clamp. The cylinder extension is assisted by a latex tubing tension spring.

A 1/8" nylon cord runs from the back end of the fiberglass hook to the rear pivot of the 1-1/16" pneumatic cylinder. When the RC Burglar is extended, this cord extends the fiberglass hook so that it engages the RC. A 1/8" latex cord spring on the opposite side of the fiberglass hook pivot prevents the hook from bouncing over 78" when the RC burglar is retracted.

Development Timing

We always understood that RC Burglars would be important in competitive play, but we did not think we would need them until MAR Championship because the level of competition in the district qualifiers would not require them. This allowed us to focus on getting the stacking working reliably and quickly as a first priority. We turned out to be right about this. 1640's RC Burglars debuted at MAR Championship; just in time.

An improved version was used at FRC Championship, allowing faster burgling.