Acronyms are a real pain. During my time in the Air Force, I thought I'd seen every possible combination of alphabet soup. Then I came to FIRST.
There are many acronyms FTC teams should know. An important one to remember, if you're planning on using non-kit of parts (KOP) materials on your robot, is COTS.
"So an aluminum angle is a raw material, but an angle that has a set of holes pre-drilled into it by the manufacturer is a COTS," said the GDC.
COTS, or "commercial off-the-shelf", assemblies are illegal on FTC robots and the term refers to anything that is not a raw material or fastener. FTC Game Manual Part 1, 4.2.2, <R02>, spells out the specifics and includes a list of five exceptions.
The rule states "only TETRIX®, LEGO®, and/or MATRIX© preformed robotics components... may be used." The rule does leave room for creativity by allowing the use of raw materials and a select number of COTS assemblies.
According to the Game Design Committee (GDC), raw materials are extruded shapes made from any material, including plastics, metals and composites. Any material that has been formed or machined after extrusion is considered a COTS.
"So an aluminum angle is a raw material, but an angle that has a set of holes pre-drilled into it by the manufacturer is a COTS," said the GDC.
However, teams are allowed to modify raw materials as they see fit. For example, a gear purchased from a vendor is illegal, but a gear a team machines themselves from allowable materials is legal.
Items considered raw material include wood, plywood, paper and cardboard sheets. Assemblies of raw materials are considered COTS, such as aluminum honeycomb panels.
That said, the five exceptions to the no-COTS assemblies rule are as follows:
- Linear slides
- Non-motorized turntables and lazy susans
- Lead screws and threaded rod, plus compatible nuts
- Servo blocks
- #25 chain and compatible connector links and half links.
It's important for every team considering using non-KOP materials to refer to this rule and to know it well. If you have question about the rule, check the Robot Parts and Materials portion of the FTC Forum Game Q&A. This is the most popular forum topic and it's likely that another team has already encountered your situation and posed the question to the GDC. Review all the answer threads before posting a new question. The FTC GDC is composed of volunteers and answering the same questions over and over again wastes their valuable time.