Can We Reuse the Drivetrain?

I think the answer to this question is “no,” but I just want to make sure.

Can my team reuse the drivetrain we got from our Rookie kit last year on this year’s robot, or do we have to build or buy a new one? If we have to buy a new one, where from?

Thank you.

You will get another one in the Kit of Parts at your kick off event.

You cannot reuse the fully assembled drivetrain as-is legally. However, tearing it down and reusing individual components of it which have not been modified from their off the shelf form, such as wheels and motors, is legal. Parts which have been modified, such as cut frame rails, cannot be reused directly.

You will receive a new kit chassis on kickoff this year unless you opted for the Andymark Voucher instead, which could be used to purchase drivetrain components if you wish. If you don’t know what this is, you’ll be getting a new kit chassis on kickoff.

You will not be receiving a new RoboRio and certain other core control system components on kickoff, and will need to remove them from last year’s robot or buy a new one.

A new kit chassis can be purchased from here. You can also use alternative options, or try to design and build one yourself.

If the rules are the same as the past years you can reuse it if you haven’t modified it and you reassembly it after kickoff. You are probably getting a new kit bot drive base in your kit of parts this year unless your team opted out of it. If you need to buy another one they can be purchased from AndyMark.

Yeah no. Rule R14 in the Power Up manual forbids this.

Physical ROBOT elements created before Kickoff are not permitted.

There are some exceptions, such as you can make your operator console, bumpers, batteries, and some fabricated items. The fabricated items exception is so you can crimp connectors onto your motors and motor controllers.
I don’t remember these rules changing very much between seasons.

I didn’t know you could make bumpers before the season, that’s good to know. Also, responding to OP, if you were really insistent, you could technically disassemble it all the way and reassemble it, but that’s probably pointless as you are getting a new one in the KOP. I would also recommend if you are reusing certain parts, I would stay away from reusing bearings and possibly motors, depending on the purpose of the motor and your budget.

Also, I would highly recommend the Vex Versachassis system. Especially as a first non-KOP chassis, they are great. They require no real precision and you could probably put one together with a hole-saw and some careful hack-sawing. Honestly, don’t make the same mistake we did and try to custom-machine a chassis as a second-year team. I’d also like to point out that there is NOTHING wrong with the KOP drivetrain. It’s a very good chassis and no team should feel bad using it.

Saying it again for the people in the back. We don’t know the 2019 rules at this time. It would be wise to read them when they are released.

Now, FIRST has gone on record that teams are intended to reuse or source extra of control system parts (officially, the roboRIO and CTRE parts but historically we haven’t gotten enough motor controllers in the kit to power a drivetrain either). Personally, I wouldn’t go robbing any parts off an old robot until it’s necessary. You never know if you’ll need to use something old to prototype.

I wish it was legal to reuse components from previous years. Allowing teams to reuse the same drive-train multiple years would make a big improvement to most teams overall experience over the course of a season.

I know people will say that future kids would lose out on learning about what goes into designing/building that drive train, but for the teams that have the resources to take the time to do a new one every year, you could continue to. This rule change would massively help teams with not a lot of time, mentor support, money, etc. to get from kickoff to a functioning robot that much quicker and better.

I’d also be in favor of FIRST standardizing the field floor to just always being flat carpet, as this would allow those teams to work on their drive train before kickoff, giving them more time to work on the more complicated aspects of the robot during build/competition season. Again, I know people will say that this would take away the design challenges that unique obstacles/floor gives, but lets be real all these have historically done is make your average match worse to watch due to the floor of robot competence being lower with the added floor complexity. I’m pretty confident that FIRST can have games with hard enough challenges outside of requiring a unique floor/obstacle to keep all levels of teams busy.

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Does that include another chassis?

Its seems that Nick has been well and truly aFiMalated. He is advocating for the OCCRAfication of FRC.

Not a bad strategy, if the goal is a sustainable robotics program at every HS that is big enough to field a football team. I think that should be the goal.

Reasonable people can disagree. I like the Michigan model.

Back on topic: I would support a rules change (if anyone asked my opinion) to allow re-using KoP drivetrains even if the sheet metal parts have been slightly modified; e.g., by cutting to size or drilling a few holes.

Under 2018 rules (which are not necessarily 2019 rules), you can strip everything down and use, at worst, everything but the sheetmetal in a future robot and then just snag the AM14U3 Frame Only.

Even if you ignore the game design aspect of “hey, let’s use the same drivetrain over and over”, I think there’s a valid concern for new drivetrains helping to create a great team experience: maintenance. Most FRC robots go through neglect at best and hell at worst in the off-season, so dropping a whole new top part of the robot on top means you’re almost certainly sending some thrashed drivetrains (thrashed CIMs especially) into first events. And that’s if a team built their AM14U3 to the instructions; I’ve seen some Crimes Against AM14U3s™️ at events in my travels. Having a team start over on the drivetrain does ensure teams had to at least take it apart and inspect. While that takes time, I think it’s time well-spent.

(Also, I support Richard’s stance about small holes. Although I doubt anyone is policing it that tightly at events.)

Honestly, I don’t know if I agree. With the bag going away in 2020, that should make the build season at least 7-8 weeks for all teams. All teams get a full KoP chassis set in the kit with instructions for assembly. For most teams, this takes at most a day or two. For low-resource teams without proper mentorship/training, I could possibly see this taking up to a week. That still leaves 6-7 weeks to build the rest of the robot.

If not having to rebuild the kit chassis is really making that big of a difference in your season, maybe FRC isn’t the right program for you. Switching to FTC shouldn’t be seen as a downgrade for teams that consistently don’t have the resources to be competitive in FRC.

In your competition robot, without significant effort and creativity no, but you know what it is really good for?


Even if you do not build a fully functional practice bot, just having a rectangle with wheels that you can stick stuff on and push around to try out things like intakes and the like can be super helpful. (you can also use it to play a little defense during practice, or at least park it in the way)

Physical ROBOT elements created before Kickoff are not permitted.

Any opinions on where the line is with this sort of thing? For example, if we take a piece of aluminum square tube off last year’s robot and cut it in half during the build season, can we use it on this year’s robot? I would think yes. What if we cut it down by 1/8"? Drilled a hole? Filed an edge?

The general consensus is that it’s not allowed to use a part cut to a final dimension, but it’s okay if the part is cut for storage purposes. So if you order 60" lengths of tubing and cut it into 3x 20" lengths to store, that’s fine. If you cut it into 8x 6" lengths because you need 6" lengths of tube for your chassis, that’s not okay.

If you drill or file the tube (or any other part) to make specific features that will be used on the robot, that’s not okay. (e.g. drilling a bolt hole, filing a notch for clearance) If you file off a rough edge to make it safer to handle in storage, that’s probably fine.

So if you take a tube with specifically drilled holes off an old robot, cut off 1/8", and use that tube again, that’s not okay since the holes were made as a final dimension. If you had an unmodified (other than custom length) tube on an old robot, IMO you can cut it to a new custom length and use it again. If you had a KoP chassis rail cut to custom length but not otherwise modified, if you then cut it down further to a new custom length you should be able to use it since the rail was only modified pre-kickoff for storage (being stored on the old robot).

At the end of the day, this all comes down to the honor system. The likelihood is that no one will catch it if you mess up on the intricacies of the rule, especially if it’s something rather trivial like using a tube from an old robot with a hole drilled in it.

I’m fully on-board with loosening the restrictions on using components fabricated before kickoff. I think it’s something that can tremendously help the bottom teams in terms of not only scheduling, but also cost control. We encourage recycling in about every other walk of life, we should allow it much more in FRC. It would enable more teams to select the AndyMark drivetrain voucher, for instance.
It would also help us sidestep semantic issues like the ones discussed in the previous couple posts to this. Take a piece of metal with a couple holes in it from an old robot doesn’t really give an advantage other than very mild savings material/costs, but it’s currently not allowed by a strict reading of prior years’ game manuals. I don’t see any reason we should bar teams from re-using that piece of 80/20 that they tapped an end of last year.

Not sure I’m on-board with this change. I agree that FIRST could often do better in balancing the “engineering challenge” vs. “gameplay experience” knob in terms of game design (limited field vision sucks!), but I’m not sure I’d dial it so far over as to remove driving obstacles. It may be my own personal biases speaking, but I love the engineering challenge of designing a robot to interact with field obstacles. I got hooked on drivetrain design as a student in FRC, and have carried that passion with me. There’s an awful lot of people who get as inspired by the build season portion of this program than the competition season portion. I would hate to dial away from the engineering challenge too far.

This is kind of a side point but I expect wire conduit on the floor to be more common in the future. There seems to be a push for more lights and more scoring automation on the game elements on the field. Conduit taped to the floor is the easy routing method.

This is an interesting topic. I’m probably more in favor of keeping the field mostly flat every year, but I can see the appeal of having some obstacles to shake things up and spur interesting designs. I do think it’s a problem if the kit drive has a hard time playing the game. The level of difficulty of getting past an obstacle should be designed carefully to make the game work as well as possible for the community as a whole. Also, the reward for being able to get over the obstacle and the penalty for not being able to so shouldn’t be too enormous. Stuck robots aren’t as much fun. I like a game design where you can go around the slow way to avoid an obstacle. That way teams can design according to the realities of their own resources.

Everything else aside, I prefer flat fields so we don’t have to build and store balancing bridges, castle defenses, bumpy soccer bumps, and so on. You know what game was cool? Aerial Assist. Our team didn’t build a single field element for that game, and we got to make a fast robot, and life was pretty good.

Want to point out a couple of things:
To start off with, most FRC teams are low resource teams.
Second, when you say it takes a week to build, I assume you mean 3-5 days.
For most low-resource teams this means 2-3 weeks of the build season.

This isn’t even a possibility in Michigan, for example.
In Michigan, FRC is for high schoolers and FTC is for middle schoolers.

I don’t think gatekeeping like this helps the program at all.