Should Individual Motor Quantity Limits Return?

Rather than outright “banning” Falcon 500s and Neos, is it time that FRC brought back the limits on the quantities of each motor that can be used on a robot? For most of FRC history, limits have been in place on how many of each motor (or grouping of motors) could be used. For a long while, every single motor had a maximum quantity associated with it. But the most notable restriction was on the quantity of CIMs used (as, for a long time, they were essentially the “gold standard” of FRC-legal motors). When CIMs were first introduced (2003?), teams were limited to 2 CIMs on their robot. That raised to 4 CIMs in 2005, and to 6 CIMs in 2013. In 2016 & 2017, CIMs were the only motors with quantity restrictions. And in 2018, the quantity restrictions were dropped entirely (just before the arrival of the Neo in 2019).

With the continued addition of high-powered brushed and brushless motors to the FRC toolbox, as well as improvements to smart speed controllers (current limiting and motion profiling being chief among them), and the availability of less restrictive electronics systems - the FRC ecosystem has changed dramatically in the past few years since the restrictions on motor quantities have been removed. As has the FRC vendor ecosystem, as the entire world’s supply chains. While limitations on motors certainly wouldn’t solve supply chain issues with other high demand COTS products, it doesn’t mean it’s not worth exploring. Would bringing back some form of motor quantity restrictions be beneficial to FRC?

Here are some potential impacts I could see from restoring some level of limitations on motor quantity:

  • De-incentive high resource teams from bulk ordering limited quantity motors (and associated speed controllers)
  • Potentially allow for the current allocation of these limited quantity motors to be spread across more teams
  • Incentivize the use of (relatively) high powered brushed motor options (775 Pros, CIMs, MiniCIMs, Bag motors) that teams may already have stockpiles of
  • Incentivize the use of speed controllers designed for brushed motors, that teams may already have stockpiles of
  • Incentivize high-powered teams to explore power-take-off (PTO) mechanisms for high-load (presumably endgame) tasks
  • Potentially screw with COTS vendor quantity estimates (or material orders) if changes to this rule are made too close to the start of build season
  • Potentially incentivize the use of mixed ecosystems of electronics (if REV and CTRE/VEX brushless options are not placed under the same quantity restrictions)
  • Restore a design trade-off associated with motor allocation to the FRC design challenge
  • Potentially reduce the implicit design penalty on teams associated with continuing to use the CTRE PDP instead of the REV PDH (given the REV PDH’s increased number of 40A breaker slots)
  • Potentially incentivize the use of pneumatic actuators (depending on game design)
  • Potentially increase demand for products aimed at adapting 500 or 700-series motors to CIM mounting patterns/free speeds for use in COTS products designed to accept CIM-style motors.

What say you, Chief Delphi? Would limiting teams to only using, say 6 or 8, high powered brushless motors improve the FRC ecosystem?

6 Likes

No thanks.

Motor Limits?
  • Yes
  • No

0 voters

8 Likes

This alone is why we need a brushless CIM limit next year. Redistributing the stock teams already have could singlehandedly mitigate the stock issues, never mind the reduced need to buy more motors. FIRST could even run a buyback program of sorts to streamline this process.

Hopefully, this would only have to be a temporary rule. I don’t think keeping it around if stock stabilizes will solve much of anything, unless you’re a big fan of 775pros or something.

5 Likes

downloadfile

23 Likes

If there are motor limits, there should be an exception so using 40 bag motors is still allowed.

14 Likes

My general proposal would be no more than 6 of any given motor. Apply to all motors (or a subset, the CIM-size motors) this year, and going forwards any motor being introduced would be subject to that rule in its first season. If there’s supply-chain issues then target at any motor that is having issues.

I’d be OK with that number being 8 instead of 6. I’m not sure the carpets will be, though…

7 Likes

Restricting single motor quantities would effectively eliminate Falcon spam, which seems to be popular at the moment. Innovative solutions pretty much only come about with a relative limitation, motors like the Neo and Falcon remove almost all motor centric problems as they are powerful, controllable at a range of speeds and have smart and accurate control systems with encoders.

Limiting motor types would produce more unique solutions to problems, but at a performance cost. If this is across the board, I don’t think that’s a problem though. It also reduces the advantage of having 80 falcons available to a team vs 8, if say a limit of 8 per robot is enacted. If nothing else, a robot covered in varying motor types and solutions to use them is far more interesting and impressive in my eyes.

One more advantage of say having all Neos on a robot is simplifying repair and spares kits. Though again, if everyone is in the same boat then it reduces the advantage of a team being able to afford a pile of the same high performance motor over a less resources one that has a varied kit they’ve collected over the years, while providing additional challange and design considerations. But with the trend towards more performant robots at all costs, the more brushless the better. I think a motor count limitation is a good idea, but would mean many team’s robots will not perform quite as well as they otherwise would have, which is a loss.

2 Likes

Just because you limit the number of motors allowed on one robot: does not necessarily mean a team can’t order 50 motors, but only field 6.

This is as much a business economics issue as a technical issue.

Most people are suggesting controls on the demand, but the issue is as much supply side. I’ve walked down that path to being an FRC supplier a few times over the years and bottom line is you as the supplier absorb considerable financial risks and if your: manufacturing supplies, shipping, or labor dramatically increase you are going to have supply side limits.

If you really want every team to have something: you generally make it the stuff of KOP. Now the vendor has leverage and that assures demand numbers so they can legitimately set expectations with their suppliers and their finances.

That still is not without risk to the vendors, however. A less experienced or established vendor may never have worked on that scale, so it may prevent them from even starting as they are jumping straight into the fire at scale.

It should be noted that ChiefDelphi searches will turn up examples of Falcon 500s with various failures. Not so much a reflection on the vendor, but then one must consider what happens if a defect or common usage error surfaces further straining that supply line again?

This whole thing reminds me of a motor vehicle supply issue. Over the years I’ve bought several very powerful internal combustion engines for retrofitting hot rods. In many cases I’ve been able to get significant discounts by seeking out engines from failed retrofits or crashed vehicles someone else upgraded. They had more power, sure, but it was just too much to finish the job (cost, quality, time) or too much for them to adequately control.

FWIW, if you really want to keep people from ordering too many of something: impose a limit on the orders and restrict the parts to FRC buyers. Just do not allow that limit to change during the time window of a whole season of FRC, unless the change is inclusion in a KOP. Unfortunately this does still favor older teams as they can easily have left over stock from the previous seasons, so then you need to limit the number of the item you can actually use per robot again.

Ever think that could really screw companies over, like SDS. Their swerve modules were designed for neos or Falcons and cims won’t fit. So essentially you would be chopping the legs off of a company that designed their product for rules that have been in place for years.

6 Likes

So set the limit at 8, it allows teams to choose between the drivetrain and other subsystems

3 Likes

Sure, but now you are pushing for teams to do “creative” solutions like running a motor and versa planetary for steering. Kinda hurts the design intent, and makes swerve more expensive.

2 Likes

Pulls out walker (maybe just a cane as I’m maybe not that old) but I do miss the creative decisions teams made back during the motor limit era. Teams had to make design choices, tradeoffs, and unique solutions to achieve complex goals.

I’ll say, gameplay is more exciting nowadays but we’ve moved away from the Apollo 13 “figure out how to put the pieces together” way of solving a problem vs the “just make more pieces” way.

8 Likes

Given the significant investment many teams have made in brushless motors, it would be a real rough move to suddenly mandate teams to only use some of those motors at this point in the year. 5010 stocked up on NEOs and SparkMAXs and would have spent that money elsewhere if we knew motor types were being limited. If this is something FIRST was interested in doing, it should have already been announced for the 2023 season.

11 Likes

5090 likewise bought our supplies as soon as this years money became available to us. We also donated almost all of our cims and older brushed motors. That would then make us have to spend more money that we don’t really have on old and outdated supplies.

4 Likes

Absolutely not.

I love having only one motor/controller style to worry about. I do not want to bring a huge spread of spares for our team. I don’t want to deal with different styles of gearboxes, non-encoder-equipped motors, or even stock different pinion gears.

Your proposal makes life more miserable across the board. I celebrated every time FRC got rid of motor limitations.

For what it’s worth the proposed type of limitation is not present in industry. In the real world we strive for maximum commonality to reduce spares inventory, purchasing complications, servicing effort, and so on.

23 Likes

My biggest concern is with how fast and therefore dangerous these robots are becoming. So in that sense a motor restriction might be good. I feel like a more elegant approach might be to drop the main breaker rating down to 90 amps or so. Everyone is going to hate that, but tbh 90 amps with the motors we have now seems like less of a design limitation than 120 amps was with the motors available 15 years ago. Not super knowledgeable in this area though, so feel free to ignore me.

3 Likes

While I’m not in favor of motor limits, couldn’t you say the same of Limelight with the introduction of AprilTags?

1 Like

I think you’d want to do something different than cause the robot to stop working mid-match. It isn’t a behavior that most teams would know how to navigate well.

I do think FIRST could work with vendors to come up with some guidance about what products should be sold in restricted quantities based on available stock at time of sale. These guiding documents would be voluntary for the vendors to implement and for the teams to follow.

1 Like

Limelight is still usable, they aren’t doing away with the vision tape right away. They are phasing it out over a couple years and not just changing things months before the season

2 Likes

They’ve been cutting the legs off of RFID vendors for years. It really is brutal and barbaric.

2 Likes