General Motor Rules
 

So I've been in the stepper thread and it brought back a sentiment that MAYBE we could open up the general motor rules such that you can use any 12V motor you can find so long as it satisfies a wattage limit (and a few other rules).

For example:

#1 No more than:
4x 340W-300W (CIM's)

6x <300W-200W (rs-775-18's & Mini CIM's)

4x <200W-50W (AM 9015's, RS-775-12, & BAG's)

4x <50W (AM PG motor & window motors)

#2 Stall current max: 140 amps.

#3 Must be COTS

#4 Must provide a data sheet (to prove the above)

#5 Must have P/N visible (to prove that #4 is not fake if necessary)

#6 Must be < $400 (2015 single part allowance)

#7 If it's on the allowed list (anything allowed in the 2012-2015 rules?) you can just use it.

Anything I missed?

Obviously inspection can take longer for any team using a lot of different motors but you could subvert this by placing an absolute maximum on non-standard motors. There is also the possibility that someone just fabricates a datasheet but at the end of the day we do trust everyone to bag and tag on their own.

Also please don't assume that the above rules are what I think will absolutely work, it is just an example.

Re: General Motor Rules
 

It'd be simpler to limit motors by form factor, with the two obvious choices to expand being the 500 and 700 sized motors. As in, any 500 or 700 sized brushed motor you can obtain as a COTS item is legal.

Both of which are inherently power limited by their size, and provide a wide range of existing COTS products to interface with.

Re: General Motor Rules
 

Would this only include brushed motors? Brushless motors and steppers would require different controllers, which is probably what's driving a lot of the standardization - ensuring that disabling the robot actually disables the actuators. Opening up to motors not from a specified list also increases opportunity lo lighten motors in what may be an unsafe manner. And what about hand-wound/homemade motors?

Re: General Motor Rules
 

I'd rather do any brushed motor under 350W @ 12V. Unlimited motors etc.. Teams will be limited by motor weight and the battery anyways.

Re: General Motor Rules
 

I hate it when motors halt and catch fire. A bad day usually results.

A motor with too much stall current and not enough heat capacity should not be on an FRC robot. Combining Adam's and R.C.'s criteria might work.

Re: General Motor Rules
 

I think the number of outputs on the PDP would be the limiting factor.

Re: General Motor Rules
 

I mean brushed motors. That and the wattage/current limits from the op are meant to reduce the effect on the rules and inspection by not requiring additional rules for control electronics. The same controllers would still be able to be used.

Re: General Motor Rules
 

I'm curious, is there some written standard for 500/700 series motors? All I've found are actual Mabuchi part numbers as well as other motors claiming to be 500/700 series motors for RC toys. (Or did Mabuchi just set the standard?)

Re: General Motor Rules
 

Is 6 cims, unlimited quantities of half a dozen other motors really not enough variety? We have cheap motors, durable motors, equivalent motors from multiple suppliers, and different size / power motors available; plenty of options. I really think at this point opening up the motor rules further is solving a problem that doesn't exist.

If they are opened up, being able to choose any 500 / 700 series motor seems like the logical next step, but other than that, I'd rather not have teams get competitive advantages from being able to source some super obscure motor that no one else has in stock / knows about.

Re: General Motor Rules
 

DITTO.

[geezer]You young whippersnappers don't know how good y'all have itI Back in my day, we only got 2 drill motors (there's the drivetrain!), a couple o' window motors, a van door motor, pair of Fischer-Price motors (something like a 700-series motor would be about right powerwise), maybe a CIM or two, and who knows you might get a seat motor or two if you was lucky. We only had them motors to power the whole robot! And we liked it--them being delivered in the kit saved us from walking uphill in the snow both ways to get 'em from the post office! Then some wiseacre dropped the drill motors for two more CIMS, canyoubelieveit. And we liked it more! And you're complaining that 6 CIMS and all these other really really nice motors ain't enough???? Why I oughtta get out o' this here rocker and come show you how it's done! Open up the motor rules? They already been opened up![/geezer]

Seriously, folks. If the motor selection currently available doesn't fit your needs, you may want to reconsider how you're doing things. Try pneumatics.


Now, speaking as an inspector: If teams can't even get the numbers right (you'd think that black with a white background, with a given size, spelled out quite clearly in the manual, would be really easy to do), and a missing BOM is a common reason for not being able to pass on the first day of inspection, do you really think they'll remember to bring their datasheets? (For that matter, it seems like every year somebody pulls out a Globe motor, asking what it is--and has to be told it's illegal. At least a lot of them do it on CD before bag day so it can be swapped out.) I really can't say that this is a great idea...


I think someone is missing part of the point of the motor rules. The point of the motor rules is to give every robot the same available maximum power (well... OK, it used to be, until certain motors were classed as unlimited). It also ensures that everybody is using the same motor types--sure makes troubleshooting and spares a lot easier when you can ask a neighboring team and get a motor/help, rather than having to phone the home shop for your spare motors that you forgot.


Rather than loosening the motor rules...

I might suggest limiting the motors to 4 CIMs, 2 Mini-CIMs, 6 775s, 550s, and/or BAG motors (any combination), 3 PG-71s, and unlimited "automotive" motors (window, seat, door). Servos and electric solenoid actuators remain unlimited. Plenty of power in that batch...

Re: General Motor Rules
 

I've never sought one out, but i'm sure it exists.

Re: General Motor Rules
 

The problem isn't lack of options or power it's that the rule is based on P/N not power limitations. I wish I could use dill motors or FP's or any of the 500 & 700 series motors I could find but I can't because they aren't a specified part number.

As others hint the actual limiting factors include the PDP ports, snap action breakers, main breaker, battery, robot weight, motor controller specs, the fact that it must be a brushed DC permanent magnet motor, and physical size of the motor. The amount of power available is already limited. I found an old drill with an "FRS-550" in it and even found a data sheet to prove its similarity to the BB RS-550 but I still couldn't use it. Why? Because it's not that one part number. It doesn't really make sense.

The point is to limit DC brushed motors by voltage, power, and or current not P/N. Just look at how the CIM has to have 9 different P/N's in the 2015 rule book.

Re: General Motor Rules
 

Amen, teams have way to many powerful motors now. We need to get back to the days of having to make decisions about where to use the most powerful motors. I miss this design challenge.

Re: General Motor Rules
 

I don't mind the 2015 motor rules, but I would like to see some sort of limit in drive motors in contact games, as the drivetrain arms race is not fun.

Re: General Motor Rules
 

+1
All that a drive motor arms race does is reward teams with more resources. Increased motors can be helpful for doing things like climbing the pyramid in 2013 in a reasonable amount of time, but in 2015 we had to make a total of zero trade-offs when it came to alotting motors. 20's elevator had 4 motors on it, for example.

Re: General Motor Rules
 

Exactly why I agree with EricH about having stricter motor limits. Having to make significant tradeoffs in how much power to allocate to what mechanism is a fun part of design and encourages creative solutions vs. lets just throw more motors on it until it does what we want.

Re: General Motor Rules
 

I think requiring 12V motors isn't a good idea. The RS-775 everyone uses is an 18V motor, and it runs great, partially because its never running more then 66% of what its rated for. I think the watt and amp limits need to be counted at 12V, but if you want to use a motor rated for higher voltage you should be able to do so. The battery already limits to 12V.

Re: General Motor Rules
 

I did some digging and wasn't able to find a comprehensive standard that covered any given series of Mabuchi motor, but it looks like it'd be simple enough to allow any motor with a Mabuchi part number of of "RS-3XX", ,RS-5XX" or "RS7XX" to be used in FRC, since we've already seen these motors in the KOP (virtual KOP?) at least once.

Personally, and this is only my opinion, the motor rules as currently written, and previously written (at least as long as I've been in FRC) - dont work. I've seen at least two or three robots a season - usually at events where you've got a lot of "one and done" teams, that use illegal motors, usually something from a previous KOP.

I honestly can only think of one time where any inspector ever cared about motors to the point where they checked part numbers, and that was back in 09 - there were three or four RS500 motors at could be used... (Only one of them made sense... We did not use that one) so the inspectors knew to verifying part numbers.

We're almost at a cross road, either limit the motor rules, specifically to CIMs, Mini-CIMs, Bags, 500 cans (AM-9015?) and 700's (AM PG series?). At that point, between the visual uniqueness of the CIM family compared to most other motors, it's hard to mistake one motor for another, and AM has a colorful enough label that it jumps out. (Although RS775-18's are awesome, someone make a colorful label.)

The alternative would be to limit max power win an open(ish) motor list. I think this actually may solve the problem, at least for the most part - but you still run into instances where the same motor may have different specs depending on the vendor - not to mention that you'll have a handful of teams ripping apart drills and other tools to pull motors out, with no real way of verifying the specs.

IMO, in a perfect world, motor allotment is any combination of CIM's, Mini-CIM's, BAGs and RS-series motors under a total of ~3.5-4kw of power. After that point, if you're really using all of that, your batteries will rarely last a match, which creates more problems than it solves, obviously. It also forces teams to make smart decisions about where to use power and where not, rather than the current "all CIM everything". (Although a 3.5kw cap does not prevent one from doing all CIM everything, it just limits what they can do with that mentality.)

Re: General Motor Rules
 

I think we should just use all Mini CIMs and BAG motors.




There will be those that get the joke and those that do not ...

Re: General Motor Rules
 

You mean IFI hasn't developed a 700-series motor yet? Or a BIG CIM? Seriously? :p


Yep, I get the joke.

Re: General Motor Rules
 

Good idea. And smoking motors should be an automatic yellow card.

Re: General Motor Rules
 

I couldn't agree more. My personal preference would be 5 CIM motors (can be freely downgraded to minis), 3 minis (plus downgraded full ones), 5 combined RS/bag/PG motors and unlimited auto motors.

It would also be interesting to see a year with a very strict motor allowance. 3 cims, 4 minis, 4 combined RS/bag/PG motors and unlimited auto motors for example.

What I really think we need is a CHEAP motor controller for the smaller motors. You don't need to withstand 100+ amps of surge current for a window motor. It would also give some much needed utility to these motors.

I inspected a team which used 1 speed controller for 2 cims. It was a bad mistake but it just goes to show that we don't need more complex rules. On that note: open up the servo restrictions.

Re: General Motor Rules
 

THAT one, I'll go for. 4W is pretty weak.

I'd say to allow all micro-servos, and any hobby servos up to some reasonable wattage (10W, maybe? 20? Just throwing some numbers out here...), but nothing that isn't a hobby servo (AKA, nothing industrial).

Re: General Motor Rules
 

The point was not to increase the arbitrary power limit but to limit the power by setting a direct limit on power. Right now the limit is indirectly set by specifying how many of each specific motor a robot can have. I am proposing that either it be set by a total watt limit, a categorical watt limit (see op), or similar method. The limits in the first post can simply be reduced to satisfy a reduced power allowance.

In short the point was to increase the number of different motors we could use not the total wattage of what can legally be attached to the robot.

Edit: I too would like to see an increase in both the servo and solenoid wattage limits.

Re: General Motor Rules
 

Why? Really simply, why? What exactly is the current motor restriction not allowing you to do that you need to do?


Is it just that you want to use a different motor? OK, submit the idea to FIRST to see if they can get the company interested in supplying 3K motor "sets" (a set being anywhere from 1 to infinity motors). A different type of motor altogether? In that case, I ask why you really need that functionality, and look for workarounds. Or is there something I'm not seeing? (I honestly don't see any application for stepper or brushless motors that can't be handled with an additional sensor on the robot and careful motor selection.)


In the real world, the customer doesn't relax requirements just because "it should be this way". The customer only relaxes the requirements if it can be conclusively shown to their satisfaction that the requirements must be relaxed in order to meet other requirements--and usually, that can't be shown! Again, FIRST imitates life...



Now, I bet someone is going to come back with "well why do you favor the servo limits increasing?" And my answer is that it is nearly impossible for teams that don't want to use pneumatics to have multiple speed drivetrains with the servos we have. I've seen teams gang servos to get the required power for some relatively minor jobs. I've very, very rarely seen a servo used on a robot--a "gate latch" a few years ago being one of the cases. Plain and simple, there just isn't enough power available in that group.

Re: General Motor Rules
 

Full disclaimer: I am not a robot inspector, nor have I ever been, but I have been at all of my teams robot inspections from 2011-2014, and I feel that that qualifies me to say what I'm about to say, which has already been echoed in this thread.

Why are we going to make the inspectors' jobs more difficult? Any team that cannot accomplish what they want to build with the motors currently available has bigger issues that the available motor selections. Any team that is going to gain a slight performance boost from some obscure motor somewhere probably already soars above the competition with regard to whatever they are trying to improve.

So, back to the big question, why make inspections harder? Every interaction I've had with an inspector has led me to the conclusion that they are there to make sure that our robot gets on the field and doesn't explode/hurt people/break other robots with fire/anger insurance agents, and THEY ARE THERE FIRST AND FOREMOST TO HELP. Opening up the motor rules would require teams to bring in documentation and prove that their motors are indeed what they claim they are (with data sheets, etc, that teams will inevitably forget to provide). On top of that is the problem that motor spec sheets don't always have accurate data in the first place (BaneBot 550), so now inspectors have to judge whether those high school kids with the wire birdsnest plugging in random motors they found on eBay that draw 100+ amps of current are safe and within the confines of the rules. Rules, I might add, that solved a problem that didn't exist in the first place.

So, in short, opening up motor the allotment solves a problem that doesn't exist and creates unnecessary headaches for volunteers that already have a lot of stuff on their plate, all while lengthening the inspection process, and in the process slowing down the teams that followed rules to the T and now want to get on the field on practice day.

My vote would be, go back to the motor rules we had in 2011. There were enough motors there to do whatever we wanted, not enough for a drivetrain arms race, and just enough limitation that teams were forced to make tradeoffs on design. For posterity, those rules were: 4 CIM's (we could say now and/or MiniCIM's), 4 Banebots, FisherPrice Motors from the KOP, window motors from the KOP, and maybe now a couple AndyMark or BAG motors

Re: General Motor Rules
 

Similar motor rules to 2011 makes a lot of sense.

4 CIMs, 2 MiniCIMs, 4-6 BAGs/Banebots/AM/Fisher Price, Unlimited Window motors/Servos

If you need more motors than that, I don't know what to say. (20's 2015 robot had 12 motors on it: 4 CIMs, 6 BAGs, and 2 window motors. The original version of it had 4 CIMs and 8 BAGs, but without the window motors)

Re: General Motor Rules
 

I'd like to see more than 4-6 BAG/BaneBots/AM motors, but more strict CIM and miniCIM restrictions would be appreciated. Unlimited miniCIMs is just absurd.

Re: General Motor Rules
 

Why?

Re: General Motor Rules
 

The proposal to open up 500 and 700 sized motors makes it easier for inspectors.

Does it look like a 500 or 700? Well it's most likely legal.

Re: General Motor Rules
 

I'm not trying to get one specific motor legalized and this thread isn't about stepper motors or brushless motors. The point is to make use of any comparable motors regardless of P/N. It has nothing to do with trying to obtain a marginal increase in power form an obscure motor. I am asking for the freedom to source and use similar motors at will. This has nothing to do with changing the allowed number of motors on a robot/total allowed power.

We already see teams short, stall, smoke, our current selection. We have snap action and main breakers, the motor will only have a 12V power source, and it's an 18ah lead acid battery. Thus regardless of the motor specs the electrical system will not allow more power output or current draw and won't pose more of a threat to the operators. If teams already burn out BB 550's what is the problem burning out a 550(ish) motor?

As for inspection, relax the restriction and base it off of simple criteria (like Adams idea). Don't change anything in the control or electrical system. You could even limit the motors to the 20 amp circuits like the custom circuit rules if that is a concern.

Re: General Motor Rules
 

And you'll get a new arms race of teams trying to source the most optimal (powerful, power density, power/weight ratio, whatever criteria you want) motor. Could be hard to find, or prohibitively expensive for lower resource teams to obtain; many of which won't even know the motor exists. This would just widen the already large disparity between the top and the bottom of FRC teams.

Re: General Motor Rules
 

It's a relatively bounded arms race though, as 500 and 700 sized motors only get so powerful at 12V.

Re: General Motor Rules
 

They do, but remember 2012? The superpowered FPs were so hard to find, and I remember a lot of teams complaining about the race to get those.

If anything, I would say allow motors by brand, and specifically allow a few different brands. That way the teams that needed could walk into their local hobby store and get some RC car motors, or a place like AM could sell specific ones that meet teams needs, such as the current 775 and 550.

Re: General Motor Rules
 

Yes they were, but comparably powerful 500 sized motors (with different part numbers) were readily available.

Re: General Motor Rules
 

Yes, but it gives a huge benefit to teams who can identify and source the most powerful motors in those series. My fear is that you'll have low resource teams limited to what's in the KoP and available from AM/VEX, while teams with mentors with industry experience will have a tangible power advantage. These teams already have many advantages as is (all well deserved), I don't see the need to make a rule change that will only widen a gap that much of our community is already concerned about. This is similar to the arms race that occurred with minibot battery chargers in 2011. Most teams just used the Tetrix chargers, while some teams used advanced chargers which allowed for a measurable difference in output speeds.

I love the simplicity of what you've proposed, but for me to get behind the issue, FIRST would need to identify a vendor which has a steady supply of motors in at least 75th percentile (perhaps much higher depending on the marginal power increase available around the 75th percentile) of power available in the form factor.

Re: General Motor Rules
 

Oh, I agree and don't see a big reason to change rules as currently the amount of COTS motors easily available is FAR better than even a few years ago. I'm moreso saying that if we do, this a reasonable direction to go (relatively constrained) as compared to checking total power, etc...

Tangentially related, we use the regular tetrix chargers like noobs in 2011...

Re: General Motor Rules
 

Wouldn't it then actually serve both goals to say: N Cims and an unlimited number of Bag, Mini CIM, and AM 9015 motors[1].

No team has an advantage in finding a better motor. Inspectors now only have 4 motors to identify. Simpler on teams, simpler on inspectors. No serious advantage to teams who can find a slightly better motor. All motors have a wide variety of COTS interface solutions (interfacing with the old FP gearboxes sucked) The only downside is I'd like to see a lower power motor added but we could open up servo limits (say 20W) and that would fill that need.


Course, I don't understand why we need MORE variety in motors.

[1] I picked a motor that's widely available from a supplier familiar with FIRST ordering and timelines.

Re: General Motor Rules
 

Won't SOMEBODY think of the poor little throttle motors?!?!

Re: General Motor Rules
 

Oh well, it was [not] worth a shot. While were at it how about going to 24V?

Re: General Motor Rules
 

By going to 24V you obsolete every current FRC motor.

Re: General Motor Rules
 

And a lot of the electrical system.

Re: General Motor Rules
 

No worries you just run all the appendages off of one large motor. The tank drive would use dog gears to reverse and disconnect power on each side and belts and shafts transmit torque to other parts of the robot. It'd work like a early factory or mill with one big steam engine in the basement and line shafts for power transmission.