most "epic" motor ever

[DinerKid]

Originally Posted by Lowfategg

I know everyone hates them but I really like denso window motors when used correctly. Non-backdriving and low rpm thanks to the integrated worm gear drive.

Everything else, FP and CIM.

Totally agree. they are definitely one of my favorites. I really like that the Denso gives you an output speed that you can easily work with, there are no massive reductions to deal with in most cases.

My team has a bit of Tim Taylor in them so "just put a CIM on it" can be heard just about every day.

~DK

[sgreco]

My favorite motor was the fifth CIM we got in 2010. It added a really cool twist to the game.

[thefro526]

I'm really liking the RS775-18 thus far. Seems plenty powerful, takes to stalling pretty well (better than an FP) and if it weren't for the transmissions being nearly impossible to get, I'd say they are the best motor in the KOP this year.

One year it'd be nice if FIRST gave us a list of Motors we could use with the only restriction on quantity being a total maximum power output. (Sum of all motor power can't exceed 2000W or something.) That'd be interesting.

[apalrd]

Originally Posted by thefro526

One year it'd be nice if FIRST gave us a list of Motors we could use with the only restriction on quantity being a total maximum power output. (Sum of all motor power can't exceed 2000W or something.) That'd be interesting.

Or they could say "Each motor must have exactly 1 breaker, have fun".

*You can't have gigantic motors because the max. current per motor is limited by the 40a breakers
*You can't have too many large motors because you only have 8 40a breakers
*You can't have a ridiculous number of motors with 30a or 20a breakers, because you only have so many 30a slots as well, and a few things also use those breakers (like the cRio modules).

Favorite motors:
CIM motors are awesome for high-power things like drivetrains.
FP or 550 motors are awesome for high power but more predictably-loaded things (such as arms) or high power, light weight things (like roller claws or other high-up mechanisms)

An AMP or CIM-U-LATOR makes the FP or 550 think it's a CIM.

I would be very happy to just have those two motors. Most things would use a CIM interface, and the limited number of CIMs could be distributed, and the rest could get FP or 550's through CIM-U-LATORs. Anything without a CIM interface would accept a FP or 550 directly.

[ratdude747]

Originally Posted by apalrd

Or they could say "Each motor must have exactly 1 breaker, have fun".

*You can't have gigantic motors because the max. current per motor is limited by the 40a breakers
*You can't have too many large motors because you only have 8 40a breakers
*You can't have a ridiculous number of motors with 30a or 20a breakers, because you only have so many 30a slots as well, and a few things also use those breakers (like the cRio modules).

Favorite motors:
CIM motors are awesome for high-power things like drivetrains.
FP or 550 motors are awesome for high power but more predictably-loaded things (such as arms) or high power, light weight things (like roller claws or other high-up mechanisms)

An AMP or CIM-U-LATOR makes the FP or 550 think it's a CIM.

I would be very happy to just have those two motors. Most things would use a CIM interface, and the limited number of CIMs could be distributed, and the rest could get FP or 550's through CIM-U-LATORs. Anything without a CIM interface would accept a FP or 550 directly.

to your team, anything that can be mounted to a dewalt tranny is fair game

[nahstobor]

Originally Posted by Chris is me

I want a kit that lets you use as many CIMs and Globes as you want, and no other motors. Wouldn't that be nice?

I second that

I liked that gearbox with 6 motors on it that I saw from an '07 game, I think it was called the V6, 4 CIMs, 2 smaller ones. Anyone remember this?

[Andrew Schreiber]

Originally Posted by ThaineP

I liked that gearbox with 6 motors on it that I saw from an '07 game, I think it was called the V6, 4 CIMs, 2 smaller ones. Anyone remember this?

118's V6 was pretty cool.

[Jared Russell]

CIMs are the best permanent magnet DC motors I have ever used - in FIRST, at work, in school, etc. We had been unable to destroy one in 12 years (until this year thanks to an overzealous rookie and some incorrectly sized mounting hardware)!

I like the suggestion for unlimited CIMs and Globes (or a suitably robust similar "small" motor - the RS550s might be up to it).

[JesseK]

Eh, I'd like some sort of constraint on CIMs, just so we don't have 8-motor drive trains that ram into everything in sight or are nearly impossible to get out of the way of. The CIM takes the cake for 'epic' for their robustness.

I like the motors that spin slowly enough out of the box that I don't NEED to gear it down 1000:1 using a $200+ COTS gearbox or multiple sprocket reductions -- the denso's and the globes were PERFECT for that. Need a wrist joint? Just add 1 sprocket reduction after the motor output. To me, it's more of a challenge to figure out how to do things with less available power than it is to use less power via software.

[ChuckDickerson]

[quote=JesseK;1033040]Eh, I'd like some sort of constraint on CIMs.../QUOTE]

How about weight? Each 2.5" CIM weighs aout 2.5 lbs IIRC. 4 = 10lbs, 8 = 20 lbs. Unless someone knows some magic I don't there really isn't any way to lighten them. At some point most teams are going to have to use lighter motors so as not to eat up so much of their 120 lb weight budget. I think allowing 6 CIMs at most would be a reasonable thing to do unless they up the 120 lb weight limit, increase the number of 40A slots on the PD board, and up the 120A main breaker - none of which I see happening anytime soon. There are plenty of contraints already limiting the "unlimited use of CIMS".

[Andrew Schreiber]

[quote=DeepWater;1033098]

Originally Posted by JesseK

Eh, I'd like some sort of constraint on CIMs.../QUOTE]

How about weight? Each 2.5" CIM weighs aout 2.5 lbs IIRC. 4 = 10lbs, 8 = 20 lbs. Unless someone knows some magic I don't there really isn't any way to lighten them. At some point most teams are going to have to use lighter motors so as not to eat up so much of their 120 lb weight budget. I think allowing 6 CIMs at most would be a reasonable thing to do unless they up the 120 lb weight limit, increase the number of 40A slots on the PD board, and up the 120A main breaker - none of which I see happening anytime soon. There are plenty of contraints already limiting the "unlimited use of CIMS".

Don't forget power draw, pulling down 40+ amps for any extended period of time with 8+ CIMS will quickly suck your battery dry.

[JesseK]

[quote=DeepWater;1033098]

Originally Posted by JesseK

Eh, I'd like some sort of constraint on CIMs.../QUOTE]

How about weight? Each 2.5" CIM weighs aout 2.5 lbs IIRC. 4 = 10lbs, 8 = 20 lbs. Unless someone knows some magic I don't there really isn't any way to lighten them. At some point most teams are going to have to use lighter motors so as not to eat up so much of their 120 lb weight budget. I think allowing 6 CIMs at most would be a reasonable thing to do unless they up the 120 lb weight limit, increase the number of 40A slots on the PD board, and up the 120A main breaker - none of which I see happening anytime soon. There are plenty of contraints already limiting the "unlimited use of CIMS".

I'm not so sure I want any team to slap 8 CIMs on their drive train and only to call it a "defensive" robot. Heh. Sorry, our robots have to survive for the post-season while also playing the game without breaking every other match.

It's like the whole debate upon regulations of car safety. More powerful engines and higher speeds equate to more structural strength necessary to prevent deaths on the highways. This means more weight added to cars as well. Rather than limiting power output, the typical regulations are on structure integrity during a crash. If the industry would tone down the power a bit, we wouldn't quite need all of that regulation.

Conversely, since FRC has a pesky weight limit, we do not necessarily have the spare weight for adding more structural integrity to EVERYTHING we design. So I'd much rather the GDC limit the power capabilities to the drive train as a slight preventative measure to prevent 'overkill' scenarios. As it stands right now, teams who want a 6-motor drive train have to do more engineering than just purchasing COTS gearboxes and slapping them on the KOP drive train. That in and of itself is limiting enough for quantity seen on the field, I think.

[artdutra04]

2.5" CIM motors, followed closely by the Banebot RS775-18. While much praise has already been espoused about the versatility and durability of the CIM motors, we've found that the Banebot RS775-18 motors are close runners up. Unlike the other BB motors, the RS775's are champs and won't give up the ghost just because you told them to run at stall for a few seconds. During testing, we learned they'll trip out the Jaguars or circuit breakers long before they'll suffer any harm.

Originally Posted by JesseK

I'm not so sure I want any team to slap 8 CIMs on their drive train and only to call it a "defensive" robot. Heh. Sorry, our robots have to survive for the post-season while also playing the game without breaking every other match.

It's like the whole debate upon regulations of car safety. More powerful engines and higher speeds equate to more structural strength necessary to prevent deaths on the highways. This means more weight added to cars as well. Rather than limiting power output, the typical regulations are on structure integrity during a crash. If the industry would tone down the power a bit, we wouldn't quite need all of that regulation.

Conversely, since FRC has a pesky weight limit, we do not necessarily have the spare weight for adding more structural integrity to EVERYTHING we design. So I'd much rather the GDC limit the power capabilities to the drive train as a slight preventative measure to prevent 'overkill' scenarios. As it stands right now, teams who want a 6-motor drive train have to do more engineering than just purchasing COTS gearboxes and slapping them on the KOP drive train. That in and of itself is limiting enough for quantity seen on the field, I think.

Putting 8 CIMs in a FRC drivetrain won't really accomplish anything other than to deplete one's battery faster. This is because of the major difference between your example of cars and FRC robots: Most FRC robots are traction limited, while cars are usually torque limited. Adding more powerful engines to cars yields better results because torque-limited cars have a large capacity void between what the stock engine puts out and the maximum power than can be utilized by the wheels to make the car go.

On the other hand, adding more power to an FRC drivetrain may actually lower a team's effective pushing power, as dynamic friction is almost always lower than static friction. (Think back to Lunacy). Thus, by having more motors in a drivetrain, they will increase the odds that the motors will be able to overcome the maximum static friction with the ground and start spinning their wheels, thus lowering their ability to push other robots.

Now even if they can overcome the traction limitations, they still have to deal with the relatively small field size. How likely is it that robots will have the room to accelerate to speeds beyond the top speeds of 15-16 ft/sec already seen on many FRC robots? Why do you think teams don't currently use three or four speed gearboxes that can theoretically take their robot to 20, 25, or 30 ft/sec? It's because the field is small enough such that gearing for that speed would never be useful.

[Chris is me]

Originally Posted by artdutra04

Now even if they can overcome the traction limitations, they still have to deal with the relatively small field size. How likely is it that robots will have the room to accelerate to speeds beyond the top speeds of 15-16 ft/sec already seen on many FRC robots? Why do you think teams don't currently use three or four speed gearboxes that can theoretically take their robot to 20, 25, or 30 ft/sec? It's because the field is small enough such that gearing for that speed would never be useful.

While that's one very valid reason, a 4 CIM drivetrain takes a noticeable acceleration hit at around the 18 FPS mark. Current two speeds don't need to auto-shift for acceleration purposes; a faster drive would basically require it.