View Full Version : FRC Blog - 2016 Motor Controllers
http://www.usfirst.org/roboticsprograms/frc/blog-2016-motor-controllers
Today’s blog post was written by Kate Pilotte, FIRST Robotics Competition’s Kit of Parts Manager.
You may have noticed that every now and then we release information about a season before its Kickoff; sometimes it’s because we think it’s just that helpful to know ahead of time, sometimes it’s because we’re being playful, and sometimes it’s an accident.
This instance is the first one.
We want you to know that the list of legal motor controllers for the 2016 season is expanding.
In addition to the controllers permitted in the 2015 season…
Jaguar Motor Controller (Part #s: MDL-BDC, MDL-BDC24, & 217-3367)
Talon Motor Controller (Part #s: CTRE_Talon, CTRE_Talon_SR, & am-2195)
Talon SRX Motor Controller (Part #: 217-8080 & am-2854)
Victor 884 Motor Controller (Part #: VICTOR-884-12/12)
Victor 888 Motor Controller (Part #: 217-2769)
Victor SP Motor Controller (Part #: 217-9090)
…we’ve also approved the following devices:
SD540 Motor Controller (http://www.mindsensors.com/frc/135-motor-controller-for-frc) (Part #: SD540x1)
(mindsensors.com has been a long time mentor of FIRST Team 540 and designed this controller jointly with Team 540 students. This controller is manufactured locally with the help of FIRST students. SD540 features include brake/coast, direction selection, 60-amp continuous current and 100 amps peak. It will be available as a single unit, dual or quad banks. They expect availability in early November.)
Spark Motor Controller (http://www.revrobotics.com/SPARK) (Part #: REV-11-1200)
(REV Robotics is a Texas-based company founded by two long-time FIRST team mentors. The Spark features 60-amp continuous current with passive cooling, bi-directional limit switch inputs on-board for smart mechanism control, RGB LED status indicator, and digital brake/coast mode. Sparks will be available for purchase in November from Amazon and REVRobotics.com.)
Every team will get a voucher to order three Victor SPs or two Talon SRXes from Vex Robotics. Additionally, Rookie teams will receive 2 Victor SPs in their Kickoff Kit. There will also be limited quantities of Victor 888s, Victor SPs, Talon SRXes, and Sparks in FIRST Choice.
There’s another nugget of information that you should know… what motor controllers won’t be allowed to control. Considering their obsolescence and resulting scarcity on the market, BaneBots’ 550 and 775 motors will no longer be included on the list of legal motors.
For technical questions about any of the legal controllers, we recommend you contact the Supplier directly.
We’re excited to work with all of the motor controller suppliers for this upcoming season!
Eight, count them, EIGHT legal motor controllers!
Ty Tremblay
29-10-2015, 12:24
There’s another nugget of information that you should know… what motor controllers won’t be allowed to control. Considering their obsolescence and resulting scarcity on the market, BaneBots’ 550 and 775 motors will no longer be included on the list of legal motors.
Whoa...
Thad House
29-10-2015, 12:28
Losing the 550's and 775's is going to be a major blow to FRC teams if they do not find another supplier. Right now there is a VERY large gap in the motor chart between 150W and 300W. And with the 300W motor being a CIM, you are basically limited to 150W for any single motor, unless you have room to fit a CIM. I hope they can find a new supplier for a ~220W-250W motor, in 775 size.
I'm assuming the AndyMark versions of the 500/775 will still be available. They're still listed on the AM website.
Monochron
29-10-2015, 12:37
There’s another nugget of information that you should know… what motor controllers won’t be allowed to control. Considering their obsolescence and resulting scarcity on the market, BaneBots’ 550 and 775 motors will no longer be included on the list of legal motors.Whoa...
I was literally about to order around 10 775 motors today. Thank god I procrastinate sometimes....
Thad House
29-10-2015, 12:38
I'm assuming the AndyMark versions of the 500/775 will still be available. They're still listed on the AM website.
Yes they are, however they are nowhere close to the power provided by the banebot motors. The 9015 is 179W vs 253W, and the AM 775 is only 150W vs 273W. So there are similar size motors, but nowhere near similar power. That means if you want more then 250W in a motor you either need to double up motors, or go to a CIM, where there just sometimes isn't space.
Jay O'Donnell
29-10-2015, 12:41
Does anyone else dislike that it feels like they tried to stick the information about the 775 and 550 into a blog post? It's like they didn't want us to notice or something. This is a fairly large deal that teams need to know about and it feels like an add-on to a blog post that not everyone would normally read.
Michael Hill
29-10-2015, 12:43
Does anyone else dislike that it feels like they tried to stick the information about the 775 and 550 into a blog post? It's like they didn't want us to notice or something. This is a fairly large deal that teams need to know about and it feels like an add-on to a blog post that not everyone would normally read.
Where would you suggest they put this kind of information? Blog posts are one of the more effective means of communicating to the teams. I'm sure it will come out later in an e-mail blast to the teams, just the blog post came out ahead.
Does anyone else dislike that it feels like they tried to stick the information about the 775 and 550 into a blog post? It's like they didn't want us to notice or something. This is a fairly large deal that teams need to know about and it feels like an add-on to a blog post that not everyone would normally read.
In my mind they're doing us a favor. They're under no obligation to tell us what motor controllers or motors are legal until the manual is released.
I am surprised about the decision concerning 775s. Banebots discontinuted the motor but still has ~2300 in stock, and I imagine lots of veteran teams have big stockpiles of these motors.
Michael Hill
29-10-2015, 12:45
In my mind they're doing us a favor. They're under no obligation to tell us what motor controllers or motors are legal until the manual is released.
That's exactly how I feel. I'd much rather know now in a blog post than to read it in the rules.
In my mind they're doing us a favor. They're under no obligation to tell us what motor controllers or motors are legal until the manual is released.
+1 I feel like letting us find out Kickoff Day is their regular MO, so this is great.
AdamHeard
29-10-2015, 12:49
Yes they are, however they are nowhere close to the power provided by the banebot motors. The 9015 is 179W vs 253W, and the AM 775 is only 150W vs 273W. So there are similar size motors, but nowhere near similar power. That means if you want more then 250W in a motor you either need to double up motors, or go to a CIM, where there just sometimes isn't space.
That's assuming you trust the banebots power rating. Many people suspect they were over rated performance wise.
Monochron
29-10-2015, 12:51
In my mind they're doing us a favor. They're under no obligation to tell us what motor controllers or motors are legal until the manual is released.
I am surprised about the decision concerning 775s. Banebots discontinuted the motor but still has ~2300 in stock, and I imagine lots of veteran teams have big tockpiles of these motors.
He's talking about hiding in a blog post that is talking about something else. It's like a rider on a bill.
The news of the motors being disallowed was going to make teams upset, so I figure they wanted to temper that by informing us in an otherwise very positive blog post.
Too bad that the focus is on this instead of REV and MindSensors' new products.
AllenGregoryIV
29-10-2015, 12:53
+1 I feel like letting us find out Kickoff Day is their regular MO, so this is great.
If I remember correctly when we lost Fisherprice motors in 2013 we didn't know until kickoff.
The banebots issue has been on the horizon for a while if you read this thread (http://www.chiefdelphi.com/forums/showthread.php?t=137652&highlight=banebot+775).
As far as motors go we have been pretty spoiled the last few years having MiniCIMs, BAGs, AM motors, BB motors, and more. There a lot of people who don't remember the days of designing arms that were powered by van door motors. Don't get me wrong I love more motor power as much as the next guy, namely because I think it makes the robots more entertaining but if we have to go without for a few seasons teams will adapt.
techhelpbb
29-10-2015, 13:10
Happy to see the competition for this non-optional FIRST part!
I'll buy at least one of each of the new products for my R&D bots.
Joe Johnson
29-10-2015, 13:11
That's assuming you trust the banebots power rating. Many people suspect they were over rated performance wise.
I have designed a ton of applications with those 775 motors using the specs published by Banebots (Scorpion (http://www.youtube.com/watch?v=O_q_fEbZSp0), Overclock's robot from last year, had 14 of those bad dads on her), I have never had a case where I said to myself, "those specs are messed up!" When we design our lift to raise 6 totes at 2ft per second, the lift raised 6 totes at 2ft per second.
Of course there is variation from motor to motor but nothing out of the normal manufacturing tolerances (typical for this style of motor is +/-15%).
If you knew what your were doing, those motors were amazing. More power than a Mini-CIM at less that half the weight and volume.
I will serious miss those motors.
Dr. Joe J.
AdamHeard
29-10-2015, 13:17
I have designed a ton of applications with those 775 motors using the specs published by Banebots (Scorpion (http://www.youtube.com/watch?v=O_q_fEbZSp0), Overclock's robot from last year, had 14 of those bad dads on her), I have never had a case where I said to myself, "those specs are messed up!" When we design our lift to raise 6 totes at 2ft per second, the lift raised 6 totes at 2ft per second.
Of course there is variation from motor to motor but nothing out of the normal manufacturing tolerances (typical for this style of motor is +/-15%).
If you knew what your were doing, those motors were amazing. More power than a Mini-CIM at less that half the weight and volume.
I will serious miss those motors.
Dr. Joe J.
The 550 is where I noticed performance differences. We never ran the 775s on anything critical so I'm unsure on them.
I'm confused what the point of designing a motor controller for 60 amp continuous is if the largest breaker we are allowed to use is 40 amps. I understand the higher peak, but the I was under the impression that breakers would snap once you get above 40 amps for more than a few milliseconds. It would make sense if these were already being produced and are just now being approved for FRC, but the blog post makes it sound like they were developed specifically for FRC teams.
Mike Marandola
29-10-2015, 13:33
I guess that explains why there were so many 775s, 550s, and P60s available in FIRST Choice this year.
Thad House
29-10-2015, 13:37
The 550 is where I noticed performance differences. We never ran the 775s on anything critical so I'm unsure on them.
We've used lots of 775s and they were always fairly close to what we had calculated them to be. What made that motor so great was it was an 18v motor so it ran super cool even at stall because it was only 12v. That motor surely will be missed by many teams.
AllenGregoryIV
29-10-2015, 13:40
I'm confused what the point of designing a motor controller for 60 amp continuous is if the largest breaker we are allowed to use is 40 amps. I understand the higher peak, but the I was under the impression that breakers would snap once you get above 40 amps for more than a few milliseconds. It would make sense if these were already being produced and are just now being approved for FRC, but the blog post makes it sound like they were developed specifically for FRC teams.
Your millisecond estimate is the part that is incorrect. Here is the data sheet for the 40 amp snap action breaker (http://www.snapaction.net/pdf/MX5%20Spec%20Sheet.pdf). They can sometimes hold 200% over the rating for a maximum of almost 4 secs.
The current ratings on these types of breakers tell you when they won't trip, not when they will trip.
Jared Russell
29-10-2015, 13:41
Banebots 775s have always matched the advertised specs for us (modulo case shorting issues in 2011).
Banebots 550s have always provided substantially less torque than advertised for us.
Aren Siekmeier
29-10-2015, 13:41
I'm confused what the point of designing a motor controller for 60 amp continuous is if the largest breaker we are allowed to use is 40 amps. I understand the higher peak, but the I was under the impression that breakers would snap once you get above 40 amps for more than a few milliseconds. It would make sense if these were already being produced and are just now being approved for FRC, but the blog post makes it sound like they were developed specifically for FRC teams.
Check out the spec sheet (http://files.andymark.com/MX5SpecSheet.pdf) for the 40A breakers in the kit. They can sustain 200% of their rating (80A) for over a second before tripping, and often do when the robot is accelerating. Edit: Allen got me ::ouch::
Yes they are, however they are nowhere close to the power provided by the banebot motors. The 9015 is 179W vs 253W, and the AM 775 is only 150W vs 273W. So there are similar size motors, but nowhere near similar power. That means if you want more then 250W in a motor you either need to double up motors, or go to a CIM, where there just sometimes isn't space.
Which is the Andymark 775 that's rated at 150W? I only see the 9015 (~179W) and the motors used in PG gearboxes, which are closer to 40W. :confused:
I'm confused what the point of designing a motor controller for 60 amp continuous is if the largest breaker we are allowed to use is 40 amps. I understand the higher peak, but the I was under the impression that breakers would snap once you get above 40 amps for more than a few milliseconds. It would make sense if these were already being produced and are just now being approved for FRC, but the blog post makes it sound like they were developed specifically for FRC teams.
Breakers exist to protect the wiring, not the device. Breakers can and will pass current in excess of the rated current. If you draw 80 amps, the 40 amp breakers used by FRC will not trip before 1 second passes.
For what it's worth, the Victor 888, Victor SP, Talon SR and Talon SRX are all also rated for 60A continuous. If I remember correctly, most of the components in the Talon SR are rated for 100 amps continuous. I think it's good that a device designed for use by high schoolers is rated for more than the expected conditions.
Greg Needel
29-10-2015, 13:44
I'm confused what the point of designing a motor controller for 60 amp continuous is if the largest breaker we are allowed to use is 40 amps. I understand the higher peak, but the I was under the impression that breakers would snap once you get above 40 amps for more than a few milliseconds. It would make sense if these were already being produced and are just now being approved for FRC, but the blog post makes it sound like they were developed specifically for FRC teams.
When someone wants to design a motor controller for FRC, FIRST will provide you a document with their required specifications. One of those requirements is 60 amp continuous operation.
While this may seem like over kill when you do have a 40amp breaker, a factor of safety is a very common thing for equipment like this. It is easy to under estimate the power of 40 amps because we are around it so much on robots but this amount of power density can be extremely dangerous if not done correctly. Back in the "old days" it was not uncommon to see a robot fire or two at a regional event.
We test our controllers to failure at 100amps, to make sure they are as solid and reliable as possible for teams.
Scott Kozutsky
29-10-2015, 13:53
Is anyone else excited about the new speed controllers? They're $45 and $50 respectively. This is an awesome thing for the vast majority of teams as it means you can execute your plans and make mistakes for cheaper. I'm still waiting for $20 speed controllers for the automotive motors. It's also really nice that teams can use the older motor controllers for the same reason.
So many new motor controllers but no new relays? :(
So many new motor controllers but no new relays? :(
What do we need relays for anymore? (Note that Spikes are discontinued (http://www.vexrobotics.com/vexpro/motors-electronics/217-0220.html).) The pneumatic compressor runs through the PCM, and if you absolutely need relay-type control for something, programming a speed controller act like a relay is trivial.
notmattlythgoe
29-10-2015, 14:55
What do we need relays for anymore? (Note that Spikes are discontinued (http://www.vexrobotics.com/vexpro/motors-electronics/217-0220.html).) The pneumatic compressor runs through the PCM, and if you absolutely need relay-type control for something, programming a speed controller act like a relay is trivial.
That, and there are only 4 relay ports on the rio now.
What do we need relays for anymore? (Note that Spikes are discontinued (http://www.vexrobotics.com/vexpro/motors-electronics/217-0220.html).) The pneumatic compressor runs through the PCM, and if you absolutely need relay-type control for something, programming a speed controller act like a relay is trivial.
Spikes are $10 cheaper than the least expensive motor controller, and most veteran teams have bunches of them.
This is in the blog post:
Talon Motor Controller (Part #s: CTRE_Talon, CTRE_Talon_SR, & am-2195)
Talon SRX Motor Controller (Part #: 217-8080)
Having just ordered four Talon SRX's from AndyMark, I would expect them to be legal, but I don't see the AM part number like in the Talon line above it. It's AM-2854. I would expect it's just an oversight on Kate's part.
Also, I agree with Joe. I like the 775s and I will miss them.
What do we need relays for anymore?
Was hoping for a <$20 60A relay for intakes, internal rollers, etc. Flywheels as well, if you can get acceptable performance out of a bang-bang controller.
Was hoping for a <$20 60A relay for intakes, internal rollers, etc. Flywheels as well, if you can get acceptable performance out of a bang-bang controller.
I feel like this is asking for a lot. It would have to be an electrical relay, since mechanical relays can't switch fast enough for bang-bang control. At that point, most people would have a hard time distinguishing an electrical relay from an actual speed controller.
Where would you suggest they put this kind of information? Blog posts are one of the more effective means of communicating to the teams. I'm sure it will come out later in an e-mail blast to the teams, just the blog post came out ahead.
Actually a Blog post is not that good of a way to share this kind of important information as overall not that many people look there on a regular, consistent basis, if at all.
Spikes are $10 cheaper than the least expensive motor controller, and most veteran teams have bunches of them.
I don't see them being legal if there if not an option for all teams to get them or something equivalent during the season.
We stopped using spikes for anything besides window motors because of the annoying tendency to blow the fuse with the bigger motors.
This is in the blog post:
Having just ordered four Talon SRX's from AndyMark, I would expect them to be legal, but I don't see the AM part number like in the Talon line above it. It's AM-2854. I would expect it's just an oversight on Kate's part.
Your concern has been answered. :]
Submitted by Kate on Thu, 10/29/2015 - 15:04.
Added alternate AndyMark part number for the Talon SRX.
Michael Hill
29-10-2015, 16:04
Banebots 775s have always matched the advertised specs for us (modulo case shorting issues in 2011).
Banebots 550s have always provided substantially less torque than advertised for us.
I'll concur with this assessment. We originally used two 550s on our elevator this year only to have them not have enough torque to perform to our expectations. Using the BB specs, it should have been no problem for us.
MrRoboSteve
29-10-2015, 16:53
What do we need relays for anymore? (Note that Spikes are discontinued (http://www.vexrobotics.com/vexpro/motors-electronics/217-0220.html).)
Any chance that Spikes will be disallowed this year, based on their lack of availability? Might drive us to buy more speed controllers.
(Note that Spikes are discontinued (http://www.vexrobotics.com/vexpro/motors-electronics/217-0220.html).)
Given that, I would expect that Spikes will not be legal for switching motors. They may still be permitted for LEDs and other CUSTOM CIRCUITS, however. Most custom circuits can be more efficiently and less expensively switched with a relay module (https://www.google.com/search?q=5V+Relay+module&ie=utf-8&oe=utf-8). You can replace 4 spikes for around $20 unless you need more than 10A per relay.
waialua359
29-10-2015, 17:01
Im pretty sad about not having the use of 775 and 550's anymore.
This is also why I need to STOP stockpiling motors (just like the old FP motors).
These were very cheap and took up such a small volume. Worst news I heard all year........:mad:
BBray_T1296
29-10-2015, 17:09
I am assuming both new motor controllers don't do CAN? Neither website says anything to either effect.
EDIT: I see on the CD thread for the SPARK that it doesn't support CAN.
Am I sad to see the 775 go? Yes it was a great little motor.
On the other hand I think the massive expansion of motors the last few years has not been a good thing. I would love to see a big reduction of available power via motors for the design challenge.
Munchskull
29-10-2015, 17:20
So with the Banebot motors out of FRC (R.I.P.) what would be the new go to motors in terms of power?
Edit: Quick research (http://www.usfirst.org/sites/default/files/uploadedImages/Robotics_Programs/FRC/Game_and_Season__Info/2014/2014_Motor_Information.pdf) yields that the Andymark 9015 Motor (http://www.andymark.com/product-p/am-0912.htm) might be the next strongest that is not a CIM-class motor. Is this correct?
Ryan_Todd
29-10-2015, 17:21
I want to know whether or not the dual- and quad-bank SD540s will come at a discount with respect to buying two or four of the singe units...
Also, what happens if I manage to fry one out of a bank of four?
Inquiring minds want to know!
Very excited about additional motor controllers. A bit concerned about the lack of "vented" motors on the list. 550s and 775 had their issues with stall, but when done right, the air cool was nice for consistent performance.
Anyone have issues with BAG motors overheating in heavy competition? I would assume they get and stay hot similar to CIMS which is a bit concerning when you have back to back matches. Any experience?
BBray_T1296
29-10-2015, 17:44
I want to know whether or not the dual- and quad-bank SD540s will come at a discount with respect to buying two or four of the singe units...
Also, what happens if I manage to fry one out of a bank of four?
Inquiring minds want to know!
From the picture on the website, It looks like just 4 independent circuits inside one large 3d printed case (instead of 4 single cases). I would imagine you could remove a burnt out one, buy a single replacement, and do a drop-in.
sanddrag
29-10-2015, 17:48
Banebots 775s have always matched the advertised specs for us (modulo case shorting issues in 2011).
Banebots 550s have always provided substantially less torque than advertised for us.Ditto for us in 2015.
cadandcookies
29-10-2015, 18:17
Am I sad to see the 775 go? Yes it was a great little motor.
On the other hand I think the massive expansion of motors the last few years has not been a good thing. I would love to see a big reduction of available power via motors for the design challenge.
I think that many teams face enough of a design challenge just fielding a robot without adding more restrictions to motors.
I think that many teams face enough of a design challenge just fielding a robot without adding more restrictions to motors.
I'd argue that the teams who have trouble fielding a robot are definitely not running into the motor power limit.
I think that many teams face enough of a design challenge just fielding a robot without adding more restrictions to motors.
I agree with Knufire. WARNING: You just woke up a geezer!
Back in my day, we didn't have no stinkin' 775 motors! Didn't have more'n TWO, count 'em, TWO, CIMs! Unlimited motors? HAH! We was lucky ta get more'n two of any one motor! And we didn't have all this selection of controllers either--all we had were Victor 884s! And Spikes! And don't get me started on the gearboxes! You think more restrictions means harder challenge, you're darn right, maybe it's ACTUALLY a challenge now! You young whippersnappers these days...
All right, back to seriousness... You get two drill motors, two CIM motors, two Fischer-Price motors, two Globe motors with attached gearbox, two window motors, and one van door motor. Build a robot that can play Recycle Rush. I can do it with two drills, one CIM, and one van door motor (and a couple of pneumatic cylinders). Won't be very fast, but I'm pretty sure that it'd be a second-rounder for consistency. (Hint: I've done it--2003.) By the way, that's the actual motor list from around '03-04 timeframe--we didn't get the second pair of CIMs until '05 and lost the drill motors to get it. And somehow, everybody showed up with a robot that--at least in general--ran, and most of them actually ran pretty well.
This whole "unlimited high-power motor" thing has been kind of... well, I don't know. It is what it is, but I'm thinking that it was about time for it to end. Maybe we'll get some contact back next year with the power dialed down...
Darkseer54
29-10-2015, 20:40
...
Remember, they are trying to get more people into FRC. A big part of this is making the viewing experience intense and/or exciting. While a more difficult challenge may make for interesting and complex designs, the last thing I would want to do to a game like RR is slow down the speed with which teams can make stacks. People want to see robots not only working, but continuing to work faster and faster until they are making record pace. People want to see these robots doing things that humans can't (or at least that's what we are always asked to show at demos and such.) Limiting motors limits robots capacities to accomplish these feats, and while some teams will be able to work around these constraints, a majority of teams will just have another constraint pushing them towards having mediocre rather than competitive robots.
I would love to see a big reduction of available power via motors for the design challenge.
The roboRIO brownout schedule isn't harsh enough for you?
I wouldn't be surprised if we see flywheels on the top teams' robots next year to provide that eleven* when the roboRIO and bumpers are in the same game.
* - reference to the movie Spinal Tap (https://en.wikipedia.org/wiki/Up_to_eleven). Though the Poofs and Simbotics and RoboWranglers are likely to get around seventeen.
Limiting motors limits robots capacities to accomplish these feats, and while some teams will be able to work around these constraints, a majority of teams will just have another constraint pushing them towards having mediocre rather than competitive robots.
Limiting motors does not limit a robot's capacity to perform any feat (at least, in FRC it does not--in the real world, it probably would).
The REAL limitation on the robot's capacity is the TEAM that builds it saying "we don't have X, that means that we can't do Y like we usually do, maybe we shouldn't do Y" instead of saying "we don't have X, we are going to have to find some other way to do Y that doesn't involve X". There are usually quite a few ways to accomplish the exact same goal, and this is particularly true in FRC. (Unless you count driving in '09.)
Go watch some of those older game videos. See just how good these teams were with what they had back then--and remember, they did what they did with a prohibited materials list that was longer than the allowed materials list, a far more restrictive motor/speed controller set, and in many cases virtually no pneumatics (those were limited too!). Even in '06, there was a pretty strict motor limitation--sure, BB supplied some gearmotors, and sure there was an extra type of CIM (the Big CIM), and sure 4 CIMs were legal--but can you argue that that wasn't an exciting game? There were still some pretty limited motors that year...
Can't feel too bad about the 550s as long as the AM 9015 is still available. The loss of the 775 18v is saddening though; they were my go-to motor for shooters and powerful manipulators. Now I have to switch to the 3x as heavy minicim for my stuff, not to mention their much larger size.
I have seen videos of many old games, and I have to say that the newer styles would knock the old ones out of the park. Today's 254 or 1114 or 148 (etc) could beat entire championships alliances of back then from what I can see. It was definitely a slower game back then.
Mike Marandola
29-10-2015, 23:03
Worst news I heard all year:mad:
Hmmmm (http://www.usfirst.org/aboutus/2017-first-championship-announcement)
Tom Line
29-10-2015, 23:36
Very excited about additional motor controllers. A bit concerned about the lack of "vented" motors on the list. 550s and 775 had their issues with stall, but when done right, the air cool was nice for consistent performance.
Anyone have issues with BAG motors overheating in heavy competition? I would assume they get and stay hot similar to CIMS which is a bit concerning when you have back to back matches. Any experience?
Bag motors are awesome in terms of durability. In fact we swapped out our 550 and later 775 with a bag motor on our 2014 catapult, because the bag motor can handle comparatively long periods at stall without giving up the magic smoke. We swapped all our intake mechanisms to bag motors that year too.
cadandcookies
30-10-2015, 01:02
I agree with Knufire. WARNING: You just woke up a geezer!
Back in my day, we didn't have no stinkin' 775 motors! Didn't have more'n TWO, count 'em, TWO, CIMs! Unlimited motors? HAH! We was lucky ta get more'n two of any one motor! And we didn't have all this selection of controllers either--all we had were Victor 884s! And Spikes! And don't get me started on the gearboxes! You think more restrictions means harder challenge, you're darn right, maybe it's ACTUALLY a challenge now! You young whippersnappers these days...
All right, back to seriousness... You get two drill motors, two CIM motors, two Fischer-Price motors, two Globe motors with attached gearbox, two window motors, and one van door motor. Build a robot that can play Recycle Rush. I can do it with two drills, one CIM, and one van door motor (and a couple of pneumatic cylinders). Won't be very fast, but I'm pretty sure that it'd be a second-rounder for consistency. (Hint: I've done it--2003.) By the way, that's the actual motor list from around '03-04 timeframe--we didn't get the second pair of CIMs until '05 and lost the drill motors to get it. And somehow, everybody showed up with a robot that--at least in general--ran, and most of them actually ran pretty well.
This whole "unlimited high-power motor" thing has been kind of... well, I don't know. It is what it is, but I'm thinking that it was about time for it to end. Maybe we'll get some contact back next year with the power dialed down...
I can appreciate what you're saying-- especially with people who have been around a while, I think adding more challenge is an appealing thing. If I was working with a different team, I might even be of the same opinion.
I realize this may be me being a "youn'in" but loose motor restrictions help lower resource teams build better robots. The robot 2667 built this last year wouldn't have been possible for the team to build before the 6-CIM era-- and the team did not have the technical knowledge to apply a different motor to the same tasks we used a CIM for (drive motors and an elevator).
While I'm currently working with my team to start building up a better knowledge of technical subjects, there are plenty of teams that are in that boat every year (probably mostly rookies and not nearly 7-year veterans, but still). I understand the argument that applying more motor constraints would force these teams to learn more, but people learn at far different paces and teams without major technical mentors have serious difficulties building up a knowledge base for the things that people on Chief Delphi and moderately successful teams take for granted.
Coming from the other end... frankly I don't really care to put limits (that generally seem quite arbitrary and can be worked around) on what teams like 254 and 1114 can do with their robots. I like to see robots that move and do things quickly, and the public generally finds those kids of robots more exciting. More motors (and no power limit) helps make that possible for more teams.
The robot 2667 built this last year wouldn't have been possible for the team to build before the 6-CIM era-- and the team did not have the technical knowledge to apply a different motor to the same tasks we used a CIM for (drive motors and an elevator).
There's still the miniCIM and several (http://www.andymark.com/product-p/am-0932.htm) COTS (http://www.andymark.com/AM-Planetary-Gearbox-p/am-0002.htm) gearboxes (http://www.vexrobotics.com/cim-ile.html) that (http://www.vexrobotics.com/versaplanetary.html) can be mounted and interface with components in nearly the same way a CIM can. One even comes with a very easy-to-read guide (http://content.vexrobotics.com/vexpro/pdf/VEXpro_VersaPlanetaryLoadRatings_20140211.pdf) on how to use it without breaking it.
I understand what you're saying about lowering the technical barrier of entry for teams, but I don't think that motor allotment is something that greatly affects this barrier, especially with the availibity of COTS products that will let you use almost any legal motor in any scenario. There's so many legal motors right now that a reduction in what's allowed will only affect the top level of teams; a team like 2667 would simply swap two CIMs for miniCIMs or another motor in a gearbox and be on their way. A team running a swerve drive and 3-4 additional mechanisms now requires a much bigger design change.
Aren Siekmeier
30-10-2015, 02:26
Remember that the likes of 254 and 1114 have always found their way around any such limitations. Those two teams, in 2010 when motor rules were still rather strict, built more sophisticated drive gearboxes with a power takeoff to power their climbing mechanisms, and still achieved very fast drives and climbers with the limits that were imposed. Other teams came up other ingenious ways around the rules to get high performance (gas shocks, etc.). Lower level teams don't have the fabrication capabilities or engineering help to compete with this.
This sort of argument comes up quite a bit. In general, relaxing the rules gives lower level teams more options to do what the high level teams were doing anyway, sometimes at great cost.
Remember that the likes of 254 and 1114 have always found their way around any such limitations. Those two teams, in 2010 when motor rules were still rather strict, built more sophisticated drive gearboxes with a power takeoff to power their climbing mechanisms, and still achieved very fast drives and climbers with the limits that were imposed. Other teams came up other ingenious ways around the rules to get high performance (gas shocks, etc.). Lower level teams don't have the fabrication capabilities or engineering help to compete with this.
This sort of argument comes up quite a bit. In general, relaxing the rules gives lower level teams more options to do what the high level teams were doing anyway, sometimes at great cost.
I think we're defining lower level teams differently; a team that is attempting to compete with the top tier but without quite as many financial or machening resources is what I would call a mid-tier team. I concur that relaxing motor rules does allow this level of teams to compete at a higher level than they previously would by giving them the "throw more power at it until it's fast enough" solution.
When I think lower level teams, I think of the 10-12 kid teams who's single mentor is their shop teacher. These team aren't greatly affected by motor rule changes as they generally have a kitbot + 1-2 simple mechanisms.
Jimmy Nichols
30-10-2015, 06:32
That's exactly how I feel. I'd much rather know now in a blog post than to read it in the rules.
Agree. When I started things like this didn't exist. There wasn't a blog and information like this wasn't widely distributed.
I just go the weekly email, I do feel that the timing of the blog post to the email could be better coordinated so that the information goes out together. So more teams get the info at the same time.
We use the BB RS540 for our swerve steering. I wonder if all BB motors are going to be illegal at a late date. With all BB motors listed as discontinued and new Planetary gear boxes from BB, they may have a new line for 2016. Time will tell. We have used the BB products for years and have liked the small light weight solution they provide. We design with in spec. The Vex pro planetary maybe nice but heavy and larger foot print.
For those who complain about motor controller prices, look at the other commercial shipping controllers for hobby robotics. These companies are providing high quality devices for a fantastic price. The Talon SRX with it's program ability is an unbelievable bargain compared to the other market options. Sub 50$ controllers is fantastic.
Jimmy Nichols
30-10-2015, 08:14
We use the BB RS540 for our swerve steering. I wonder if all BB motors are going to be illegal at a late date. With all BB motors listed as discontinued and new Planetary gear boxes from BB, they may have a new line for 2016. Time will tell. We have used the BB products for years and have liked the small light weight solution they provide. We design with in spec. The Vex pro planetary maybe nice but heavy and larger foot print.
For those who complain about motor controller prices, look at the other commercial shipping controllers for hobby robotics. These companies are providing high quality devices for a fantastic price. The Talon SRX with it's program ability is an unbelievable bargain compared to the other market options. Sub 50$ controllers is fantastic.
Our kids are designing a swerve and was getting ready to purchase the parts which included BB parts. I'm thinking Saturday will be looking at redesign or other motor options.
I'm very happy to see motor controllers going down in price over the last few years.
EricLeifermann
30-10-2015, 09:02
Very excited about additional motor controllers. A bit concerned about the lack of "vented" motors on the list. 550s and 775 had their issues with stall, but when done right, the air cool was nice for consistent performance.
Anyone have issues with BAG motors overheating in heavy competition? I would assume they get and stay hot similar to CIMS which is a bit concerning when you have back to back matches. Any experience?
We burnt out at least 10 on our practice robot before we switched them to different motors before out 1st comp last year.
Edit:
After several PM's I should note that we were not using the BAG's properly and that our systems last year were extremely inefficient with lots off loss to make up for, as well as several times the motors were stalled for an extreme amount of time.
We will continue to uses BAG's in the future as they are excellent motors when used properly(crazy how that works).
The roboRIO brownout schedule isn't harsh enough for you?
This.
If FRC goes back to a game which encourages vigorous interaction similar to that of 2014, expect "we had that match until we browned out!" or "we suddenly stopped moving, I have no idea why" to become a common refrain.
Richard Wallace
30-10-2015, 10:27
This.
If FRC goes back to a game which encourages vigorous interaction similar to that of 2014, expect "we had that match until we browned out!" or "we suddenly stopped moving, I have no idea why" to become a common refrain.
Many engineers would benefit from watching "Apollo 13" -- with special attention to the intense effort required to develop a critical procedure that satisfied the electric power constraint. When failure was not an option.
Many engineers would benefit from watching "Apollo 13" -- with special attention to the intense effort required to develop a critical procedure that satisfied the electric power constraint. When failure was not an option.
Agreed. This should be a huge consideration for all teams. However I worry that the teams who barely have time to finish a moving/functional robot are not going to have the resources to dedicate to power management solutions to avoid brownout conditions. Perhaps this is a topic for another thread, but we as a community will need to work hard to educate teams about this constraint.
marshall
30-10-2015, 11:05
Agreed. This should be a huge consideration for all teams. However I worry that the teams who barely have time to finish a moving/functional robot are not going to have the resources to dedicate to power management solutions to avoid brownout conditions. Perhaps this is a topic for another thread, but we as a community will need to work hard to educate teams about this constraint.
Agreed. We're going to end up with some mentors and students working on power management based around current monitoring from the PDP. Hopefully we can write a whitepaper about it once we've figured out how to implement it.
Doug Frisk
30-10-2015, 11:13
This.
If FRC goes back to a game which encourages vigorous interaction similar to that of 2014, expect "we had that match until we browned out!" or "we suddenly stopped moving, I have no idea why" to become a common refrain.
No, they're certain they know why. It's because the FMS is broken or the FMS hates them.
techhelpbb
30-10-2015, 11:36
Agreed. We're going to end up with some mentors and students working on power management based around current monitoring from the PDP. Hopefully we can write a whitepaper about it once we've figured out how to implement it.
I for one am very happy that the PDP now has this feature.
After so many years of this I am glad that a function that can help with this is actually legal on the robot on the competition field and basically included.
In past years any attempt by myself to determine these factors was actually limited by my ability to get someone to leave the robot alone long enough to do the measurements or by the fact that I couldn't legally put my gear on the competition floor. Now the tools are there one merely needs to use them.
sanddrag
30-10-2015, 11:50
Perhaps this is a topic for another thread, but we as a community will need to work hard to educate teams about this constraint.Can we start with someone providing the voltage at which the roboRIO (or anything else critical) drops out and resets?
Monochron
30-10-2015, 11:57
Can we start with someone providing the voltage at which the roboRIO (or anything else critical) drops out and resets?
Sure. Page 7. (http://www.ni.com/pdf/manuals/374474a.pdf)
Andrew Schreiber
30-10-2015, 12:01
Sure. Page 7. (http://www.ni.com/pdf/manuals/374474a.pdf)
And for folks who just want it and don't wanna download a PDF...
Can we start with someone providing the voltage at which the roboRIO (or anything else critical) drops out and resets?
Also listed here in the WPILib Docs (http://wpilib.screenstepslive.com/s/4485/m/24166/l/289498-roborio-brownout-and-understanding-current-draw)
http://i.imgur.com/rJcp9fg.png
marshall
30-10-2015, 12:09
I love this thread. Three responses with answers for the question in a row but all in different forms.
Doug Frisk
30-10-2015, 12:14
Also listed here in the WPILib Docs (http://wpilib.screenstepslive.com/s/4485/m/24166/l/289498-roborio-brownout-and-understanding-current-draw)
http://i.imgur.com/rJcp9fg.png
In theory it should work like that, but in practice more often than not the voltage drops so fast that none of the brownout stages really take effect and the radio just reboots.
I love this thread. Three responses with answers for the question in a row but all in different forms.
For Most drive teams:
12-7.3V = :)
7.3-4.5V = :confused:
4.5-0V = :mad:
For some:
12-7.3V = :)
7.3-0V = :mad:
I did not see this much last year (compared to previous years of CRIO or radio resets), but of course last year was a very different type of game.
Primary times I saw it occur were due to teams gearing robots too fast (say 40 FPS) or poor battery management/connections.
Most teams started angry with the field, and then once explaining/showing root cause were less upset.
mman1506
30-10-2015, 19:43
Are there any data sheets available for the SD540 controller? With all those pins it must have more than just pwm communication. Some dimensional info would be great too.
Monochron
30-10-2015, 23:56
Are there any data sheets available for the SD540 controller? With all those pins it must have more than just pwm communication. Some dimensional info would be great too.
Those are heatsinks actually. And I'm a bit worried by their proximity to that 3D printed mount though.
mman1506
31-10-2015, 01:24
Those are heatsinks actually. And I'm a bit worried by their proximity to that 3D printed mount though.
Are you sure those pins on the front of the case are heatsinks? They look like header pins to me.
Monochron
31-10-2015, 14:13
Are you sure those pins on the front of the case are heatsinks? They look like header pins to me.
Oh my bad :o
I believe that is a port for a ribbon cable, which they also sell. Not sure about the protocol used though, so I can't tell if more than PWM is possible.
Lil' Lavery
31-10-2015, 20:39
"Power gap" or not, there is still an embarrassment of riches when it comes to motor selection in FRC.
"Power gap" or not, there is still an embarrassment of riches when it comes to motor selection in FRC.
Please say that again, I remember the days of window seat, window glass and FP motors...
We are not a rich team and have invested in a variety of Banebots transmissions. It would be a huge waste of our funds and I imagine other teams funds to have to replace these transmissions.
Does anyone know how to interface an AndyMark 9015 motor with a P60 transmission?
We are not a rich team and have invested in a variety of Banebots transmissions. It would be a huge waste of our funds and I imagine other teams funds to have to replace these transmissions.
Does anyone know how to interface an AndyMark 9015 motor with a P60 transmission?
Yup! Here you go: http://www.andymark.com/product-p/am-2890.htm
Both the AM 9015 and the BB 550 are RS-500 style motors so they should have the same mounting features and shaft size. As long as you can get the correct pinion gear on the 9015 it should work.
MrRoboSteve
01-11-2015, 14:02
Per this post (http://www.chiefdelphi.com/forums/showpost.php?p=1482113&postcount=22) by NI, the brownout info in the NI RoboRio User Manual (http://www.ni.com/pdf/manuals/374474a.pdf) is incorrect, and the WPILib documentation (http://wpilib.screenstepslive.com/s/4485/m/24166/l/289498?data-resolve-url=true&data-manual-id=24166) should be considered authoritative.
Richard Wallace
01-11-2015, 16:10
Yup! Here you go: http://www.andymark.com/product-p/am-2890.htm
Both the AM 9015 and the BB 550 are RS-500 style motors so they should have the same mounting features and shaft size. As long as you can get the correct pinion gear on the 9015 it should work.
Using this kit with an AndyMark 9015 motor requires some care, because that motor has a knurled shaft. Refer to the layout drawing provided on the AM site; measurement over the knurls is larger than the pinion bore by 0.002 inch at the tolerance limits. Be careful to keep the shaft square to the pinion and to the tool you are using to press.
Also, the AM 9015 has a longer shaft than BB500. Not sure if there is enough clearance inside the P60 to accept that shaft without trimming; in any case the pinion will have to be pressed further so that the AM 9015 shaft protrudes, not simply flush with shaft as you would for the BB500.
Doug Frisk
01-11-2015, 16:17
I agree with Knufire. WARNING: You just woke up a geezer!
Back in my day, we didn't have no stinkin' 775 motors! Didn't have more'n TWO, count 'em, TWO, CIMs! Unlimited motors? HAH! We was lucky ta get more'n two of any one motor! And we didn't have all this selection of controllers either--all we had were Victor 884s! And Spikes! And don't get me started on the gearboxes! You think more restrictions means harder challenge, you're darn right, maybe it's ACTUALLY a challenge now! You young whippersnappers these days...
All right, back to seriousness... You get two drill motors, two CIM motors, two Fischer-Price motors, two Globe motors with attached gearbox, two window motors, and one van door motor. Build a robot that can play Recycle Rush. I can do it with two drills, one CIM, and one van door motor (and a couple of pneumatic cylinders). Won't be very fast, but I'm pretty sure that it'd be a second-rounder for consistency. (Hint: I've done it--2003.) By the way, that's the actual motor list from around '03-04 timeframe--we didn't get the second pair of CIMs until '05 and lost the drill motors to get it. And somehow, everybody showed up with a robot that--at least in general--ran, and most of them actually ran pretty well.
This whole "unlimited high-power motor" thing has been kind of... well, I don't know. It is what it is, but I'm thinking that it was about time for it to end. Maybe we'll get some contact back next year with the power dialed down...
I don't see any reason to limit motors at all. The battery and robot weight limits enforce a practical limit on motors. If someone want's to build a robot with 28 CIMs, I say more power to them. Or rather exactly the same amount of power as the team that uses 2 CIMs. Good luck operating more than 6 to 8 of them simultaneously.
I don't see any reason to limit motors at all. The battery and robot weight limits enforce a practical limit on motors. If someone want's to build a robot with 28 CIMs, I say more power to them. Or rather exactly the same amount of power as the team that uses 2 CIMs. Good luck operating more than 6 to 8 of them simultaneously.
The problem is that then somebody is bound to try to ignore those limits and complain all over the Internet that the battery/power distribution/control/whatever system isn't good enough and needs to be fixed. (Just like the limits on pit setup during load-in!) It's not that the system is lousy, it's that you don't know how to use it properly!
Sometimes, you just have to have easy-to-enforce limits in place to keep someone from hurting themselves.
Rahul and Richard:
Thanks for your comments!
Mark Sheridan
01-11-2015, 22:01
The problem is that then somebody is bound to try to ignore those limits and complain all over the Internet that the battery/power distribution/control/whatever system isn't good enough and needs to be fixed. (Just like the limits on pit setup during load-in!) It's not that the system is lousy, it's that you don't know how to use it properly!
Sometimes, you just have to have easy-to-enforce limits in place to keep someone from hurting themselves.
Just to argue the other way. It was kinda nice to stick with your favorite motors. Also, for 2015, I only used 3 CIMS and 2 550s , so next year I got to have another chance to go crazy with the motors.:D
It was kinda nice to stick with your favorite motors.
Heh. Reminds me of another "good reason" to make a change.
Ever notice how sometimes the GDC changes the size requirements, seemingly at random? Kinda makes you rework your favorite drivetrain to fit the new sizing. I seem to recall (way back in the day) rumors about rumors about teams pre-building a drivebase before the season, then putting manipulators on top. Next thing you know, the dimensions change...
Could be a move just to shake up everybody. That, and... *drumroll*
...FIRST has not announced a replacement for the 775s. Which could very well mean that there isn't one--or it could mean that they'll be springing it on us at Kickoff! Could you imagine watching Kickoff and finding out that there's a replacement motor in that class?
Mark Sheridan
01-11-2015, 22:46
...FIRST has not announced a replacement for the 775s. Which could very well mean that there isn't one--or it could mean that they'll be springing it on us at Kickoff! Could you imagine watching Kickoff and finding out that there's a replacement motor in that class?
Since FIRST is open to to adding speed controllers. I am willing to bet at least someone has been pitching a new motor idea for them to consider.
Since FIRST is open to to adding speed controllers. I am willing to bet at least someone has been pitching a new motor idea for them to consider.
That wouldn't surprise me one bit. I'd bet that if someone doesn't do it for 2016, there will be at least one pitched for 2017.
Ya know... There's a lot of folks who think brushless is a great way to go. The real question is, can you keep a brushless motor from stalling? And... is one in the same power class as a 775 at a reasonable price? (Actually, I'd bet the answer to the second question is "yes", and to the first is "it depends on what I'm using it for".)
AdamHeard
01-11-2015, 23:26
Ya know... There's a lot of folks who think brushless is a great way to go. The real question is, can you keep a brushless motor from stalling? And... is one in the same power class as a 775 at a reasonable price? (Actually, I'd bet the answer to the second question is "yes", and to the first is "it depends on what I'm using it for".)
Unless teams start the match with their motors spinning there is no way to prevent them from stalling.
Since FIRST is open to to adding speed controllers. I am willing to bet at least someone has been pitching a new motor idea for them to consider.
Just pitching a motor isn't sufficient. There needs to be enough donated for a motor (or other electrical component) to be made legal.
BBray_T1296
02-11-2015, 00:27
Unless teams start the match with their motors spinning there is no way to prevent them from stalling.
Ok... :rolleyes:
Keep them from obtaining an insurmountable load
mman1506
02-11-2015, 00:43
That wouldn't surprise me one bit. I'd bet that if someone doesn't do it for 2016, there will be at least one pitched for 2017.
Ya know... There's a lot of folks who think brushless is a great way to go. The real question is, can you keep a brushless motor from stalling? And... is one in the same power class as a 775 at a reasonable price? (Actually, I'd bet the answer to the second question is "yes", and to the first is "it depends on what I'm using it for".)
What's wrong with stalling brushless motors?
Ya know... There's a lot of folks who think brushless is a great way to go.
Brushless motors use completely different controllers (at least three wires to the motor, for one thing). So unless the list of legal motor controllers was partial, brushless motors would not be useful.
What's wrong with stalling brushless motors?
Magic smoke. Most of the brushless motors in the hobby market--a likely source for FRC-level motors--are designed to run at speed with light loading. If you put a heavier load on them, they have a hard time.
There was a thread about a year or two ago with a lengthy discussion on benefits/drawbacks of brushless motors.
There was a thread about a year or two ago with a lengthy discussion on benefits/drawbacks of brushless motors.
Linked here (http://www.chiefdelphi.com/forums/showthread.php?t=75542).
Mark Sheridan
02-11-2015, 14:28
Just pitching a motor isn't sufficient. There needs to be enough donated for a motor (or other electrical component) to be made legal.
A sales pitch is a broad term. I am guessing that your thinking of an elevator pitch or any other short form pitch. I was thinking more of the full blown sales presentation, where you have all the details on the table to discuss.
I agree to your point, a pitch without addressing supply chain and donations would make a poor pitch.
Will the PG71 Gearmotors offered on FIRST Choice be Legal? Both have a 775 motor on them:confused:
Mark McLeod
20-11-2015, 14:47
Everything on FIRST Choice is legal by definition. (or maybe not :-) the season rules, rule )
The 775 motors on the PG71's are not Banebot motors which are the only ones that have been discontinued and thus made illegal.
Peyton Yeung
20-11-2015, 14:49
Will the PG71 Gearmotors offered on FIRST Choice be Legal? Both have a 775 motor on them:confused:
The blog post said that the Banebots 775 would not be legal. It did not comment on the illegality of the AndyMark 775. In the past FIRST Choice components have always been FIRST legal.
Jared Russell
20-11-2015, 14:53
Everything on FIRST Choice is legal by definition.
So that digital multimeter is a legal robot part! :)
notmattlythgoe
20-11-2015, 14:55
So that digital multimeter is a legal robot part! :)
http://i3.kym-cdn.com/photos/images/newsfeed/000/657/039/7fa.jpg
Collin Fultz
20-11-2015, 15:02
Everything on FIRST Choice is legal by definition.
Mark -
I don't know that this is necessarily 100% true.
Going by the 2014 manual (http://www.firstinspires.org/sites/default/files/uploads/resource_library/frc/game-and-season-info/archive/2014/2014-game-manual.pdf) (I can't find the 2015 with the site redesign), only the motors listed in Table 4-1 are legal.
So a motor could be in FIRST Choice, but not in that list of motors. That motor could then be used on the robot, just not as a "motor".
-CF
AllenGregoryIV
20-11-2015, 15:14
So that digital multimeter is a legal robot part! :)
Seems perfectly legal to me. Not sure what you would use it for but it is legal. Actually it might even be legal as a
"Custom high impedance voltage monitoring or low impedance current monitoring circuitry connected to the ROBOT’S electrical
system is acceptable, if the effect on the ROBOT outputs is inconsequential."
I know first hand that this statement is incorrect.
" In the past FIRST Choice components have always been FIRST legal."
Everything on FIRST Choice is legal by definition.
Non-legal 2009-2014 control system components were in FIRST Choice last year.
Mark McLeod
20-11-2015, 15:56
Mark -
I don't know that this is necessarily 100% true.
Going by the 2014 manual (http://www.firstinspires.org/sites/default/files/uploads/resource_library/frc/game-and-season-info/archive/2014/2014-game-manual.pdf) (I can't find the 2015 with the site redesign), only the motors listed in Table 4-1 are legal.
So a motor could be in FIRST Choice, but not in that list of motors. That motor could then be used on the robot, just not as a "motor".
-CF
I concede the point that the manual does rule. :)
A good instance is the KOP white Clippard tanks that were explicitly called out by the 2015 rules as no longer legal despite having been KOP items.
Although, it does mean we shouldn't take FIRST Choice motors until the season's rules are issued.
I mislead myself thinking of this old Frank quote that admittedly doesn't apply since it is taken way out of the season in which it was Blogged:
- It’s safe to assume that if you see a robot component in FIRST Choice when it opens for “window shopping” on November 12th, it will be legal for teams to use in the 2013 season. Please don’t go all ‘lawyer’ on me with this one. Use good judgment. If you see a plasma cutter available in FIRST Choice, you should not think you’ll be able to put it on your robot. (Spoiler: There will be no plasma cutters available in FIRST Choice).
Mark McLeod
20-11-2015, 16:43
So that digital multimeter is a legal robot part! :)
Only putting a battery in it is illegal on a robot :)
Thad House
20-11-2015, 17:02
Only putting a battery in it is illegal on a robot :)
Actually, if I remember right, COTS devices are allowed to use their internal batteries...
Non-legal 2009-2014 control system components were in FIRST Choice last year.
There were no rules saying you couldn't use those parts. Just that they couldn't directly control the robot with them. If you wanted to put a cRIO on the bot and use it for camera processing then communicate to the RoboRIO you legally could.
Monochron
20-11-2015, 20:08
Will the PG71 Gearmotors offered on FIRST Choice be Legal? Both have a 775 motor on them:confused:
If I remember right, that AndyMark 775 performs very differently from the Banebots 775 anyway.
There were no rules saying you couldn't use those parts. Just that they couldn't directly control the robot with them. If you wanted to put a cRIO on the bot and use it for camera processing then communicate to the RoboRIO you legally could.
You could probably have gotten away with a cRIO, but I don't think you could have gotten away with an earlier PDB.
Michael Corsetto
14-12-2015, 10:50
Cross The Road Electronics (https://www.ctr-electronics.com/) has posted a detailed report of some Motor Controller Output Power Testing they preformed with the four main FRC speed controllers on the market:
Victor SP
Talon SRX
SPARK
SD540
Link to .pdf document here (http://www.ctr-electronics.com/downloads/pdf/Motor-Controller-Power-Testing.pdf)
Please take note of the test results on page 7. I'm very concerned about the SD540's performance, particularly that the SD540 appears to brown out at 9.5V.
2016 will be the year of the brown out...
-Mike
Thad House
14-12-2015, 11:24
2016 will be the year of the brown out...
-Mike
Programmers better bring their A game this year if teams want any sort of speed with 3 CIMs. Some very intelligent ramping and shifting code is going to be required for all the top teams.
Maybe someone who knows a lot about working with motor controls would be willing to do a white paper or something how how to limit current. Trying to find documentation online on how to do that has been impossible for me.
Jared Russell
14-12-2015, 11:46
Cross The Road Electronics (https://www.ctr-electronics.com/) has posted a detailed report of some Motor Controller Output Power Testing they preformed with the four main FRC speed controllers on the market:
Victor SP
Talon SRX
SPARK
SD540
Link to .pdf document here (http://www.ctr-electronics.com/downloads/pdf/Motor-Controller-Power-Testing.pdf)
Please take note of the test results on page 7. I'm very concerned about the SD540's performance, particularly that the SD540 appears to brown out at 9.5V.
2016 will be the year of the brown out...
-Mike
This is a very interesting study, and props to CTRE in making it easy to reproduce the test.
Assuming the motor controllers are all linear, we can calculate series resistances from the test data. Averaging all non-brownout trials gives me:
R(Victor SP) = 0.0042 ohms
R(Talon SRX) = 0.0050 ohms
R(SPARK) = 0.0075 ohms
R(SD540) = 0.0175 ohms
We can roughly model a stalled CIM as a resistor R(CIM) = 12V/131A = 0.092 ohms.
Now put our stalled CIM in line with each speed controller (so the total resistance is R(CIM) + R(motor controller), the resulting current is calculated by I=V/R, and the resulting stall torque is the ratio of this current to the CIM's nominal stall current of 131A using motors.vex.com data):
Stall torque (Victor SP) = 2.30 N*m. This is 95.6% of the motor spec.
Stall torque (Talon SRX) = 2.29 N*m. This is 94.9% of the motor spec.
Stall torque (SPARK) = 2.23 N*m. This is 92.5% of the motor spec.
Stall torque (SD540) = 2.02 N*m. This is 84.0% of the motor spec.
These are large enough differences from the motor spec (even in the Victor/Talon case) that designers will want to keep these numbers close by when choosing gear ratios.
And of course, keep these numbers in mind when choosing speed controllers this season. In some applications, it won't really matter which one you choose...in others, it most certainly will.
Jon Stratis
14-12-2015, 12:05
You could probably have gotten away with a cRIO, but I don't think you could have gotten away with an earlier PDB.
Well, you could have used that old PDB, powered from a 40A breaker on the new PDP, to power your custom electronics (but not speed controllers, etc). It wouldn't really be worth doing, as there are smaller and cheaper ways to get power to a collection of custom electronics, but it would be legal.
Ryan Dognaux
14-12-2015, 12:10
Programmers better bring their A game this year if teams want any sort of speed with 3 CIMs. Some very intelligent ramping and shifting code is going to be required for all the top teams.
With everything I've been reading about brown outs, I think we're just going to go back to the tried and true '4 CIMs on your drive' depending on the game. It just isn't worth the risk of being dead on the field in a match.
sastoller
14-12-2015, 12:20
Great paper! I found the read very interesting, with very informative, useful results to help teams pick the right motor controller.
A great addition to this experiment would also have been to include temperature measurements on the motor controllers after 30 seconds, 1 minute etc. I would also love to see results for the older Talon SR and JAG motor controllers since many teams still use these. One final addition would be to test several motor controllers of the same type to get an idea of the variation between controllers (is it 1% or 10% variation between controllers of the same type?).
My big takeaway from all this is that the SD540 is unnacceptable for use in FRC robots due to the brown-out issue. In addition, with it's high output resistance, it would no doubt, would get very, very warm in a stall condition. You can estimate the power that is turned into heat in the output devices of the SD540 to be nearly 50 Watts in the resistive load test 3, at 11.20 volts. With a CIM motor, the SD540 would be dissipating ~100 watts of energy as heat. I wonder how long it takes to melt (can someone test and post pictures please)?
It looks like the SPARK is a very good controller, for the price. It performs nearly as well as the two pricier alternatives. The downside for the SPARK is the form-factor.
James Kuszmaul
14-12-2015, 12:26
Cross The Road Electronics (https://www.ctr-electronics.com/) has posted a detailed report of some Motor Controller Output Power Testing they preformed with the four main FRC speed controllers on the market:
Victor SP
Talon SRX
SPARK
SD540
Link to .pdf document here (http://www.ctr-electronics.com/downloads/pdf/Motor-Controller-Power-Testing.pdf)
Please take note of the test results on page 7. I'm very concerned about the SD540's performance, particularly that the SD540 appears to brown out at 9.5V.
2016 will be the year of the brown out...
-Mike
Very interesting, although it would be nice if someone could do these tests with multiple of each controller (in case of either defective units or just generally varying units). In particular, I wouldn't want to judge the SD540 too much without confirming the results on multiple units.
Jared Russell
14-12-2015, 12:27
Programmers better bring their A game this year if teams want any sort of speed with 3 CIMs. Some very intelligent ramping and shifting code is going to be required for all the top teams.
Maybe someone who knows a lot about working with motor controls would be willing to do a white paper or something how how to limit current. Trying to find documentation online on how to do that has been impossible for me.
It would be awesome if the Talon SRX gets a firmware update that lets it do this (current limiting). It can already do ramping.
AdamHeard
14-12-2015, 12:33
It would be awesome if the Talon SRX gets a firmware update that lets it do this (current limiting). It can already do ramping.
Yup Yup.
I'd love this for FRC, and a few non-FRC applications I use Talons for.
notmattlythgoe
14-12-2015, 12:37
Yup Yup.
I'd love this for FRC, and a few non-FRC applications I use Talons for.
A continuous sensor option would be nice too. Similar to the continuous sensor option in the WPILib PID Controllers.
Thad House
14-12-2015, 12:38
It would be awesome if the Talon SRX gets a firmware update that lets it do this (current limiting). It can already do ramping.
Even if its not built in, since we can access all the current and speed data, wouldn't we be able to do this on the RoboRIO? It wouldn't be anywhere close to as fast of a loop, but it should be good enough, right?
notmattlythgoe
14-12-2015, 12:40
Even if its not built in, since we can access all the current and speed data, wouldn't we be able to do this on the RoboRIO? It wouldn't be anywhere close to as fast of a loop, but it should be good enough, right?
I haven't spent nearly enough time trying to track down the correct way to do this, but I would love to know what it is.
AdamHeard
14-12-2015, 12:50
I haven't spent nearly enough time trying to track down the correct way to do this, but I would love to know what it is.
Hopefully someone knows the answer to this.
If you're just running 4 Talon SRXs on the CANbus, nothing else and you're in a separate thread running your drive, what's the fastest you can run that loop and still get a fresh current measurement over CAN for each one?
Same question, but w/ PWM speed controllers and reading current over PDP?
Thad House
14-12-2015, 12:58
Hopefully someone knows the answer to this.
If you're just running 4 Talon SRXs on the CANbus, nothing else and you're in a separate thread running your drive, what's the fastest you can run that loop and still get a fresh current measurement over CAN for each one?
Same question, but w/ PWM speed controllers and reading current over PDP?
I know that the PDP only reads new currents every 25ms, or at least it was last season. Don't know if that changed. In addition, PWM updates at max every 5ms, so you couldn't go any faster then that even if you had a faster sensor.
The default status update period for Talons is 10ms. However I know that you can set it even faster. I bet you could do 5ms easily, and could probably push about every 2ms if you are careful with your CAN usage.
I would bet that is plenty fast enough, as your mechanical system probably won't react much quicker then that.
My big takeaway from all this is that the SD540 is unnacceptable for use in FRC robots due to the brown-out issue. In addition, with it's high output resistance, it would no doubt, would get very, very warm in a stall condition. You can estimate the power that is turned into heat in the output devices of the SD540 to be nearly 50 Watts in the resistive load test 3, at 11.20 volts. With a CIM motor, the SD540 would be dissipating ~100 watts of energy as heat. I wonder how long it takes to melt (can someone test and post pictures please)?.
sastoller : I think you need to brush up your Knowledge of "Switch Mode Operation" You cannot calculate the resistance just like R= V/I, in today's switching technology used everywhere. If you apply your theory to your cell phone charger your charger should be dissipating ridiculously large amount (120V-5V) * 1amp = 115W (120V input, 5 V output and 1 amp current) but is is not doing that. All it means is that it is not 100% ON but around 95% ON.
Cross The Road Electronics (https://www.ctr-electronics.com/) has posted a detailed report of some Motor Controller Output Power Testing they preformed with the four main FRC speed controllers on the market:
Victor SP
Talon SRX
SPARK
SD540
Link to .pdf document here (http://www.ctr-electronics.com/downloads/pdf/Motor-Controller-Power-Testing.pdf)
Please take note of the test results on page 7. I'm very concerned about the SD540's performance, particularly that the SD540 appears to brown out at 9.5V.
2016 will be the year of the brown out...
-Mike
Mike,
It is not brownout it is Seafty Feature, documents above says lockout due to Seafty feature,
I agree with this if you are going down to 8.2 V ( or even 10V ) you are seriously killing your battery.
Lead Acid battery do not like deep discharge, no matter what manufacturers say(deep discharge or what not), but they will not be same again if you discharge them down to 10.8V (1.8V per cell)
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