New Speed Controller Announced
 

http://www.itnewsonline.com/showprns...p?storyid=4972

This article covers the new speed controller that will be in the 2009 Kit of Parts it looks really interesting features include current and voltage sensing.

Re: New Speed Controller Announced
 

ah man, no Victors next year ?

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Freaking awesome! This means we won't end up ripping victors off of old robots.

thanks, Vivek

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We may still be able to use Victors next year.

From the FIRST Technical Q&A

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I really like the feature set of these, but my primary questions are....

....how many do we get in the kit, and how much will additional units cost? ;)

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Wait sorry, are you SURE there's no VIC's any more? that would be good news for us, having two years ago named our robot Sparky after it successfully blew up 4, yes four, VIC's through out the season! large amounts of flying sparks and magic smoke!

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I wouldn't necessarily blame the HARDWARE for your magic smoke, as IFI's Victors have proven resilient for us time and time again, but per the article, the new controller does apparently offer a design that is more resistant to metal chips and such getting into the fan/MOSFET area. It also has color coded terminals to make wiring more straightforward and less susceptible to error.

The built in support for limit switch inputs is interesting.

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No it was not the VIC's themselves. We thought metal filings were getting into them and frying them, but when the two replacement VIC's we put in blew as well, we discovered that two of the four drive motors both had a shorting problem, which caused a surge, which was why the VIC's sparked. unfortunatly it was too late to swap motors, so we had two CIMs per side but only one was powered.

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Here is the Luminary Micro FIRST robotics site. http://www.luminarymicro.com/jaguar

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There's a website for it: http://www.luminarymicro.com/jaguar.
Seems like a prettied up vic with a few extras.

oops, what are the chances of that?

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These look cool! They also look expensive.

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They also look like they might take up more mounting space than an 884 array. We'll have to wait to get the dimensional info.

It's like old Pontiacs with the plastic body cladding (think Aztek) - I'd gladly do away with the gee whiz turbo look for a cleaner, more compact exterior.

The feature set still looks very promising, though.

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Are those black holes RJ45 ports?

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Yes, RJ-45 is the new connector style that will connect everything to the cRIO, via CAN communication.

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This is interesting news.

I am curious to see how they stack up against the Victor 884s, especially in the price, weight, size, and reliability/durability departments. Since the preliminary indications seem to note that both these and the Victor 884s will be legal this coming year, it would be nice if Luminary Micro began selling them before the kickoff date, so we could test them out first hand on previous/prototype robots.

Also, it's hard to tell from their CAD model, but where will the fan intake be? The top doesn't appear to be open, so does it draw from an opening in the back? Or are those little rib-like things in the front of the sides the air intakes? Depending on their airflow patterns, they may be easier to "stack" together to save space...

And for us mechanical nerds, it would also be nice if Luminary Micro posted CAD drawings of these online. Or at the very least, drawings of the mounting hole diameter and locations, as well as information on the counterbored area around these holes. :cool:

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Air intake is on the top; the rendering doesn't show it very well. There are exhaust ports on the sides and back of the plastics. The things on the front are for cable retention.

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you seem to know alot about these. Judging from your location what is your relationship with these controllers? do you have any pictures you can post? especially ones with a size comparison to a victor would be helpful.

Do you know the cost or when they will be available?

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those are awesome

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This sounds awesome -- however:

Why would we not be allowed to use the quadrature interface until "...Competitions after 2009"? It seems a bit silly to buy speed controllers with 32-bit ARM chips, and then choose not to utilize the advanced features enabled by the use of such a chip.

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It won't be so awesome for the teams who will have thousands of dollars in effectively useless Victors once FIRST transitions fully into the new control system.

I'm extremely concerned with the size of all the components of the new control system. All these pieces together are absolutely massive compared to what we've been using.

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I saw the new control system, but how big is the new speed controller?

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On the other hand, that may mean they will offer larger dimensions to fit all the new components in.

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I imagine there's ways to recycle some of the components.

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i doubt they would allow the size length and width to change do it still has to go through a doorway, but the height could change.

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One can dream...doubt it though.

I'd rather get a weight allowance than a size allowance.

It looks significantly bigger, based on the fact that there would be no room for an RJ-45 connector on the 884's, but the new controllers have the jack plus room to spare.

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Getting more weight allowance is not likely. It has been 148lbs the last few years (with battery and bumpers) because by OSHA standards, two people cannot safely lift more than 150lbs. If they increased the weight limit, you'd have to get 3 people to carry each robot.

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It's possible that the speed controller people and the control system people didn't get together in time to make it happen for 2009, and rather than throw more variables into what I can only assume is a somewhat already tested control system, they are only going to have basic use of the speed controllers for 09, and add in new features for the 2010 hardware. It may also just be a case of "the features are there, but the control system only supports v883 style control out of the box...experiment at your own risk." I'm sure we will find out more as things get closer...

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My concern, too.

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When they announced the '09 controller, I didn't mind letting somebody else fiddle with it.

But these motor controllers... if they do everything they say they do well, they should be a knock out. I've been working with/around CANbus for about three years now and it's always been very stable and VERY robust (you can, afterall, short the bus completely out and nothing will smoke).

They have this unit at the NI Week convention in texas. I asked my remote observation unit (aka my dad) to go take a look at this new speed controller and see what he could find... it ended up he handed the phone to the guy from luminary so, just two minutes after I first read about it here, here I was talking to the guy who makes em! :ahh: Funny ol' world, isn't it.

Anyhow, they don't have all the specs nailed down yet, but so far they do know the speed controllers take an input of up to FOUR MEGAHERTZ (meaning, if you put a 1024 count encoder on a CIM motor's shaft, it could run at it's free speed and the processor wouldn't bat an eyelash) on the quadrature encoder input.

Also, the chop rate on the drive's output is 16KHz so no more angry buzzing first robots, now we'll have a nice whine that's way up at the top of we human's audible range (could be annoying, but probably will be barely detectable. 32-bit resolution over the duty cycle range from full on to full off, linear accross the entire range with 1-bit resolution (meaning minimum throttle is 0.00000002% instead of 10%).

Oh how I wish we had these speed controllers this year! Our autonomous would have been SO much smoother!

-q

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When I was at the Championship, I talked with the people extensively about the new control system. They said that there was a very good chance that we will still be able to use Victors on our robot.

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eBay! Just because Victor 884s might not be allowed in FRC in future seasons would not mean they've lost all use. They are really good speed controllers, and there are always other people (especially Battlebots community) who would buy them.

Gone are the days of giving the electrical and controls people a cubic foot of space and telling them to make it work... :rolleyes:

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Obviously your mechanical people have been spoiling you. They have been giving you far too much volume ;)

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I would be inclined to say that these controllers use the standard R/C PWM wiring scheme the Victors employ, seeing as a) the digital sidecar for the new system has standard PWM outputs and b) the PDF explicitly states it uses the standard R/C PWM servo interface.

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Since when is big the new small? First the radios, then the maxi breaker panels & distribution blocks, then the new control system, and now the speed controllers...

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I have been estimating 6 lbs and about 1/2 cubic ft. for the control system alone. You can back into the size from the picture knowing that the pin spacing on the header is 0.1 inch or judging the two RJ 45 jacks. I am guessing that it is at least 1/2" wider and 1" longer than Victors.
16kHz is still audible to students and I can tell you from experience that 15,734 Hz is annoying to anyone under 50 and some over 50. I question the choice of switching frequency vs. the inductance of the motor windings though. Testing will confirm this.

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Maybe more teams will use the old Victors, they are still available.

It's beginning to look a lot like Christmas...
 

The flyer (pdf) I read said 20kHz. Am I mistaken?

As to claims of linearity, that depends on what you mean. The output may actually be very linear, but the system need not respond in a linear way.

My experience in automotive systems is that when you go from low PWM freq (100-400Hz) to higher PWM freq (10-20kHz), the motors do not respond the same, especially at low duty cycles.

For example, if, in order to get a system moving, we needed say 20% duty cycle at 100Hz, we would need to bump the duty cycle up to 30-40% at 10kHz PWM freq.

This was very puzzling but we eventually attributed this our mechanical system's time constant. At 100Hz, the mechanical system's time constant was such that the system had time to react during a single PWM pulse -- These "full on" pulses provided a kick to get the motors and gears turning. At 10kHz, the system can only react to the average not the individual pulses, so it required more on time to get things rolling.

It does not say in the flyer but I hope that the H-bridge is configurable in ways that are feedback loop friendly. What I mean is that you can drive motors via an H bridge in several ways.

1. ON = 12V, OFF = Open Circuit
2. ON = 12V, OFF = MOTOR LEADS SHORTED
3. ON = 12V, OFF = -12V

#2 is very nice for feedback control of large arms for example.
#3 sounds very strange at first, but it can provide some very nice control features as well (thought it can be tough on the electronics) in this case

• "OFF" for the motor is accomplished by outputting 50% 12V & 50% -12V.
• "50% Forward" is accomplished by outputting 75% 12V & 25% -12V.
• "25% Reverse" is accomplished by outputting 38% 12V & 42% -12V.

As I said, it seems strange but it has some very nice behaviors. This type of control is called locked anti-phase motor control and I discuss this issue at length here

Once they implement CAN, I hope that they also consider some other control friendly strategies:

• using current messurements to allow for velocity (and even position) control without the use of encoders or other sensors. I discuss this here: What Dr Joe Wants for Christmas... (Man, I love referencing myself ;-).
• implementing PID control onboard the speed controller (send it your gains and from then on just give it a desired position -- let IT figure out what the PWM outputs should be)
• Diagnostics, diagnostics, diagnostics. At a minimum teams will know if a speed controller has become unplugged -- I guess that feature alone would have changed the outcome of about 20% of the FIRST tournaments ever held. But open your mind a bit and you can imagine diagnostics that tell you if your motor is overheating, if your mechanism is binding up, if your wheel treads need to be replaced, etc. etc. The mind reels at the possibilities.

It is only August, but it is looking more and more like Christmas to me...

Joe J.

Re: New Speed Controller Announced
 

I notice that this press release comes from Luminary Micro, and not from FIRST. They are bold enough to announce that they "will be included in the FIRST Robotics Competition's (FRC) official Kit of Parts (KoP) and distributed to over 1,700 teams in the upcoming 2009 international FRC." This "announcement" has not yet been acknowledged or confirmed by FIRST. But I have heard rumors that the content for the 2009 KOP, and the associated rules about what is legal to use on the robots, have not yet been finalized. Therefore, I would surmise that this announcement may be a bit premature.

I have heard tales of some members of the GDC that are devious enough to pull an item out of the KOP specifically because the community got unauthorized advance knowledge of a part, and started to do pre-design and pre-build work before the season officially started. After all, wouldn't it be interesting if the entire community got all spun up about a rumored new "capability" that was then never actually included in the KOP? That would be an excellent way to divert their attention away from what was actually going to happen.

Nah, something like that would never happen. :rolleyes:

-dave



.

Re: New Speed Controller Announced
 

I weary of the new system just because it is new, but a lot of these features are very interesting to me. I'm really interested to know more about the sensor feedback.


Brandon, can you ban his account? Please....?

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One thing that I noticed (and do not like) is that there is no ventilation for the drive MOSFETs or etc inside. Driving 20amp motors will get them warmed up and those look like they will be nice and toasty.

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Joe,
I was referencing a previous post with the 16 kHz. At this and higher frequencies, the combined inductance and series resistance will produce a low pass filter that will serve to limit rise times and produce triangle waves instead of the the expected square waves. Glad to see you back on the forum.
Perhaps Richard, if you are reading this, can give us a handle on motor winding inductnce. I would think it would be pretty high, on the order of 100 mH. I won't be able to do any measurements for several days.

Re: New Speed Controller Announced
 

While the new control system (including these speed controls) is more capable than the old one, the increase in physical size is a lot. We would not be able to comfortably fit these components on any of our previous four robots.

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Where did you "notice" this? It's contradicted by the Jaguar's reference sheet, and the ventilation grille on the top is recognizable as such in the posted image.

Re: New Speed Controller Announced
 

From the tech at the Luminary booth here at NI Week.....

-full current sensing and feedback for position control, when they unlock the feature in '010
-onboard PID, you tell it the constants and it goes to work

The unit has a cool limit switch feature also built in. you can wire a limit switch directly to the esc for both directions of operation as a built-in software stop.

The standard pwm connection still applies for now. the CAN interface is either disabled or now allowed for our use, though the demo unit they were running was linked up via ethernet cable. looked pretty slick.

Woody said we'd be able to use victors this season to carry us through the transition. The most exciting news, is that both the FIRST rep and the NI rep said the price point for the Jaguar was going to be significantly less than the victor....."we'll be happy" were his exact words!

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Any chance you can post some real photos of it with something for scale (a dollar bill)

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I'll try to get some tomorrow.

It is slightly larger than the victor. The demo unit they used at Nationals had an NI protype of the device.

Compared to the cRIO the jaguar is only slightly different. They mentioned many times during their presentation that the new larger size was part of the game challenge.

Also interesting, everything here is Solidworks. they've given many impressive demos of labview directly interacting with Solidworks models. I'm not sure how this will play out in the future, since Autodesk is such a major FIRST supplier.

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Working from the picture on the flyer, (and by no means a scientific measurement) I get 3.6 x 2.4 inches. The Victor is 2.7 x 2.2 inches for comparison.

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I scored a few comparison pics of the Jaguar next to a Victor....I uploaded them. I'll link them over as soon as they're approved.

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Was anyone dressed up in a purple suit saying, "It's all part of the plaaaaaaaaan", followed by some derisive cackling?


"Yes, I'd like to Super Size my speed controller combo and add a jumbo distribution block, please."

"You want fries with that?"

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Pictures are up.....OMG that thing is HUGE




HUUUUUUGGGGEEEE Rochester HUUUUUGGGGE (anyone from upstate NY will get that reference)

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If you flip them on there sides and then stack them horizontally, it might not be that bad.

They do sort of dwarf the victors.

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Why is it that every single piece of the new control system seems to be twice the size (or more) of the old stuff? IFI's stuff was more-or-less 10 years old - you'd think that the advance in technology would make things smaller, or at least the same size considering there's more powerful stuff inside.

How much functionality are teams going to have to sacrifice to make room for all the extra space needed by the new stuff? I know several of the robots we have made in the past would simply not be possible now (2001 for example).

Another thought: with the increase in functionality offered in the new controllers I hope they're getting a very serious and thorough testing. Adding that much complexity and software to something that's as safety-critical as a speed controller definitely increases the risks of bugs. Having a bug in something that's supposed to turn OFF the motor when the robot is disabled would be scary... I think a lot of people have taken for granted that with IFI, when you disable the robot with a disable switch it is OFF. Personally, I'm not going near a robot w/ the new control system unless it is physically powered-off until I gain enough confidence that it works the way it's supposed to. As a software guy I know all too well that trusting software for my safety can be a dicey proposition.

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Yeah, its almost Pizzone sized :D

So are PWM's optional now? LAN cables wouldn't fall out as much. Thats a major plus IMO.

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LAN cables weigh a lot more and take up more space (I sense....a theme).

Plus you'd still have the problem of coiling the extra cabling if you didn't have a DIY RJ45 kit.

Dab o' hot glue for the win.

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For 2009, you have to use the PWM ports. The can bus (with the RJ-45 connectors) will not be available until "future years" which probably means 2010 because the CAN module that they have for the cRIO won't be in the kit for 2009.

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Wow, judging by the pics, that thing is bigger yet than I imagined. Besides, what's with the round edges? We're not going for looks here, and square things just stack much better.

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Here is the video from the Demo NItro robot at NI week 2008 and jaguar components on the MentorSearch Channel.

http://www.youtube.com/user/mentorsearch

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I didn't realize the Victor supported SPI. WoW! :rolleyes:

... cool video anyway. Thanks.

NI is spending a lot of money promoting the Jaguar if it's not definite it will be included in the KOP :eek:

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If you dig around the MentorSearch Channel you can find a few more interesting videos about the Jaguar and VXworks

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This is a great video. Things I noticed:

• It would be nice if the Brake/Coast feature was a switch and not a jumper. (People lose jumpers)
• CAN looks very powerful. I love how you can daisy chain Jaguars together. This will keep wiring simple.
• The Jaguars run on 12V (from the literature). Can you assume they know the robots electrical system will be 12V in 2009 with some sort of 24V transformer for the cRio?

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• The advantage of making it a jumper is so that you can connect it to one of your digital output ports and control it on the fly. Sometimes teams will use brake mode in autonomous and coast in user control, if that is what the drivers prefer.
  
  Quote:

  CAN looks very powerful. I love how you can daisy chain Jaguars together. This will keep wiring simple.

  I agree, this will be very slick. Unfortunately it won't be available the first year.
  
  Quote:

  The Jaguars run on 12V (from the literature). Can you assume they know the robots electrical system will be 12V in 2009 with some sort of 24V transformer for the cRio?

They are aware of all the features of the new control system, and since all the motors are going to be 12V (I guess I can't say that with certainty, actually) it would make sense for the speed controllers to have 12V input.

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I wonder if teams will be able to use the CAN network even if it isn't supported. All you would need is to buy the CAN module for the rio and hook them up, unless they are hardware disabled this year. I wonder who the first team to do this will be. My money is on 111, or 330.

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Here's a good demo of the Jaguar. While it's clear from this that we won't use the CAN in 2009, no mention is given of the sensor support (Hall and encoders) mentioned in the press release.

http://www.youtube.com/watch?v=2ikgguMKqBk

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I asked about this at NI Week yesterday and they said that the FPGA image will not support the CAN module, and since you aren't legally allowed to change the image for 2009, so I guess you could do it, but it wouldn't be worth the effort since you'd have to get rid of it for competition anyways.

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I still can't think of a good reason for disabling it. If we can't use CAN then all these really end up being is really large Victors.

Also, since I am new to FRC, I am guessing it would be illegal to strip off the silly plastic case on these. Might help weight and size (as well as cooling!).

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The only reason for disabling it is to reduce complexity since getting the new system is a huge change on its own. They wanted to finalize the FPGA image early to allow ample time for testing, and didn't have time to include support for CAN.

So, yes, they are really large Victors, but there's still four advantages that will apply for 2009 -
1. lower cost than the victors
2. better protection from metal shavings getting inside
3. higher frequency output to eliminate the "whine" that all FIRST robots with Victors have, usually most noticable at low speed.
4. built-in limit switch control to stop motor from going one direction or another

Yes it probably will be illegal to do that. I agree it would help weight and size because the PCB inside is at least 1/4", maybe 3/8" smaller than the plastic housing on all sides. That would add up to a lot of space savings. But it really isn't worth the risk of getting metal shavings in because there's no protection.

I do know they did extensive thermal testing to make sure the fan and ventilation was adequate and ran the controller well above its designed limits, and didn't fry anything. It is designed to automatically shut off if it reaches 60A or above for more than 2 seconds. It takes a second or two to cool down, and then will turn back on.

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Eh, even with that, my team will be using victors in place of these for 2009 (as far as it is allowed). I can already see the size and weight savings being beneficial.

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That seems logical, assuming you already have a supply of Victors lying around. For the teams that don't have a supply, it would be more difficult because the KOP will come with Jaguars, not Victors. They haven't said how many, but I would guess 4 since that's the usually number of motor controllers included. So that's an extra $460 for 4 Victors.

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I am going to wait for kickoff to make this decision to see if they are actually in the kit also how much they are each. With a ton of untested hardware this year it may be worth the extra money for victors just to know you have something that is bulletproof.

I think I must reiterate what Dave said, that FIRST hasn't said anything about these yet. While I am sure that there is some relationship don't get to excited or bent out of shape till you see them in your tote. Considering that they are hyping these things up without having the production cases on them yet doesn't instill much confidence.

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It wouldn't make sense to have the sensor inputs active, without a way to do anything with them (ie send them over the CAN bus).

If done correctly, moving the limit switch handling to the speed controller will increase safety, as that functionality is small, easy to test, and (hopefully) unable to be overridden. I would be much more scared if all of this was built into the core operating software.

I can't name all the times we've had a software logic error which rendered limit switches or another safety device ineffective.

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They better have a free upgrade service for the new software. I don't want devices in the KOP that require me to purchase something (in this case at least an emulator) to upgrade their functionality.

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That's Dave's point... what process is in place to qualify the software? Will the software pass a safety board?
With IFI's system and the Victor I feel comfortable putting my finger in a pinch point if the system is in the disabled state. I will not for a couple years with the Jaguars.
... the million dollar question for me is why Luminary Micro would like to step into the motor control business? What do they have to gain given their current product line? I don't understand.

Re: New Speed Controller Announced
 

Perhaps someone can find this out: If we go wild on speed controllers for 2009, will we be able to enable these features in 2010 when it's the night before ship day and we need just that one extra speed controller?

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Luminary is not getting into the motor control business. They are in the motion control controller business. The Jaguar is essentially a reference design that shows professional EEs how easy it is to create a strong motor control algorithm using their processors.

I'm an electrical engineer, which means I have sales reps and vendors trying to sell me on their product lines all the time. Usually this involves them bringing in food in exchange for an hour of our listening time. Invariably, they bring in demo boards - power points just don't cut mustard. I'll bet you lunch that their sales reps will be have these in their demo boxes by February.

I doubt very much they are doing this for the money. They are doing this for the same reasons NI is:
1) They get the FIRST message.
2) They get targeted effective advertising to their core market.
3) They know they'd be stupid not to.

Re: New Speed Controller Announced
 

I'm not exactly sure I understand the question, are you asking about availability of the Jaguars? As far as I know the current plan is to distribute them via Digikey, for any controllers needed on top of what's included in the kit

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Mike,
The power distro has a 12 to 24 volt convertor built into it to run the CRIO.

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The speed controller FW will upgradable via CAN. So any features currently disabled because of missing SW/FW are field fixable.

In response to another posted question. FPGA updates on the cRIO are done via a PC based tool, which is free.

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I agree. If you look at their demonstration boards the only motor application that is missing is a regular DC motor application which is generally the most trivial. I don't know if they plan on making money with the Jaguar. Some companies adopt a loss leader approach to these products while others tend to price their products to correspond to the cost of manufacturing.
That is not good. Digikey tends to mark up the prices from the manufacturers prices. Not by that much but it is a little irritating to pay ten dollars more.

Re: New Speed Controller Announced
 

I can't comment on Digikey's markup, but do want to point out that for Canadian customers Digikey ships from within Canada, meaning that each order saves about $35 in brokerage fees relative to companies that ship UPS from the states. (Yes, pretty much EVERY order of robot parts out of the USA goes through a brokerage firm, and you can end up paying a $35 brokerage fee on a $10 part.) They also bill in Canadian dollars, which makes some of the book-keeping a bit easier. Their delivery time is much faster for Canadian customers than USA-only suppliers, unless you feel like spending $50-$100 on international express shipments.

I would be delighted to see Digikey as part of the FIRST supply chain... so long as they keep these controllers in stock north of the border as well!

Jason

P.S. And a big "thank you" to Andy Mark for shipping from within Canada and eliminating brokerage fees.

Re: New Speed Controller Announced
 

Not cool. Not cool at all!:p

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Being a controls guy who was converted from Mechanical, can someone explain what "CAN" is and why it is so beneficial?

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Intelitek Uses CAN on our industrial line of CNC products.

Short Version: CAN is basically a serial communication standard that allows devices to be daisy chained.

Controller -> Device -> Device -> Device -> Device -> Terminator

Long Version: http://en.wikipedia.org/wiki/Controller_Area_Network

Re: New Speed Controller Announced
 

CAN == Controller Area Network. It's a multicast serial network protocol and bus specification. In this case CAN 2.0A/B, which is a little more flexible and faster. The Jaguar flyer declares a 1Mbit/s rate, but doesn't bother us with piddling details like what application protocol they're planning on using.

In practical terms, it's a 3-6 wire bus that you'd connect all of your speed controllers and other CAN devices to, either daisy chaining through devices or branching out from hubs, but avoiding loops. Then the cRIO would talk to EVERY device on the bus, sending it commands and receiving data back at a reasonably good data rate. It's all digital, so you worry much less about noise mucking with your analog signals or interrupts or speed controller frequency drift mucking with your commands to the motors. Plus, you could get feedback from the speed controllers if they're equipped to sense current, etc.

Primary downside would be that you're now running (probably) 5 wires to each speed controller, sensor, etc. Plus every new device on the network reduces the speed you can talk to the others. And finally, bus termination, addressing, and a host of other details become pretty important to keeping communication fast and stable.

If you want a slightly technical description in more MechE terms, a CAN bus is something like if you had an intercom system in your house, where your only option was to talk to all the stations at once. Since it's a multicast bus, you have to announce just who your messages and replies are intended for so a conversation would go something like: "Hey Tom, I need your credit card info to pay for this spiffy new FRC controller." To which you might reply, "Hey Kevin, I'm still broke from the last FRC gadget you had me pay for!" And so on.

Also, since it's a multicast bus, you might get two people trying to talk at once. This could obviously cause confusion, which CAN solves in a few different ways, depending on the physical implementation. The simplest is that some messages have a higher priority than others and basically talk over the other messages. If a speaker hears someone talking over them, they wait till the end of that message then try again. There's various other methods, but the upshot is that everyone gets their say eventually, but some people have a higher priority than others.

The downsides I listed above equate to problems like trying to talk to two people with the same name, throughput problems if 40 people are all trying to talk at once, and physical problems like someone falling asleep with his finger on the Speak button and snoring over everyone. Of course, it's still better than the tin-can phones and telegraphs we're currently using.

Response to Adam:
Other network topologies are possible if you're using repeaters. Industrial versions can admittedly get a little pricey, but if FIRST is making us a bunch of other stuff anyways it'd make some things a little easier.

Re: New Speed Controller Announced
 

CAN is why it takes so long to feel comfortable driving a hybrid electric vehicle.

Nothing is connected to what it controls! :ahh:

-q

(oh yeah and it carries control signals about airplanes and farm equipment, along with the occasional power plant, generator set, etc... the company I've worked for for the past three summers makes (among other things) CAN enabled industrial control modules)

Re: It's beginning to look a lot like Christmas...
 

Through the private beta test channels, I asked these types of questions. They just released some test data publicly, which show a very nice linear response without any slow starting when driving a CIM motor. http://forums.usfirst.org/showthread.php?t=10182

Re: New Speed Controller Announced
 

I'm bumping this thread to link to the Luminary Micro's Jaguar Motor Controller Characterization thread on the First Forums and attaching a copy of the excel sheet (for those who are not FIRST Forum members). This is obviously very important data for everyone to consider when controlling their robot and I am glad they can provide it to us so early in the process (thanks Joe Hershberger ).

EDIT: I started writing this post before Joe Ross posted (beating me to it) but got side tracked. I guess we think alike for where to post this data in this older thread.

A few comments: I am impressed with the linearity of the CIM Speed vs Pulse Width. However, I am not sure (and not qualified to speculate not a ME) how well this will linearity will translate to speed of a motor under load (normal 4 motor drive of 130 lb bot). In my experience, at lower powers on the victors the drive motors just hum so will the jaguars just hum (depending on gearing obviously) for a the lower portion of these graphs. Maybe a fast rise like the victors is better in this case?

Re: New Speed Controller Announced
 

The linearity (assuming that it holds under load) makes it easier to build a table replacement for a custom response curve. Define the dead zone, fast rise to first motion, low slope at low speed for precise control, steeper slope to get to full speed.

Re: New Speed Controller Announced
 

Brian, Joe and Dr. Joe,
These functions are more attributable to the segment spacing of the commutator vs motor speed vs PWM switching frequency. Each motor type will respond differently and the overall inductance of the windings will play a part as well. Often linearity is affected as much by the mechanical frictions within the motor and the load at low RPM as with any of the other variables. The "hum" in motors controlled by Victor controllers, I believe, is directly attributable to the low PWM frequency and short pulse duration. I have often observed teams who failed to calibrate the controllers and were supplying minimum pulse widths to their motor at rest. These short pulses were sufficient to bump the motor armature but could not supply enough current to overcome the friction in the drive train. One of the advantages to using 12 volt PWM is to get the motor moving while giving some speed control at low RPM. I expect the higher switching frequency to produce less hum in future systems. The upcoming season will give us some data on linearity under real world loads, stress on the motor in forms of heating, brush and commutator arcing, RF interference, etc. It will be interesting.

Re: New Speed Controller Announced
 

Hey, he was a sponsor of team 1507 for two years...

:)

Re: New Speed Controller Announced
 

According to an NI video on the RIO, its dimensions are: 11.3" x 3.5" x 2.3", and it weighs 2.2 lb.

It will also withstand a 50g impact, so it sounds like it could do double duty as a bumper.:)

Re: New Speed Controller Announced
 

As the Chief Inspector, I feel obligated to point out that bumpers (per the 2008 robot rules) are only allowed to weigh up to 3 ounces per inch of length. Unfortunately, the cRIO weighs 3.12 ounces per inch.

Sorry. You can't use the cRIO as a bumper. ;)

Russ

Re: New Speed Controller Announced
 

http://www.youtube.com/watch?v=2ikgguMKqBk

I'm very distressed because they're very large. Victors were tall but didn't have a very large footprint.

Jaguar footprints seem to be more than twice that of Victors'.

Re: New Speed Controller Announced
 

Here is the key to relieving your stress. Consider the size of the Jaguar as just another design constraint. :rolleyes:

Re: New Speed Controller Announced
 

Just for the heck of it, I found the specs for the speed controller that was used before the Victor, the Tekin Rebel. It is 1.8x1.4x1.1 inches. That makes the Victor (2.7x2.2x2.1 in) approximately twice the size of the Tekin Rebel.

I then searched the 1999 and 2000 forums of chiefdelphi, and didn't see a single person complaining about the size of the Victor.

The Victors were so much better then the Tekins that no one cared that they were bigger. Based on the data and specs of the Jaguars, I think they will be so much better that in 2 years, no one will care that they are bigger then the Victors.

Re: New Speed Controller Announced
 

from what i can tell (i'm mostly mech) the pro's of this new controller should be a big enough improvement for the extra space to be worth it to design around. The response and smoothness that apparently is there will be really nice for drivers as it should smooth out the low speed precision maneuvers that are often required.

(i still love victors though)

Re: New Speed Controller Announced
 

The jump to from the Victors to the Jaguars is small compared to the change from the Tekin to the Victors. The Tekin's used to constantly suffer from spontaneous combustion, it was extremely frustrating how often they would go.

The Victors have been very solid throughout their tenure. For non PID related control I don't think we really need much more. But, for control loops the Jaguars sound like a godsend. Allot will also depend on the cost of one vs the other.

Re: New Speed Controller Announced
 

Ok. Now you have me interested. Could you explain your logic?

Re: New Speed Controller Announced
 

The Jaguar has several interesting features aimed at tighter control loops. Unfortunately, only some of these will be useable this year.

1) The speed vs input command is linear. The Victor is highly non-linear, which prompted many teams to wrap a linearizing function around it.

2) The update rate is faster.

3) The chop rate is much faster.

* Features not yet accesible to teams *

4) The processor in the Jaguar is about an order of magnitude more powerful than the entirety of the old control system in terms of raw math throughput.

5) Direct quadrature encoder input

6) Analog input - for POTs?

7) True voltage control - This translates to direct speed control.

8) True current control - This translates to direct torque control.

9) High speed serial (CAN) communication to the cRIO which will allow you to send higher level commands

10) On-board PID loops.

http://www.reuters.com/article/press...08+PRN20080805

I'm excited.

Re: New Speed Controller Announced
 

Not to mention:

- integrated limit switch inputs
- instantaneous current monitoring (this feature would have saved our team several $100 Victors)
- instantaneous temperature monitoring

Re: New Speed Controller Announced
 

It looks like we are going to get 4 jaguar's in the kit, and their cost is 92.50 before the FIRST discount.