Re: TI and future Jaguars
 

I figured that had to be the case because the FIRST statements in the RFQ alluding to maintaining a diverse set of product can really only apply to the manufactures of the Victors. Unless there's some other company making approved speed controls.

As far as the issue of other markets. I think the modularity construct opens the door to that. FIRST can move in whatever direction they like, the rest of the product line can move in whatever direction it likes. We share only the common aspects where costs combine without major headaches.

In the end, as long as we limit ourselves to the existing power limits that FIRST wants any speed control will be stuck with only that market and only that sort of motor unless you can change that limit by swapping out the power section. I can see plenty of situations where the power limits FIRST requires are too high or too low.

In a straight up...hard and fast...quantity manufacturing situation the modular idea adds cost. There's probably no way we can make a modular speed control like this that will be on the cheap end of the R/C car spectrum. However, the value is in the flexibility. I'm sure that flexibility has a market as I've seen few unique alternatives. Also let's not forget that the Victor survives just fine apparently and it's not on the cheap end of the R/C car spectrum either.

As others have pointed out from the issues on the Einstein field, and through out the year at other venues, the whole expense of building something you don't absolutely *need* to survive is sort of lost when you drive blindly for cost. If a better radio, even $50 more expensive, would have prevented that situation I suspect the economics would be well on it's side considering the cost of even competing in just one competition. I know plenty of people that use electronic motor controls in hobby situations that would drool over some flexibility to mix and match, or more important convert their expensive model toy from entirely tele-operated to partially or completely autonomous.

It makes me wonder, however, when you spoke with TI did you describe the project as merely open-source or did you give them details? I do agree that if you suggest the manufacture of a electronic motor control with not much further inspiration from the Victor and Jaguar your market is severely limited, that's why I'm not really doing that here.

Re: TI and future Jaguars
 

I didn't discuss the details of your open source proposal with TI, just high-level.

I like your modular approach especially if the modules can find wider markets. But I wonder if we are slicing and dicing too much already. As you pointed out a modular approach is more expensive than an integrated one (everything else being equal).

I believe we could go the other way. That is a more flexible Jaguar. As we have seen in our technical analysis of the Jag (elsewhere on these posts), the power can easily be increased to 100A ++ just by adding another Mosfet per H-bridge leg, and setting different thresholds on the current sensing software. The BOM cost of that would be minimal. I was browsing through the 800 page Stellaris manual – that is a powerful and very well designed beast! It is made to run RTOS, abundant interrupt levels, it has an amazing brown-out hardware support – it seems the FIRST software image does not make much use of any of this. Therefore I believe one could make a Vic shaped Jag on steroids that would serve the 10A-150A market. And if it is just one SKU I believe the cost could be driven down to below $100. Further just like with the Vics and CRios, FIRST could obtain an additional discount for bona-fide FIRST users. But there must be other markets, and I would think there would be with such a flexible and robust unit. It will kill the Vic though.

On FIRSTs requirement of power control – why could that just be done by specifying the resettable fuse values for each type of motor? Then the judges would check that at inspection time.

Dean

Re: TI and future Jaguars
 

That's what we want! At a high level, all an FRC team wants is an improvement on the Jaguar, and the biggest complaints are the physical size and [apparent] current limit.

So, given the following two statements:

...it seems to me that we need to find the most direct (fastest) path to a Jaguar replacement. If not, the teams that have stocked up on Jaguars will have an unfair advantage over others (especially rookie teams).

On a side note: Dean, was this a typo?
I think you meant, "why couldn't that just be done..."

Re: TI and future Jaguars
 

I can see how having someone else absorbing the TI Jaguar as is might yield a higher current limit. The Jaguars with little change handle a higher current limit already (it's the FRC software in the way right now).

However, reducing the size of the unit, that's basically redesigning all the costly parts. Even the plastic molds for the cases would be in jeopardy. If you choose another purpose built enclosure you could be out $10,000 in just molds and light production just for the enclosures.

So basically what you want is the Jaguar, but not the Jaguar as you know it.

At some point you may as well build the modular speed control with a power module that is like the Jaguar, and an interface module that is basically the Stellaris running the FRC firmware.

Same headaches. Only change being it's modular. Yes it'll be marginally more expensive, but as Dean wrote, the Jaguar is not a money maker.

Re: TI and future Jaguars
 

Then their response was predictable.

The problem with integration is that you force the slicing of the bread just the way you offer. If integration alone was able to secure a large market segment they'd have achieved that long ago but when they did the knock-offs chewed it apart again.

As I've stated previously. I intend to move forward regardless of such an attempt. I think the Jaguar could be fixed. However, in doing so you'd be ignoring that TI couldn't massively sell the unit when it was totally open and sourced through DigiKey on any scale besides FIRST. As I've mentioned in private, custom robotics solution providers are not likely to simply accept the Jaguar (issues or not) as is. These users usually seek to lock in markets not open the markets up. Worse this isn't exactly a mil-spec product either so there goes most production aerospace and military application.

So even with the fixes, yes it'll satisfy FIRST, but I believe whom ever you convince to do that will be in the very same situation that TI put themselves in when they absorbed Luminary Micro. A new coat of paint with a target out of reach.

Why bother to measure current if you do that?
Also, generally self-reseting fuses rarely trip at the currents listed on them, short much higher currents can flow.

Even using the Stellaris and it's speed means that for a very, very short time a larger current could flow (it's just that the motors generally won't be able to make it happen).

Re: TI and future Jaguars
 

Since there is little in the way of actual schematics in this topic I should point out again.

If you take the Jaguar and look at the schematic. Look at the sections of it that handle the power. Look at the sections of it that handle the control.

Take the sections that handle the power and make them the power module.

Take the sections that handle the control and make that the interface module.

Stack them on top of each other.

You've just made the same modular electronic motor control I've been discussing and it's functionally (from the software perspective) the same.

What you just envisioned also has a smaller footprint.

So, I'm not following how redesigning the Jaguar...is all that much different from redesigning the Jaguar in a modular design. I realize it might be slightly more expensive. However, as I stated the original integrated result didn't exactly work as the designers intended on the sales end.

We bite nearly the same bullet. It's just that when we finish we can take the Stellaris off and use other things.

Some minor tweaks here and there but for the most part most of these circuits are not all that different from one another.

Re: TI and future Jaguars
 

Now twist what I just wrote in your head a different way...

Take this for example:
http://www.sparkfun.com/datasheets/R...8_H_Bridge.pdf

If this were put on a power module to be attached to an interface module that would be a big chunk of the power module all in one integrated part. Okay it's missing some of the features of the Jaguar and it's internally a different animal...but still you could make that module with discrete parts.

The idea is to turn the power module into the mass production component. For now that module could be discrete parts on a PCB. Later it could be a single part on a simple PCB if you could afford the integration.

The Stellaris is leveraged in IP. It's full of features that make integrating harder and the more you do, the more the costs to ever reach that scale will sky rocket.

This is no different than the power amplifier (PA) modules used in cellular phones or the RF modules using the D-Link AP. Heck it's no different than the parts from MiniCircuits in the old electronics magazines.

The guys that make cellular phones know what crazy features they want. They buy the 'magic' RF parts from companies and figure the rest out themselves.

Re: TI and future Jaguars
 

Thanks for confirming my speculation from earlier in this thread, that TI just doesn't see a business case where a profit could be made. Keep in mind that since it was just something they acquired as part of a bundle their decision to discontinue it was most likely made on the straight variable costs of manufacturing them and doesn't include amortizing the cost of development nor tooling.

Re: TI and future Jaguars
 

It probably really does not help TI that they source their own microcontroller if you think about it. What are they going to do mark up the price of it to themselves? :eek: (smacks head...I know a company that actually does do this...they'll be delisted from the stock market shortly).

Now think about what the FIRST RFQ demands. You have to use the Stellaris. So what do you think TI will charge you for it?

Yes to divide the Jaguar schematic as I posted earlier you'd need to buy the Stellaris from TI. However, you'd have leverage in a modular design. If TI makes it very expensive you can just swap it out for something more economical later.

Oh and if you're of the mind to make some silicon wafers to get around TI? Keep this in mind:
http://en.wikipedia.org/wiki/ARM_arc...#ARM_licensees

Let's consider this the Trojan Stellaris. You bring it in. It's all nice and pretty. However, it's filled with hidden costs.

Re: TI and future Jaguars
 

The modules are:
1. Power Mosfets
2. H-Bridge driver
3. CPU for fancy stuff and coms
4. Brown-out support (supercap etc that could be in a separate module)
5. on-board indicators (if desired)
6. Thermal management (for higher power systems, bigger fan, heatsinks, etc.)

In reality 1 & 2 would be one module (that is the Sparkfun link above).
3 - 5 would be the second module.
6 may be a selection of fans.


Have you seen the Raspberry Pi - a $30 Linux PC! that could give Stellaris a run for its money as the CPU module. Though we need an RTOS, but there probably is an open source RTOS that could be ported.

The problem we have is the lack of profits in this particular segment that would drive anyone to produce a Jag killer.

Maybe paying $150 per motor controller is not all bad if they don't break and we get to reuse them over many seasons...

BTW: I talked to a few teams that use other processors in addition to the cRio, and I was told the only thing FIRST cares about is that you run each motor control throughthe cRio so they can shut it down for safety. Otherwise you can mount a Cray on each tetacle of the robot. Is that so?

Dean

Re: TI and future Jaguars
 

Do not forget these probably need to be on the high power section or somehow optional to it:
A. Current monitor / voltage monitor.
B. Reverse voltage protection (optional and removable).
C. High side supply (driver could mean 2 different things)...please let's not use P-Channel MOSFETs for the high side.
D. Someway to identify what you just connected to the interface module.

Also we could use a SuperCap, or we could use battery backed static RAM, or just make sure it has a separate power supply interface for the interface module and the power module (let them find a battery to keep the interface module alive or take their chances).

The Raspberry Pi's prime interest to me is the very low cost. Other than that Gumstix, Cotton Candy, BeagleBoards and Pandaboards interest me as well. Along with the stuff at FriendlyARM.

Keep in mind also the Parallax Propeller is 8 processor (they call them COGs) each at 20MIPS microcontroller in a single chip with shared memory. That's 8 things you can do without sharing, scheduling or messing around. My current electronic motor control abused this nicely (why interrupt the processor for the CAN communications, just dump the adjustment data in the shared RAM and let the other processor pull it up when it's ready...no timing issues with flags and semaphores).

Given I'm offering to help offset the costs for a near production prototype, not really looking for an owner as much as contributors. They contribute a little here and there and then when it comes time for production they can use it as well. As demand grows for it, eventually we can start KOPing them if FIRST desires. At that point FIRST might chip in. In the mean time I won't object to people making them or having them made for them on an as need basis.

I think honestly we can make a PWM interface module and power module for less than or around $100 in small quantity.

The CAN modules? Pushing it a bit. Probably not with the Stellaris. Microchip PICs can do it. Atmel AVRs all the way to the XMega with some fiddling. The ColdFire 68k stuff no problem (even CAN2). The Parallax Propeller is a bit of a hack but it works.

Not entirely. Team 11 of whom I am one of the programming mentors did in point of fact field an AMD X2 dual core netbook on our robot this year. It was a full blown system without the display attached (I'll never see those tiny screws again BTW). It had an 32GB SSD. It was *just* under the $400 restriction. We connected it's ethernet port to the D-Link AP and used sockets to talk to Java in the cRIO with Java on the laptop (the students wrote a video processing application basically from scratch that used Video4Linux actually quite interesting). We did use the battery for the unit and all of that was legal and approved for field use at 2 competitions. We did remove the unit towards the end competition outings because of unrelated issues to what the driver's needed. It was connected to 2 USB cameras. One was 1080P resolution and slow frame rate. The other was VGA resolution and high frame rate (more than 30fps). It ran Ubuntu Linux.

The big trick was that it added weight to the robot (3lbs for the netbook) and no matter what anyone said including the Q&A last year I was very concerned we were gonna get told no at the inspections. Turned out great, just needed proof of cost.

I'll also point out again. If we endeavor to make the 'custom circuit module' the FIRST field shutdowns and limits would be honored by that middle module. A person could, if FIRST approves all that, take a laptop put a Parallax Propeller on a single PCB (they are usually used with USB for programming and debugging), make that PCB have places for 6 or 7 'custom interface modules' and then put 6 or 7 power modules on that. That would make one brain out of the laptop, with a USB interface to 6 or 7 electronic motor controls. Again you could do that technically that is all uncharted territory for FIRST to decide on. However for the hobby person they could remove the custom interface module and have essentially a single unit with a USB connector and places to connect 6 or 7 CIM size motors...just do some packaging. It's possible to make the entire control system for a FIRST size robot the size of a kid's lunchbox like that. (Just remember that something still needs to trigger the 'custom circuit modules' safety controls...so there would need to be something from FIRST to do that, software or hardware somewhere...but outside of FIRST...no such issue and no need for those middle modules).

Re: TI and future Jaguars
 

So the deadline is May 11th. Are you going to submit anything on opensource? I browsed through the RFP, they are cearly expecting the bidder to have staying power. I was surprised that they also expect passive royalties to FRC - I wonder if Vics and Jags have a % of sales that goes to FRC?

I got pressed into being the coach of our team - so I'll be busy with that...

Dean

Re: TI and future Jaguars
 

I have a question into the relevant people at FIRST about whether or not such a project needs to submit an answer to the RFQ under the circumstances.

Also, I have a question into my attorney about it.

The only way I could answer the RFQ currently would be to use my company interests to do so which I think sort of defeats the purpose of open-sourcing the project because I'd be, in effect, declaring myself the owner and sole source. It's not clear if I can openly declare myself source of last resort either.

We'll see.

Re: TI and future Jaguars
 

Posted in-line again because I can no longer edit my post above and further when I shift focus dividing the posts makes the entire thing easier to follow IMHO. So when one of you chooses to give me negative feedback about multiple posts in a forum with timeouts beyond my control again...well you have no one to blame except yourselves if you have administrative access.

That out of the way:

I've contacted FIRST KOP and they consider this project unlinked from their intent to have someone manufacture and support the Jaguar speed control nearly precisely as TI had done. So therefore the May 11th deadline in the original link of the RFP/RFQ does not apply to this community project. They would however appreciate as much documentation and information as we can produce as fast as we can produce it.

I've also indicated to them some of the basic details, such as 2 part modular design, one interface part, one high power part, an intention to make a PWM interface, a priority to make a CAN interface, the possibility of a 'custom circuit module', the goal to be able to produce a nearly finished prototype by the deadlines (which could be this year or next), the intention to provide the units outside of the KOP, the intention to have contract assembly houses assemble our parts on demand, and my personal intention to insure that at least 50-100 of them are available at the start of whichever season for delivery (regardless of existing orders for the units...if we start getting orders we can make whatever we need).

I've been running around between getting together data collection tools for Monty Madness, securing my time for Monty Madness and taking care of an emergency or 3. It's on my priority list this evening to get back to finishing up a site for this project so we don't burden ChiefDelphi.

Re: TI and future Jaguars
 

I think it is time to restate some basic principles here...
1. The resettable breakers are chosen to prevent fires on the robot. Nothing exotic about this, the current rating protects the wiring. What you choose to connect is up to you, the user. The breakers are not intended to protect a relay, a speed controller or anything else you put on the robot.
2. You must consider that these devices are going to be used by inexperienced students up to and including very experienced mentors. They must be designed to satisfy both groups with ease.
3. Any modular design you come up with had better be fully insulated, i.e. no exposed conducting surfaces.
4. Must use common wiring methods.
5. They must be addressable through the current hardware solution (PWM or CAN) and be capable of being commanded to make zero output from the field controllers.
6. This protection must also compensate for failures in the robot driver interface(s).
7. Above all, they must be easily inspected for conformity to robot rules.