Re: TI and future Jaguars
 

I recall hearing of something similar happening once...
Maybe even twice.

Sure, these might have had more time, but with more people, it could be expedited. The biggest obstacle is communications. The production could occur at several different locations, but distributing the work load based on ability and producing equivalent products at all locations requires a good deal of coordination.

Re: TI and future Jaguars
 

I am aware that putting these things in the KOP as a donation is probably out of line for a community project that has yet to 'prove itself'. As I said FIRST communicated that their ability to buy an item is ambiguous. In other words we should assume that if FIRST can't justify making sure that these things are in every team's hands the instant the KOP opens (in short that the new item is vital) to get them in the KOP might requite a donation of around $250,000 in electronic speed controls or even more. That's a lot of money and commitment for a community project, or maybe not, sort of depends on how you look at the benefactors that fund so much of FIRST already. It also depends on how creative the community is with these things (consider the RepRap community as an example).

This being communicated, getting the electronic speed control approved does not require a donation anything near this scale. Personally I think it's quite practical to produce a near production quality prototype to get into the approved components list. This would probably be a dramatically smaller commitment. In that environment you can produce the product in smaller lots and more accurately produce only what you might get money for.

Producing a community oriented electronic speed control is not without precident see the OSMC:
http://www.robotpower.com/products/osmc_info.html

More importantly the beauty of setting our sights on merely getting the hardware approved for use in the manual means that as we develop the product's maturity we neither burden FIRST nor ourselves beyond what would be an otherwise ordinary business venture. If during the course of evaluation (be them for this year or later years) FIRST and ourselves discover the value of the project increases to vital to the FIRST mission statements we could then risk amped up production.

Again I am going to ignore that the Jaguar might be at the end of it's run here. This is about diversity in our approved components. This is not about rushing to fill the void that the Jaguar might leave. It's possible that the Jaguar might fall out of production this year and FIRST will leave it appoved for use (if you can find them to use). It's possible that FIRST can get the Jaguars and this item would be an alternative to the Jaguar. It is safe to say that we can use the FIRST RFQ for the Jaguar as a guideline to frame what FIRST sort of expects in various aspects.

Possibly all of the above, but most particularly separating the high power section from the control aspect, separating the communications aspect from the control processor if viable, and possibly even separating the indicator functions from the control aspect.

For example we could use a cheap module with a PIC at the heart to make a PWM speed control like the Victor when it's connected to the high power H-Bridge section. We could then make larger or smaller H-Bridge sections. We could also make reverse voltage protection modules for the H-Bridge section that could be used during initial setup and removed from the system during competition.

We could create another module with a TI Stellaris that can be connected to the same H-Bridge modules.

We could create another module with a Parallax Propeller that could also use those same H-Bridge modules.

We could create a 'common denominator' interface module for that H-Bridge section that could even enforce FIRST's requirements while allowing teams to produce their own control sections for the electronic speed control. It would encapsulate the current limiting and provide basically a TTL interface to the front end drivers within the 'common denominator' interface module.

We could make it possible to interface LCD modules to the control boards. Think of all the user interface possibilities this would open.

We could make it possible to interface storage modules. We could possibly put memory cards on the speed controls for data logging. We could even put static or dynamic RAM on a module with a possible battery backup (that would be much faster than a flash memory card logger).

The idea here is to encourage diversity without explosive costs. Obviously it's much more expensive to make 20 whole products than 20 parts of a product. Also in-line with the today's FIRST approved choices, if you nuke the high power section you could just replace that part of the modular system.

Re: TI and future Jaguars
 

Also a modular system reduces costs for the teams.

Originally the Victors were more expensive than the beige Jaguars.
The market pressure helped force down the price of the Victors.

However, that's not all there is to the analysis. The original beige Jaguars didn't have the RS232 bridge and that meant you had to get the 2CAN if you wanted to use that (at the time). So one can't ignore that with the beige Jaguars if your goal was to use CAN you had to fork over an extra few hundred dollars for the 2CAN.

In effect the 2CAN was a module of the CAN equipped network of beige Jaguars. You could simply not use CAN and the Jaguars would at the time be cheaper than the Victors (let's ignore other things about performance we know about the Jaguars with this analysis and stick to costs).

I am proposing a similar idea. If you want cheap versions you buy basically the PWM module and the power H-Bridge module. So let's try to keep that near the sub-$100 price range with an H-Bridge that's FIRST level of power handling.

If my team wants reverse voltage protection we fork over the extra cost.
If my team wants CAN we fork over the extra cost.

If my team buys the PWM modules this year with the power sections. Then next year decides to use CAN we can try to revolve a similar enough interface that we build a stock of parts over the course of successive competitions. So we might be able to remove the H-Bridge power sections from the PWM modules we bought the prior year and use them with the CAN modules we bought the next year.

This also saves money if there are unforeseen problems. Perhaps one model of one year's power sections has a problem. Maybe the next year you already have the CAN modules, but you replace the last year power sections with the design flaw with newer less problematic H-Bridge power modules.

In the worst case if the product is generally very well recieved it's possible there could be some economic bootstrapping for only new teams or new users to this product. For example last year only new teams got the newer cRIOs in their KOP. Perhaps there could be a discount for new users of the product to help them build up momentum. This might help drive the market acceptance of the product without risking a large donation of thousands of products into the FIRST KOP.

Re: TI and future Jaguars
 

I'm interested in being a part of this project. I have been thinking about doing it myself for months, but have been waiting until build season winds down before doing anything. For my sanity, I was thinking of targeting getting something working for the 2014 season, so life wouldn't have to be so rushed. But, that doesn't have to be the case since you want to push for next year.

I have already designed a custom motor controller, fabricated boards, and soldered them. This was very low quantity (5), but I have some good experience already from them. Mine are only rated to 5 amps, but the circuitry for an h-bridge is pretty much the same regardless of the amount of power that it will be rated for.

From my point of view, there are a couple of things that jump out at me as necessary features. The controllers need to be able to take anything we ask of them and keep on ticking. Victors currently do this, but the jaguars have trouble with it (First hand experience, multiple times, multiple ways). The switching frequency also needs to be significantly higher (jaguar range) to provide better control. The power circuitry for the uC on the controller also needs to drop out below 4.5 volts, unlike the current Jaguars. That has caused us many problems in the past.

They should also be a lot smaller than the current Jaguars, and the same size or smaller than the victors. I think it would be interesting to try to make them sealed and potentially passively cooled, but that may be dreaming.

I'm not sure that modular is that big a deal, personally. MOSFETS are pretty cheap. $5 per controller at low quantity for nice ones. A CAN transceiver is $1 at low quantity. All you need for CAN is a transceiver, a connector, and a uC that supports it. Most modern microcontrollers now should also be able to support running PID and friends without much worry.

If you decide to go further, please let me know. I know a couple of people who might also help out, at varying skill levels.

Well, off to work. We should meet up at CMP and talk.

Re: TI and future Jaguars
 

I intend to make a real effort to get this done. Several people are in contact with me about this effort now. It's still just starting but I'm committed to giving it some money, a little nurturing and some support from my personal resources. I don't know how far we'll get this year either, but I think we can produce results that are more tangible than just ideas by those deadlines.

We might need to reduce the feature set to make best use of the resources in the available time frame which is another reason I had proposed a modular system. There's nothing stopping us from making both a modular and non-modular system or only one of the other. There are certainly aspects of the non-modular system that could be valuable as well.

I'm going to try to essentially list features and ideas as this goes on. I think it might be wise to possibly enable a sort of voting process for features that lets people weigh in to some extent. That's a bit of a project so I wouldn't expect that immediately. The purpose would be to try to find the most important features we can deliver upon and then fit the resources towards that goal. It might be that people just really want mostly a CAN speed control like we've both been tinkering with and for PWM they prefer Victors.

I'm prepared to contribute to whatever direction the community wants to take it as long as we don't go totally out of the realm of practical.

Re: TI and future Jaguars
 

Wow, TI is bailing out!

So guys/gals, what we have here is an opportunity to create a best-of-breed motor controler for 12V 20-60A range. Are we sure that there is no commercial manufacturer out there that owns this segment?

If not, then this is an opportunity to own this segnment. I liked the Jaguar (with some mods to fix obvious issues). Is TI donating the Jag IP ? If so we could build on from that ...

I think we have plenty of collective "brains" to make a good job of this!

The volume of FIRST is small. But the 12/24V 20-60A segment has got to be huge...

If TI decided to bail out - we should first understand why they choese that path?

Cheers
Dean

Re: TI and future Jaguars
 

One thing that just occurred to me, is that just being FIRST approved would be a huge deal for a community effort that could make the whole need for manufacturers and support companies moot.

About six months ago, I heard a talk by the the principals behind http://diydrones.com. The gist of their operation is that they produce a completely open-sourced design for an autopilot and IMU for making RC planes and multi-copters into complete autonomous drones. Hardware, software, everything is open-source. They setup a small contract manufacturer for making boards in Tijuana, Mexico, but they provide the gerber plot files or other board masks if you want to make your own boards. Likewise, they sell kits that range from a bunch of components up to completely assembled boards. The cost of the finished product is directly related to how much work you want to make for yourself.

Back to the topic at hand, a community designed motor controller could follow the same model, at least if FIRST approves. Under the current rules, this controller would be considered a custom circuit. The open-source nature of the code and hardware schematics would make it available to all interested teams. A prototype reference design, only produced in small quantities would run afoul of the COTS rules, as currently implemented. If FIRST allowed board kits, produced on demand with a completely open design to be equivalent to COTS parts, then there may not be a problem.

-- Len

Re: TI and future Jaguars
 

I don't think so. Custom circuits may not directly control motors.

Re: TI and future Jaguars
 

I need to clarify part of my discussion with FIRST about this matter.

We can make a modular electronic speed control. We can make kits >HOWEVER<:

In order to be approved even for inclusion into the manual, we must have a process detailed that delivers assembled products to teams. That's the reason we must include the nearly production ready prototype (the rules about COTS circuit production are not applicable to this process...approval overrides them entirely).

So we can sell kits if we like, but we must be able to deliver assembled products to teams to meet demand so that the field of available hardware is even amongst the teams.

Not all teams have access to the hardware or skills to assemble an item such as this. We can't even assume that all teams have someone on them that can solder a through-hole PCB. Some of the items in the current KOP do require basic soldering skills but they are not vital to constructing a working robot. Approved electronic speed controls are vital to constructing a robot so we don't get that luxury.

We can make the units modular with connectors. We might even get FIRST to agree to make it so the connectors can be removed and replaced with wires from point to point (think 0.1" headers that aren't soldered in on delivery and can either be soldered in or you can use wire instead like the gyros and accelerometers). However, again, even if we sell kits as a side aspect they'll want the units almost entirely assembled. I don't think they'll accept a list of assembly houses that 'could' do the job either. They'll want as part of our business proposal a clean cut path to us being able to produce and deliver a few thousand units if the demand exists to pay for that. Keep in mind again, if the demand exists to pay for that it would mean that we have a few thousand monetary commitments for the product we wouldn't be donating a few thousand of the product (though at our option we could be discounting some of the costs).

So at very least we would have to commit sufficient assembly houses to being ready to assemble several thousand kits but with the potential of that not actually happening (or the cost). Also we would have to commit the assembly houses to lead times that are practical because if we are only included in the approved list, but not in the KOP, people will only find out and start ordering product the very first day of build season. I would think that any lead time over 2 weeks is asking a lot from FIRST and 3 weeks would be excessive.

One upside of inclusion in the KOP is that the lead times are for delivery between September and Halloween in October. Of course the risk with inclusion in the KOP is the risk we would have to entirely donate enough speed controls to give at least two to every team which is very costly. I should think it makes more sense to target inclusion as approved this year and hope that the product works out so well that FIRST decides that it's vital and then will commit money to help secure it for the KOP a following year. This way if it flops this year we expose ourselves to standard business losses.

Re: TI and future Jaguars
 

Your point is extremely valid. Only approved control devices may control motors (doesn't have to be an electronic speed control, could be a Spike under the right circumstances).

However, I propose that FIRST's primary concern with that rule is safety and to keep the playing field relatively equal.

I think we might be able to create a module with a power H-bridge at it's core that forms an approved 'front-end' for a custom circuit speed control.

Such a module would probably have to have some intelligence to it to implement current limits. To insure that timing of the signals doesn't short the H-bridge. To provide some way for the custom circuit beyond it to measure things like current and voltage at key locations without changing the H-bridge performance. Possibly even a way to indicate that things are overheating. Maybe some place to connect a fan for cooling (or not if you consider the way the fans work on the Victors).

If we did this I suspect we would be required to produce at least one 'interface module' that connects to this 'front-end' (as we don't have the custom circuit to give them) to demonstrate aspects of it's performance and equalize availability to all teams. What sort of interface on the 'interface module' is up to community discussion as well. I would speculate that CAN and PWM are the 2 front runners, but FIRST does have Ethernet, SPI and I2C on the existing control hardware and they would seem acceptable per the Jaguar RFQ we can use as a rough template.

It's not entirely clear to me currently that FIRST would say no to such an idea but I'll inquire further if it's something the community is seriously interested in.

The primary difference between a custom circuit connectable 'front-end' and a modular front end is specifically a question of whether you let people create the custom circuits or dictate functionality to them via the available selection of modules. There's no reason that a module couldn't be made for a modular front end to allow custom circuits and retain the existing selection of modules the community provided to FIRST to be approved along with the modular front end.

If someone made a custom circuit to connect to such a 'front-end' then that circuit would be impacted by the COTS rules. They wouldn't be able to use it the following year unchanged unless the COTS rules change or they provide it to be approved with the community work the following year. Then that newly accepted approved module would be subject to production requirements as well.

Current rules would impact your ability to directly alter the control of the electronic speed controls. So perhaps we could make the custom circuit module available and let FIRST decide during the approval process if they want to open that door. Keep in mind the rules aren't officially set until September. So if this custom circuit module existed and they want to allow that they could alter the rules to allow it.

I can diagram this out if someone wants me to do so. It might be easier to visualize drawn out.

Re: TI and future Jaguars
 

If you're calling the H-bridge the "front end" of the controller, I believe you misunderstand an important part of the approval process. The number one priority for approval is the ability for the control system to shut down all motors regardless of custom circuits or team-written software. The "approved front end" would have to be the part of the speed controller that connects to the rest of the control system. The approval requirements for the part that connects to the motors are going to be much less rigid.

Re: TI and future Jaguars
 

So you make the 'custom circuit module' (which is just one of the available interface modules), that connects between the H-bridge 'front-end' and the custom circuit also have a way to ensure that the control system can disable it regardless of the custom circuit connected to it. All you'd really need is a single digital output with the enable signal from somewhere on the control system and you could daisy-chain that signal from one 'custom circuit module' to the next (these robots are not that large).

Again, I don't envision it as 100% necessary to allow any custom circuits to be added after approval. I do think we can make a module for a modular unit's H-bridge 'front-end' that would allow it and be entirely subject to the approval of FIRST.

It's very appropriate to say that it's entirely up to FIRST if they want to open this door with a custom circuit connected to an approved 'front-end' through a 'custom circuit module'. So we need to be prepared to have it slammed shut if they don't like the idea. That's why we need to ship at least one module that is fixed to perform the interface function to that 'front-end'. That fixed module (PWM, CAN, SPI, I2C, etc) approved with the 'front-end' would be required to adhere to the field shut down while also performing whatever else it does (it wouldn't need the 'custom circuit module' at all so it's more integrated, lighter and smaller.)

Think of the 'custom circuit module' as an adapter between the H-bridge 'front-end' and some team's custom circuit, only it's intelligent and it can override your team's custom circuit entirely. In theory if your custom circuit was utterly perfect and you weren't using this at a FIRST event you'd be able to connect your custom circuit directly to the 'front-end' module and not need the 'custom circuit module' (it exists specifically to allow you to make a custom circuit that could fail and to retain control essential to FIRST during a competition).

Re: TI and future Jaguars
 

One feature I would really like to see in a FIRST approved electronic speed control is the ability to power the control assembly separate from the H-bridge assembly. This way if there's any doubt about the power quality feeding the control assembly you can provide it with a separate power supply to eliminate the possible issues from the motor operations.

This would also be handy if you wanted to log data in the control assembly memory for debugging.

Re: TI and future Jaguars
 

If a modular controller does get approved, I think an add-on module that basically allows you to use any motor as an rc servo would be awesome (rc as in PWM, not CAN).

Re: TI and future Jaguars
 

DC brush also called DC commutator induction motors at least (most every motor we use in FIRST whether or not we call it a CIM). Unlike AC brush or repulsion induction motors, brushless motors also called electronically commutated motors, stepper motors, AC motors, synchronous motors, pony motors (also part of a synchronous motor), pneumatic motors, hydraulic motors, heat engines (phase change, gas, liquid, electron, magnetic) which are different animals (and I'm sticking to things that don't run on ignition).

I think, but I could be wrong, that given the prevalence of PWM and CAN already in the FIRST systems that this project will eventually find itself supporting both one way or another. Might be 2 entirely separate electronic motor controls or the modular solution.

It would also very cool if we could use it to turn the CIM motors into servos to make CNC machines.