New Talon Speed Controller
 

Andymark just released their new Talon Speed Controller. What do you guys think. One question our team is wondering is will this controller handle lower speeds as good or better than the jaguars?

http://www.andymark.com/Talon-p/am-2195.htm

Re: New Talon Speed Controller
 

I'm super interested to hear what the electrical nerds have to say about this product. Is there any reason to stay with the Victor over the Talon (cost aside)?

Here's hoping we get some of these in the kit of parts.

Re: New Talon Speed Controller
 

I'm excited! If you look at the comments/ratings page on the AndyMark page for Talon, it says that Team 67 demoed them at IRI, they didn't reset like jaguars do, do to high current!

Re: New Talon Speed Controller
 

We'll be receiving a number of Talons and will be testing them alongside our Labview beta testing. It's an extremely exciting product. Active cooling isn't needed. It's got a conformal coating so it's got all the debris protection of the old victors. The higher switching frequency should give a linear response on the order of a Jaguar.

I'm a curious about their PWM input rate though. We know that a standard victor is around 17ms. A Jag is somewhere in the ballpark of 5ms.

What does .9 - 2ms @ 50hz mean? Does that mean it will respond in .9-2ms, but only accepts a change in input at a maximum of 50hz (meaning that the actual best response is 20ms)?

Re: New Talon Speed Controller
 

Personally I'd be a bit more interested to know how these perform compared to a Victor rather than a Jaguar (especially considering how much better reliability Victors have from Jags anyways).

If this turns out to be a controller that would give us the reliability of something like a victor, but with the smoothness of control from something like a jaguar, I'd think it would definitely be the way to go.

Re: New Talon Speed Controller
 

A few notes:
- First, this is not an AndyMark product. It's made by Cross the Road Electronics, and AndyMark is only an outlet for sales.
- It sounds like the new Victor 888 will give this a run for its money, since both have a linear output.
- The passive cooling is a very nice touch
- The conformal coating is something that has been much, much needed in FRC applications. It's nice to see a speed controller that finally has one!

All that said, keep in mind we don't know what will be legal next year. Worst case, we'll still be limited to the Victor 884 and the Jaguar. Best case, those will both still be legal, but they'll add the Victor 888 and the Talon to the list!

Personally, I don't see any benefits the Victor 884/888 has over the Talon. The only benefits I can see from data provided for the Talon over the Victor 888 are the heat sink and conformal coating. Obviously, the linear output is another benefit over the Victor 884. Looking at the documents for each, I believe the Talon also has a slightly smaller footprint than the Victor 884.

Bringing the Jaguar into the mix, we know it has a larger footpint, which is a negative. However, it also has a linear output like the Talon and 888, and provides some additional functionality through the CAN interface and the ability for direct sensor feedback when using CAN.


For me, Jaguars have been preferred up until now (specifically for drive train) due to their linear output. These new controllers though, if FRC legal, completely change the equation. It seems that it now becomes a question of size versus functionality - if you don't need those inputs on the Jaguar, why use one? Depending on the number of speed controllers used and the number of DIO ports used, there might be size/weight tradeoffs available for using Jaguars and CAN, avoiding the need to include a second DIO module and DSC. Definitely something to look at!

Re: New Talon Speed Controller
 

Per the user manual, .9 to 2ms is the pulse width (duration of pulse).

50Hz is the frequency (max? or nominal?) of the pulses that can be processed.

Re: New Talon Speed Controller
 

I am curious if they perform the same as Jaguars at the low speeds, does anyone know? Andy? Mark? Do you know? How about Cross the Road?

Re: New Talon Speed Controller
 

Just for a point of clarification, the Victor 884 featured conformal coating. The new Victor 888 will as well.

Best,
Ricky

Re: New Talon Speed Controller
 

The best part of this is the fact that a rectifier prevents back flow into the controller. Which fried the majority of are jaguars.

Re: New Talon Speed Controller
 

Awesome, I had no idea it did... I looked through the users manual and didn't find any mention of it... where is this sort of information documented?

Re: New Talon Speed Controller
 

It's not clear what your intended meaning is. What rectifier are you referring to? Which controller? And what is "back flow"?

Re: New Talon Speed Controller
 

Do you mean reverse polarity protection?
(See Page 4)

Re: New Talon Speed Controller
 

Ok to clarify my above post.

Are team has found that any sort of free wheel action on the robot (ie pushing it) Causes the motors to become a generator that sends current back into the motor controller. Well with the Jaguars they didn't have anything to stop it so we fried a lot of them. The new Talon controller has

Re: New Talon Speed Controller
 

We have been pushing around robots with Jags as long as they have been available and have never experienced this problem.

Re: New Talon Speed Controller
 

Interesting but in how long of increments like a few feet we have found that they would be fine. but a rookie pushing the robot down a hallway instead of using a cart was a problem. Also it could depend on if the robot is on or not.

Re: New Talon Speed Controller
 

Like IndySam, we've been doing this for years with no adverse affects on the Jaguars. This includes pushing it from one room to another (probably 100 ft). This is almost always with the robot off - we never push it long distances with it on... although just last night there was some small pushing going on to manually line the robot up for some testing while it was on (a few feet at a time).

Re: New Talon Speed Controller
 

This lead me to think that it is when the robot is on it leads to adverse affects if pushed more then a few feet. I have noticed that when on the robot is harder to push but that could just be me.

Re: New Talon Speed Controller
 

It is currently documented only on the Product Web page. We'll make sure the manual for the Victor 888 includes this information.

Thanks,
Ricky

Re: New Talon Speed Controller
 

From the scant technical detail so far available (if there's a schematic I haven't seen it), I can't see any reason why the Talon should be any different from the Jag when not powered, or when powered with a zero throttle command (in the deadband zone, you're either coasting or braking, not regenerating - someone please correct me if this in incorrect).

Re: New Talon Speed Controller
 

Ether: So do you see anywhere where it gives us the actual response of the Talon? 5 ms like the Jag, or 17 like the Victor?

I'm curious because I know some teams switched to Jags for better shooter control this year specifically because of the 5 ms response over the 17.

Re: New Talon Speed Controller
 

Sorry Tom I haven't seen that anywhere. I assume Mike will provide that info the next time he visits this thread.

I'm guessing that the 50Hz number (20ms period) was given because it corresponds to the 20ms TeleOp period? The Talon may be capable of processing pulses coming in faster than that. But there's the driver issue. As I understand it, if you send commands at 10ms (100Hz) to the Victor driver, for example, you still get a 17ms period coming out of the driver.

Re: New Talon Speed Controller
 

From the Talon User Manual "A Talon is a device used to control the rotational velocity (speed) of a brushed DC motor through modulating power over time. The Talon accomplishes this through an efficient form of rectification known as locked-antiphase rectification. This type of rectification returns current to the power source during the freewheeling period of the motor and during direction change."

From this quote and from what I perceived form talking to a guy from crosstheroadelectronics at IRI, I believe the Talon does have some regenerative capabilities. How they work and when they are active are two things I would love to have some clarification on.

Re: New Talon Speed Controller
 

Well this is fairly exciting. I must confess that I would like to do a three way comparison of Victor vs Jaguar vs Talon. Last season we had issues with our gun for a while and were able to track that in part to what seemed to be the non-linear-ness of a Jaguar. We ended up swapping it for a Victor, which greatly improved the situation. Based on the supplied charts from the User Manual, the Talon seems to have pretty good linearity. That would certainly be an interesting series of tests for Beta Testing. (I am also wondering if the David Relay will be coming back for more testing, it was a neat little box of fun)

Although a rather minor point, I really like the lights feature, "The rate at which the led blinks is proportional to the percent throttle. The faster the LED blinks the closer the output is to 100% in either polarity." From the Jags and Victors I am very reliant on the color change for basic testing and while the blinking will probably serve more as a qualitative measure, it seems like a neat feature to have. (Although I'm sure that if I work with the Talon, a month later I'll have stared at blinking lights enough to go a little crazy).

I am a little surprised that there seems to be no CAN support, especially since this comes from Cross the Road Electronics, a vendor that supplies not only a lot of CAN equipment but 2CAN as well. There would have to be a major change in hardware to accommodate it, so I guess we should not be expecting CAN + Talon any time soon.

Looking ahead for the season my two logistics questions would be: what will come in the Kit (Rookie and Veteran)? If AndyMark is not selling Jaguars, who will?

Re: New Talon Speed Controller
 

Lack of CAN means we still have to use Jaguars :/

Re: New Talon Speed Controller
 

Why is PWM out of the question?

Re: New Talon Speed Controller
 

We have killed at least one Jag this way (I think two), as well as another my hooking the output to power (which is almost the same thing) (all the Jags were tan). The one (or two) we killed, died when the robot was pushed fairly quickly. Since then, we try to avoid pushing the robot or at least push it slowly. We've never killed a Victor this way and have pushed these robots around much more aggressively.

Re: New Talon Speed Controller
 

The .9 to 2.0 ms with a 0 output at 1.5 ms asymmetric response confuses me. Why did they do this? This is going to lead teams to terrible out of the box experience. If the Talon is hooked up to the controller and the present Victor motor drive routines are used, then a team will not get full power in 1 direction. This will require calibration. One more step for teams to screw up. Which will lead to rants and support issues. The pulse timing is listed as 10 bit or 1024 buckets. With calibration there will be less settings in one direction than the other. Does it matter? probably no. The question this year will be " Did you calibrate your Talon." Response - "I don't know." "You have to calibrate your Talon." "How do you do that?" and on and on. Cross the roads - It's time for a firmware up grade before you let this thing out in the wild. Your life will be better if you correct this now before the Chief Delphi Flamming starts. Why was this done? Is it a clock counter timer issue? Asymmetric I don't like it. I don't remember ever seeing a commercial speed control with asymmetric response.

Re: New Talon Speed Controller
 

This was a typo in the User Manual. The actual refresh rate is 333Hz or (3 ms). The input capture is driven by an interrupt so as long as there is some space between the edges of the input pulse, the output will update correctly.
If your pulse spacing is 3 ms or greater you should have no problem.

Re: New Talon Speed Controller
 

Ok,

Sit down, relax...I assure you the sky is not falling.

There were a couple typos in the user manual, the ACTUAL expected pulse width is 1.0-2.0 ms with the center = 1.5 ms. The user manual should have read .990-2.010ms. The reason for the 10 us gap is to over drive the pulse to ensure that any error in the input pulse does not cause the output to transition between full on and chopped. Let me make something perfectly clear; This is not necessary for the Talon to function smoothly or symmetrically, just a recommendation. On top of that the Talons firmware has 10 us(2%) of padding on each extreme of the input pulse.

Screwing up calibration is not really possible. The calibration values are checked against bounding values. If the cal values are outside of those boundaries the Talon will simply use the last "good" calibration values. The worst that could happen is truncation of the output.(full throttle is obtained at a lesser input value) But even then all you are really changing is granularity or resolution. Remember the Talon is 10 bit, the Victor uses 8 bit(which BTW is more than enough resolution)

Also to assume that you would only have two speed controller classes as before would be presumptuous. The Victor and Jaguar classes both use different timing parameters for full forward, full reverse and center. The Victor class uses 2.035ms = MAX, CEN = 1.526ms, MIN 1.032ms, this is also asymmetrical. If the Talon is deemed legal a Talon Class would most likely exist.

As far as calibration is concerned, if you are not already calibrating your PMW based motor controllers, you should be. Calibration not only corrects for pulse timing discrepancies, it also scales the out put MIN, MAX, and CEN to your joystick MIN, MAX and CEN.

So you can relax there is no need to upgrade your firmware, or flame the thread(although from my experience this will happen anyway). It was simply a mistake in the user manual.

Re: New Talon Speed Controller
 

Calibration of motor controllers is a pretty standard practice in RC (especially in the quad rotor world). If the controllers aren't calibrated, the motors will not be in sync (i.e. receive the same power input) -- which could be an issue for motors that are mechanically linked. In quadrotors, the motors are linked via software PID for stability purposes, meaning uncalibrated motor controllers will cause a quadrotor to crash almost immediately.

Re: New Talon Speed Controller
 

Any hint from FIRST as to when we might know if the Talon is legal? Before Jan 5th?

Re: New Talon Speed Controller
 

Mike,
We switched to use CAN bus last year and was starting to enjoy using it. Plus we have invested in a couple of 2CANs. Any idea if Talon will eventually support CAN?

Re: New Talon Speed Controller
 

I suggest the first hint will probably come to the Beta Test teams, but there probably won't be any guarantee until kickoff!

Re: New Talon Speed Controller
 

The answer is yes. And thank you.

Re: New Talon Speed Controller
 

Greetings, a new season has begun! and we seem to have a new speed controller that looks like a Vic!

A quick look at the Jag schematic says that when the robot is pushed, the generated current will try to flow in such a way to charge the battery. But if the battery is not connected the voltage to the PDB will keep rizing... Is there something in the PDB that will shunt this current - or something will blow!

Dean

Re: New Talon Speed Controller
 

Camren,
The type of locked antiphase PWM modulation that is used in the Talon is simply the method that used to turn on the FETs that provide motor currents. The FETs in the Talon, Victor and Jaguar all have diodes that provide a path back to the power supply while the motors are coasting or being pushed. This diode is a result of manufacture as I understand.

Rickie and Jon, not to mislead, the conformal coatings on the Victors protect the circuit board components, but the leads of the FETs are still sometimes exposed. Metal swarf still can kill a Victor but they are far more immune to this than the current TI/Luminary production Jaguars. I am going to guess (highly recommend) that the IFI production runs will contain the same conformal coatings as current Victor products. The really difficult component in the Jag to coat is the current sense resistor since this can dissipate large amounts of power/heat. However, if metal falls across it, there isn't likely to be any catastrophic failure since the value is so small.

Re: New Talon Speed Controller
 

Al,

Yes, the Jaguar will feature the same conformal coating as the Victor.

Best,
Ricky

Re: New Talon Speed Controller
 

Sorry I've been out of the loop on this all summer:
What was the outcome of FIRST's RFP for Jaguar replacement?

Thanks,
Dean

Re: New Talon Speed Controller
 

Re: New Talon Speed Controller
 

Dean,

Going forward, IFI will be manufacturing, selling, supporting, and donating Jaguars to the 2013 Kits of Parts.

More details are here: http://www.usfirst.org/roboticsprogr.../blog-10-03-12

Ricky

Re: New Talon Speed Controller
 

Thanks and excellent news!

I noticed he following:
"Second, the firmware will be modified to remove the current limit protection "

That is great too as that was probably the most significant issue with the Jag (there are others elaborated on on the blogs). However, I hope the current limit is only increased rather than dissabled completely (as in by shorting R23).

Thanks,
Dean

Re: New Talon Speed Controller
 

All of our testing over the last 2 weeks has been at a refresh rate of 242Hz, as I was too lazy to reconfigure the PIC we're using for pulse generation.

I hope the Talon gets FRC approval. So far, this thing is bulletproof.

Re: New Talon Speed Controller
 

So far, we've seen a whole lot of reasons to choose the Talon over the older Victors. The biggest one for us is that the talon is showing linearity as good as the Jag, better control around the zero point (smaller dead band), and a victor-sized footprint.

For an idea of just how bad the linearity is on a the Victor, look here:
http://www.fightingpi.org/Resources/...12_Day_3.shtml

Many teams have fixed that in software - so it can be done, but it's an extra step that is better handled in hardare.

Of course, there's a new Victor coming out as well. It's not exactly fair to compare an old product to the new Talon. Apples to apples will be the new Victor vs. the Talon.

Re: New Talon Speed Controller
 

Wow. That non-linearity is pretty ugly.

Re: New Talon Speed Controller
 

Darn, I was planning on doing a test like this later this fall (I was waiting for the new Victor)! When the new Victor comes out, can you add results from its performance and let us know here? I'd be very interested to see how it compares.

The Talon definitely looks good!

Re: New Talon Speed Controller
 

You really need to have some form of inductive load on an h-bridge to measure its linearity. The current gen Victors are very non-linear, but your measurement technique significantly over-states this.

Essentially, for a given bridge frequency and rectification style there is inductance * average current combination above which the bridge is nicely linear. Below that threshold, you will see weird non-linearities that are highly dependent on the specific motor and amount of current flowing. Above that threshold, it is close enough to "perfectly" linear.

Re: New Talon Speed Controller
 

Guys:

Read the fine print. That's open-circuit voltage linearity.

When connected to a loaded motor, the Vic 884 is much more linear.

Re: New Talon Speed Controller
 

Yup, that's why I said a test like it, not the exact same test :p I've actually been talking with one of our mechanical mentors for the past 10 minutes about how we could best do a simulated load to repeat this testing with our team... We were thinking of putting two CIMs into a gearbox, and setting one of them to Brake (sending it a 0 signal), while trying to drive the other one. Any better ideas out there?

Re: New Talon Speed Controller
 

If you can get your hands on a big programmable DC load, connect the second CIM to that and you can then vary the load on the drive motor across a wide range. Finishing building mine has been on the "list of stuff that never gets done" for a while now.

You also can just put big various power resistors on the second CIM. We used to call them "toasters" in the motor lab.

Re: New Talon Speed Controller
 

For anyone thinking about doing similar testing this offseason, I would recommend using the PWM class rather then the Jaguar/Victor Class. This removes any bias from scaling built into the Jaguar/Victor Classes.

Re: New Talon Speed Controller
 

Or use this.

Re: New Talon Speed Controller
 

Joe - This is a rather interesting point. Using the PWM class would allow you to more accurately evaluate the speed controllers in a "stand-alone" fashion. However, that doesn't represent real-world (maybe FIRST-world is a better term?) use. When we use the speed controllers, we use the appropriate class to control them, specifically to allow the built in libraries to aid in scaling to give us a better response.

My thought is that teams would rather see results as though it was on their competition robot. However, it could be a great learning opportunity to run it both ways - then we could view concrete data on what the built in libraries actually do for us, and show the students the actual reason for doing things the way we do them.

Re: New Talon Speed Controller
 

I would agree, if there was a Talon or Victor 888 class.

Re: New Talon Speed Controller
 

Someone mentioned apples-to-apples in an earlier post.

An argument could be made that for purposes of comparing the various motor controllers to each other, you want to run them without intervening third-party software.

Re: New Talon Speed Controller
 

Thanks for the suggestions guys. We'll go back and retest the linearity under a constant-load scenario. We'll trying using the PWM as well, to see if anything is significantly different.

Also, it appears we've had an offer to start testing the Victor 888's. I'm fairly excited to get side-by-side comparisons for both new products. More variety is always a good thing.

Re: New Talon Speed Controller
 

Tom,

The beta test URL link in your sig appears to be broken. Or maybe it's just my DNS acting up again?

[EDIT] it works now, but the LabVIEW tutorial link doesn't [/EDIT]

Re: New Talon Speed Controller
 

Nope, it was my link. We just finished converting the whole site over to using Server-Side-Includes, and I didn't update the page extension to .shtml.

All fixed. And All Fixed again. Silly website revisions.

On another note, we're horribly behind right now. Our Labview 2012/13 installtion backfired on us. We were running administrator accounts, but we didn't right click the setup file and 'run as administrator'. There appears to be a world of difference when it comes to Labview between those two instances, so we're redoing 5 hours of Labview Installations.

Bleah.

Re: New Talon Speed Controller
 

That's so the rest of us don't have to.
Thanks for the effort and the warning:)

Re: New Talon Speed Controller
 

From my experience, this isn't just a Labview problem... this is a Windows 7 problem (I assume that's what you're using?). They've started switching us over at work, and a lot of guys I work with have had all sorts of trouble getting software to work correctly due to permission issues.

Still, it's good to find it now, so it can be called out in the instructions in January!

Re: New Talon Speed Controller
 

Updated: added linearity tests with load and the Victor looks much better. The Victor 888's should be here Thursday or Friday, so we hope to get results for them out this weekend.

Re: New Talon Speed Controller
 

How did you measure voltage? Output of speed controllers is pulsed:

http://www.chiefdelphi.com/forums/sh...64&postcount=9

Any chance of measuring loaded rpm for the speed controllers?

Re: New Talon Speed Controller
 

That's a good question for the unloaded measurements that were initially made. However, once you hook the speed controllers up to a motor, the motor essentially averages out the pulses for you. Last year we went to show the team how the speed controllers work by hooking up the output to our oscilloscope. At the time, the motors were still connected, which caused no end of confusion for me... I was expecting to see a waveform, and got a solid line at what looked like the average voltage you would expect! After the big "aha!" moment (more of a forehead slap and calling myself an idiot a few times), we unplugged the motors and saw the expected pulsed waveform.

Re: New Talon Speed Controller
 

Many DC voltmeters can read the RMS of a pulsed waveform.


Measuring loaded RPM is in their test plan. (The test plan is linked in Tom's signature)

Read Tom's most recent post in this thread. They re-ran it loaded and measured motor voltage. Motor voltage data should be similar to motor speed data, but I agree it would still be useful to compare the two.

Re: New Talon Speed Controller
 

Tom,
Just to be sure, your load in these tests is the window motor?

Re: New Talon Speed Controller
 

The way I read it Al, the window motor was the powered motor, and the load was the friction of the belt trying to drive an immobilized device:

I believe the output would have been even more linear had they used a different motor with a heavier load.

Re: New Talon Speed Controller
 

That is correct. The window motor is connected via a vacuum drive belt to a 3/8 inch steel roller. We locked the steel roller in place so that the vacuum belt was slipping. That provided a constant load on the window motor.

Re: New Talon Speed Controller
 

Tom,

For each motor controller, how long did it take to run the test and record the data?

Also, did you record the motor current (a measure of torque load) ?

Re: New Talon Speed Controller
 

Tom and Ether,
I was just trying to equalize our previous discussions with regard to motor inductance and controller type. The window motor having different inductance than that of the CIM or larger Banebot types.

Re: New Talon Speed Controller
 

I'd like to see motor inductance and rotor inertia specs for all the FRC motors. I can dream, can't I? :-)

Re: New Talon Speed Controller
 

Perhaps we can convince Rich to make that in his spare time.

Re: New Talon Speed Controller
 

Al, would using a motor with a larger inductance considerably change our results? We didn't have a ready-made clutch mechanism that would provide constant torque back to a CIM, which is why we went with the window motor setup (it was how our ball-magnet worked in 2010).

Ether - the tests were performed quickly, within a span of about 5 minutes - one person ramping the PWM value in labview, another measuring, and a third inputting into excel. We measured the battery voltage before and after and did not see significant change.

Re: New Talon Speed Controller
 

If you ran a CIM at 25% of stall torque I think you'd see a noticeably more linear curve.

I asked about the current not because of concern about battery voltage, but because current is an indication of motor load -- which affects linearity.

Re: New Talon Speed Controller
 

Yes, significantly. The non-linearity is from when the current ripple exceeds the average current. Doubling the inductance cuts the ripple in half, which in turn cuts the critical average current number by half as well.

Re: New Talon Speed Controller
 

I see. We may go back later and look at linearity when hooked to a cim. I think we want to move on and hit our other tests, then circle back around. One last question. Would holding the cim shaft completely stationary then applying different motor voltages result essentially the 'best case' for linearity from the victor? I supposed that's something we could do fairly easily. We'd just have to do it for very short periods of time to prevent breaker-popping.

Re: New Talon Speed Controller
 

Tom,
I don't remember seeing inductance numbers on most of the motors. Just having a larger motor doesn't mean the inductance is higher. It is more a function of the number of turns of wire in the motor. In the case of the CIM motors, as in most motors, the brush assy actually contacts more than one of the many windings. In the case of the window motor, (trying to remember from several years ago), there are three windings and a three segment commutator. So while running, one of the windings is always shorted out by the brushes. My gut tells me that the window motor has a higher inductance.
Holding the motor shaft on the CIM should not affect linearity but will cause max current all the time. This would be bad for both the motor and the speed controller.
As an explanation, inductance tends to oppose a change in current. So there is a definite length of time for the current to reach maximum when voltage is applied. When the pulse length is short, the current does not have a chance to reach maximum. The designers of the Victor took that into account when they reduced the switching frequency to 150 Hz. The Jag designers on the other hand were looking for fine motor control/linearity and that was accomplished by increasing the switching frequency to 15 kHz. For most of the motor we use, the low throttle values are significantly shorted than the time needed to reach full current. As memory serves, Ether did a simulation a few years back to demonstrate this.

Re: New Talon Speed Controller
 

For what it's worth, we usually linearize our motor controllers based on output velocity and not voltage. This seems to work well.

Re: New Talon Speed Controller
 

Tom, can you elaborate more?

Do you use the encoders in your drivetrain to measure the rate at different PWM outputs, create a polynomial from the resulting values, then use function in between the user input and motor set command?

Do you do it free in the air, or under some type of load?

Re: New Talon Speed Controller
 

Tom,
We use the rotary encoders attached to a shaft in the transmission usually. This helps with autonomous as well.

Re: New Talon Speed Controller
 

Couple comments. The window motor problem seams to only be experienced with positional control under PID. There are 2 parts The locking pins locking and the unit becomes locked up. The other is the heating of the PTC. The window motor test should not experience these problems. We only had problems with the window motor in 2010 while using them for our swerve steering.
Over the years many teams have used a joystick to victor function to change the response. Many times when the drivers get involved the function does not linearize the response. It is set for a " feel" that the drivers like. We have done this with jags too. We Got our Talon last week and will install it tonight for this weekends' competition. Will probably put it on the shooter motor.

Re: New Talon Speed Controller
 

We did it in the air using the encoders. Basically, we wrote an autonomous routine that sets the output PWM from 0 to 1 in steps of 0.01, pausing for a second on each value to achieve steady-state and recording only the last speed measurement.

We then normalized the speeds to [0,1] and plotted the results in Excel (PWM on the Y-axis, measured speed on the X). Playing around with Excel's trendline tool gave us the polynomial that looked the best, and we just took the coefficients and plugged them right back into our code.

Afterwards, we ran through the entire exercise again with the linearization function in place to verify that PWM was now linear with speed.

Re: New Talon Speed Controller
 

Doesn't linearity depend on the load? Running the wheels in the air doesn't give you a realistic scenario. This is a long thread and I did not follow it very closely so I may be missing the point but if the goal is to make joystick drive of the robot more smoothly and more linear with respect to the joystick movement, shouldn't PID control on speed automatically do that? (i.e. the joystick reading specifies the "speed" instead of "power" of the robot).

Re: New Talon Speed Controller
 

To some extent, sure, but the frictional load of the gearboxes and wheels was close enough for our purposes, plus we were too lazy to figure out a way to apply a constant load while keeping the robot stationary. If we needed perfect linearity with the joysticks we would have implemented closed-loop control (as we did with the shooter after first linearizing with this method).

Re: New Talon Speed Controller
 

Neat. Add a file-write to your auton routine, then a file-read on your actual linearization routine and you could do this in a minute or two in the pits and have it load the coefficients automatically when your robot boots up. Labview has a built in polynomial fitting VI that could be used to generate the coefficients.

Did you also attempt to correct for inequalities between the left and right sides of your drivetrain when you did this?

Thanks! I think we'll give that try for Beta.

Re: New Talon Speed Controller
 

This might be of interest:

http://www.chiefdelphi.com/forums/sh...3&postcount=10

Re: New Talon Speed Controller
 

We didn't try; I don't recall that we noticed any significant difference between the sides or the directions of motor rotation, but that would have been a good place to fix it. We just took one set of data and used it for all four side/direction combinations (Tom and I are lazy and like to stop at "good enough", unlike some of the other mentors :)).

Something else I forgot to mention before -- we also tweaked the constant term in the polynomial such that the output is saturated slightly before the input reaches 1, to guarantee that the Victors receive a full-power signal at the extents of the joystick travel even if there's something slightly off mechanically or if there's rounding/precision error in the code.

Did u guys hear that the same people now are making jaguars and victors

Re: New Talon Speed Controller
 

Yes and you would have known that if you had read this thread :)

Re: New Talon Speed Controller
 

Talon, Victor888, Victor884, and Black Jaguar speed vs torque tests at various PWM command levels.

Re: New Talon Speed Controller
 

Nice job on the testing and presenting the data!

Based on these results, the Talon is looking pretty good. Nice linearity, both speed vs. torque for constant demand, and speed vs. demand for constant torque. Like a Jag. Should produce a nice intuitive feel for drivers.

Re: New Talon Speed Controller
 

It seems like the Talon is essentially just a different version of the same thing that the new 888 and Jaguar provide. There's really no appreciable difference between them, except that the Talon provides passive cooling. As a side note, based on the dynamometer tests, it seems like the new models (not the 884) have a much better high-side driver for full power and lower resistance than the older 884.

Re: New Talon Speed Controller
 

There are some other differences:

- Smaller footprint
- Lower mass
- Improved ingress protection
- Secure PWM connection
- Brake is maintained during disable
- PWM input can be split (2 Talons on one PWM channel)
- Higher switching frequency
- Lower on-state resistance
- Locked anti-phase rectification
- Clear polarity indicators
- Smart LED

Re: New Talon Speed Controller
 

What test data are you looking at as a basis for that conclusion?

Re: New Talon Speed Controller
 

Mike, can you please tell us what is the rated maximum forward current the LED in the Talon's optocoupler can sustain without damage? Also, what is the minimum current required to guarantee pulse detection? One more: what is the rated maximum reverse voltage it can sustain? I ask because I want to make sure I use a properly designed cable with the custom PWM signal generator I use for testing.

Re: New Talon Speed Controller
 

The Talon looks great, but it is going to have to compete on price with the 888 to make it on to our robot for 2013. We will probably wait until January to purchase speed controllers.

Re: New Talon Speed Controller
 

Maybe I missed something, which is highly possible, but from what I've read, the 888 is approved for 2013, but I haven't seen the same for the Talon.
I HOPE I'M WRONG!!

Re: New Talon Speed Controller
 

Yes, you are wrong... There has been NO official communication that the Victor 888 is legal this year. Personally, I believe we'll be told which speed controllers are legal prior to FIRST Choice going live, as that could directly influence how we spend our PDV's.

Re: New Talon Speed Controller
 

This is one time when I don't mind being wrong.

The reason I believed, and still do, that the 888 will be legal is based on the announcement of the price they will be available for during Dec. 5th -April 20th.
I know I'm reading the tea leaves here, but this reading seems fairly clear, IMHO.
Now, if the Talons go for a similar price, the decision might be a bit more difficult, but for now, the 888's seem to be an "obvious" choice......once officially approved.

Re: New Talon Speed Controller
 

While I think it is certainly great that IFI is putting the new 888 controller on sale at $50 I find the timing interesting... pretty much pushing the Talon speed controller sales right down the toilet.

i have some and I think they are really nice in form factor and performance but how can a team reasonably want to use them if they are twice as much as the new 888?

Re: New Talon Speed Controller
 

From the FRCBlog post, the only motor controllers that can be bought with the PDVs are the Jaguar or Victor (not sure which one) from IFI. The AndyMark PDV excludes items that AndyMark carries from other suppliers (Talon - Cross The Road Electronics).

Because of this, it is a real possibility that FIRST won't officially tell us if the Talon or Victor 888 (if the 884 is the only one offered with the IFI voucher) will be legal till kickoff. I would really like FIRST to come out and clear up some of this confusion though as soon as possible. If IFI is selling the Victor 888 on December 5th at $50 for FIRST Teams then I think we are all going to assume that they are legal. I don't think it is fair for the Talon by Cross the Road Electronics if we don't know it's legality by then. I would doubt many teams will plan on using the Talon when they already assume the $50 Victor 888 will be legal.

The Talon does offer some advantages over the Victor 888. It does have a lower R_DSN or "on resistance" then the Victor 888 and this would equate to power savings and allow more power delivered to the motor when near stall or highly loaded. Ether's tests support this showing the spike current to be near 130 amps for the Talon and only 120 amps for the Victor 888. It also has a few handy features already mentioned. Whether these differences will be worth and extra $50 per controller and the wait to know if they are legal is going to be decision teams will have to evaluate for themselves.