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#1
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Re: PID on Jaguars is Illegal
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#2
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Re: PID on Jaguars is Illegal
is thermal shutdown illegal?
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#3
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Re: PID on Jaguars is Illegal
Here are some other things I'd like to mention.
If the GDC wants to limit what can and can't be done in the Jags, they should have TI write new firmware to disallow any possibility of using these functions. I had a long conversation with the Black Jag designer and firmware programmer from TI last year at the Championship about all the good and bad of the closed-loop firmware that TI provided on the Jags. We were one of the teams that decided to take a risk that the CANJaguar software for the cRIO and Jaguar firmware would mature enough to operate properly for last year. If this was disallowed last year, then there were some serious oversights from the GDC. And now that the code has matured to its greatest form to-date it is illegal. Why would FIRST want TI to improve its closed-loop firmware and also sanction a CANJaguar project if the code is not even going to be used? Also, as someone stated below, distributed computing and control systems is THE FUTURE. How can FIRST claim to be investing in the future if they want to impose archaic designs on teams? We're already using a processor that was introduced almost 20 years ago. Every system around us uses multiple application specific devices. To remove these concepts is shortsighted. Lastly, the Jags basically have a timeout. They're not supposed to keep functioning if a signal is lost - and this timeout I believe is ?100ms. This is well below the threshold for human comprehension. If there is no signal, the Jag shuts down. So to say that the cRIO is not controlling the Jag has be to based on how long one expects the latency to be between the cRIO and the Jag. For example, if the cRIO commands 90 degrees (in position feedback mode) and the motor is currently at 0 degrees, there will be a time delay between when the motor starts moving and when it reaches 90 degrees. The cRIO must keep commanding 90 degrees in order for the Jag to keep trying to make the motor go to 90 degrees. If at any time a signal is lost, the Jag will stop commanding the motor and everything will stop. I also hope this ruling is retracted .One step forward, two steps back. Last edited by Bryscus : 21-01-2011 at 11:03. |
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#4
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Re: PID on Jaguars is Illegal
I don't agree with the statements that the signals are originating from the Jags The CRIO gives a speed/position/current then the Jag following orders. By the same rule <R62> limit switches directly into the jag will also be baned. Thus making the Jag worthless the CAN buss worthless and the whole reason for upgrading the entire control system pointless.
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#5
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Re: PID on Jaguars is Illegal
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If you run the encoders to the digital sidecar and do the PID in Labview then that would be LEGAL. |
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#6
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Re: PID on Jaguars is Illegal
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So encoders etc. plugged into the Jaguars are a necessary condition for one type of distributed speed control, but not a sufficient condition. |
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#7
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Re: PID on Jaguars is Illegal
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This is only for the FRC Firmware in as far as I am aware. There is also a signed mode built into the CAN signal so that any arbitrary device cannot inject motor control signals only "trusted" devices. Quote:
For reference, I strongly hope they change this rule. |
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#8
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Re: PID on Jaguars is Illegal
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The original link is no longer viewable and the answer no longer appears in the Q&A Robot section http://forums.usfirst.org/forumdisplay.php?f=1481 Last edited by MikeE : 21-01-2011 at 16:00. Reason: clarity and sport metaphors |
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#9
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Re: PID on Jaguars is Illegal
Last edited by jhersh : 21-01-2011 at 19:27. |
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#10
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Re: PID on Jaguars is Illegal
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I can't tell you how relieved I am.. |
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#11
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Re: PID on Jaguars is Illegal
c/p from team update #4:
As long as the CAN bus is wired legally so that the heartbeat from the cRIO is maintained, the closed loop control features of the Jaguar motor controller may be used. (That is, commands originating from the cRIO to configure, enable, and specify an operating point for all Jaguar closed loop modes fit the intent of <R49>.) (our software subteam breathes a sigh of relief.) Last edited by klmx30302 : 21-01-2011 at 20:18. |
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#12
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Re: PID on Jaguars is Illegal
I'm glad it's legal. I was looking forward to using it this year.
Of course, after reading this thread earlier today, I spent about an hour abstracting and reworking the code. Although it's still improved, I wish I had known earlier... ![]() |
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#13
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Re: PID on Jaguars is Illegal
It's a relief to see the ruling reversed, but a pity the decision was published in the official Q&A in the first place.
Thanks to the positive contributors to this thread for raising awareness and being a part of encouraging a sensible resolution. |
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