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Offer of help with tuning PID loops

Posted by George Tarrant on July 20, 2011 at 11:35pm

Sorry, but I should have made clear that my autopilot design experience relates to fixed wing aircraft so I won't be able to help with rotary airframes.

I should also emphasise that the databse I have relates to PID control only. After a lot of hard work, I have established which stability derivatives the PID gains depend on so that the job for the user becomes one of estimating certain stability derivatives (for which formulae are also available). The PID gains then drop out as functions of speed. Robustness is assessed by perturbing the values of the stability derivatives.

Finally, could I caution people using textbook PID tuning merthods to do so with care. They concentrate on obtaining a good response to the desired input. In a flight control context, it is just as important to be able to reject unwanted disturbances and this modifies tuning objectives.

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Comments

  • Developer
    Michael Smith July 22, 2011 at 12:28pm

    George,

     

    This is a remarkable offer and I'm truly a little surprised that more folks haven't jumped on it already.

     

    Something that would help, I think, would be if you could clarify what inputs one would need to supply you with for the process, e.g. airframe data, sensors, etc. in order to make it easy for someone that wanted to take you up on your offer.

     

    It would also be interesting to hear your thoughts on applying your techniques in an automated fashion.  One of the biggest hurdles for someone starting out in this hobby is keeping their investment in one piece long enough to complete the basic tuning.  If some of the broader strokes of your tuning could be integrated into an autopilot such that without (much) a priori knowledge of the airframe it could self-tune to a survivable state the barriers to entry would be lowered considerably.

     

  • Rebel K July 22, 2011 at 8:24am
    Any idea about the PID tuning for the Dynam Hawk Sky platform?

    Thanks.
  • John Hestness July 21, 2011 at 2:52pm

    George,  Hi, thank you for your kind offer.  I am tuning this http://secure.hobbyzone.com/PKZ4475.html T-28 model, with the extra equipment it weighs 39 ounces AUW, 44 inch wing span etc.  I have tuned gas process equipment at work but I defer to you for this.  What would you suggest for PID? 

     

     Also I am considering a skywalker http://www.lowpricerc.com/product_info.php?products_id=981 and I think a lot of other people are, any reccomendations for that?

     

    Thank you for offering your expertise.  John

  • frederic reblewski July 21, 2011 at 2:47pm

    it would be great to have a technical/practical paper describing the method

     

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