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ROSCO Toolbox - Relationship Between Integral Gain & Damping of Fore-Aft Mode

Posted: Tue May 26, 2020 4:06 pm
by Sam.Ramsahoye
Hi,

Is there an analytical relationship between the integral gain on the fore-aft damper and the damping of the fore-aft mode in the ROSCO controller? I'm trying to reduce tower-fatigue.

Best wishes,
Sam

Re: ROSCO Toolbox - Relationship Between Integral Gain & Damping of Fore-Aft Mode

Posted: Tue May 26, 2020 4:51 pm
by Nikhar.Abbas
Hi Sam,
Ervin Bossanyi (amongst others) has proposed a simple analytical relationship:
https://onlinelibrary.wiley.com/doi/abs/10.1002/we.95

For the tower fore-aft damping control, the `FA_KI` term is multiplied times a high-pass filtered integrated tower-top fore-aft signal and added to the standard collective pitch command.

Additionally, you could use the "floating feedback" terms to achieve a similar goal. The only difference between the two is the filter for the feedback signals. The tower-top motion signal that `Fl_Kp` is multiplied by is low-pass filtered by the filter defined by `Fl_CornerFreq` and is notch filtered by the filter defined by the notch-filter parameters.

Best,
Nikhar

Re: ROSCO Toolbox - Relationship Between Integral Gain & Damping of Fore-Aft Mode

Posted: Wed May 27, 2020 6:18 am
by Sam.Ramsahoye
Hi Nikhar,

Thanks very much, think I've got it working now.

Best,
Sam