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

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Sam.Ramsahoye
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Joined: Mon Apr 27, 2020 1:06 pm
Organization: Arup
Location: United Kingdom

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

Postby Sam.Ramsahoye » Tue May 26, 2020 4:06 pm

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

Nikhar.Abbas
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Joined: Wed Apr 29, 2020 7:11 pm
Organization: National Renewable Energy Lab
Location: Boulder, CO

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

Postby Nikhar.Abbas » Tue May 26, 2020 4:51 pm

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

Sam.Ramsahoye
Posts: 18
Joined: Mon Apr 27, 2020 1:06 pm
Organization: Arup
Location: United Kingdom

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

Postby Sam.Ramsahoye » Wed May 27, 2020 6:18 am

Hi Nikhar,

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

Best,
Sam


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