Active structural control in OpenFAST

Wind & Water Computer-Aided Engineering Software Tools
1

Hello everyone,

I am interested in applying structural control in FOWT. Indeed, a tuned mass damper will be attached to the structure and will be given a force in order to enhance its vibration mitigation capability.

In order to achieve this in OpenFAST, there are two ways (I am using windows OS):

1- Modification of the source code in StrucCtrl.f90

2- Use of the EX_Bladed_Interface.

As a first test, i modified the source code (option 1), then i recompile OpenFAST using Visual Studio 2019. To compile, I choose Release and x64 (my computer is x64 bit processor) and click on Build —> Rebuild Solution (see figure).

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Compiling OpenFAST was successful ! No errors in the code and i run a simulation with the compiled openfast and i have seen the effect of the modification i have done, on the response. However, this method of working is not practical.

My question is how to compile a dll of type bladed in visual studio. Steps ? manual ?

Does anyone has worked on this before ?

Thank you in advance.

Best Regards,

Riad

2

Dear @Riad.Elhamoud,

A Visual Studio project file for compiling the Bladed-style DISCON controller is available in the OpenFAST repository–see: openfast/vs-build/Discon at main · OpenFAST/openfast · GitHub.

Best regards,

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3

Dear @Jason.Jonkman,

Thank you for guiding me. I successfully compiled the Discon.sln and obtained the well-known Discon.dll.

However, i have some questions for you.

1- I was looking at ServoDyn input file of the 5 MW barge-type FOWT in the section named Bladed Interface.

In line 78, it is written:
“DISCON.IN” DLL_InFile - Name of input file sent to the DLL (-) [used only with Bladed Interface]

However, i did not succeed to find this DISCON.IN.
Am i wrong ? Should i find it in the same folder of ServoDyn input file ?

2- I used the .IN file obtained from this example: ROSCO/Examples/23_structural_control.py at main · NREL/ROSCO · GitHub

I use it instead of the original DISCON.IN in ServoDyn of the 5 MW barge-type. Unfortunately, nothing happen. Is it normal ? I understand from reading the python in the 4th example in ROSCO repository: ROSCO/Examples/04_simple_sim.py at main · NREL/ROSCO · GitHub
that this example could generate .IN file from .yaml file. Is my understanding correct ? Can i use it to generate my own DISCON.IN and put it in the barge ServoDyn.

3- Could you please explain to me the relation between ROSCO and Discon.f90 ?

Thank you a lot.

Best Regards,

Riad

4

Dear @Riad.Elhamoud,

The Bladed-style DISCON interface is a generic interface for coupling controllers with OpenFAST (and other aeroelastic codes such as Bladed). The original NREL 5-MW baseline turbine models used a simple baseline controller implemented in DISCON format. Since then, ROSCO has been developed as a much better baseline controller, which is also implemented in DISCON format. But the sample NREL 5-MW baseline turbine models still rely on the original baseline controller, not ROSCO. The original baseline controller does not make use of a DISCON.IN input file (rather, the controller parameters are hard-coded within the DISCON source code, requiring a recompile of the DLL to change. The ROSCO controller makes use of controller parameters set within a DISCON.IN input file.

I hope that helps.

Best regards,

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