Hope you are doing well. i am working now on structural control (TMD in FOWT).
I knew that Professor Lackner and Professor Rotea created FAST SC which is a sub module of ServoDyn.
It contains two options of energy dissipation devices: TLCD & TMD.
I found a pdf on NREL site which you revised, containing the equations of motion of the TMD in the nacelle(’ https://www.nrel.gov/wind/nwtc/assets/pdfs/tmd-theory.pdf '). After reading this pdf, i realized that it is based on Newton’s second law and it was easy for me to understand what is going on and not on kane dynamics. Even, when reading OpenFAST source code, StrucCtrl.f90, the equation of motion are written using Newton’s second law.
However, i am looking for a file FAST SC where the equations of motion of the TMD are written in kane dynamics. Does this file exist ? if yes, could you please tell me where to find it or share it with the community ?