Dear Jason,
Thanks a lot. When I eliminate the generator-azimuth state, it is exactly what I want. However, how to understand MBC_NaturalFrequency and MBC_DampingRatio? How to obtain the information of a rigid-body mode associated with the generator-aximuth state from MBC_NaturalFrequency and MBC_DampingRatio? I know little about this. Can you recommend some document for this? Thank you again!
All the best.
Yanhua