Dear Jason,
You are right. I changed the azimuth angle this time. I approximated the azimuth angle as the integral of rotor speed. But the problem still remained. I can’t figure out what the reason is. Actually I found my problem is same with the case 2 “- 2 Deg Pitch Increment in Open Loop Condition.” in previous post in [url]Fast Linearized Models]. He said that the possible reason may be “the offset error in the DOF_GeAz derivative causes non stationary terms in some output variables.” But I can not understand it. Can you help me to fix this problem?
Thank you so so much.
All the best.
Yanhua