System identification for helicopter yaw dynamic modelling

This paper presents a method to accurately identify the yaw-dynamic model of an unmanned helicopter. First, the model's structure is established by dynamic analysis. Then the model is reconstructed into a combination of three second-order subsystems. As the distribution of the damp ratios and natural frequencies of a second-order subsystems is limited, the model can be accurately identified from real-flight-test data. Finally, experiments are carried out to identify the yaw dynamic model. Results shown the modeling accuracy is improved through this approach.