Abstract:

The accuracy of helicopter flight dynamics model is essential for helicopter control system design. But the model obtained using traditional modeling method is deficient. In order to meet the demand of helicopter control system design, a method for modeling helicopter flight dynamics is presented. This method combines mechanism modeling method and system identification modeling method. Firstly, an approximate model is developed by using subspace state space system identification method. Combining with the prior knowledge offered by mechanism modeling, many parameters are decided. Then, the remaining parameters are identified by using prediction error method, and an advanced model with constraint of prior knowledge is obtained. In the following flight test, a statespace presented linearized flight dynamics model of a model scale helicopter at hover condition is successfully identified. The result shows that the identified model can predict the response of helicopter accurately, and can be a candidate model for helicopter control system design.

Key words: flight dynamics, system identification, subspace method, helicopter, prediction error method