小型共轴式直升机纵横向动力学建模与辨识

Flight dynamics model and system identification of longitudinal and lateral channels for a small-scale coaxial helicopter

运用经典的叶素法和一阶谐波理论,建立了悬停状态下某小型共轴式直升机纵横向通道的理论计算模型;同时根据飞行试验中采集的直升机输入输出数据,以参数化理论模型为基础,运用系统辨识的方法得到了该机纵横向通道模型.通过计算机仿真,分别对理论计算模型和系统辨识模型进行了时域验证和分析,并比较了2种模型的稳定性导数、操纵导数及特征根,对该直升机的稳定性进行了分析.研究表明:所建立的小型共轴式直升机纵横向通道的理论计算模型能够反映该机悬停状态下纵横向通道的动态特性,以此为基础建立的系统辨识模型可以作为飞行控制系统纵横向通道控制的数学模型.

Using perturbation approach, a linearized flight dynamics model was formulated for the non-linear coaxial helicopter flight control problem. Based on mathematical parametric model of the rotorcraft, the system identification model was obtained by utilizing the input and output data of longitudinal and lateral channel in flight test. The analysis and validation of the above two models in the time domain was given by computer simulation. The stability derivatives, control derivatives and the system eigenvalues were computed for the stability analysis of the helicopter. Results show that the mathematical model can reflect the dynamic characteristics of the longitudinal and lateral channels, based on which the system identification model can be a mathematical model for autonomous flight control system design.