基于PEM的飞行操纵系统辨识

为检查飞机飞行操纵系统的动态特性,通常需要开展升降舵、副翼和方向舵操纵系统的地面频率响应试验,用于评估操纵面的反应相对于座舱操纵力输入的相位滞后和时间延迟情况。为进一步了解某型飞机操纵系统的固有频率和阻尼特性,采用预测误差法(简称PEM)基于该型飞机全动平尾操纵系统的地面频率响应试验数据,建立操纵系统的等效模型并辨识模型参数,通过损失函数和最终预测误差(简称FPE)评价模型结构和参数的准确性。系统辨识结果表明,使用二阶传递函数作为飞行操纵系统的等效数学模型,损失函数和最终预测误差较小;等效模型真实反应操纵系统的动态特性,系统固有频率和阻尼比均远大于飞机本体模态运动的频率和阻尼比,满足系统设计要求。

To examine the dynamic characteristics of the flight control system(FCS),ground frequency response tests for elevator,aileron and rudder control systems are required to evaluate the phase lag and time delay of the response of the control surface relative to the cockpit control force input.In order to clarify the natural frequency and damping characteristics of the FCS,the prediction error method(PEM)is used to establish the equivalent model of the FCS and identify the model parameters based on the ground frequency response test data of the pivoted horizontal stabilizer control system of the aircraft,and evaluate the accuracy of the model structure and parameters through the loss function and the final prediction error(FPE).The system identification results show that using the second-order transfer function as the equivalent mathematical model of the flight control system,the loss function and the final prediction error are small,and the equivalent model truly reflects the dynamic characteristics of the control system.The natural frequency and damping ratio of the system are much larger than the frequency and damping ratio of aircraft modal motion,which meet the requirements of system design.