电动空气舵执行机构建模与参数辨识

Modeling and Parameter Identification of an Aircraft Rudder System with an Electromechanical Actuator

针对使用机电作动器(EMA)的飞行器空气舵执行机构模型确认需求,考虑舵轴弹性及机构中的干摩擦,通过综合两自由度(DOF)开环动力学方程和EMA伺服系统PID控制器,建立了执行机构五阶传递函数(TF)模型。根据TF特征,提出了模型参数约束条件下,采用频率响应函数(FRF)测量数据辨识TF模型参数的改进正交多项式拟合法,完成了参数辨识。辨识结果表明:两自由度动力学模型比一般广泛采用的单自由度模型更准确地反映了空气舵执行机构动力学特征;本文提出的改进正交多项式拟合法可以实现位置跟踪系统TF参数辨识,辨识模型FRF曲线与实测数据吻合良好。

In this paper, modeling and parameter identification of an aircraft rudder system with an electromechanical actuator （EMA） is discussed to validate its mathematical model through frequency response function （FRF） test. Firstly, a five order transfer function （TF） model of the rudder system is established by synthesizing its two-degree-of-freedom （DOF） dynamic equations and a servo PID controller, in which the rudder axis is modeled as a damped spring and the Coulomb friction is also included. Then, in view of the characteristics of the TF model, an improved parameter identification method based on the rational fraction orthogonal polynomials with a parameter constraint is presented. Finally, the TF parameters are identified by applying the presented method to the FRF test data. It is indicated by the identification results that, 1 ） the two-DOF model figures the rudder system better than the generally used one-DOF one, and 2） excellent agreement is achieved between the identified mathematical model and the FRF measurement data, which demonstrates the efficacy of the proposed TF parameter identification method for the position tracking systems.