参数估计的样条函数法应用

Application of Spline Method for Parameter Estimation

简要地介绍了样条函数法的基本原理、飞机的数学模型和空气动力系数的样条函数表达式。用一算例说明了估计过程，获得了纵向气动导数随迎角变化的估计结果。同时还研究了迎角节点间隔和样条函数的次数对估计结果的影响。估计结果表明，样条函数法是非线性参数估计的重要方法之一。适当减小节点的间隔和适当增加样条函数次数可以提高参数估计的精度。

Basic principle of spline method and mathematical model of aircraft and spline expression of aerodynamic coefficient are simply presented. The estimation procedure is shown by using an example and the estimation results of variation of longitudinal aerodynamic derivatives with angle of attack are obtained. The influence of nodal points interval of angle of attack and order of spline function on estimation results is also researched. The estimation result show that spline function method is one of important methods for nonlinear parameter estimation. When nodal points interval is properly reduced and order of spline function is properly increased, then parameter estimation ac curacy can be improved.