某空气舵系统非线性建模及参数识别

Nonlinear modeling and parameter identification of an air rudder system

可靠的空气舵系统动力学模型对飞行控制系统设计非常重要。以某飞行器空气舵系统为对象,考虑运动副间隙和摩擦,研究系统非线性动力学建模问题。分别基于Coulomb摩擦模型和Stribeck摩擦模型建立了系统的四参数和六参数动力学模型;采用系统频响测试数据和参数辨识方法考察了模型的可靠性;改进Coulomb摩擦模型,提出系统的五参数非线性动力学模型。研究结果表明,用五参数模型拟合不同工况测试数据,获得的系统参数一致性优于四参数和六参数模型,可靠性更高。

A reliable dynamic model of air rudder systems is essentially important for the flight control system design.In this paper,the nonlinear modeling of a launch vehicle air rudder system with joint clearance and friction is studied.A four-parameter dynamic model and a six-parameter dynamic model with free-play and friction are presented by adopting Coulomb friction and Stribeck fric-tion,respectively.Their reliability is investigated by applying physical parameter identification method to the frequency response test data.An improved five-parameter nonlinear dynamic model is proposed based on a modified Coulomb friction.It is found that,the parameters of the five-parameter model identified via different tests show better consistency than the four-parameter and six-pa-rameter models.Thus the five-parameter model is more reliable.