面向飞行品质要求的非线性约束控制设计方法研究

A variety of nonlinear flight control approaches has been developed to deal with the highly nonlinear and uncertain aerodynamics throughout an ever increasing flight envelope with the aim of achieving extreme maneuverability. However, one of the main drawbacks is that few researchers considering the flying and/or handling qualities during the controller design phase. This proposal is intend to accommodate the specifications of flying and/or handling qualities as the constraints on control variables, where the flight control systems (FCS) could be transformed into a constrained control problem. The realizations of the proposal are described as follows. First, a theoretical analysis on current specifications of flying qualities is taken into account to acquire a collection of constraints on control variables. Then, a nonlinear backstepping contained control based on barrier Lyapunov functions is integrated to implement the control constraints while splines functions with neural networks are chosen to approximate the uncertain aerodynamic forces and moments inside the backstepping control law. In the end, simulation studies on the performances of the FCS and the evaluation of flying qualitieswould be scheduled to verify the feasibility of the proposal, especially the idea of imposing the flying qualities as the conductor of designing the nonlinear flight control law. The anticipated benefit of this proposal can be briefly stated as building a direct connection between the assignments of FCS and the specifications of flying qualities, which also will promote the applications of nonlinear flight control into aerospace engineering.

目前关于飞行控制律的研究，对非线性控制方法如何满足飞行品质规范要求，以及依据飞行品质规范指导非线性控制律设计的研究极少，是制约非线性控制理论应用于飞行控制系统设计的主要障碍之一。本项目旨在将飞行品质的规范要求转化为飞行控制系统设计的约束控制问题。首先，从飞行品质规范出发，研究飞行品质要求与飞行控制系统性能的内在约束机理，获得满足飞行品质要求的约束条件集，为非线性控制律设计提供理论依据。其次，选取合理的控制变量约束条件，设计非线性约束控制策略；考虑气动参数不确定性因素，设计气动参数在线辨识算法，综合设计非线性自适应约束控制策略。最后，通过非线性仿真和飞行品质评估，验证非线性控制设计方法对飞行品质规范要求的满足程度，以及当前飞行品质规范对指导非线性飞行控制律设计方法的适用性。项目的开展将系统地建立飞行品质规范要求与非线性飞行控制设计准则的联系，同时可以促进非线性控制理论在工程践中的应用。

本项目研究了面向飞行品质规范系统要求的自适应约束控制方法，首先与飞机系统模型的状态量、输入量以及输出量之间的机理关系；定量描述系统约束变量的数学方法以及相应的理论依据，归纳提炼出简练且可以直接应用于飞控系统设计的状态约束，输入约束和输出约束等。其次，针对飞行品质的复杂多约束、飞机本体气动不确定性、执行机构速率与带宽限制等带来的控制耦合和鲁棒性问题，提出一种适用于一类时变不确定非线性的自适应约束控制算法，可以灵活处理复杂的变量约束，计算膨胀、模型不确定性等问题，并完成稳定性证明；再者，针对飞行品质评估，开发了具有较好通用性、快速性的飞行品质软件，使用F-16飞机模型，对所提出的自适应约束控制方法进行了评估与确认，对存在的问题进行优化与改进；最后，对项目研究过程进行了总结。

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