小型固定翼无人机具有体型小、重量轻、隐蔽性高、成本低廉等优势，在军事和民用领域具有广阔的应用前景。典型的任务场景下，无人机需要跟踪预先设定的轨迹。在实际系统中，无人机的飞行环境中往往存在模型不确定性和外部扰动等，并考虑到实际控制问题的动态性能要求，对于受扰动的小型固定翼无人机，设计鲁棒、快速稳定的航迹跟踪控制方案是具有重要的实际意义。此外，随着单机控制技术的日渐成熟完善和任务场景的复杂化，无人机的编队控制研究吸引了很多研究者的关注，如何设计和实现快速稳定的编队控制策略也是一个重要的课题方向。基于以上两方面的因素，本文主要的研究工作包括：1. 搭建了一套小型固定翼无人机群实验平台和硬件在环仿真平台，为小型固定翼无人机的飞行控制研究提供了实验验证平台。2. 完成了小型固定翼无人机的动力学建模，以机理分析和系统辨识相结合的方式，给出了系统模型结构和参数的确定过程。采用时域中的方程误差法进行参数辨识，并用实验数据进行了模型匹配度的校验。3. 对存在不确定性和外部扰动的小型固定翼无人机有限时间航迹跟踪控制问题进行了研究。将固定翼无人机的航迹跟踪控制问题，分解为外环的位置控制和内环的姿态控制，基于反馈线性化推导了二阶受扰系统模型，其中集总不确定性的界与系统的状态、控制输入以及外部扰动相关。基于反步控制和鲁棒滤波补偿的思想，设计了鲁棒有限时间控制器，给出了鲁棒有限时间收敛特性的分析和证明，并通过仿真和实验平台对控制器的有效性进行了验证。4. 对固定翼无人机群系统的有限时间编队控制问题进行了研究。基于一致性理论设计了有限时间编队控制策略，并考虑了编队中心参考航迹可指定的情形，设计了有限时间编队航迹跟踪控制协议，最终通过仿真和实验进行了编队飞行的实验验证。
Small fixed--wing unmanned aerial vehicles(UAVs) have an extensive application prospect in both military and civilian areas due to their characteristics of small size, lightweight, high crypticity, low cost and so on. In typical mission scenarios, the UAVs aredemanded to track prescribed trajectories. Flight conditions of UAVs in actual physicssystems are often contaminated by model uncertainties and external disturbances, andconsidering the requirements of dynamic performance for actual control problems, it isof great practical significance to design a robust and fast convergent trajectory trackingscheme for disturbed small fixed-wing UAVs. Besides, along with the growing maturityand perfection of stand-alone control techniques and complexity of mission scenarios, cooperative formation control problems of UAV swarm system have drawn wide attentionsof many researchers, it is a significant issue to design and implement a formation controlstrategy of fast convergence speed. Main results and contributions of this work are asfollows:1. A small fixed-wing UAV swarm system experiment testbed and a hardware-inthe-loop simulation platform are built for researches on flight control of small fixed-wingUAVs.2.Dynamic modeling of small fixed-wing UAV is accomplished, and model structure along with parameters are determined by combining mechanism analysis and systemidentification. Utilizing measured data from flight experiment, unknown parameters areestimated by equation error method in time domain, and then matching degree of identified model is verified using experiment data.3.The finite-time trajectory tracking control problem for small fixed-wing UAV withmodel uncertainty and external disturbances is considered. The problem of trajectorytracking control is decomposed into outer loop position control and inner loop attitudecontrol. Second order disturbed model is derived by feedback linearizion technique and itis shown that the lumped uncertainty is related to system states, control input and externaldisturbances. Based on back-stepping control and robust compensation, a robust finitetime controller is designed, and the analysis and proof of robust finite-time convergenceare given. In order to validate the effectiveness of proposed controller, simulation andactual flight experiments are carried out.4. Finite-time formation control of fixed-wing UAV swarm system is investigated.A finite-time formation control strategy is designed based on consistency theory, and isextended to the circumstance that reference trajectory of the swarm center can be specifiedbeforehand. Then both simulation and actual formation flight experiments are conductedto testify the finite-time formation trajectory tracking protocol.
