【作者】 杨跃能；

【导师】 吴杰； 郑伟；

【作者基本信息】 国防科学技术大学 ， 航空宇航科学与技术， 2013， 博士

【摘要】 临近空间是指距地面20-100km高度之间的空间范围，包括大气平流层、中间层和部分电离层区域，介于常规航空器的最高飞行高度和航天器的最低轨道高度之间，是跨接航空与航天的新兴领域，其重要价值和战略意义日益凸显。平流层飞艇是指依靠浮升气体提供静升力，依靠推进系统和控制系统实现操纵飞行，长期工作在平流层平均风速较小的高度范围，并执行特定任务的浮空类飞行器。平流层飞艇具有留空时间长、载荷量大、效费比高、隐身性能好、生存能力强等优点，可广泛应用于侦察监视、通信中继、区域导航、环境监测、应急救灾、科学探测等领域，已成为当前航天航空领域的研究热点。平流层飞艇控制系统设计是其研制和工程应用的关键技术之一，同时也是飞行动力学与控制研究领域的重难点问题。论文以解决平流层飞艇飞行控制问题为目的，着重拓展新理论和新方法，系统研究了平流层飞艇动力学建模与控制方法，主要研究成果如下：1、研究了平流层飞艇动力学建模方法，提出了基于运动状态方程特征值和特征向量的模态分析方法，研究了平流层飞艇的动力学特性。1）介绍了平流层飞艇总体方案，定义了描述其空间运动的坐标系和运动参数，分析了作用在其上的力和力矩，综合考虑浮力、重力、空气动力、推力和附加惯性作用，采用Newton-Euler方法建立了平流层飞艇的动力学模型。2）采用小扰动线性化方法推导了平流层飞艇的线性运动方程，应用Lyapunov稳定性判据研究了其运动稳定性：对于给定的未扰运动，小扰动纵向运动和横侧向运动均为渐近稳定的。3）通过计算运动状态方程的特征值和特征向量，研究了平流层飞艇的运动模态：纵向运动由浮沉、浪涌和摆动三种模态叠加而成，横侧向运动由偏航衰减、侧滑衰减和滚转振荡三种模态叠加而成。2、针对平流层飞艇姿态运动非线性、通道耦合、易受外界扰动等特点，提出了一种反馈线性化终端滑模控制方法，为解决姿态调节控制问题提供了技术方案。1）推导了平流层飞艇的姿态运动方程，通过选取合适的状态向量和控制向量，将其描述为仿射非线性系统。2）采用反馈线性化方法将非线性姿态控制系统线性化解耦为三个通道的线性子系统。3）利用滑模控制对模型参数摄动和外界扰动的鲁棒性设计了姿态控制系统，通过选取终端滑模函数使得控制误差在有限时间内收敛至零，应用Lyapunov稳定性理论证明了闭环系统的稳定性。结果表明：姿态控制系统能够在模型参数摄动和外界扰动条件下以零稳态误差调节至指令姿态角；同指数趋近律滑模控制相比，终端滑模控制能够使控制误差在有限时间内收敛至零，提高了系统的响应速度和控制精度。3、针对平流层飞艇空间运动方程多变量、非线性、模型参数摄动等特点，提出了一种模糊在线调参滑模控制方法，为航迹跟踪控制提供了解决方案。1）描述了平流层飞艇航迹跟踪控制问题，建立了航迹控制系统模型。2）定义航迹跟踪误差和滑动模态，采用滑模控制方法设计了航迹控制系统，应用Lyapunov稳定性理论证明了闭环系统的稳定性。3）为解决滑模控制导致的抖振问题，设计了模糊在线调参滑模控制系统，以滑模面为模糊输入变量，以控制参数为模糊输出变量设计模糊控制器，通过模糊规则在线调整控制参数。结果表明：航迹控制系统能够在模型参数摄动和外界扰动条件下准确跟踪参数化指令航迹；同滑模控制相比，模糊在线调参滑模控制能够根据系统状态变化，通过模糊规则在线调节控制参数，有效地削弱了滑模控制导致的抖振。4、针对平流层飞艇长期驻空的任务需求，提出了一种模糊自适应滑模控制方法，为解决区域驻留控制问题提供了参考方案。1）描述了平流层飞艇区域驻留问题，建立了区域驻留控制系统模型。2）定义驻留控制误差和滑动模态，采用滑模控制方法设计了驻留控制系统。3）为解决平流层飞艇模型不确定问题，设计了模糊自适应滑模控制系统，采用模糊系统精确逼近不确定模型，通过自适应律实时调整模糊系统的最优逼近参数，应用Lyapunov稳定性理论证明了闭环系统的稳定性。结果表明：模糊自适应滑模控制能够在模型不确定和外界扰动条件下实现区域驻留控制；同滑模控制相比，模糊自适应滑模控制通过对不确定模型的精确逼近，提高了区域驻留控制精度。论文研究拓展了现有飞行力学理论的研究范畴，发展了平流层飞艇的动力学与控制理论、模型和方法，具有一定的理论意义；论文研究的姿态调节、航迹跟踪和区域驻留控制方法，为解决平流层飞艇控制重难点问题提供了理论基础和技术支持，对飞行控制系统设计具有重要的工程应用价值；论文研究中所发展的各种理论和方法不仅适用于平流层飞艇，还可拓展至高空气球、浮升组合式飞行器等领域，对构建平流层浮空器飞行动力学与控制理论体系，推动临近空间低速飞行器的发展与应用具有重要意义。更多还原

【Abstract】 Near space is quantitatively defined as the range of earth altitudes from20km to100km, below which aerial aircraft can produce sufficient lift for steady flight, andabove which the atmosphere is rarefied enough for satellites to orbit with meaningfullifetimes. There is a growing worldwide interest in a new concept consisting of usingautonomous fight vehicles as platforms operating for extended periods of time at analtitude around20km to accomplish various missions. As a typical lighter-than-airvehicle, the stratospheric airship has an enormous, yet untapped potential as low-speed,or even steady platforms for many different applications, such as reconnaissance,surveillance, telecommunication, broadcasting relays, region navigation, environmentalmonitoring, disaster aid, scientific exploration, and so on.With the rapid progress of airship technologies, advanced flight control system playsa key role in the development of the stratospheric airship. Dynamic nonlinearity, modeluncertainties, and external disturbances contribute to the difficulty in maneuvering anairship to accomplish various missions. Therefore, flight control remains a keytheoretical and technical challenge for the stratospheric airship. For the purpose ofsolving the flight control application problems and further developing the new theoryand methods, this dissertation studies the dynamic model, the dynamic characteristics,the attitude regulation problem, the trajectory-tracking problem, and the station-keepingproblem of the stratospheric airship. The main results achieved in this dissertation aresummarized as follows.1. The dynamic model of the stratospheric airship is derived, the mode analysismethod based on eigenvalue and eigenvector of the state equations is proposed, and thedynamic characteristics of the airship are investigated.1) A conceptual design for thestratospheric airship is presented; reference frames and motion variables of the airshipare defined, and the nonlinear dynamic model of the airship is derived by using theNewton-Euler formulation.2) The approximate linear model is derived from thenonlinear dynamic model under the “small perturbation” assumption, and stability of theairship is analyzed by means of Lyapunov stability theorem.3) The mode analysismethod is proposed, and the motion modes of the airship are investigated. Thelongitudinal motion includes the heave mode, surge mode and pendulum mode, whereasthe lateral motion includes the yaw mode, slideslip mode and roll oscillation mode.2. A novel attitude control approach for the stratospheric airship using feedbacklinearization and terminal sliding mode control (TSMC) is proposed.1) The attitudemotion equations of the airship is derived, and expressed as an affine nonlinear system.2) The nonlinear attitude control system is decoupled into three single-inputsingle-output linear subsystems via feedback linearization.3) The attitude controller is designed based on the new linear systems using TSMC, and the global stability of theclosed-loop system is proven by using the Lyapunov stability theorem. Simulationresults demonstrate that the attitude control system tracks the commanded angleprecisely in the presence of model uncertainty and external disturbance. Contrastingsimulation results indicate that the proposed control approach enables the control errorconverges to zero in a finite time, and has better performance against the SMC.3. A fuzzy parameter-tuning sliding mode control (FPTSMC) approach fortrajectory-tracking control of the stratospheric airship is proposed.1) The problem oftrajectory-tracking control of the airship is formulated, and the model of trajectorycontrol system is derived.2) The SMC is designed to track a time-varying referencetrajectory for its robustness against parametric uncertainty.3) To attenuate thechattering results from SMC, a FPTSMC is proposed in which the control parametersare tuned according to the fuzzy rules, with switching sliding surface function as fuzzycontrol inputs and control parameters as fuzzy control outputs. The stability of theclosed-loop control system is proven using the Lyapunov stability theorem. Simulationresults demonstrate that the FPTSMC performs well in terms of the stability androbustness of trajectory-tracking control despite of model uncertainty and externaldisturbance. Contrasting simulation results indicate that the FPTSMC attenuates thechattering effectively and has better performance against the SMC.4. A fuzzy adaptive sliding mode control (FASMC) approach for station keepingcontrol of the stratospheric airship is proposed.1) The station-keeping control problemof the airship is formulated, and the model of station-keeping control system is derived.2) The SMC is designed under the assumption that the airship model is accuratelyknown.3) In order to solve the problem of model uncertainty, a fuzzy system is used toapproximate the uncertain model of the airship, and an adaptive law is adopted to tunethe optimal parameter vector. The stability of the closed-loop control system is provenvia the Lyapunov stability theorem. The effectiveness and robustness of the proposedcontrol approach is demonstrated via simulation studies. Contrasting simulation resultsindicate that the FASMC has better performance against the SMC.This dissertation expands the research domain of the current flight control theory bydeveloping the dynamic model, control theory, methods and approaches, which haveboth theoretical innovation and technique significance, and provides a promisingapproach for flight control system design of the stratospheric airship. The research workhas high application value in near space aerostatic vehicle and other near spaceapplication projects.更多还原