空天飞行器轨迹规划与控制研究

发布时间：2018-01-01 06:12

  本文关键词：空天飞行器轨迹规划与控制研究　出处：《国防科学技术大学》2015年博士论文　论文类型：学位论文

  更多相关文章： 空天飞行器 轨迹规划与控制 改进伪谱法 微分平坦 同伦法 不确定性 随机配点 微分变换 有限时间控制 电磁编队 滑翔飞行器

【摘要】：近年来,随着高超声速飞行器、空间机器人等新型空天飞行器的快速发展,对空天飞行任务的灵活性、适应性和安全性提出了更高的要求,因而任务规划成为当前空天领域研究热点。空天飞行器轨迹规划与控制具有状态变量维数高、约束多、耦合性和不确定性强等特点,在理论和技术实现上均提出了一定挑战。论文深入研究了空天飞行器最优轨迹规划、在线轨迹规划、不确定性轨迹规划以及非线性鲁棒控制等方法,并应用于航天器电磁编队构形重构和高超声速滑翔飞行器再入飞行。论文由理论和应用研究两部分组成,理论研究部分重点围绕优化规划策略、提高求解效率和处理不确定性影响等问题展开:(一)考虑性能指标优化需求,在最优控制理论框架下,建立了最优轨迹规划问题的数学模型,采用分段Radau伪谱法将其转换为非线性规划问题求解;进而,针对Radau伪谱法求解Bang-Bang控制轨迹的不足,提出了基于协态映射定理和极大值原理的控制切换结构检测策略,并利用Radau伪谱积分矩阵逐段将微分约束转换为代数约束,仿真结果验证了该方法的有效性。(二)考虑规划效率与精度要求,利用系统微分平坦属性,将问题转换为平坦输出规划问题,消除了微分动力学约束且降低了规划空间维数;进一步,采用Chebyshev伪谱法参数化平坦输出,并综合共形映射和重心有理插值技术进行改进,有效降低了微分矩阵病态特性对规划精度的影响。研究了微分平坦-解析同伦组合优化方法,基于平坦方法生成的光滑轨迹构建协态变量解析为零的辅助问题,化解了同伦法的初始化困难,同时提高了平坦方法对非光滑轨迹的适用性。(三)考虑不确定性对轨迹规划的影响,分析了空天飞行器的主要不确定性;针对强非线性动态系统,研究了基于随机配点的不确定性分析方法,并与Monte Carlo法对比,验证了前者的估算精度及计算效率优势。构建了轨迹稳健性指标,并基于双层嵌套式不确定性规划框架建立多目标优化模型,以综合考虑稳健性指标和初始性能指标;仿真表明该方法能够有效降低轨迹对不确定性的灵敏度。(四)研究利用反馈跟踪控制消除不确定性影响的方法:考虑控制能量与跟踪效果,采用滚动时域方法设计了鲁棒最优跟踪控制律,并提出了求解有限时域两点边值问题的微分变换方法;考虑跟踪偏差收敛时间,采用自适应终端滑模控制设计了有效时间跟踪控制律;仿真验证了两种跟踪控制律的有效性与鲁棒性。论文应用部分围绕航天器电磁编队和高超声速滑翔飞行器展开:(一)针对电磁编队构形重构任务,考虑系统动力学的强耦合性,分别采用自由磁偶极子解耦策略+Radau伪谱法和间接控制变量解耦策略+微分平坦方法的规划框架,设计了双星和三星编队的最优构形重构轨迹;考虑系统的非线性和不确定性,设计了基于反馈线性化和自适应终端滑模控制方法的内外环组合控制策略,并仿真验证了构形重构控制律的鲁棒性与有限时间收敛性。(二)针对高超声速滑翔式再入飞行任务,在无量纲地心距-速度剖面内,建立了过载、动压和热流密度三类过程约束的统一数学规律,推导了倾侧角闭环解析解,并基于恒定过程约束飞行的策略生成了三自由度再入飞行轨迹。在状态空间中,采用微分平坦方法快速优化滑翔飞行轨迹,并设计了滚动时域鲁棒最优跟踪控制律。数值仿真验证了两种标称轨迹生成方法的有效性以及滚动时域跟踪控制律的鲁棒性。总之,论文系统研究了空天飞行器轨迹规划与控制的理论方法,并针对航天器电磁编队构形重构和高超声速滑翔飞行任务进行了设计分析。论文研究在最优轨迹规划、在线轨迹规划、不确定性轨迹规划以及非线性鲁棒跟踪控制等方面取得了一些研究成果,为进一步深入研究奠定了坚实基础。
[Abstract]:In recent years, with the rapid development of hypersonic vehicle, space robot model of spacecraft of the space flight mission, flexibility, put forward higher requirements for adaptability and security, so the task planning has become a hot topic in the research field of aerospace. Trajectory planning and control of the state variable dimension is high, the coupling characteristics of multi constraints. With strong uncertainty, some challenges were made in the implementation of the theory and technology. This paper further studies the spacecraft trajectory planning, trajectory planning, trajectory planning uncertainty and nonlinear robust control method is applied to electromagnetic spacecraft formation reconfiguration and hypersonic glide reentry flight. The theory research and application of two parts, part of the theoretical research focuses on the optimization planning strategy, improve the efficiency of problem solving and processing uncertainty Effect of expansion and other issues: (a) performance optimization needs to consider, in the optimal control theory, establishes a mathematical model of optimal trajectory planning problem, using piecewise Radau pseudospectral method to convert it to solve nonlinear programming problems; then, in the Radau pseudospectral method for solving Bang-Bang trajectory control, proposed the co state mapping theorem and the maximum control switch structure detection strategy based on the principle of using Radau integral matrix pseudospectra piecewise differential constraint into algebraic constraints, the simulation results verify the validity of the method. (two) test requirements into account planning efficiency and accuracy, using Differential Flatness property, be changed to flat output programming problem, eliminating the dynamical constraints and reduce the dimension of space planning; further, the Chebyshev pseudo spectral method of parametric flat output, and conformal mapping and barycentric rational interpolation. Operation is improved, can effectively reduce the influence of pathological characteristics on the planning of differential matrix precision. The thesis studied the Differential Flatness analytical homotopy optimization method, smooth trajectory generation method of flat construction co state variables analysis for auxiliary problem zero based on homotopy method to resolve the initialization difficulties, and improve the applicability of the method of non smooth flat track. (three) considering the effect of uncertainty on trajectory planning, analyzes the main uncertainty of spacecraft; for strong nonlinear dynamic system, the stochastic collocation method based on uncertainty analysis, and compared with Monte Carlo method, to verify the accuracy and computational efficiency of constructing trajectory advantage. Robust index, and based on the multi-objective optimization model of double nested uncertainty planning framework is established, by considering the robustness index and initial performance index; the simulation show that the Reduce the sensitivity of the track on the uncertainty of the method. (four) based on feedback tracking control method to eliminate the effects of uncertainty: energy control and tracking effect into account, using the rolling time domain method to design a robust optimal tracking control law, and put forward the differential transform method of problem solving finite domain boundary value; considering the tracking error convergence time, the adaptive terminal sliding mode control design of effective time tracking control law; simulation of the two tracking control law is effective and robust. The application part around the spacecraft electromagnetic formation and hypersonic glide vehicle: (a) the electromagnetic formation reconfiguration task, considering the strong coupling system dynamics, respectively. The free dipole decoupling strategy +Radau pseudospectral method and indirect control variable decoupling strategy + Differential Flatness method planning frame design, the double Optimal and Samsung star formation reconstruction trajectory; considering the system nonlinearity and uncertainty, the design of a feedback control strategy of the combination of the inner and outer ring and adaptive terminal sliding mode control based on linear, and verified the robustness and convergence of the finite time control law reconfiguration. (two) for hypersonic glide reentry flight task in dimensionless range - velocity profile, established a unified mathematical rules of overload, dynamic pressure and heat flux of three kinds of constraints in the process of solution, the bank angle closed loop is derived, and the constant constraint in the process of flight generation strategy based on three degrees of freedom. The reentry trajectory in the state space, the fast glide flight trajectory optimization method and the design of the differential flatness, robust receding horizon optimal tracking control law. Simulation results verify the effectiveness of the two nominal trajectory generation method and rolling time Robust tracking control law. In short, the theory method of trajectory planning and control, and the electromagnetic spacecraft formation reconfiguration and hypersonic glide flight are analyzed. The research on the optimal trajectory planning, online trajectory planning, trajectory planning and tracking control of uncertain nonlinear robust made some research achievements, and laid a solid foundation for further research.

【学位授予单位】：国防科学技术大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：V448.2;V412.4
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本文编号：1363263