吸气式激光推力器概念设计

以发射10kg级微小卫星为航天任务背景,基于地面推力1000N的设计指标,分析了吸气式激光推进的主要性能参数,依据所建立的激光推进能量相似律理论和数值计算研究结果,对激光参数、聚焦系统和喷管子系统进行设计,完成了封闭的吸气式激光推力器概念设计循环。所提出的二次反射聚焦系统与抛物形喷管组合的吸气式激光推力器概念模型经数值计算程序验证,可以获得地面500N/MW的冲量耦合系数。所提出的设计理论和方法对激光推力器概念设计有一定的参考价值,是研制激光推力器模型的重要基础。     

目标机动加速度的估计与导引律实现

研究了寻的末制导过程的制导信息获取问题,并在此基础上对导引规律的实现进行了 研究。针对末制导过程的非线性数学模型的特点,设计了高增益观测器,采用高增益反馈保 证观测误差的快速收敛,利用导弹导引头提供的信息,对导引规律中需要的视线转率和目标 机动加速度信息进行了估计,分析了观测器误差的收敛性。采用观测器方法进行制导信息的 估计,将目标机动看作外部扰动输入,因而不需要建立目标的机动模型或对目标机动的统计 特性进行假设。利用观测器获得的制导信息,对导引规律进行了实现,并证明了闭环制导回 路的稳定性。最后进行了数值仿真,并对仿真结果进行了分析,验证了文中得出的结论。     

基于观测器的航天器执行机构失效故障重构

针对刚体航天器在轨运行时存在执行机构失效故障和外部干扰问题,提出了一种基于观测器的故障检测与重构方法。该方法运用迭代学习技术,利用上一步的执行机构故障观测信息来估计当前的故障信息,并最终实现故障的精确重构。此外基于Lyapunov方法从理论上证明了此故障诊断方法能够实时、在线地实现对常值、时变甚至随机型的执行机构失效故障的重构,并且对外干扰力矩具有一定的鲁棒性。最后,仿真结果验证了该方法的有效性。
     

装药几何参数不确定性优化设计

1引言固体火箭发动机装药设计,一般要求在满足发动机内弹道性能和相关约束条件下,选择药型并确定其几何参数,同时综合考虑燃烧室壳体内部绝热层、衬层和人工脱粘层的设计要求。装药设计作为发动机设计的核心,其设计质量很大程度决定了发动机性能优劣。航天飞机固体助推火箭发动     

A finite-time 3D guidance law based on fixed-time convergence disturbance observer

In order to achieve accurate interception of high-speed maneuvering targets, this paper presents a relative Line-of-Sight (LOS) velocity based finite-time three-dimensional guidance law design framework, and discusses the application of fixed-time convergence disturbance observer in this framework. Firstly, a simple Lyapunov function is provided to show that the coupled terms in the relative kinematics can be ignored in the proposed guidance law design framework. Secondly, the realizations of several classical guidance laws are analyzed with the proposed framework, including TPN guidance law, finite-time Input-to-State Stability (ISS) guidance law, and sliding mode guidance law. Thirdly, fixed-time convergence disturbance observers are introduced to design the composite finite-time 3D guidance law, and Lyapunov method is employed to show the stability of the guidance system. Numerical simulations with different scenarios show that the proposed generalized guidance law performs high interception accuracy.     

微小型直升机自抗扰飞行控制

针对微小型直升机建模困难,动态模型中不仅含有较多的未知动态,且飞行中内外扰动均比较大的问题,提出一种基于自抗扰控制的飞行控制方法。该方法不仅可以确保微小型直升机六自由度方向上的稳定准确跟踪控制,而且可实时估计并补偿未知动态影响。通过盘旋上升模态下飞行仿真验证了此控制方法的有效性和鲁棒性。     

基于故障观测器的无人机直接自修复控制

提出一种基于故障观测器的无人机直接自修复控制。首先,根据系统本身存在的故障,设计了一个非线性故障观测器对其进行观测。其次,设计了一个快速终端滑模面和直接自修复控制器,将指数函数和符号函数引入到新型滑模面里。同时引入了自适应技术,对不确定的故障估计其上界。最后,通过对无人机进行了相应的仿真数值验证得出所提方法的有效性。     

一个Modified Chen系统的混沌同步与加密

引进Observer同步方案,ModifiedChen混沌动力系统达到了较好的同步效果。两个已同步的ModifiedChen系统分别作为通信系统的传输器和接收器,分别利用两种不同的方式将信号加到传输端,实现了安全通信巾的加密与解密,从而验证了Observer混沌同步方案在安全通信系统中的有效性。     

利用特征结构指定隔离卫星滚动偏航陀螺故障的新方法

对于卫星滚动轴陀螺和偏航轴陀螺的故障隔离,给出了一种新的方法。利用姿态运动学的关系建立关联卫星各个敏感器输出信息的系统,对于这个系统设计隔离观测器,使不同陀螺的故障在残差空间的不同方向定向,达到故障隔离的目的。文中给出了隔离观测器存在的一个充分条件和求解步骤。最后的数学仿真表明这种方法能够有效地隔离滚动陀螺和偏航陀螺故障。     

Data-driven model-free adaptive attitude control of partially constrained combined spacecraft with external disturbances and input saturation

This study presents an improved data-driven Model-Free Adaptive Control(MFAC)strategy for attitude stabilization of a partially constrained combined spacecraft with external disturbances and input saturation. First, a novel dynamic linearization data model for the partially constrained combined spacecraft with external disturbances is established. The generalized disturbances composed of external disturbances and dynamic linearization errors are then reconstructed by a Discrete Extended State Observer(DESO). With the dynamic linearization data model and reconstructed information, a DESO-MFAC strategy for the combined spacecraft is proposed based only on input and output data. Next, the input saturation is overcome by introducing an antiwindup compensator. Finally, numerical simulations are carried out to demonstrate the effectiveness and feasibility of the proposed controller when the dynamic properties of the partially constrained combined spacecraft are completely unknown.