基于自适应动态规划的运载火箭智能姿态容错控制

针对运作火箭主动段发动机摆动执行机构故障下的姿态控制问题,结合自适应动态规划（ADP）方法设计了一种智能容错控制策略。该智能容错控制器主要包括2部分：容错稳定控制部分和优化补偿部分。容错稳定控制部分利用自适应和滑模变结构控制设计,主要维持执行机构故障下姿态控制系统的稳定,保证姿态跟踪误差的有限时间收敛;优化补偿部分采用执行-评价结构,利用ADP的在线学习优势,根据姿态系统的跟踪误差（尤其是系统故障、强干扰导致的跟踪偏差）,设计ADP算法产生补偿控制来进一步优化姿态控制系统的跟踪性能。仿真验证表明,即使存在外部干扰和执行机构故障的情况下,所提方法仍能保证系统稳定且精确跟踪指令信号。     

SE(3)上航天器姿轨耦合固定时间容错控制

针对相对运动航天器姿轨一体化控制问题,考虑执行器故障和控制输入饱和的影响,提出了一种基于滑模的模糊自适应固定时间容错控制方法。首先,在李群SE（3）的框架下建立并推导相对运动航天器姿轨一体化误差动力学模型;其次,引入执行器故障和控制输入饱和的问题,采用双幂次快速终端滑模面,并结合模糊自适应方法设计了固定时间稳定的容错控制器,可以实现执行器故障情况下相对运动航天器的高精度快速跟踪控制;然后,运用Lyapunov方法证明了系统的稳定性,该控制器不仅能不依赖于系统的初始状态实现滑模趋近和到达阶段的固定时间稳定性,而且由于采用模糊逼近方法结合自适应更新策略可以实时高精度地估计系统的总扰动信息,因此可以达到快速高精度的容错控制目标;最后,对所提出的的控制方法进行数值仿真分析,结果验证了该方法的有效性和可行性。     

Singular formalism and admissible control of spacecraft with rotating flexible solar array

This paper is concerned with the attitude control of a three-axis-stabilized spacecraft which consists of a central rigid body and a flexible sun-tracking solar array driven by a solar array drive assembly. Based on the linearization of the dynamics of the spacecraft and the modal identi- ties about the flexible and rigid coupling matrices, the spacecraft attitude dynamics is reduced to a formally singular system with periodically varying parameters, which is quite different from a space- craft with fixed appendages. In the framework of the singular control theory, the regularity and impulse-freeness of the singular system is analyzed and then admissible attitude controllers are designed by Lyapunov＇s method. To improve the robustness against system uncertainties, an H∞ optimal control is designed by optimizing the H∞ norm of the system transfer function matrix. Comparative numerical experiments are performed to verify the theoretical results.     

Nonlinear control and stability analysis of spacecraft attitude recovery

The problem of automated attitude recovery of rigid and flexible spacecraft is investigated using feedback linearization control and a novel approach for generating the control error signal based on quaternion addition. The attitude and flexible dynamics equations for a class of spacecraft is presented. The resulting nonlinear and coupled equations of the system are implemented into a high-fidelity user-friendly simulation environment. The simulator is used for the investigation of attitude recovery of flexible spacecraft using the feedback linearization approach. Since the flexible spacecraft is underactuated, the input-output linearization technique was specifically used to break up the system into two distinct parts, namely 1) an external linearizable system for which a linear controller can be easily implemented, and 2) an internal nonlinear unobservable system for which the associated zero dynamics is shown to be asymptotically stable for two representative cases. The overall closed-loop stability of the flexible spacecraft is analyzed rigorously and shown to be asymptotically stable using Lyapunov's method     

高可靠电机系统主动变结构与容错控制技术

为了更好地、更高性能地适应航天器多极端工况对伺服系统输出特性的需求变化以及高可靠应用需求,提出了一种新型高可靠电机系统,其主要包括变结构控制器、可变结构驱动拓扑和变结构容错电机。根据系统所需,通过在线变换驱动器与电机绕组的连接方式,重构电机系统结构和参数,进而改变电机系统的输出性能,最终实现每个工况下均能达到航天任务所需性能最优的目的;在驱动器或者电机绕组发生故障时,亦可通过电机系统结构变换,将故障进行隔离并进行容错控制,让剩余的正常部分还能输出所需的扭矩,实现电机系统的带故障运行,保证系统具有故障-工作的高可靠性能力。     

卫星姿态控制系统容错控制综述

主要针对卫星姿态系统容错控制研究领域已有的成果进行了回顾。总结了国内外卫星容错控制的现有成果,主要从卫星姿态控制系统的可重构性、单体卫星容错控制和卫星编队容错控制3个部分对相关的研究成果进行了归纳分析。其中,卫星姿态系统的可重构性从重构目标和系统功能要求两方面进行分析;对单体卫星容错控制现状的介绍主要从自适应技术、滑模理论、预设性能、干扰观测器、故障估计观测器几个方面展开;卫星编队容错控制方法从独立容错、协同容错、拓扑重构和组成重构的角度进行阐述。最后进行总结,并展望了卫星姿态控制系统容错控制领域未来可能出现的新问题和研究思路。     

Composite control method for stabilizing spacecraft attitude in terms of Rodrigues parameters

In this paper, the attitude stabilization problem of a rigid spacecraft described by Rodrigues parameters is investigated via a composite control strategy, which combines a feedback control law designed by a finite time control technique with a feedforward compensator based on a linear disturbance observer (DOB) method. By choosing a suitable coordinate transformation, the spacecraft dynamics can be divided into three second-order subsystems. Each subsystem includes a certain part and an uncertain part. By using the finite time control technique, a continuous finite time controller is designed for the certain part. The uncertain part is considered to be a lumped disturbance, which is estimated by a DOB, and a corresponding feedforward design is then implemented to compensate the disturbance. Simulation results are employed to confirm the effectiveness of the proposed approach.     

Adaptive fault-tolerant attitude tracking control for spacecraft with time-varying inertia uncertainties

This paper is devoted to adaptive attitude tracking control for rigid spacecraft in the presence of parametric uncertainties, actuator faults and external disturbance. Specifically, a dynamic model is established based on one-tank spacecraft, which explicitly takes into account changing Center of Mass(CM). Then, a control scheme is proposed to achieve attitude tracking.Benefiting from explicitly considering the changing CM during the controller design process, the proposed scheme possesses good robustness to parametric uncertainties with less fuel consumption.Moreover, a fault-tolerant control algorithm is proposed to accommodate actuator faults with no need of knowing the actuators' fault information. Lyapunov-based analysis is provided and the closed-loop system stability is rigorously proved. Finally, numerical simulations are presented to illustrate the effectiveness of the proposed controllers.     

空间模块化机械手系统容错控制系统研究

研究搭载在空间站或其他近地轨道航天器上的空间模块化机械手系统的容错控制系统.与地面应用环境相比较,空间特殊的应用环境存在许多不同,因而传统工业机械手系统的设计技术不能直接应用于空间机械手系统的设计.考虑到空间应用对系统质量、体积、功耗、研制费用和周期所提出的苛刻要求,主要采用COTS器件设计并实现该空间机械手系统的容错控制系统,介绍了系统的软硬件体系结构及其特点,最后给出系统的性能参数.在系统设计中采用许多已有的设计技巧与工程经验,具有高可靠性和工程实用性.     

基于模态切换的航空发动机容错控制

综合了航空发动机控制和故障诊断方法,设计了基于模态切换的任务级和发动机级模式的容错控制系统.任务级模式在发动机部件故障时,通过切换控制策略和控制模式达到恢复或降低发动机性能的要求;发动机级模式在控制回路失效时,根据故障情况切换到容错控制回路,从而保证发动机继续正常工作.数字仿真结果表明:在稳态或加速过程中出现部件故障时,容错控制系统都能够100%恢复发动机的推力;在发动机中间、慢车和节流状态下,当压气机转速控制回路失效时,容错控制系统能够在3s内平稳切换到风扇转速控制回路.      

挠性航天器大角度机动的滑模变结构控制

考虑刚性主体上带有挠性梁的航天器，在建立挠性系统动力学模型的基础上，采用指数趋近率的滑模变结构控制策略进行大角度机动控制，并通过最优控制理论设计弹性稳态器抑制由于刚体运动而激发的弹性振动，数字仿真表明，提出的控制策略在实现旋转机动的同时，有效地抑制了弹性振动。     

基于鲁棒故障观测器的非线性离散系统容错控制设计

针对存在执行器故障以及未知干扰的非线性离散系统,提出了一种鲁棒故障估计与容错控制方法。首先在未知系统干扰作用下,设计鲁棒故障观测器实现系统状态和执行器故障的同步估计;然后根据鲁棒故障观测器得到的系统状态估计和故障估计信息设计容错控制器,进行状态反馈容错控制,同时基于D稳定与H_∞控制理论对鲁棒故障观测器和容错控制器进行设计,实现了多约束条件下的故障估计与容错控制;最后用飞行控制系统模型验证了所提方法的有效性。     

航天器有限时间自适应姿态跟踪容错控制

非刚体航天器存在时变的惯量、执行器完全失效或衰退故障以及外界干扰的情况,提出一种有限时间自适应姿态跟踪容错控制方法。首先,基于有限时间理论和自适应方法,设计惯量不确定性自适应估计项和外界干扰参数自适应估计项进行系统补偿,克服惯量不确定性和抑制外界干扰;然后,基于容错控制和双幂次方法,设计一种自适应有限时间姿态跟踪容错控制算法,并且利用Lyapunov稳定性理论证明所提算法能够保证航天器姿态跟踪系统实际有限时间稳定;最后,对仿真结果进行验证。结果表明:所提有限时间姿态跟踪容错控制方法是有效的。     

应用分力合成主动振动抑制方法的最优飞行器大角度机动控制策略

 针对当代带大型挠性附件的空间飞行器,提出了分力合成主动振动抑制方法,并且分析了方法的鲁棒性。该方法可以保证挠性飞行器在实现指定的刚体运动的同时,抑制掉对系统影响较大的挠性振动模态,对频率不确定性的鲁棒性使得该方法易于工程实践。对于使用常幅值力矩喷气执行机构的航天器,设计了应用分力合成方法的时间—燃料最优机动控制律,数值仿真结果验证了方法的有效性。     

基于状态反馈的执行器故障容错控制

针对线性离散系统的执行器故障,提出了一种基于状态反馈的容错控制方法。该方法在应用自适应卡尔曼滤波进行系统状态和故障同步估计的基础上,通过故障信息和状态估计进行状态反馈,对闭环系统进行极点配置,从而修正执行器故障造成的系统误差,实现容错控制。最后,将该方法应用于飞行控制系统的执行器故障容错控制,仿真结果表明该方法不仅能够准确地进行故障估计,而且能够在故障情况下保证系统输出正常,具有一定的理论意义和实际工程应用价值。     

基于分布式自适应的多智能体容错一致性控制

针对"领航者-跟随者"的多智能体编队，由于领航者系统出现故障引起编队通讯中断而不能完成任务的问题，提出了一种基于一致性理论的分布式自适应控制方法，用于解决该问题。首先，以一个位于顶点的智能体作为领航者，其余3个位于同一条线上的智能体作为跟随者，由此所构成的三角形编队作为被控对象。其中，领航者速度方向作为编队的前行方向，跟随者位于领航者之后。其次，基于图论，对智能体局部信息参数进行分布式自适应更新，并设计分布式自适应控制律，用于弥补多智能体编队中领航者故障所造成的影响。同时，根据相邻智能体的局部信息，设计整体分布式自适应容错控制律，进一步通过构建合理的Lyapunov函数，证明所设计控制器的稳定性，以及"领航者-跟随者"之间相对横向以及相对纵向的距离误差均收敛于固定常数。最后，仿真验证表明：所提出的自适应控制方法具有良好的鲁棒性，这也为工程实践提供了理论依据。     

刚体飞行器大角度机动的反馈非线性化控制

研究了刚体飞行器大角度的姿态控制问题,采用四元数描述刚体姿态,建立了刚体姿态运动的数学模型。基于反馈非线性化技术,通过构造李雅普诺夫函数推导出标量增益的线性控制律和矩阵增益的非线性控制律。两种控制律不需要知道系统参数,对模型误差具有鲁棒性。理论分析和仿真结果表明,所求控制律对闭环系统具有全局渐近稳定性。     

Delay Depending Decentralized Adaptive Attitude Synchronization Tracking Control of Spacecraft Formation

This paper deals with the problem of cooperative attitude tracking with time-varying communication delays as well as the delays between inter-synchronization control parts and self-tracking control parts in the spacecraft formation flying. First, we present the attitude synchronization tracking control algorithms and analyze the sufficient delay-dependent stability condition with the choice of a Lyapunov function when the angular velocity can be measured. More specifically, a class of linear filters is developed to derive an output feedback control law without having direct information of the angular velocity, which is significant for practical applications with low-cost configurations of spacecraft. Using a well-chosen Lyapunov-Krasovskii function, it is proven that the presented control law can make the spacecraft formation attitude tracking system synchronous and achieve exponential stability, in the face of model uncertainties, as well as non-uniform time-varying delays in communication links and different control parts. Finally, simulation results are presented to demonstrate the effectiveness of the proposed control schemes.     

基于反步法的挠性航天器姿态镇定

利用反步法研究了一类挠性航天器的姿态镇定问题,提出一种基于模态观测器的反步控制设计方案.首先,构造挠性模态观测器对挠性模态变量及其变化率进行观测;其次,将角速度看成虚拟控制器,设计虚拟角速度镇定运动学模型与挠性模态变量组成的子系统;最后,利用反步法设计了一种非线性控制器使得角速度能够跟踪虚拟角速度,从而实现姿态镇定的目...     

Variable structure control and active vibration suppression of flexible spacecraft during attitude maneuver

This paper presents a new approach to vibration reduction of flexible spacecraft during attitude maneuver by using the theory of variable structure control (VSC) to design switching logic for thruster firing and lead zirconate titanate (PZT) as sensor and actuator for active vibration suppression. The spacecraft to be investigated is a hub with a cantilever flexible beam appendage, which can undergo a single axis rotation. The proposed control system includes the attitude controller acting on the rigid hub, designed by variable structure control technique, and the surface-bonded PZT patches for active vibration suppression of flexible appendages, designed by the positive position feedback (PPF) control technique. To avoid chattering, pulse-width pulse-frequency (PWPF) modulation is adopted for the thruster control, which makes the thrusters to be operated in a close to linear manner and also can suppress the relatively large amplitude vibrations excited by, for example, rapid maneuver. However, some residual micro-vibrations still exist due to the switching actions. Upon that, the technique of active vibration control using PZT is turned on to provide further vibration suppression of the residual micro-vibrations and fine tuning of the system performance. By combining the advantages of both these control strategies, an improved performance for vibration control in both the macro-and micro-senses can result. Both analytical and numerical results are presented to show the theoretical and practical merit of this approach.