飞行器结构轻量化研究与结构复合材料的发展

本文以结构轻量化为目的，用力学分析方法对结构复合材料的发展进行深入讨论，以揭示其研究和发展与宇航结构应用的相互关联与影响。并探讨如何加强这个课题的研究工作。     

Adaptive fast sliding mode fault tolerant control integrated with disturbance observer for spacecraft attitude stabilization system

In this paper, the problem of fault-tolerant control (FTC) for spacecraft attitude stabilization system with actuator fault and mismatched disturbance is investigated. A novel fault tolerant control strategy based on adaptive fast terminal sliding mode control (AFTSMC) is proposed. Firstly, a novel composite observer is proposed to estimate the disturbance, actuator efficiency factor and partial states of the system. By introducing a sliding mode observer, the bias actuator fault is reconstructed. Subsequently, in accordance with the estimated information, a novel sliding mode fault tolerant controller is designed. The proposed control scheme contains two compensators and two adaptive parameters to attenuate the mismatched disturbance, to compensate actuator fault, and to guarantee fast convergence of the system. Furthermore, the reachability of sliding motion is proved. The simulation results for the spacecraft system illustrate the effectiveness of the proposed method.     

Output-feedback super-twisting control for line-of-sight angles tracking of non-cooperative target spacecraft

Without the line-of-sight (LOS) angles rate information, this paper investigates the LOS angles tracking problem of non-cooperative target in chaser’s body frame with the external disturbance force and torque via chaser’s control torque. By integrating with the attitude dynamics of the chaser, a novel coupled LOS-based relative motion model is firstly established, which reveals the redundancy relationship between the LOS angles motion with two Degree-of-Freedom (DOF) and three dimensional control torque. More specially, the LOS angles tracking control problem is formulated as an output-feedback control problem of an uncertain nonlinear system with the actuator redundancy. As a stepping-stone, a fourth order high order sliding mode observer (HOSMO) is proposed to estimate the system state and uncertain terms. A combination of modified super twisting algorithm (STA) with nonsingular fast terminal sliding mode (NFTSM) and control allocation is proposed, the main novelty of modified STA is that the NFTSM is introduced to replace the linear sliding mode (LSM), and the original STA cannot be applied directly, a modified STA is proposed, which can guarantee the fast finite-time convergence. Finally, simulations are conducted to show fine performance of the proposed control scheme.     

基于剪式陀螺系统的空间飞行器非线性姿态控制

为避免控制力矩陀螺系统奇异,采用三对剪式陀螺垂直安装构形构成一个控制力矩陀螺系统作为空间飞行器姿态控制的执行机构。基于Newton-Euler法推导出剪式陀螺系统操纵空间飞行器姿态运动的精确数学模型,并在此基础上设计空间飞行器大角度姿态机动的非线性控制律,在设计的同时证明系统的稳定性。对剪式陀螺系统进行奇异性分析,分析表明该系统无内部奇异。提出一种剪式陀螺系统在陀螺同步条件下的伪逆操纵律。为提高同步性能和抗扰动能力,基于Lyapunov稳定性理论设计剪式陀螺系统的自适应非线性反馈控制器。仿真验证所设计的控制律和操纵律的有效性以及该陀螺系统驱动空间飞行器进行大角度姿态机动的能力。     

6 DOF synchronized control for spacecraft formation flying with input constraint and parameter uncertainties

This paper treats the problem of synchronized control of spacecraft formation flying (SFF) in the presence of input constraint and parameter uncertainties. More specifically, backstepping based robust control is first developed for the total 6 DOF dynamic model of SFF with parameter uncertainties, in which the model consists of relative translation and attitude rotation. Then this controller is redesigned to deal with the input constraint problem by incorporating a command filter such that the generated control could be implementable even under physical or operating constraints on the control input. The convergence of the proposed control algorithms is proved by the Lyapunov stability theorem. Compared with conventional methods, illustrative simulations of spacecraft formation flying are conducted to verify the effectiveness of the proposed approach to achieve the spacecraft track the desired attitude and position trajectories in a synchronized fashion even in the presence of uncertainties, external disturbances and control saturation constraint.     

航天产品环境工程技术的新进展--简介第47届美国IES年会的学术论文

评述了2001年美国"环境科学协会"年会有关航天产品环境试验工程的进展概况.重点介绍了实尺卫星或星箭合一声振、随机振动、分离冲击环境试验,试验规范与分析评估技术以及部件级试验与规范的进展情况.文中还涉及军转民方面的信息以及环境工程的最新进展.     

一种航天器一次母线故障在线检测定位方法

针对航天器电源系统中一次母线故障的在线检测定位问题,构建了一种基于扩展频谱时域反射法的高定位准确度在线检测方法。首先对该方法的定位误差进行了理论分析,通过提高检测系统采样频率,使定位误差达到±0.2 m以内,能够满足短距离一次母线的故障定位需求;在此基础上进一步分析了由于电源阻抗不匹配引起检测结果错误的问题,通过加入阻波器阻断了检测信号向电源端的传播路径,消除了电源阻抗不匹配的影响,保证了一次母线故障的正确检测。实验结果表明所采用的方法能够对一次母线断路和短路故障实现精确的在线检测定位。     

Vibration Control of Composite Spacecraft Booms Subjected to Solar Heating

In this paper, piezoelectric feedback control of vibration and instability of spacecraft booms modeled as circular thin-walled cross-section beams and subjected to solar radiant heating is investigated. Having in view that composite material systems are likely to play a great role in the design of these devices, the beam constituent materials encompass non-classical effects such as anisotropy and transverse shear. In addition, in order to induce beneficial elastic couplings, a special ply-angle distribution achieved via the usual helically wounding fiber-reinforced technology, the so called filament winding, is implemented. The dynamic governing equations including the temperature effects and the related boundary conditions are obtained via the application of Hamilton's principle. Toward the end of controlling the oscillations and prevent the occurrence of the thermal dynamic instability, a feedback control capability based on the use of the piezoelectric induced strain actuation is implemented. The performance of its implementation considered in conjunction with that of the structural tailoring are highlighted and pertinent conclusions are derived.     

网络控制系统及其在航天领域中的应用研究

网络控制系统作为新近出现并兴起的控制系统,其系统结构优秀,能够较好地满足航天器的自主性和智能性的要求,代表了航天器控制系统未来的发展趋势。从网络控制系统共性问题和航天领域专有问题进行了系统地分析,重点讨论航天器总线选用原则、可靠性及拓扑结构、总线负载、总线时延影响因素、通用仿真平台和网络消息调度等问题,并提出了相关的设计和实现方法。     

卫星的智能规划与调度

以对地观测卫星为例,分析卫星的结构功能和飞行任务的特点,并在此基础上建立卫星智能规划与调度系统。规划与调度系统由卫星模型和推理机组成,其中模型描述卫星结构功能和各种约束条件,推理机分析并解决这些约束条件,形成一个没有冲突的飞行计划。规划与调度系统还具有修正计划的能力,能满足任务删除、更改和新任务插入等需求。