基于学习观测器的航天器指定时间跟踪控制

针对一类含有外部扰动和执行器故障的刚体航天器姿态控制系统,提出一种基于自适应学习观测器的指定时间容错控制器的设计方案.首先,系统性地给出一种改进型自适应学习观测器设计方案,基于自适应学习观测器框架,设计航天器姿态系统的学习观测器实现对系统的综合扰动值估计;然后,利用综合扰动的估计信息和滑模控制理论设计指定时间容错跟踪控制器,使得系统的姿态角能够在指定时间跟踪指令信号,系统的收敛时间可通过容错控制器的参数预先设置,且与系统的初始状态值无关;接着,基于Lyapunov稳定性理论验证含有故障的姿态控制系统能够在指定时间内稳定;最后,通过数值仿真,与已有的观测器和有限时间控制方案进行对比,表明所提出方案的有效性和可行性.     

基于迭代学习观测器的航天器姿态主动容错控制

针对含有外部扰动和执行器故障的一类航天器姿态控制系统,本文提出基于迭代学习观测器的主动容错控制方案.首先,建立了含有外部扰动和执行器故障的航天器姿态控制系统的运动学和动力学模型.其次,为了提高观测器的故障估计精度,在传统迭代学习观测器设计基础上引入上一时刻状态估计误差信息,文章提出一种改进型学习估计算法.进一步,基于滑模控制和指定时间稳定理论,利用学习观测器的故障估计信息设计指定时间主动容错控制器.与现有的航天器主动容错控制方案相比,本文所提出的算法的优势在于可以使故障系统的姿态能在指定时间跟踪上指令信号.基于Lyapunov方法,本文从理论上证明了改进型学习观测器和姿态容错控制系统的稳定性.最后,通过数值仿真,说明了所提容错控制方案的有效性和可行性.     

航天器自适应快速非奇异终端滑模容错控制

针对存在外部干扰、转动惯量矩阵不确定以及执行器故障的航天器姿态跟踪控制问题,本文提出了基于自适应快速非奇异终端滑模的有限时间收敛故障容错控制方案.通过引入能够避免奇异点,且具有有限时间收敛特性的快速非奇异终端滑模面,设计了满足多约束条件有限时间收敛的姿态跟踪容错控制律,利用参数自适应方法使控制器不依赖转动惯量和外部干扰的上界信息.Lyapunov稳定性分析表明:在存在外部干扰、转动惯量矩阵不确定以及执行器故障等约束条件下,本文设计的控制律能够保证闭环系统的快速收敛性,而且对执行器故障具有良好的容错性能.数值仿真校验了该控制律在姿态跟踪控制中的优良性能.     

基于未知输入观测器的导弹间歇故障诊断

针对带有未知扰动和噪声的导弹间歇故障诊断问题,设计了一种基于未知输入观测器的导弹问题故障诊断方法,系统的输入部分或全部未知情况下也能获取系统状态的称为未知输入观测器.首先,为实现对外部扰动的解耦,设计降维未知输入观测器,并通过滑动时间窗口得到对间歇故障敏感而对未知扰动解耦的残差信号;然后,在满足误报率和漏报率的条件下,通过假设检验,确定了间歇故障发生时刻和消失时刻的可检测阈值;最后,对所提出的方法进行了仿真验证.仿真结果表明,在误差允许的范围内,设计的方法能够实现对间歇故障检测,满足实时性和准确性的要求.     

考虑输入饱和的近空间飞行器姿态容错控制

针对近空间飞行器姿态控制中出现的执行器故障,输入饱和与外部干扰等问题,设计了一种基于二阶滑模干扰观测器和辅助系统的鲁棒容错跟踪控制方法.首先,将系统不确定,外部扰动和执行器故障作为复合干扰,设计super-twisting二阶滑模干扰观测器对其进行估计.然后为解决输入饱和问题构造了辅助分析系统,并借助backstepping方法,设计姿态容错跟踪控制器.利用Lyapunov方法,严格证明了所有闭环系统信号的收敛性.最后将所设计的控制方法应用于近空间飞行器姿态控制中,仿真结果验证了该控制方法的有效性.     

基于积分滑模的航天器有限时间姿态容错控制

针对存在执行机构故障和外部干扰的刚体航天器姿态稳定系统,本文提出了基于积分滑模的容错控制策略,实现了姿态有限时间稳定.首先,利用齐次系统相关理论,设计了一类饱和有界的基础控制律,保证了不存在执行机构故障和干扰情况下的姿态有限时间稳定.在此基础上,利用积分滑模和自适应技术设计了一种有限时间姿态鲁棒容错控制方案,对执行机构故障和干扰进行有效的补偿;该方案能够快速地实现姿态高精度稳定,并抑制系统抖振现象.最后,将本文提出的姿态容错控制方案进行数值仿真与对比,验证了方案的有效性与优越性.     

一种基于时变干扰观测器的高超声速飞行器容错控制策略设计

为了提高高超声速再入飞行器(HRV)在执行机构故障情况下的姿态控制效果,提出一种基于时变干扰观测器和参考轨迹重构器(RVG)的滑模容错控制策略.首先,设计一种新型自适应干扰观测器(ADO)来估计系统扰动,在保证估计精度的同时,能够有效削弱传统干扰观测器的初始超调现象;然后,基于反步法设计HRV的滑模控制器,在设计中引入参考轨迹重构器以避免故障突变引起的初始尖峰,并且在滑模面的设计中利用ADO所估计的系统扰动实现干扰的在线补偿.仿真结果表明,所设计的控制策略可以有效解决传统的基于高增益干扰观测器的滑模控制律受故障引起的突变和初始估计误差造成控制系统动态性能恶化的问题.     

具有时变时滞的线性离散随机系统的间歇故障检测

针对一类具有时变时滞和外部未知扰动的线性离散随机系统,研究了其间歇故障检测问题.考虑一类具有周期性的时变时滞,利用提升技术和叠加原理将线性时变时滞系统转化为线性时不变系统.基于等价空间法设计对外部未知扰动解耦的结构化标量残差,在此基础上,通过残差统计特性分析和给定的显著性水平设定检测阈值.利用两个假设检验分别检测间歇故障的发生时刻和消失时刻,并分析了间歇故障的可诊断性.最后,仿真结果验证了该间歇故障检测方法的有效性.     

航天器执行机构部分失效故障的鲁棒容错控制

针对航天器在轨运行时受到外部干扰以及存在执行机构部分失效故障的问题,提出一种基于白适应滑模控制的鲁棒容错控制方法．该方法利用自适应算法估计执行机构故障的最小值,并通过设计滑模变结构控制器来实现对故障的容错控制以及对干扰的抑制控制,无需精确获得执行机构故障值,从而使得设计的控制器对于故障具有一定的鲁棒性．仿真结果表明了该...     

基于极点配置和椭球分析的传感器故障检测

针对具有未知扰动与测量噪声的线性离散时间系统,提出了一种传感器故障检测方法.首先,将传感器故障视为增广状态,将原始系统转化为一个等效的新线性动态系统.然后,基于鲁棒观测器设计和极点配置方法构造了一个故障检测观测器,使得生成的残差能够同时满足对扰动与噪声的鲁棒性和对故障的敏感性.此外,设计了一种基于椭球分析的残差评价方法,该方法可通过判断残差是否被无故障残差椭球包含来检测故障.最后,通过一个二阶RC电路模型的仿真算例验证了所提出方法的有效性与优越性.     

Adaptive diagnosis and compensation for hypersonic flight vehicle with multisensor faults

This study proposes an improved adaptive fault diagnosis and compensation scheme for multisensor faults of hypersonic flight vehicles (HFVs). The faults are detected and isolated through a series of sensor output residuals and thresholds that consider observation error and disturbances. Via an adaptive augmented observer, the faults are estimated accurately and a time‐varying disturbance is handled by an additional differential part. Sensor faults are compensated on the basis of estimation results, and disturbances are considered in the fault‐tolerant control (FTC) design, thereby improving the tracking accuracy of the altitude and velocity and robustness with respect to external disturbances for HFVs. The stability of diagnosis and FTC is analyzed by Lyapunov theory. Numerical simulation results explain the validity of the proposed diagnosis and compensation methods.     

一种基于最优未知输入观测器的故障诊断方法

针对含有未知输入干扰和噪音的不确定动态系统,使用全阶未知输入观测器(Unknown input observer, UIO)来消除干扰项,实现状态估计, 结合Kalman滤波器算法来求解状态反馈矩阵,以使得输出残差信号的协方差最小,从而增强系统对噪声的鲁棒性,实现了 一种基于最优未知输入观测器的残差产生器.采用极大似然比(Generalized likelihood ratio, GLR)的方法对残差信号进行评估,通过设定的阈值来提高诊断率. 最后以风力发电机组传动系统出现加性传感器故障和乘性传感器故障为例, 进行了残差信号的仿真,仿真结果说明了该方法的有效性.     

Observer-based fault tolerant control for a class of nonlinear multi-agent systems with sensor faults

This article focuses on the robust fault tolerant control (FTC) problem for a class of Lipschitz nonlinear multi-agent systems(MASs) subject to sensor faults. Firstly, sensor faults are transformed into actuator faults via introducing a new intermediate auxiliary state variable, and a distributed adaptive fault estimation observer is designed to estimate the state information and the concerned faults by using the relative output estimation error. Then, the sufficient existence conditions for the observer to satisfy the robust performance index are given. Thirdly, based on the results of observer design, a new design method of dynamic output feedback controller is proposed to implement consensus of MASs and ensure the desired disturbance rejection performance. Finally, the simulation results are presented to illustrate the effectiveness of the proposed method.     

An adaptive technique for robust diagnosis of faults with independent effects on system outputs

In this paper, Fault Detection and diagnosis (FDD) of faults with independent effect on system outputs by using the adaptive observer technique are investigated. At first, a class of linear systems without model uncertainty is considered. Then, a general situation where the system is subjected to either model errors or external disturbance is discussed. Robust adaptive control techniques are applied to guarantee convergence of certain signals to residual sets. An extension to FDD for a class of non-linear systems with non-linear fault function is extensively investigated. The novelty of this paper is that the strict positive realness (SPR) requirement on the plant transfer function in existing results is removed at the expense of requiring the existence of a positive definite solution to a certain matrix inequality. Furthermore, the problems of stabilization and robust stabilization by fault-tolerant control (FTC) and robust FTC are studied respectively, and faulttolerant controllers are designed to stabilize the close-loop systems. An aircraft example and a numerical example are included to verify the applicability of the proposed diagnosis methods.     

Prescribed-performance fault-tolerant control for feedback linearisable systems with an aircraft application

This paper investigates fault-tolerant control (FTC) for feedback linearisable systems (FLSs) and its application to an aircraft. To ensure desired transient and steady-state behaviours of the tracking error under actuator faults, the dynamic effect caused by the actuator failures on the error dynamics of a transformed model is analysed, and three control strategies are designed. The first FTC strategy is proposed as a robust controller, which relies on the explicit information about several parameters of the actuator faults. To eliminate the need for these parameters and the input chattering phenomenon, the robust control law is later combined with the adaptive technique to generate the adaptive FTC law. Next, the adaptive control law is further improved to achieve the prescribed performance under more severe input disturbance. Finally, the proposed control laws are applied to an air-breathing hypersonic vehicle (AHV) subject to actuator failures, which confirms the effectiveness of the proposed strategies.     

基于改进深度残差网络的GIS局部放电在线监测白噪声干扰抑制

针对GIS局部放电(partial discharge, PD)监测中背景白噪声较多、GIS局部放电信号干扰较大的问题,应用改进深度残差网络设计一种新的GIS局部放电在线监测白噪声干扰抑制方法。进行局部放电在线监测中白噪声、局部放电脉冲信号的多尺度特性分析,在局部放电脉冲染噪信号中提取白噪声信号。加入感知损失,设计由生成图像网络与损失网络构成的改进深度残差网络,对白噪声信号波形图像实施超分辨率重建。通过SN-EMD算法提取白噪声信号波形图像的模态域特征。通过构建复小波滤波器组,对模态域特征实施滤波处理,实现GIS局部放电在线监测中的白噪声干扰抑制。实验测试结果表明,设计方法去噪后的信噪比最高可达97.22 dB,干扰抑制前后信号的幅值相对误差最高可达63.20 dB,干扰抑制前后信号相关系数一直大于0.75,完成GIS局部放电在线监测白噪声干扰抑制。     

Fault accommodation for linear systems with time-varying delay

This paper studies the fault accommodation problem for linear systems with time-varying delay, system uncertainties and external disturbances. A novel intermediate estimator-based fault tolerant control (FTC) scheme is proposed, where an intermediate estimator is constructed to estimate the states and the faults simultaneously, based on the estimation; an FTC compensation scheme is designed to eliminate the effects of faults, system uncertainties and time-varying delay. It is proved that the states of the closed-loop system are uniformly ultimately bounded. A simulation example shows the effectiveness of the proposed method.     

Integrated fault estimation and fault‐tolerant control for uncertain Lipschitz nonlinear systems

This paper proposes an integrated fault estimation and fault‐tolerant control (FTC) design for Lipschitz non‐linear systems subject to uncertainty, disturbance, and actuator/sensor faults. A non‐linear unknown input observer without rank requirement is developed to estimate the system state and fault simultaneously, and based on these estimates an adaptive sliding mode FTC system is constructed. The observer and controller gains are obtained together via H_∞ optimization with a single‐step linear matrix inequality (LMI) formulation so as to achieve overall optimal FTC system design. A single‐link manipulator example is given to illustrate the effectiveness of the proposed approach. Copyright © 2016 John Wiley & Sons, Ltd.