不确定广义系统的观测器设计

针对含仿射型不确定广义系统状态的观测器设计问题,利用不确定广义系统的已知信息通过插值法为不确定广义系统设计一个奇异全阶观测器,而且此观测器是仿射二次稳定的。观测器的状态和增益矩阵通过参数的线性插值得到,估计误差通过仿射参数独立的Lyapunov函数确定,且系统重构误差是仿射二次稳定的。给出数值仿真算例验证该算法的有效性。     

Robust iterative learning control for nonlinear systems with measurement disturbances

The iterative learning control (ILC) has been demon-strated to be capable of considerably improving the tracking perfor-mance of systems which are affected by the iteration-independent disturbance. However, the achievable performance is greatly degraded when iteration-dependent, stochastic disturbances are pre-sented. This paper considers the robustness of the ILC algorithm for the nonlinear system in presence of stochastic measurement disturbances. The robust convergence of the P-type ILC algorithm is firstly addressed, and then an improved ILC algorithm with a decreasing gain is proposed. Theoretical analyses show that the proposed algorithm can guarantee that the tracking error of the nonlinear system tends to zero in presence of measurement dis-turbances. The analysis is also supported by a numerical example.     

Robust fault diagnosis with disturbance rejection and attenuation for systems with multiple disturbances

The fault diagnosis problem is investigated for a class of nonlinear neutral systems with multiple disturbances.Time-varying faults are considered and multiple disturbances are supposed to include the unknown disturbance modeled by an exo-system and norm bounded uncertain disturbance.A nonlinear disturbance observer is designed to estimate the modeled disturbance.Then,the fault diagnosis observer is constructed by integrating disturbance observer with disturbance attenuation and rejection performances.The augmented Lyapunov functional approach,which involves the tuning parameter and slack variable,is applied to make the solution of inequality more flexible.Finally,applications for a two-link robotic manipulator system are given to show the efficiency of the proposed approach.     

基于迭代学习-未知输入观测器的卫星姿控系统鲁棒故障重构

针对卫星姿控系统出现执行机构故障,提出一种基于迭代学习-未知输入观测器(iterative learning unknown input observer, IL-UIO)的鲁棒故障重构方法。首先,考虑卫星出现空间干扰力矩、模型不确定性以及陀螺漂移,建立小角度机动时的非线性姿控系统模型。其次,采用UIO干扰解耦原理和H_∞控制思想,设计IL-UIO估计卫星姿态欧拉角和角速度的同时,利用IL算法实现执行机构鲁棒故障重构。并利用Lyapunov稳定性理论证明了IL-UIO稳定性和动态故障偏差最终有界, 通过线性矩阵不等式(linear matrix inequaliry, LMI)工具箱求解了观测器部分参数矩阵。最后,建立卫星闭环姿控系统并进行仿真,仿真结果验证了此方法的有效性。     

一类参数不确定非线性系统的故障检测与重构

飞行器在全包络上表现出明显的气动参数不确定性,以某无人机纵向模型为研究对象,提出一种不确定参数在线估计的自适应观测器故障重构方法。首先,将系统状态方程描述为一类带时变参数的仿射非线性结构,在参数增广系统能观性分析基础上,采用增广容积卡尔曼滤波(augmented cubature Kalman filter, ACKF)算法实现气动参数在线估计,以克服鲁棒性死区故障检测方法的保守性,提高检测灵敏度。其次,将所估计参数用于自适应观测器设计,由于Lie导数分析方法保证了对象系统的能观性,故系统不必满足文献方法中的特定规范形式;在此基础上,给出了故障检测自适应阈值和故障参数调节律,并分析了估计误差的收敛性。仿真实验表明了所提方法的有效性。     

Fault detection for nonlinear networked control systems based on fuzzy observer

Security and reliability must be focused on control systems firstly, and fault detection and diagnosis (FDD) is the main theory and technology. Now, there are many positive results in FDD for linear networked control systems (LNCSs), but nonlinear networked control systems (NNCSs) are less involved. Based on the T-S fuzzy-modeling theory, NNCSs are modeled and network random time-delays are changed into the unknown bounded uncertain part without changing its structure. Then a fuzzy state observer is designed and an observer-based fault detection approach for an NNCS is presented. The main results are given and the relative theories are proved in detail. Finally, some simulation results are given and demonstrate the proposed method is effective.     

Optimal tracking control for linear time-delay large-scale systems with persistent disturbances

An optimal tracking control (OTC) problem for linear time-delay large-scale systems affected by external persistent disturbances is investigated. Based on the internal model principle, a disturbance compensator is constructed. The system with persistent disturbances is transformed into an augmented system without persistent disturbances. The original OTC problem of linear time-delay system is transformed into a sequence of linear twopoint boundary value (TPBV) problems by introducing a sensitivity parameter and expanding Maclaurin series around it. By solving an OTC law of the augmented system, the OTC law of the original system is obtained. A numerical simulation is provided to illustrate the effectiveness of the proposed method.     

弹载伺服系统中输出多采样率扰动观测器应用

基于输出多采样率反馈理论与时滞估计原理,提出一种输出多采样率扰动观测器,给出了推导过程及稳定条件。与传统的时滞扰动观测器相比,所提出的扰动观测器利用系统的快速采样输出来估计扰动量,具有滞后量小、结构简单、易于实现等优点。将所提出的扰动观测器应用于导引头伺服控制系统中,仿真结果表明:输出多采样率扰动观测器对弹体耦合干扰力矩、摩擦力矩等外部扰动力矩具有较高的补偿精度,能够有效提高导引头伺服系统的控制精度。     

基于不确定理论的退化数据分析方法

作为可靠性领域传统的数学工具,概率论难以解决现代可靠性工程面临的难题。本文以不确定理论在退化数据分析中的应用为切入点,阐述了不确定理论的基本公理、运算法则与不确定统计方法,给出了基于确信可靠性理论的可靠性建模思路,提出了不确定失效阈值情形下的退化数据分析与可靠性建模方法。利用时变不确定正态分布建立产品的退化方程,根据专家知识建立失效阈值的不确定分布进而构建裕量方程,最终根据度量方程推导出产品可靠性模型。使用不确定统计中的极大似然估计法与假设检验法解决参数估计与模型验证问题。案例分析说明如果不考虑失效阈值的不确定性,会造成可靠性评估结果较大偏差。研究表明不确定理论适合处理退化数据分析中的不确定性难题,具有广阔的应用前景。     

Observer design for matrix second order linear systems with uncertain disturbance input-a parametric approach

1. INTRODUCTION Matrix second-order linear (MSOL) systems capture the dynamic behavior of many natural phenomena and have wide applications in several fields, such as vibration and structural analysis, spacecraft control and robotics control thus, they have attracted consider- able attention[1~10]. In Ref. [3], the controllability and observability theory of MSOL systems was studied directly in the matrix second-order framework. One type of observers for MSOL systems was proposed in …     

Feedforward and feedback optimal control for linear time-varying systems with persistent disturbances

1 .INTRODUCTIONIn nature ,there are various external disturbancesaffecting the performances of systems . Many con-trol problemsinvolve designing a controller capableof stabilizing a given linear system while mini mi-zing the worst-case response to some additive dis-turbances . This problemis relevant to disturbancerejection and cancellation. One application area ofinterest is flight control through wind shear ,where disturbances arise from a modal for windshear based on harmonic oscillati…     

一类不确定时延网络控制系统的故障诊断

研究了具有不确定时延的网络控制系统的故障诊断问题。通过建模将一类具有不确定时延的网络控制系统等效为具有不确定性的离散线性系统,并构建了故障观测器对系统进行故障检测。基于线性矩阵不等式(LMI)的方法,将故障诊断问题转化为系统鲁棒性的设计问题,给出并证明了解存在的条件以及观测器增益矩阵的求解方法。最后通过仿真验证了该算法的有效性。     

Disturbance observer based time-varying sliding mode control for uncertain mechanical system

It is now well known that the time-varying sliding mode control (TVSMC) is characterized by its global robustness against matched model uncertainties and disturbances. The accurate tracking problem of the mechanical system in the presence of the parametric uncertainty and external disturbance is addressed in the TVSMC framework. Firstly, an exponential TVSMC algorithm is designed and the main features are analyzed. Especially, the control parameter is obtained by solving an optimal problem. Subsequently, the global chattering problem in TVSMC is considered. To reduce the static error resulting from the continuous TVSMC algorithm, a disturbance observer based time-varying sliding mode control (DOTVSMC) algorithm is presented. The detailed design principle and the stability of the closed-loop system under the composite controller are provided. Simulation results verify the effectiveness of the proposed algorithm.     

Fault detection observer design for networked control system with long time-delays and data packet dropout

Focusing on the networked control system with long time-delays and data packet dropout, the problem of observerbased fault detection of the system is studied. According to conditions of data arrival of the controller, the state observers of the system are designed to detect faults when they occur in the system. When the system is normal, the observers system is modeled as an uncertain switched system. Based on the model, stability condition of the whole system is given. When conditions are satisfied, the system is asymptotically stable. When a fault occurs, the observers residual can change rapidly to detect the fault. A numerical example shows the effectiveness of the proposed method.     

连续广义系统的未知输入观测器研究

研究了在未知输入下连续广义系统的降阶观测器的设计方法,并讨论了观测器在故障检测中的应用。首先给出了连续估计器的存在条件,通过给原系统加微分反馈实现正则化,又通过解耦变换使得只有一个状态向量含有未知输入,利用其余两个不受未知输入影响的状态向量设计出观测器。然后,假设未知输入为故障信号的情况下,利用观测器的方法研究了连续广义系统的故障检测问题。仿真结果显示了满意的估计性能。     

具有异步时延的网络化控制系统故障检测

针对具有异步信号时延的离散系统，研究了在异步时延下基于观测器的故障检测及其设计问题。首先提出了一个存在异步时延下系统的故障检测模型，该模型保持了系统的定常性和时不主特性。同时在此模型上构造了异步时延系统的状态观测器，并依据系统观测误差通过合理地选择湮灭加权矩阵的方法构建了频域内的故障检测残差发生器。最后通过一个摆式列车试验模型的仿真检验了设计方法的有效性。     

Fault detection filter design for linear discrete time-varying systems with multiplicative noise

The problem of fault detection for linear discrete timevarying systems with multiplicative noise is dealt with.By using an observer-based robust fault detection filter(FDF) as a residual generator,the design of the FDF is formulated in the framework of H ∞ filtering for a class of stochastic time-varying systems.A sufficient condition for the existence of the FDF is derived in terms of a Riccati equation.The determination of the parameter matrices of the filter is converted into a quadratic optimization problem,and an analytical solution of the parameter matrices is obtained by solving the Riccati equation.Numerical examples are given to illustrate the effectiveness of the proposed method.     

测量时滞系统的故障诊断和动态自修复控制

研究含有测量时滞的线性系统的故障诊断和自修复控制问题.提出了一种测量时滞系统基于降维状态观测器的故障诊断方法.通过构造含有故障状态的增广系统并进行增广系统测量时滞的无时滞转换,将测量时滞系统的故障诊断问题转化为无时滞增广系统的状态观测问题.通过构造增广系统的降维状态观测器,设计了在线诊断故障的故障诊断器.利用故障诊断的结果,设计了故障的动态自修复控制律使系统在故障情况下能够正常运行.最后,通过一个仿真算例来验证本文所提出的方法的可行性和有效性.