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.     

Design and simulation of fault diagnosis based on NUIO/LMI for satellite attitude control systems

This paper presents a scheme of fault diagnosis for flexible satellites during orbit maneuver. The main contribution of the paper is related to the design of the nonlinear input observer which can avoid false alarm arising from the disturbance from orbit control force. The effects of orbit control force on the fault diagnosis system for satellite attitude control systems, including the disturbing torque caused by the misalignments and the model uncertainty caused by the fuel consumed, are discussed, where standard Luenberger observer cannot work well. Then the nonlinear unknown input observer is proposed to decouple faults from disturbance. Besides, a linear matrix inequality approach is adopted to reduce the effect of nonlinear part and model uncertainties on the observer. The numerical and semi-physical simulation demonstrates the effectiveness of the proposed observer for the fault diagnosis system of the satellite during orbit maneuver.     

基于干扰观测器的导引头稳定平台滑模控制

针对导引头稳定平台存在不确定弹体速度干扰以及非线性摩擦干扰的问题,结合滑模控制和非线性干扰观测器理论,提出一种基于非线性干扰观测器的二阶滑模控制方法。针对系统模型中的多个不确定干扰项,首先,采用新型微分跟踪器对状态量的导数值进行估计,进而得到干扰项的估计值,通过坐标变换,将系统中的不确定项进行归一化处理,便于控制器设计;其次,基于新型微分跟踪器设计了新型非线性干扰观测器,以实现对归一化后系统干扰项的精确估计;最后,采用二阶滑模控制算法进行控制器设计。仿真实验证明,新型非线性干扰观测器精度高、响应快,基于干扰观测器的二阶滑模控制方法能够有效隔离弹体扰动与非线性摩擦对导引头稳定平台的干扰,提高了稳定平台的鲁棒性和跟踪精度。     

基于模糊干扰观测器的轨迹线性化控制研究

针对一类非线性不确定系统,基于轨迹线性化控制(TLC)方法及模糊干扰观测器(FDO)技术研究了一种新的非线性控制结构。利用模糊系统具有以任意精度逼近非线性函数的能力设计FDO对未知干扰和不确定进行估计,并通过鲁棒控制项来提高系统的性能。采用Lyapunov方法,证明了跟踪误差和干扰观测误差一致最终有界。最后利用提出的控制方案针对数值算例进行了仿真验证,仿真结果表明了控制方案的有效性和鲁棒性。     

基于观测器的一类不确定非线性系统自适应输出反馈控制

针对一类不确定非线性系统,基于非线性状态观测器采用回馈递推(Backstepping)设计方法提出了一种鲁棒自适应L2增益控制方案。该控制方案首先对系统的不可观测状态设计非线性状态观测器,在此基础上通过多步递推得到系统的控制律并设计了未知干扰的参数自适应律,使系统具有L2增益性能。同时把采用常规设计方法需要对过多参数进行辨识问题简化为只需对与未知干扰个数相同的参数进行辨识的问题,简化了控制器结构。最后通过仿真算例验证了所设计控制方案的有效性。     

Observer-based H∞ control over packet dropping networks

A new controller design problem of networked control systems with packet dropping is proposed. Depending on the place that the observer is put in the system, the network control systems with packet dropping are modeled as stochastic systems with the random variables satisfying the Bernoulli random binary distribution. The observer-based controller is designed to stabilize the networked system in the sense of mean square, and the prescribed H∞ disturbance attenuation level is achieved. The controller design problem is formulated as the feasibility of the convex optimization problem, which can be solved by a linear matrix inequality (LMI) approach. Numerical examples illustrate the effectiveness of the proposed methods.     

基于NDO的飞行模拟转台伺服系统跟踪控制

针对飞行模拟转台伺服系统跟踪控制问题,提出了一种基于非线性干扰观测器(nonlinear disturbance observer, NDO)的反推全局滑模控制方案。该方案利用NDO观测系统的参数不确定性及非线性摩擦干扰,通过选择适当的设计参数使观测误差指数收敛,进而对引入NDO的系统采用反推全局滑模设计控制器,控制律的设计保证了闭环系统的稳定性。仿真结果表明,所提控制方案能够有效克服参数不确定性及非线性摩擦干扰的影响,实现了转角位置的精确跟踪,并且有效去除了控制抖振。     

基于比例积分观测器的卫星姿控系统鲁棒故障重构

针对卫星在轨运行出现执行机构故障问题,提出了一种基于观测器的卫星姿控系统鲁棒故障重构方法。首先,考虑卫星出现空间干扰、测量干扰以及噪声,建立欧拉离散时间卫星姿控系统模型。其次,设计一种离散比例积分观测器(proportional integral observer, PIO)实现卫星姿态角和姿态角速度估计,并利用前一时刻的故障重构值和输出估计误差迭代更新当前故障重构信息。然后,采用干扰解耦思想设计离散PIO解耦部分空间干扰,并利用H_∞技术抑制剩余干扰和测量噪声的影响。另外,利用线性矩阵不等式工具箱求解了部分观测器增益矩阵。最后,仿真结果验证了所提故障重构方法的有效性。     

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.     

Design of Luenberger function observer with disturbance decoupling for matrix second-order linear systems-a parametric approach

1.INTRODUCTIONThere have been many approaches to disturbance de-couplinginlinear multivariable control systemdesign.Linnemann[1]proposed a numerically stable algorithmfor disturbance decoupling by measurement feedback.Van Der Woude[2]considered the combined problemof disturbance decoupling and stabilization by mea-surement feedback.Syrmos[3]proposed a numericallyefficient algorithm based on Sylvester equations forthe problemof disturbance decoupling with arbitrarypole placement usingstat…     

Actuator fault diagnosis of time-delay systems based on adaptive observer

1 .INTRODUCTIONOwingtotheincreasing demandfor highreliabilityinmany industrial processes , much attention has beenpaid to the problem of fault detection and diagnosis(FDD) in dynamic systems over the past twodecades. Fruitful results can be found in Refs .[1 ~3] .It is well known that faults in a dynamic systemcan take many forms . They can be actuator faults ,sensor faults ,unexpected abrupt changes of some pa-rameters or even unexpected structure changes[4 ,5].The purpose of detection…     

线性系统有限时间函数观测器设计的参数化方法

研究了线性系统有限时间函数观测器的参数化设计问题,其目的是通过设计参数化形式的函数观测器,使其在给定有限时间内能够直接估计关于线性系统状态的线性函数。基于一类Sylvester矩阵方程的参数化解,给出了该有限时间函数观测器所有增益矩阵的参数化表达式,其所含的自由参数为控制系统设计提供了全部的自由度,可通过适当选择这些自由参数使其满足某些系统性能指标。最后,数值例子及其仿真结果验证了所提线性系统有限时间函数观测器参数化设计方法的简单性和有效性。     

Observer-based H∞ control over packet dropping networks

A new controller design problem of networked control systems with packet dropping is proposed. Depending on the place that the observer is put in the system, the network control systems with packet dropping are modeled as stochastic systems with the random variables satisfying the Bernoulli random binary distribution. The observer-based controller is designed to stabilize the networked system in the sense of mean square, and the prescribed H∞ disturbance attenuation level is achieved. The controller design problem is formulated as the feasibility of the convex optimization problem, which can be solved by a linear matrix inequality （LMI） approach. Numerical examples illustrate the effectiveness of the proposed methods.     

非匹配不确定性条件下的编队分布式协同控制

针对非匹配不确定性、饱和输入等约束条件下的编队协同控制问题展开研究。通过引入辅助系统和扩张状态观测器实现对系统状态的实时跟踪;设计了滑模扰动观测器,实现在有限时间内精确估计系统的全部未知扰动;在此基础上,提出了反馈控制协议,显著改善了系统控制性能,有效降低了计算负担,使得通过选择合适参数能够保证状态追踪误差收敛到有界域内;最后通过Lyapunov稳定性理论对控制系统稳定性进行严格证明。数值算例验证了控制协议有效性,结果表明所设计的控制协议能够满足复杂约束条件下的编队协同控制要求。     

运载火箭的抗干扰分数阶控制器设计

针对火箭的姿态控制问题,基于自抗扰理论和分数阶控制,提出了一种控制器设计方法。通过设计扩张状态观测器,充分利用惯组平台和速率陀螺的复合量测信息对系统的内部和外部干扰进行估计。设计分数阶控制器对估计的干扰进行实时补偿,实现火箭的姿态控制,通过引入可调参数使得控制器参数调整范围变大,保证控制器具有更好的控制精度。考虑到控制器参数多且难以被确定,采用一种基于遗传算法和粒子群优化的混合算法对参数进行调整;通过仿真验证了所提算法可以获得良好的动态性能、抗扰性和鲁棒性。     

New trajectory linearization control for nonlinear systems undergoing harmonic disturbance

This paper presents a new trajectory linearization control scheme for a class of nonlinear systems subject to harmonic disturbance. It is supposed that the frequency of the disturbance is known, but the amplitude and the phase axe unknown. A disturbance observer dynamics is constructed to estimate the harmonic disturbance,and then the estimation is used to implement a compensation control law to cancel the disturbance. By Lyapunov's direct method, a rigorous pool shows that the composite error of the closed-loop system can approach zero exponen-tially. Finally, the proposed method is illustrated by the application to control of an inverted pendulum. Compared with two existing methods, the proposed method demonstrates better performance in tracking error and response time.     

一类化工过程自适应状态观测器的设计

提出了一种非线性系统自适应状态观测器的设计方法。根据系统工作点的变化在线配置极点,选取合适的反馈增益矩阵,无论如何选取状态观测器的初值,都能保证观测器在大范围内稳定工作。理论分析了存在模型误差和噪声干扰时观测器的鲁棒性。在CSTR上的仿真结果证明,用该方法设计的观测器能够稳定收敛到状态真值,并且对模型失配和噪声干扰有一定的抑制能力     

基于鲁棒故障诊断LPV模型的舰载QUAV跟踪控制

设计适用于外部干扰抑制的无人机鲁棒故障检测与跟踪控制系统。首先,将舰载四旋翼直升机(quad-roto unmanned aerial vehicle, QUAV)建模为线性变参数系统(linear variable parameter system, LPVs),作为目标来进行系统设计。同时,为了进行故障检测和隔离,设计了一个强大的LPVs观测器,利用一组可行线性矩阵不等式(linear matrix inequalities, LMI)给出保证系统渐近稳定和抗干扰鲁棒性的充分条件。此外,基于LMI区域的极点配置考虑观测器的增益设计。然后,通过观测器库考虑故障检测和隔离方案,检测和隔离传感器故障。其次,通过考虑比较器集成控制方案对反馈控制器进行设计。目标是设计鲁棒控制器,使QUAV无偏差跟踪设定位置。最后,通过在模拟模型中,对算法的有效性进行实验验证。     

基于非线性干扰观测器的高超声速飞行器反演滑模控制

针对高超声速飞行器非线性动力学系统中存在的高度非线性、多变量耦合及参数不确定等特点,利用非线性干扰观测器对各种干扰的逼近特性,结合反演滑模控制,设计了一种飞行器反演滑模控制器。该方法首先利用干扰观测器观测出系统的干扰,未观测出的部分干扰使用反演滑模控制进行补偿,避免了累积误差,实现对制导指令的鲁棒输出跟踪,并证明了系统稳定性。仿真结果验证了该方法能较理想地观测干扰,保证系统良好的鲁棒性。     

临近空间高超声速飞行器匹配化滑模姿态控制

针对临近空间高超声速飞行器非匹配不确定性姿态控制问题,提出一种新型匹配化滑模姿态控制系统设计方法。首先将含有非匹配不确定性的模型进行匹配化变换,得到匹配的不确定性模型。采用扩张干扰观测器估计不确定项,用来补偿系统输出量的微分。其次,基于干扰观测器及频域滤波器设计了一种渐近收敛的复合微分器,用来获取系统输出的一阶导数。在此基础上,采用变结构控制方法,提出了一种匹配化滑模姿态控制方法。最后,通过数字仿真验证了该方法的有效性,并与反步法进行了对比,对比结果表明本文的方法具有更好的快速性及鲁棒性。