基于模型的转台系统故障检测方法

研究了飞行模拟转台的建模与故障检测问题.飞行模拟转台不仅是导弹制导回路半实物仿真闭环系统中的一个环节,也是一个反馈控制系统,转台内部参数与仿真系统中的各种参数相互影响,导致故障传递特性复杂,无法简单的根据转台参数测试判断转台运行状态.根据转台系统的跟踪特性,提出了基于模型的转台系统故障检测方法.由于传统的转台建模方法存在建模困难、精度不高的问题,因此采用系统辨识方法,通过辨识实验的设计,借助Matlab软件系统辨识工具箱进行模型的辨识,建立了转台系统三个框架的数学模型,利用相同输入条件下的数学模型输出和实际系统输出之间的残差变化,对转台运行情况进行检测,较好的解决了转台系统的故障检测问题.通过对三种转台故障的检测,验证了改进方法的有效性.     

基于数据驱动残差评价策略的故障检测方法

提出一种基于残差评价策略的故障检测方法,在仅有系统残差数据的基础上,不依赖于系统解析模型进行故障检测,为基于数据驱动方法进行复杂系统的故障检测提供了新的理论依据.为了提高系统故障检测的准确性,在分析故障检测漏报率和误报率的基础上,对故障检测阈值进行优化设计,并通过对车辆电源系统可能发生的励磁系统故障进行故障检测,验证了所提出方法的准确性和有效性.     

基于T-S模糊神经网络模型的编码器故障软闭环容错控制方法

针对舞台吊杆调速系统中速度反馈元件增量式编码器可能产生的丢码、断码等问题,为防止故障影响的传播,结合数据驱动技术提出了一种基于T-S模糊神经网络(T-S FNN)模型的编码器故障检测与软闭环容错控制方法。首先,利用系统正常运行时的历史数据建立系统较为精确的T-S FNN预测模型,并用实际编码器测量值与模型预测值相减获得残差信息;其次,将其残差实时数据通过改进的序贯概率比检验(SPRT)算法进行故障检测,以克服检测延迟确保故障检测的可靠性,当检测出故障时,再用T-S FNN模型的预测输出替代故障编码器的输出,实现软闭环方式下的容错运行;最后,针对编码器丢码、断码等故障,采用上述方法进行了软闭环容错控制的有效性仿真验证。仿真结果表明,该方法能够快速可靠地检测到编码器故障,并用预测的重构信息通过容错切换机制,及时、安全地以软闭环方式实现了对故障编码器的容错控制,提高了舞台吊杆调速系统运行的安全可靠性。     

基于广义回归神经网络的传感器故障诊断研究

针对诊断传感器偏置故障与漂移故障的难点问题,提出了一种基于广义回归神经网络(GRNN)的传感器故障诊断方法。该方法充分利用控制系统闭环回路测控信息,建立一组多输入单输出GRNN观测器,通过将观测器输出与传感器实际输出相比较获取残差序列,获得基于残差序列的传感器偏置故障和漂移故障的辨识策略,实现控制系统传感器故障在线诊断。仿真结果表明:该方法可以快速准确地检测和分离传感器故障,辨识传感器故障类型、故障大小以及故障发生的时间。     

基于神经网络的无刷同步电机控制系统故障诊断研究

设计了一套无刷同步电机控制器的故障诊断系统,利用实际的非线性控制系统训练神经网络状态观测器,根据系统实际输出与神经网络观测器输出之间的残差来判别和检测实际控制系统的故障,针对系统控制器、电流和速度传感器故障进行故障诊断研究仿真实验。仿真结果表明该方法能有效抑制噪声,能快速准确地确定故障发生的时间、位置、大小以及故障的类型,具有很强的鲁棒性。说明该方法具有很强的适用性和应用价值。     

一种非线性系统被控对象故障诊断方法

控制系统中的传感器、执行器和被控对象的故障检测与诊断往往是把执行器和被控对象视为一个整体来研究, 这不利于故障的决策与处理. 对此, 设计了非线性系统故障诊断的滑模观测器, 提出一种诊断被控对象故障的方法, 即对非线性系统和执行器同时进行观测, 根据两观测器残差的变化情况判断出非线性系统中传感器、执行器和被控对象故障. 最后以单输入单输出非线性系统为例进行仿真, 验证了该方法的有效性.

     

基于输出反馈的鲁棒容错D-稳定性分析

研究线性不确定系统基于输出反馈的鲁棒容错控制问题.基于连续型执行器故障模式,利用线性矩阵不等式LMI,给出了系统基于输出反馈的鲁棒容错D-稳定的充分条件,并把控制器的设计方法归结为求解一族线性矩阵不等式组.与常规的方法相比,给出的控制器不仅保证闭环系统对执行器故障具有完整性,并且使闭环系统的极点配置在指定区域D中.通过仿真示例表明,无论执行器发生故障与否,得到的基于输出反馈的鲁棒容错控制器均保证闭环系统是D-稳定的,从而验证了所提出设计方法的有效性.     

抵御执行器故障的H∞静态输出反馈可靠控制

针对线性系统,考虑连续增益故障模型,研究了具有执行器故障的H∞静态输出反馈可靠控制问题。首先,在执行器无故障的前提下,给出H∞性能指标存在的充分条件,进而得出系统的静态输出反馈控制率。然后,基于执行器故障,重新设计静态输出反馈控制器,利用求解线性矩阵不等式的方法,完成静态输出反馈可靠控制器的设计。由此可靠控制器构成的闭环系统,使得当执行器发生故障时,也可使闭环系统的保持渐近稳定。最后的数值仿真验证了本文结果的有效性和可行性。     

线性时滞系统故障检测滤波器设计H∞优化方法

研究一类线性时滞系统的基于观测器的故障检测滤波器设计问题.通过对线性时滞系统进行广义坐标变换,得到了只包含输入、输出时滞,无状态时滞的新的系统表达形式.在此基础上,选用基于观测器的故障检测滤波器作为残差产生系统,使得到的残差动态方程为仅包含未知输入时滞和故障时滞的线性时不变形式,进而可应用已取得的线性时不变系统故障诊断研究成果设计故障检测滤波器.同时给出一种线性时滞系统故障检测滤波器设计的H∞优化设计方法,并通过算例验证了所提方法的有效性.     

基于扩展滤波器的非线性系统迭代学习故障诊断算法

针对一类存在执行器和传感器故障的非线性系统,提出基于滤波器的故障重构方法。为了使算法同时适用于状态和输出端,通过由系统方程构造新状态方程对系统作扩展变换,将原系统输出端非线性和故障转换到扩展系统的状态方程,在此基础上设计故障诊断滤波器,采用迭代学习调节算法更新虚拟故障使之逼近实际故障。该算法可以检测和估计系统故障,并且对不同类型故障具有一定的适应性。在单关节机器人模型上进行仿真实验,实验结果验证了所提出算法的可行性和有效性。     

Adaptive fault-tolerant control of nonlinear uncertain systems: an information-based diagnostic approach

This paper presents a unified methodology for detecting, isolating and accommodating faults in a class of nonlinear dynamic systems. A fault diagnosis component is used for fault detection and isolation. On the basis of the fault information obtained by the fault-diagnosis procedure, a fault-tolerant control component is designed to compensate for the effects of faults. In the presence of a fault, a nominal controller guarantees the boundedness of all the system signals until the fault is detected. Then the controller is reconfigured after fault detection and also after fault isolation, to improve the control performance by using the fault information generated by the diagnosis module. Under certain assumptions, the stability of the closed-loop system is rigorously investigated. It is shown that the system signals remain bounded and the output tracking error converges to a neighborhood of zero.     

Adaptive fault diagnosis and fault-tolerant control of MIMO nonlinear uncertain systems

This article presents an integrated fault diagnosis and fault-tolerant control (FTC) methodology for a class of nonlinear multi-input–multi-output systems. Based on the fault information obtained during the diagnostic procedure, an FTC component is designed to compensate for the effect of faults. In the presence of a fault, a baseline controller guarantees the boundedness of all the system signals until the fault is detected. After fault detection and then again after isolation, the controller is reconfigured to improve the tracking performance using online fault diagnostic information. Under certain assumptions, the stability and tracking performances of the closed-loop system are rigorously investigated. It is shown that the system signals always remain bounded and the output tracking error converges to a neighbourhood of the origin of the state space.     

Adaptive actuator fault compensation for linear systems with matching and unmatching uncertainties

The problem of process systems subject to actuator faults (partial loss of actuator effectiveness) is considered. An active fault compensation control law is designed that utilizes compensation in a way that accounts for matching and unmatching uncertainties and the occurrence of actuator faults. The main idea is designing the robust compensation controller to guarantee closed-loop stability in the presence of faults, based on a neural network representation of the fault dynamics. Changes in the system due to faults are modeled as unknown nonlinear functions. The updating control law is derived such that all the parameters of the closed-loop system are bounded. An output feedback controller is used to the “healthy” system and the adaptive feedback controller is used to compensate for the effect of the dynamics caused by the fault. The advantage of fault compensation is the dynamics caused by faults can be accommodated online. The proposed design method is illustrated on a three-tank system.     

Simultaneous fault detection and control for switched systems with actuator faults

This paper is concerned with the fault detection and control problem for discrete-time switched systems. The actuator faults, especially ‘outage cases’, are considered. The detector/controller is designed simultaneously such that the closed-loop system switches under an average dwell time, and when a fault is detected, an alarm is generated and then the controller is switched to allow the norm of the states of the subsystem to increase within the acceptable limits. Thus, a switching strategy which combines average dwell time switching with event-driven switching is proposed. Under this switching strategy, the attention is focused on designing the detector/controller such that estimation errors between residual signals and faults are minimised for the fulfillment of fault detection objectives; simultaneously, the closed-loop system becomes asymptotically stable for the fulfillment of control objectives. A two-step procedure is adopted to obtain the solutions through satisfying a set of linear matrix inequalities. An example comprising of three cases is considered. Through these cases, it is demonstrated that the fault detection and control for switched systems using a two-stage switching strategy and asynchronous switching are feasible.     

Fault detection for output feedback control systems with actuator stuck faults: A steady‐state‐based approach

The paper studies the fault detection problem for output feedback control systems with bounded disturbances and nonzero constant reference inputs. A steady‐state‐based approach is proposed which can be used to detect small actuator stuck faults including actuator outage (the stuck value is zero). These small stuck faults, especially the outage faults, cannot be detected effectively using the existing techniques. A dynamic output feedback controller and a weighting matrix are designed simultaneously. The dynamic output feedback controller stabilizes the closed‐loop system for both fault‐free and faulty cases and attenuates the effects of disturbances. By manipulating the steady‐state values of system states with the detection weighting matrix, a residual is then generated, through which actuator stuck faults including actuator outages can be detected effectively. Simulation results are included to demonstrate our design procedure. Copyright © 2009 John Wiley & Sons, Ltd.     

基于神经网络的非线性观测器及在线故障检测

提出一种基于径向基函数神经网络的非线性观测器的设计方法，并将其应用于复杂非线性系统的故障检测与隔离。该方法将神经网络离线学习与在线学习相结合，获取系统输入输出的非线性动力学特性，进而实时计算出残差并进行逻辑判决，可显著提高故障检测的快速性、鲁棒性及准确率。最后，针对非线性同步交流电机的结构损伤故障进行了仿真，结果表明本文所提方法的有效性。     

Fault-tolerant cooperative output regulation for multi-vehicle systems with sensor faults

This paper presents a unified framework of fault diagnosis and fault-tolerant cooperative output regulation (FTCOR) for a linear discrete-time multi-vehicle system with sensor faults. The FTCOR control law is designed through three steps. A cooperative output regulation (COR) controller is designed based on the internal mode principle when there are no sensor faults. A sufficient condition on the existence of the COR controller is given based on the discrete-time algebraic Riccati equation (DARE). Then, a decentralised fault diagnosis scheme is designed to cope with sensor faults occurring in followers. A residual generator is developed to detect sensor faults of each follower, and a bank of fault-matching estimators are proposed to isolate and estimate sensor faults of each follower. Unlike the current distributed fault diagnosis for multi-vehicle systems, the presented decentralised fault diagnosis scheme in each vehicle reduces the communication and computation load by only using the information of the vehicle. By combing the sensor fault estimation and the COR control law, an FTCOR controller is proposed. Finally, the simulation results demonstrate the effectiveness of the FTCOR controller.     

一种基于小波神经网络故障检测方法的仿真研究

文中提出了一种基于小波神经网络一性观测器的故障检测方法。它是一种把信号分析和模型相结合的故障检测方法,通过小波对信号的去噪和神经的神经网络的自学习功能,来获取系统输入输出的非线性动力学特性,进而实时计算出残差并进行逻辑判疡,可提高故障检测的速度和准确率。对同步交流电机的结构损伤故障进行了仿真,结果表明了该方法是可行的。     

Fault Accommodation for a Class of Nonlinear Uncertain Systems With Event-Triggered Input

The event-triggered fault accommodation problem for a class of nonlinear uncertain systems is considered in this paper.The control signal transmission from the controller to the system is determined by an event-triggering scheme with relative and constant triggering thresholds.Considering the event-induced control input error and system fault threat,a novel eventtriggered active fault accommodation scheme is designed,which consists of an event-triggered nominal controller for the time period before detecting the occurrence of faults and an adaptive approximation based event-triggered fault accommodation scheme for handling the unknown faults after detecting the occurrence of faults.The closed-loop stability and inter-event time of the proposed fault accommodation scheme are rigorously analyzed.Special cases for the fault accommodation design under constant triggering threshold are also derived.An example is employed to illustrate the effectiveness of the proposed fault accommodation scheme.