【作者】 黎煊；

【导师】 吴晓蓓；

【作者基本信息】 南京理工大学 ， 控制科学与工程， 2009， 博士

【摘要】 本文研究了网络控制系统(networked control systems, NCSs)的故障检测与容错控制,主要内容如下：(1)研究了具有输出短时延和控制短时延的网络控制系统的故障检测与保成本容错控制问题。针对具有输出短时延和控制短时延的网络控制系统,假设系统传感器节点和控制器节点采用时间驱动,执行器节点采用事件驱动,将系统建模为具有参数不确定性的离散系统。首先考虑系统具有外在干扰情况下的故障检测问题,按照时延补偿策略设计了系统的鲁棒H∞故障观测器,利用Lyapunov方法和矩阵不等式方法,给出了观测器系统的稳定性条件,并对检测的鲁棒性和灵敏度进行了综合分析。接着考虑系统具有数据包丢失情况下的故障检测问题,设计了基于开环观测和闭环观测相结合的故障观测器,在数据包丢失率一定的情况下,将观测器误差系统等效为具有事件发生率约束的异步动态系统,基于异步动态系统理论和矩阵不等式方法,给出了系统的指数稳定性条件。然后基于观测器研究了具有输出短时延和控制短时延的网络控制系统传感器失效的完整性问题。按照时延补偿策略设计了系统的状态观测器。然后考虑可能发生的传感器故障,基于观测器建立了网络控制系统增广模型,针对二次型性能指标函数,利用控制器和观测器协同设计方法和矩阵不等式方法,得出了系统完整性条件,并给出了系统的保成本容错控制器和观测器的设计方法。(2)研究了长时延网络控制系统的故障检测与保成本容错控制问题。首先考虑具有输出长时延和数据包丢失的网络控制系统的故障检测问题,考虑执行器和传感器之间存在采样时钟异步的情况,建立了系统离散数学模型,根据控制器接收数据包的情况,设计了系统的故障观测器,并将观测器误差系统建模为一类具有不确定性的离散切换系统,基于切换系统理论和矩阵不等式方法给出了系统的稳定性条件。然后基于观测器,分别按照系统具有控制时延和同时具有控制时延和输出时延的情况,研究了长时延网络控制系统传感器失效的完整性问题。当系统具有控制时延时,设计了系统的状态观测器,当系统同时具有控制时延和输出时延时,设计了系统的时延补偿状态观测器,考虑可能发生的传感器故障,基于观测器分别建立了两种情况下的网络控制系统增广模型,针对二次型性能指标函数,利用控制器和观测器协同设计方法和矩阵不等式方法,分别得出了系统完整性条件,给出了系统的保成本容错控制器和观测器的设计方法。(3)研究了非线性网络控制系统的容错控制问题。针对被控对象可由Takagi-Sugeno(T-S)模糊模型描述的非线性网络控制系统,当网络诱导时延为时变不确定短时延时,将系统建模为一类具有参数不确定性的T-S模糊模型。在此基础上,设计了系统的模糊状态观测器,考虑到可能发生的传感器故障,利用模糊控制理论和矩阵不等式方法,得出了观测器系统在传感器故障时具有完整性的充分条件,并给出了模糊容错控制器和模糊观测器的设计方法。进一步地,研究了系统的H∞容错控制问题,给出了使系统满足扰动抑制性能指标的模糊容错控制器和模糊观测器设计方法。(4)研究了基于连续时间模型的变采样网络控制系统的容错控制问题。假设系统时变时延和采样间隔均有上界,利用混杂系统理论将系统建模为混杂系统。在此基础上考虑可能发生的执行器故障,应用Lyapunov稳定性理论和矩阵不等式方法,得出了保成本容错控制律的存在条件,给出了保成本容错控制器的设计方法和最小性能界的求解方法。然后考虑系统具有不确定性参数,研究了系统鲁棒容错控制器设计问题,给出了系统鲁棒容错控制器设计方法和系统完整性条件下最大时延估计值。进一步研究了系统的鲁棒H∞容错控制问题,给出了使系统满足扰动抑制性能指标的鲁棒容错控制器设计方法。更多还原

【Abstract】 The fault detection and fault-tolerant control for networked control systems (NCSs) are studied in this dissertation. The main researches are concluded as follows:(1) The fault detection and guaranteed fault-tolerant control for networked control systems with short output delay and short control delay are studied. Supposing that the sensor and controller nodes are time-driven and the actuator node is event-driven, the system is modeled as a discrete time system with parametrical uncertainties. Firstly, considering the system with disturbances, the problem of the fault detection is discussed. The robust H∞fault observer of the system is designed according to the time-delay compensation strategy. Then the stability condition of the observer system is given by using the approaches of Lyapunov and Matrix Inequalities, and the robustness and sensitivity are analyzed. Secondly, considering the system with data packet dropout, the problem of the fault detection is discussed. The fault observer composed of open-loop observation and close-loop observation is proposed. Under fixed packet dropout rate, the observer error system is equivalent to an asynchronous dynamical system and based on asynchronous dynamical system theory and the approach of Matrix Inequalities, the condition for exponential stability of the system is given. Thirdly, based on observer, the problem of integrity against sensor failures for the networked control systems with short output delay and short control delay is discussed. The state observer of the system according to the time-delay compensation strategy is designed. Then, considering possible sensor failures, an augmented mathematic model for the networked control systems based on observer is developed. In terms of the given quadratic performance index function, the integrity condition of the system is given and the designs for guaranteed cost fault-tolerant controller and observer are presented respectively by using the cooperative design approach of the controller and observer and the approach of Matrix Inequalities.(2) The fault detection and guaranteed fault-tolerant control for networked control systems with long time delay are studied. Firstly, the problem of the fault detection for the networked control systems with long output delay and data packets dropout is discussed. The discrete mathematical model is set up under the existence of asynchronous clock between the actuator and the sensor. Based on the model, the fault observer of the system is designed, according to conditions of data arrival of the controller, and the observer error system is equivalent to a discrete switched system with parametrical uncertainties. Then the stability condition of the system is given with the switched system theory and the approach of Matrix Inequalities. Secondly, based on observer, the problem of integrity against sensor failures is discussed supposing the networked control systems with control delay and both output delay and control delay, respectively. For the networked control systems with control delay, the state observe is designed and for the networked control systems with both output delay and control delay, the observer with delay compensation is constructed. Then according to possible sensor failures, an augmented mathematic model for the networked control systems based on state observer is developed respectively. In terms of the given quadratic performance index function, the integrity condition of the system is given and the designs for guaranteed cost fault-tolerant controller and observer are presented respectively, by using the cooperative design approach of the controller and observer and the approach of Matrix Inequalities.(3) The fault-tolerant control for nonlinear networked control systems is studied. The nonlinear networked control systems which plant can be described by T-S fuzzy models is modeled as a discrete time T-S fuzzy model when the network-induced delay is uncertain short time-varying delay. Then based on the model, the fuzzy state observer is designed and considering possible sensor failures, the sufficient stability condition of integrity against sensor failures is given and the designs for fuzzy fault-tolerant controller and fuzzy observer are presented by using the theory of fuzzy control and the approach of Matrix Inequalities. Then the H∞fault-tolerant control for the system is also studied and a fuzzy fault-tolerant controller and a fuzzy observer satisfying the H∞performance index are designed.(4) The fault-tolerant control for networked control systems under variable-period sampling based on the continuous-time model is studied. Assuming that the time-varying delay and the sampling instants have upper bound, the system is modeled as a hybrid system by employing hybrid system theory. Based on the model, considering the possible actuator failures, the existence conditions of guaranteed cost fault-tolerant control law is testified and the design for guaranteed cost fault-tolerant controller and the minimization guaranteed cost solution are presented in terms of the Lyapunov stability theory combined with Matrix Inequalities. Then, considering the system with parametrical uncertainties, the robust fault-tolerant controller method is studied. The robust fault-tolerant controller method and the maximum value of time-varying delays are given under the condition of the system with integrity. Furthermore, the robust H∞fault-tolerant controller method is also studied and a robust controller satisfying the H∞performance index is designed.更多还原