基于干扰特性指标与推力分配的载人潜水器容错控制

载人潜水器在深海复杂恶劣的环境中运行, 容易受到外部环境干扰和推进器故障的困扰, 本文将干扰特性指标与基于推力分配的主动容错控制方法相结合, 提出了一种新的主动容错控制方法. 首先, 建立了载人潜水器系统的数学模型; 其次, 设计非线性干扰观测器估计系统所受的集总干扰, 并设计无推进器故障时的控制器; 然后, 针对推进器故障问题, 引入权重矩阵进行推力分配以保护故障推进器, 并设计了干扰特性指标表示干扰的性质对跟踪误差和推力损失的影响; 在此基础上, 给出了一种基于干扰特性指标与推力分配的新型容错控制方法, 李雅普诺夫方法保证了该控制算法的理论稳定性; 最后, 通过数值仿真, 验证所设计的控制方法的优越性. 其优越性主要体现在: 能够利用可用干扰与补偿有害干扰, 并将可用的干扰能量用于补偿故障推进器的推力缺失.     

存在部分解耦扰动的网络化系统容错控制

针对一类存在执行器故障和部分解耦扰动的离散时间网络化控制系统,研究测量数据随机丢失情况下的主动容错控制问题。首先,通过模型转换将原系统化为一个与之等价的状态增广系统;然后在考虑测量数据发生随机丢失情况下,构造未知输入观测器(unknown input observer, UIO)实现对系统状态与故障的联合估计,再基于状态和故障的在线估计值,设计基于信号补偿的容错控制律实现对原系统的主动容错控制。在该容错控制算法中,观测器与控制器增益的存在性条件均可利用李雅普诺夫稳定性理论对误差系统进行随机分析得到,相应的估计器和控制器参数可通过在线求解具有凸约束的矩阵不等式获得。最后,通过一个喷气式发动机模型的仿真算例验证所提出的故障估计与主动容错控制方法的有效性。     

离散时间系统的主动容错控制及飞控应用

针对处理一类线性不确定离散时间系统多重的、同时发生的、突变的舵机故障问题,提出了一种新的故障估计方案。该方案考虑了两种舵机故障模型:舵机卡死和舵机失效。所提出的舵机故障估计方案适用于为战机设计一个H∞容错飞行控制器,用于以零横向加速度跟踪飞机转弯角和俯仰率指令。仿真结果表明,采用H∞容错飞行控制器能够取得较好的控制效果。     

雕刻机系统数据驱动建模与容错跟踪控制

通过分析在速度控制运行模式的雕刻机系统输入角速度与输出位置之间的机理关系,将其系统利用一个积分因子和一个稳定传递函数相连接的模型进行模拟.通过引入微分滤波器对采样数据进行处理,将难以辨识的临界不稳定积分模型转换成易于辨识的稳定模型.提出一种能够精确估计带积分因子的递推最小二乘算法,并采用辅助变量法消除因滤波引起的有色噪声的影响.所提出算法可以确保在开环状态下对积分系统进行精确估计.针对多轴雕刻机运动控制系统,提出一种基于中间观测器的容错跟踪控制算法.针对与输入通道匹配的过程故障,设计基于故障估计值的容错控制反馈率以进行有效补偿;对于不匹配故障,通过调节中间观测器增益实现充分抑制.最后,通过与现有算法进行对比实验,验证了所提出算法的可行性和优越性.     

Simultaneous fault estimation and fault-tolerant tracking control for uncertain nonlinear discrete-time systems

This paper deals with simultaneous fault estimation and control for a class of nonlinear systems with parameter uncertainty, which is described by Takagi–Sugeno (T–S) fuzzy model with parameter uncertainties and unknown disturbance. In this paper, a fuzzy reference model is used to generate error dynamic for tracking control. By considering actuator fault as an auxiliary state vector, we construct an augmented error system and propose a fault estimator/controller to achieve simultaneous fault estimation and fault-tolerant tracking control. H_∞ approach is used in the design of estimator/controller to attenuate the effect of the unknown disturbance and parameter uncertainties. The design conditions are formulated into a set of linear matrix inequalities (LMIs), which can be efficiently solved. Finally, a pitch-axis nonlinear missile model is used to illustrate the effectiveness of the proposed method.     

Fault tolerant sliding mode control for T-S fuzzy stochastic time-delay system via a novel sliding mode observer approach

In this paper, a fault estimation and fault-tolerant control problem for a class of T-S fuzzy stochastic time-delay systems with actuator and sensor faults is investigated. A novel sliding mode observer is proposed, which can simultaneously estimate the system states, actuator and sensor faults with good accuracy. Based on the state and actuator fault estimation, a new sliding mode control scheme is developed, which can effectively eliminate the influence of actuator fault. Sufficient conditions for the existence of the proposed observer and fault-tolerant sliding mode controller are provided in terms of linear matrix inequality, and moreover, the reachability of the sliding mode surface can be guaranteed under the proposed control scheme. The propose sliding mode observer and fault-tolerant sliding mode controller can overcome the restrictive assumption that the input matrix of all local modes is the same. Finally, a numerical example is provided to verify the effectiveness of the proposed sliding mode observer and fault-tolerant sliding mode control technique.     

执行器故障多率采样间歇过程的鲁棒 耗散迭代学习容错控制

针对一类具有干扰和执行器故障的多率采样间歇过程,提出一种具有鲁棒耗散性能的迭代学习容错控制算法.通过提升技术将多采样率过程用慢速率采样的状态空间模型来描述,并基于二维系统理论,把迭代学习控制过程转化为等价2D Roesser故障系统,再沿时间和迭代方向设计具有耗散性能的反馈容错控制器,并以线性矩阵不等式形式给出容错控制器存在的充分条件,同时确保多率采样间歇过程在正常和故障条件下的耗散性能.注塑过程的注射速度控制仿真验证了方法的有效性和可行性.     

Fault estimation and active fault-tolerant control for a class of nonlinear systems with actuator and sensor faults based on unknown input iterative learning

In this paper, fault estimation and active fault-tolerant control are studied for a class of nonlinear systems with simultaneous actuator and sensor faults, as well as unknown external disturbances. Firstly, the state equation of a class of nonlinear systems is transformed into an augmented system state equation by extending the sensor fault as an auxiliary state. Then, a novel fault estimation observer based on iterative learning with unknown inputs is designed to estimate the system state, as well as actuator and sensor faults. Subsequently, by using the fault estimation information, a dynamic output feedback active fault-tolerant control scheme is proposed to compensate for the influence of faults on the system. Lyapunov stability theory is used to prove the stability of the closed-loop system and the convergence of the fault estimation observer. The gain matrices of the fault estimation observer and fault-tolerant controller are obtained by solving linear matrix inequalities. Furthermore, the paper avoids the use of the $$ norm in the convergence proof of the conventional iterative learning algorithm, which reduces the amount of calculation in the derivation process. Finally, the effectiveness and accuracy of the proposed method are verified through simulation of the DC motor angular velocity system.     

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.     

Observer-based fuzzy adaptive fault control for a class of MIMO nonlinear systems

In this paper, the fault-tolerant control (FTC) problem is investigated for a class of multi-input multiple output nonlinear systems with time-varying delays, and an active FTC method is proposed. The controlled system contains unknown nonlinear functions, unknown control gain functions and actuator faults, which integrates time-varying bias and gain faults. Then, fuzzy logic systems are used to approximate the unknown nonlinear functions and unknown control gain functions, fuzzy adaptive observers are used for fault detection and isolation. Further, based on the obtained information, an accommodation method is proposed for compensating the actuator faults. It is shown that all the variables of the closed-loop system are semi-globally uniformly bounded, the tracking error converges to an arbitrary small neighbourhood of the origin. A simulation is given to demonstrate the effectiveness of the proposed approach.     

约束多传感器线性系统的RMPC容错控制

针对一类约束多传感器线性故障系统,提出了一种基于鲁棒预测控制策略的容错控制方案．首先为多传感器线性系统设计了观测器,然后离线设计不变集列,使得时变的状态估计误差存在于相应的不变集列中,利用不变集的理论提出了一种新的故障检测的方法,最后基于鲁棒预测控制策略为故障系统设计了容错控制器,给出了闭环系统鲁棒稳定性的证明．仿真结果证明了方法的可行性。     

基于动态事件触发的混沌系统故障容错同步问题

针对混沌系统故障容错同步问题进行研究,设计基于动态事件触发的同步控制器以实现混沌系统的故障容错同步.首先,针对系统中存在的故障环节构造故障容错的系统模型,在此基础上采用输入-状态稳定性(ISS)的方法,将控制器求解问题转化为求解所对应故障容错系统的稳定性问题;然后,通过构造Lyapunov函数给出混沌系统故障容错同步的充分条件,通过引入动态变量,使得所设计的触发条件可以根据系统的运行状态进行动态调整,在实现系统故障容错同步的同时,最大程度地降低网络的占用率;最后,通过数值仿真验证所提出方法的有效性.     

考虑传感器故障的导弹姿态控制系统主动容错控制研究

针对导弹姿态控制系统惯性传感器故障,提出了基于信号重构的主动容错控制方法.分别利用基于梯形算法的数值积分器和有限时间收敛微分器对姿态角信号和角速率信号进行重构,当在线诊断出姿态角或角速率传感器故障时,以重构信号代替故障信号进行反馈控制来实现系统的主动容错控制.在建立导弹姿态控制系统模型并采用次最优控制方法设计输出反馈控制器的基础上,对所设计的主动容错控制方法进行仿真,仿真结果表明该方法是有效的.     

Intelligent fault-tolerant system of vibration control for flexible structures

This paper describes an intelligent fault-tolerant control method for vibration control of flexible structures. We consider a case where the fault phenomena of the control system for flexible structures can be treated as a change of system parameters. Therefore, the adaptive control method can be applied to a vibration control system for flexible structures with a fault. In this paper, a neural network (NN) adaptive control system is used to compensate for the change in the parameters of a plant with a fault. When the characteristics of the plant and of a nominal model have been agreed by a NN adaptive control system, the control method designed for the nominal model, such as decoupling feedback control or linearizing feedback control, can be used even if the change in the system parameters has been caused by a fault. To confirm the effectiveness of the proposed fault-tolerant control method, the simulational results from a 5-link robotic arm are shown at the end of the paper. This work was presented, in part, at the Fourth International Symposium on Artificial Life and Robotics, Oita, Japan, January 19–22, 1999     

Adaptive fault-tolerant control of linear systems with actuator saturation and L2-disturbances

This paper studies the problem of designing adaptive fault-tolerant H-infinity controllers for linear timeinvariant systems with actuator saturation. The disturbance tolerance ability of the closed-loop system is measured by an optimal index. The notion of an adaptive H-infinity performance index is proposed to describe the disturbance attenuation performances of closed-loop systems. New methods for designing indirect adaptive fault-tolerant controllers via state feedback are presented for actuator fault compensations. Based on the on-line estimation of eventual faults, the adaptive fault-tolerant controller parameters are updated automatically to compensate for the fault effects on systems. The designs are developed in the framework of the linear matrix inequality （LMI） approach, which can guarantee the disturbance tolerance ability and adaptive H-infinity performances of closed-loop systems in the cases of actuator saturation and actuator failures. An example is given to illustrate the efficiency of the design method.     

Fault-tolerant control systems design via subdivision of parameter region

This paper presents a linear matrix inequality （LMI） approach to solve the fault-tolerant control （FTC） problem of actuator faults. The range of actuator faults is considered as a parameter region and subdivided into several subregions to achieve a certain desired performance specification. Based on the integral quadratic constraint （IQC） approach, a passive fault-tolerant controller for the whole fault region and multiple fault-tolerant controllers for each fault subregion are designed for guaranteeing stability and improving performance of the FTC system, respectively. According to the estimation of parameters by FDI process, the corresponding subregion controller is chosen for the stability and optimal performance of closed-loop systems when the fault occurs. The case of incorrect estimation is also considered by comparing the performance index between the switched controller and the passive fault-tolerant controller. The proposed design technique is finally evaluated in the light of a simulation example.     

A fault-tolerant control strategy for non-linear discrete-time systems: application to the twin-rotor system

In this paper, an active fault-tolerant control scheme is proposed in the case of actuator faults. In particular, the general idea of integrating fault identification and control schemes, which takes into account the fault estimation error is first presented in a linear context. As a result, the so-called separation principle for the controller and the fault identification scheme is developed. Subsequently, the proposed approach is extended to a class of non-linear systems. Similarly to the linear case, it is proven that using a suitable control strategy and a faulty identification scheme it is possible to obtain an integrated fault-tolerant control framework, which takes into account the fault identification error. As a result, a non-linear counterpart of the above-mentioned separation principle is developed. Finally, the last part of the paper shows the application results obtained using a twin-rotor system that confirm the high performance of the proposed approach.     

未知时变惯量航天器自适应姿态跟踪容错控制

针对存在未知时变惯量不确定性、执行机构衰退故障和外部干扰力矩的非刚体航天器系统,研究了航天器自适应姿态跟踪容错控制问题,结合非线性鲁棒控制方法、自适应方法、容错控制理论和参数估计方法,提出了一种鲁棒自适应姿态跟踪容错控制器。所设计的控制器克服了执行器故障、惯量不确定性以及外界干扰对系统稳定性的影响,保证了航天器姿态及角速度能够跟踪上时变的期望状态,实现了跟踪误差系统最终一致有界稳定。最后通过数字仿真验证了所提方法的有效性,并且与已有方法进行了对比,说明了所提方法的优越性。     

Observer-based fault-tolerant control for a class of nonlinear networked control systems

This paper presents a fault-tolerant control (FTC) scheme for nonlinear systems which are connected in a networked control system. The nonlinear system is first transformed into two subsystems such that the unobservable part is affected by a fault and the observable part is unaffected. An observer is then designed which gives state estimates using a Luenberger observer and also estimates unknown parameter of the system; this helps in fault estimation. The FTC is applied in the presence of sampling due to the presence of a network in the loop. The controller gain is obtained using linear-quadratic regulator technique. The methodology is applied on a mechatronic system and the results show satisfactory performance.