参数不确定广义系统鲁棒H∞容错控制器的设计

研究了一类不确定广义系统基于状态反馈针对执行器发生故障的鲁棒H∞容错控制问题；运用线性矩阵不等式(LMI)给出了鲁棒H∞容错控制器存在的充分条件；通过假设失效的执行器的输出信号是任意的能量有界干扰信号，将不确定广义系统的鲁棒H∞容错控制问题化为H。控制问题，给出了该问题可解性的充分奈件。鲁棒H∞容错控制器可以通过解相应的线性矩阵不等式(LMI)给出，因而具有数值易解性。最后，所给的设计例子说明了方法的有效性。     

线性时滞不确定连续系统的鲁棒容错控制研究

以线性不确定时滞系统为模型,应用李雅普诺夫稳定性理论和LMI工具箱,采用状态反馈控制器设计连续系统的容错控制器,研究了线性不确定时滞连续系统的状态反馈鲁棒稳定问题.给出了系统在执行器失效情况下渐近稳定的充分条件及相应的状态反馈鲁棒容错控制器的设计方法,仿真结果验证了该方法的可靠性和有效性.     

线性定常连续系统的容错控制研究

研究了线性定常连续系统的鲁棒容错控制问题。利用线性矩阵不等式（LMI）方法,给出了系统在执行器失效情况下系统渐进稳定的充分条件以及含执行器故障的线性定常系统的设计方法,仿真研究验证了方法的可靠性和有效性。     

永磁直线伺服系统非线性自适应鲁棒控制器设计

对永磁直线伺服系统提出非线性自适应鲁棒控制器的设计方法。在永磁直线伺服系统非线性数学模型的基础上,为实现对速度和电流的准确跟踪,建立了误差系统的动态模型。将跟踪和干扰抑制归结为非线性自适应鲁棒控制器设计问题,通过构造存储函数得到包含电阻辨识算法的自适应鲁棒控制器的定理,证明定理给出的控制器能满足干扰抑制和系统的渐进稳定。仿真结果表明,用该方法设计的系统能很好的抑制扰动和跟踪给定,满足对高性能永磁直线伺服系统控制的要求。     

执行器非线性超低空空投航迹倾角自适应控制

针对超低空空投下滑阶段执行器非线性、外界不确定性大气扰动以及模型存在未知非线性等因素干扰轨迹精确跟踪问题,提出一种鲁棒自适应神经网络动态面跟踪控制方法。建立了含执行器输入非线性的超低空空投载机纵向非线性模型,采用神经网络逼近模型中未知非线性函数,引入非线性鲁棒补偿项消除了执行器非线性建模误差和外界扰动。应用Lyapunov稳定性理论证明了闭环系统所有信号均是有界收敛的。仿真验证了所提方法既保证了轨迹跟踪的精确性又具有较强的鲁棒性。     

基于T-S模糊模型的鲁棒自适应滑模控制

针对一类具有时滞的非线性连续时间系统,基于T—S模糊模型,考虑系统的外界干扰和建模误差不存在的理想情况,并利用滑模控制理论和LMI方法,设计了滑模控制器;考虑系统的外界干扰和建模误差存在的情况,采用神经网络逼近建模误差,引入自适应控制鲁棒项,设计了自适应滑模控制器,根据Lyaponuv稳定性理论,证明了系统状态渐近稳定。仿真示例表明了所提方法的有效性。     

不确定混沌电力系统的鲁棒自适应跟踪控制

针对混沌电力系统的跟踪控制问题,在考虑系统含有常参数不确定性及未知干扰的前提下,采用动态面控制方法,设计了鲁棒自适应跟踪控制器,保证了闭环系统的半全局渐近稳定,进而使输出渐近跟踪参考轨迹.理论分析及仿真结果表明,所设计的自适应非线性控制器能够有效抑制简单电力系统的混沌振荡,且具有一定的适应性及鲁棒性.     

卫星姿控系统的滑模容错控制及主动振动抑制

针对执行机构故障情况下挠性卫星姿态控制系统的容错控制及主动振动抑制问题,建立轨控推力扰动条件下含执行器故障的挠性卫星姿态控制系统模型,采用自适应控制方法设计该姿控系统的高阶滑模容错控制器,并在姿态稳定的基础上设计基于高阶滑模的补偿项以降低挠性振动对姿态精确度的影响。对轨控期间飞轮正常情形及故障情形下的挠性卫星姿态仿真结果表明,在卫星姿态控制系统存在干扰的条件下,该方法能实现对执行器故障的容错能力并能提高姿态控制精确度。     

IGCC电站中气化炉H∞非脆弱鲁棒解耦与控制研究

IGCC电站中的气化炉具有延迟等模型不确定性.控制器(包括执行器)的实现也不可能充分精确.给出了气化炉被控对象和控制器同时摄动时的非脆弱鲁棒性能设计概念,解决了常规设计不能保证系统具有非脆弱鲁棒性的问题.根据水蒸气量对煤气热值影响可以忽略的特点,并且利用鲁棒控制的干扰概念,提出了鲁棒解耦的观点,将MIMO系统非脆弱鲁棒性能设计简化为两个SISO系统的设计.提出了通过修改不确定性权函数和性能权函数可转化为用H∞混合灵敏度求解非脆弱鲁棒控制器的一种设计方法.研究了权函数的选择,求解了H∞非脆弱鲁棒PI控制器.仿真结果表明,本文提出的设计方法是有效的.     

VSC-HVDC直流电压的鲁棒控制策略研究

在VSC-HVDC系统分析、设计过程中最棘手的问题是如何处理非线性系统中的不确定性。注意到在d-q同步旋转坐标系下的VSC-HVDC连续时间状态空间模型中直流电压微分方程为非线性,针对其物理过程易受到不确定性的外界干扰的影响设计了鲁棒控制器。通过仿真与线性控制器进行了比较,结果表明鲁棒控制器增加了VSC-HVDC系统的稳定性。     

Output feedback adaptive fault-tolerant compensation tracking control for linear systems based on the closed-loop reference model

This paper investigates the problem of output feedback adaptive compensation tracking control for linear systems subject to external disturbances and actuator failures including loss of effectiveness faults and bias faults. The impact of actuator faults on the transient performance of systems can be mitigated predicated on the closed-loop reference model with an additional degrees of design freedom. Using the estimation information provided by the adaptive mechanism, an output feedback adaptive fault-tolerant control strategy is developed to track closed-loop reference model systems. It is shown that all the signals of the resulting closed-loop system are bounded. Finally, simulation results are given to demonstrate the effectiveness of the proposed fault-tolerant tracking control method.     

Model‐free fault‐tolerant control approach for uncertain state‐constrained linear systems with actuator faults

This paper investigates the robust adaptive fault‐tolerant control problem for state‐constrained continuous‐time linear systems with parameter uncertainties, external disturbances, and actuator faults including stuck, outage, and loss of effectiveness. It is assumed that the knowledge of the system matrices, as well as the upper bounds of the disturbances and faults, is unknown. By incorporating a barrier‐function like term into the Lyapunov function design, a novel model‐free fault‐tolerant control scheme is proposed in a parameter‐dependent form, and the state constraint requirements are guaranteed. The time‐varying parameters are adjusted online based on an adaptive method to prevent the states from violating the constraints and compensate automatically the uncertainties, disturbances, and actuator faults. The time‐invariant parameters solved by using data‐based policy iteration algorithm are introduced for helping to stabilize the system. Furthermore, it is shown that the states converge asymptotically to zero without transgression of the constraints and all signals in the resulting closed‐loop system are uniformly bounded. Finally, two simulation examples are provided to show the effectiveness of the proposed approach. Copyright © 2016 John Wiley & Sons, Ltd.     

Adaptive fuzzy dual-performance fault-tolerant control for interconnected nonlinear systems

This article focuses on the decentralized adaptive fuzzy fixed-time fault-tolerant control issue for the error-constrained interconnected nonlinear systems with unknown actuator faults possessing dead zone. The unknown nonlinear functions can be modeled via fuzzy logic systems. By utilizing the parameter estimation method, the effect of unknown actuator faults possessing dead zone can be compensated. To guarantee the predefined dynamic performance of state tracking errors, the barrier Lyapunov functions and prescribed performance functions are introduced. Then, a dual-performance fault-tolerant control method that can guarantee fast transient performance and predefined performance of state tracking errors is proposed via using the decentralized backstepping technique. In addition, on the basis of the Lyapunov stability theory and the fixed-time criterion, it is proved that the predefined performance of full-state errors and the stability of closed-loop systems can be guaranteed. Finally, two numerical examples are provided to illustrate the effectiveness of the proposed control scheme.     

Finite time adaptive fault-tolerant controller based on neural networks for switched stochastic nonlinear systems with actuator failures and disturbance

This article investigates the novel finite time adaptive neural fault-tolerant controller (FTC) for strict-feedback switched stochastic systems under arbitrary switching signals and takes into actuator failures including loss of effectiveness faults and bias faults consideration concurrently. Neural networks are utilized to approximate the unknown external disturbance and internal dynamics. On the basis of Itô differential equation and backstepping technique, an adaptive neural finite time FTC method is put forward. It is attested that the closed-loop systems are semiglobal practical finite time stable in probability and the tracking effects are great. Finally, to further demonstrate the high efficiency of proposed control method, two simulation examples are given.     

不确定性时滞关联大系统的分散变结构自适应控制

针对一类具有系统参数摄动、时滞关联和外界干扰的线性大系统,提出了一种基于Lyapunov稳定性理论的分散变结构自适应控制方案。通过引入积分滑模和能在线估计不确定性扰动与时滞关联的界的自适应算法,保证了闭环系统的渐近稳定性,实现了系统的鲁棒自适应控制。该方案具有较强的工程实用性,算例仿真的结果表明了该控制方案的可行性。     

Robust adaptive output‐feedback control for a class of nonlinear systems with time‐varying actuator faults

A robust adaptive output‐feedback control scheme is proposed for a class of nonlinear systems with unknown time‐varying actuator faults. Additional unmodelled terms in the actuator fault model are considered. A new linearly parameterized model is proposed. The boundedness of all the closed‐loop signals is established. The desired control performance of the closed‐loop system is guaranteed by appropriately choosing the design parameters. The properties of the proposed control algorithm are demonstrated by two simulation examples. Copyright © 2010 John Wiley & Sons, Ltd.     

Robust adaptive active fault‐tolerant control of UAH with unknown disturbances and actuator faults

This paper proposes a robust active fault‐tolerant control (AFTC) approach for medium‐scale unmanned autonomous helicopter (UAH) with rotor flapping dynamics in the presence of unknown external disturbances and actuator faults. The robust items are adopted to improve the disturbance rejection capability of the UAH system. The adaptive fault observers are developed to estimate the fault parameters and the fault detection (FD) algorithms are presented to detect the actuator faults in different loops. In order to obtain satisfactory trajectory tracking performance, a backstepping‐based robust AFTC scheme is designed for the simplified 6‐degree‐of‐freedom (DOF) UAH nonlinear dynamics model and the global stability of the closed‐loop system is proved by using the Lyapunov method. Several groups of numerical simulation results are carried out to verify the effectiveness of the developed method.     

Hierarchical structure-based adaptive fault-tolerant consensus control for multiple 3-DOF laboratory helicopters

This study investigates the consensus problem of multiple 3-DOF laboratory helicopters modeled with system nonlinearity, uncertainty, and actuator faults. The simultaneous additives and partial loss of effectiveness actuator faults are considered. The fault detection hierarchy, the healthy control hierarchy, and the fault-tolerant control hierarchy constitute the hierarchical structure of multihelicopter systems. The fault-tolerant consensus protocol is switched from the healthy control hierarchy once the actuator fault is detected in the fault detection hierarchy. An adaptive fault-tolerant consensus control scheme is developed on the basis of the instantaneous and integral estimations to compensate simultaneously for system nonlinearity, uncertainty, and actuator faults and to guarantee the mean-square consensus in a completely distributed form. Simulation results are presented to validate the effectiveness of the proposed adaptive fault-tolerant consensus control algorithm.     

Accommodation of unknown actuator faults using output feedback‐based adaptive robust control

In this paper, we solve the problem of output tracking for linear uncertain systems in the presence of unknown actuator failures using discontinuous projection‐based output feedback adaptive robust control (ARC). The faulty actuators are characterized as unknown inputs stuck at unknown values experiencing bounded disturbance and actuators losing effectiveness at unknown instants of time. Many existing techniques to solve this problem use model reference adaptive control (MRAC), which may not be well suited for handling various disturbances and modeling errors inherent to any realistic system model. Robust control‐based fault‐tolerant schemes have guaranteed transient performance and are capable of dealing with modeling errors to certain degrees. But, the steady‐state tracking accuracy of robust controllers, e.g. sliding mode controller, is limited. In comparison, the backstepping‐based output feedback adaptive robust fault‐tolerant control (ARFTC) strategy presented here can effectively deal with such uncertainties and overcome the drawbacks of individual adaptive and robust controls. Comparative simulation studies are performed on a linearized Boeing 747 model, which shows the effectiveness of the proposed scheme. Copyright © 2011 John Wiley & Sons, Ltd.     

Robust adaptive control of nonlinearly parameterized systems with unmodeled dynamics

Many physical systems such as biochemical processes and machines with friction are of nonlinearly parameterized systems with uncertainties. How to control such systems effectively is one of the most challenging problems. This paper presents a robust adaptive controller for a significant class of nonlinearly parameterized systems. The controller can be used in cases where there exist parameter and nonlinear uncertainties, unmodeled dynamics and unknown bounded disturbances. The design of the controller is based on the control Lyapunov function method. A dynamic signal is introduced and adaptive nonlinear damping terms are used to restrain the effects of unmodeled dynamics, nonlinear uncertainties and unknown bounded disturbances. The backstepping procedure is employed to overcome the complexity in the design. With the proposed method, the estimation of the unknown parameters of the system is not required and there is only one adaptive parameter no matter how high the order of the system is and how many unknown parameters there are. It is proved theoretically that the proposed robust adaptive control scheme guarantees the stability of nonlinearly parameterized system. Furthermore, all the states approach the equilibrium in arbitrary precision by choosing some design constants appropriately. Simulation results illustrate the effectiveness of the proposed robust adaptive controller. __________ Translated from Journal of Sichuan University (Engineering Science Edition), 2005, 37(5): 148–153 (in Chinese)