具有数据丢失二维Roesser系统的量化状态反馈控制

探讨存在数据丢失二维Roesser系统的量化状态反馈控制器设计问题。假设二维系统在网络控制系统中运行且系统状态全部可测,测量到的状态数据量化后经网络进行传输,同时由于网络自身限制伴随数据包丢失现象的发生。首先将数据丢失描述成取值为0或1的随机伯努利序列,定义了随机意义下二维系统的均方稳定性。其次,采用扇形界方法处理数据量化造成的误差,给出一个闭环系统均方渐进稳定的充分条件,基于该条件可通过求解线性矩阵不等式设计状态反馈控制器。最后,仿真示例验证了所提设计方法的有效性。     

有限时间镇定及其在电机速度控制中的应用

针对线性系统有限时间稳定并满足一定性能指标的控制器设计问题,结合有限时间有界与有限时间输入输出镇定方法,给出了满足性能约束的充分条件和状态反馈控制器的设计方法。而后将此方法应用于航天器控制力矩陀螺外框电机控制设计中,其目的是在理论上严格保证系统的某些状态有界,同时利用事先给定的有限时间区间满足系统的动态品质需求。仿真结果表明:加入控制器的闭环系统能快速跟踪参考信号,同时电流值亦能满足预先在不同时段给定的界。     

时滞不确定系统的广义H2控制

研究了一类同时具有时变状态时滞和凸多面体不确定性的连续时间系统的广义H2控制问题，采用线性矩阵不等式技术推导了此类不确定系统的鲁棒L2－L∞状态反馈控制器存在的充分条件，并将控制器的设计转化为一个凸优化的求解问题，所设计的控制器能够保证相对于所有能量有界的外界扰动信号，闭环系统的L2－L∞性能指标小于一定值，数值仿真验证了所提出方法的可行性。     

不确定广义系统的可靠保性能控制

针对一类含有时变、范数有界参数不确定广义系统,结合一个二次型性能指标,研究了广义系统执行器出现故障时,故障闭环系统保持正则、稳定、无脉冲,且闭环性能指标不超过某个确定界的状态反馈可靠保性能控制律的设计问题.利用线性矩阵不等式(LMI),给出了可靠保性能状态反馈控制器存在的充分条件及设计方法.数值算例验证了设计方法的有效性.     

轧机液压伺服位置系统的自适应输出反馈控制

针对具有不可测状态、未知参数和非线性的轧机液压伺服位置系统,提出一种基于高增益观测器和参数估计器的自适应输出反馈控制算法.所构造的高增益观测器不依赖于系统输入和参数估计值,它只用于估计系统状态,所设计的动态反馈控制器包括:用于保证系统稳定性的主反馈部分和抵消外部扰动和一些不确定性的补偿部分.理论分析表明,所提出的控制算法能够保证闭环系统的所有信号有界,且系统状态及其估计误差的最终收敛边界依赖于观测器的高增益值.以某650 mm可逆冷带轧机液压伺服位置系统为例进行仿真,仿真结果验证了所提出算法的有效性.     

基于LMI的奇异不确定时滞系统鲁棒保成本控制

针对一类奇异不确定时滞系统的鲁棒保成本控制,假定其中的不确定性是范数有界,采用基于线性矩阵不等式（LMI）和构造适当的Lyapunov泛函相结合的方法,给出了系统的鲁棒保成本状态反馈控制器存在的条件。通过求解相应的线性矩阵不等式就可得到鲁棒保成本控制,所设计的保成本控制器对所有容许的不确定性不仅使得相应的闭环系统达到二次稳定,也能保证闭环成本函数不超过一个确定的界。通过数值算例及仿真验证了所给方法的有效性。     

基于结构保留模型的静止无功补偿器鲁棒非线性控制

采用Hamilton函数方法研究了静止无功补偿器(SVC)的鲁棒非线性控制问题。首先基于系统网络结构特点,建立了包含SVC、恒功率负荷和有界外部扰动的电力系统的结构保留不确定非线性控制数学模型,然后通过坐标变换和预置状态反馈控制完成了系统的耗散Hamilton实现。最后,基于该耗散实现设计了鲁棒控制器,并分析了闭环系统的渐近稳定性。由于充分利用了系统的内在耗散结构特性,所设计的鲁棒控制器物理意义明确,易于实现。与常规PID控制器的仿真比较表明,该鲁棒控制器作用下系统的超调量小、响应速度快,能有效抑制外部干扰对系统暂态稳定性的影响,有效提高了系统的动态性能。     

不确定刚性机械臂的鲁棒输出控制

针对不确定刚性机械臂系统的鲁棒控制和抖振问题,在仅有精确关节位置反馈的情况下,通过引入速度滤波器生成伪速度信号,并利用反推补偿设计滤波增益,提出了一种基于速度估计的鲁棒输出反馈控制策略。滤波器-控制器设计中不合有开关控制项,有效避免了控制抖振现象。该算法对采样频率无严格限制,最终可确保系统闭环半全局一致有界收敛。通过两关节机械臂的仿真实例验证了所提算法的有效性。     

轻型直流输电系统鲁棒非脆弱H∞控制器设计

建立了轻型直流输电系统dq0坐标系下的电压源型换流器被控对象的状态空间方程,考虑到模型参数的不确定性和不确定系统的控制器参数在一定范围内发生加性范数有界摄动的情况。利用线形矩阵不等式（LMI）方法对鲁棒非脆弱H∞状态反馈控制器的设计进行了研究,然后分别对输电系统整流侧和逆变侧设计了鲁棒非脆弱H∞控制器。最后建立了MATLAB仿真模型,将所设计的控制器与H∞控制器进行仿真分析,仿真结果表明所设计的控制器具有良好的非脆弱性和鲁棒性。     

具有有界控制输入的线性时变系统闭环稳定性

对于线性时变系统,本文基于李雅普诺夫定量,给出了具有有界控制输入的状态反馈控制系统的闭环渐近稳定性判据,这些判据具有简单的形式和较少的保守性。     

Robust fault tolerant control for a class of networked control systems with state delay and stochastic actuator failures

This paper is concerned with the robust fault tolerant controller design of networked control systems (NCSs) with state delay and stochastic actuator failures. By utilizing the input delay approach, an equivalent continuous‐time generalized time delay system in both state and input is obtained. By applying a delay decomposition approach, the information of the delayed plant states can be taken into full consideration, and new delay‐dependent sufficient conditions that ensure the asymptotic mean‐square stability of NCSs with stochastic actuator failures are derived in terms of linear matrix inequalities (LMIs). It is realized by employing a new Lyapunov–Krasovskii function in the decomposed integral intervals and directly handle the inversely weighted convex combination of quadratic terms of integral quantities with reciprocally convex combination technique. Moreover, the proposed approach involves neither slack variable nor any model transformation. A numerical example is provided to demonstrate the effectiveness and less conservatism of the proposed method.Copyright © 2012 John Wiley & Sons, Ltd.     

网络控制系统的有界输入保性能控制及仿真

针对网络控制系统中存在的数据传输时延，以及由被控对象和控制器之间的不同步给系统所带来的稳定性问题，提出了鲁棒保性能控制器设计方案。将网络系统中的时延的不确定，转化为系统状态方程参数矩阵的不确定；根据实际系统中对控制器输出信号的幅值约束的要求，设计了状态反馈控制律，对导出的闭环网络控制系统应用Lyapunov稳定性理论进行稳定性分析，给出了使系统稳定的充分条件；通过求解线性矩阵不等式得到反馈增益矩阵和系统性能指标上界值。将鲁棒保性能控制器设计方案应用于直流电机系统中，仿真结果验证了所提方案的正确性。与补偿策略的比较，进一步说明了所提控制策略的有效性。     

随机最优非线性网络控制系统设计

针对网络控制非线性系统中存在的不确定时延,利用Delta算子方法,研究了基于T-S模糊模型的随机最优网络控制问题。采用T-S模型模糊动态逼近非线性系统,将非线性模型模糊化为局部线性模型,设计了本质为非线性的具有时延补偿功能的状态反馈控制器,并进行了稳定性分析,并仿真。结果表明,所提出的建模方法是可行的,实质为非线性的状态反馈的控制器能够有效地补偿时延对系统性能的影响,且补偿效果好。     

Decentralized robust adaptive-output feedback controller for power system load frequency control

In this paper, a new model reference-decentralized robust adaptive-output feedback controller is proposed for the load frequency control (LFC) of large-scale power systems with unknown parameters. This control strategy requires only local input–output data and can follow random changes in the operating conditions. The controller is designed such that the trajectory errors and the control gains of each area remain uniformly bounded. In the proposed method, firstly an adaptive observer is designed to estimate the state variables and system parameters using local data only. Then a locally linear combination of the estimated states and the model reference states are used to design a robust adaptive-output feedback controller for each area. Simulation results for a three-area power system show that the proposed controller achieves good performance even in the presence of plant parameter changes and system non-linearities. Received: 18 October 2001/Accepted: 24 October 2001     

State‐feedback stabilization for a class of more general high order stochastic nonholonomic systems

This paper studies the problem of state‐feedback stabilization control for a class of high order stochastic nonholonomic systems with disturbed virtual control directions and more general nonlinear drifts. By using the backstepping approach, we develop a recursive controller design procedure in the stochastic setting. To get around the stabilization burden associated with nonholonomic systems, a switching control strategy is exploited in this procedure. The tuning function technique is applied in the design to avoid the disadvantage of overparameterization. It is shown that, under some conditions, the designed controller could ensure that the closed‐loop system is almost asymptotically stabilized in probability. It is noted that the obtained conclusion can be extended to multi‐input systems. A simulation example is provided to illustrate the effectiveness of the proposed approach. Copyright © 2011 John Wiley & Sons, Ltd.     

Adaptive neural finite-time output-feedback tracking control for nonlinear stochastic nonstrict-feedback systems with input saturation

In this paper, an observer-based adaptive neural output-feedback control scheme is developed for a class of nonlinear stochastic nonstrict-feedback systems with input saturation in finite-time interval. The mean value theorem and the property of the smooth function are applied to cope with the difficulties caused by the existence of input saturation. According to the universal approximation capability of the radial basis function neural network, it will be utilized to compensate the unknown nonlinear functions. Based on the state observer, the finite-time Lyapunov stability theorem, we propose an adaptive neural output-feedback control scheme for nonlinear stochastic systems in nonstrict-feedback form. The developed controller guarantees that the system output signal can track the given reference signal trajectory, and all closed-loop signals are semi-globally finite-time stability in probability. The observer errors and the tracking error can converge to a small neighborhood of the origin. Finally, simulation results demonstrate the effectiveness of the developed control scheme.     

Robust l2−l∞ dynamic output feedback control design for uncertain discrete-time switched systems with random time-varying delay

This article deals with the problem of robust output feedback control design for a class of switched systems with uncertainties and random time-varying delay. Our purpose is focused on designing a full order dynamic output feedback controller and an appropriate switching rule to ensure the exponential mean square stability of the resulting closed-loop switching system with an l₂−l_∞ performance level. The appealing aspects of the proposed control scheme include: (a) the development of LMI based delay-dependent sufficient conditions for the exponential stability analysis of the stochastic hybrid systems using the appropriate choice of the augmented Lyapunov–Krasovskii functional, the partitioning technique and the average dwell time, (b) conservatism reduction of the unified design conditions, and (c) the controller designed exhibiting robustness with l₂−l_∞ performance against uncertainties and external disturbance. Finally, representative examples are given to demonstrate the validity and the merit of the proposed design technique.     

非线性网络化控制系统鲁棒容错控制

针对具有马尔可夫特性时延的网络化控制系统,基于时延准T-S模型,考虑系统参数不确定性的影响,采用状态反馈控制律,通过构造离散Lyapunov泛函,推证出了确保网络化控制系统在传感器发生失效故障时具有鲁棒完整性的充分条件,并以求解LMIs给出容错控制器的设计方法。最后通过仿真验证了文中所述方法的可行性和有效性。     

不确定时滞广义T-S模糊系统的鲁棒镇定

研究了不确定时滞广义T-S模糊系统的鲁棒镇定问题.基于李亚普诺夫稳定性定理和线性矩阵不等式(LMI)方法,给出了使闭环系统稳定的条件,采用凸优化的方法求解一组线性矩阵不等式可以得到状态反馈控制器的参数.仿真实例验证了本文所提出方法的有效性.     

Decentralized adaptive output‐feedback control for stochastic interconnected systems with stochastic unmodeled dynamic interactions

In this paper, we consider the problem of decentralized adaptive output‐feedback regulation for stochastic nonlinear interconnected systems with unknown virtual control coefficients, stochastic unmodeled dynamic interactions. The main contributions of the paper are as follows: (1) This paper presents the first result on decentralized output‐feedback control for stochastic nonlinear systems with unknown virtual control coefficients; (2) For stochastic interconnected systems with stochastic integral input‐to‐state stable unmodeled dynamics, and more general nonlinear uncertain interconnections which depend upon the outputs of subsystems and the stochastic unmodeled dynamics, a decentralized output‐feedback controller is designed to drive the outputs and states to the origin almost surely. Copyright © 2011 John Wiley & Sons, Ltd.