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离散网络化控制系统的鲁棒滤波和控制
中文摘要

网络化控制系统是计算机技术、网络通信技术和控制技术的交叉融合。网络的引入使得控制系统中信息的传输方式发生了深刻的变化。在网络化控制系统中,数据信息在传输过程中会遇到一系列不可避免的问题,如信号:量化、通信时滞、数据包丢失、信道衰减和时序紊乱等,这些网络诱导现象和系统自身的不确定性、外部扰动、测量噪声、元器件的物理限制等因素一起导致了系统中信息的随机不确定性。为了降低这些随机不确定因素对系统性能的影响,我们亟需发展与之相适应的滤波和控制理论。 本论文针对网络化控制系统中的一些随机不确定因素,系统地研究了几类离散网络化非线性系统的鲁棒滤波和控制问题,提出了行之有效的滤波器和控制器设计方法。具体来说,主要研究内容和成果包括以下几个方面: (1)研究了具有增益不确定性和信道衰减的离散T-S模糊系统的非脆弱H〓滤波问题。利用Lyapunov稳定性理论和随机分析方法,得到了模糊滤波误差动态系统指数均方稳定且具有给定的H〓干扰衰减水平的充分条件。在此条件基础上,通过引入松弛变量,将模糊滤波器的设计问题转化为了具有线性矩阵不等式约束的凸优化问题,通过求解该优化问题可得到所设计滤波器的参数。 (2)研究了具有随机发生参数不确定性和信道衰减的一类离散非线性系统的有限时间指数耗散滤波问题。同时包含加性扰动和扰动相关白噪声的Rice衰减模型描述了现实中无线通信信道中的随机衰减现象。经过逐层分析和处理,推导出了滤波误差系统有限时间随机有界且满足指定指数耗散性能的充分条件。同时,给出了该不等式条件的求解方法和所设计滤波器参数的显式表达式。 (3)研究了具有随机发生参数不确定性和信道衰减的一类离散非线性系统的有限时间耗散控制器设计问题。通过深入分析,得到了能使闭环系统有限时间随机有界且满足指定指数耗散性能的状态反馈控制器存在的充分条件,并给出了求解该条件的锥补线性化迭代算法。 (4)考虑了具有控制器-执行器通道丢包补偿和执行器饱和的多胞型不确定离散系统的鲁棒分布式模型预测控制问题。将整个系统分成多个相互耦合的子系统,建立了新的分布式增广模型,在此模型基础上为每一个子系统分别设计了分布式模型预测控制器。最后将分布式模型预测控制的设计问题转化为了线性矩阵不等式优化问题的在线并行求解,给出了该优化问题的在线迭代求解算法并分析了算法的收敛性和系统的鲁棒稳定性。 通过数值算例,上述结果的有效性得到了验证。最后,对本文所做工作进行了总结,并指出了后续的研究方向。 关键词:非脆弱滤波 信道衰减 耗散滤波 耗散控制 模型预测控制

英文摘要

Networked control system is the cross-fusion of computer technology, network communication technology and control technology. The involvement of communication network has transformed the information transmission mode in control systems profoundly. In networked control systems, the data information encounters a series of inevitable problems in its transmission process, such as communication delays, data dropouts, channel fadings and packets disorders and so on. These network-induced phenomena together with the uncertainties in the system itself, the external disturbances, measurement noise and the physical limits of the devices, among other factors, lead to the stochastic uncertainties of the system information. In order to lower the impact of these randomness and uncertainties, it becomes a crucial issue to develop the relevant filtering and control theory. With regard to some stochastic uncertain factors in the networked systems, this thesis mainly studies the filtering and control problem for several classes of discrete time networked non-linear systems and presents some novel filter and controller design scheme. The main content and contribution of this thesis are as follows. (1)This paper aims at designing a full-order non-fragile H〓 fuzzy filtering is studied for a class of discrete networked Takagi-Sugeno (T-S) fuzzy system with gain uncertainties and channel fadings . Through the Lyapunov stability theory and the stochastic analysis method, a sufficient condition is derived to guarantee the fuzzy filtering error system is exponentially mean-square stable with a prespecified H〓 disturbance attenuation. Based on this condition, by introducing the slack variables, the filter design problem is translated into a convex optimization problem with the linear matrix inequality constraints and the designed filter parameters can be obtained by solving this problem. (2)The finite-time dissipative filtering problem is investigated for a class of discrete networked nonlinear system with the randomly occurring model uncertainties and channel fadings. A modified Rice fading model is introduced to describle the reality of the channel fadings, which includes not only the additive external disturbance but also the disturbance-dependent Gaussian white noise. Through the layer by layer analysis and processing, a sufficient condition is obtained which makes the filtering error system is finite-time stochastic bounded with the specified exponential dissipativity performance. Meanwhile, the corresponding solution method and the explicit representation of the filter parameters are given. (3)The finite-time dissipative control problem is considered for a class of discrete networked nonlinear system with the randomly occurring model uncertainties and channel fadings. Through the intensive analysis, the sufficient conditions for the existence of the state feedback controller are established, which make the closed system is finite-time stochastic bounded and satisfy the specified exponential dissipativity performance, and the cone complementarity linearization iterative algorithm is given to solve this condition. (4)The robust distributed model predictive control problem for the uncertain discrete networked system subject to actuator saturations and packet loss compensation in controller-to-actuator (C/A) channel. The global system is decomposed into several coupled subsystems and a novel augmented distributed controller model is proposed, based on which the distributed controllers are designed for each subsystem. Finally, the distributed model predictive controller design problem is converted into the parallel on-line solution of several sets of optimization problems involving linear matrix inequalities. Furthermore, an on-line iterative solving algorithm is proposed, then the convergence of the algorithm and the system robust stability are analysed. Numerical examples are supplied to demonstrate the effectiveness of the results above. Finally, a conclusion is drawn and some following study aspects are presented. KEY WORDS: Non-fragile filter Channel fadings Dissipative filter Dissipative control Model predictive control

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