【作者】 张凤；

【导师】 连捷；

【作者基本信息】 大连理工大学 ， 控制理论与控制工程， 2011， 硕士

【摘要】 切换作为一种重要的控制策略广泛应用于各种控制系统的数学模型中,切换对系统动力学行为的影响也一直是理论研究的热点问题。在过去几十年里,学者们就切换系统提出许多重要的研究方法并取得大量出色的研究成果。但这些研究成果主要是针对切换子系统为确定性系统的情形,较之确定性系统,随机系统包含更为丰富的内容,也更符合工程实际系统常包含随机因素的特性。本文考虑一类系统动态受随机干扰影响,而切换规则仍为确定性函数的系统,采用积分型滑模控制方法,研究其在一类满足平均驻留时间条件的切换规则作用下的稳定性问题,主要工作包括以下几个方面：研究具有时变时滞的不确定切换随机系统的滑模控制问题。设计积分型滑模面,采用平均驻留时间方法和线性矩阵不等式(LMI)技术,给出滑动模态均方指数稳定的充分条件。然后设计变结构控制器,保证系统状态轨迹从初始时刻开始就保持在预先设计的滑模面上。针对一类广义切换随机时滞系统,研究其在异步切换下基于无源性的滑模控制问题。根据异步切换的特性,整个运行区间分为匹配区间和不匹配区间。设计积分型滑模面,构造一类满足平均驻留时间条件的切换信号,得出滑动模态在该切换信号的作用下在无外界干扰时均方指数稳定,以及受到外界干扰时随机无源且具有耗散率γ的充分条件。最后设计变结构控制器以保证系统对滑模面的可达性。针对一类具有不可测状态的切换随机时滞系统,研究其在异步切换下基于观测器的滑模控制问题。设计观测器来估计系统的状态,考虑观测器切换信号滞后于系统切换信号情况下积分型滑模面和变结构控制器的设计问题,并给出闭环系统均方指数稳定的充分条件。最后,对全文的主要工作进行总结,并指出下一步可能的工作内容。更多还原

【Abstract】 Switching as an important control strategy has been widely used in various system models. The effect of switching on system dynamical behaviors has always been a hot topic in theory. In recent years, many important methods and remarkable achievements have been developed. However, most of these results are associated with switched systems with deterministic subsystems. Compared with deterministic systems, stochastic systems contain much more information, and are more reasonable to indicate the characteristic that engineering systems usually include random factors. In this thesis, a class of systems is studied, in which system dynamics is affected by stochastic disturbances, while the switching signal is still a deterministic function. By applying integral type sliding mode control, the stability for a class of switching signals satisfying average dwell time is investigated. The main results obtained in this thesis are as follows:The problem of sliding mode control for uncertain switched stochastic systems with time-varying delays is investigated. Construct an integral type sliding surface, and derive sufficient conditions in the form of linear matrix inequalities (LMIs) for mean-square exponential stability of the sliding mode dynamics by an average dwell time method. Then, variable structure controllers are designed to guarantee the system trajectories remain on the predefined sliding surface from the initial time.For generalized switched stochastic systems, the passivity-based sliding mode control under asynchronous switching is studied. According to the characteristics of asynchronous switching, the entire time interval is divided into two parts:unmatched periods and matched periods. An integral type sliding surface and a class of switching signals satisfying average dwell time are constructed. Sufficient conditions for mean-square exponential stability and stochastic passivity with dissipation rateγare developed. Moreover, variable structure controllers are designed to guarantee the reachability of the sliding surface.Considering a class of switched stochastic systems with unmeasurable states, the problem of observer-based sliding mode control under asynchronous switching is investigated. An observer is designed to estimate the system state. In addition, the design problem of an integral type sliding surface and variable structure controllers are considered when the switching signal of the observer lags behind that of the system. Meanwhile, sufficient conditions for mean-square exponential stability of the closed-loop system are developed. Finally, draw a conclusion of the results of the thesis, and point out some problems which deserve future study.更多还原