一类随机非线性系统的有限时间H∞控制

本文研究一类随机非线性系统的有限时间H_∞控制问题.考虑闭环系统在有限时间间隔内的瞬态性能和抗干扰能力,对伊藤型随机非线性系统进行了研究.利用Lyapunov函数和线性矩阵不等式(LMI)得到了系统满足均方有限时间有界的充分条件,进一步设计了有限时间H_∞控制器,并给出了系统满足均方有限时间有界和相应H_∞性能的充分条件.最后给出了两个例子验证了该方法的有效性和可行性.     

量化状态反馈网络化系统的稳定性分析

针对网络控制系统(Networked Control System,NCS)中普遍存在的有限带宽和信息量化问题,采用基于模型的控制策略,研究了量化状态反馈下一类网络控制系统的稳定性.分析了量化误差、更新时间、模型误差对系统稳定性的影响,并给出了系统模型状态、对象状态的稳定域范围.仿真结果表明了结论的正确性.     

具有时延和丢包的网络控制系统H_∞状态反馈控制

研究了具有时延和数据包丢失的网络控制系统H∞状态反馈控制问题.考虑了网络控制系统中同时存在时延和数据包丢失的情况.将丢包过程建模为有限状态的马尔可夫过程.在此模型的基础上,利用Lyapunov稳定性理论和线性矩阵不等式方法.给出了保持系统均方稳定且满足H∞性能的控制器存在的充分条件,并给出了相应的设计方法.最后数例仿真结果表明了控制器设计方法的有效性.     

变采样网络控制系统的最优保性能控制

研究了一类不确定时延网络控制系统的最优保性能控制问题.针对线性时不变控制对象,控制器和控制对象采用时间-事件驱动,系统成为变采样网络控制系统,考虑在不确定时延小于或者等于一个变采样周期时,基于动态输出反馈对变采样网络控制系统进行建模,利用线性矩阵不等式研究了系统的保性能控制,并设计了保性能控制率和最优保性能控制率,最后给出实例表明在最优保性能控制率的控制下系统稳定.     

基于移动机器人机载视觉云台的有限时间目标跟踪控制

研究面向移动目标的移动机器人机载视觉云台跟踪控制系统.首先,对视觉云台跟踪控制系统进行数学建模;然后,为提高移动目标的跟踪快速性和精度,基于有限时间控制技术提出一种新的有限时间视觉跟踪控制算法.严格的理论分析证明即使系统存在外部干扰也可以在有限时间内跟踪上目标,即通过控制云台转动能够保持在机器人运动过程中移动目标始终在相机视觉中心.仿真结果表明,所提出的有限时间控制算法可以实现移动目标的有限时间跟踪.     

量化状态反馈网络化系统的稳定性分析

针对网络控制系统（Networked Control System,NCS）中普遍存在的有限带宽和信息量化问题,采用基于模型的控制策略,研究了量化状态反馈下一类网络控制系统的稳定性。分析了量化误差、更新时间、模型误差对系统稳定性的影响,并给出了系统模型状态、对象状态的稳定域范围。仿真结果表明了结论的正确性。     

离散线性系统有限频域基于观测器的迭代学习控制

针对一类离散线性系统,在有限频域范围内研究基于观测器的迭代学习控制问题.首先,结合二维系统理论,构建由基于观测器的状态反馈和PID型前馈学习项组成的控制器;然后,借助于广义Kalman-Yakubovich- Popov(KYP)引理,将闭环系统有限频域性能规范转换为相应的线性矩阵不等式(LMI),进而得到控制器和观测器存在的充分条件,同时,该条件也确保闭环控制系统的稳定性和跟踪误差单调收敛性;最后,通过桁架机器人系统的仿真,验证所提出设计方法的有效性.     

长时延和丢包的网络控制系统保性能控制

为了研究具有长时延和丢包的网络控制系统保性能控制问题,假设传感器由时钟驱动,控制器和执行器由事件驱动,网络时延在两个采样周期之间,丢包具有马尔科夫跳变特性,利用状态增广的方法,把具有长时延和丢包的网络控制系统建模为具有两种运行模式的离散时间马尔可夫跳变系统,把网络时延转化为系统参数矩阵的不确定性.在此基础上,利用马尔可夫线性跳变系统理论和线性矩阵不等式方法,推导出使网络控制系统随机稳定的保性能控制律存在的充分条件,并给出了设计方法.数例仿真说明了所用方法的有效性.     

输入饱和受限下的刚体飞行器姿态系统的有限时间镇定

研究存在输入饱和受限下的飞行器姿态控制问题, 提出一种有限时间姿态镇定方案. 针对基于修改的Rodriguez 参数模型的飞行器姿态控制系统, 基于齐次性理论和饱和控制器设计方法, 并充分利用系统的模型结构特征, 设计一类饱和的有限时间姿态控制器, 使得姿态可以在有限时间内被镇定到平衡点. 仿真结果验证了所设计姿态控制器的有效性.

     

带宽约束下网络化控制系统的量化研究综述

为了寻求确保系统稳定性的最小比特数,针对线性网络化控制系统,综述研究量化比特个数、系统稳定性、系统噪声之间的普遍关系的一些重要结果;针对非线性网络化控制系统,回顾一般系统中有限个量化比特能确保稳定性的一些结果;并综述了系统采取一类较普遍的非线性前馈型情况下的、一些关于能确保系统稳定性的最小比特数方面的研究,并利用仿真对...     

Global finite-time control for a class of switched nonlinear systems with different powers via output feedback

This paper is concerned with the problem of global finite-time control for switched nonlinear systems whose nonlinear terms satisfy homogenous growth conditions. At first, we design homogenous output feedback controllers for nominal switched nonlinear systems by adding a power integrator method. Then, we employ the homogeneous domination approach to scale homogeneous observers and controllers to render switched nonlinear systems with lower-triangular homogenous growth condition globally finite-time stable. Finally, the proposed control method can be extended to switched nonlinear systems satisfying with upper-triangular homogeneous growth condition. Two examples are provided to demonstrate the effectiveness of the proposed control scheme.     

一类二阶非线性系统的有限时间状态反馈镇定方法

针对一类二阶非线性系统的有限时间状态反馈镇定问题进行了讨论. 给出了三种基于连续状态反馈的全局有限时间状态反馈镇定方法. 首先，利用非线性齐次系统性质，设计出一种状态反馈控制器，使得闭环系统渐近稳定并且具有负的齐次度；其次，基于有限时间Lyapunov函数的反步构造法，给出了一种有限时间控制器；最后，利用非奇异终端滑模控制技术，得到了一种使闭环系统有限时间收敛到平衡点的反馈镇定控制器. 仿真结果表明了这些方法的有效性.     

Event-triggered finite-time dynamic output feedback control for switched affine systems with asynchronous switching

This paper investigates the event-triggered finite-time dynamic output feedback control for switched affine systems (SASs) with asynchronous switching. A key point of the study is to set up a dynamic output feedback switched affine controller together with an event-triggered mechanism (ETM). By using an average dwell time (ADT) approach and resorting to a controller-mode-dependent Lyapunov functional, the finite-time stability (FTS) performance is achieve for the closed-loop SASs. The system dynamics under the proposed ETM are fully discussed during the synchronous and asynchronous switching intervals. The existence of the lower bound on interevent intervals is discussed emphatically, which excludes the occurrence of Zeno behavior. Finally, an application example of the DC-DC converter is given to show effectiveness of the acquired control algorithm.     

Finite-time stabilization via dynamic output feedback

In this paper the finite-time stabilization of continuous-time linear systems is considered; this problem has been previously solved in the state feedback case. In this work the assumption that the state is available for feedback is removed and the output feedback problem is investigated. The main result provided is a sufficient condition for the design of a dynamic output feedback controller which makes the closed loop system finite-time stable. Such sufficient condition is given in terms of an LMI optimization problem; this gives the opportunity of fitting the finite-time control problem in the general framework of the LMI approach to the multi-objective synthesis. In this context an example illustrates the design of a controller which guarantees, at the same time, finite-time stability together with some pole placement requirements.     

Finite-time output feedback stabilisation for a class of feedforward nonlinear systems with input saturation

This paper considers the problem of global finite-time stabilisation by output feedback for a class of feedforward (upper triangular) nonlinear systems with input saturation. Based on the finite-time stability theorem, and by skillfully using the homogeneous domination approach and the nested saturation technique, a saturated output feedback controller is successfully constructed, which renders the origin of the closed-loop system globally finite-time stable. In simulation studies, a numerical example is illustrated to show the effectiveness of the control scheme. Moreover, the design strategy is successfully applied to solve the saturated finite-time control problem for vertical wheel on rotating table.     

Finite-time consensus of time-varying nonlinear multi-agent systems

This paper investigates the problem of leader–follower finite-time consensus for a class of time-varying nonlinear multi-agent systems. The dynamics of each agent is assumed to be represented by a strict feedback nonlinear system, where nonlinearities satisfy Lipschitz growth conditions with time-varying gains. The main design procedure is outlined as follows. First, it is shown that the leader–follower consensus problem is equivalent to a conventional control problem of multi-variable high-dimension systems. Second, by introducing a state transformation, the control problem is converted into the construction problem of two dynamic equations. Third, based on the Lyapunov stability theorem, the global finite-time stability of the closed-loop control system is proved, and the finite-time consensus of the concerned multi-agent systems is thus guaranteed. An example is given to verify the effectiveness of the proposed consensus protocol algorithm.     

Global finite-time stabilization of a class of uncertain nonlinear systems

This paper studies the problem of finite-time stabilization for nonlinear systems. We prove that global finite-time stabilizability of uncertain nonlinear systems that are dominated by a lower-triangular system can be achieved by Hölder continuous state feedback. The proof is based on the finite-time Lyapunov stability theorem and the nonsmooth feedback design method developed recently for the control of inherently nonlinear systems that cannot be dealt with by any smooth feedback. A recursive design algorithm is developed for the construction of a Hölder continuous, global finite-time stabilizer as well as a C¹ positive definite and proper Lyapunov function that guarantees finite-time stability.     

Global finite-time output feedback stabilisation for a class of switched high-order nonlinear systems

This paper studies the problem of global finite-time output feedback stabilisation for a class of switched high-order nonlinear systems under arbitrary switchings. Based on adding one power integrator technique, we design a common homogeneous controller to guarantee finite-time stability of the closed-loop switched nonlinear system. An example is given to illustrate the effectiveness of the proposed control scheme.     

Adaptive finite-time stabilisation of high-order uncertain nonlinear systems

This paper studies the problem of finite-time stabilisation of more general high-order nonlinear systems with dynamic and parametric uncertainties. By characterising the unmeasured dynamic uncertainty with finite-time input-to-state stability (FTISS), skillfully combining Lyapunov function, sign function, backstepping, adaptive control and FTISS approaches, and using finite-time stability theory, an adaptive state feedback controller is designed to guarantee high-order uncertain nonlinear systems globally finite-time stable.     

Distributed prescribed performance control for consensus output tracking of nonlinear semi-strict feedback systems using finite-time disturbance observers

The distributed consensus output tracking problem is dealt with for a class of nonlinear semi-strict feedback systems in the presence of mismatched nonlinear uncertainties, external disturbances and uncertain nonlinear virtual control coefficients of the subsystems. The systems are under a directed communication graph, where the leader node is the root. The controller is designed in a backstepping manner, and the dynamic surface technique is adopted to avoid direct differentiation. At each step of virtual controller design, a prescribed performance controller is constructed to achieve prescribed transient performance so that the system states remain in the feasible domain. Then each virtual controller is enhanced by a finite-time disturbance observer which estimates the disturbance term in a finite-time. The properties of the control system are analysed theoretically. It is clarified that the prescribed performance control technique ensures that the system signals stay in the feasible domain, whereas sufficiently small ultimate control errors can be achieved by the finite-time disturbance observers. Finally, the performance of the proposed methods is confirmed by numerical studies.