观测器基于自适应滑模控制的半马尔科夫跳变系统

在许多工业系统中都存在时滞的现象,会使得系统控制性能降低,影响系统的稳定,在实际系统中,滑模依赖时变时滞更值得研究,而滑模控制对于外界干扰,非线性和参数不确定具有很好的鲁棒性,并且控制结构简单,视如上情况,针对观测器基于滑模控制的Markov切换系统,设计积分滑模面,并通过估计变量得到误差系统,通过解线性矩阵不等式使得...     

新型有限时间收敛滑模扩张状态观测器研究

针对一类具有量测噪声的非线性不确定系统,设计了基于新型滑模扩张状态观测器的Terminal滑模控制方案．首先对系统进行两次状态扩张,然后设计一种新型滑模扩张状态观测器,通过采用特殊的滑模面保证观测误差在有限时间内收敛到零．在此基础上,设计Terminal滑模控制器,使系统状态也能在有限时间内收敛到零．严格的理论证明和仿真结果均证明了所设计新型滑模观测器及闭环控制方案的有效性和快速性．     

计及随机传感器时滞的不确定半Markov跳变系统鲁棒滑模控制

在实际系统中,系统参数与结构随机变化、未知外界干扰、传感器时滞等现象时有发生并严重影响了系统的稳定运行.为了解决这一问题,本文提出计及随机传感器时滞的一类不确定半Markov跳变系统鲁棒滑模控制方法,其中系统的传感器时滞通过使用Bernoulli随机分布进行描述.考虑系统状态信息不可测量条件下,文章设计模态依赖Luenberger观测器去估计半Markov跳变系统的运行状态.然后,本文构造一个积分滑模面并借助随机Lyapunov理论,提出两种半Markov跳变系统的随机稳定性分析方法.进而,文章提出基于观测器的滑模控制方法使得系统状态能够在有限时间内到达滑模面上以及滑模动态在H_∞性能指标γ下是随机稳定的.最后,通过一种基于他励直流电动机模型的数值仿真例子验证所设计的滑模控制方法的有效性与正确性.     

自适应比例–积分H2滑模观测器设计

传统的龙伯格观测器的观测精度极易受到未知外部扰动的影响.为了解决这个问题,本文设计了一种基于径向基神经网络的自适应比例–积分H₂滑模观测器,实现了参数不确定性和外部扰动下非线性系统的鲁棒确切估计.首先,利用径向基神经网络自适应逼近系统模型的复杂非线性项;其次,设计基于误差的线性滑模面,将比例–积分滑模项注入观测器中,使得滑模动态在有限时间内收敛于滑模面,实现对外部扰动和系统模型非线性的完全补偿;最后,基于H₂次优控制和区域极点配置,提出观测器参数自整定方法.通过对单连杆机器人的仿真结果表明,该方法能够保证非线性系统具有较好的鲁棒性和自适应性.     

基于观测器的滑模控制非线性中立型时滞系统

针对一类状态不可测的非线性不确定中立型时滞系统,基于滑模控制理论,采用线性矩阵不等式的处理方法,提出了滑动模态鲁棒渐近稳定时滞相关的充分条件,设计了一类滑模观测器,同时给出了该观测器存在的充分条件;然后应用滑模控制的趋近率方法和基于观测器所得到的系统估计状态,综合了一类滑模控制器,该控制器同时保证了估计状态下滑模面和估计误差状态下滑模面的渐近可达性;最后通过数值实例证明了该控制方案的可行性.     

滑模控制一类非线性分布式时滞系统

针对一类状态不可测的非线性不确定分布式时滞系统, 给出了系统滑动模态鲁棒渐近稳定的充分条件. 设计了一类滑模观测器, 同时采用线性矩阵不等式的处理方法给出了该观测器存在的充分条件. 再应用滑模控制的趋近率方法和基于观测器所得到的估计状态, 综合了一类滑模控制器. 该控制器同时保证了估计状态下的滑模面和估计误差状态下的滑模面的渐近可达性.     

分数布朗运动干扰下广义随机系统滑模控制

本文考虑分数布朗运动干扰下时滞广义随机系统的基于观测器的滑模控制.首先设计了不受分数布朗运动干扰的状态观测器,然后给出了基于观测器的积分型滑模面函数的定义.为了研究观测器系统有限时间随机有界性,构造了带有二重积分的新型Lyapunov函数来处理分数布朗运动.利用奇异值分解原理,解决了观测器增益矩阵设计问题.利用线性矩阵...     

不确定非线性时滞系统的鲁棒可靠控制

研究一类包含状态时滞的未知非线性扰动项和参数不确定性的不确定时滞系统基于状态观测器的鲁棒可靠控制问题。其中非线性满足范数有界条件,参数不确定性是时变的。目的是设计状态观测器和线性无记忆观测状态反馈控制器,使得对于任意容许的不确定性以及在系统中预先指定的执行器子集合的执行器的失效,相应的闭环系统渐近稳定。最后给出一个数值例子验证了所得结果的有效性。     

具有分布时滞线性系统的滑模控制与仿真

研究时滞控制系统稳定性优化问题,针对一类含有分布时滞和离散时滞的线性系统,对于解决延时问题,提高控制系统的稳定性能,有重要的理论意义和实际应用价值.根据分布时滞的特殊形式特点,构造了Lyapunov泛函,利用稳定性理论、矩阵不等式分析技巧及积分不等式技术,采用线性矩阵不等式形式的结论.选取了滑模面,构造了滑模控制器,使得系统满足滑模到达条件.可通过构造适当的Lyapunov泛函,利用虚拟反馈控制,采用状态反馈的极点配置方法,给出了闭环系统渐近稳定的充分条件.方法设计了时滞独立的滑模面,并简化了滑模控制器的设计.进行仿真,结果说明了滑模控制能确保时滞系统的稳定性,并验证了方法的有效性.     

时滞系统的状态反馈和基于观测器的输出反馈设计

考虑了同时具有状态和输入时滞线性定常系统的H∞镇定问题.基于动态耗散理论和微分对策原理,通过采用带积分项的储存函数,对系统的状态反馈控制器和基于观测器的输出反馈设计问题进行了处理.它们的可解充分条件可以化为与时滞相关的矩阵不等式和Riccati方程的形式.得到的与时滞相关的状态反馈控制律和基于观测器的输出反馈控制律都能使闭环系统内稳且具有H∞干扰衰减.     

基于扰动观测器补偿的机械臂非奇异快速终端滑模控制

针对机械臂系统在实际应用中存在的建模误差及未知扰动问题, 设计了一种基于扰动观测器的改进型非 奇异快速终端滑模控制策略. 通过扰动观测器准确估计系统存在的总扰动, 并设计恰当的非线性增益函数使扰动观 测误差指数收敛, 实现了对控制器的前馈补偿. 考虑到终端滑模存在的奇异性问题, 结合扰动观测器设计了非奇异 快速终端滑模控制器, 在保证跟踪误差有限时间收敛的同时抑制了滑模控制固有的抖振现象. 同时在控制器设计过 程中, 用fal函数代替sig函数有利于削弱滑模控制抖振, 提高系统稳定性及跟踪精度. 最后, 利用MATLAB软件进行 实验仿真, 验证了所设计控制器的有效性.     

Robust reduced-order sliding mode observer design

In this article, a triple state and output variable transformation-based method combined with linear matrix inequality (LMI) techniques to design a new robust reduced-order sliding mode observer for perturbed linear multiple-input and multiple-output systems is developed. The state and output variables of the original system are triple transformed into suitable canonical form coordinates to facilitate the design of a reduced-order observer. The existing transformations are summarised in this study and presented systematically. A new combined observer configuration is proposed and compared with another type of observers. Global asymptotical stability LMI and sliding mode existence conditions for the coupled observer error system are derived using Lyapunov full quadratic form. Reaching and sliding modes of motion of decoupled observer error system are discussed as well. Two numerical and simulation examples are given to illustrate the usefulness of the proposed design techniques.     

Functional observer-based sliding mode control for linear discrete-time-delayed stochastic systems

Functional observers are the primary solution to sundry estimation problems, wherein full- or reduced-order observer cannot be directly applied. This paper presents a functional observer-based sliding mode control method for the linear discrete-time delayed stochastic system. Stability analysis of sliding function is presented for the delayed stochastic system with a linear matrix inequality approach. The functional observer method for the linear discrete-time-delayed stochastic system is proposed based on the Kronecker product approach. Sliding mode controller is estimated using the functional observer method. Finally, to demonstrate the efficacy of the proposed design, comparison of its performance with some of the well-known existing state feedback controller is presented.     

Decentralized Observer Design for a Class of Nonlinear Uncertain Large Scale Systems with Lumped Perturbations

Many valuable properties of the state feedback method can not be applied to some class of control systems while some of the system states cannot be measured directly. An attractive alternative approach is to make good use of a state observer. In this paper, a new decentralized sliding mode observer (DSMO) is proposed for a class of nonlinear uncertain large‐scale systems (LSS) with lumped perturbations based on the sliding mode control (SMC) theory. Our main result presented here is that we introduce a new switching term to the traditional LSS observer design for a class of large‐scale system to generate a new decentralized sliding mode observer. The generalized matrix inverse concept is adopted to avoid using the un‐measurable state and the global reaching condition of the sliding mode for each error subsystem is guaranteed. The stability of each equivalent error subsystem is verified based on the strictly positive real concept. It also shows that the investigated uncertain large‐scale systems still possesses the property of insensitivity to the lumped perturbations as does the traditional linear system. Moreover, the state transformation approach is no longer needed as there is no longer concern about the problems of finding a suitable transformation or indirect estimated states, since the proposed DSMO is not based on the transformed system model. Finally, a numerical example with a series of computer simulations is given to demonstrate the validity of the proposed decentralized sliding mode observer.     

Robotic Manipulators State Observation Via One-Time Gain Switching

High-gain Luenberger-like state observation would provide the best possible tracking error of nonlinear systems at the expense of higher transient variance and slower convergence to the real state. Conversely, low-gain Luenberger-like observation usually provides lower transient variance of the error system, but might lead to nonzero or nonconvergent steady tracking error. This paper presents new switching-gain observer designs that capitalize on the benefits of low-gain, high-gain, and sliding mode observations. Switching and non-switching observer designs are both considered. Since adaptive observers are often of complex structures and might be difficult to implement, a simpler adaptation form is presented using one-time switching between two predetermined solutions. A nonlinear coordinate transformation is applied to obtain a linear observable system with nonlinear perturbation terms characterized by a Lipschitz constant and/or a finite bound on the norm. Sufficient conditions are derived for the existence of sliding mode, asymptotic stability of the error system, and the independence of the reconstruction error system from the perturbation inputs during the sliding mode. The new observer designs are applied to flexible-joint manipulators in order to explore their performance capabilities. The switching-gain observer was shown to be a reasonable compromise that is easy to be implemented.     

基于扩张状态观测器的二质量系统非奇异快速终端滑模控制

针对含未知负载信息的二质量伺服系统,提出一种基于有限时间扩张状态观测器的非奇异快速终端滑模控制方法.首先,利用电机侧位置信息设计有限时间扩张状态观测器估计系统的扰动,并将估计值融入到控制器中作为前馈项对系统的未知扰动进行补偿;然后,引入一种新型的滑模趋近律,该趋近律能够避免传统滑模控制中存在的奇异性问题,据此设计非奇异快速终端滑模控制器,保证系统状态在有限时间内收敛到原点,并根据李雅普诺夫稳定性理论分析闭环系统的稳定性;最后,通过仿真和实验验证所提出方法的优越性.结果表明,与传统的PID等控制相比较,所提出的基于扩张状态观测器的有限时间滑模控制方法能够提高系统的跟踪性能,并有效增强二质量伺服系统的抗扰动能力.     

基于三阶超螺旋滑模观测器算法的机器人力矩估计方法

本文研究了六自由度(6-DOF)机器人关节力矩估计问题.为了提高机器人关节力矩估计精度,本文设计了一种三阶超螺旋滑模关节力矩观测器.在对观测器系统进行稳定性分析时,本文设计了一种新的Lyapunov函数证明了观测器闭环系统的稳定性.与已有的机器人力矩观测器结果不同,该力矩观测器仅以机器人关节角度作为观测器输入信号,减少了对机器人系统信息的依赖.最后,以6-DOF工业机器人为对象,开展实验验证.实验结果表明,与传统线性力矩观测器相比,本文提出的滑模力矩观测器估计误差小,验证理论的正确性.     

Nonfragile observer‐based H ∞ sliding mode control for Itô stochastic systems with Markovian switching

The paper is devoted to investigating sliding mode control for a class of nonlinear uncertain stochastic systems with input nonlinearity and Markovian switching. A nonfragile observer subjected to the transition rates of the modes is designed. By some specified matrices, the connections among the designed sliding surfaces corresponding to every mode are established. The state estimation‐based sliding mode control law is derived to guarantee the reachability of the sliding surface in finite time interval. The sufficient conditions on asymptotically stochastic stability of the error system and sliding mode dynamics with a given disturbance attenuation level are derived in terms of linear matrix inequalities. Finally, an example is provided to illustrate the efficiency of the proposed method. Copyright © 2013 John Wiley & Sons, Ltd.