一种反向递推正弦干扰观测器的设计方法

在多源干扰环境下,考虑一种基于输出信号的正弦干扰估计方法.引入低通滤波器激励干扰特性,得到一组级联关系的不可测信号,并将其分解为标准正弦虚拟干扰、等价有界干扰以及衰减项;在频率已知条件下,设计辅助滤波器,建立干扰频率与虚拟干扰之间关系,从而将外部正弦扰动表示为关于虚拟干扰的参数形式,利用虚拟干扰的估计值逐次降阶反推输入...     

基于降维观测器的非最小相位系统的快速故障估计

针对传统的基于自适应观测器的故障诊断方法不适用于非最小相位系统的问题,本文基于降维 观测器提出了一种新的自适应故障估计方法．首先引入特殊坐标基（special coordinate basis, SCB）变换,可以 方便地求出误差系统的不变零点．其次对于变换之后的系统,基于降维观测器提出了一种新的快速故障估计 方法,目的在于提高故障估计的性能,即故障估计的快速性和准确性．最后仿真验证了此方法的有效性．     

非方广义系统的未知输入有限时间观测器设计

研究了含未知输入的非方广义系统的有限时间输入解耦观测器设计问题,在一定条件下基于非方广义系统的结构特征,引入一个输入-状态对的非奇异转换,把含未知输入的非方广义系统等价地转化为输入已知的正常状态空间系统．用传统的设计正常状态空间系统观测器的方法去构造含未知输入的非方广义系统的未知输入观测器,并给出了观测器存在的充分条件,由此得出了有限时间观测器的设计步骤．     

一类非最小相位系统的智能控制

针对具有右半复平面零点的非最小相位系统,设计了一种模糊PID控制器,并且用伪并行遗传算法对其参数进行寻优.仿真结果表明,本文设计的基于遗传算法的模糊PID控制器对于具有右半复平面零点非最小相位系统具有很好的跟踪性,能够同时减小负调、超调,缩短上升时间.     

一类非最小相位系统的PID控制器整定方法

针对非最小相位对象,提出了一种比例—积分—微分(PID)控制器的整定方法.将含有右半复平面零点的非最小相位系统近似拟合为一个稳定的大滞后系统,应用一种专门针对大滞后系统的PID参数两步整定方法可以对系统PID参数进行粗调,然后通过调整比例系数α,便可以成功地设置其PID控制器参数,达到抑制非最小相位时滞和负调的作用.仿真实验证明了两步整定方法的有效性和鲁棒性.     

一类非最小相位非线性系统的自适应控制

针对一类非最小相位的非线性系统,通过引入一个近似系统,提出了一种简单的间接自适应控制方法,并分析了采用该方法后系统输出的跟踪性能,给出了输出跟踪误差的上限.该方法可克服现有的非线性自适应控制方法只能控制最小相位的非线性系统并且容易产生过度控制的缺点.     

同时含有未知输入和测量干扰系统全维和降维观测器设计

针对同时含有未知输入和测量干扰的不确定系统研究了全维和降维观测器设计问题. 首先, 利用待定系数法给出了全维观测器的结构和存在条件. 该条件完全由原系统的系统矩阵给出, 易于检验. 对于降维观测器, 为了消除测量干扰的影响, 提出了一种新的测量输出构造方法, 使得新构造的测量输出不再包含干扰信号. 此外, 证明了全维和降维观测器存在条件的内在统一性, 即全维观测器所需要满足的观测器匹配条件和强可检测条件在研究降维观测器所要讨论的新的系统中都可以得到保持. 因而, 在全维观测器存在条件下, 也可以设计一个相应的降维观测器. 最后, 给出了一个数值例子验证所提方法的有效性.     

一类非最小相位非线性系统的直接自适应控制

一类非最小相位非线性系统的直接自适应控制韩存武,袁少强,马晓军,文传源（北京航空航天大学自控系北京１０００８３）关键词：非线性系统,自适应控制,非最小相位系统．１引言非线性系统的自适应控制作为当前自动控制领域最富有挑战性、同时也最困难的前沿课题之一越...     

二阶智能体的分布式非光滑资源分配算法

分布式资源分配问题旨在满足局部约束下完成一定量资源分配的同时使全局成本函数最小.首先,针对无向连通网络下二阶积分器型线性智能体系统,结合Karush-Kuhn-Tucker条件,提出一种初始值任意的分布式优化算法,其中,全局等式约束对偶变量实现比例积分控制,局部凸函数不等式约束对偶变量实现自动获取.当全局成本函数为非光滑凸函数时,借助集值LaSalle不变性原理理论证明所提出算法渐近收敛到全局最优解.其次,将所提出算法推广至无向连通网络下参数未知的Euler-Lagrange多智能体系统.当全局成本函数为非光滑凸函数时,借助Barbalat引理理论证明所提出算法渐近收敛到全局最优解.最后,通过数值仿真验证了所提算法的有效性.     

一类含输入时滞非线性系统的干扰观测器控制

基于干扰观测器控制（Disturbance-observer-based control,DOBC）作为一种有效的干扰补偿策略取得了广泛的应用. 然而,当干扰和控制输入不能在同一时刻进入控制通道时,外部信号很难得到实时估计和补偿.提出一种复合DOBC结构,包括干扰观测、干扰预测和反馈调节三个部分.该方法的特点是即使一类非线性系统存在输入时滞,同样可以继承传统DOBC的优点. 最后,通过构造辅助观测器给出了预测误差以及复合闭环系统的稳定性分析方法.     

Global compensation of unknown sinusoidal disturbances for a class of nonlinear nonminimum phase systems

A class of output feedback stabilizable nonlinear systems with known output dependent nonlinearities and affected by unknown sinusoidal disturbances is considered: Nonminimum phase systems are also allowed. The problem of designing a global output feedback compensator which drives the state of the system exponentially to zero is solved when the disturbance consists of a known number of biased sinusoids with any unknown bias, magnitudes, phases, and frequencies.     

Adaptive observer of an unknown sinusoidal output disturbance for linear plants

A new algorithm is proposed to the design of an adaptive observer for an unknown sinusoidal disturbance that affects the output of a non-minimum phase linear control plant.     

Observer design for a class of MIMO nonlinear systems

A simple observer is proposed for a large class of MIMO nonlinear systems which includes many physical models. The main characteristic of the proposed observer lies in the easiness of its implementation and calibration. Indeed, the gain of this observer does not necessitate the resolution of any dynamical system and its expression is given. Moreover, its calibration is achieved through the choice of a single parameter. A simulation example is given in order to illustrate the performance of the proposed observer.     

一类非线性切换系统的观测器设计

研究了一类切换规则为时间依赖型的非线性切换系统的观测器设计问题．分别在切换序列已知与平均驻留时间已知的情况下利用线性矩阵不等式（LMI）给出了非线性项满足Lipschitz条件的切换系统的观测器增益求解方法,并给出了观测器设计步骤．最后给出仿真算例说明了本文方法的有效性．     

Crossover frequency limitations in MIMO nonminimum phase feedback systems

This paper investigates limitations and design tradeoffs of the closed-loop sensitivity/performance of linear-time-invariant nonminimum-phase uncertain multiple-input-multiple-output plants, with I inputs and m outputs, where m /spl les/ l. It is shown that if rows i/sub 1/...,i/sub k/ of the plant transfer function form a k /spl times/ l nonminimum phase transfer matrix, and if the design is such that the sensitivity gain of k - 1 rows among the rows i/sub 1/,...,i/sub k/ of the closed-loop transfer function is low, then by necessity the sensitivity gain of the remaining row is high. This sensitivity constraint is quantified with the help of the crossover frequency restriction of a specially constructed single-input-single-output transfer function that includes the right half plane zeros and poles of the k /spl times/ l transfer matrix.     

Observer design for discrete systems with unknown exogenous inputs

A design procedure is developed for determining optimal discrete observers for estimating system states and unknown exogenous system inputs. This procedure is based on augmenting a standard system observer with an input model. The augmented model is then transformed into the discrete z-domain to determine relevant input/output transfer function matrices. The transfer function matrices are used to develop transfer function relationships between unknown exogenous inputs and the observer estimate of these inputs. It is shown that the optimal observer gains can be determined by implementing the observer as a Fisher filter. An example of the procedure is demonstrated with a third-order point-mass tracking filter     

Adaptive algorithms for the rejection of sinusoidal disturbances with unknown frequency

Two algorithms are presented for the rejection of sinusoidal disturbances with unknown frequency. The first is an indirect algorithm where the frequency of the disturbance is estimated, and the estimate is used in another adaptive algorithm that adjusts the magnitude and phase of the input needed to cancel the effect of the disturbance. A direct algorithm that uses the concept of a phase-locked loop is also presented in which frequency estimation and disturbance cancellation are performed simultaneously. Approximate analyses are presented for both schemes and the results are found useful for the selection of the design parameters. Simulations are given which demonstrate the validity of the analytical results and the ability of the algorithms to reject sinusoidal disturbances with unknown frequency. The indirect algorithm is found to have a larger capture region for the parameter estimates, whereas the direct algorithm has superior convergence properties locally about the optimum parameter estimates     

Observer design for a class of multi-input multi-output nonlinear systems

In this article, the problem of state observer design for a class of multi-input multi-output nonlinear systems is considered. Via state transformation and the constructive use of a Lyapunov function, the new observer design approach is addressed by introducing a parameter ? in the observer. Some sufficient conditions are given which guarantee the estimation error to asymptotically converge to zero under adaptive conditions. An example is included to illustrate the method.     

Dynamic output feedback sliding mode control for nonminimum phase linear systems with disturbance attenuation

A sliding mode control algorithm using output information only is developed in this paper for a linear system with mismatched disturbance. The nominal system is allowed to be nonminimum phase. A scheme designed to combine the output‐dependent integral sliding surface with a reduced‐order observer is proposed. Utilizing an H_∞ control analytical technique, once the system is in the sliding mode, the proposed algorithm can guarantee robust stabilization and sustain the nature of performing disturbance attenuation when the solution to one algebraic Riccati inequality can be found. A controller is designed to satisfy the reaching and sliding condition in line with the reduced‐order observer. Finally, a numerical example is explained to show the applicability of the proposed scheme. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society