无人飞艇的鲁棒航向控制系统设计

将线性矩阵不等式(LMI)方法应用于静不稳定飞艇的鲁棒航向控制系统设计中,该飞艇模型具有参数不确定性。首先,给出了飞艇的横侧向运动模型。并且,采用了多面体集合的形式来描述对象的不确定性。然后采用LMI方法,将飞艇航向控制系统的设计简化为一个基于多面体系统的凸优化问题。由于该方法存在着一些设计裕度, 因此可以利用这种裕度来实现多目标控制。根据该方法设计出的闭环控制系统由内环的增稳系统和外环的PI控制器组成。最后,提供并分析了飞艇航向控制系统的仿真结果。     

连续时间多面体不确定系统的鲁棒预测控制

运用线性矩阵不等式方法,研究连续时间多面体不确定系统的鲁棒预测控制问题。通过在线求解无穷时域二次型性能指标下的"最小-最大"优化问题,给出了分段连续的状态反馈控制器存在的充分条件。运用可控不变集理论,解决在线优化问题的可行性,证明了初始时刻的可行解可以保证闭环系统渐近稳定。仿真证明了控制算法的有效性。     

Robust model predictive control of continuous uncertain systems*

The authors concern robust model predictive control for linear continuous systems with polytopic uncertainties and input constraints. At each sampling time, a piecewise constant control sequence is obtained by solving a set of linear matrix inequalities. The sufficient conditions on the existence of the model predictive control are given, and the robust stability of the closed-loop systems is guaranteed. A simulation example illustrates the efficiency of the proposed method.     

一类多状态时滞不确定系统的鲁棒预测控制

针对一类多状态时滞多面体不确定对象,提出了一种鲁棒预测控制算法。基于参数相关的李亚普诺夫函数,给出了系统稳定的充分条件。通过求解满足若干线性矩阵不等式条件的上界值的最优化问题,获得了约束范围内满足系统鲁棒性能的最优控制律。优化问题的可行性保证了算法的鲁棒稳定性。仿真实例证明了该算法的有效性。     

Controlling uncertain fuzzy neutral dynamic systems with Markov jumps

The robust H∞ control problems for stochastic fuzzy neutral Markov jump systems (MJSs) with parameters uncertainties and multiple time-delays are considered. The delays are respectively considered as constant and time varying, and the uncertain parameters are assumed to be norm bounded. By means of Takagi-Sugeno fuzzy models, the overall closed-loop fuzzy dynamics are constructed through selected membership functions. By selecting the appropriate Lyapunov-Krasovskii functions, the sufficient condition is given such that the uncertain fuzzy neutral MJSs are stochastically stability for all admissible uncertainties and satisfies the given H∞ control index. The stability and H∞ control criteria are formulated in the form of linear matrix inequalities, which can be easily checked in practice. Practical examples illustrate the effectiveness of the developed techniques.     

Integral sliding mode control of time-delay systems with mismatching uncertainties

A linear matrix inequality (LMI)-based sliding surface design method for integral sliding mode control of uncertain timedelay systems with mismatching uncertainties is proposed.The uncertain time-delay system under consideration may have mismatching norm bounded uncertainties in the state matrix as well as the input matrix.A sufficient condition for the existence of a sliding surface is given to guarantee asymptotic stability of the full order sliding mode dynamics.An LMI characterization of the sliding surface is given,together with an integral sliding mode control law guaranteeing the existence of a sliding mode from the initial time.Finally,a simulation is given to show the effectiveness of the proposed method.     

Observer-based robust predictive control of singular systems with time-delay and parameter uncertainties

The problem of observer-based robust predictive control is studied for the singular systems with norm-bounded uncertainties and time-delay, and the design method of robust predictive observer-based controller is proposed. By constructing the Lyapunov function with the error terms, the infinite time domain "min-max"optimization problems are converted into convex optimization problems solving by the linear matrix inequality (LMI), and the sufficient conditions for the existence of this control are derived. It is proved that the robust stability of the closed-loop singular systems can be guaranteed by the initial feasible solutions of the optimization problems, and the regular and the impulse-free of the singular systems are also guaranteed. A simulation example illustrates the efficiency of this method.     

一类不确定时滞系统的滑模控制

考虑了一类同时存在状态不确定性和控制不确定性的时滞系统的滑模控制问题,通过采用李亚普诺夫方法和线性矩阵不等式(LMI)技术,给出了闭环系统渐近稳定的充分条件,而且滑模控制律和滑模面的设计可以利用线性矩阵不等式的解得到,证明了该滑模控制律能保证状态轨迹被驱动到指定的切换面上。仿真实验表明了算法的有效性。     

Polytopic LPV modeling and gain-scheduled switching control for a flexible air-breathing hypersonic vehicle

A novel gain-scheduled switching control method for the longitudinal motion of a flexible air-breathing hypersonic vehicle (FAHV) is proposed.Firstly,velocity and altitude are selected as scheduling variables,a polytopic linear parameter varying(LPV) model is developed to represent the complex nonlinear longitudinal dynamics of the FAHV.Secondly,based on the obtained polytopic LPV model,the flight envelope is divided into four smaller subregions, and four gain-scheduled controllers are designed for these parameter subregions.Then,by the defined switching characteristic function,these gain-scheduled controllers are switched in order to guarantee the closed-loop FAHV system to be asymptotically stable and satisfy a given tracking error performance criterion.The condition of gain-scheduled switching controller synthesis is given in terms of linear matrix inequalities(LMIs) which can be easily solved by using standard software packages.Finally,simulation results show the effectiveness of the presented method.     

线性不确定系统的鲁棒容错H∞控制设计

研究了线性不确定系统的鲁棒容错H∞控制问题.当系统既有状态滞后,又有控制输入滞后,而且状态和控制输入的不确定项均满足匹配条件时,运用线性矩阵不等式(LMI)方法,提出了一种针对不确定系统的鲁棒容错反馈控制设计方法.利用该方法设计的闭环系统,不仅在传感器发生故障时具有完整性,而且对于系统的参数不确定性具有鲁棒性.以设计实例及仿真结果验证了这种方法的有效性.     

具有饱和执行器跳变系统的鲁棒模型预测控制

针对一类具有饱和执行器的不确定离散Markov跳变系统,提出鲁棒模型预测控制器设计方法。为便于工程应用,考虑被控跳变系统各模态下的动态系统参数以及各模态间的跳变转移模态均存在不确定性的情形,这些不确定性均以凸多面体的形式给出。预测控制器的求解通过在每一个采样时刻优化无穷时域的最坏二次性能指标实现,该预测控制序列在每个采样时刻表现为具有饱和特性的状态反馈控制律,从而使得所形成的闭环系统鲁棒均方稳定。为方便求解,将控制器的求解转化为以线性矩阵不等式形式给出的正半定规划(SDP)问题。数值示例验证了所提方法的有效性。     

不确定广义系统的保成本可靠控制

对一类含有时变范数有界参数不确定广义系统和部分执行器可能失效的系统,结合一个二次型性能指标,研究了使得闭环系统保持正则、无脉冲和稳定,且闭环性能指标值不超过某个确定界的保成本可靠控制律的设计问题。通过矩阵不等式导出保成本可靠控制律的一个充分存在条件,进而用线性矩阵不等式给出了保成本可靠控制器的一个参数化的表示。在此基础上,通过建立并求解一个凸优化问题,给出了最优保成本可靠控制律的设计方法。最后,通过例子对所得结论加以说明。     

含有跳变参数的中立系统的鲁棒保性能滤波

对一类含有马尔可夫跳变参数的中立系统研究了鲁棒保性能滤波问题。系统中含有时滞，跳变参数与不确定性。系统中的跳变参数可以通过有限状态马尔可夫过程来描述。目标是设计无记忆线性滤波器使得对所有的不确定性增广系统是时滞独立鲁棒随机稳定的，并且满足所提的保性能指标。基于随机微分方程稳定性理论，给出了线性滤波器存在的充分条件。借助一组相互关联的线性矩阵不等式，获得了鲁棒保性能的设计方法。通过求解线性矩阵不等式约束下的凸优化问题，给出了次优保性能滤波器的设计方法。     

不确定关联时滞大系统鲁棒可靠控制设计方法

针对一类具有状态时滞和参数不确定性的不确定关联时滞大系统 ,提出了一种基于状态观测器的鲁棒可靠控制器设计方法。该方法通过求解一组线性矩阵不等式 (LMI) ,给出状态观测器和线性动态输出反馈控制器的设计方法。该控制器对于系统中任意容许的不确定性以及在每一个子系统中预先指定的执行器子集合执行器的失效 ,都可以镇定相应的闭环系统。通过仿真实验证明该设计方法的有效性。     

Robust Stability Analysis for Linear Time-delay Systemswith Uncertain Parameters: LMI Approach

1IntroductionDuringthepastfewyears,therobuststabilityproblemoflineartime-delaysystemssubjecttoperturbationshasbeentreatedextensivelyintheliterature.Asaresult,explicitboundsforbothstructuredandunstructuredperturbationshavebeenderived(seeCheresetal.,1991;LuoandVanDenBosch,1997;ninhandAldeen1995;andthereferencestherein).However,inthoseresults,someparametersmustbefirstdeterminedtoobtaintheboundsontheallowableperturbations.Ingeneral,differentselectionapproachesfortheparametersmayresultindifferen…     

On delay-dependent robust stability for uncertain neutral systems

1.INTRODUCTION Time delaysarefrequentlyencounteredinvariousengi neeringsystems,includingaircraftstabilization,nuclear reactors,populationdynamicsmodels[1].Theirexistence isoftenthesourceofinstabilityinmanycontrolsystems.Stabilitycriteriafortime delaysystemscanbeclassified intotwocategories.Thestabilitycriteriathatincludein formationonthesizeofdelaysarereferredtoasdelay de pendentcriteria[2～18]andthecriteriaapplicabletoanar bitrarysizeofdelaysarereferredtoasdelay independent criteria[19～…     

不确定广义系统的鲁棒H2控制

利用线性矩阵不等式 (LMI)方法 ,研究范数有界的不确定广义系统的鲁棒H2 性能分析与控制问题。对该系统所有容许的不确定参数 ,提出了满足鲁棒H2 次优性能的一个线性矩阵不等式 (LMI)的充分条件。进而设计了一个状态反馈控制律 ,保证了闭环系统是容许的且满足鲁棒H2 次优性能 ,即闭环传递函数的H2 范数小于一个给定的正数。利用Matlab控制工具箱 ,给出了该控制律的LMI实用设计方法。最后的数值例子进一步说明了所取得的主要结果     

Sampling Dependent Stability Results for Aperiodic Sampled-Data Systems

This paper investigates sampling dependent stability for aperiodic sampled-data systems by employing a Lyapunov-like functional that is time-dependent, and not imposed to be definite positive.Based on the system information on the sampling interval wholly rather than partly, a new Lyapunovlike functional is constructed, which extends existing ones by introducing the integral of the system state and the cross terms among this integral and the sampled state. To take advantage of the integral of the system state, integral equations of the sampled-data system are explored when estimating the derivative of the extended functional. By the Lyapunov-like functional theory, a new sampling dependent stability result is obtained for sampled-data systems without uncertainties. Then, the stability result is applied to sampled-data systems with polytopic uncertainties and a robust stability result is derived. At last,numerical examples are given to illustrate that the stability results improve over some existing ones.     

不确定离散时滞控制饱和系统L2增益分析设计

针对离散时间不确定含时滞和控制饱和系统的镇定和干扰抑制问题,提出了状态反馈和抗饱和动态输出反馈方法。该方法利用Lyapunov函数可获得时滞相关的线性矩阵不等式。线性矩阵不等式条件可保证不确定闭环系统的无干扰时鲁棒内稳定性和在某椭球内预先给定的有干扰时L2性能水平。通过把状态反馈增益视为一自由参数,利用所得到的优化问题给出了控制器设计的具体步骤,通过仿真算例证明该方法的有效性。