LMI方法非脆弱鲁棒H∞控制器设计

研究了控制器增益在加法式摄动下的非脆弱鲁棒H∞控制问题,基于线性矩阵不等式(LMI)理论,提出了非脆弱鲁棒H∞控制器存在的充分条件,将具有控制器增益不确定性的非脆弱鲁棒控制器设计问题,化为具有线性矩阵不等式约束和线性目标函数的凸优化问题求解,得到了一种非脆弱鲁棒H∞状态反馈控制器的简化设计方法.所设计的控制器在容许的增益摄动下,仍能保证闭环系统的稳定性和性能要求,系统不仅具有鲁棒性而且是非脆弱的,从而使系统具有更高的可靠性.仿真结果表明了设计方法的有效性.     

时滞依赖型区间时滞系统非脆弱H_∞控制

针对一类状态和控制输入矩阵均为区间矩阵的不确定时滞系统,其中状态和控制输入同时具有未知但有上界的时间滞后,基于Lyapunov稳定性理论,利用线性矩阵不等式(LMI)方法,讨论了该类时滞系统的时滞依赖型非脆弱H∞状态反馈控制器设计问题.在区间不确定性和控制器执行机构扰动均满足增益有界条件下,得到了该类时滞系统的满足H∞性能的一个充分条件.通过求解一个线性矩阵不等式(LMIs)组,即可获得鲁棒H∞控制器.最后对某型飞机作机动飞行仿真,仿真结果表明该鲁棒控制器设计方法是有效的.     

参数不确定的单时滞系统基于简化的L-K泛函的稳定性分析

参数不确定和时滞广泛存在于各种实际的控制系统中,而且它们往往是导致系统不稳定或性能下降的原因。本文基于Lyapunov稳定性理论,通过构造简化的Lyapunov-Krasovskii泛函,同时应用线性矩阵不等式(LMI:linearmatrix inequality)方法,研究了参数不确定和单时变时滞系统的鲁棒稳定性问题,并导出了由LMI表示的该类系统的鲁棒稳定性判据,而且,通过这类简化的L-K泛函,在充分利用时滞信息的基础上减少了判据的保守性。最后借助含不确定性扰动的具有单时变时滞的单机-无穷大系统模型,分析了保持鲁棒稳定时系统可承受的最大时滞的界限,数值仿真验证了方法的有效性。     

一类时延网络控制系统的最优非脆弱H∞控制

针对一类时延网络控制系统,研究了当存在有限能量外部扰动时,系统的最优状态反馈非脆弱H_∞控制律的设计问题。通过将时延看作系统的时变参数不确定性,应用H_∞鲁棒控制理论及线性矩阵不等式(LMI)技巧,给出了具有控制增益扰动的次优非脆弱H_∞控制律存在的充分条件,提出了最优非脆弱H_∞控制律的设计方法。数值仿真例子表明了所提方法的有效性。     

基于迭代域性能函数的非脆弱保性迭代学习控制

研究了离散线性系统非脆弱保性能迭代学习控制及其优化问题.针对离散线性系统,首先根据迭代域二次型性能函数,将迭代学习问题转化为非齐次LQ问题,再选取适当的Lyapunov函数,基于线性矩阵不等式方法,针对控制器具有加法不确定性和乘法不确定两种情况,给出了非脆弱保性能迭代学习控制器的设计方法及其优化方法.最后以一个数值例子说明了上述方法的有效性.     

一类线性不确定切换系统的非脆弱控制器设计

针对一类线性不确定切换系统,利用公共Lyapunov函数的方法,给出了当所设计的控制器存在加性摄动时鲁棒非脆弱控制器存在的条件。该控制器能够保证闭环切换系统在任意切换律下渐近稳定。然后应用线性矩阵不等式将鲁棒非脆弱控制器的设计问题转化为一组线性矩阵不等式的可行解问题,从而可借助Matlab中的LMI工具箱直接求解。最后通过仿真算例验证所提方法的有效性。     

不确定抛物线型偏微分方程状态空间模型的保性能控制研究

文章提出关于不确定线性空间分布过程的动态模型。通过配置点谱方法在空间上离散抛物线型偏微分方程空间得到。采用线性矩阵不等式的方法设计保性能控制器;最后,把控制器的设计方法应用到催化反应棒的温度控制问题。     

基于LMI的非线性模糊脉冲奇异摄动系统的鲁棒模糊控制

通过推广一般T-S模糊模型定义了一类非线性模糊脉冲奇异摄动系统,基于线性矩阵不等式(LMI)方法提出一种鲁棒模糊控制新方案,采用并行分布补偿(PDC)的基本思想设计状态反馈控制器,并利用Lyapunov理论证明闭环系统全局指数稳定.最后基于LMI方法,将鲁棒模糊控制器的设计问题转化为线性矩阵不等式问题(LMIP).仿真结果表明了该方法的有效性.     

不确定随机变时滞神经网络的全局渐进稳定性

采用It(o)'s微分公式和不等式分析技巧,研究了一类不确定随机变时滞神经网络的全局渐进稳定性问题.该模型同时考虑了神经网络模型的两种扰动因素,即随机扰动与不确定性扰动.不确定性参数是时变且范数有界的.通过构造适当的Lyapunov泛函,以线性矩阵不等式形式给出了平衡点在均方根意义下的全局渐进稳定性判据,能够利用LMI工具箱很容易地进行检验.此外,仿真示例证明了结论的有效性.     

具有参数摄动的时滞Hopfield神经网络的鲁棒稳定性

 研究一类具有参数摄动的时滞Hopfield神经网络模型的鲁棒稳定性.应用Lyapunov泛函法,给出了平衡点渐近稳定的充分条件.利用矩阵范数的性质及线性矩阵不等式(LMI)理论,又得到了两个便于计算和验证的推论.提供了一种估计网络渐近稳定平衡点吸引域的方法,并详尽地分析了吸引域对神经网络实现联想记忆的影响.数值例子进一步证明了结论的有效性.     

Model reference adaptive control of a soft bending actuator with input constraints and parametric uncertainties

In this article, model reference adaptive control of a pneumatically actuated soft robot has been studied in detail. To deal with the effects of system uncertainties, in the proposed control scheme, parametric uncertainties and input constraints are taken into account. To design such a controller, based on experimental analysis, the robot has been modeled as a second-order Linear Parameter Varying (LPV) system. Then, the dominant dynamics are presented as a Linear Time-Invariant (LTI) system, while uni-directional input constraint has been considered as a critical issue in the control scheme design. Furthermore, to compensate parametric uncertainties as well as unmodeled dynamics, adaptive laws are modified. Finally, the effectiveness is studied in different scenarios on an experimental platform to validate our claims. Moreover, to show the proposed approach capabilities and performance, the proposed controller has been compared with a PID and a recent sophisticated robust-adaptive controller, which presented a new formulation to achieve a better tracking performance with guaranteed stability in the presence of different constraints and unmodeled dynamics.     

High precision position control of electro-hydrostatic actuators in the presence of parametric uncertainties and uncertain nonlinearities

Characterized by high power-to-weight ratio, modularity and energy efficiency, electro-hydrostatic actuators (EHAs) have been successfully applied to aircrafts and submarines, where high precision and repeatability are in high demand. The position tracking performance, however, can be inevitably affected by parametric uncertainties and uncertain nonlinearities. Model inaccuracy or system variations normally require a large loop gain to achieve robust performance, which leads to over-design. Leakage in the fluid power system decreases steady-state accuracy, and friction in the actuator degrades the transient performance or even causes stick-slip motion at low speeds. Furthermore, the system may exhibit limit cycle (or hunting) due to Stribeck friction and integral action. This paper proposes a robust high precision position control strategy incorporating leakage and friction compensation for EHAs. Quantitative feedback theory (QFT) is applied to design a robust controller that satisfies the prescribed performance specifications without over-design, considering model inaccuracy and system variations. The internal leakage is subsequently compensated based on experimental data instead of incorporating an integrator in the controller; hence, limit cycle is avoided, and response speed is improved. Friction in the actuator is identified based on the LuGre friction model and compensated through an observer in the loop. Friction variation and load fluctuation are considered to be output disturbances to be suppressed by the QFT controller. The QFT controller with leakage and friction compensation scheme is verified through experiments on a typical EHA. Both the steady-state and transient position tracking performances are greatly improved.     

T-S模糊系统非脆弱跟踪控制器设计

针对T-S模糊系统,研究了非脆弱H∞跟踪控制器的设计问题.目的是通过设计跟踪控制器使得被控闭环系统满足给定的H∞跟踪控制性能指标.本文采用线性矩阵不等式(LMI)方法,求解过程不必通过二次迭代的两步算法,所设计的控制器在一定的加性参数变化情况下,仍能保证系统的渐进稳定性.最后,通过单关节刚性机械臂系统的仿真实验表明了该方法的有效性.     

Passivity-based non-fragile control of a class of uncertain fractional-order nonlinear systems

This article investigates the issues of passivity and feedback passification of a class of fractional-order (FO) nonlinear systems with time-varying norm-bounded parameter uncertainties in both the state and output matrices. Firstly, new passivity conditions presented by linear matrix inequalities (LMIs) are established based on new notions of passivity of FO systems. Secondly, considering inaccuracies or uncertainties may occur during controller implementation, non-fragile state feedback passification controller is proposed when the states are available. The obtained results extend and improve some recent results. Finally, the applicability and effectiveness of the developed results are examined via numerical examples with simulation results.     

基于多智能体的微电网电压稳定性协调控制系统

针对传统智能优化算法在调节含分布式电源的微电网电压稳定性时不稳定、过早收敛的问题,提出一种基于多智能体的微电网电压稳定性协调控制系统。该系统采用集中式和分布式管理相结合的方式来提高微电网的电压稳定性,在监控电压稳定性指标的同时解决电压越限的问题;同时,使用配电网智能体实时监控分布式电源总控智能体和调压智能体,通过调节分布式电源智能体的有功与无功出力来调节微电网电压。在含有3个分布式电源的IEEE 33节点系统上的仿真测试结果表明,该系统能有效解决含分布式电源的微电网电压越限的问题,调节电压稳定性。     

Robust stability of complex polynomials with annular uncertainties

In this paper, we find necessary and sufficient conditions for the stability of a family of annular, complex polynomials with the possibility of including a center polynomial. The proposed results can be modified to solve the disk problem by simply equating the inner radius of the annuli to zero. These results have applications in the communications arena and some signal processing problems.     

电梯控制系统的速度控制策略研究

通过建立电梯运行速度曲线的数学模型,文章研究了根据设定时间参数与楼层间距自动生成的速度曲线,发现一种提高电梯运行时人在电梯厢的舒适感与运行效率的改进方法,结果表明除了控制电梯控制系统的运行速度外,为提高电梯启动时的舒适感还需要在负载补偿中应用一种基于速度的控制技术。     

Gain stability of the superregenerative parametric amplifier

Gain instabilities due to changes in the parametric elastance amplitude are calculated for superregenerative and negative-resistance parametric amplifiers. On the basis of the comparison, higher stability of the superregenerative amplifier is demonstrated.     

直接转矩控制系统的研究

首先简要介绍直接转矩控制的发展背景,基本原理及其应用范围;其次介绍直接控制的基本特点,它不像矢量控制那样需要复杂的坐标变换;接着简要介绍异步电动机的基本数学模型,得出电机转矩的基本计算公式;之后介绍电机的磁链模型,包括u-i模型及u-i-n模型,并对两种模型的优缺点进行对比分析;最后建立直接转矩控制的仿真模型,并简要分析仿真结果.