随机切换拓扑下具有区间时变时滞的二阶离散多智能体系统的均方包含控制

研究随机切换拓扑下具有区间时变时滞的二阶离散多智能体系统的均方包含控制问题.通过一个变量变换,把原系统的均方包含控制问题转化为新系统的均方稳定性问题.根据随机稳定性理论和线性矩阵不等式的方法,给出了多智能体系统解决均方包含控制的充分条件.最后,仿真实例验证了理论结果的有效性.     

多体气动弹性系统超声速颤振分析

对一类多体气动弹性系统超声速颤振问题进行研究.分别采用多体动力学理论、活塞理论建立了弹性结构系统的动力学模型与超声速非定常气动力模型,得到了由微分代数方程表示的多体系统气动弹性动力学方程.通过数值求解微分代数方程的特征值问题,研究了多体系统在平衡位置小扰动运动的稳定性,完成了多体气动弹性系统超声速颤振分析.应用该方法研究了板状翼面及含操纵面翼面的超声速颤振问题,并得到了操纵面处于不同位置时翼面的颤振速度.结果表明,所发展的多体气动弹性系统超声速颤振分析方法,适用于由多个部件组成的工程结构颤振分析.     

具有领导者的非线性分数阶多智能体系统的一致性分析

研究了利用非线性分数阶模型描述的具有领导者的多智能体系统的一致性问题.基于智能体之间的通讯拓扑图,设计了系统的控制协议和相应的控制增益矩阵.利用广义Gronwall不等式和分数阶微分方程的稳定性理论,得到了多智能体系统达到一致的充分条件.最后,数值仿真结果显示了理论结果的有效性.     

关于柔性结构动力系统的稳定性与控制

本文考虑了一类具弹性结构的复杂动力学系统的稳定性与控制问题.由于系统的动力学模型为一些常微分与偏微分相互耦合的方程组所描述,且考虑了弹性振动时结构阻尼对运动的影响,从而用传统的方法分析系统的动力学特性时遇到了困难.本文在函数空间中利用泛函分析谱理论与算子半群理论, 论证了系统的解存在、唯一,且适当选取一定的控制之后,能使得系统的弹性振动(包括弯曲振动和扭转振动)指数渐近稳定,亦可保证梁的姿态定位.     

具有Boltzmann阻尼的Petrovsky系统的稳定性

研究具有Boltzmann阻尼的Petrovsky系统的稳定性.首先在合适的假设下,应用线性算子半群理论证明了系统的适定性,进而运用Hilbert空间线性算子半群指数稳定的频域结果证明了具有Boltzmann阻尼Petrovsky系统的指数稳定性.     

具次线性中立项的非线性非自治阻尼动态系统的动力学性质

本文研究时间尺度T上一类同时具有一个次线性中立项和阻尼项的非线性非自治二阶动态系统的动力学行为,利用黎卡提变换技术和不等式技巧,并结合时间尺度上的有关理论,在正则条件下获得该系统多个新的动力学性质,所举例子说明,这些结果推广且改进了近年来已有的部分经典研究成果.     

具有有界输入领航者的二阶非线性多智能体系统的协调跟踪

针对领航者的控制输入为非零但有界的情形,研究了具有本质非线性动态的二阶多智能体系统的协调跟踪问题.利用邻居智能体之间的相对状态信息,分别提出了具有静态和自适应控制增益的两种控制协议.针对静态控制协议情形,基于李雅普诺夫稳定性理论得到了多智能体系统的状态全局指数达到一致时控制增益所需满足的条件.此外,在自适应控制协议作用下,证明了多智能体系统不需要借助任何全局信息就可以实现协调跟踪.最后,仿真实例验证了所得理论结果的正确性.     

非完整性多体编队运动的一种无源化控制方法

讨论了非完整性多体编队运动问题．首先利用动态反馈将单个体的动力学模型线性化为2个三阶输入输出积分链的形式;然后提出一种带有单个体间阻尼注入的非连续分布式控制律,并利用Liapunov方法证明了在该控制律作用下闭环系统的渐进稳定性;最后通过一个平面机器人的编队运动仿真验证了所提方法的有效性．     

基于事件触发策略的多智能体系统的最优主-从一致性分析

研究了具有领导者的线性多智能体系统的主 从一致性问题.借助各智能体间的通讯拓扑所构成的无向图,提出一种基于事件触发的自适应动态规划方法,并使用神经网络的逼近性质设计出了近似最优控制.利用Lyapunov稳定性定理,分析了多智能体误差系统的稳定性,并找到一个该误差系统最终有界的充分条件.数值仿真结果进一步验证了理论分析的有效性.     

机械多体系统碰撞动力学的对称性和守恒量研究

为给复杂机械多体系统碰撞动力学问题的定量和定性分析提供一个强有力新工具,该文将现代分析力学中的对称性理论引入到机械多体外碰撞动力学研究中.首先,基于冲量动量法推导系统碰撞动力学的Euler-Lagrange方程;其次,引进群分析理论,根据不变性原则给出系统存在Noether对称性与Lie对称性的各自条件方程以及得到相应守恒量的形式,为动力学方程的解析积分理论提供了有效途径.最后以一平面开环两连杆机构的碰撞力学为例进行实际分析运用.研究表明,借助对称性和守恒量可以得到机械多体系统动力学更深层次的力学规律和运动特性,可为系统更精确的动态优化设计和先进控制奠定理论基础.     

Passivity-based control and stability analysis for hydro-turbine governing systems

Low-frequency oscillations can occur in hydropower systems under in the new context of power system and the classical controller for hydro-turbine governing systems need to be enhanced with the purpose of improving its stability. We propose a controller based on passivity theory with the aim of damping oscillations in a power system. Passivity-based control arises as a natural choice for hydro-turbine governing system since its open-loop dynamic has a port-Hamiltonian structure, which allows designing a controller that preserves the passive structure in closed-loop via interconnection and damping reassignment. The proposed controller considers the complete non-linear model of the system and guarantees global asymptotic stability in the sense of Lyapunov. Time-domain simulations demonstrate the robustness and proper performance of the proposed methodology under different operative conditions when is compared with the classical controllers.     

Exponential stability of a kind of wave equation with boundary feedback control

The problem of exponential stability of a kind of wave equation with damping and boundary output feedback control is investigated. The spectral structure of the system operator is analyzed and it is shown that the c0-semigroup generated by the system operator is exponential stable if only the coefficients viscous damping and boundary feedback control are not zeros simultaneously.     

Exact Controllability and Boundary Stabilization of Torsional Vibrations of an Internally Damped Flexible Space Structure

In this paper, we study the exact controllability and boundary stabilization of the torsional vibrations of a flexible space structure (such as a solar cell array) modeled by a rectangular panel, incorporating the material damping of the structure. The panel is hoisted at one end by a rigid hub and the other end is totally free. For the attachment of this hub on one side of the panel, the hub dynamics leads to a nonstandard boundary condition. To incorporate internal damping of the material, we assume Voigt-type viscoelasticity of the structure. Exact controllability theory is established using the Hilbert uniqueness method by means of a control torque applied only on the rigid hub of the panel. At the same time, uniform exponential energy decay rate is obtained directly for the solution of this problem.     

Exponential stabilization of a flexible structure with a local interior control and under the presence of a boundary infinite memory

In this paper, we deal with the interior stabilization problem of a flexible structure governed by a hyperbolic partial differential equation coupled to two ordinary differential equations. Contrary to the previous works on the system, the boundary control is subject to the presence of an infinite memory term. In order to deal with such a nonlocal term, the minimal state approach is invoked. Specifically, a localized interior control is proposed in order to compensate the infinite memory effect. Thereafter, reasonable assumptions on the memory kernel are evoked so that the closed-loop system is shown to be well-posed thanks to semigroups theory of linear operators. Furthermore, the resolvent method is used to establish the exponential stability of the system.     

A novel of fuzzy PSS based on new objective function in multimachine power system

This article proposed a new control strategy based on Takagi–Sugeno fuzzy model for deceasing the power system oscillation. This controller is based on the parallel distributed compensation structure, the stability of the whole closed‐loop model is provided using a general Lyapunov‐Krasovski functional. Also, in this article, a new objective function has been considered to test the proposed Fuzzy Power System Stabilizer in different load conditions which increase the system damping after the system undergoes a disturbance. So, for testing the effectiveness of the proposed controller, the damping factor, damping ratio, and a combination of the damping factor and damping ratio were analyzed and compared with the proposed objective function. The effectiveness of the proposed strategy has been used over 16 machine 68 bus power system. The eigenvalue analysis and nonlinear time domain simulation results proof the effectiveness of the proposed method. © 2015 Wiley Periodicals, Inc. Complexity 21: 288–298, 2016     

Exponential Decay Rates for Structural Acoustic Model with an Overdamping on the Interface and Boundary Layer Dissipation

We study uniform stability properties of a strongly coupled system of Partial Differential Equations of hyperbolic/parabolic type, which arises from the analysis and control of acoustic models with structural damping on an interface. A challenging feature of the present model is the presence of additional strong boundary damping which is responsible for lack of uniform stability of the free system ( overdamping phenomenon). It has been shown recently that by applying full viscous damping in the interior of the domain and suitable static damping on the interface, then the corresponding feedback system is uniformly stable. In this article we prove that uniform decay rates of solutions to the system can be achieved even if viscous damping is active just in an arbitrary thin layer near the interface.     

Comparative study on control concepts of a robot manipulator with multiple-link/joint flexibilities

If one is dealing with active vibration suppression on a highly nonlinear flexible system, various techniques are needed. On the one hand a suitable dynamic model of the system is required. And on the other hand intelligent model based control concepts are necessary for active vibration damping. We deal with a basic model, where the flexibilities are approximated with linear springs and dampers, a so called lumped element model (LEM). For the control design we propose a control structure with two degrees of freedom (2DoF) for solving the tracking problem, based on the LEM. Such an approach allows designing the feedforward part independently of the feedback part. Hereby the feedforward control is based on the flatness approach, while for the feedback control several strategies are studied using acceleration- and gyrosensor-measurements. The contribution is completed with a validation by measurements from a very fast trajectory on an articulated robot with two flexible links and three elastic joints. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the stabilizability of a structural acoustic model which incorporates shear effects in the structural component

In this paper we consider a linear three-dimensional structural acoustic model which takes account of displacement, rotational inertia and shear effects in the flat flexible structural component of the model. Thus the deflections of the structural component of the structure are governed by the Reissner–Mindlin plate equations. We show strong stabilization of the coupled model without incorporating viscous or boundary damping in the equations for the gas dynamics and without imposing geometric conditions. It turns out that damping is needed in the interior of the plate, to which end Kelvin–Voigt damping is introduced in the plate equations. As our main tool we use a resolvent criterion for strong stability due to Tomilov.     

基于营养动力学的广义捕食者—食饵—生物残体系统的变结构控制

利用变结构控制理论研究了一个基于营养动力学的广义捕食者一食饵一生物残体系统的变结构控制问题.首先,给出了基于营养动力学的广义捕食者一食饵一生物残体系统的正则平衡点的稳定性条件;同时利用广义系统理论研究了基于营养动力学的广义捕食者一食饵一生物残体系统的正则化问题,得到了其可正则化条件;最后,对其实施控制,并利用变结构控制理论,实现了基于营养动力学的广义捕食者一食饵一生物残体系统的稳定化,保持了系统的持续生存.