具有介质访问约束的网络化控制系统H∞状态估计

研究了一类存在介质访问约束和信号量化的网络化控制系统的H∞状态估计问题。首先,考虑到介质访问约束和信号量化的影响,将信号量化误差转化为扇形有界的不确定性,对由于访问约束而未获得网络传输的系统输出采用加权补偿策略,根据网络介质的随机访问机制将网络化系统建模为具有不确定性的马尔可夫跳跃系统。然后,在此基础上借助李雅普诺夫稳定性理论和H∞性能约束条件,利用线性矩阵不等式(linear matrix inequality,LMI)方法给出状态估计器存在的充分条件,所设计的状态估计器使得估计误差系统渐近稳定且具有给定的H∞性能。最后,通过仿真实例验证了该设计方法的有效性。

Sliding mode H_∞ control for a class of uncertain nonlinear state-delayed systems

A new proportional-integral （PI） sliding surface is designed for a class of uncertain nonlinear state-delayed systems. Based on this, an adaptive sliding mode controller （ASMC） is synthesized, which guarantees the occurrence of sliding mode even when the system is undergoing parameter uncertainties and external disturbance. The resulting sliding mode has the same order as the original system, so that it becomes easy to solve the H∞ control problem by designing a memoryless H∞ state feedback controller. A delay-dependent sufficient condition is proposed in terms of linear matrix inequalities （LMIs）, which guarantees the sliding mode robust asymptotically stable and has a noise attenuation level γ in an H∞ sense. The admissible state feedback controller can be found by solving a sequential minimization problem subject to LMI constraints by applying the cone complementary linearization method. This design scheme combines the strong robustness of the sliding mode control with the H∞ norm performance. A numerical example is given to illustrate the effectiveness of the proposed scheme.

H_∞ Control for 2-D Discrete State Delayed Systems in the Second FM Model

这份报纸涉及 H 控制的问题为二维(2-D ) 分离州的延期系统由第二 Fornasini 和 Marchesini (FM ) 描述了州空间当模特儿。为这个 2-D 系统有 H 噪音变细的一个足够的条件以某个线性矩阵不平等(LMI ) 被给。最佳的 H 控制器被解决一个凸的优化问题获得。最后，一个模拟例子被给说明建议结果的有效性。

A TD-DFT Study for the Excited State Calculations of Microhydration of N-Acetyl-Phenylalaninylamide (NAPA)

Investigating the impact of microhydration on the excited-states and electronic excitation properties of biomolecules has remained one of the important yet challenging aspects of science because of the complexity of developing models. However, with the advent of computational chemistry methods such as TD-DFT, many useful insights about the electronic excitation energy and excited-state nature of biomolecules can be explored. Accordingly, in our study, we have incorporated the TD-DFT/wB97XD/cc-pVTZ method to study the excited state properties of N-acetyl phenylalanine amide (NAPA-A(H2O) n) (n = 1 to 4) clusters from ground to the tenth lowest gaseous singlet excited state. We found that the C=O bond length gradually increases both in N-terminal amide and C-terminal amide after the sequential addition of water molecules because of intermolecular H-bonding and this intermolecular H-bonding becomes weaker after the sequential addition of H2O molecules. The UV absorption maxima of NAPA-A (H2O)n (n = 1 - 4) clusters consisted of two peaks that are S5←S0 (1st absorption) and S6←S0 (2nd absorption) excitations. The first absorption maxima were blue-shifted with the increase in oscillator strength. This means that strong H-bonds reduce the charge transfer and make clusters more rigid. On the other hand, the second absorption maxima were red-shifted with the decrease in oscillator strength. In the ECD spectra, the negative bands indicate the presence of an amide bond and L-configuration of micro hydrated NAPA-A clusters. Finally, our calculated absorption and fluorescence energy confirm that all the NAPA-A (H2O) n (n = 0 - 4) clusters revert to the ground state from the fluorescent state by emitting around 5.490 eV of light.

Augmented Lyapunov approach to H_∞ state estimation of static neural networks with discrete and distributed time-varying delays

This paper deals with H∞ state estimation problem of neural networks with discrete and distributed time-varying delays. A novel delay-dependent concept of H∞ state estimation is proposed to estimate the H∞ performance and global asymptotic stability of the concerned neural networks. By constructing the Lyapunov-Krasovskii functional and using the linear matrix inequality technique, sufficient conditions for delay-dependent H∞ performances are obtained, which can be easily solved by some standard numerical algorithms. Finally, numerical examples are given to illustrate the usefulness and effectiveness of the proposed theoretical results.

Mixed H_2/H_∞ State Feedback Attitude Control of Microsatellite Based on Extended LMI Method

For the appearance of the additive perturbation of controller gain when the controller parameter has minute adjustment at the initial running stage of system,to avoid the adverse effects,this paper investigates the mixed H_2/H_∞ state feedback attitude control problem of microsatellite based on extended LMI method.Firstly,the microsatellite attitude control system is established and transformed into corresponding state space form.Then,without the equivalence restriction of the two Lyapunov variables of H_2 and H∞performance,this paper introduces additional variables to design the mixed H_2/H_∞ control method based on LMI which can also reduce the conservatives.Finally,numerical simulations are analyzed to show that the proposed method can make the satellite stable within 20 s whether there is additive perturbation of the controller gain or not.The comparative analysis of the simulation results between extended LMI method and traditional LMI method also demonstrates the effectiveness and feasibility of the proposed method in this paper.

Three-dimensional nonlinear H_2/H_∞ guidance law based upon approach of solving the state feedback Nash balance point

Based upon the theory of the nonlinear quadric two-person nonzero-sum differential game,the fact that the time-limited mixed H2/H∞ control problem can be turned into the problem of solving the state feedback Nash balance point is mentioned. Upon this,a theorem about the solution of the state feedback control is given,the Lyapunov stabilization of the nonlinear system under this control is proved,too. At the same time,this solution is used to design the nonlinear H2/H∞ guidance law of the relative motion between the missile and the target in three-dimensional(3D) space. By solving two coupled Hamilton-Jacobi partial differential inequalities(HJPDI),a control with more robust stabilities and more robust performances is obtained. With different H∞ performance indexes,the correlative weighting factors of the control are analytically designed. At last,simulations under different robust performance indexes and under different initial conditions and under the cases of intercepting different maneuvering targets are carried out. All results indicate that the designed law is valid.

Robust H_∞ output feedback controller design for linear uncertain discrete-time switched systems via state reset

This paper studies the problem of robust H∞ output feedback controller via state-reset for linear uncertain discrete-time switched systems. Using multiple Lyapunov functions,we address an output feedback controller under arbitrary switching signals,in which an H∞ performance is required. The condition is shown in the form of linear matrix inequalities (LMI). Finally,a numerical example shows the feasibility of the designed controller and illustrates that the new sufficient condition has lower conservation and more optimized H∞ tfperformance.

一类线性切换系统H_∞状态反馈控制:LMI方法

研究一类由任意有限多个线性子系统组成的切换系统的H∞状态反馈控制问题.利用Lyapunov函数方法,给出由线性矩阵不等式(LM I)表示的控制器存在的充分条件,并设计了相应的子控制器和切换策略.最后给出一个数值仿真实例,证明了所得结论的有效性.

不确定时滞系统的时滞依赖鲁棒非脆弱H_∞控制

基于线性矩阵不等式(LMI)方法,研究了不确定时滞线性系统的鲁棒非脆弱H_∞状态反馈控制器的设计问题,以一个LMI形式给出了控制器存在的充分条件,而且该LMI是与时滞相关的。同时,经过全等变换、变量变换和Schur补引理,该LMI的所有参数都是线性的,这样参数无需预取就可以利用LMI Toolbox获得解。实例表明了上述设计方法的有效性。

磁悬浮系统的H_∞状态反馈设计

理论上H∞状态反馈设计只要求解一个Riccati方程,但常会得出一种无意义的结果。提出H∞状态反馈设计还应该加一个鲁棒性约束,即灵敏度函数的峰值。增加了鲁棒约束下的设计是最佳的设计,才能得到最佳的扰动抑制性能。还指出H∞状态反馈设计中的性能指标γ和权系数都是有量纲的,并详细说明了性能指标和权系数的确定方法。以磁悬浮系统为例,对H∞状态反馈设计中的权系数进行了详细的讨论。所提出的设计思想对一般的状态反馈设计也是有益的。

区间变时滞不确定线性系统带记忆H_∞状态反馈控制

一类存在范数有界不确定性的线性时变时滞系统,其时变时滞仅给出时滞变化的上下界,而对时滞变化率未作任何约束.对于这类区间时变时滞系统,给出了一种新型的Lyapunov-Krasovskii泛函讨论其稳定性,通过分割平均时滞的方法减小保守性,得到以线性矩阵不等式(LMI)形式给出的稳定性判据.最后分析并给出了一种带记忆的H_∞状态反馈控制器,数值实例表明了本文方法的有效性.

线性奇异系统的H_∞控制问题:状态反馈情形

讨论了线性奇异系统的状态反馈H∞ 控制问题 ,阐述了其和一个正常状态空间线性系统的状态反馈H∞控制问题的等价性 ;利用线性矩阵不等式 (LMI)的方法 ,给出了一个使闭环系统无脉冲模 ,内稳定 ,且满足H∞

无人机侧向运动H_∞控制器设计及仿真

研究了鲁棒控制中H_∞状态反馈方法在无人机侧向控制律设计中的应用;建立了无人机侧向运动的小扰动方程,根据控制目标选取了合适的广义状态变量,建立了广义被控对象,应用matlab鲁棒控制工具箱中线性矩阵不等式(LMI)的求解方法设计了系统H_∞状态反馈控制器,并进行了数字仿真验证;以无人机侧向运动中滚转控制通道的H_∞鲁棒控制器设计为例,给出设计过程及仿真结果;与PID控制器的控制效果进行比较,说明控制器能够使系统有更好的动态和稳态性能,且比PID控制器对外界噪声干扰有较好的抑制作用,现已成功应用于某型无人机。

Comparative Study of Trajectory Tracking Control for Automated Vehicles via Model Predictive Control and Robust H-infinity State Feedback Control

A comparative study of model predictive control(MPC)schemes and robust Hstate feedback control(RSC)method for trajectory tracking is proposed in this paper.The main objective of this paper is to compare MPC and RSC controllers’performance in tracking predefined trajectory under different scenarios.MPC controller is designed based on the simple longitudinal-yaw-lateral motions of a single-track vehicle with a linear tire,which is an approximation of the more realistic model of a vehicle with double-track motion with a non-linear tire mode.RSC is designed on the basis of the same method as adopted for the MPC controller to achieve a fair comparison.Then,three test cases are built in CarSim-Simulink joint platform.Specifically,the verification test is used to test the tracking accuracy of MPC and RSC controller under well road conditions.Besides,the double lane change test with low road adhesion is designed to find the maximum velocity that both controllers can carry out while guaranteeing stability.Furthermore,an extreme curve test is built where the road adhesion changes suddenly,in order to test the performance of both controllers under extreme conditions.Finally,the advantages and disadvantages of MPC and RSC under different scenarios are also discussed.

连续时变不确定系统约束方差/H_∞鲁棒状态滤波

基于上限方差配置的混合方差／H∞设计方法可得到满意的设计结果.本文用一个修正的Riccati方程研究了一类时变不确定系统的混合方差／H∞状态滤波器，导出了滤波器的一般公式．对所允许的扰动由该公式所确定的滤波器可使稳态滤波误差方差上限及误差系统的H∞指标均小于指定值，因而具有较好的鲁棒性．

不确定系统D稳定的鲁棒H_∞可靠性控制

研究了一类不确定系统区域稳定的鲁棒H∞可靠性控制器的设计方法,其目的是通过设计状态反馈控制器,使闭环系统的极点被配置在给定的圆盘中,同时,当有外生扰动,以及所有可能的不确定及其敏感执行器失灵的时候,依然能满足闭环传递函数的H∞范数有界的约束。借助于广义的Riccati矩阵不等式,给出了控制器存在的充分条件,同时给出了所期望控制器的解析式。最后,通过一个仿真例子,说明该方法的可行性。

基于LMI的Delta域内的H_∞状态反馈设计

利用 L MI方法讨论和研究 Delta算子描述下的线性定常系统的 H∞ 控制问题 ,并给出了连续系统、Z变换所得到的离散系统和 Delta算子所描述的系统三者的 H∞ 控制问题的比较。结果表明 ,Delta算子所描述的系统的设计方法更适合于离散系统 。

基于扩展LMI的多目标H_2/H_∞状态反馈控制综合

对于连续时间系统的多目标H2／H∞控制问题通过状态反馈给出了一个新的综合方法。该方法依赖于引入的附加变量,降低了通常条件下基于LMI的多目标控制问题的保守性。新方法应用消去引理(Elimination Lemma)得出扩展的H2性能和H∞性能的LMI约束条件,使得与控制器参数相关的优化变量和系统矩阵之间是独立的,能够使用不同的Lyapunov矩阵变量来处理多目标控制问题,仿真结果验证了新方法的有效性。

基于状态观测器的H_∞状态反馈控制

本文提出一种基于状态观测器的H_∞曲状态反馈控制,把输出反馈的H_∞控制问题转换成使用状态观测器的H_∞控制问题.通过直接求解状态空间方程,可以获得使用状态观测器的H_∞控制器及其存在的充要条件,它依赖于两个Rjccati方程的解,而且对控制对象的约束不需要满足所谓的正交条件,状态观测器的阶数与控制对象相同,它的输出是控制对象在最坏扰动作用下的状态估计值。