Hilbert空间中关于Lipschitzian单调算子的变分不等式逼近解

用改进的算法证明了Hilbert空间中关于Lipschitzian单调算子的变分不等式一个强收敛定理,并推导了一个Hilbert空间中关于Lipschitzian伪压缩算子的已有结果.从而改进了近期相关结果.     

新的带有不确定性中立系统的稳定性条件

主要研究了一类新的带有不确定性中立系统的稳定性条件。通过选取适当的Lyapunov泛函,使用牛顿莱布尼茨公式和积分不等式的适当放大,得到了新的判别不确定性中立系统渐近稳定的条件。最后通过数值算例来验证了此方法的可行性以及更低的保守性。     

时滞相关的非线性广义系统的保性能控制

针对一类具有时滞相关和具有非线性扰动的不确定广义系统,研究了该系统的保性能控制问题。目的是设计一个有记忆的状态反馈控制器,不仅使得闭环系统渐进稳定而且相应的性能指标不超过某个确定的上界。基于Lyapunov函数方法和线性矩阵不等式(LMI),得到闭环系统渐进稳定的充分条件和保性能控制器的设计方法。最后通过数值算例说明了所给方法的有效性。     

一类不确定模糊系统的指数稳定性问题研究

基于T-S模糊模型和线性矩阵不等式(LMI)技术,研究一类带有状态不确定项的模糊系统的指数稳定性和被估计的系统收敛率,并基于模糊模型和模糊控制器,设计一种模糊状态观测器,应用线性矩阵不等式技术(LMI)得出控制器增益和观测器增益,并通过实例验证结果的有效性.     

Robust H∞ control for neutral stochastic uncertain systems with time-varying delay

The problem of robust H∞ control for uncertain neutral stochastic systems with time-varying delay is discussed. The parameter uncertaintie is assumed to be time varying norm-bounded. First, the stochastic robust stabilization of the stochastic system without disturbance input is investigated by nonlinear matrix inequality method. Then, a full-order stochastic dynamic output feedback controller is designed by solving a bilinear matrix inequality (BMI), which ensures a prescribed stochastic robust H∞ performance level for the resulting closed loop system with nonzero disturbance input and for all admissible uncertainties. An illustrative example is provided to show the feasibility of the controller and the potential of the proposed technique.     

Non-fragile guaranteed cost control of discrete-time fuzzy bilinear system

This paper focuses on the problem of non-fragile guaranteed cost control for a class of T-S discrete-time fuzzy bilinear systems (DFBS). Based on the parallel distributed compensation (PDC) approach, the sufficient conditions are derived such that the closed-loop system is asymptotically stable and the cost function value is no more than a certain upper bound in the presence of the additive controller gain perturbations. The non-fragile guaranteed cost controller can be obtained by solving a set of bilinear matrix inequalities (BMIs). The Van de Vusse model is utilized to demonstrate the validity and effectiveness of the proposed approach.     

二次D稳定约束下不确定T-S模糊系统的L∞鲁棒可靠控制

针对一类受持续有界扰动的T-S不确定模糊系统,提出了考虑执行器故障的鲁棒可靠控制器设计方法。引入基于L_∞范数理论的鲁棒性能指标及二次D稳定的概念,给出了鲁棒可靠控制器存在的充分条件。通过求解线性矩阵不等式完成可靠控制器的设计,从而使系统即使在发生执行器故障的情况下仍能满足给定的L_∞性能指标,并且闭环系统二次D稳定。仿真实例表明了本方法的有效性。     

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.     

不同粗糙度平面上静止颗粒堆底的切应力分布

在两种不同粗糙底面上测量了用从固定点以相同流量落下颗粒的方法制备而成的圆锥堆底的切向应力分布. 结果显示, 粗糙度大的底面有相对较大的切向应力. 利用一般的力平衡方程、库仑不等式、圆锥堆侧面的自由边界条件以及测量的数据可以验证, 堆底面切向应力强度与法向应力分布出现中心凹陷现象有关, 切向应力越大凹陷现象越明显. 另外, 提出了一个颗粒堆的非线性应力关系唯象模型.