共查询到19条相似文献，搜索用时 156 毫秒
1.
2.
3.
针对一类不确定非线性时滞系统,提出了一种具有确定逼近域的自适应模糊控制器的设计方案。在动态面控制（DSC）的基础上,通过时滞代换技巧,使得自适应模糊逼近器的输入为参考信号,从而可以明确定义逼近域,同时可以处理系统中完全未知的时滞信号。基于Lyapunov-Krasovskii范函,证明闭环系统所有信号为半全局一致有界的,并且跟踪误差可以收敛到原点附件的一个小邻域内。仿真结果进一步说明了该方法的有效性。 相似文献
4.
本文研究了一类范数有界不确定离散状态时滞系统的鲁棒控制问题.通过采用新的方法,得到了使得系统鲁棒渐近稳定的改进的时滞相关准则,设计了使得系统鲁棒镇定的线性无记忆状态反馈控制器.所得时滞相关准则以严格线性矩阵不等式形式表示,且包含了更少的变量. 相似文献
5.
对一类含有时变时滞的不确定切换系统,研究了保成本控制器的设计问题。基于Lyapunov稳定性理论,给出了保成本控制器存在的充分条件,并借助于线性矩阵不等式方法获得了控制器的参数化形式。进一步,将次优保成本控制器的设计问题转化为线性矩阵不等式约束下的凸优化问题。 相似文献
6.
针对不确定时滞相关广义系统的H∞鲁棒控制问题进行研究,目的是设计线性无记忆状态反馈控制器,使得对闭环系统所有的允许的不确定性正则、无脉冲、稳定且具有满意的H∞性能.将时滞相关广义系统的新有界实引理以严格的不等式线性矩阵方法给出,这些都是通过引入新的Lyapunov-Krasovskii泛函,使用詹森不等式得出的.其次,在新的有界实引理的基础上给出了(不确定)时滞相关广义系统的(鲁棒)控制器存在的充分条件.所得出的结果都以严格的线性矩阵不等式形式表示并且都是时滞相关的,未涉及系统矩阵的分解.最后,通过数值算例说明了该方法具有较小的保守性和有效性. 相似文献
7.
采用稿件网络采编系统对期刊论文发表时滞的影响 ——以《中华神经科杂志》为例 总被引：3，自引：2，他引：1
为了探讨期刊网络采编系统对缩短期刊论文发表时滞的作用,对比分析了《中华神经科杂志》采用中华医学会杂志社自主研发的网络采编系统前后两个年度发表的全部论文的发表时滞及各时滞组文章的比例。结果显示: 采用网络采编系统后,期刊论文发表时滞有所缩短,长时滞文章数的比例下降,中等时滞文章数的比例上升; 网络采编系统对短时滞文章产生的作用不及中等时滞和长时滞的文章。 相似文献
8.
由于网络用户数据呈现稀疏状导致对用户信任值评价控制不准确,难以实现有效推荐。传统方法中使用语义Web结合协同过滤方法进行用户信任网络控制,在协同过滤中由于冷启动和不确定时延导致相似用户发现较为困难。提出一种基于Lyapunov稳定性理论的用户信任度评价渐进控制算法,完成用户信任网络控制器设计,并进行用户推荐模型构建,实现对用户信任度的准确评价。仿真实验表明,使用该算法和模型进行网络交易用户信任评价,能解决评价系统中存在的不确定误差、干扰和时滞等问题,用户推荐模型鲁棒性好。 相似文献
9.
一类具有动态领导者和时滞的多主体系统的一致性 总被引：1，自引：0，他引：1
研究了一类具有动态领导者并且存在时变耦合时滞的多主体系统的一致性问题．在所考虑的模型中,领导者的速度不能被精确量测．为了跟踪这样一个领导者主体,将对每个跟随者主体构造分散式状态估计器以及设计基于邻居的控制器;同时,由于耦合时滞的存在,基于邻居的控制器和状态估计器均包含了时变时滞的作用．当多主体系统的耦合拓扑是固定的或切换的有向图时,跟随者与领导者之间的跟踪误差得到了估计．特别地,可以证明,当动态领导者的速度可以被精确量测时,每一个跟随者都能够跟踪上领导者． 相似文献
10.
11.
A delay distribution based stability analysis and synthesis approach for networked control systems 总被引：1，自引：0，他引：1
Communication delays in networked control systems (NCSs) has been shown to have non-uniform distribution and multifractal nature. This paper proposes a delay distribution based stability analysis and synthesis approach for NCSs with non-uniform distribution characteristics of network communication delays. A stochastic control model related with the characteristics of communication networks is established to describe the NCSs. Then, delay distribution-dependent NCS stability criteria are derived in the form of linear matrix inequalities (LMIs). Also, the maximum allowable upper delay bound and controller feedback gain can be obtained simultaneously from the developed approach by solving a constrained convex optimization problem. Numerical examples showed that the results derived from the proposed method are less conservativeness than those derived from the existing methods. 相似文献
12.
13.
H.R. Marzban 《Journal of The Franklin Institute》2004,341(3):279-293
A method for finding the optimal control of a linear time varying delay system with quadratic performance index is discussed. The properties of the hybrid functions which consists of block-pulse functions plus Legendre polynomials are presented. The operational matrices of integration, delay and product are utilized to reduce the solution of optimal control to the solution of algebraic equations. Illustrative examples are included to demonstrate the validity and applicability of the technique. 相似文献
14.
《Journal of The Franklin Institute》2021,358(14):7073-7095
This paper is devoted to adaptive neural network control issue for a class of nonstrict-feedback uncertain systems with input delay and asymmetric time-varying state constraints. State-related external disturbances are involved into the system, and the upper bounds of disturbances are assumed as functions of state variables instead of constants. Additionally, during the approximations of unknown functions by neural networks, the online computation burdens are declined sharply, since the norms of neural network weight vectors are only estimated. In the process of dealing with input delay, an auxiliary function is applied such that the conditions for time delay are more general than the ones in existing literature. A novel adaptive neural network controller is designed by constructing the asymmetric barrier Lyapunov function, which guarantees that the output of system has a good tracking performance and the state variables never violate the asymmetric time-varying constraints. Finally, numerical simulations are presented to verify the proposed adaptive control scheme. 相似文献
15.
恶意节点在一段时间内发送相当数量的RREQ消息,正常节点则广播入侵节点的RREQ信息,从而造成正常节点能源、存储资源和网络带宽耗尽,网络遭受破坏。研究了AODV路由协议的缺陷,针对路由请求RREQ消息广播的特性,实现了RREQ泛洪攻击。用NS对攻击过程进行仿真实验,用网络性能的两个重要变量（数据分组递交率和网络延迟）来衡量攻击结果。实验证明,RREQ泛洪攻击十分有效。 相似文献
16.
This paper focuses on the problem of chaos control for the permanent magnet synchronous motor with chaotic oscillation, unknown dynamics and time-varying delay by using adaptive sliding mode control based on dynamic surface control. To reveal the mechanism of motor system and facilitate controller design, the dynamic behavior of the system is investigated. Nonlinear items of system model, upper bounds of time delays and their derivatives are taken as unknown in the overall process. A RBF neural network with an adaptive law, which eliminates restrictions on accurate model and parameters, is employed to cope with unknown dynamics. In order to solve issues such as chaotic oscillation, ‘explosion of complexity’ of backstepping, and chattering associated with sliding mode control, a sliding mode controller is developed within the framework of dynamic surface control by the hybrid of adaptive technology and RBF neural network. In addition, an appropriate Lyapunov function is employed to demonstrate the system stability. Finally, the feasibility of the proposed scheme is testified by simulation. 相似文献
17.
18.
Sayyed Mohammad Hoseini 《Journal of The Franklin Institute》2018,355(16):7895-7923
An adaptive numerical method for solving multi-delay optimal control problems with piecewise constant delay functions is introduced. The proposed method is based on composite pseudospectral method using the well-known Legendre–Gauss–Lobatto points. In this approach, the main problem converts to a mathematical optimization problem whose solution is much more easier than the original one. The necessary conditions of optimality associated to nonlinear piecewise constant delay systems are derived. The method is easy to implement and provides very accurate results. 相似文献
19.
Jiali Ma Shengyuan Xu Yongmin Li Yuming Chu Zhengqiang Zhang 《Journal of The Franklin Institute》2018,355(13):5503-5519
This paper focuses on the problem of adaptive output feedback control for a class of uncertain nonlinear systems with input delay and disturbances. Radial basis function neural networks (NNs) are employed to approximate the unknown functions and an NN observer is constructed to estimate the unmeasurable system states. Moreover, an auxiliary system is introduced to compensate for the effect of input delay. With the aid of the backstepping technique and Lyapunov stability theorem, an adaptive NN output feedback controller is designed which can guarantee the boundedness of all the signals in the closed-loop systems. Finally, a simulation example is given to illustrate the effectiveness of the proposed method. 相似文献