一类带有随机、有界时滞网络控制系统的脉冲控制

如何在信道约束下设计控制器对于网络控制系统的研究具有重要意义,为此提出将脉冲控制思想应用于网络控制系统,通过减少反馈过程的通信次数来降低控制策略对信道传输能力的依赖.首先构建网络脉冲控制系统模型;继而利用Lyapunov函数方法得到一类带有随机、有界时滞的网络控制系统的指数稳定性条件,并给出了脉冲控制器参数与系统收敛速度之间的定量关系;最后通过数值仿真结果验证了所提出方法的有效性.     

Networked iterative learning control approach for nonlinear systems with random communication delay

This paper constructs a proportional-type networked iterative learning control (NILC) scheme for a class of discrete-time nonlinear systems with the stochastic data communication delay within one operation duration and being subject to Bernoulli-type distribution. In the scheme, the communication delayed data is replaced by successfully captured one at the concurrent sampling moment of the latest iteration. The tracking performance of the addressed NILC algorithm is analysed by statistic technique in virtue of mathematical expectation. The analysis shows that, under certain conditions, the expectation of the tracking error measured in the form of 1-norm is asymptotically convergent to zero. Numerical experiments are carried out to illustrate the validity and effectiveness.     

测控系统虚拟仪器网络设计

本文就网络化测控系统的虚拟仪器平台模型的搭建及网络通信技术进行介绍,利用DataSocket控件实现的C/S 模式和B/S模式下实现网络通信;并就其实现过程和各模块作了详细阐述.     

测控系统虚拟仪器网络设计

本文就网络化测控系统的虚拟仪器平台模型的搭建及网络通信技术进行介绍,利用DataSocket控件实现的C/S模式和B/S模式下实现网络通信;并就其实现过程和各模块作了详细阐述。     

具有控制时滞和测量数据丢失的直线电机迭代学习控制

针对测量信号存在丢失和控制信号存在时滞的直线电机控制系统,研究PD型迭代学习控制算法的收敛性问题.假设数据丢失描述为概率未知的随机Bernoulli过程,其中丢失概率属于某个已知数值区间,利用超前法解决控制信号存在的时滞问题.基于Bellman-gronwall不等式和$lambda$范数理论,证明了所提出的迭代学习控制策略能够使系统在有限时间内跟踪期望轨迹.最后通过仿真验证了所提出学习算法的有效性.     

面向网络诱导时延和数据包丢失补偿的网络化广义预测控制

针对网络化控制系统中存在的网络诱导时延和数据包丢失, 考虑了网络化广义预测控制问题. 基于多个数据打包传送的通讯方式以及网络诱导时延和数据包丢失预先可知的假设, 提出了一种采用最小预测步长和预测控制增量向量分别补偿网络诱导时延和数据包丢失对系统性能影响的新方法, 给出了相应的网络化模型预测算法和网络化滚动优化算法, 对于被控对象参数未知或缓慢变化的情况, 给出了基于递推最小二乘辨识改进算法的网络化反馈修正算法, 通过仿真验证了所提出网络化算法的有效性.     

Hybrid one-way delay estimation for networked control system

One-way delay estimation in the forward and feedback channels is crucial for a networked control system (NCS) due to its important role in the reliability and availability design. Problems existing in current one-way delay estimation schemes are investigated in this paper. A novel hybrid one-way delay estimation scheme, utilizing the hybrid technique that contains an online monitoring mechanism and an end-to-end estimation method, is proposed to overcome the effects of network asymmetry and delay dynamics in the NCS. Therefore, accurate one-way delay values in the forward and feedback channels can be obtained. In the proposed scheme, only the delay value of the initial packet starting the control loop of the NCS is estimated by the online monitoring mechanism, all the other estimations are performed by the host using the end-to-end method. The experimental results demonstrate that the performance of the proposed novel hybrid one-way delay estimation scheme is better than the other current estimation schemes for the NCS in terms of its high accuracy in tracking delay values as well as requiring lower computation complexity of the system.     

H-infinity measurement-feedback control for discrete-time systems with a single measurement delay

H-infinity control problem for linear discrete-time systems with instantaneous and delayed measurements is studied. A necessary and sufficient condition for the existence of the H-infinity controller is derived by applying reorganized innovation analysis approach in Krein space. The measurement-feedback controller is designed by performing two Riccati equations. The presented approach does not require the state augmentation.     

Networked iterative learning control design for discrete-time systems with stochastic communication delay in input and output channels

This paper develops two kinds of derivative-type networked iterative learning control (NILC) schemes for repetitive discrete-time systems with stochastic communication delay occurred in input and output channels and modelled as 0-1 Bernoulli-type stochastic variable. In the two schemes, the delayed signal of the current control input is replaced by the synchronous input utilised at the previous iteration, whilst for the delayed signal of the system output the one scheme substitutes it by the synchronous predetermined desired trajectory and the other takes it by the synchronous output at the previous operation, respectively. In virtue of the mathematical expectation, the tracking performance is analysed which exhibits that for both the linear time-invariant and nonlinear affine systems the two kinds of NILCs are convergent under the assumptions that the probabilities of communication delays are adequately constrained and the product of the input–output coupling matrices is full-column rank. Last, two illustrative examples are presented to demonstrate the effectiveness and validity of the proposed NILC schemes.     

测量时延在线估计与批间控制器协同设计

批间控制是半导体批次生产过程中常用算法,其关键问题在于能够及时获取上一批次的制程输出,受测量手段及其成本限制,实际的生产制程很难满足这一要求.为此,本文提出一种基于贝叶斯统计分析的测量时延估计算法.在分析晶圆质量与实测时延、估计时延、以及制程漂移之间的逻辑关系的基础上,并将晶圆的质量信息按加工时间顺序划分两个相邻的滚动时间窗口.基于贝叶斯后验概率函数,及时捕获后一个滚动时间窗口内过程输出发生漂移的概率,从而判断是否有测量时延发生,并估算该时延大小.在此基础上,给出批间控制器的测量时延补偿策略,及时调整制程的控制量,提高晶圆的加工品质.仿真结果验证所提出算法的有效性.     

网络控制系统的时延估算及补偿

在网络控制系统中,由于带宽等原因,各个节点在交换数据和通信时会出现时延,导致系统性能下降甚至不稳定。通过时延预估的方法,运用时间戳法估算出时延,将时间戳法和Smith预估补偿控制相结合。通过仿真可观察到比较稳定的输出响应。     

Reduced-order observer-based robust synchronisation control of cold rolling mills with measurement delay

To improve the quality of strip thickness, synchronisation control is investigated for cold rolling mills driven by dual-cylinder electro-hydraulic servo systems. Realising synchronised control in hydraulic automatic gauge control (HAGC) systems of cold rolling mills has challenges with not only the inherent nonlinearities of hydraulic servo systems and uncertainties of load variation but also measurement delay of strip thickness. Since all states are not measurable in practice, output feedback robust synchronisation control problem should be addressed for uncertain nonlinear systems with output delay. Thus, a reduced-order observer-based robust synchronous controller is presented by employing Lyapunov functional stability theory. The controller designed by incorporating the integral of the position synchronisation error of two pistons into state variables successfully guarantees asymptotic convergence to zero of both tracking errors and synchronisation error simultaneously regardless of the nonlinearities and uncertainties as well as the measurement delay. Simulation results in a model obtained from a real cold strip rolling mill demonstrate the effectiveness of the approach.     

网络化最优预测状态估计

当网络诱导时延和数据包丢失确定可知时,提出了一种网络化最优预测状态估计器设计方法,能够补偿网络诱导时延和数据包丢失对估计性能的影响,理论分析表明了随着网络诱导时延或数据包丢失的增加,该估计器在获得明显补偿效果的同时预测估计偏差略微递增,并给出了估计系统的稳定性条件,最后通过仿真和实验验证了所提出方法的有效性和理论分析的正确性.     

有界随机测量时滞的网络控制系统的最优估计

在假设测量没有丢包的情况下, 研究了带有随机测量时滞的网络控制系统的最优估计问题. 利用已知的时 滞分布概率, 建立新的模型来描述随机时滞测量. 进一步将带有时滞的测量等价成每个通道是单时滞的多通道测 量, 从而利用新息重组方法, 通过求解黎卡提方程求解最优估计器. 最后给出仿真实例验证了该算法的有效性.     

网络化控制系统时延测量、分析与预测

针对网络化控制系统（NCS）中的随机时变时延,采用自行开发的基于应用层的测试软件,按照IETF（The Internet Engineering Task Force）的RFC2544规范,进行了6个多月实际测量,获得了170余万个网络时延数据;通过对实验数据进行相关分析,建立了网络时延的自适应自回归（AR）模型;并用自适应最小均方差（LMS）算法对实测的网络时延进行了估计和预测,实验结果表明了算法的有效性。     

Benefits of acceleration measurement in velocity estimation and motion control

The purpose of this work is to investigate the performance of the kinematic Kalman filter (KKF), an accelerometer-assisted velocity estimation method. The most attractive feature of KKF is that it is immune to modeling uncertainties and parameter variations. Conventional velocity estimation methods are analyzed and compared to KKF. It is shown that KKF can perform very well even with low-resolution encoders. A reliable and cost-effective method of measuring angular acceleration is suggested using MEMS accelerometers. Experimental results with low-resolution encoders confirm the superiority of KKF.     

Enhanced measurement and estimation methodology for flexible link arm control

The two objectives of this article are (1) to study the effects of truncation of the infinite series in the assumed mode shapes approach for flexible-link robot arms, and (2) to design an improved Kalman filter for estimation of the rigid and flexible modes for controls purposes. A singular perturbation approach is used to derive an improved reduced-order model that does not correspond simply to truncating the finite series, but includes some additional information about the neglected residual modes. Then, a second time-scale separation is used to design a slow/fast Kalman filter with improved performance for flexible-link arms. © 1994 John Wiley & Sons, Inc.     

Robust fast adaptive fault estimation and tolerant control for T-S fuzzy systems with interval time-varying delay

This paper studies the problem of fault estimation (FE) and the active fault tolerant control (FTC) for Takagi–Sugeno (T-S) fuzzy systems with interval time-varying delay and norm-bounded external disturbance. Based on the fast adaptive fault estimation (FAFE) algorithm, our attention focuses on designing an adaptive observer-based controller to guarantee the filtering error system to be asymptotically stable and satisfy theH_∞ performance index. By constructing a new Lyapunov–Krasovskii functional including the information of the lower and upper delay bounds, the sufficient delay-dependent conditions have been established to guarantee the existence of adaptive observer-based controller in terms of linear matrix inequalities (LMIs). Compared with the constant delay and time-varying delay, the interval time-varying delay is the less conservative form. Furthermore, we make full use of the information of the delay and no terms are ignored when the stability of the system is analysed. In addition, the results for the systems with time-varying structured uncertainties are established. The results of the active FTC are showed in terms of LMIs. Finally, two examples are given to verify the effectiveness of the proposed method.     

基于Internet控制系统延迟的一种解决方法

介绍了基于Internet的网络控制系统的组成及最近的研究状态，对于系统中网络时延这个重要问题进行了分析，通过分析提出了一种针对延迟的动态重发机制的解决方法，在被控端进行延迟时刻规律的完整学习，并且把此规律传给控制端。控制端依照此规律，在延迟发生概率较大的时刻进行瞬时重发，并不断得进行周期性得学习。从而降低了网络延迟情况．