Performance Compensation of Networked Control Systems with Network Delay

2011 ◽  
Vol 268-270 ◽  
pp. 793-797
Author(s):  
Jie Wang ◽  
Song Gao ◽  
Yong Yang

The networked control system typically introduces network delay that have not been considered at the design stage. As a consequence, the system performance is degraded with respect to the expected response. This thesis introduces a methodology to apply external gain assist networked control systems. The proposed methodology uses externalgain to modify the controller output with respect to the current network traffic conditions in order to enable an existing controller for networked control systems and compensate the performance degradetion induced by network delay. This methodology can change existing traditional controller directly to network controller and not modify the original control algorithms.

2001 ◽  
Author(s):  
Octavian Beldiman ◽  
Linda G. Bushnell ◽  
Gregory C. Walsh ◽  
Hua O. Wang ◽  
Yiguang Hong

Abstract In this paper we study the effect of external perturbations on a networked control system. We start by assuming that the non-networked system without perturbation is exponentially stable. Then, for fast enough networks we show that if the perturbation is bounded the networked system is ultimately bounded and if the perturbation is vanishing then the networked system is asymptotically stable. We conclude the paper with simulations verifying the results.


2013 ◽  
Vol 718-720 ◽  
pp. 1836-1841
Author(s):  
Xue Feng Zhang ◽  
Yan Xia Shen ◽  
Hua Ping Zhang

The problem of output feedback stabilization for networked control system with time-varying delay is discussed. By constructing a novel LyapunovKrasovskii functional,the output feedback controller is obtained in terms of LMIs. The dynamics information of the time-varying delay is taken into account in the structured controller, and the obtained result is less conservative. A numerical example is given to illustrate the effectiveness of the presented method.


2010 ◽  
Vol 44-47 ◽  
pp. 1867-1671
Author(s):  
Zhi Hong Huo ◽  
Yuan Zheng ◽  
Chang Xu

Networked control systems with network-induced delay, packet loss and parameters uncertainty is modeled in this paper, consider the sensors that can’t send information to controller and the actuators that can’t receive information calculated and sent by the controller, the integrity design of the networked control system with sensors failures and actuators failures is analyzed based on robust fault-tolerant control theory. Parametric expression of controller is given based on feasible solution of linear matrix inequality. After detailed theoretical analysis, the simulation results is provided, which further demonstrated the proposed scheme.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Zhongda Lu ◽  
Lijing Wang ◽  
Fengbin Zhang ◽  
Fengxia Xu

This paper considers the stability andH∞control problem of networked control systems with time delay. Taking into account the influence of network with delay, unknown input disturbance, and uncertainties of the system modeling, meanwhile we establish a precise, closed-loop model for networked control systems with time delay. By selecting a proper Lyapunov-Krasovskii function and using Lyapunov theorem, a sufficient condition for stability of the system in the form of LMI is demonstrated, corresponding controller parameters are acquired, and the convergence of the control algorithm is proved. The simulation example shows that the construction of the network robust control system with time delay indeed improves the stability performance of the system, which indicates the effectiveness of the design.


2014 ◽  
Vol 989-994 ◽  
pp. 3359-3362
Author(s):  
Guan Qun Liu

One of the research works of network control systems is the effect of network upon control systems. A simulation platform of networked control systems is designed for this purpose. Matlab is used to build models of real systems. Communication between controller and process is fulfilled with Winsock. The simulation platform supports many control algorithms and gives good environment for the analysis and gives good environment for the analysis and design of networked control systems.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Ashraf F. Khalil ◽  
Jihong Wang

Networked control system is a research area where the theory is behind practice. Closing the feedback loop through shared network induces time delay and some of the data could be lost. So the network induced time delay and data loss are inevitable in networked control Systems. The time delay may degrade the performance of control systems or even worse lead to system instability. Once the structure of a networked control system is confirmed, it is essential to identify the maximum time delay allowed for maintaining the system stability which, in turn, is also associated with the process of controller design. Some studies reported methods for estimating the maximum time delay allowed for maintaining system stability; however, most of the reported methods are normally overcomplicated for practical applications. A method based on the finite difference approximation is proposed in this paper for estimating the maximum time delay tolerance, which has a simple structure and is easy to apply.


Networked Control System (NCS) is a method composed of physically shared smart devices that can observe the surroundings, work on it, and converse with one another by means of a communication system to attain a widespread purpose. Characteristic examples that fall into this section are Wireless Sensors and Actuators Networks (WSANs) for ecological analyzing and checking, multi-vehicle systems for composed investigation, camera systems for observation, multicamera facilitated movement catch, shrewd lattices for vitality circulation and the executives, and so forth. NCSs changes from increasingly customary control systems as a result of their interdisciplinary which needs the combination of control hypothesis, correspondences, software engineering and programming designing. Plenty of communication modes are available from telephone lines, cell phone networks, satellite networks and most widely used is internet. The choice of network depends upon the application to be served. Internet is the most suitable and inexpensive choice for many applications where the plant and the controller are far from each other. The troubles present in the structure of control systems that are solid to correspondence parameters like transfer speed, arbitrary deferral and packet loss, to computational parameters in light of the tremendous amount of information to be handled or to the mutual idea of the detecting and control to ongoing execution on limited resources and due to the unpredictability to the huge number of untrustworthy agent present. With the limited measure of data transmission accessible, it is improved to use it ideally and proficiently. This further raises the requirement for need choices issue for controlling a series of actuators for a progression of tasks. The proposed methodology deals broadly made in two distinct directions. The first direction aims at a control theoretical analysis while considering the network as a constant parameter like special controllers and altering the sampling rate. The second direction aims the design of new communication network infrastructures, algorithms or protocols like designing static and dynamic message scheduling algorithms. This method combines both directions and depends on the well- recognized results in both communication networks and control theory


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