Modeling and Stability Analysis of Multi-Rate Networked Control Systems with Multiple Control Loops

2010 ◽  
Vol 139-141 ◽  
pp. 1827-1833 ◽  
Author(s):  
Dian Ting Liu ◽  
De Jian Zhou ◽  
Yao Ming Liu
Keyword(s):  
Control System ◽  
Networked Control Systems ◽  
Sampling Period ◽  
Networked Control System ◽  
Network Control ◽  
Networked Control ◽  
Control Loop ◽  
Multiple Control ◽  
Control Loops ◽  
Analysis And Design

A kind of multi-input and multi-output network control system with multiple independent control loops is examined in this paper. The controller of each control loop is connected with the sensor and actuator by a network and each control loop has a different sampling period. The whole mathematical model of this kind of networked control system is set up when the maximum network-induced delay is smaller than one sampling period. And the sufficient condition subject to the asymptotic stability of this kind of networked control system is derived based on the theorem for estimation of feature value deduced from perturbation theory. The research results of this paper have significance in the analysis and design of this kind of networked control system or a similar networked control system.

The Simulation Platform of Network Control System

2012 ◽  
Vol 562-564 ◽  
pp. 1434-1437
Author(s):  
Chen Liang ◽  
Jun Lin
Keyword(s):  
Control System ◽  
Control Systems ◽  
Networked Control Systems ◽  
Networked Control System ◽  
Network Control ◽  
Networked Control ◽  
Control Technique ◽  
Simulation Platform ◽  
Analysis And Design ◽  
Technology Control

With the development of electronic technology, computer and networked communication technology, control system is speeding up from close and centralized architecture to being open and distributed, to satisfy the continuous developing requirement of control quality and management. Networked control system is gradually formed in the process, and soon become one of the most important domains of control technique. One of the research of networked 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. The simulation platform gives good environment for the analysis and design of networked control systems.

scholarly journals ISA 100.11a Networked Control System Based on Link Stability

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5417 ◽  
Author(s):  
Heitor Florencio ◽  
Adrião Dória Neto ◽  
Daniel Martins
Keyword(s):  
Control System ◽  
Control Systems ◽  
Wireless Network ◽  
Networked Control Systems ◽  
Networked Control System ◽  
Network Control ◽  
Networked Control ◽  
Control Loop ◽  
Link Stability ◽  
Tank System

Wireless networked control systems (WNCSs) must ensure that control systems are stable, robust and capable of minimizing the effects of disturbances. Due to the need for a stable and secure WNCS, critical wireless network variables must be taken into account in the design. As wireless networks are composed of several links, factors that indicate the performances of these links can be used to evaluate the communication system in the WNCS. This work presents a wireless network control system composed of ISA 100.11a sensors, a network manager, a controller and a wired actuator. The system controls the liquid level in the tank of the coupled tank system. In order to assess the influence of the sensor link failure on the control loop, the controller calculates the link stability and chooses an alternative link in case of instability in the current link. Preliminary tests of WNCS performance were performed to determine the minimum stability value of the link that generates an error in the control loop. Finally, the tests of the control system based on link stability obtained excellent results. Even with disturbances in the network links, the control system error remained below the threshold.

scholarly journals Design of Multi-Rate Multi-Zone Wireless Fuzzy Temperature Control System for Greenhouse Application

2020 ◽  
Vol 26 (7) ◽  
pp. 97-114
Author(s):  
Qays Jebur Sabr
Keyword(s):  
Control System ◽  
Fuzzy Controller ◽  
Networked Control Systems ◽  
Sampling Rate ◽  
Sampling Period ◽  
Networked Control System ◽  
Networked Control ◽  
Temperature Control System ◽  
Temperature Controller ◽  
Input Gain

sensor sampling rate (SSR) may be an effective and crucial field in networked control systems.  Changing sensor sampling period after designing the networked control system is a critical matter for the stability of the system. In this article, a wireless networked control system with multi-rate sensor sampling is proposed to control the temperature of a multi-zone greenhouse. Here, a behavior based Mamdany fuzzy system is used in three approaches, first is to design the fuzzy temperature controller, second is to design a fuzzy gain selector and third is to design a fuzzy error handler. The main approach of the control system design is to control the input gain of the fuzzy temperature controller depending on the current zone and current sensor rate for each zone. Due to the low input gain of the fuzzy controller, the steady state output error of the greenhouse temperature is in the range (0.55 – 11.22) % when the system using five sensors of different sampling rates and in the range (2.43 - 16.74) % when the system using five sensors with the same sampling rates. Next, after designing the fuzzy error handler, this error doesn’t exceed 1.6%, but in most cases it is less than 0.15%.The work is Simulink designed and implemented using Matlab R2012b. The Zigbee wireless network is proposed for the system, it is implemented in Matlab using True time 2.0 library.

Scheduling method for networked control system with resource constraints based on fuzzy feedback priority and variable sampling period

2016 ◽  
Vol 40 (4) ◽  
pp. 1136-1149 ◽  
Author(s):  
Tian Zhongda ◽  
Li Shujiang ◽  
Wang Yanhong ◽  
Wang Xiangdong
Keyword(s):  
Control System ◽  
Data Transmission ◽  
Resource Constraints ◽  
Sampling Period ◽  
Networked Control System ◽  
Networked Control ◽  
Control Loop ◽  
Network Utilization ◽  
Variable Sampling ◽  
Scheduling Method

A scheduling method based on fuzzy feedback priority and variable sampling period for a networked control system with resource constraints is proposed in this paper. Firstly, each control loop weight is adjusted dynamically according to a control loop data transmission error through a quadratic square root mapping function. A different weight is given for each loop. A fuzzy feedback priority scheduling strategy is designed combined with dynamic weight, system output and system output error rate. The priority of each control loop is adjusted dynamically. Then, considering the current network status, the new network utilization is predicted through proportional control. A least-squares support vector machine (LSSVM) algorithm is used for controlled loop packet transmission time prediction. A variable sampling period for each control loop is determined by using a controlled loop dynamic weight, network utilization and data transmission time. Finally, a fuzzy feedback priority scheduler and variable sampling period scheduler are combined. The merits of the two schedulers are utilized to achieve the optimization goal. A simulation experiment is carried out using the True Time toolbox. Simulation results show that the scheduling method can make the network utilization rate converge to the desired value under resource constraints, improve the output response performance of the control loop, reduce the integral absolute error value of the control loop and decrease the data transmission time of the control loop. The networked control system performance is improved and the scheduling method of this paper is effective.

Deadband feedback-based scheduling approach for networked control system with variable sampling period

2021 ◽  
pp. 014233122098142
Author(s):  
Zhongda Tian
Keyword(s):  
Control System ◽  
Sampling Period ◽  
Networked Control System ◽  
Networked Control ◽  
Control Performance ◽  
Control Loops ◽  
Network Bandwidth ◽  
Network Utilization ◽  
Variable Sampling ◽  
Overall Performance

Reasonable information scheduling strategies in the networked control system (NCS) can improve the quality of service of the network, reduce the conflict of information transmission in the network, and improve the overall performance of the NCS. In order to improve the performance of the NCS, a deadband feedback-based scheduling approach for the NCS with a variable sampling period is proposed. For the NCS with multi control loops, considering the limitation of network bandwidth resources, the dynamic real-time adjustment of a multi-loop sampling period is achieved through network utilization prediction, network bandwidth configuration and sampling period calculation. Furthermore, deadband feedback scheduling is combined with a variable sampling period algorithm. Deadband is set in the sensor and controller nodes to effectively adjust the information flow of the forward channel and the feedback channel. The proposed scheduling approach can reduce the impact of network conflict and network delay on system stability, make the network resources allocated reasonably, save network data traffic, and improve the overall performance of the NCS. A NCS with five control loops is used as the simulation object and carried out by True Time toolbox. The simulation results show that the proposed scheduling approach can improve output control performance of the system, reduce integral absolute error value of the control loops, and improve network utilization. The overall control performance of the system is improved.

Perturbations in Networked Control Systems

2001 ◽  
Author(s):  
Octavian Beldiman ◽  
Linda G. Bushnell ◽  
Gregory C. Walsh ◽  
Hua O. Wang ◽  
Yiguang Hong
Keyword(s):  
Control System ◽  
Control Systems ◽  
Networked Control Systems ◽  
Networked Control System ◽  
Networked Control ◽  
Asymptotically Stable ◽  
Networked System ◽  
External Perturbations ◽  
Exponentially Stable

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.

Research on Stability of Networked Control System with Uncertain Time-Varying Delays

2011 ◽  
Vol 383-390 ◽  
pp. 2138-2144
Author(s):  
Wei Hao Ma ◽  
Chao Yong Jin
Keyword(s):  
Control System ◽  
Sampling Period ◽  
Networked Control System ◽  
Networked Control ◽  
Sufficient Condition ◽  
Time Varying ◽  
Matrix Inequalities ◽  
Time Varying Delay ◽  
Uncertain Time ◽  
Varying Delay

This note deals with the problem of stability for networked control system (NCS) with uncertain time-varying delay that is less than on sampling period. A new stability scheme was proposed. Using an Lyapunov function, less conservative stability sufficient condition was derived for such system based on liner matrix inequalities (LMs). Finally a numerical example shows the superiority of the method in this paper.

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