Aperiodic sampled-data control of distributed networked control systems with time-delay

Author(s):  
Kritika Bansal ◽  
Pankaj Mukhija

This paper proposes a hybrid aperiodic sampled-data mechanism for the control of interconnected subsystems with time-delay. The proposed aperiodic sampled-data mechanism comprises of two stages. In the first stage, the next sampling instant for each subsystem is computed using self-triggering strategy. Thereafter, in the second stage, an event-triggering condition is checked at these sampling instants for each subsystem and signal is transmitted to the controller only if the event-triggering condition is violated. Further, to reduce the computational complexity involved in the proposed triggering mechanism, another triggering mechanism with integrated event-triggering and self-triggering is developed. Also, an upper bound on delay for each subsystem is computed to ensure the stability of distributed networked control system. The results proposed are validated using a simulation example. A comparison of the proposed technique with other triggering mechanisms in terms of sampling instants, number of transmissions to the controller, maximum delay bound and other performance measures is drawn through simulation example.

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.


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.


Author(s):  
Ahmet Kuzu ◽  
Seta Bogosyan ◽  
Metin Gokasan

The performance of networked control systems is affected strictly by time delay. Most of the literature in the area handle the problem from a stability perspective. However, stability optimized algorithms alone are not sufficient to reduce synchronization problems caused by time delay between the action and reaction in geographically distant places, and the effect and performance of other system components should also be taken into account. In teleoperation applications the reference is often provided by a human, known as the operator, and due to the nature of the human system, references provided by the human operator are of a much lower bandwidth when compared to common control reference inputs. This paper focuses on the operator, and proposes an approach to predict the manipulator’s motion (created by the operator) ahead of time with an aim to reduce the time delay between the master and slave manipulator trajectories. To highlight the improvement offered by the developed approach, hereby called Predictive Input Delay Compensator (PIDC), we compare the performance with the only other study in the literature that handles this problem using the Taylor Series approach. The performance of these two approaches is evaluated experimentally for the forward (control) path on a PUMA robot, manipulated by a human operator and it has been demonstrated that the efficient latency in the forward path is decreased by 100ms, on average, reducing the forward latency from 350ms to 250ms.


2008 ◽  
Vol 41 (2) ◽  
pp. 11594-11599 ◽  
Author(s):  
Chih-Chung Chen ◽  
Sandra Hirche ◽  
Martin Buss

2014 ◽  
Vol 556-562 ◽  
pp. 5501-5505 ◽  
Author(s):  
Ping Qian ◽  
Wen Rui Wang ◽  
Xue Qiang Li ◽  
Yin Zhong Ye

For a kind of networked control systems with short time-delay, establish discrete time-invariant system model. Construct the Lyapunov function based on the Lyapunov asymptotic stability principle. Using Linear Matrix Inequalities method given the sufficient condition of H∞ robust controller design method of closed-loop feedback control systems. Matlab simulation indicates the effectiveness and correctness of the controller design.


2014 ◽  
Vol 536-537 ◽  
pp. 1183-1186 ◽  
Author(s):  
Jian Qiu Deng ◽  
Cui Hao

This paper addresses the stabilization and optimization problem of networked control systems (NCSs) with long time delays. According to the actual network conditions, the network time delay is divided into the fixed time delay and the random time delay. Then, the stabilization controller is constructed, where the stabilizing control parameters are obtained with cone complementary linearization (CCL) approach and the optimizing control parameters are solved with estimation of distribution algorithm (EDA) algorithm. Simulation results demonstrate the effectiveness of the proposed methods.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Haitao Zhang ◽  
Jinbo Hu ◽  
Wenshao Bu

We first analyze the effect of network-induced delay on the stability of networked control systems (NCSs). Then, aiming at stochastic characteristics of the time delay, we introduce a new Smith predictor to remove the exponential function with the time delay in the closed-loop characteristic equation of the NCS. Furthermore, we combine the fuzzy PID algorithm with the fuzzy immune control algorithm and present a fuzzy immune self-adaptive PID algorithm to compensate the influence of the model deviation of the controlled object. At last, a kind of fuzzy immune self-adaptive PID algorithm based on new Smith predictor is presented to apply to the NCS. The simulation research on a DC motor is given to show the effectiveness of the proposed algorithm.


2007 ◽  
Vol 6 (5) ◽  
pp. 780-783
Author(s):  
Limin Cheng ◽  
Li Kong ◽  
Changlin Ma ◽  
Xiaoling Zhu

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