ISSN 2630-0583 (Print)

ISSN 2630-0656 (Online)


Journal of Current Science and Technology

Rangsit Journal of Arts and Sciences. Vol.5 No.2 , July - December 2015.

Robust control of networked control systems with randomly varying time-delays based on adaptive Smith predictor

Xuan-Kien Dang, Van-Thu Nguyen, and Xuan-Phuong Nguyen


           In this paper, we deal with the robust control of network induced delay and randomly varying time-delay (RVTD) controlled plant in networked control systems (NCS).  The control problem of NCS becomes more challenging to attain the robust stability when time-delay appears in form of a time-varying signal in the closed loop of NCS.  These in turn make the conventional control methods, e.g., normal mathematical model of Smith predictor, more complicated to meet the quality requirements of NCS.  To overcome these inherent challenges, we essentially analyzed the existing techniques, and then propose a novel adaptive Smith predictor to efficiently reduce the effect of time-delays for high efficient and accurate control.  Hence, the delay-dependent NCS becomes the delay-independent NCS, we proposed a necessary and sufficient conditions for the robust stability and performance of NCS in general formulation.  By using the H∞ loop-shaping - McFarlane and Glover controller design method based on co-prime factor robustness and Linear Matrix Inequality (LMI), a robust controller has been suggested.  The simulation results via TrueTime Beta2.0 platform demonstrate the usefulness and effectiveness of the proposed method.

Keywords: networked control system, neural networks, adaptive Smith predictor, time-delay estimation, robust controller, Linear Matrix Inequality.

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