A Time-Delay-Bounded Data Scheduling Algorithm for Delay Reduction in Distributed Networked Control Systems

Abstract

As a key feature of networked control systems (NCSs), the time delays induced by communication medium sharing and data exchange over the system components could largely degrade the NCS performances or may even cause system instability, and thus, it is of critical importance to reduce time delays within NCSs. This paper studies the time-delay reduction problem in distributed NCSs and presents a dual-way data scheduling mechanism for time-delay reductions in delay-bounded NCSs with time-varying delays. We assess the time delays and their influences on the NCSs first with various delay factors being considered and then describe a one-way scheduling mechanism for network-delay reductions in NCSs. Based upon such a method, a dual-way scheduling algorithm is finally proposed for distributed NCSs with different types of transmitted data packets. Experiments are conducted on a remote teaching platform to verify the effectiveness of the proposed dual-way scheduling mechanism. Results demonstrate that, with the stability time-delay bound considered within the scheduling process, the proposed mechanism is effective for NCS time-delay reductions while addressing the stability, control accuracy, and settling time issues efficiently. Such a proposed mechanism could also be implemented together with some other existing control algorithms for time-delay reductions in NCSs. Our work could provide both useful theoretical guidance and application references for stable tracking control of delay-bounded NCSs.

Engineering Emergence: A Survey on Control in the World of Complex Networks

“…They are caused by node processing (stalling task execution), queuing (waiting to access resources), transmission, and propagation (paths through multiple nodes) [81,82]. Moreover, these time delays can be constant, varying, random, and usually difficult, if not impossible, to estimate even though attempts are found throughout the literature [27,[83][84][85][86][87]. Controller designs that account for network-induced delays are also widespread, ranging from formal robust and optimal control, to intelligent and heuristic approaches [88][89][90][91][92][93][94][95].…”

“…The control issues of SoSs apply to CNs, revealing an ever-increasing need for specialized tools and frameworks. As such, control engineering faces challenges related to heterogeneity (pertaining to structure, information, and resource access, communication and interaction methodologies), remote monitoring and control, scalability, geographical distribution (in the case of large-scale systems), flexibility, and configurability [27].…”