NPCCS uncertain network time delay compensation method based on SPC

Abstract

An NPCCS uncertain network time delay compensation method based on SPC belongs to the single-input dual-output networked control system technology field with limited bandwidth resources. In the NPCCS,because of network time delay generated by network data when being transmitted among nodes, the control performance quality of the NPCCS is reduced and a system loses stability. Aiming at the above problems, all real network data transmission processes in the NPCCS are used to replace a network time delay compensation model. SPC based on a controlled object end and the SPC based on a controller end are implemented on primary and secondary closed-loop control loops. The measurement, estimation or identification of the network time delay among the nodes are avoided from a system structure, theinfluence of uncertain network time delay on NPCCS stability is reduced, the control performance quality of the system is improved, and the compensation and control of the uncertain network time delayare realized.

Description

Technical field [0001] A SPC (Smith predictor control, SPC)-based NPCCS (Networked parallelcascade control systems, NPCCS) uncertain network delay compensation method, involving the intersection of process control, network communication and computer control technologies, especially involving limited bandwidth resources Single-input dual-output networked control system technology field. Background technique [0002] Cascade control systems (CCS) is an advanced control system that is widely used in process control engineering. CCS can quickly suppress the disturbance that enters the secondary loop and improve the dynamic performance and anti-interference ability of the closed-loop control system. CCS usually includes two closed-loop control loops, namely a primary closed control loop (PCCL) and a secondary closed control loop (SCCL). [0003] CCS has two types of control system structures: one is the series cascade control system (SCCS) structure; the other is the parallel cascade ...

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Problems solved by technology

[0010] (1) Since network delay is related to factors such as network topology, communication protocol, network load, network bandwidth, and data packet size, for network delays greater than several or even dozens of sampling periods, it is necessary to establish each closed-loop control loop of NPCCS It is currently difficult to accurately predict, estimate or identify mathematical models of network delay in

[0011] (2) In NPCCS, the network delay in the process of transmitting network data from the previous network node to the next network node, no matter what kind of prediction or estimation method is used in the previous node, it is impossible to know the subsequent network delay in advance The exact value of the resulting network delay

Time delay leads to system performance degradation and even system instability, and also brings difficulties to the analysis and design of the control system

[0012] (3) It is unrealistic to completely synchronize the clock signals of all network nodes in different distribution locations in NPCCS

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