Compensation method of NPCCS time-varying and time delay of IMC and SPC

Abstract

The present invention provides a compensation method of NPCCS (Networked parallel cascade control systems) time-varying and time delay of IMC (Internal model control) and SPC (Smith predictor control), belonging to the technical field of single-input and dual-output networking control system with limited bandwidth resources. for the problem that, in the NPCCS, the network time delay generated whentransmission of network data between nodes reduces the control performance quality of the NPCCS and even allow the system to lose stability, a network time delay compensation model is provided for replacing with all the real network data transmission processes in the NPCCS; main and slave closed-loop control circuits are respectively subjected to the IMC based on a controlled object end and the SPC based on the controlled object end; and the measurement, the estimation or the identification of network time delay between the nodes can be eliminated on the system structure so as to reduce the influence of the time-varying time delay on the NPCCS stability, improve the system control performance quality and achieve the compensation and control of the time-varying network time delay.

Description

technical field [0001] A compensation method for time-varying delay of NPCCS (Networked parallel cascade control systems, NPCCS) of IMC (Internal model control, IMC) and SPC (Smith predictor control, SPC), involving technologies such as process control, network communication and computer control Cross-field, especially the technical field of single-input and double-output networked control systems with limited bandwidth resources. Background technique [0002] Cascade control systems (CCS) is an advanced control system widely used in process control engineering. CCS can quickly suppress the disturbance entering the auxiliary 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-loop control loop (Primary closed control loop, PCCL) and a secondary closed-loop control loop (Secondary closed control loop, SCCL). [0003] CCS has two types of control...

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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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