Compensation method for unknown network delay of network cascade control system

Abstract

The invention provides a compensation method for unknown network delay of a network cascade control system, belonging to the technical field of network control systems. The method adopts a network data transmission process among all forward and feedback network path nodes of the actual network cascade control system to replace a network delay compensation model thereof, avoids measurement, observation, estimate or identification for unknown delay of network data transmission among the nodes, and also avoids the synchronization requirement on node clock signals. The method can reduce the influence of unknown network delay on stability of the system and improve the control performance quality of the system. The method is suitable for dynamically compensating and controlling unknown network delay in all forward and feedback network paths of network simultaneously existing in the network cascade control system, when mathematical models of main auxiliary controlled objects are known or unknown, the system has unknown interference, and the network exists a certain amount of data packet losses.

Description

technical field [0001] The invention relates to a compensation method for unknown network delay in a network cascade control system, belonging to the technical field of network control systems. Background technique [0002] With the widespread use of computer networks and the continuous development of network technology, the structure of the control system is changing, and networked control systems (NCS) have emerged as the times require. "Networked control systems" refer to the field sensors, control It is a collection of devices, actuators and communication networks to provide data transmission between devices, so that users in different locations in the area can share resources and coordinate operations. It is a fully distributed system that integrates communication networks and control systems. , Networked real-time feedback control system. This networked control mode has the advantages of sharing information resources, reducing the number of connection lines, easy expan...

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Problems solved by technology

[0008] (2) The network delay that occurs in the process of transmitting network data from the previous node to the next node, no matter what prediction or estimation method is used in the previous node, it is impossible to know in advance the subsequent network delay Accurate value. Time delay leads to system performance degradation and even system instability, and also brings difficulties to the analysis and design of the control system.

[0013] Since the denominator of the closed-loop transfer function shown in equation (1) includes the network delay τ 1 and τ 2 , τ 3 and τ 4 index term of and and The existence of time delay will deteriorate the control performance quality of the system, and even cause the system to lose stability, and in severe cases, the system may fail.

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