Hybrid unidirectional time delay estimation method suitable for network control system

A technology for network control system and time delay estimation, which is applied in industrial automatic control, computer network, and machinery manufacturing automation field, can solve the problems that cannot be directly applied, the one-way time delay estimation of forward and reverse control channels is difficult, and it is difficult to obtain reference standards Quantity and other issues

CN101394324AInactive Publication Date: 2009-03-25WUHAN UNIV OF TECH
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2009-03-25
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a mixed type one-way delay estimation method, which is suitable for a network control system (NCS). The method comprises the following steps: (1) estimating the one-way delay of a start control initial frame sent from an actuator in the NCS by adopting an online measuring method which is based on router delay compositional analysis, so as to obtain a relatively precise estimated value; and (2) respectively estimating through a series of calculations which are based on rebound trip time (RTT) values recorded by local clocks at both ends of the system and use the obtained start control initial frame estimated value as a reference scalar to obtain the one-way delay values in the forward channel and the backward channel of the NCS. The method not only effectively overcomes the oversized system overhead defect of the online estimation method, but also has remarkably improved precision of the estimated value compared with the prior end-to-end one-way delay estimation method, so as to achieve the purpose of effectively and accurately estimating the one-way delay of the NCS.
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Description

technical field

[0001] The invention belongs to the fields of mechanical manufacturing automation, industrial automatic control and computer network, and specifically relates to a hybrid one-way delay estimation method suitable for network control systems. Background technique

[0002] Due to the characteristics of low application cost and high flexibility, computer networks can be widely used in automatic control applications in various industrial fields, such as remote industrial control, production workshop automation, and remote monitoring of equipment. Therefore, in recent years, the Network Control System (NSC), which combines computer network technology and automatic control technology, has gradually attracted people's attention in the industrial field and has been widely used. NCS is a distributed real-time feedback control system composed of sensors, controllers, actuators and communication networks. It can effectively reduce the complexity of system wiring, increa...

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Embodiment Construction

[0081] The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments, but these embodiments should not be construed as limiting the present invention.

[0082] A typical NCS system structure such as figure 1 shown. In the whole system, the delay of message delivery has a significant impact on the stability and control performance of the system. The message delivery delay T of the NCS system delay It mainly consists of three parts, as shown in the following formula:

[0083] T delay = t sc +t p +t ca

[0084] Among them, t ca is the network forward delay, t sc is the network reverse delay, t p is the processing delay of the end system. Since the end system uses a local clock, it is possible to accurately calculate t p value. However, the distribution of each node connected by the network makes it difficult for each node in the NCS system to synchronize clocks, so the time delay t generated by the large...