CN-122018473-A - Distributed sequential logic conflict resolution method for distributed control system

CN122018473ACN 122018473 ACN122018473 ACN 122018473ACN-122018473-A

Abstract

The invention discloses a distributed time sequence logic conflict resolution method for a distributed control system, which relates to the technical field of automatic control, and can accurately calculate queuing retention time of an instruction in a network by collecting real-time load and identification of each network node in an instruction transmission path, and correct a local clock of a controller with high precision by combining link basic transmission time delay, so that the real time sequence relation of the instruction is restored, and the interference of clock asynchronism and network delay fluctuation on time sequence judgment in the distributed system is fundamentally eliminated; meanwhile, based on a physical constraint model with self-adaption of real-time working conditions, the theoretical duration required by the state change of the equipment is quantized, the corrected clock difference value and the theoretical duration are dynamically matched, a causal instruction can be effectively distinguished from a physical layer, and the accuracy and the reliability of conflict resolution are remarkably improved.

Inventors

ZHOU LIANG
LI JINLONG
WAN YOUMING
LIU GENPING
ZHANG HAIRUI

Assignees

南京和邦能源科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260408

Claims (10)

1. A distributed sequential logic conflict resolution method for a distributed control system is characterized by comprising the following steps: The method comprises the steps of acquiring a first conflict instruction and a second conflict instruction which are respectively sent by a first controller and a second controller when time sequences conflict, wherein the first conflict instruction comprises a first characteristic pair formed by a first local clock stamp and a first physical characteristic parameter and a first forwarding trace set; Calculating a first retention time and a second retention time of the first conflict instruction and the second conflict instruction in network transmission according to the first forwarding trace set and the second forwarding trace set; correcting the first local clock stamp and the second local clock stamp by using the first retention time length and the second retention time length respectively to obtain a first correction clock and a second correction clock; inputting the first physical characteristic parameter and the second physical characteristic parameter into a physical constraint model, and obtaining a first theoretical duration required by converting the first physical characteristic parameter into the second physical characteristic parameter, and a second theoretical duration required by converting the second physical characteristic parameter into the first physical characteristic parameter; Calculating clock difference values of the first correction clock and the second correction clock, matching the clock difference values with the first theoretical duration and the second theoretical duration, and selecting a reserved instruction as a conflict resolution result according to a causal sequence to output.
2. The distributed sequential logic conflict resolution method for a distributed control system of claim 1, wherein when passing through a first network node, said first network node collects its current first network node load data, current first network node local timestamp and first network node identifier, and adds the three as a first network node forwarding trace to the first conflict command to generate a first intermediate command; When the first intermediate instruction passes through the second network node, the second network node collects current second network node load data, a current second network node local time stamp and a second network node identifier, and combines the current second network node load data, the current second network node local time stamp and the second network node identifier as second network node forwarding traces to be added into the first intermediate instruction, so as to generate a first conflict instruction carrying a first characteristic pair and a first forwarding trace set formed by the first network node forwarding traces and the second network node forwarding traces; the conflict resolver receives the first conflict instruction, records a local receiving time stamp, and extracts a first feature pair and the first forwarding trace set from the first conflict instruction.
3. The distributed sequential logic conflict resolution method for a distributed control system of claim 2, wherein the step of executing a second conflict instruction issued by said second controller symmetrically to said first conflict instruction results in a second feature pair, a second forwarding trace set, and a corresponding local receive timestamp.
4. The distributed sequential logic conflict resolution method for a distributed control system of claim 3, wherein the conflict resolver resolves the first forwarding trace set, extracts a first network node load sequence and a corresponding first network node identification sequence arranged in forwarding order therefrom; reading service rate parameters corresponding to each network node and the sum of transmission delays of each section of network link from a system configuration database, and taking the sum as basic transmission delay; And determining queuing delay of the first conflict instruction at each forwarding network node by utilizing the service rate parameters of each network node according to the first network node load sequence and the corresponding first network node identification sequence, accumulating all queuing delay to obtain a first detention duration, and similarly, determining a second detention duration according to the second network node load sequence and the corresponding second network node identification sequence.
5. The distributed sequential logic collision resolution method for a distributed control system of claim 4, wherein adding a first residence time length to a base transmission time delay to obtain a first total transmission time length; And similarly, adding the second retention time length and the basic transmission time delay to obtain a second total transmission time length, and subtracting the second total transmission time length from the second local receiving time stamp to obtain a second correction clock.
6. The distributed sequential logic conflict resolution method for a distributed control system of claim 5, wherein target equipment history operating condition data at corresponding moments are extracted from a history database according to a first local clock stamp in a first conflict instruction and a second local clock stamp in a second conflict instruction respectively to form a first operating condition parameter set and a second operating condition parameter set; If the data of the accurate corresponding moment does not exist in the historical database, acquiring by adopting a linear interpolation or nearest neighbor interpolation method; Weighted average is carried out on the first working condition parameter set and the second working condition parameter set to obtain a current working condition parameter set; The method comprises the steps of taking a first physical characteristic parameter as an initial state value, taking a second physical characteristic parameter as a target state value, and inputting a current working condition parameter set into a device state transition time length calculation model, wherein the device state transition time length calculation model predicts a device dynamic characteristic parameter at the current moment on line according to the current working condition parameter set, and determines a first theoretical time length required by changing from the initial state value to the target state value based on the device dynamic characteristic parameter; Exchanging the initial state value and the target state value, taking the second physical characteristic parameter as a new initial state value, taking the first physical characteristic parameter as a new target state value, keeping the current working condition parameter set unchanged, and inputting the current working condition parameter set into the equipment state transition time length calculation model to obtain a second theoretical time length.
7. The method for resolving distributed time sequence logic conflict in a distributed control system according to claim 6, wherein the equipment state transition time length calculation model is a first-order inertia plus pure hysteresis model, model parameters are corrected on line according to a current working condition parameter set, and theoretical time length required for changing from a starting state value to a target state value is calculated based on a step response reverse push principle.
8. The distributed sequential logic conflict resolution method for a distributed control system of claim 7, wherein the conflict resolver calculates a clock difference between the first modified clock and the second modified clock; Obtaining the predicted deviation data of the equipment state transition time length calculation model in the historical conflict resolution cases, and determining a model predicted error range according to the statistical distribution of the predicted deviation data; Synthesizing the network delay fluctuation range and the model prediction error range to obtain a current uncertainty tolerance interval; And judging whether the clock difference value falls into the uncertainty tolerance interval taking the first theoretical duration as a reference, if so, determining that the first theoretical duration is matched, and if so, determining that the second theoretical duration is matched.
9. The distributed sequential logic conflict resolution method for a distributed control system of claim 8, wherein the causal order is determined based on a match result: If only the first theoretical duration is matched, judging that the first conflict instruction is the cause and the second conflict instruction is the result; if only the second theoretical duration is matched, judging that the second conflict instruction is the cause and the first conflict instruction is the result, and if the first theoretical duration and the second theoretical duration are matched or are not matched, switching to dynamic criticality evaluation; and outputting the reserved instruction selected according to the causal sequence judgment or the dynamic criticality evaluation to an execution mechanism of the distributed control system as a conflict resolution result.
10. The distributed sequential logic conflict resolution method for a distributed control system of claim 9, wherein said dynamic criticality evaluation comprises: Acquiring current real-time working condition data of target equipment, wherein the real-time working condition data at least comprises a load rate, a medium temperature and a wear coefficient; respectively evaluating the criticality degree of the first conflict instruction and the second conflict instruction according to the real-time working condition data; the criticality degree is determined by analyzing the deviation degree of a first physical characteristic parameter or a second physical characteristic parameter related to the instruction relative to a safety boundary under the current working condition, the emergency degree of the action represented by the instruction and the response sensitivity of the current health state of the equipment to the instruction execution; comparing the first conflict instruction and the second conflict instruction according to the sequence of the priority of the deviation degree, the second degree of urgency and the last response sensitivity, selecting the instruction with high priority as the reservation instruction, and randomly selecting one of the instructions as the reservation instruction if all the indexes are the same.

Description

Distributed sequential logic conflict resolution method for distributed control system Technical Field The invention relates to the technical field of automatic control, in particular to a distributed time sequence logic conflict resolution method for a distributed control system. Background The distributed control system (Distributed Control System, DCS) is a core infrastructure in the field of modern industrial automation and is widely applied to continuous production processes such as petrochemical industry, electric power energy, metallurgical manufacturing and the like. DCS is typically made up of a plurality of controllers, field devices, and a communication network, each of which independently collects field data and generates control commands that are transmitted to an actuator via an industrial network. Along with the expansion of the scale of an industrial system and the complicating of control tasks, the cooperative work of multiple controllers has become normal, but the problem of command timing conflict is caused by the fact that when two or more controllers send commands to the same target equipment or associated equipment, if the arrival time and the execution sequence of the commands do not meet the process logic requirements, equipment malfunction, production efficiency reduction and even safety accidents may be caused. In order to solve the problem of time sequence conflict, the prior art mainly expands and researches from the following directions that firstly, a global clock synchronization protocol (such as IEEE 1588 PTP) is adopted to carry out high-precision time synchronization on all controllers, so that a conflict resolution device can directly compare local time stamps carried by instructions to judge the sequence, secondly, a priority arbitration mechanism is introduced, static priorities are preset for different controllers or instruction types, high-priority instructions are reserved during conflict, thirdly, a network delay compensation method is adopted, and rough correction is carried out on the instruction time stamps through measuring network average delay or adopting fixed compensation values. However, the above-described technique has many limitations in practical applications. The existing global clock synchronization scheme requires that all controllers and network devices support a precise time protocol, has high hardware cost and is sensitive to a network topology structure, and long-term stability is difficult to ensure in a complex electromagnetic environment of an industrial field. Static priority arbitration mechanisms lack flexibility and cannot accommodate operating condition changes, which can lead to serious consequences when low priority instructions involve emergency safety actions. The method based on fixed delay compensation ignores dynamic fluctuation of network load, queuing delay is simply averaged as a main component of transmission delay, and a significant deviation exists between the corrected clock and the actual sending time. More importantly, the method does not consider the time required by the physical process corresponding to the instruction, namely in industrial control, the dynamic response process (such as valve opening change, temperature rise and the like) of the equipment is needed to be carried out from the sending of an instruction to the appearance of the effect, and the basic error of causal judgment can be caused by neglecting the physical constraint, for example, the emergency shutdown instruction sent later is misjudged as a result, and the dangerous start instruction sent earlier is misjudged as a result, so that accidents are caused. Disclosure of Invention This section is intended to summarize some aspects of embodiments of the application and to briefly introduce some preferred embodiments, which may be simplified or omitted in this section, as well as the description abstract and the title of the application, to avoid obscuring the objects of this section, description abstract and the title of the application, which is not intended to limit the scope of this application. The present invention has been made in view of the above-described problems occurring in the prior art. Therefore, the invention solves the technical problem of how to provide a distributed time sequence logic conflict resolution method which can accurately correct network transmission delay, fuse physical dynamic characteristics of equipment and reasonably decide when time sequence is fuzzy. The distributed time sequence logic conflict resolution method for the distributed control system is characterized by comprising the steps of obtaining a first conflict instruction and a second conflict instruction which are respectively sent out by a first controller and a second controller when time sequence conflicts, wherein the first conflict instruction comprises a first characteristic pair formed by a first local clock stamp and a first physical characteristic para