CN116155834A - Deterministic resource scheduling method for industrial Internet of things heterogeneous data - Google Patents

Abstract

The invention discloses a deterministic resource scheduling method for industrial Internet of things heterogeneous data, and belongs to the field of industrial Internet of things. The method is characterized in that the network communication resources are uniformly configured by introducing a new industrial broadband bus AUTBUS, so that the communication efficiency and the communication accuracy are improved. The method of the invention takes a production assembly line as a research object, and divides a time frame into a fixed time slot part and a dynamic time slot part. The method adopts fixed time slot communication to the nodes existing in the control system, and corresponds to the production flow of an assembly line; the added nodes are communicated by dynamic time slots, after the communication is stable, the added nodes are transferred into fixed time slots, and then the fixed time slots are allocated again; if the original node is deleted, the fixed time slot is reassigned, so that the design is more fit to reality. The invention satisfies the periodic sampling characteristic of the factory control system and realizes the deterministic, reliable and real-time transmission of data; and meanwhile, the flexibility and the expandability of the communication network in industrial production are improved.

Description

Deterministic resource scheduling method for industrial Internet of things heterogeneous data

Technical Field

The invention belongs to the field of industrial Internet of things, and particularly relates to a scheduling method for deterministic resources of industrial Internet of things heterogeneous data.

Background

The industrial Internet of things can integrate the technologies of intelligent analysis, mobile communication and the like into each link of industrial production, so that the manufacturing efficiency is greatly improved, the product quality is improved, and the traditional industry is finally improved to an intelligent new stage. The industrial Internet of things is widely applied to the fields of safety monitoring, intelligent transportation, environmental monitoring and the like. However, as research continues to be in progress, industrial buses in the field are increasing, and the types of buses are also becoming more and more complex. There are currently about 40 industrial fieldbuses worldwide, and common industrial FieldBus technologies are FieldBus (FF), CAN bus, 485 bus, standard ethernet, etc., which are of a wide variety and non-uniform. With the development of technology, the conventional industrial field bus cannot meet the production requirement. Modern production requires that a new generation of measurement and control network in an industrial site has the capabilities of intelligence, convenience, multiple nodes, real-time, multiple services and the like.

Various networks are integrated in the same factory, the time synchronization precision of each network is different, unified planning management is difficult, and real-time and accurate transmission of various data cannot be ensured. In response to the above needs, a new generation of industrial broadband bus AUTBUS (Automation field Bus, AUTBUS) was derived. By introducing AUTBUS, the network communication resource can be managed uniformly, and the periodic sampling characteristic of a factory control system is met, so that the data certainty, reliability and real-time transmission are realized.

The AUTBUS protocol stack model comprises a physical layer, a data link layer and an application layer, wherein a medium access control (Medium Access Control, MAC) layer is positioned at the data link layer, and is one of key protocols for ensuring efficient communication of a network. The MAC protocol determines the mode of accessing the channel by the nodes, coordinates the limited communication resources of the shared channel of a plurality of nodes in the network, and aims to ensure the communication efficiency and the communication accuracy in the channel, avoid the conflict, reduce the energy consumption as much as possible and directly affect the overall performance of the network. Currently, MAC protocols are classified into a contention type, a scheduling type, and a hybrid type according to different access modes of node channels.

At present, the scheduling control cost is low, the allocation of channel resources is relatively fair, but the network expansibility is relatively poor, and the energy waste is easy to cause at low load; the competition type complexity is low, but the conflict is frequent and the energy consumption is easy to increase under high load; the hybrid type network dynamic change can be more suitable for the network dynamic change and the access time delay is reduced, but the design complexity is high and the operation cost is larger.

In industrial production, in order to ensure the production to be fast, efficient and safe, fixed procedures and operations, namely production assembly lines, are mostly adopted. Each production unit of the assembly line only focuses on the work of processing a certain segment, so as to improve the work efficiency and the yield. Therefore, it is very necessary to design a reasonable resource allocation method in combination with industrial production practice.

Disclosure of Invention

Aiming at the problems of various field buses in the industrial Internet of things, inaccurate data transmission, unstable network communication and the like, the invention discloses a deterministic resource scheduling method for heterogeneous data of the industrial Internet of things, which adjusts and distributes communication time slots of a network based on the states of nodes in the network and ensures real-time accurate data transmission.

The technical scheme adopted by the invention for achieving the purpose is as follows: a method of deterministic resource scheduling, comprising the steps of:

(1) The first stage: allocating a fixed time slot for an originally existing node in the system;

(2) And a second stage: if the number of nodes changes, the time slots are reassigned according to the specific situation.

The (1) first stage: the method for allocating the fixed time slot to the node originally existing in the system comprises the following implementation steps:

step one: detecting the current node number m in a field communication network;

step two: predicting the data quantity of the node, and judging the time slot quantity used by the data transmission of the node;

step three: the nodes are assigned time slots which remain as uniform as possible within a time frame.

Step three, allocating time slots for the nodes, wherein the allocated time slots are kept as uniform as possible in a time frame, and the method comprises the following steps:

each time frame structure is fixed, and S time slots are shared, wherein one part of the time slots is occupied by the system; each time slot is marked as I in sequence _i (i=1, 2,) S, provided that there are L available communication slots (L<S), the time slots required by each node are different, and the total number of the communication time slots of all the nodes is set as n (n)<L<S), the interval between each node (referring to the interval between the last slot of the previous node and the first slot of the next node) is D (D>0) If the division cannot be completed, rounding the D downwards;

let the time slot allocated by the node be A _i The time slot with small serial number allocated to the node is called (A) according to the different time slots allocated to the data volume of the node _i ) _min The sequence number is larger than (A _i ) _max The time slot sequence relationship allocated among the nodes is that

(A _i ) _min ＝(A _i-1 ) _max +D+1。

The (2) second stage: if the number of nodes changes, reallocating the time slots according to specific conditions, including the following implementation steps:

step one: if the number of nodes is reduced, namely m is reduced, n is reduced and L is increased, the node interval D needs to be recalculated, and the available communication time slot L is reassigned;

step two: if the number of the nodes is increased, namely m is increased, n is increased and L is decreased, the competition time slot is used for communication for the increased part of nodes, and the original node still uses a fixed time slot; and after the communication of the competition time slot part is stable, switching the added nodes into the fixed time slot part, and reallocating the fixed time slots.

The second step is as follows: if the number of the nodes is increased, namely m is increased, n is increased and L is decreased, the competition time slot is used for communication for the increased part of nodes, and the original node still uses a fixed time slot; after the communication of the competition time slot part is stable, the added node is transferred to the fixed time slot part to reallocate the fixed time slot, and the method comprises the following implementation steps:

step one: before transmitting data, the node detects whether a channel is idle and available;

step two: waiting if the channel is occupied; transmitting data if the channel is idle;

step three: while transmitting data, the node continues to monitor the network to avoid collisions. If two or more nodes detect that the channel is idle at the same time and transmit data at nearly the same time, a collision may occur;

step four: when a node detects a conflict, immediately stopping data transmission and sending out a congestion signal so as to ensure that other nodes can find the conflict;

step five: after receiving the congestion signal, the other nodes stop transmitting, wait for a randomly generated time interval (back-off time), and then resend the nodes needing to send data.

The invention has the following advantages and beneficial effects:

aiming at the problems that the existing field industrial buses are various in variety, the traditional measurement and control network cannot meet higher requirements and the like, the invention uniformly configures network communication resources by introducing a new industrial broadband bus AUTBUS, thereby improving communication efficiency and communication accuracy.

The deterministic resource scheduling method provided by the invention can ensure fairness of channel allocation resources and avoid mutual interference between nodes by dividing the time slot into a fixed time slot part and a competing time slot part, and simultaneously improves the expandability of the network to a certain extent and the utilization rate of the channel, thereby improving the stability of the network.

Drawings

FIG. 1 is a diagram of a new generation of industrial production architecture;

FIG. 2 is a schematic diagram of a time slot allocation for a node to communicate;

FIG. 3 is a schematic diagram of time slot allocation for communication by multiple nodes;

fig. 4 is a transition relationship between fixed and competing slots in deterministic resource scheduling.

Detailed Description

The main idea of the invention is that: aiming at the problems that the existing field industrial buses are various, the traditional measurement and control network cannot meet higher requirements, and the like, the novel industrial broadband bus AUTBUS (Automation field Bus, AUTBUS) is introduced to uniformly configure network communication resources, so that the communication efficiency and the communication accuracy are improved, and a novel industrial production structure is formed. The new generation of industrial production architecture is shown in figure 1.

The new generation industrial production architecture is a flattened network architecture of the industrial Internet of things compatible with the PLC and the DCS and combined with the AUTBUS, and consists of AUTBUS field devices, TSN (Time-Sensitive Network, TSN) switching devices, a control cloud platform containing the AUTBUS control devices, a business cloud platform, an external public cloud or enterprise cloud and the like.

The AUTBUS field device collects data with different field structures and different sources and transmits the collected data to the TSN switching device. The TSN switching equipment processes the received data, synchronizes the data clock through time calibration, sorts the data in sampling period, and finally sends the processed data to the control cloud platform through an AUTBUS bus. The control cloud platform mainly comprises AUTBUS control equipment, and further comprises a physical server, a virtual management server, an antivirus server and the like. The AUTBUS control equipment receives the data processed by the TSN, and configures communication resources of the network according to the data quantity, the instantaneity and the like so as to ensure that the data in the network can be timely and accurately transmitted. Meanwhile, the control cloud platform can upload data to the business cloud platform, and a user can view the data online to know the site condition so as to realize remote monitoring. The enterprise can upload data to an external public cloud or enterprise cloud platform according to the actual requirements of data sharing and the like, so that the data can be mutually transmitted and the resource sharing is realized.

The method of the invention takes a production assembly line as a research object, and divides a time frame into a fixed time slot part and a dynamic time slot part. The method adopts fixed time slot communication to the nodes existing in the control system, and corresponds to the production flow of an assembly line; the added nodes are communicated by dynamic time slots, after the communication is stable, the added nodes are transferred into fixed time slots, and then the fixed time slots are allocated again; if the original node is pruned, the fixed time slot is reassigned. Thus, once the production flow is changed, the dynamic time slot can be used for processing, and the expansibility of the network is improved.

The present invention will be described in further detail below.

Dividing the channel into channel frames from the time domain, wherein the length of each channel frame is equal; and dividing the channel frame into a plurality of time slots, wherein the lengths of the time slots are equal, and marking the time slot sequence of each frame. Then dividing the time slot into a fixed time slot and a competition time slot, and communicating the nodes in the communication network by using the fixed time slot; once the node changes, the time slots are reassigned for different cases of node addition and deletion. The specific time slot allocation method is shown in fig. 2 and 3.

The (1) first stage: the method for allocating the fixed time slot to the node originally existing in the system comprises the following implementation steps:

step one: detecting the current node number m in a field communication network;

step two: predicting the data quantity of the node, and judging the time slot quantity used by the data transmission of the node;

step three: the nodes are assigned time slots which remain as uniform as possible within a time frame.

Step three, allocating time slots for the nodes, wherein the allocated time slots are kept as uniform as possible in a time frame, and the method comprises the following steps:

each time frame structure is fixed, and S time slots are total, and a part of the time slots are occupied by the system. Each time slot is marked as I in sequence _i (i=1, 2,) S, provided that there are L available communication slots (L<S), the time slots required by each node are different, and the total number of the communication time slots of all the nodes is set as n (n)<L<S), each inter-node interval (referring to the last slot and the last slot of the previous nodeThe interval between the first time slots of the latter node) is D (D>0) If the division cannot be completed, rounding the D downwards;

let the time slot allocated by the node be A _i The time slot with small serial number allocated to the node is called (A) according to the different time slots allocated to the data volume of the node _i ) _min The sequence number is larger than (A _i ) _max . The time slot sequence relationship allocated between the nodes is that

(A _i ) _min ＝(A _i-1 ) _max +D+1。

The schematic diagrams are shown in fig. 2 (m=1) and fig. 3 (m > 1).

The (2) second stage: if the number of nodes changes, reallocating the time slots according to specific conditions, including the following implementation steps:

step one: if the number of nodes is reduced, namely m is reduced, n is reduced and L is increased, the node interval D needs to be recalculated, and the available communication time slot L is reassigned;

step two: if the number of the nodes is increased, namely m is increased, n is increased and L is decreased, the competition time slot is used for communication for the increased part of nodes, and the original node still uses a fixed time slot; and after the communication of the competition time slot part is stable, switching the added nodes into the fixed time slot part, and reallocating the fixed time slots. The specific flow is shown in fig. 4.

The fixed slot reassignment is the same as described in the first stage of (1). The competition time slot implementation steps are as follows:

step one: before transmitting data, the node detects whether a channel is idle and available;

step two: waiting if the channel is occupied; transmitting data if the channel is idle;

step three: while transmitting data, the node continues to monitor the network to avoid collisions. If two or more nodes detect that the channel is idle at the same time and transmit data at nearly the same time, a collision may occur;

step four: when a node detects a conflict, immediately stopping data transmission and sending out a congestion signal so as to ensure that other nodes can find the conflict;

step five: after receiving the congestion signal, other nodes stop transmitting, and after waiting for a randomly generated time gap, the nodes needing to transmit data retransmit.

Summarizing: in the available time slots, the data quantity of each node is pre-estimated in advance, the time slots required by the whole communication are judged, and then reasonable time slot intervals are calculated, so that the time slots of each frame are distributed uniformly as much as possible, and stable transmission of network data is ensured. The fixed time slot and the competitive time slot are combined, so that the mutual interference between nodes is avoided, the adaptability of the network is improved, and the method is tightly combined with field production.

The invention satisfies the periodic sampling characteristic of the factory control system and realizes the deterministic, reliable and real-time transmission of data; and meanwhile, the flexibility and the expandability of the communication network in industrial production are improved.

Claims (5)

1. A deterministic resource scheduling method for industrial Internet of things heterogeneous data is characterized in that: the scheduling method comprises the following steps:

(1) The first stage: allocating a fixed time slot for an originally existing node in the system;

(2) And a second stage: if the number of nodes changes, the time slots are reassigned according to the specific situation.

2. The industrial internet of things heterogeneous data deterministic resource scheduling method according to claim 1, wherein the method comprises the following steps: the (1) first stage: the method for allocating the fixed time slot to the node originally existing in the system comprises the following implementation steps:

step one: detecting the current node number m in a field communication network;

step two: predicting the data quantity of the node, and judging the time slot quantity used by the data transmission of the node;

step three: the nodes are assigned time slots which remain as uniform as possible within a time frame.

3. The industrial internet of things heterogeneous data deterministic resource scheduling method according to claim 2, wherein the method is characterized by comprising the following steps of: step three: the method comprises the steps of allocating time slots to nodes, wherein the allocated time slots are kept as uniform as possible in a time frame, and the method comprises the following steps of:

each time frame structure is fixed, and S time slots are shared, wherein one part of the time slots is occupied by the system; each time slot is marked as I in sequence _i (i=1, 2,) S, provided that there are L available communication slots (L<S), the time slots required by each node are different, and the total number of the communication time slots of all the nodes is set as n (n)<L<S), the interval between each node means the interval between the last time slot of the previous node and the first time slot of the next node, which is D (D>0) If the division cannot be completed, rounding the D downwards;

let the time slot allocated by the node be A _i The time slot with small serial number allocated to the node is called (A) according to the different time slots allocated to the data volume of the node _i ) _min The sequence number is larger than (A _i ) _max The time slot sequence relationship allocated between the nodes is:

(A _i ) _min ＝(A _i-1 ) _max +D+1。

4. the industrial internet of things heterogeneous deterministic resource scheduling method according to claim 1, wherein the method comprises the following steps: the (2) second stage: if the number of nodes changes, reallocating the time slots according to specific conditions, including the following implementation steps:

step one: if the number of nodes is reduced, namely m is reduced, n is reduced and L is increased, the node interval D needs to be recalculated, and the available communication time slot L is reassigned;

step two: if the number of the nodes is increased, namely m is increased, n is increased and L is decreased, the competition time slot is used for communication for the increased part of nodes, and the original node still uses a fixed time slot; and after the communication of the competition time slot part is stable, switching the added nodes into the fixed time slot part, and reallocating the fixed time slots.

5. The industrial internet of things heterogeneous data deterministic resource scheduling method according to claim 4, wherein the method comprises the following steps: step two: if the number of the nodes is increased, namely m is increased, n is increased and L is decreased, the competition time slot is used for communication for the increased part of nodes, and the original node still uses a fixed time slot; after the communication of the competition time slot part is stable, the added node is transferred to the fixed time slot part to reallocate the fixed time slot, and the method comprises the following implementation steps:

step one: before transmitting data, the node detects whether a channel is idle and available;

step two: waiting if the channel is occupied; transmitting data if the channel is idle;

step three: while transmitting data, the node continues to monitor the network to avoid collisions. If two or more nodes detect that the channel is idle at the same time and transmit data at nearly the same time, a collision may occur;

step four: when a node detects a conflict, immediately stopping data transmission and sending out a congestion signal so as to ensure that other nodes can find the conflict;

step five: after receiving the congestion signal, other nodes stop transmitting, and after waiting for a randomly generated time gap, the nodes needing to transmit data retransmit.

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