Network scheduling algorithm for CAN (controller area network) bus master-slave answer mode protocol

Abstract

The invention discloses a network scheduling algorithm for a CAN (controller area network) bus master-slave answer mode protocol; the network scheduling algorithm is used for message scheduling in a CAN bus network which adopts a master-slave answer mode application protocol for network communication. According to the scheduling algorithm, when a time-triggered scheduling list is created, constraint conditions that requests and answer messages are placed alternately, request messages of the same destination ID are not arranged in adjacent columns of the same row of the scheduling list are adopted for creating the scheduling list in an alternate type bin packing algorithm. A genetic algorithm is improved for optimizing the exclusive time window of the scheduling list, so that the bus use ratio is improved. Node messages in the network are subjected to periodical statistics, the scheduling list is dynamically updated, and reasonable use of resources is realized. According to the scheduling algorithm, the use ratio of network buses can be improved, waiting time lapse of messages can be reduced, messages can be reasonably scheduled, and defects of an existing network scheduling algorithm when a master-slave answer mode is adopted are overcome.

Description

technical field [0001] The invention relates to the field of CAN bus distributed network technology control, more specifically, especially the network scheduling algorithm that adopts the master-slave response mode protocol in the CAN bus network. Background technique [0002] Controller Area Network (CAN) has been widely used in industrial automation, various control equipment, transportation, medical equipment, construction, environmental control, solar charging due to its high performance, high reliability, real-time and other advantages. systems and many other fields. [0003] The traditional CAN bus is essentially an event-triggered mechanism, and the cut-off access adopts the CSMA method. When the bus conflicts in the network, the CAN bus uses a non-destructive arbitration mechanism to arbitrate the priority of the message, and the message with the highest priority gets the bus to send the message . In order to ensure predictable message communication and reduce the ...

AI Technical Summary

Problems solved by technology

[0005] (1) After the master station sends a request message to the slave node, the slave node may delay the response message returned to the master station due to some processing, because the user may combine the request and response information as one piece of information when collecting network information. Scheduling, but in this case, the master station must wait for the slave station, and there is a large waste of time window at this time

[0006] (2) The schedule generated by the traditional box-packing algorithm, because the box-packing algorithm is an NDP (non-deterministic polynomial) problem, that is, it cannot be solved accurately in polynomial time, so the generated schedule is not optimal, which will cause many problems. There is a problem of wasting time units in the allocation of time windows. At this time, the bus is idle and cannot be used for other information transmission.

In response to this situation, genetic algorithm has been used for optimization, but genetic algorithm has some disadvantages

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