Redundant CAN Packet Reception for ATO Sequence Verification
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Solution Overview
Problem
Existing Automatic Train Operation (ATO) systems using redundant CAN buses face issues with data reliability due to abnormal cases like repeated packet transmission, packet loss, or inability to receive data when packet counts are equal, leading to logical problems.
Innovation Solution
A method and device for ATO systems that utilize redundant CAN channels by comparing packet counts and sequence numbers to classify and store data in FIFOs, ensuring reliable data reception by identifying and utilizing the trusted channel based on packet differences and sequence number verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant CAN buses are used for data transmission, then data reliability is improved, but logical problems occur due to duplicate packets, packet loss, or inability to receive data when packet counts are equal
Solution Approach 1:
The patent implements a feedback mechanism by comparing sequence numbers of received packets from redundant CAN buses. The receiving end monitors packet sequence numbers and provides feedback to determine which channel is transmitting correctly, enabling dynamic adjustment of data reception strategy based on actual transmission status.
Solution Approach 2:
The patent introduces sequence number comparison as an intermediary mechanism between the redundant CAN channels and the data processing system. This intermediary compares sequence numbers to identify the trusted channel, preventing logical problems caused by direct reception from multiple redundant sources.
2Reliability
If data from the CAN bus with greater packet count is received, then duplicate packets are avoided in normal cases, but logical problems occur when packet transmission is abnormal
Solution Approach 1:
The patent replaces the mechanical approach of simply comparing packet counts with a more sophisticated sequence number verification system. Instead of relying on quantity-based selection, the system uses sequence number validation to identify the correct data source, substituting a more intelligent verification mechanism.
Solution Approach 2:
The system continuously monitors sequence numbers and provides feedback to determine channel trustworthiness. When sequence numbers indicate abnormal transmission (duplicates or losses), the feedback mechanism triggers a switch to the other redundant channel, maintaining reliable data reception.
3Reliability
If data from the CAN bus with smaller packet count is received, then duplicate packets are avoided, but packet loss occurs when that bus experiences transmission issues
Solution Approach 1:
The patent uses sequence number feedback to monitor data completeness from each CAN bus. When the bus with fewer packets is selected and packet loss is detected through sequence number gaps, the feedback mechanism triggers a switch to the other redundant channel to ensure complete data reception.
Solution Approach 2:
The system performs preliminary sequence number verification before accepting data from the selected channel. By checking sequence numbers in advance, the system can predict potential packet loss and switch to the other redundant channel proactively, preventing data completeness issues.
4Productivity
If packet counts from both CAN buses are equal, then data reception continues, but abnormal data causes the data to be actively discarded after cache is full
Solution Approach 1:
The patent implements sequence number comparison as a feedback mechanism to validate data from redundant channels with equal packet counts. When sequence numbers indicate abnormal data (mismatches or inconsistencies), the feedback triggers active discarding of unreliable data, preventing cache overflow with invalid information.
Solution Approach 2:
The patent converts the potential harm of equal packet counts from both channels (which could lead to cache overflow with abnormal data) into a benefit by using sequence number verification. The verification process identifies the trusted channel, transforming the equal-count scenario from a problem into an opportunity for validated data reception.
Data Source
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AI summary
This disclosure relates to the technical field of rail communication, and in particular to a CAN data receiving method and device for an Automatic Train Operation (ATO) system. Detecting CAN channel communication by comparing the number of packets of a CANO channel and the number of packets of a CAN1 channel and receiving data, when either the number of packets of the CANO channel or the number of packets of the CAN1 channel is greater than zero; identifying a CAN ID sequence number of the received data and comparing it with a sequence number expected to be received; and performing packet receiving according to a comparison result of the sequence numbers. This disclosure fully utilizes the redundancy of the two CAN communication channels. It respectively identifies the CAN ID sequence numbers of the same type of data on the redundant channels and compares them with the sequence number expected to be received. If correct, the data is accepted; if abnormal, it is either discarded or retained. By fully leveraging redundant transmission, it ensures that each received packet is verified against the data from both communication channels in terms of type and sequence number, thereby guaranteeing the accuracy and continuity of the data.