CAN Bus Traffic Supervision via Dual-Chip Frame Comparison
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Solution Overview
Problem
Controller Area Network (CAN) systems face reliability issues due to the lack of safety integrity levels (SIL) in some CAN chips, potential chip failures, and the absence of health checks for these chips, leading to corrupted data payloads.
Innovation Solution
The implementation of a system that uses at least two CAN chips and a CAN frames comparison portion to detect failures by comparing identical CAN frames received from each chip within a specified comparison period, thereby ensuring data integrity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only a single CAN chip is used for communication, then the device complexity is low, but the reliability of CAN data payload is compromised due to potential chip failures and lack of health checks
Solution Approach 1:
The system divides the communication function into multiple independent CAN chips (at least two) that operate in parallel. Each CAN chip independently receives and processes CAN frames from the bus, enabling functional segmentation that improves reliability through redundancy while maintaining manageable complexity through modular architecture
Solution Approach 2:
The system implements beforehand cushioning by continuously monitoring the health status of CAN chips and comparing their outputs. Health check functions and frame comparison mechanisms are prepared in advance to detect and compensate for potential chip failures before they compromise data integrity, cushioning against reliability issues
2Reliability
If health check functions are continuously monitored, then the reliability of CAN data payload is improved, but the loss of time for processing increases
Solution Approach 1:
The health monitoring and frame comparison operations are performed continuously in parallel with normal CAN communication processing. The comparison function operates continuously on incoming frames from multiple CAN chips without interrupting the useful action of data transmission, eliminating time loss by making monitoring a continuous background process
Solution Approach 2:
Health checks and frame comparisons are performed preliminarily on incoming CAN frames before they are processed further in the system. By validating frame integrity and chip health status in advance, the system prevents processing of corrupted data without adding significant time overhead to the overall communication workflow
3Reliability
If multiple CAN chips are used with frame comparison, then the reliability of CAN data payload is enhanced, but the device complexity increases
Solution Approach 1:
The CAN chips and associated processing units are designed with multi-functionality, serving both as communication interfaces and as health monitoring nodes. Each CAN chip performs dual functions of data transmission and self-diagnosis, reducing overall device complexity by eliminating dedicated monitoring hardware and leveraging the universal capability of communication components
Solution Approach 2:
The system merges the functions of multiple CAN chips into a unified communication interface by combining their outputs through a comparison logic unit. This merging approach consolidates redundant functionality into a single reliable data stream, reducing device complexity by integrating multiple components into a cohesive system rather than managing them as separate independent units
Data Source
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AI summary
A method of common controller area network (CAN) bus traffic supervision on a system having a common CAN bus, a first CAN chip and a second CAN chip, the first CAN chip and the second CAN chip are coupled together with the common CAN bus, the method includes comparing a first CAN frame received from the first CAN chip to a second CAN frame received from the second CAN chip within a CAN comparison period, and detecting a failure of at least the first CAN chip or the second CAN chip. Detecting the failure of at least the first CAN chip or the second CAN chip includes determining that the first CAN frame is not identical to the second CAN frame within the CAN comparison period.