CAN Fault Isolation via Off-Board Controller Topology Analysis
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Solution Overview
Problem
Existing CAN systems are unable to effectively identify the root cause of faults, distinguish between transient and intermittent faults, and require separate monitoring hardware to detect communications faults, limiting their ability to isolate issues in vehicle controller area networks.
Innovation Solution
A method for monitoring CAN systems that detects inactive nodes and employs an off-board controller to identify candidate faults using network topology analysis, isolating faults by generating fault signature vectors to determine open links, wire shorts, or faulty controllers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate monitoring hardware is used to detect communications faults, then fault detection capability is improved, but device complexity increases
Solution Approach 1:
The existing controller nodes in the CAN network are made to perform dual functions: their primary control functions and additional fault monitoring functions. The controller receives messages from other nodes, analyzes communication status, detects inactive nodes, and identifies fault locations without requiring dedicated monitoring hardware. This multi-functional approach resolves the contradiction by improving fault detection capability while avoiding increased device complexity.
2Reliability
If fault detection is performed at message-receiving controller using signal supervision, then fault detection is achieved, but ability to identify root cause is lost
Solution Approach 1:
The system implements a feedback mechanism where the monitoring controller continuously receives communication messages from all CAN nodes, analyzes their activity status, and uses this feedback information to identify inactive nodes and determine fault locations. The feedback loop includes receiving messages, detecting inactive nodes, identifying candidate faults based on network topology, and isolating actual faults, thereby preserving root cause identification capability while maintaining fault detection.
3Reliability
If known detection systems are used, then loss of communications is detected, but transient and intermittent faults cannot be distinguished
Solution Approach 1:
The system performs preliminary monitoring and recording of node communication status continuously before faults occur. By maintaining ongoing surveillance of message transmission and reception patterns, the system captures transient and intermittent fault events as they happen, enabling precise discrimination between different fault types. The preliminary action of continuous monitoring ensures no fault event is missed, improving measurement precision for fault type discrimination.
Data Source
AI summary
A controller area network (CAN) on a mobile system has a plurality of CAN elements including a communication bus and nodes. A method for monitoring the CAN includes detecting inactive nodes of the CAN and employing an off-board controller to identify a candidate fault in the CAN based upon the inactive nodes of the CAN and a network topology for the CAN. A fault is isolated in the CAN based upon the candidate fault.