CAN Bus Fault Controller Isolation via Error Threshold Monitoring
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Solution Overview
Problem
In vehicle systems, faulty controllers can cause communication errors on the CAN bus, leading to corruption of messages and instability in vehicle operations, as existing technologies lack effective methods to isolate and reset fault-active controllers promptly.
Innovation Solution
A method is implemented to monitor bus communications, determine bus error counts, and isolate fault-active controllers by prohibiting them from communicating when error thresholds are exceeded, allowing successful controllers to be removed from the fault-active list, thereby preventing further message corruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a controller continues to communicate on the CAN bus despite exceeding error thresholds, then communication continuity is maintained, but message corruption and network instability increase
Solution Approach 1:
The patent extracts the faulty controller from the communication network by prohibiting it from transmitting messages on the CAN bus when error thresholds are exceeded. The monitoring controller identifies controllers with excessive bus errors and excludes them from the communication network, thereby removing the source of message corruption and stabilizing the network.
2Measurement precision
If all controllers are continuously monitored and evaluated, then fault detection accuracy is improved, but system complexity and processing overhead increase
Solution Approach 1:
The patent combines the monitoring function with the existing CAN bus communication infrastructure. The monitoring controller utilizes the same communication bus to both exchange messages and monitor error conditions, eliminating the need for separate monitoring hardware or channels. This integration maintains high fault detection accuracy while avoiding additional system complexity.
Solution Approach 2:
The monitoring controller automatically evaluates bus error counts and identifies faulty controllers without requiring external intervention or complex diagnostic systems. The system self-monitors communication quality and autonomously makes decisions about controller inclusion or exclusion based on predetermined error thresholds.
3Reliability
If faulty controllers are immediately isolated upon error detection, then network stability is maintained, but false positives may exclude healthy controllers
Solution Approach 1:
The patent establishes predetermined error thresholds before monitoring begins, creating clear criteria for when controllers should be excluded. These thresholds are set in advance to distinguish between normal communication variations and actual faults, preventing premature isolation of healthy controllers while ensuring timely exclusion of truly faulty ones.
Solution Approach 2:
The monitoring controller continuously evaluates bus error counts and provides feedback about controller performance. This ongoing feedback mechanism allows the system to adaptively adjust controller inclusion or exclusion based on real-time communication quality, maintaining network stability while avoiding false positives through continuous verification against error thresholds.
Data Source
AI summary
A method for monitoring communications among a plurality of controllers signally linked to a communication bus of a controller area network includes monitoring bus communications including determining bus error counts for a plurality of execution cycles. When a bus error count associated with message transmission from one of the controllers exceeds a predetermined threshold, the one of the controllers is prohibited from communicating on the communications bus for a predetermined period of time and is included in a subset of candidate fault-active controllers. Any of the plurality of controllers included within the subset of candidate fault-active controllers that successfully transmits a message is removed from the subset of candidate fault-active controllers. A fault-active controller is isolated based upon the subset of candidate fault-active controllers and the bus error counts.