CAN Bus Short Fault Isolation via Monitoring Controller
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Solution Overview
Problem
Existing CAN systems are unable to accurately identify the root cause of faults and distinguish between transient and intermittent faults, limiting their effectiveness in isolating issues within the network.
Innovation Solution
A monitoring controller is implemented in the CAN network that measures CAN-H and CAN-L wire voltages, utilizing a split termination configuration and a fault signature matrix to isolate short faults by analyzing voltage waveforms and resistance, enabling precise fault detection and isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional fault detection methods are used, then fault detection capability is provided, but fault isolation precision and root cause identification are insufficient
Solution Approach 1:
The patent segments the CAN bus into multiple test segments by introducing a monitoring controller that can isolate specific portions of the bus for testing. This allows the system to divide the fault detection task into smaller, manageable segments, enabling precise identification of where a short fault occurs along the bus while maintaining overall system functionality.
Solution Approach 2:
The monitoring controller acts as an intermediary device between the existing CAN controllers and the fault detection system. It introduces additional measurement capabilities (voltage sensing across multiple points) without disrupting normal CAN communication, serving as a mediator that provides enhanced diagnostic information while maintaining system operation.
2Device complexity
If simple signal supervision is used, then implementation complexity is low, but ability to distinguish transient and intermittent faults is insufficient
Solution Approach 1:
The system performs preliminary measurements of voltage at multiple points along the CAN bus continuously, even before a fault occurs. By pre-establishing baseline voltage profiles and storing historical data, the system can later distinguish between transient disturbances and actual faults, as well as differentiate between intermittent and persistent conditions, without adding significant complexity to the detection architecture.
Solution Approach 2:
The patent adds a temporal dimension to fault detection by measuring voltage at multiple time points and comparing changes over time. This dimensional expansion from single-point-in-time detection to multi-time-point analysis enables the system to distinguish between transient faults (which resolve quickly) and intermittent or permanent faults, enhancing reliability without proportionally increasing complexity.
3Measurement precision
If comprehensive fault isolation is implemented, then fault identification accuracy is improved, but measurement and detection difficulty increases
Solution Approach 1:
The monitoring controller is designed as a multi-functional device that performs both normal CAN communication tasks and comprehensive fault detection functions. By integrating voltage measurement at multiple bus points, fault isolation logic, and communication monitoring into a single controller, the system achieves high fault isolation accuracy without proportionally increasing overall system complexity, as the same hardware performs multiple functions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for effective identification and isolation of faults, improving the reliability of the CAN network by distinguishing between different types of faults and reducing the impact of transient and intermittent issues.
Implementation Method 1
measuring a CAN-H wire voltage, measuring a CAN-L wire voltage, and isolating a short fault based upon the CAN-H wire voltage and the CAN-L wire voltage
Data Source
AI summary
A controller area network (CAN) includes a CAN bus having a CAN-H wire, a CAN-L wire, and a pair of CAN bus terminators located at opposite ends of the CAN bus. The CAN further includes a plurality of nodes including controllers wherein at least one of the controllers is a monitoring controller. The monitoring controller includes a detection control routine for isolating faults on the CAN bus including measuring a CAN-H wire voltage, measuring a CAN-L wire voltage, and isolating a short fault based upon the CAN-H wire voltage and the CAN-L wire voltage.