Faulty Node Detection in CAN Bus Systems
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Solution Overview
Problem
Conventional error handling methods for CAN bus systems fail to timely detect and evaluate faulty nodes, leading to prolonged disruption of communication and increased weight and fuel consumption in vehicles due to the need for additional redundant nodes, as well as reduced system availability.
Innovation Solution
A method that involves a node incrementing an internal error counter and switching to an isolated state if the counter exceeds a threshold, with a state change counter tracking transitions from isolated to normal states, identifying nodes as faulty if the state change rate or number exceeds adjustable thresholds, allowing for early detection and notification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional error handling is used in CAN bus systems, then communication can continue with faulty nodes for extended periods, but faulty nodes cannot be detected timely and communication disruption is prolonged
Solution Approach 1:
The patent implements a feedback mechanism where the master node monitors the state changes of slave nodes and receives acknowledgments. When a slave node transitions from isolated to normal state, it sends an acknowledgment message to the master node, which updates its monitoring data. This feedback loop enables timely detection of faulty nodes while maintaining communication continuity through state monitoring and selective reconfiguration.
Solution Approach 2:
The system performs preliminary actions by pre-configuring backup communication paths and monitoring mechanisms. The master node continuously monitors slave node states and maintains updated monitoring data that includes alternative communication routes. When faults are detected, the system can immediately switch to pre-prepared backup paths, ensuring timely fault detection without communication disruption.
2Reliability
If additional redundant nodes are provided to ensure system availability, then system availability increases, but vehicle weight and fuel consumption increase
Solution Approach 1:
Instead of providing physical redundant nodes, the patent uses virtual redundancy through monitoring data and state information stored in the master node. The master node maintains copies of slave node monitoring data, error counters, and state information, enabling it to detect faults and reconfigure communication paths software-based rather than requiring additional hardware nodes. This reduces vehicle weight while maintaining system availability.
Solution Approach 2:
The master node performs multiple functions including communication coordination, fault detection, state monitoring, and reconfiguration management. By consolidating these functions in a single node with comprehensive monitoring capabilities, the system eliminates the need for separate redundant nodes. The master node universally handles all fault detection and communication management tasks, reducing overall system weight while ensuring availability.
3Productivity
If faulty nodes are not detected timely, then communication can continue, but maintenance complexity increases and system availability decreases
Solution Approach 1:
The patent replaces manual fault detection and maintenance procedures with automated electronic monitoring and state tracking. The master node automatically monitors slave node states, increments error counters, detects faults through state change analysis, and triggers reconfiguration without manual intervention. This automation simplifies maintenance by providing automated fault identification and reduces communication disruption, maintaining throughput while easing repair processes.
Solution Approach 2:
The system performs self-diagnosis and self-reconfiguration through automated monitoring and fault detection mechanisms. The master node continuously monitors slave node states and automatically detects when nodes transition between isolated and normal states. Upon detecting faults, the system autonomously reconfigures communication paths and updates monitoring data without requiring external intervention, thereby maintaining productivity and simplifying maintenance.
Data Source
AI summary
The invention relates to a method for detecting a faulty node (2), which is connected to a bus (3), wherein in a normal operating mode the node (2) incrementally increases an internal fault counter (FZ) upon detection of a fault, and wherein the node (2) switches into an isolated operating mode in which the node (2) does not exchange messages via the bus (3) if the internal fault counter (FZ) of the node (2) has exceeded a predetermined fault threshold. According to the invention, the node (2) switches from the isolated operating mode into the normal operating mode when a condition is met and this mode change is detected, and the node (2) is recognized as being faulty if a rate of the detected mode changes has exceeded a settable switch rate or a number of the detected mode changes has exceeded a settable mode change threshold.