CAN Inhibit Path Diagnostic System for Fault Isolation
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Solution Overview
Problem
Current vehicle control systems face challenges in effectively diagnosing and isolating faults in control modules and message transmission paths, which can lead to operational inefficiencies and potential system failures.
Innovation Solution
The implementation of an inhibit path diagnostic system that includes control modules capable of transmitting messages over a CAN network, disabling message transmission paths when necessary, and detecting faults through feedback signals to perform remedial tasks, ensuring proper operation of hardware and software associated with disabling control modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second control module disables the message transmission path to isolate faults, then system reliability is improved, but the complexity of the control system increases due to additional inhibit path circuits and diagnostic capabilities
Solution Approach 1:
The control system is divided into distinct functional modules: primary control modules for actuator control, secondary control modules for monitoring, and inhibit path circuits for isolation. This segmentation allows fault containment to specific modules without affecting the entire system, resolving the contradiction by making the system more manageable and reliable despite increased complexity.
Solution Approach 2:
The inhibit path circuit acts as an intermediary component between the secondary control module and the primary control module. It receives disable control signals from the secondary module and physically disconnects the message transmission path, providing a controlled isolation mechanism that improves reliability while maintaining system architecture.
2Reliability
If diagnostic tests are continuously performed to detect faults early, then system reliability is improved, but the loss of time for normal operation increases due to frequent testing interruptions
Solution Approach 1:
The secondary control module performs diagnostic tests periodically by transmitting request signals at intervals and comparing responses. This periodic testing approach allows the system to maintain reliability through regular health checks while minimizing interruptions to normal operation, as tests are conducted at scheduled times rather than continuously.
Solution Approach 2:
The diagnostic system uses feedback mechanisms where the secondary control module receives response signals from primary modules, compares them against expected values, and detects faults based on discrepancies. This feedback loop enables efficient fault detection without requiring continuous intervention, optimizing the balance between reliability and operational time.
3Reliability
If the system disables control modules upon fault detection to prevent system failures, then safety is improved, but the productivity of the vehicle control system decreases due to reduced operational capacity
Solution Approach 1:
When a fault is detected in a primary control module, the inhibit path circuit extracts or removes that module from the active system by disabling its message transmission path. This isolation prevents the faulty module from causing system-wide failures while allowing the remainder of the control system to continue operating, thus maintaining productivity despite the loss of one module.
Solution Approach 2:
The system prepares for potential failures by having inhibit path circuits ready to isolate faulty modules before they can cause cascading system failures. This preemptive isolation mechanism cushions the system against complete failure, allowing degraded operation to continue rather than forcing a total system shutdown.
Data Source
AI summary
An inhibit path diagnostic system includes a first control module. The first control module includes a message output and transmits a first message from the message output to a controller area network (CAN) via a message transmission path. An inhibit path circuit includes the message transmission path. A second control module transmits a disable control signal to the inhibit path circuit to disable the message transmission path. The first control module transmits a second message from the message output subsequent to and based on the transmitting of the disable control signal. At least one of the first control module and the second control module detects a fault of the inhibit path circuit subsequent to the transmitting of the second message and based on a feedback signal from the CAN.