Dynamic Recovery Timer for Vehicle Controller Network Stability
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Solution Overview
Problem
Conventional vehicle controller networks rely on predetermined timers for controller malfunction recovery, which can be insufficient due to transmission delays on the CAN, leading to incorrect designation of recovered controllers as malfunctioning and in need of service.
Innovation Solution
Implementing a dynamic recovery timer set based on vehicle-wide synchronized time-stamps to determine worst-case transmission delays, preventing incorrect designation of recovered controllers by adjusting the recovery time dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predetermined timer is used for controller malfunction recovery, then the system structure is simple, but transmission delays cause incorrect designation of recovered controllers as malfunctioning
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static predetermined timer to a dynamic recovery timer that adapts to actual transmission conditions. The recovery timer is calculated based on real-time transmission delay measurements between controllers, allowing the system to adjust the recovery time window dynamically. This ensures that recovered controllers are not incorrectly designated as malfunctioning while maintaining system reliability.
Solution Approach 2:
The patent implements feedback by having controllers monitor and measure actual transmission delays through time-stamping mechanisms. Each controller timestamps messages sent and received, calculates the actual transmission delay, and uses this feedback information to adjust the recovery timer duration. This closed-loop feedback mechanism ensures the recovery timer accurately reflects current system conditions rather than relying on fixed predetermined values.
2Reliability
If a predetermined timer is used for controller malfunction recovery, then the implementation is simple, but transmission delays result in unnecessary service interventions
Solution Approach 1:
The patent applies preliminary action by having controllers continuously exchange timestamped messages and pre-calculate transmission delay characteristics before malfunction events occur. Each controller maintains records of transmission times and establishes baseline delay values during normal operation. When a malfunction occurs, the system uses these pre-established delay characteristics to quickly determine an appropriate recovery timer without requiring extensive real-time measurements, thus reducing the time loss while improving accuracy.
3Measurement precision
If time-stamping with synchronized clocks is implemented to determine worst-case transmission delay, then controller recovery accuracy improves, but the system complexity increases
Solution Approach 1:
The patent applies universality by designing the time-stamping mechanism to serve multiple functions simultaneously. The same timestamping infrastructure is used for both measuring transmission delays and providing chronological ordering of events across different controllers. The synchronized clock system serves dual purposes: establishing precise time references for delay calculation and creating a universal time reference frame for coordinating recovery actions across the controller network, thereby reducing overall system complexity.
Data Source
AI summary
A vehicle includes a controller area network (CAN) and a plurality of a controllers in communication with each other via the CAN, wherein each controller of the plurality of controllers is configured to time-stamp messages transmitted via the CAN using a vehicle-wide synchronized clock, determine a worst-case transmission delay via the CAN based on the time-stamps for messages received from other controllers of the plurality of controllers, and based on the worse-case transmission delay, set a dynamic recovery timer for a malfunctioning controller of the plurality of controllers to recover after its malfunction, wherein the dynamic recovery timer prevents a particular controller that was malfunctioning but has since recovered from being incorrectly designated as a malfunctioning controller in need of service.