Supervisory Node Synchronization for FlexRay Networks
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Solution Overview
Problem
In distributed control networks using the FlexRay protocol, nodes experience synchronization issues due to subtle errors in clock frequencies, leading to deviations in communication cycles and potential loss of synchronization.
Innovation Solution
A node system where each node includes a clock generator and a communication controller that adjusts a rate correction value to synchronize cycles, with a supervisory node managing cycle microtick counts and rate correction limits to maintain synchronization across nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If each node uses its own clock generator to manage communication cycles, then the system achieves distributed control and autonomy, but clock frequency errors cause synchronization deviations and communication cycle misalignment
Solution Approach 1:
The patent implements a feedback mechanism where nodes transmit synchronization information (such as timestamped frames or dedicated sync packets) to allow other nodes to measure time differences and adjust their local clocks. This continuous feedback loop compensates for clock frequency errors and maintains synchronization across the distributed network, resolving the contradiction between autonomous distributed control and synchronization accuracy.
Solution Approach 2:
The patent adjusts the timing parameters of communication cycles dynamically based on measured synchronization status. Nodes modify cycle lengths, transmission timing offsets, and synchronization intervals to compensate for clock frequency deviations, thereby maintaining reliable communication despite inherent clock errors in each node.
2Reliability
If nodes continuously adjust rate correction values to synchronize cycles, then synchronization reliability improves, but the complexity of the control system increases
Solution Approach 1:
The patent implements self-service mechanisms where nodes automatically perform synchronization adjustments without external intervention. Each node autonomously measures time differences, calculates required corrections, and applies rate corrections to its own clock, eliminating the need for complex centralized control while maintaining synchronization reliability across the distributed system.
Solution Approach 2:
The patent employs dynamic adjustment mechanisms where synchronization parameters such as rate correction values are continuously updated based on real-time measurement of time differences between nodes. This dynamic approach allows the system to adapt to changing synchronization conditions without requiring predetermined complex control algorithms, reducing overall system complexity while maintaining reliability.
3Reliability
If nodes stop frame transmission when rate correction exceeds limits, then synchronization failures are prevented, but communication continuity is reduced
Solution Approach 1:
The patent implements beforehand cushioning by establishing rate correction limits and monitoring mechanisms that prevent excessive corrections before they cause synchronization failures. The system proactively identifies when corrections approach dangerous thresholds and takes preventive actions, such as adjusting synchronization frequency or alerting operators, to avoid communication discontinuities and maintain continuous operation.
Data Source
AI summary
A node system includes a first node, a second node, and a supervisory node which transmit frames while increasing or decreasing the cycle microtick count, and determines reduced cycle microtick counts by subtracting or adding a rate correction limit value from or to the cycle microtick count of the supervisory node when reception of the first frame transmitted by the first node stop and the cycle microtick count of the supervisory node when reception of the first and second frames stop.