Vehicle Control Clock Synchronization via Ring Network Signals
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Solution Overview
Problem
Existing clock synchronization methods in vehicle control systems, such as Precision Time Protocol (PTP) and Ethernet Control Automation Technology (EtherCAT), suffer from low synchronization precision and reliability due to the reliance on data frame exchanges between ECUs.
Innovation Solution
A control system utilizing a ring network with a primary controller that directly sends a reference clock signal to node devices, enabling precise clock synchronization and redundant signal exchange paths, and incorporating phase-locked loops for frequency correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PTP or EtherCAT is used for clock synchronization via data frame exchanges, then clock synchronization can be implemented among multiple ECUs, but synchronization precision is low
Solution Approach 1:
The patent extracts the clock synchronization function from the data frame exchange protocol and implements it through a dedicated reference clock signal transmission path. The primary controller separately transmits the reference clock signal through the ring network, independent of the PTP or EtherCAT data frames, thereby achieving pulse-level synchronization precision while simplifying the synchronization mechanism.
Solution Approach 2:
The patent introduces a dedicated reference clock signal as an intermediary carrier for time synchronization information. Instead of embedding synchronization data within complex data frames, the system uses a separate clock signal pathway that directly conveys timing information from the primary controller to secondary controllers, achieving higher precision.
2Reliability
If a ring network structure is used for signal transmission, then redundant signal exchange paths are ensured improving reliability, but device complexity increases
Solution Approach 1:
The patent implements a dynamic ring network where the reference clock signal can be transmitted in either clockwise or counter-clockwise direction depending on system requirements. The ring structure allows flexible signal routing with automatic failover capabilities, maintaining reliability while adapting to different operational scenarios.
3Measurement precision
If the primary controller directly sends the reference clock signal to node devices, then clock synchronization precision is improved to pulse level, but the frequency may be too high for node devices to support
Solution Approach 1:
The patent employs frequency division to transform the high-frequency reference clock signal into a lower-frequency signal that node devices can process. The primary controller divides the reference clock signal frequency before transmission through the ring network, ensuring compatibility with node device capabilities while preserving synchronization precision through the dedicated clock pathway.
Data Source
AI summary
The present application relates to control systems, clock synchronization methods, controllers, node devices, and vehicles. In one example control system provided in this application, a primary controller directly sends a reference clock signal to at least one node device by using a ring network, and the at least one node device performs timing based on a frequency of the reference clock signal. The reference clock signal is obtained by performing frequency division on a local clock signal of the primary controller.