Vehicle Clock Synchronization via Ring Network Reference 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 need for centralized control and extensive clock-tree structures.
Innovation Solution
A control system utilizing a ring network with a primary controller sending a reference clock signal directly to node devices, enabling pulse-level synchronization and redundant signal paths for improved precision and reliability, 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, then centralized control and data frame exchange are implemented, but synchronization precision is low
Solution Approach 1:
The patent segments the centralized clock synchronization into distributed node devices, where each node independently performs timing based on received reference clock signals. This eliminates the complex centralized clock-tree structure and achieves pulse-level synchronization precision by distributing the synchronization function across multiple independent nodes rather than relying on a single primary controller.
Solution Approach 2:
The patent replaces the data-frame-based software synchronization mechanism (PTP/EtherCAT) with a direct hardware reference clock signal transmission. By substituting the mechanical/software approach of exchanging timing data frames with an electrical/hardware approach of directly transmitting reference clock signals, the system achieves higher synchronization precision equal to the pulse width of the reference clock signal.
2Reliability
If centralized control is used for clock synchronization, then a primary controller manages timing, but reliability is reduced due to single point of failure
Solution Approach 1:
The patent segments the centralized control function into multiple distributed node devices that can independently perform timing operations. Each node device receives reference clock signals and autonomously performs timing, eliminating the single point of failure in centralized control while maintaining synchronized operation across the network.
Solution Approach 2:
Each node device in the patent performs self-service timing operations by independently processing received reference clock signals and executing tasks based on local timing. This self-service capability at each node eliminates dependency on a central controller, improving reliability while simplifying the overall control structure.
3Measurement precision
If data frames are exchanged for synchronization, then clock error determination is performed, but synchronization precision is limited
Solution Approach 1:
The patent replaces the time-consuming data frame exchange and clock error calculation process with direct reference clock signal transmission. By substituting the software-based data processing approach with hardware-level signal transmission, the system achieves pulse-level synchronization precision and eliminates the time delays associated with data frame processing and error determination.
Solution Approach 2:
The patent skips the intermediate steps of data frame exchange, clock error determination, and calculation processing by directly transmitting reference clock signals to node devices. This rushing through the synchronization process at the hardware signal level rather than software data level achieves superior precision and reduces time loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances synchronization precision to the level of the reference clock signal's pulse width and ensures reliable signal transmission through redundant paths, improving system stability and flexibility.
Implementation Method 1
The at least one node device includes a phase-locked loop. The at least one node device is configured to: correct a frequency of a local clock signal of the node device based on the frequency of the reference clock signal by using the phase-locked loop, to maintain a target ratio between the frequency of the local clock signal of the node device and the frequency of the reference clock signal
Data Source
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AI summary
This application provides a control system, a clock synchronization method, a controller, a node device, and a vehicle, and relates to the field of electronic technologies in the automotive field. In the 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, so that the at least one node device can perform timing based on a frequency of the reference clock signal. In this way, precision of clock synchronization between the primary controller and the node device can be improved to precision equal to a pulse width of the reference clock signal. In addition, because the control system includes the ring network, it can be ensured that there are redundant paths during signal exchange between the primary controller and the node device, thereby ensuring reliability of signal transmission.