Vehicle Control Unit Clock Synchronization via Feedback Loop
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Solution Overview
Problem
In electronic systems for motor vehicles with multiple control units, asynchronous clocking of processors due to independent clock generators leads to instabilities, inaccuracies, and inefficiencies in motor torque delivery, resulting in suboptimal steering feel and positioning accuracy.
Innovation Solution
An electronic system with a control loop that determines the time difference between control units and adjusts the clock generators to reduce or eliminate asynchronicity, using a master control unit and time stamps to synchronize the processors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each control unit has its own independent clock generator, then the system achieves greater independence and reliability of individual control units, but the clock generators run asynchronously leading to timing errors and reduced system accuracy
Solution Approach 1:
The patent implements a feedback mechanism where the master control unit measures time differences between its clock and slave control unit clocks, then sends correction values back to the slave units. This closed-loop feedback continuously adjusts slave clock timing to synchronize with the master clock, resolving the asynchronicity problem while maintaining independent clock generators.
Solution Approach 2:
The master control unit acts as an intermediary between the independent clock generators. It receives timing information from slave units, processes the time difference data, and distributes synchronization corrections to maintain coordinated operation across all control units without requiring them to share a single clock source.
2Device complexity
If processors are clocked asynchronously, then each processor operates independently without complex synchronization hardware, but calculation results are not available simultaneously causing delays in control loops
Solution Approach 1:
The system uses feedback timing measurements where the master control unit determines time differences between received signals and its own clock cycles. This feedback information is used to calculate correction values that are sent back to slave control units, enabling them to adjust their timing and provide results in a synchronized manner without complex hardware synchronization.
Solution Approach 2:
The patent changes the timing parameters of slave control units by applying correction values to their clock generators. This adjusts the operating frequency or phase of slave clocks to match the master clock, ensuring that calculation results become available simultaneously across all control units while maintaining software-based synchronization.
3Adaptability or versatility
If clock generators run at slightly different frequencies, then each control unit maintains its own timing autonomy, but time differences accumulate leading to instability in motor torque delivery
Solution Approach 1:
The master control unit continuously measures time differences between its clock and slave control unit clocks over multiple cycles. This continuous feedback allows the system to detect and correct frequency drift between clock generators, maintaining synchronized operation and stable motor torque delivery while preserving the autonomy of individual control unit clock generators.
Solution Approach 2:
The master control unit serves as an intermediary that coordinates the timing of all control units. It receives timing data from slave units, calculates the appropriate correction values based on accumulated time differences, and distributes these corrections to maintain synchronized operation, thereby ensuring stable motor torque delivery across all actuators.
Data Source
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AI summary
The invention relates to an electronic system of a motor vehicle with at least two mutually communicating control units (30, 34), each configured to send and receive signal information and each having its own clock generator (48), wherein each control unit (30, 34) is configured to create a timestamp with the time of generation of a signal (44) in addition to signal information, and wherein at least one control element (52) is provided which is designed such that a time difference between two timestamps relating to the same signal information is taken into account as a parameter of a control loop to reduce the asynchronicity of the clock generators (48) in order to reduce or eliminate asynchronicity of the clock generators (48).