Electric Power Steering Timestamp Synchronization
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Solution Overview
Problem
Conventional electric power steering systems face challenges in accurately synchronizing multiple sensors for precise steering angle detection, leading to increased angle errors at higher steering speeds due to independent sensor operations and digital communication errors.
Innovation Solution
The system incorporates a time stamping mechanism to synchronize detection signals from multiple sensors, using a vernier calculation to minimize angle errors by searching for synchronized signals and performing binary searches when steering speed exceeds a threshold, thereby reducing time and angle errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors operate independently to detect steering angle, then detection coverage is improved, but angle error increases proportionally to steering speed
Solution Approach 1:
The patent combines multiple independent sensor detections by merging their data through a unified time reference system. Each sensor's detection value is tagged with a timestamp, and the control unit synchronizes these values to a common time base, effectively merging the sensor outputs while maintaining their individual detection capabilities.
Solution Approach 2:
The patent introduces a timestamp as an intermediary element that mediates between multiple independent sensors and the control unit. The timestamp serves as a common reference that allows the control unit to synchronize and correlate detection values from different sensors without direct physical connection between sensors.
2Device complexity
If digital communication is used for sensor data transmission, then system integration is improved, but time error and angle error increase
Solution Approach 1:
The patent applies preliminary action by attaching timestamps to sensor detection values at the source before transmission. This pre-synchronization approach ensures that time reference information is embedded in the data itself, allowing the control unit to compensate for transmission delays without requiring complex real-time synchronization protocols.
3Speed
If steering speed increases to improve responsiveness, then steering performance is improved, but angle detection error increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the synchronization status of sensor data and using this information to adjust the detection and control process. The control unit calculates angle errors based on synchronized sensor data and uses this feedback to maintain accurate steering angle detection even at high steering speeds.
Data Source
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AI summary
[Problem] An object of the present invention is to provide an electric power steering apparatus that is capable of taking an accurate synchronization and suppressing an angle error by attaching a time stamp every time a detection signal from each sensor is received, and raises a steering speed that a steering angle detection is established. [Means for solving the problem] An electric power steering apparatus having a function for detecting a steering speed, comprises a time stamp attaching section that attaches a time stamp ATi to a detection signal Ai and attaches a time stamp BTj to a detection signal Bj; a storing section that stores the detection signal Bj to which the time stamp BTj is attached; a synchronous signal searching section that searches the detection signal Bj most synchronized with the detection signal Ai based on the time stamps ATi and BTj; a vernier calculating section that performs a calculation of an angle difference between synchronous signals searched by the synchronous signal searching section and a vernier calculation and outputs an absolute steering angle of a sensor reference; an initial steering angle calculating section that calculates an initial steering angle value from the absolute steering angle; and a steering angle output section that obtains a steering angle.