3D Magnetic Position Sensing for Absolute Cycle Detection
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Solution Overview
Problem
Conventional magnetic position sensing technologies in automotive and brushless DC motor control systems rely on only two vector components of a magnetic field, which are inadequate for providing high-accuracy and high-precision measurements required for modern, time-sensitive control systems.
Innovation Solution
A system and method that utilize a magnetic field with three orthogonal vector components, allowing a sensor to measure their magnitudes and a controller to determine the relative and absolute position of an object by analyzing these components, enabling precise position sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods use only two vector components of a magnetic field for position sensing, then the device complexity is reduced, but the measurement precision is insufficient for high-accuracy control systems
Solution Approach 1:
The patent transitions from measuring only two vector components (2D) of the magnetic field to measuring three vector components (3D) including the radial component. This dimensional expansion provides additional information about the magnetic field vector, enabling high-accuracy determination of absolute position by resolving the ambiguity of cycle identification while maintaining a straightforward sensor configuration.
2Measurement precision
If three vector components of a magnetic field are measured, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent segments the position determination process into two distinct stages: first determining relative position within a cycle using two vector components (sine and cosine), then determining the absolute cycle number using the third radial vector component. This segmentation allows the system to achieve high-accuracy absolute position sensing by breaking down the complex measurement task into manageable parts, each handled by specific sensor components and processing steps.
3Reliability
If only two vector components are used, then the ease of operation is maintained, but the reliability of position determination is insufficient for time-sensitive control systems
Solution Approach 1:
The patent employs feedback mechanisms where the controller iteratively processes the three measured vector components to determine both the relative position within a cycle and the absolute cycle number. The system uses the measured radial component to identify the correct cycle, then combines this with the two-component position calculation to provide reliable absolute position feedback. This feedback-based approach ensures high reliability for time-sensitive control applications while maintaining operational simplicity through automated processing.
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
This approach provides high-accuracy and high-precision position determination, suitable for innovative control systems like automated manual transmissions and high-efficiency brushless DC motor control systems.
Implementation Method 1
measuring three vector components of a magnetic field produced by the object
Data Source
AI summary
Systems and methods for determining position are provided. An object produces a magnetic field having a first vector component, a second vector component, and a third vector component that are orthogonal to one another. A sensor measures a magnitude of each of the first, second, and third vector components when the object is within a range of positions. A controller is connected to the sensor and determines a relative position of the object within an undetermined cycle of a plurality of cycles based on the magnitude of the first vector component and the magnitude of the second vector component. The controller determines a cycle of the plurality of cycles in which the object is located based on the magnitude of the third vector component. The controller determines an absolute position of the object based on the relative position of the object and the cycle in which the object is located.