Magnetic Angular Position Sensing With External Lookup Tables
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Solution Overview
Problem
Magnetic position sensors used in safety-critical applications, such as aerospace, are time-consuming and expensive to certify due to complex calculations performed by integrated circuits.
Innovation Solution
A magnetic position sensor that determines angular position using a look-up table populated with data for orthogonal vector components of the magnetic field, eliminating the need for complex integrated circuits and calculations, and includes a 1D or 2D look-up table stored in external memory to determine angular positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex integrated circuits with microprocessors are used to calculate angular position, then measurement precision is improved, but device complexity and certification cost increase
Solution Approach 1:
The patent extracts the complex calculation functions from the integrated circuit and relocates them to an external lookup table stored in non-volatile memory. The integrated circuit itself is simplified to only perform data retrieval and basic signal processing, while the angular position calculation algorithms are stored externally and executed by fetching pre-computed values from the lookup table based on sensor inputs.
Solution Approach 2:
The patent performs preliminary calculations of angular position values during the manufacturing and calibration phase, storing pre-computed lookup values in non-volatile memory. During operation, the system simply retrieves these pre-calculated values based on current sensor readings, eliminating the need for real-time complex calculations and significantly reducing operational complexity.
2Measurement precision
If complex calculations are performed by integrated circuits, then angular position can be determined, but certification time increases
Solution Approach 1:
By extracting complex calculation algorithms from the integrated circuit and placing them in external non-volatile memory, the patent simplifies the certified system to only include basic sensor reading and lookup table retrieval functions. This reduction in computational complexity within the certified component significantly decreases certification time while maintaining angular position determination accuracy.
Solution Approach 2:
The patent uses a lookup table that contains pre-computed angular position values copied from complex calculations performed during manufacturing. Instead of performing these calculations during operation, the system copies and retrieves pre-validated values from memory, reducing the certification burden to verifying the lookup table integrity rather than validating complex real-time calculation algorithms.
3Device complexity
If lookup table is used to determine angular position, then device complexity is reduced, but memory requirements increase
Solution Approach 1:
The patent optimizes the lookup table data structure by storing angular position values in compressed or optimized formats, and by implementing selective storage of only critical lookup points. The system changes the parameter representation to use efficient data types and storage schemes that reduce memory requirements while maintaining the necessary precision for angular position determination.
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
The solution provides a reliable and cost-effective method for determining angular positions without complex calculations, suitable for safety-critical applications by minimizing errors and reducing certification time.
Implementation Method 1
The at least one magnetic sensor determines different vector components of a magnetic field of the magnet
Data Source
Figure 1A~1B
Figure 2~4
Figure 3~5
AI summary
A magnetic position sensor for determining the angular position of a magnet on a rotatable component, comprising: at least one magnetic sensor (30) for determining different vector components of a magnetic field of the magnet; a memory having a look-up table (34) stored therein that is populated with data representative of different angular positions of the magnet, the data representative of each angular position being correlated with data in the look-up table (34) that is representative of the vector components that would be detected by the at least one magnetic sensor at that angular position; wherein the magnetic position sensor is configured to use the vector components determined by the magnetic sensor and logic to determine the angular position of the magnet from the look-up table (34).