Absolute Angle Sensor Error Correction via Nonius Principle
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Solution Overview
Problem
Angle sensors face accuracy degradation due to manufacturing errors, non-linearities in magnetic field sensing elements, and sensitivity to temperature variations, which can sum and propagate through systems, affecting overall system accuracy and performance.
Innovation Solution
An absolute angle sensor system that includes two periodic angle sensors and an error correction processor to determine and correct errors using the Nonius principle, calculating the difference between product terms of periodic angle signals and feature numbers, and applying error constants to generate a corrected absolute angle signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple periodic angle sensors are used to determine absolute angle, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the absolute angle measurement function into two separate periodic angle sensors, each measuring the same physical quantity but with different error characteristics. This segmentation allows the system to capture multiple perspectives of the measurement, enabling error differentiation and correction through the Nonius principle while maintaining manageable individual sensor complexity.
Solution Approach 2:
The patent introduces an error correction processor as an intermediary component that receives signals from both periodic angle sensors, calculates the difference between their measurements using the Nonius principle, and generates a corrected absolute angle signal. This intermediary processing stage eliminates the need for complex hardware modifications to the sensors themselves, reducing overall device complexity while improving measurement precision.
2Measurement precision
If error correction processing is applied, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent performs error correction calculations in real-time as part of the signal processing pipeline, rather than requiring post-processing or external calibration procedures. The error correction processor continuously computes the difference between the two periodic angle measurements and applies correction, eliminating the need for separate preliminary calibration steps and reducing overall system complexity.
Solution Approach 2:
The system uses its own dual sensor measurements to self-correct errors through the Nonius principle. By comparing the measurements from two sensors with different error characteristics, the system automatically identifies and compensates for errors without requiring external reference standards or manual calibration, thereby reducing processing complexity while maintaining high precision.
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 improves the accuracy of absolute angular position determination by estimating and correcting errors, resulting in enhanced precision compared to existing sensors.
Implementation Method 1
a first periodic angle sensor configured to generate a first periodic angle signal indicative of an angle of a first magnetic field associated with a first track of a target; a second periodic angle sensor configured to generate a second periodic angle signal indicative of an angle of a second magnetic field associated with a second track of the target
Data Source
AI summary
In some embodiments, a method can include receiving, by an angle sensor, a first periodic angle signal indicative of an angle of a first magnetic field associated with a first track of a target; receiving, by the angle sensor, a second periodic angle signal indicative of an angle of a second magnetic field associated with a second track of the target; generating an uncorrected absolute angle signal indicative of an absolute angle of the target based on the first and second periodic angle signals; determining an estimated error associated with the uncorrected absolute angle signal based on the first periodic angle signal and the second periodic signal; subtracting the estimated error from the uncorrected absolute angle to generate a corrected absolute angle signal; and providing the corrected absolute angle signal as output of the angle sensor.