Rotation Angle Detection Device With Dual Filter Characteristics
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Solution Overview
Problem
Existing rotation angle detection devices face challenges in accurately acquiring error information for correcting rotation angle measurements, leading to inaccuracies in detecting the rotation angle of a magnetic field generation source.
Innovation Solution
A rotation angle detection device and method that utilize a magnetic field detection device to detect magnetic fields in multiple directions, employing a correction value calculation unit and filter units with different filter characteristics to improve accuracy, allowing for precise calculation and output of the rotation angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single filter characteristic is used for both angle output and correction value calculation, then the device complexity is reduced, but the measurement precision of the rotation angle deteriorates
Solution Approach 1:
The filter unit is segmented to provide at least two different filter characteristics: a first filter characteristic for angle output signal processing and a second filter characteristic for correction value calculation. This segmentation allows each filter to be optimized for its specific purpose, improving overall measurement precision without requiring a single complex filter to handle all functions
Solution Approach 2:
The filter unit is designed to dynamically switch between different filter characteristics based on the operational mode. When correction values are being calculated, the second filter characteristic is applied; when angle output signals are being generated, the first filter characteristic is applied. This dynamic adaptation allows the system to maintain high precision while managing complexity through context-dependent filter selection
2Object-affected harmful factors
If a narrow band filter is used for angle output, then noise is reduced, but the correction value calculation accuracy deteriorates
Solution Approach 1:
Different filter characteristics are applied to different signal processing paths based on their specific requirements. The first filter characteristic (narrower band) is applied locally to the angle output path where noise reduction is critical, while the second filter characteristic (wider band) is applied locally to the correction value calculation path where signal fidelity is more important. This local optimization resolves the contradiction by allowing each path to have the appropriate filter characteristics for its function
3Measurement precision
If a wide band filter is used for correction value calculation, then calculation accuracy is improved, but noise in the angle output increases
Solution Approach 1:
The filtering function is segmented into two distinct filter paths: one dedicated to correction value calculation with wide band characteristics for high accuracy, and another dedicated to angle output with narrow band characteristics for noise reduction. This segmentation allows the system to simultaneously achieve both goals without compromise
Solution Approach 2:
The correction values calculated using the wide band filter are fed back into the angle output signal generation process. This feedback mechanism allows the high-accuracy correction values to improve the overall angle measurement while the narrow band filter in the output path suppresses noise, resolving the contradiction between correction accuracy and output noise
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 enhances the accuracy of rotation angle detection by effectively calculating correction values and filtering signals, resulting in improved signal-to-noise ratio and reduced noise in the detected angle, thereby correcting errors and stabilizing the detection process.
Implementation Method 1
detect a rotation angle of a magnetic field generation source, based on magnetic field components measured around the rotating body
Data Source
AI summary
Provided is a rotation angle detection device configured to detect a rotation angle of a magnetic field generation source, based on a magnetic field in at least two directions detected by a magnetic field detection device. The rotation angle detection device includes a correction value calculation unit configured to calculate a correction value of the rotation angle; an angle output unit configured to output an angle output signal indicative of the rotation angle of the magnetic field generation source, based on a magnetic field detection signal to be output from the magnetic field detection device and the correction value; and a filter unit capable of selecting a first filter characteristic, which is to be used for outputting the angle output signal, and a second filter characteristic, which is to be used for calculating the correction value and is different from the first filter characteristic.