Angular Error Compensation Using Harmonic Analysis
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Solution Overview
Problem
Conventional methods for compensating angular errors in magnetic devices are inadequate, particularly due to positioning inaccuracies, non-ideal magnetic properties, and temperature fluctuations, which result in offset, gain, and orthogonality errors.
Innovation Solution
A method that uses a permanent magnet and at least two magnetic field sensors to generate sine and cosine signals, which are then processed using an arc tangent function to form an evaluation signal. Correction values for gain and orthogonality errors are determined by analyzing second and third harmonics in the signals, allowing for minimization of angular deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional compensation methods are used, then offset, gain, and orthogonality errors can be corrected to some extent, but positioning inaccuracies and misalignment errors cannot be compensated
Solution Approach 1:
The patent implements a feedback mechanism where the evaluation signal is continuously monitored for angular deviations, and correction values are dynamically adjusted based on the detected errors. The measurement and evaluation unit receives feedback about positioning inaccuracies and misalignment, then modifies the correction values for gain and orthogonality errors to compensate for these systematic deviations, thereby improving both measurement precision and compensation effectiveness.
Solution Approach 2:
The patent changes the parameters of the correction values dynamically based on the detected angular deviations. By adjusting the correction values for gain errors and orthogonality errors in response to measured positioning inaccuracies and misalignment, the system adapts its compensation strategy to address the specific error characteristics, enabling compensation for previously uncorrectable error types while maintaining high measurement precision.
2Measurement precision
If more magnetic field sensors are used, then magnetic interference fields can be compensated and angular position can be calculated more accurately, but device complexity increases
Solution Approach 1:
The patent makes the measurement and evaluation unit multi-functional by enabling it to perform both the basic angular position calculation from sensor signals and the advanced compensation for positioning inaccuracies and misalignment. This universal approach allows the same unit to handle multiple error types without requiring separate dedicated systems, thereby improving angular position accuracy while limiting the increase in device complexity.
Solution Approach 2:
The system performs self-compensation by using its own measurement capabilities to detect and correct errors. The measurement and evaluation unit analyzes the signals from the magnetic field sensors to identify angular deviations caused by positioning inaccuracies and misalignment, then automatically adjusts correction values without requiring external intervention or additional specialized sensors, thus improving accuracy with minimal complexity increase.
3Measurement precision
If correction values for gain and orthogonality errors are determined through complex harmonic analysis, then angular deviation can be minimized, but processing time increases
Solution Approach 1:
The patent applies preliminary action by determining correction values for gain and orthogonality errors in advance through harmonic analysis of the evaluation signal. By pre-calculating these correction values based on the characteristic angular deviations, the system prepares compensation data before actual measurement operations, thereby minimizing processing time during real-time angular position determination while maintaining high measurement 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 method effectively compensates for angular errors caused by misalignment, tilting, and other factors, improving the precision of angular measurements and reducing manufacturing and assembly requirements, thereby lowering production costs.
Implementation Method 1
Using a forcibly guided mechanical movement, a sine signal and a cosine signal are generated in the magnetic field sensors
Implementation Method 2
at least two magnetic field sensors to generate sine and cosine signals
Implementation Method 3
an evaluation signal corresponding to the angular values is formed using an arc tangent function
Implementation Method 4
the values for correcting gain errors and/or values for correcting orthogonality errors are ascertained by determining a second harmonic for the evaluation signal and/or a third harmonic for the signals
Data Source
AI summary
A method for compensating angular errors when determining angular values of an arrangement with a permanent magnet and at least two magnetic field sensors. An evaluation signal corresponding to the angular values is formed from the two signals using an arc tangent function. Arrangement errors and errors of a measurement and evaluation unit change the shape of the evaluation signal and lead to an angular deviation in the evaluation signal. In order to minimize the angular deviation, values for correcting gain errors and/or values for correcting orthogonality errors of the signals are changed and values for the gain errors and/or values for correcting orthogonality errors are ascertained by determining a second harmonic in the evaluation signal and/or a third harmonic in the signals and/or density differences of measurement points of a Lissajous curve.