Gyroscope Scale Calibration Using Magnetometer Rotation
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Solution Overview
Problem
Gyroscopes in devices like robotic vacuum cleaners face challenges in maintaining accurate angular velocity measurements due to biases and scale calibration issues, which are difficult to address through traditional factory calibration methods, especially under changing environmental conditions.
Innovation Solution
A method involving a gyroscope and magnetometer combination, where the device performs multiple rotations to collect magnetic field measurements, allowing for on-board calibration of the gyroscope scale using a calibration device, thereby compensating for biases and adapting to environmental changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional factory calibration methods are used, then initial calibration can be performed, but the gyroscope cannot adapt to changing environmental conditions and maintains inaccurate measurements over time
Solution Approach 1:
The patent implements dynamic calibration by continuously monitoring gyroscope readings against magnetometer data during device rotation. The system automatically adjusts calibration parameters in real-time based on observed deviations, transforming the static factory calibration into a dynamic process that adapts to environmental changes and maintains measurement accuracy over time.
Solution Approach 2:
The system uses feedback from comparing gyroscope and magnetometer measurements to identify calibration drift. By continuously monitoring the relationship between these sensor readings during rotation operations, the system detects deviations and automatically corrects them, creating a closed-loop calibration process that maintains reliability under varying environmental conditions.
2Adaptability or versatility
If on-board calibration using magnetometer measurements is implemented, then adaptability to environmental changes is improved, but device complexity increases
Solution Approach 1:
The patent merges the calibration function with existing navigation operations by combining gyroscope and magnetometer data processing into a unified system. The calibration algorithm is integrated into the existing sensor fusion pipeline, allowing calibration to occur during normal device operation without adding separate calibration hardware or significantly increasing system complexity.
Solution Approach 2:
The system performs self-calibration by automatically using its own sensor data (magnetometer and gyroscope readings) to adjust calibration parameters. This self-service approach eliminates the need for external calibration equipment or manual intervention, reducing operational complexity while maintaining adaptability to environmental changes.
3Measurement precision
If multiple rotations with magnetic field measurements are performed for calibration, then calibration accuracy is improved, but calibration time and computational requirements increase
Solution Approach 1:
The patent applies partial action by performing calibration using a subset of rotation cycles rather than requiring exhaustive calibration data. The system identifies sufficient calibration information from a limited number of rotation measurements, achieving adequate calibration accuracy without the time cost of complete calibration procedures, thus balancing precision requirements with time constraints.
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 enhances the accuracy of gyroscope readings by dynamically calibrating the scale factor, improving reliability and adaptability to environmental fluctuations, reducing the need for costly factory calibration and maintaining accuracy over time.
Implementation Method 1
a scale of a gyroscope may be calibrated using plural magnetic field measurements (e.g., in a range of about 10 to 12 field measurements) acquired during one or more successive rotations
Data Source
AI summary
Methods, apparatus, and systems for estimating and calibrating a gyroscope's scale using a magnetometer mounted on the same device by rotating the device about an axis multiple times; and, during the first rotation, storing the magnetometer magnetic field reading and a heading (from integration of the gyroscope readings) at each of a plurality of angular reference points; then, during each subsequent rotation, determining magnetometer/gyroscope-heading output pairs for which the magnetometer output matches the magnetometer reading corresponding to one of the reference points, thereby indicating that the device has reached the same heading as the matching reference point; then, for each matching output sample pair, using that magnetometer/gyroscope-heading output sample pair to update the gyroscope scale factor for the corresponding angular reference point; and averaging those scale estimates to generate a final gyroscope scale factor estimate.