Gyro Sensor Offset Correction via Stationary Detection
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Solution Overview
Problem
Existing offset correction techniques for gyro sensors lack real-time capabilities and accuracy, particularly in scenarios where the movement path is not straight or temperature-dependent tables are used, leading to inaccurate offset value calculations.
Innovation Solution
An offset correction apparatus that includes a gyro sensor, an acceleration sensor, a geomagnetic sensor, and a microcontroller with software units for orientation calculation, stationary determination, and offset value update, which calculates and updates offset values in real time by determining whether the gyro sensor is stationary using acceleration and geomagnetic values, and removes noise by calculating differences in Euler angles over a fixed time period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If output values are stored and corrected in reverse chronological order, then offset correction can be performed, but real-time correction capability is lost
Solution Approach 1:
The patent inverts the conventional correction approach by determining stationarity in real-time and calculating offset values immediately, rather than storing data and correcting retrospectively. This allows the system to compute offset values as they are generated, eliminating the time delay inherent in post-processing approaches while maintaining correction accuracy.
Solution Approach 2:
The patent performs preliminary stationarity determination using acceleration and geomagnetic sensors before proceeding with offset calculation. By pre-identifying stationary periods in real-time, the system prepares the necessary conditions for accurate offset correction without delaying the correction process, thus achieving both accuracy and real-time performance.
2Measurement precision
If a temperature-dependent table is used for candidate correction values, then offset correction can be performed, but device-specific tables must be created and restrictions on movement direction are imposed
Solution Approach 1:
The patent enables the system to self-determine offset values by detecting stationary periods and calculating corrections based on sensor data during those periods. This eliminates the need for pre-created device-specific temperature tables and manual calibration procedures, as the system automatically adapts to its own characteristics through real-time observation and computation.
Solution Approach 2:
The patent changes the approach from using fixed temperature-dependent tables to dynamically calculating offset values based on actual sensor measurements during stationary periods. This parameter change allows the system to adapt to temperature variations and device-specific characteristics without requiring pre-established tables or imposing movement restrictions.
3Productivity
If the assumption of straight path movement is made, then offset correction can be calculated, but accuracy deteriorates when moving along curving paths or swinging
Solution Approach 1:
The patent uses feedback from acceleration and geomagnetic sensors to continuously monitor and determine stationarity. This feedback mechanism allows the system to identify genuine stationary periods regardless of the movement path, enabling accurate offset correction without requiring assumptions about straight-line movement. The feedback loop ensures that corrections are only applied when the device is truly stationary, improving accuracy for curving paths and swinging motions.
Data Source
AI summary
An offset correction apparatus for a gyro sensor includes an acceleration sensor, a geomagnetic sensor, a stationary determination unit that determines, by using an output value of the acceleration sensor and an output value of the geomagnetic sensor, whether the gyro sensor is stationary, a difference calculation unit that calculates an offset value of the gyro sensor by using an output value of the gyro sensor, and an offset-value update unit that assumes, as a new offset value, an offset value calculated by the difference calculation unit by using an output value of the gyro sensor determined to be stationary by the stationary determination unit.