Posture Estimation Using Rotational Acceleration Compensation
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Solution Overview
Problem
Existing posture estimation methods using gyro sensors and accelerometers face inaccuracies due to rotational motion, particularly in dynamic situations, as they fail to accurately determine the center of rotation and posture with high maneuverability, often requiring multiple inertial sensors and suffering from measurement errors from axis misalignment.
Innovation Solution
A processor-implemented method that estimates rotational acceleration based on angular velocity and center of rotation from previous timepoints, corrects acceleration measurements, and determines posture and center of rotation using a Kalman filter-based system model, allowing for accurate posture estimation with a single inertial sensor by setting a small time interval between measurement points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple inertial sensors are used for posture estimation, then measurement precision may be improved, but device complexity increases
Solution Approach 1:
The patent extracts and compensates for the harmful rotational acceleration component from the acceleration sensor measurements. By identifying and removing the rotational motion effect through calculation based on gyro data, the system achieves accurate posture estimation using a single inertial sensor unit, eliminating the need for multiple sensors while maintaining measurement precision.
Solution Approach 2:
The patent uses the gyro sensor as an intermediary to provide angular velocity information that enables the calculation and compensation of rotational acceleration effects on the acceleration sensor. This intermediary data allows the system to correct acceleration measurements without requiring additional inertial sensors, thereby reducing device complexity while preserving accuracy.
2Ease of operation
If traditional posture estimation methods are used in dynamic situations, then ease of operation is maintained, but measurement precision deteriorates due to rotational motion errors
Solution Approach 1:
The patent implements a feedback mechanism where the gyro sensor continuously provides angular velocity information that is used to calculate rotational acceleration, which then feeds back to correct the acceleration sensor measurements in real-time. This feedback loop enables accurate posture estimation during dynamic movements while maintaining the simplicity of using a single integrated sensor unit.
Solution Approach 2:
The patent replaces the need for complex mechanical multi-sensor configurations with a computational approach. By using mathematical calculations to compensate for rotational effects based on gyro data, the system achieves high-precision posture estimation in dynamic conditions without requiring multiple physically aligned inertial sensors, thus maintaining ease of operation.
3Device complexity
If acceleration measurements are not corrected for rotational acceleration, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent performs preliminary calculation of rotational acceleration using gyro data before correcting the acceleration sensor measurements. By pre-computing the rotational component based on angular velocity and its derivative, the system prepares the correction term in advance, enabling accurate acceleration measurement without adding significant processing complexity during the main measurement cycle.
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 posture estimation accuracy in dynamic conditions, reduces errors, and eliminates the need for multiple inertial sensors, enhancing performance in high maneuver situations by accurately calculating rotational acceleration and correcting acceleration components.
Implementation Method 1
The gyro sensor may measure the angular velocity by converting a Coriolis force generated by the rotational motion into an electrical signal
Implementation Method 2
The accelerometer, when in a stationary state, may sense an acceleration of a gravity direction and thus, may measure an acceleration of −g (gravitational acceleration) in the z-axial direction
Data Source
AI summary
A processor-implemented posture determination method includes: estimating a rotational acceleration of a timepoint based on an angular velocity measured by a first sensor at the timepoint and a determined center of rotation of a previous timepoint; correcting an acceleration measured by a second sensor at the timepoint based on the rotational acceleration; and determining a center of rotation of the timepoint and a posture of the timepoint based on the corrected acceleration and an estimated posture of the timepoint.