Posture Estimation Device Yaw Correction via Representative Plane
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Solution Overview
Problem
Conventional posture estimation technologies using IMU sensors face challenges in accurately estimating yaw direction due to geomagnetic disturbances, leading to reduced estimation accuracy and inability to correct unnatural joint displacements in real time.
Innovation Solution
A posture estimation device and method that integrates angular velocities and accelerations from multiple sensors, converts data into a standard coordinate system, and corrects angular velocities using a representative plane to align the normal line with perpendicular orientations, reducing the impact of geomagnetic interference and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If geomagnetic sensor is used for yaw direction correction, then posture estimation accuracy in yaw direction is improved, but reliability deteriorates due to geomagnetic disturbances from metal objects
Solution Approach 1:
The patent removes the geomagnetic sensor from the system and extracts only the necessary correction functionality. Instead of relying on geomagnetic data, the system uses a method that corrects yaw direction errors by processing data from non-geomagnetic sensors (accelerometers and gyroscopes) through coordinate system transformations and integration, thereby eliminating the reliability issue while maintaining yaw correction capability
Solution Approach 2:
The patent makes the acceleration sensor serve multiple functions: it is used not only for gravity detection and roll/pitch correction but also for yaw direction correction through coordinate system transformation. This multi-functional use of existing sensors eliminates the need for specialized geomagnetic sensors while maintaining comprehensive posture estimation capability
2Manufacturing precision
If posture correction is performed after measurement processing, then unnatural joint displacement is corrected, but productivity deteriorates due to time-consuming processing
Solution Approach 1:
The patent performs coordinate system transformation and angular velocity integration in advance, before final posture calculation. By pre-processing the sensor data to establish a corrected reference frame, the system eliminates the need for time-consuming post-processing corrections, thereby achieving both accuracy and real-time performance
Solution Approach 2:
The system continuously integrates angular velocities and compares the resulting orientation with expected anatomical constraints, applying real-time feedback correction. This closed-loop approach maintains posture accuracy during the measurement process itself rather than requiring separate post-processing steps
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
Enables more accurate and real-time posture estimation even in environments with geomagnetic disturbances, effectively correcting unnatural postures and maintaining estimation accuracy over long periods without relying on geomagnetic data.
Implementation Method 1
inertial measurement unit (IMU) sensors (inertial measurement sensors) configured to measure an angular velocity and an acceleration
Implementation Method 2
an azimuth is measured by a geomagnetic sensor
Data Source
AI summary
A posture estimation device includes an acquisition part acquires information of angular velocities and accelerations from a plurality of sensors that detects angular velocities and accelerations and that are attached to a plurality of locations on an estimation object, a conversion part that converts information acquired by the acquisition part into information of a standard coordinate system from a sensor coordinate system, an integrating part that calculates an orientation of a reference area of the estimation object as a part of a posture of the estimation object by integrating the converted angular velocities, and a correction part, assuming a representative plane passing through a reference area included in the estimation object, corrects the converted angular velocities of the reference area so that a normal line of the representative plane and an orientation of the reference area calculated by the integrating part approaches to directions that are perpendicular to each other.