Inertial Sensor Drift Correction via Zero-Angular-Velocity Feedback
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Solution Overview
Problem
Inertial sensors accumulate significant errors due to drift, especially when integrating acceleration over time, leading to inaccuracies in tracking motion trajectories, as existing correction methods only address velocity being zero across all axes, failing to account for errors during periods of non-zero velocity.
Innovation Solution
The method involves sensing zero-angular-velocity instances about an arbitrary axis using an inertial sensor, calculating motion velocity, and correcting it for each interval between these instances, thereby eliminating gravitational acceleration and integrating motion acceleration to improve trajectory tracking accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If integration of acceleration is performed to calculate position, then position information can be obtained, but drift accumulation causes large errors in position calculation
Solution Approach 1:
The patent uses angular velocity sensor feedback to detect when the object is stationary (angular velocity = 0) and corrects the integrated position at these moments. This feedback mechanism allows the system to identify and correct drift accumulation without requiring continuous external reference signals, thereby improving position calculation accuracy while managing drift errors.
Solution Approach 2:
The patent performs preliminary correction of position data by detecting zero-angular-velocity instances before the drift accumulation becomes significant. By correcting the integrated position at these predetermined moments, the system prevents large errors from developing during subsequent integration periods, maintaining measurement precision over extended durations.
2Measurement precision
If correction is performed only when velocity is zero across all axes, then some error reduction is achieved, but errors continue to accumulate during non-zero velocity periods
Solution Approach 1:
The patent applies partial correction by utilizing only the angular velocity component (rather than requiring all three linear velocity components to be zero). This partial action approach allows the system to perform corrections more frequently during motion periods, reducing the time windows in which errors can accumulate and thereby improving overall trajectory tracking accuracy without requiring complete motion cessation.
3Duration of action of moving object
If inertial sensor is used for continuous motion tracking, then continuous position information can be obtained, but drift causes increasing error over extended periods
Solution Approach 1:
The patent implements a feedback-based correction system that continuously monitors angular velocity and triggers position corrections whenever the object comes to a stop (angular velocity = 0). This feedback mechanism enables the system to maintain measurement precision over extended tracking durations by periodically resetting accumulated drift errors without interrupting the continuous tracking operation.
Solution Approach 2:
The patent performs preliminary position corrections at predetermined zero-angular-velocity moments during continuous tracking. By acting in advance at these natural pause points in motion, the system prevents drift from accumulating to large values over extended periods, thereby maintaining both continuous tracking capability and position accuracy.
Data Source
AI summary
An apparatus for correcting an inertial sensor includes an inertial sensor module, a storage module and a control module. The inertial sensor module measures angular velocity and acceleration of an object moving in a space. The storage module stores predetermined operation information and parameters required to correct the measured acceleration. The control module calculates motion velocity from the measured acceleration using the operation information and the parameters, and corrects the calculated motion velocity for each interval between zero-angular-velocity time instances at which angular velocity about an arbitrary axis is “0”.