Multi-Reference Vector Orientation Estimation for IMU Accuracy
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Solution Overview
Problem
Inertial measurement units (IMUs) using single-reference vectors face accuracy issues when estimating orientations away from the zero orientation due to sensor error and illinearity, leading to diminished accuracy.
Innovation Solution
A multi-reference vector system is implemented, where reference vectors are selected from a stored set based on comparison with check vectors to provide accurate orientation estimates for various orientations, using a controller and computer-readable code to determine and compare sensed vectors with check vectors, and select the closest match to estimate the orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reference vector is used for orientation estimation, then the device complexity is low, but the measurement precision deteriorates when the sensor is in non-zero orientations
Solution Approach 1:
The single reference vector is segmented into multiple reference vectors, each associated with a specific check vector representing a particular orientation. This segmentation allows the system to select the most appropriate reference vector based on the current sensed orientation, thereby maintaining measurement precision across different orientations while managing complexity through structured organization.
Solution Approach 2:
The system dynamically selects the appropriate reference vector based on the current sensed orientation by comparing it with stored check vectors. This dynamic adaptation ensures that the most accurate reference vector is used for each orientation, resolving the contradiction between maintaining low complexity and achieving high measurement precision across varying orientations.
2Measurement precision
If multiple reference vectors are stored and selected dynamically, then the measurement precision improves for various orientations, but the device complexity increases
Solution Approach 1:
Multiple reference vectors and their associated check vectors are pre-calculated and stored in a lookup table during the calibration phase. This preliminary action eliminates the need for complex real-time calculations during operation, allowing the system to achieve high measurement precision through simple comparison and selection operations, thereby managing device complexity effectively.
Solution Approach 2:
The system creates multiple copies of reference vectors for different orientations and stores them in a lookup table. During operation, the appropriate copy is selected based on the current orientation rather than calculating from scratch. This copying approach maintains high measurement precision while reducing computational complexity during runtime.
3Ease of operation
If a single reference vector is used, then the ease of operation is high, but the reliability of orientation estimation deteriorates away from zero orientation
Solution Approach 1:
The system dynamically adapts the reference vector selection based on the current sensed orientation. By comparing the sensed vector with stored check vectors and selecting the closest match, the system maintains high reliability across different orientations while keeping the operation relatively simple through automated selection algorithms.
Solution Approach 2:
The system uses feedback from the comparison between sensed vectors and stored check vectors to automatically select the most appropriate reference vector. This feedback mechanism ensures reliable orientation estimation across various orientations without requiring manual intervention, maintaining ease of operation while improving reliability.
Data Source
AI summary
Physical sensor devices, methods, and computer useable mediums for estimating an orientation of a physical sensor device are disclosed. According to one embodiment, a method for estimating an orientation of a physical sensor device includes determining a sensed vector associated with a physical sensor and comparing the at least one sensed vector to at least a portion of a plurality of check vectors. Each check vector corresponds to an orientation of the physical sensor device. A reference vector is associated with each check vector, thereby defining a plurality of reference vectors. The method further includes selecting at least one check vector that is closest to the at least one sensed vector, selecting a selected at least one reference vector associated with the selected at least one check vector, and estimating the orientation of the physical sensor device based at least in part on the selected at least one reference vector.