Position Detection System Using Inertial and Distance Sensors
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Solution Overview
Problem
In position detection systems for mobile bodies in warehouses, the accumulation of errors in inertial sensor positioning results leads to significant inaccuracies as the mobile body moves, causing the system to incorrectly adopt positions based on inertial sensor data even when the distance sensor provides a closer actual position.
Innovation Solution
A position detection system that combines inertial and distance sensors by determining a first arrival position based on movement history and a second arrival position based on separation distances, with a range value that adjusts according to the error level of the inertial sensor, allowing for accurate position determination by comparing these positions and switching between them based on relative distance within a dynamic range value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a position detection system uses only an inertial sensor to detect movement history, then the system can operate without GPS or external infrastructure, but the positioning accuracy deteriorates as the mobile body moves further from the starting point due to error accumulation
Solution Approach 1:
The patent combines an inertial sensor that detects movement history with a distance sensor that measures separation distances to multiple fixed stations. The position determination unit integrates both data sources, using the inertial sensor for continuous tracking and the distance sensor for periodic correction, thereby merging the advantages of both systems to maintain accuracy over longer distances.
Solution Approach 2:
The system uses distance measurements from fixed stations to provide feedback on positioning accuracy. When the relative distance between inertial-based position and distance-based position exceeds a threshold, the system detects this as an accuracy degradation and triggers a correction by prioritizing distance sensor data, creating a feedback loop that maintains positioning accuracy.
2Measurement precision
If the system switches to distance sensor-based positioning when inertial sensor error is high, then positioning accuracy is improved, but the system complexity increases due to needing to compare and switch between multiple positioning methods
Solution Approach 1:
The system changes the parameter of position determination methodology based on the relative distance between inertial-based position and distance-based position. When this relative distance is within a threshold, the system uses inertial sensor data; when it exceeds the threshold, it switches to distance sensor data. This dynamic parameter change optimizes accuracy while managing complexity through clear switching criteria.
3Measurement precision
If the system continuously compares positions from inertial and distance sensors, then positioning accuracy is maintained, but the computational load and processing time increase
Solution Approach 1:
The system performs partial comparison by only fully processing distance sensor data when the relative distance exceeds a threshold. During normal operation when accuracy is sufficient, the system relies primarily on inertial sensor data with minimal intervention, reducing computational load while maintaining accuracy when needed.
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 enables accurate detection of the mobile body's position by dynamically adjusting the range value based on movement history, reducing errors and ensuring accurate positioning even as the mobile body moves further, thereby improving the overall accuracy of the system.
Implementation Method 1
a sensor unit including an inertial sensor that detects movement history of a mobile body
Implementation Method 2
a distance sensor that detects separation distances between the mobile body and the fixed stations
Data Source
AI summary
A position detection system according to an embodiment of the present invention includes a plurality of fixed stations 20; and a sensor unit 10 including an inertial sensor that detects movement history of a mobile body 51 and a distance sensor that detects separation distances between the mobile body 51 and the fixed stations 20. A position of the mobile body 51 is determined by detecting a first arrival position P1 obtained based on the movement history, a second arrival position P2 obtained based on the separation distances, and a relative distance L1 between the first arrival position P1 and the second arrival position P2, and by comparing a range value R1 obtained based on the movement history with the relative distance L1. The range value R1 is changed based on the movement history.