AGV Position Correction Using RFID and SLAM Fusion
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Solution Overview
Problem
Existing AGV systems face challenges in accurately determining their position and azimuth angle due to environmental factors such as contamination, illuminance changes, and interference from forklifts or people, leading to errors in SLAM-based positioning.
Innovation Solution
The system uses RFID tags placed on shelves and walls to partition the travel path, allowing the AGV to read position information using RFID antennas, which corrects the SLAM-estimated position and azimuth angle, ensuring accuracy by integrating this information with SLAM technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SLAM technology is used for position estimation, then the AGV can navigate without guide cables or tapes, but the position estimation becomes inaccurate when environmental maps change or people/forklifts intervene
Solution Approach 1:
The patent introduces RFID tags as intermediary objects placed on shelves and walls to serve as reliable position reference points. These tags mediate between the AGV's SLAM-based position estimation and the actual physical environment, providing stable reference markers that do not change with environmental variations. The RFID tags act as a mediator that corrects SLAM drift by providing known, fixed position references.
Solution Approach 2:
The system implements feedback by continuously comparing the AGV's SLAM-estimated position with the actual position determined from RFID tag readings. When deviations are detected, the system feeds back correction information to adjust the position estimation, creating a closed-loop control system that maintains accuracy despite environmental changes.
2Ease of operation
If guide tapes are attached to the floor or ceiling for AGV navigation, then the AGV can follow the travel path, but the detection fails when the guide tape is damaged or the floor is dirty
Solution Approach 1:
The patent transitions the guidance system from the horizontal plane (floor-mounted guide tapes) to the vertical dimension by placing RFID tags on shelves and walls. This dimensional shift allows the AGV to read position information from elevated surfaces that are less susceptible to floor contamination and damage, improving detection reliability while maintaining ease of travel path guidance.
Solution Approach 2:
The system replaces the mechanical/optical guide tape detection method with an electromagnetic field-based RFID reading system. Instead of relying on visual or mechanical detection of guide tapes that can be damaged or obscured, the AGV uses RFID antennas to read electromagnetic signals from tags, providing more reliable detection that is not affected by physical damage or dirt.
3Measurement precision
If RFID tags are placed on shelves and walls to correct position estimation, then the position accuracy improves, but the system complexity increases due to additional hardware and processing
Solution Approach 1:
The RFID tags serve multiple functions: they provide position reference points for correction, enable identification of specific locations along the travel path, and can potentially store additional information about the environment. This multi-functionality justifies the added hardware by providing several benefits from a single component addition.
Solution Approach 2:
The system changes the parameter of position estimation from purely SLAM-based (prone to drift) to a hybrid approach using RFID tag readings as reference parameters. By introducing these additional reference parameters, the system achieves higher accuracy despite the increased complexity of processing multiple data sources.
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
The system provides highly accurate position and azimuth angle information for the AGV, unaffected by environmental factors, and continuously updates SLAM-based estimates with RFID-tagged data, ensuring precise navigation.
Implementation Method 1
an RFID reader that reads information on positions from the RFID tag
Implementation Method 2
a detection result of the surroundings detection unit that relies on a LiDAR technology
Data Source
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AI summary
The present invention aims to provide an automated guided vehicle (AGV) traveling system capable of accurately grasping the position and the azimuth angle of the AGV by a simple method unaffected by the use environment. The provide AGV traveling system comprises: an AGV; and a travel path along which the AGV travels, wherein the travel path is partitioned by a shelf or a wall; an RFID tag is placed on the shelve or the wall; and the AGV includes: a vehicle body, a drive unit, a control unit that controls the drive unit, a surroundings detection unit that detects an object around the AGV, and an RFID reader having an antenna that reads information on positions from the RFID tag, wherein while the AGV is traveling along the travel path, a detection result of the surroundings detection unit is used to estimate the position and the azimuth angle of the AGV by a SLAM technology, wherein the information on positions are read from the RFID tag of the shelf or wall, wherein based on this information on positions, the position and the azimuth angle of the AVG are estimated, and wherein the position and the azimuth angle of the AVG estimated by the SLAM technologies are corrected by the position and the azimuth angle of the AGV estimated based on the position of the RFID tag.