RFID Tag Motion Filtering via Forklift Acceleration
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Solution Overview
Problem
RFID systems face difficulties in accurately determining which tagged items are loaded on forklifts and other mobile vehicles, as they may erroneously read extraneous tags, leading to inaccuracies and the need for a reliable method to distinguish between loaded and unloaded tags.
Innovation Solution
A system that uses forklift motion parameters, such as velocity, acceleration, and jerk, obtained from accelerometers and compared with tag motion parameters using the time domain phase difference of arrival method, to determine if an RFID tag is part of the forklift load, employing a portal reader system and a forklift motion sensor to filter out extraneous tags.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If RFID readers are used to track items on mobile vehicles, then item tracking capability is improved, but measurement precision deteriorates due to erroneous reading of extraneous tags
Solution Approach 1:
The patent introduces motion sensors (accelerometers, gyroscopes, GPS) as intermediary devices that measure the motion of the mobile vehicle and compare it with tag motion parameters. This intermediary measurement system acts as a filter to distinguish between tags that are truly on the vehicle and extraneous tags, thereby resolving the contradiction between tracking capability and identification accuracy.
2Measurement precision
If motion sensors are added to the RFID system, then tag identification accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the mobile vehicle itself serve multiple functions: it acts as both the transport platform and the mounting structure for motion sensors. The motion sensors are integrated into the vehicle's existing structure, and the vehicle's motion serves as the reference frame for tag identification. This multi-functionality approach improves accuracy without proportionally increasing system complexity.
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 effectively differentiates between tags on the forklift and those not in motion with the forklift, reducing errors and providing accurate tracking of loaded items, even in environments with multiple moving vehicles.
Implementation Method 1
RFID systems face difficulties in accurately determining which tagged items are loaded on forklifts and other mobile vehicles
Data Source
AI summary
An RFID system is used to detect whether an RFID tag is part of the load of a forklift or other transport device. In one aspect where the load is in motion relative to an RFID reader system, the RFID system obtains tag readings and derives tag vector motion information which can be compared to the known motion of the load to distinguish tags that are part of the load from false positives which are unavoidably also within the field of the reader system. A forklift antenna system may also make readings from load pickup to load deposit in a truck trailer, and utilize computed tag vector motion information to distinguish tags that are part of the load from false positives. The tag vector information my relate to tag velocity, tag acceleration, and/or rate of change of tag acceleration. The two components of the RFID system may communicate information on identified tags, and/or interact (e.g. by silencing tags), so as to cooperate in identifying true positive tags in the load. A portal or reader system location along the path of the forklift can be activated prior to arrival of the load to eliminate certain false positives from requiring evaluation while the forklift load is moving through the field region of such reader system. Vertical motion of the load can be utilized as a way of discriminating between true positive tags in the load and false positives.