Rack Leg Identification for Warehouse Vehicle Localization Calibration

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Solution Overview

Problem

Existing localization systems for industrial vehicles in warehouse environments face challenges in accurately tracking and navigating within aisles due to variations in rack spacing and alignment, leading to inefficiencies and potential collisions.

Innovation Solution

Utilizing a rack leg imaging module equipped with a camera and infrared illuminators to capture images of upright rail rack legs, combined with a control module and odometry data, to enhance localization accuracy and maintain vehicle position within the warehouse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional localization systems are used in warehouse environments, then vehicle navigation is enabled, but localization accuracy deteriorates due to variations in rack spacing and alignment

Engineering Contradiction:
Improvelocalization accuracyVSAvoidtracking reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces rack legs as intermediary reference objects between the localization system and the varying rack structures. By attaching identifiable markers to rack legs and using them as intermediate reference points, the system can accurately track vehicle position even when rack spacing and alignment vary, thus resolving the contradiction between measurement precision and reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system creates a virtual copy or map of the warehouse environment by recording the positions and identifiers of rack legs. This copied reference framework allows the localization system to compare actual sensor readings against the stored map, maintaining accurate localization despite physical variations in the warehouse structure

Inventive Principle:
Principle #26Copying

2Measurement precision

If rack leg identification is implemented for precise localization, then vehicle position tracking is improved, but system complexity increases due to additional imaging and processing requirements

Engineering Contradiction:
Improveposition tracking accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The imaging module serves multiple functions: capturing rack leg images for localization, identifying unique markers, and providing feedback for position correction. By making the imaging system multi-functional, the patent achieves precise position tracking without proportionally increasing system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the existing warehouse rack structure itself as the reference framework, eliminating the need for separate, dedicated positioning infrastructure. The rack legs and their markers serve the dual purpose of their original function and localization reference points, reducing overall system complexity while maintaining high precision

Inventive Principle:
Principle #25Self-service

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

Improves localization accuracy and reduces downtime by enabling precise tracking of industrial vehicles within warehouse aisles, ensuring efficient navigation and collision avoidance.

Implementation Method 1

a rack leg imaging module equipped with a camera and infrared illuminators

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Data Source

PatentEP3921712B1Systems and methods for out of aisle localization and vehicle position calibration using rack leg identification
Publication Date: 2026.01.28 CROWN EQUIP CORP
  • EP3921712B1 patent drawingFigure 1A
  • EP3921712B1 patent drawingFigure 1B
  • EP3921712B1 patent drawingFigure 2

AI summary

A materials handling vehicle includes a camera, odometry module, processor, and drive mechanism. The camera captures images of an identifier for a racking system aisle and a rack leg portion in the aisle. The processor uses the identifier to generate information indicative of an initial rack leg position and rack leg spacing in the aisle, generate an initial vehicle position using the initial rack leg position, generate a vehicle odometry-based position using odometry data and the initial vehicle position, detect a subsequent rack leg using a captured image, correlate the detected subsequent rack leg with an expected vehicle position using rack leg spacing, generate an odometry error signal based on a difference between the positions, and update the vehicle odometry-based position using the odometry error signal and/or generated mast sway compensation to use for end of aisle protection and/or in/out of aisle localization.