Variable Offset Antenna Array for AGV Guidance

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Solution Overview

Problem

Conventional automated guided vehicle (AGV) guidance systems are limited in handling asymmetrically shaped loads and require additional space and human intervention due to their inability to accurately track an in-floor guidance wire at offset positions, leading to inefficiencies and increased costs in storage and maintenance.

Innovation Solution

The implementation of an onboard programmable microprocessor that analyzes the relative strength of signal outputs from multiple inductor coils to determine the precise position of the AGV relative to the guidance wire, allowing for dynamic offset tracking and simultaneous use of front and rear antennas for improved steering and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional AGV guidance systems use a single antenna or pair of antennas centered on the AGV, then the system structure is simple, but the AGV cannot efficiently transport asymmetrically shaped loads and requires additional space

Engineering Contradiction:
Improveability to handle asymmetrically shaped loadsVSAvoidantenna configuration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The antenna is divided into multiple inductor coils arranged in an array across the width of the AGV. Each coil can independently detect magnetic field strength, allowing the system to determine the AGV's lateral position relative to the guidance wire with high precision. This segmentation enables the AGV to transport asymmetrically shaped loads by dynamically adjusting its offset position from the centerline.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically selects which antenna (front or rear) is active based on the AGV's direction of travel. The microprocessor determines the leading antenna and uses only that antenna's coil array for guidance, allowing the AGV to maintain optimal offset positioning for asymmetric loads while moving in either direction along the guidance wire.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If the AGV uses only the front antenna for guidance, then the system is simple to operate, but the AGV cannot accurately track at offset positions when transporting asymmetric loads

Engineering Contradiction:
Improveposition tracking accuracyVSAvoidguidance system operation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The microprocessor continuously monitors the output signals from all inductor coils in the active antenna array and dynamically adjusts the AGV's lateral position to maintain the desired offset from the guidance wire. This feedback mechanism enables precise tracking of offset positions while the system automatically determines which antenna is leading based on travel direction.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the operational parameters of the antenna system by selectively activating either the front or rear antenna based on the AGV's direction of travel. The microprocessor identifies the leading antenna and configures its coil array to provide the appropriate offset positioning signals, maintaining measurement precision without complicating operation.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional systems use subtractive output analysis of coil signals, then the system is simple to implement, but reliability issues occur due to variations in magnetic field strength

Engineering Contradiction:
Improveguidance system reliabilityVSAvoidsignal processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the conventional subtractive output analysis method with a microprocessor-based signal processing system. The microprocessor reads the raw output signals from all inductor coils, determines the leading antenna, and uses the signals from the coil array to calculate the AGV's lateral position relative to the guidance wire. This substitution improves reliability by eliminating the weaknesses of subtractive analysis while the microprocessor handles the increased processing complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If the AGV requires human intervention when off the guidance wire, then the system is simple to control, but productivity decreases due to stopped operations

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidautonomous recovery capability
Core Design Contradiction:
ProductivityVSExtent of automation

Solution Approach 1:

The AGV system performs self-service by automatically detecting when it has drifted from the desired offset position using the inductor coil array, and autonomously correcting its position without human intervention. The microprocessor continuously monitors coil outputs and adjusts steering to maintain the correct lateral position, enabling continuous operation and eliminating productivity losses from manual intervention.

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

This solution enables AGVs to efficiently transport asymmetrically shaped items without expanding the transport aisle width, reduces the need for human intervention, and decreases construction and maintenance costs by allowing for more precise and flexible navigation within existing infrastructure.

Implementation Method 1

Each guidance antenna for the AGV contains two inductor coils, which individually generate an output voltage based upon the coil's proximity to the magnetic field generated by the frequency carrying guidance wire

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2387738B1Variable offset positioning antenna array for enhanced guidance of automated guided vehicles (AGVS)
Publication Date: 2014.07.09 BOOMERANG SYSTEMS INC
  • EP2387738B1 patent drawingFigure 1~2B
  • EP2387738B1 patent drawingFigure 3~4F
  • EP2387738B1 patent drawingFigure 5A~5C

AI summary

A Variable Offset Positioning Antenna Array for Enhanced Guidance of Automated Guided Vehicles (AGVs) in automated warehousing or storage systems for automobiles or the like, includes two or more inductor coils producing output as a result of interaction with a guidance wire located in or near the surface of the floor which is energized by a frequency generator, and an on board programmable microprocessor which processes the coil output to determine an exact position of the antenna array relative to the guidance wire. In one embodiment, the antenna array enables an AGV to follow a guidance wire at an offset to the direction of travel in order to allow automated storage and retrieval systems to handle asymmetrical items, such as automobiles, more efficiently and cost effectively by decreasing the building space required for travel aisles, vertical conveyors and storage locations as well as decreasing total individual item processing time.