AGV Wi-Fi Handover Control for Low-Latency Fleet Movement

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Solution Overview

Problem

Existing solutions for managing fleets of autonomous guided vehicles in warehouses face challenges with radio-frequency communication latency and signal handover, leading to potential vehicle stopping or obsolete data usage due to delays in access point transfer and authentication.

Innovation Solution

A method that involves recording access point coordinates and proactively reconnecting to the closest access point if authentication or response times exceed predetermined thresholds, using geolocation means and WiFi communication modules to minimize latency and ensure continuous operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the vehicle uses standard WiFi roaming protocols to switch between access points, then the vehicle can maintain connectivity across the warehouse, but authentication delays cause latency and potential safety stops

Engineering Contradiction:
Improveconnectivity reliabilityVSAvoidauthentication delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-authenticating with target access points before the vehicle actually needs to switch. The supervisory server maintains authentication credentials ready in advance, so when a handover is needed, the vehicle can immediately connect to the pre-authenticated access point without experiencing authentication delays.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system cushions against potential connectivity interruptions by maintaining buffer zones of authenticated access points and pre-establishing connection credentials. This creates a safety margin that prevents latency-induced safety stops by ensuring seamless transitions are already prepared before they become necessary.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Illumination intensity

If the vehicle frequently scans for and switches between access points, then the vehicle can maintain optimal signal strength, but the switching process causes data obsolescence and operational delays

Engineering Contradiction:
Improvesignal strengthVSAvoidoperational efficiency
Core Design Contradiction:
Illumination intensityVSProductivity

Solution Approach 1:

The supervisory server proactively manages access point assignments and pre-coordinates handovers before signal degradation becomes critical. By predicting optimal switch points and pre-authenticating connections, the system maintains signal strength without requiring frequent reactive scanning and switching, thus preserving operational efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms where the supervisory server continuously monitors vehicle position, speed, and signal quality to dynamically adjust handover timing. This feedback loop optimizes the balance between maintaining signal strength and minimizing disruptive switches, preventing both data obsolescence and operational delays.

Inventive Principle:
Principle #23Feedback

3Loss of time

If the vehicle maintains continuous connection to a single access point, then authentication latency is minimized, but the vehicle may lose connectivity when moving between access point coverage zones

Engineering Contradiction:
Improveauthentication latencyVSAvoidconnection continuity
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The system performs preliminary authentication with multiple potential access points along the vehicle's predicted path. The supervisory server pre-establishes credentials with target access points before the vehicle arrives, allowing immediate connection upon entry into coverage zones without authentication delays, thus maintaining both low latency and continuous connectivity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The supervisory server acts as an intermediary that coordinates multiple access points in advance. It manages the authentication state across different access points and orchestrates seamless handovers, ensuring the vehicle maintains continuous connectivity while minimizing authentication latency through coordinated pre-authentication with intermediary access points.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3906711B1Method for the control, by a supervising server, of the movement of a fleet of autonomously guided vehicles
Publication Date: 2023.11.08 BALYO
  • EP3906711B1 patent drawingFigure 1

AI summary

The invention concerns a method for the control, by a supervising server, of the movement of a fleet of autonomously guided vehicles in a movement area equipped with a plurality of wireless Wi-Fi access points each comprising at least one geolocation means and a Wi-Fi communication module, said method comprising a step of recording coordinates of these access points and steps of changing access point, which are executed by each of the autonomously guided vehicles, said steps consisting of controlling the disconnection of the Wi-Fi communication module from the active access point and reconnection to the SSIDi access point for which the coordinates recorded in the database are the closest of the coordinates determined by the geolocation means.