Traveling Vehicle System Time-Division Communication Cycle

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Solution Overview

Problem

Existing systems for controlling multiple traveling vehicles via a wireless LAN face delays in communication, which affect real-time control and require reduced velocities, and there is a need for efficient communication and position reporting to maintain accurate relative positions between vehicles.

Innovation Solution

The system employs a control cycle with distinct instruction and report time zones, where traveling vehicles transmit confirmation signals only during instructions and report positions during designated time slots, using a synchronized clock to prevent interference and ensure timely data transmission, allowing the system server to determine and transmit target positions efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If wireless LAN is used for communication between system server and traveling vehicles, then system coverage and flexibility are improved, but communication delays occur affecting real-time control

Engineering Contradiction:
Improvesystem coverageVSAvoidcommunication delay
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The communication cycle is segmented into distinct instruction time zones and report time zones. During instruction time zones, access points transmit instructions to vehicles while vehicles remain silent. During report time zones, vehicles transmit reports to access points. This time-division segmentation prevents communication collisions and reduces delays, enabling real-time control while maintaining wireless LAN coverage flexibility.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If multiple traveling vehicles communicate simultaneously with access points, then system capacity is improved, but communication collisions occur causing delays

Engineering Contradiction:
Improvenumber of vehiclesVSAvoidcommunication collision delay
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The system implements periodic communication cycles with alternating instruction and report time zones. Each vehicle communicates only during its assigned time zone, creating a periodic pattern that prevents collisions. This allows multiple vehicles to operate simultaneously without interference, increasing system capacity while eliminating collision-induced delays.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If vehicles transmit reports continuously, then position accuracy is improved, but communication bandwidth is consumed affecting overall system performance

Engineering Contradiction:
Improveposition accuracyVSAvoidcommunication efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

Vehicles transmit position reports periodically during designated report time zones rather than continuously. The report frequency matches the control cycle period, providing sufficient position accuracy for control decisions while dramatically improving communication efficiency by eliminating redundant transmissions during instruction time zones.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2357543B1Traveling vehicle system and communication method in the traveling vehicle system
Publication Date: 2016.12.07 MURATA MASCH LTD
  • EP2357543B1 patent drawingFigure 1
  • EP2357543B1 patent drawingFigure 2
  • EP2357543B1 patent drawingFigure 3

AI summary

A system server and access points are connected through a LAN on the ground. A control cycle is divided into an instruction time zone for providing instructions from the access points (8) to traveling vehicles (12), and a report time zone for providing reports from the traveling vehicles to the access points. The access points transmit target positions in the instruction time zone, and the traveling vehicles report positions in the report time zone. The system server determines target positions based on the reported positions.