TIVDM1 Sortation System, Tray Allocation 1

Tray allocation for a sortation system

TI-VDM1 Project

by

José Antonio Esparza

and

Kim Bjerge

TIVDM1 Sortation System, Tray Allocation 2

Contents of presentation

• Sortation System Introduction• Cross-Belt Sorter• Example of sortation systems - video’s• Essential sorter concepts/terminology• Customer requirements• Scope of project – Tray allocation• Induction group – Tray allocation• Tray allocation requirements (R1-R15)

Sortation System Introduction

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Post and parcel sortation

Airport baggage sortation

Cross-Belt Sorter

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Example of sortation systems - video’s

• Crossorter• http://www.youtube.com/watch?v=8FILmtVHCAQ&featu

re=related

• Crossorter for Taxipost (Belgian post)• http://www.youtube.com/watch?v=Zf9zyRkGfDM

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Essential sorter concepts/terminology

• Sorter• The complete sorter system that consist of trays, inductions and discharges

(Machine and control)

• Trays• Transports and sorts items (Parcels, baggage, post…)

• Sorter-ring• Ring of trays that transports items from the induction group to the discharges

• Induction• Inducting items on the sorter-ring

• Induction group• A group of inductions capable filling the sorter-ring with items

• Card reader• Reading the unique identifier of the trays located at the induction group

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Customer requirements

• A sorter system is able to sort items with different size within a minimum and maximum limit

• The sorter must have a maximum throughput of e.g. 20.000 parcels an hour

• These parameters are important for the customer, so they should be able to be customized in the model

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Scope of project – Tray allocation

• The sorter system consist of a number of trays on where a number of inductions are feeding items

• The inductions are grouped being able to overfill the trays and therefore the tray allocation algorithm must be optimize so the maximum throughput is reached without starvation of any inductions in the group

Induction group – Tray allocation

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Sorter ring

Induction group

Inductions

Tray Id. Reader

A simplified sorter model

Induction group – Tray allocation

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Sorter ring

The sorter in action

t0t1t2t3Waiting!

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Tray allocation requirements (R1-R6)

• R1. The sorter-ring moves at a constant speed

• R2. The sorter-ring consist of a number of trays with a certain size

• R3. Trays are consecutively located at the sorter-ring

• R4. All trays has an unique identifier

• R5. Each tray can be occupied at a maximum by one item

• R6. It is possible that the tray is already occupied

Tray allocation requirements (R7-R12)

• R7. Items may present different sizes, from a minimum to maximum size

• R8. The inductions are able to feed the sorter with items at a maximum speed

• R9. The items arrives at the inductions at inconstant frequency

• R10. An item can only be inducted on one or two trays

• R11. There are several inductions per induction group

• R12. There is a card reader for each induction group

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Tray allocation requirements (R12-R15)

• R13. The system should be able to handle sorter capacity based on throughput and item size, in order to compute the tray allocation algorithm

• R14. The tray allocation algorithm may not cause starvation of the inductions

• R15. The tray allocation algorithm must allocate empty trays for the inductions

• R16. It is assumed that all discharges can empty the sorter-ring at any given parameters

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