Chapter 8 - Entity Transfer - College of Engineering：8章-實(shí)體轉(zhuǎn)讓工程學(xué)院

1、EntityTransferChapter 8Simulation with Arena, 3rd ed.rd ed.1What Well Do .Types of Entity TransfersModel 8-1: Resource-Constrained TransfersModels 8-2, 8-3: TransportersConveyorsModel 8-4: Non-accumulatingModel 8-5: AccumulatingSimulation with Arena, 3rd ed.rd ed.2Types of Entity Transfers So FarCon

2、nectZero-delayRouteNon-zero-delay constant, r.v., expressionStations, animated RoutesFixed routes vs. entity-dependent SequencesConnect and Route both assume:No limit on number in transit at a timeEntities have their own feetSimulation with Arena, 3rd ed.rd ed.3New Types of Entity TransfersResource-

3、constrained transfersLimit total number of entities in transit at a timeEntities still have their own feetTelecommunications (number of packets),logistics (number of vehicles)Material-handling devicesTransporters fork lifts, trucks, carts, wheelchairsUsually place limits on numbers, capabilities of

4、transportersLike a Resource, except moveableConveyorsBelts, hook lines, escalatorsUsually limit space on conveyor, speedNon-accumulating vs. accumulatingSimulation with Arena, 3rd ed.rd ed.4Problem 7.8 (HW5)Original systemAssumed all transfer times = TRIA(8,10,12) keep (for now)Parts have their own

5、feet keep (for now)No limit on number of parts in transit at a time dumpNow no more than 4 parts can be in motion at a given timeIf other parts are ready to go, they must wait until theres room to goModel via existing constructs think creativelyModel “space” on the “road” as a ResourceLimit the numb

6、er of Units of this ResourceEntity must Seize unit of “space” resource before beginning trip, Release it at end of tripSimulation with Arena, 3rd ed.rd ed.5Two Ways to Model Resource-Constrained TransfersBoth use a new Transfer Resource representing space on the transitwaysCapacity set to 4 in Resou

7、rce data moduleMaybe the most obvious way (but wont do) Before each Route module insert a Seize module to Seize one unit of Transfer (queue, priority details see text)After each Station module insert a Release module to free up one unit of TransferSimulation with Arena, 3rd ed.rd ed.6Two Ways to Mod

8、el Resource-Constrained Transfers (contd.)Different way (will do, to illustrate new modules, set up for transporters and conveyors) Replace Route modules with Leave modules (Advanced Transfer panel)Transfer Out: Seize unit of Transfer resource before leaving stationResource, Resource Set, particular

9、 member of a Resource SetCan specify prioritiesAlso contains the Route operationGet individual queues, with animation, for parts waiting to goReplace Station modules with Enter modules (Advanced Transfer panel)Defines the StationOption of an unload Delay time (0 for this model)Transfer In: Release T

10、ransfer resourceEffect slight increase in cycle times in systemSimulation with Arena, 3rd ed.rd ed.7Arena Module PicturesRemove allRoute modulesand replace with Leavemodules.Simulation with Arena, 3rd ed.rd ed.8Arena Module Pictures cont.Remove allStation modulesand replace with Enter modules.Simula

11、tion with Arena, 3rd ed.rd ed.9Transporter ConceptsCarts, fork lifts, trucks, wheelchairs, people, When entity is ready to go somewhere, it needs to be “picked up” and movedUse Transporters “moveable” resourcesActivities: Request, Transport, FreeTransporter Selection Rule: If 1 transporter is availa

12、ble when RequestingWhen freed and 1 entity is waiting: Priorities, closest oneTwo types of TransportersFree-Path (well do)Travel time depends only on velocity, distanceIgnore “traffic jams” and their resulting delaysGuided (wont do)AGVs, intersections, etc.Simulation with Arena, 3rd ed.rd ed.10Probl

13、em 7.8 with TransportersHave four carts to transport partsA cart can carry one part at a timeCarts move at 50 feet/minuteWill need to specify accurate distances between StationsIt takes 0.25 minute to load part on a cart, 0.25 minute to unload it from a cartModify problem 7.8 to include carts.Simula

14、tion with Arena, 3rd ed.rd ed.11Problem 7.8 with Transporters (contd.)Create Transporter in Transporter data module (Advanced transfer panel)Name = Cart, Capacity = 4, Velocity = 50Default the Distance Set (later), Units = Per Minute, Initial PositionsMind the units consistency here, in Distance Set

15、 (later)Animation picture for Cart Transporter (similar to creating animations of resources)Transporter button , Animate Transfer toolbarIdentifier = Cart, pictures for Idle, Busy, Inactive statesDraw or copy from .plb picture librariesRide point (details in book)Drop it anywhere in flowchart view (

16、hidden during run)Simulation with Arena, 3rd ed.rd ed.12Problem 7.8 with Transporters (cont.)Simulation with Arena, 3rd ed.rd ed.13Problem 7.8 with Transporters (contd.)Request a Cart modify existing Leave modulesDelay = 0.25 Minute for load timeTransfer Out = Request TransporterTransporter Name = C

17、artSelection Rule = Smallest DistanceApplies when 1 transporter is availableOthers: Cyclic, Random, Preferred Order, Largest Distance (?)Save Attribute = Cart # (remember which cart for later)Connect Type = TransportMove Time disappears determined by Velocity, Distances (later)Station Type = Sequenc

18、eInstead of Leave: Request-Delay-TransportMore complex, more flexible book has details, examplesSimulation with Arena, 3rd ed.rd ed.14Problem 7.8 with Transporters (contd.)Change allLeave modules.Simulation with Arena, 3rd ed.rd ed.15Problem 7.8 with Transporters (contd.)Free the Cart modify existin

19、g Enter modulesDelay = 0.25 Minute for unload timeTransfer In = Free TransporterTransporter Name = CartUnit Number = Cart # attribute of part entityInstead of Enter: Station-Delay-FreeMore complex, more flexible book has details, examplesSimulation with Arena, 3rd ed.rd ed.16Problem 7.8 with Transpo

20、rters (contd.)Change allEnter modules.Simulation with Arena, 3rd ed.rd ed.17Distances for TransportersDefine contents of Distance Set Distances (in feet) moved by parts:Blank cells: part movements that dont occurEnter these data in Distance data module (Advanced Transfer panel)Name = Stations button

21、, add rows with Beginning Station, Ending Station, Distance for above dataDirection is implied; could be asymmetricUnits!Units!Simulation with Arena, 3rd ed.rd ed.18Transporter Distances (cont.)Simulation with Arena, 3rd ed.rd ed.19Animating Transporter MovementAdd distances to animationDelete all t

22、he old Route Path animation objectsBut leave the Station animationsAdd animated transporter distances with Distance button , Animate Transfer toolbarDialog, placement similar to Route PathsIdentifier = Click in Beginning Station marker, intermediate clicks, Ending Station markerOptions for Rotate, F

23、lipGrid, Snap to help place animated transporter distancesSimulation with Arena, 3rd ed.rd ed.20Parking Areas for TransportersAnimate transporters when theyre freeParking button , Animate Transfer toolbarLike a Queue animation Point vs. Line, Shift, RotateCursor becomes cross hairs, click near lower

24、 left of Station marker to start, click for first Point or head of LineMore clicks for more Points (double-click to end), or second click to end LineWant enough points/space for all transporters (2 here)Repeat for all Stations where Transporters could be freedSimulation with Arena, 3rd ed.rd ed.21Mo

25、re Distances Empty TransportersAbove Distances incomplete only for part movements along their sequencesTransporters must also move when empty (deadheading)In general, n(n - 1) distances need definition for network with n nodesSome not possible Order Release to Exit System14 more distances to define

26、in Distances data module (not grayed):Previous slide with picture of distance spreadsheet shows all 30 distances.Simulation with Arena, 3rd ed.rd ed.22ConveyorsReplace Transporters with a conveyorLoop conveyor to follow main path, clockwiseSix entrance/exit pointsLoad, Unload takes 0.25 minuteEach p

27、art is 1 foot per side, but want 2 feet of conveyor space for clearance on cornersSpeed = 30 feet/minuteDistances: Assume all to be 100 feet.For Problem 7.8, we need to change sequences slightly in order to use conveyors because they only move in one direction.Units!Simulation with Arena, 3rd ed.rd

28、ed.23Problem 7.8 Sequence Changes to prepare for Conveyor ModelingPart 1 Sequence StepsPart 2 Sequence StepsPart 3 Sequence StepsPart 4 Sequence StepsPart 5 Sequence StepsNote: Only need to change station names at each step. (No need to change assignments at each step.)Simulation with Arena, 3rd ed.

29、rd ed.24Conveyor ConceptsEntity to be conveyed must wait for spaceConveyor consists of cellsEqual size, constantly moving think of a narrow escalatorEntities might require multiple contiguous cellsMust define cell size; tradeoff involved:Small cells: accurate model but slow executionLarge cells: jus

30、t the opposite!Entities Access space, Convey, and ExitConveyor = series of linear SegmentsEach segment starts and ends at a StationLink to form loops, diverge points, converge pointsSimulation with Arena, 3rd ed.rd ed.25Types of ConveyorsBoth travel in a single, irreversible directionNonaccumulating

31、: belt, bucket line, escalatorSpacing between entities on it doesnt changeEntire conveyor stops for entity Access/Exit if Load/Unload time is 0Accumulating: rollers, freewayConveyor never stops movingIf entity on it stops to Exit, other entities behind it are blocked and bunch up (entities ahead of

32、it keep moving)When blockage ends, blocked entities go on but maybe not all at once (spacing requirements)Simulation with Arena, 3rd ed.rd ed.26Problem 7.8 modeling with ConveyorsModify 7.8 (with sequences modified as shown in slide 24)Delete all the Transport Paths and Distances.Define Conveyor via

33、 Conveyor data module, Advanced Transfer panelConveyer = Loop ConveyorSegment Name = Type = Non-AccumulatingVelocity = 30 (feet), Units = Per MinuteCell Size = 2 (feet)Max Cells Occupied = 1 (cell per entity)Units!Units!Simulation with Arena, 3rd ed.rd ed.27Problem 7.8 modeling with Conveyors (cont.

34、)Simulation with Arena, 3rd ed.rd ed.28Problem 7.8 modeling with Conveyors (cont.)Change each Leave moduleDelay =0.25, Units = MinutesTransfer Out = Access ConveyorConveyor Name = Loop Conveyor# of Cells = 1Connect Type = ConveyChange each Enter moduleDelay = , Units = MinutesTransfer In = Exit ConveyorConveyor Name = Loop ConveyorSimulation with Arena, 3rd ed.rd ed.29Problem 7.8 modeling with Conveyors (cont.)Modify all Leav