MCM and MMS by keara

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									Tools for Rapid Simulation Modeling for the „Paper Switching‟ Application
Presented for RASIG by John Carson AutoSimulations

RASIG
Rail Applications Special Interest Group

A Modest Proposal

• AutoMod can do it!

Who is this guy? What is AutoMod?
• AutoSimulations
– founded in 1982 – 108 employees worldwide
• offices in USA, UK, Japan, Taiwan, Singapore • distributors in UK, Europe, Far East, Brazil

– headquarters in Bountiful, Utah – owned by Brooks Automation (almost) – ASI offers simulation and scheduling software, training and consulting – main simulation product: AutoMod

AutoMod
• General purpose simulation package
– strong modern simulation language – runs on Windows

• Templates to facilitate vehicle and material handling applications
– vehicles, conveyors, ASRS, bridge crane, … – “tanks & pipes” for liquid and bulk – vehicle templates can be applied to:
• rail, trucks, ships

• Currently on version 9.0

AutoMod Applications
• “Bread „n butter”
– – – – Manufacturing Warehousing Distribution Centers Transportation/logistics

Transportation Applications
• AutoMod has been used for:
– rail yard simulation
• Norfolk Southern mixing centers • Steel company train yard • U.S. Navy explosives storage site (rail, ship, cranes)

– rapid transit
• Miami Metrorail and Portland TRI-MET

– ports
• Port of Singapore
– ships, tractor/trailer and agv, yard cranes, quay cranes

Demonstration: A Rail Demo Model

Topics
• • • • The Challenge Example: Simulation Modeling in One Day What‟s in the AutoMod Toolkit? An Approach to Rapid Modeling for the „Paper Switching‟ Exercise • Discussion

The Challenge
• Rapid Model Development
– Model must be ready to run in days – Data should be standardized as much as possible

• Rapid Experimentation • Rapid Analysis • Other aspects outside the simulation toolkit
– data collection & preparation, ...

Example: Rapid Model Building
• Taco Bell template model
– model of auto traffic in parking lot, adjacent streets and drive-thru (0, 1 or 2) – Taco Bell has applied the model to 80+ sites – They develop a new model in one day
• import CAD drawing and develop new layout (“paths”) of adjacent streets and parking lot • enter site-specific data (traffic rates, …) in standardized format • NO programming • run and get standard reports (analysis may take a few days)

– Initial development took 6-8 weeks

Demonstration: The Taco Bell Template Model

What‟s a Template Model?
• Specific, narrow domain
– well-defined scope, boundary, level of detail

• Generic model
– everything is a “variable”, including the layout – completely data-driven

• Standardized input files • Standard output reports
– customized for the application (not standard AutoMod reports)

Is a Template Model Possible for the Paper Switching Application?
• Assumptions
– Man-machine simulator
• Needs to have an interactive front-end • Humans provide the hard decision-making “logic” • Model makes the basic moves, displays current state, tracks standard statistics, tracks history
• Model needs to replay and allow restart at given time

– Needs to run on a network
• multiple front-ends, multiple simultaneous users • multiple models (or multiple copies of same model)

What‟s in the AutoMod Toolkit?
• • • • MCM/MMS Generic modeling support Replay and Checkpoint/Restart Tracking History
– Presentation

• Other requirements
– standard inputs and outputs

The AutoMod Toolkit: MCM/MMS
• MCM
– Model Communications Module – Facilitates messaging between models and other applications, such as:
• Custom user interfaces written in Excel, VB or Java

• MMS (Multiple-Model Synchronization)
– Allows multiple AutoMod model to run together
• Simulation clocks automatically synchronized • Works on 1 PC or over network • MCM messaging to “send entities” or information model to model

MCM/MMS: Actual Applications
• MMS allows any number of AutoMod models to run together with synchronized clocks, and to pass messages
– USPS
• • • • 3 to 7 synchronized AutoMod models simultaneous model development easy swapping of one mh design for another experimentation with an integrated model

– AutoMod + AutoSched AP
• uses AutoMod to add mh and animation quickly without having to enhance the AutoSched product

MCM/MMS - Overview
Control system UI s/w
• Excel • VB and Java UI

AutoMod Models AutoSched Models Other simulation package

AutoMod Model

Demonstration: MCM/MMS In Action

What is MMS?
• Provides time management
– offers 2 modes: exact and periodic synchronization – models are event-driven and run as fast as possible, or with animation, run with a display step – repeatable

• Provides message passing
– automatic synchronization messages – model dependent messages
• message is any no. of integers, reals and strings • message usually represents an external event or data transfer • each model has a callback function to process external events

What is MMS?
• Works on 1 PC or any no. over a LAN
– Based on sockets, so works with Windows, Unix – On Windows LAN, MMS has low overhead

• Provides debugging support
– Ability to interact with all models while running – Repeatable: capability to repeat run for debugging by re-run all models, or only one model driven by a message file.

• Hardened, tested, used in large-scale industrial models
– Prototype in use for 3+ years

• MMS available now in commercial release

MMS Time Management:
Exact and Periodic Mode
• In exact mode, the simulation clocks are synchronized perfectly
– only 1 model runs at a time
• appears as if all are running simultaneously

– MMS server controls which model runs

• In periodic mode, all messages are sent when desired, but are received periodically, say every 10 simulated seconds
– between message updates, all models run simultaneously – potential for large run-time gain – downside is possible loss of accuracy
• suitable only for properly defined, loosely coupled submodels

– repeatable

MMS Applications
Interactive custom UI
• Excel • VB • Java UI

AutoMod Model

Ergonomics or Robotic Cell Model

AutoSched AP Model

MMS Controller

Applications: US Postal Service
• USPS Processing and Distribution Center
– currently 3 AutoMod models in the suite – soon to be 6+ models – individual models for:
• equipment (LPE, FPE, IBS) • MH (conveyor, agv) • Facility control (scheduling, routing, dispatch, …)

– multiple model developers, geographically distributed
• each model can run standalone for debugging, V/V and initial runs and analyses

Postal Model
Facility Control Model

Equipment Models Conveyor AGVS
letters

flats

parcels

Applications: Semi-Conductor
(Presented at ASI Symposium, June„99)

• Integrated Mfg and MH Models for large semi-conductor manufacturer • AutoSched AP and AutoMod Models • AP model does facility control, scheduling, routing, processing…
– has all the “intelligence”

• AutoMod model is simpler, MH only
– receives commands to move a lot from A to B – notifies AP model upon delivery

Applications: Ergonomics
• An ASI customer (a simulation consulting firm) connected an AutoMod model to ergonomics model produced by another s/w company

The AutoMod Toolkit: Variables
• For path-based models (incl rail), a standard classification system for components and “control points” allows a generic model to adapt to new layouts
– main track, leads, ladder, … – “control points” can be variable

1 or more leads

Any no. of parallel tracks

The AutoMod Toolkit: Variables
• Generic logic to address the basic moves
– – – – pull into track X drop N railcars pull forward past switch and back into track Y …

• Conclusion: One AutoMod model can work with a range of layouts

Replay and Checkpoint/Restart
• Human-made decisions transmitted from the UI to the model can be recorded
– Allows play back of a complete shift or day
• Gives you a built-in way to do a presentation

– Allows checkpoint/restart capability
• Restart and play back to a specified point • Pick up with interactive human decisions
– “we goofed, let‟s back up 1/2 hour and try again” – true back-up of time not feasible, but re-run is fast when animation is off

AutoMod‟s Train Template
• Provides some support for typical train modeling
– automatic detection of head of train passing a point – automatic detection of train clearing a point (such as a switch) – dynamic acceleration and deceleration rates – currently, it‟s prototype but has been used by AutoSimulations‟ consulting group numerous times

Requirements for a Custom Interactive Front-End
• Model must be driven by a custom UI
– Standardized, pre-written
• Will it require some customization on each project?

– Standard model controls
• • • • Pause/continue Animation on/off View control (zoom) Restart and re-run up to specified point

– Specific commands for train control – Displays system state and standardized output reports – Easy, quick to learn and use

Standardized Inputs and Reports
• How feasible to have standard inputs across the range of anticipated applications?
– – – – Train arrivals Train characteristics (no. & types of railcars) Speeds, acceleration, braking, delays ...

• Are there standard outputs?
– Can custom outputs be added quickly?

Standardized Set of Decisions
• The logic behind the decisions is provided by the human users
– makes model simpler – makes a generic model possible

• But can the actual decisions (or commands) be standardized?
– Pull into track X (one of several parallel tracks) – Stop with engine at point Y, or Stop with last car at point Z – Drop last N railcars

Limitations
• Model would move trains, drop off and pickup railcars
– Animation would display trains and railcars only

• Other activities would be represented by time delays and would not be shown visually
– automobiles unload and re-load (mixing center) – container movement, unload and load

Summary: An Approach to Rapid Modeling for „Paper Switching‟
• Same model running on multiple machines
– – – – synchronized in simulation time runs real time, faster or slower color-coded animation shows current state allows different users to view different parts of yard and different reports

• Standard interactive UI with model control and reporting

Discussion: Q & A
• Is it feasible? Is it cost effective? • Can the movement logic be modeled in a generic fashion?
– The “hard” logic comes from human participants – The model responds to commands

• Other modeling activities - data collection, analysis, etc - must still take place.
RASIG
Rail Applications Special Interest Group


								
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