Tools for Rapid Simulation Modeling for the ‘Paper Switching’ Application

Presented for RASIG

by

John Carson

AutoSimulationsRail ApplicationsSpecial Interest Group

RASIG

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

AutoMod Model

Control systemUI s/w

• Excel• VB and Java UI

AutoMod ModelsAutoSched ModelsOther simulation package

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

Ergonomics orRobotic Cell Model

AutoMod Model

MMS Controller

Interactive custom UI• Excel• VB• Java UI

AutoSched AP Model

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

letters

parcels

flats

Conveyor

AG

VS

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.

Rail ApplicationsSpecial Interest Group

RASIG