Value Driven Design Logo

7.12 - System Simulation

Overview

Simulation is a problem solving technique in which a detailed model of a process or system is built and used to predict the behaviour of the real world system or design when affected by either internal or external changes.

Principal Uses of Simulation in Manufacturing

Design Tool

Decision Aid

Training Aid

In computer simulation a spread sheet package, a computer program using high level languages or a simulation package is used to represent the system under consideration. It is very useful when dealing with complex systems and enables the prediction of short, medium and long term behaviour of the system being modelled.

Some systems diagramming tools also have simulation capability.

CAD systems are examples of product simulation. They can also be used to simulate certain manufacturing situations such as clash detection when using automatic assembly systems.

In manual simulation the system is represented by a desk top model and is manipulated by hand to simulate its behaviour. Significant data is logged, allowing further analysis. It is of particular use when sufficient understanding of the real-world problem is not available. It is a particularly useful tool for training operating staff because it gives hands-on experience.

Manual models can also be used for executive training ‘games’ such as scheduling or demand management that help managers understand the pros and cons of different methods.

A popular child’s building brick toy has been used to great success for manual modelling and ‘games’.

Criteria for Selection

Factor

Manual Simulation

Spreadsheet Package

Specific Program

Simulation Package

Development Cost

Low

Low

High

Medium

Development Time

Short

Short

Long

Medium

Model Size

Small

Medium

Large

Large

Speed of Running

Very Slow

Slow

Fast

Fast

Ease of Understanding

Very Good

Poor

Good

Very Good

Dynamic Access

Limited

Limited

Yes

Yes

Structured Modelling

Yes

No

Possible

Yes

Programming

No

Limited

Yes

No

Graphical

No

No

Possible

Yes

Use as a Training Aid

High

Medium

Med/Low

Med/Low

Simulation in Business Redesign

Iterations in Simulation

Criteria for Good Simulation Modelling

  • Simple to understand
  • Clear objectives
  • Flexible
  • Coherent and complete
  • Easy to maintain

Reasons for Simulation

  • Allows the testing of proposed designs before investing
  • Allows the evaluation of options without disturbing the real system
  • Quick and cheap evaluation of proposed changes in operation
  • Increases knowledge of systems behaviour

Notes:

“The most incomprehensible thing about the universe is that it is comprehensible” – Albert Einstein

 
Further Reading