2.design mecatrónica
TRANSCRIPT
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1540 Introduction To Mechatronics 1Stefan Williams
Introduction to Mechatronics
Mech-1540
Stefan B. Williams
Research Fellow of Mechatronic Engineering
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1540 Introduction To Mechatronics 2Stefan Williams
Schedule of Events
Q 2 of Assign 2MID SEMESTER BREAK
Spare19/614
Due 13/6Major Assignment12/613
Case Study : Unmanned Air/Land/Sea Vehicles5/612
Case Study : Formula SAE29/511
Active Sensor Systems (Graham Brooker)22/510
Due 16/5Assignment 2 - Control and Modelling15/59
Q 4 of Assign 2System Modelling and Control8/58
Q 3 of Assign 2Computer Software and Design Tools1/57
6
5
4
3
2
1
Week
17/4
10/4
3/4
27/3
20/3
13/3
Date
Computer Hardware
Assignment 1 Design Exercise
Sensors
Actuators
Design Process
Introduction
Content
Q 1 of Assign 2Due 11/4
Q 3 of Assign 1
Q 2 of Assign 1
Q 1 of Assign. 1
Assignment Notes
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What is Engineering Design?
Engineering Design is the systematic,
intelligent generation and evaluation of
specifications for products whose form and
function achieve stated objectives and satisfyspecified constraints
The purpose of design is to derive from a set
of specifications a description of a product
sufficient for its realization
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1540 Introduction To Mechatronics 4Stefan Williams
Why is Engineering Design important?
It provides us with
A methodology to be followed in the search for a
solution to a recognized problem
A set of requirements that characterize asuccessful solution to the problem
A means of managing increasingly complex,
technological problems by breaking the task of
finding a solution into smaller sub-system design
problems
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1540 Introduction To Mechatronics 5Stefan Williams
The Design Process
Problem Identification Systems Design
System Specification
Systems Modelling
Implementation Component Selection
Component Testing
System Integration
System Verification Iteration
Operation and Maintenance
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The Product lifecycle
Concept
Exploration
System
Definition Engineering
Development
System
Qualification
Deployment
Operation &
Maintenance
Production
Disposal
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1540 Introduction To Mechatronics 7Stefan Williams
Design models : The Waterfall
Requirements
Design
Implementation
Testing
Integration
Operation and
Maintenance
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1540 Introduction To Mechatronics 8Stefan Williams
Design models : The Spiral
Determine goals,alternatives,
constraints
Evaluatealternatives and
risks
Develop
and testPlan
Implementation Plan
Integration & Test Plan
Development Plan
Requirements,
lifecycle PlanConcept of
operation
Acceptance test
Validated design
Validated reqts
Detailed
Design
Initial
design
Reqts
Risk analysis
Risk analysis
Risk analysis
Risk analysis
Problem
Identification
Alternatives,
constraints
Alternatives,
constraints
Alternatives,
constraints
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1540 Introduction To Mechatronics 9Stefan Williams
Design
Implement
Integrate
Design
Implement
IntegrateDesign
Implement
IntegrateDesign
Implement
IntegrateFirst Sub-system Tier
System
Integration
Contract Boundary
Verification
Design
Implement
Integrate
Tier n
Concept
Definition
System
Design
Operational
Evaluation
Design Models: The System V
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1540 Introduction To Mechatronics 10Stefan Williams
The Design Process
Problem Identification Systems Design
System Specification
Systems Modelling
Implementation Component Selection
Component Testing
System Integration
System Verification Iteration
Operation and Maintenance
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1540 Introduction To Mechatronics 11Stefan Williams
Problem Identification
Identify problem to be solved
talk to the customer
acquire domain knowledge
expertise to be brought to bear Clarify the problem domain
identify the problem boundaries
develop design parameters that allow comparative
judgement of competing designs
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1540 Introduction To Mechatronics 12Stefan Williams
Problem Identification
Understanding
operational concept
system context
major states and modes of the system identify other unstated needs
Discussion of potential solutions
proposal of various solution concepts
brain storming
lateral thinking
interaction with customer
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1540 Introduction To Mechatronics 13Stefan Williams
Problem Identification
Design constraints must be identified Restrictions or limitations on a behaviour or a
value or some other aspect of a designed objectsperformance
Requirement analysis allows us to verify that we have reached a solution
a description of the requirements that characterisea solution
the criteria to be used to verify that therequirements have been met
produces an understanding of the nature andscope of the remaining activities
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Sources of Requirements
Customer Requirements
Contract documents and standards
Operational Concept Descriptions (OCD) etc.
Derived Requirements To correct ambiguity or incomplete requirements
Implied or transformed from higher-level
requirements
Allocated Requirements Divided or allocated to multiple lower level
requirements
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1540 Introduction To Mechatronics 15Stefan Williams
Planning and Project Management
Managementis the process of achievingorganizational goals by engaging in the fourmajor goals of planning, organizing, leadingand controlling
Involves planning major and minormilestones of design process
Time line and allocation of availableresources to complete the job
Project scope, spending and schedule mustbe estimated and tracked during theremainder of the design process
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Time Lines
ID Task Name Start End Duration
Mar 2003 Apr 2003 May 2003
3/16 3/23 3/30 4/6 4/13 4/20 4/27 5/4 5/11 5/18 5/25
1
2
5
6
7
8
9
5d21/03/200317/03/2003Problem Identification
20d17/04/200321/03/2003Systems Dessign
20d15/05/200318/04/2003Implementation
5d24/04/200318/04/2003Component Selection
15d15/05/200325/04/2003Component Testing
10d29/05/200316/05/2003System Integration
5d5/06/200330/05/2003System Verification
4
3 10d3/04/200321/03/2003System Specification
15d17/04/200328/03/2003System Modelling
Jun 2003
6/1 6 /8 6/15 6 /22
An example of a Gantt Chart a graphical representation of the time line and
interrelationship between tasks
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1540 Introduction To Mechatronics 17Stefan Williams
The Design Process
Problem Identification Systems Design
System Specification
Systems Modelling
Implementation Component Selection
Component Testing
System Integration
System Verification Iteration
Operation and Maintenance
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Characteristics of a System
A complex set of interrelated elements
working together to fulfill some designated
need
must be functional and able to respond to thatneed
Sub-systems can be equipment, materials,
software, people, and other systems
A system is contained within some form ofhierarchy
Sub-systems are not necessarily technology-
based
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1540 Introduction To Mechatronics 19Stefan Williams
Systems Engineering
The design of the whole as distinct from the design
of the parts
A structured way of handling complexity
Defines the interfaces between major components of
the system
The best way to maximise probability of a successful
outcome
But it is not.
A silver bullet
A cookbook approach to success
An excuse to stop thinking
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1540 Introduction To Mechatronics 20Stefan Williams
Why do we Need Systems Engineering ?
Simplification of Complex Systems
Control Design Process
Flow down of System Requirements to
Component Level Facilitate Progressive Testing (flow up)
Production and cost approximately 90% ofthe cost of production determined during
design phase ENSURE FINAL PRODUCT MEETS
REQUIREMENTS
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1540 Introduction To Mechatronics 21Stefan Williams
The Systems Engineering as
Front End
System
Design
Design
Implement
Integrate
Design
Implement
IntegrateDesign
Implement
IntegrateDesign
Implement
Integrate
System
Integration
Concept
Definition
Operational
Evaluation
Tier 0
Tier 1
Tier 2
Inte
gratio
n
Decompositio
n
TheFrontEnd
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1540 Introduction To Mechatronics 22Stefan Williams
System Specifications
Specifications are precise descriptions of the
properties of the object being designed
Design specifications articulate in a numerical or
measurable way what a design is supposed to do and
provide the basis for evaluating that designPrescript ive specif icat ions specify values of attributes that
designed object must meet to be successful
Procedural specif ications identify procedures or methods
to be used in calculating attributes
Performance specif icat ions characterise the desired
behaviour or performance of the system
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1540 Introduction To Mechatronics 23Stefan Williams
Interface Specifications
Specifications are also required for the
internal components of the system
The interface between components must be
specified to enable the problem to be brokenup into manageable sub problems
Interface specifications should be formalized
in sufficient detail to minimize ambiguity and
the need to reformulate interfaces in thefuture
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1540 Introduction To Mechatronics 24Stefan Williams
Modular Design
Desirable attributes of modular system
components,
Low Coupling
High Cohesion Well defined interfaces between components
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Modular Design
Definition,
Coupling - a measure of the relative
interdependence between subsystems.
Simple connectivity among subsystems results in a
system that is easier to understand and less prone to aripple effect when errors or changes occur in another
part of the system.
Cohesion - a measure of the relative functional
strength of a subsystem. A cohesive subsystem performs a task with littleinteraction with other parts of the system.
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1540 Introduction To Mechatronics 26Stefan Williams
Modular Design
In summary, develop subsystems with,
single-minded function.
an aversion to excessive interaction with other
subsystems.
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1540 Introduction To Mechatronics 27Stefan Williams
Systems Modelling
Modelling of
overall response of the system
individual components of the system
Models allow us to predict the systembehaviour
Will it meet our design constraints?
Will the system be stable?
What components are required for the system?
What are the characteristics of those components?
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1540 Introduction To Mechatronics 28Stefan Williams
The Design Process
Problem Identification Systems Design
System Specification
Systems Modelling
Implementation Component Selection
Component Testing
System Integration
System Verification Iteration
Operation and Maintenance
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1540 Introduction To Mechatronics 29Stefan Williams
Component Selection
Selection of appropriate components to meet
design constraints and fulfil system design
Identification of commercial off-the-shelf
(COTS) and specialised components Verification that components meet the
models formulated during systems design
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1540 Introduction To Mechatronics 30Stefan Williams
l The design of a Component is not affected by the
size or complexity of the System it is used in.
l The design of a component is driven by three
requirements:
l Form
l Fit
l Function
Design of Components
Physical
-Size
-Shape
-Weight
-CG
-Inertia
Interfacing
-Mechanical Interfacing (fixing)
-Electrical Interfacing
-Communication / Data Interfacing- Effect of function
What it does &
How it does it
-Performance
-Environment
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1540 Introduction To Mechatronics 31Stefan Williams
Exercise - Design of Components
Consider 2 components from vastly different systems:
System 1. An electronic automatic garage door.
Component: Actuator to open and close the door.
System 2. A Ship Based Theatre Air Defence System
Component: Actuator to move the missile control fins
Q1. What information is required to design or select an
appropriate actuator for each case?
Q2. How do you determine that information?
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1540 Introduction To Mechatronics 32Stefan Williams
The Design Process
Problem Identification Systems Design
System Specification
Systems Modelling
Implementation Component Selection
Component Testing
System Integration
System Verification Iteration
Operation and Maintenance
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Requirements
Analysis
Functional Analysis/
Allocation
Synthesis
Requirements
Analysis
Functional Analysis/
Allocation
Synthesis
RequirementsAnalysis
Functional Analysis/Allocation
Synthesis
Requirements
Analysis
Functional Analysis/
Allocation
Synthesis
Component Implementation
Requirements
Analysis
Functional Analysis/
Allocation
Synthesis
RequirementsAnalysis
Functional Analysis/
Allocation
Synthesis
RequirementsAnalysis
Functional Analysis/Allocation
Synthesis
Unit
Verification
Sub-system
Verification
System
Verification
Integrate Correct
Integrate Correct
Integrate Correct
Verification
Criteria
Verification
Criteria
Verification
Criteria
Design
Im
ple
ment
The Implementation Leg
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1540 Introduction To Mechatronics 34Stefan Williams
System Integration
Integration of the individual components toform the system
Verification of individual sub systems
typically undertaken during this stage Do the system components meet the
specifications?
Do the interface specifications accurately
capture the final system configuration?
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1540 Introduction To Mechatronics 35Stefan Williams
Definitions
Integration: The merger or combining of two or morelower level elements into a functioning or unifiedhigher level element with the logical and physicalinterfaces satisfied.
Verification: Confirmation by examination andprovision of objective evidence that the specifiedrequirements to which an end product is built, codedor assembled have been fulfilled.
Validation: Confirmation by examination and
provision of objective evidence that the specifiedintended use of an end product or aggregation of endproducts is accomplished in an intended usageenvironment.
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1540 Introduction To Mechatronics 36Stefan Williams
Design for Integration
Multiple levels of integration and verification
Each level corresponds to the design
hierarchy
The interfaces between all components mustbe defined
The interfaces between the system and
external systems must be defined
Engineering models and prototypes can
assist the design and implementation
process
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1540 Introduction To Mechatronics 37Stefan Williams
The Design Process
Problem Identification
Systems Design
System Specification
Systems Modelling
Implementation Component Selection
Component Testing
System Integration
System Verification
Iteration
Operation and Maintenance
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1540 Introduction To Mechatronics 38Stefan Williams
System Verification
Verification of the system performance
Does the system meet our requirements?
If the system or some component of the
system does not meet the specification, whynot? Can it be rectified?
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1540 Introduction To Mechatronics 40Stefan Williams
Integration and Verification
Problems
Plans must cover what to do if integrationproblems or verification failures occur
Corrected at the next level down or design
where necessary Dealing with COTS
Undocumented features
Not developed for the environment
Defined behaviour and interfaces
Support
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1540 Introduction To Mechatronics 41Stefan Williams
The Design Process
Problem Identification
Systems Design
System Specification
Systems Modelling
Implementation
Component Selection
Component Testing
System Integration
System Verification
Iteration
Operation and Maintenance
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Iteration
For any subsystems that do not meet thedesign requirements, some iteration may be
required
Iteration can occur at any stage in the design the earlier the better
Changes to design will have a cascading
effect on remainder of system design
Proper and thorough systems design should
minimize the need for change
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1540 Introduction To Mechatronics 43Stefan Williams
The Design Process
Problem Identification
Systems Design
System Specification
Systems Modelling
Implementation
Component Selection
Component Testing
System Integration
System Verification
Iteration
Operation and Maintenance
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Installation and Validation
Installation into the operational environment
Interfaces to external systems may require
simulation
Uncontrolled environment - validate inphases
May involve user training
Validation of user manuals
May be used to verify operational
requirements such as availability
Must be well planned
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Operation and Maintenance
Once the design has been validated, theproduct must be produced, sold and
maintained
A good design should lead to a product thatis easy to operate and maintain