Lecture Notes Set 2 - Designing Mechatronic Systems

MFE 3102

Design Design of Mechatronic Mechatronic Systems Systems

Mechatro Mechatronic nic System System Design Design Dr Conrad Pace

MFE3102 Design Design of Mechatronic Systems C. Pace

Page 2.1

The Design Process for Mechatronic Systems – The Integration Aspect within the Design Process System Definition Integrated engineering

Requirements Engineering Specification System General Design

Domain specific engineering

Mechanical and electrical engineering

Electronic engineering

Information and control engineering

Operating engineering

Process Design (Part that performs work)

Electronic hardware design

Information processing and software design

Human machine interface (HMI) design

Integration of components (hardware) Integrated engineering

Integration of information processing (software)

System Integration (hardware and software) System testing

Integrated Mechanical and electronic system

Manufacturing Mechatronic System MFE3102 Design Design of Mechatronic Systems Mechatronic C. Pace

Page 2.2

The Design Process for Mechatronic Systems • Requirements Engineering Specification  – Definition of the general functions  – Definition of general constraints • Reliability and safety requirements • Development and manufacturing requirements

 – Partitioning into manageable modules • Specification of the Modules  – Functions  – Performance  – Constraints and limitations

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.3

The Design Process for Mechatronic Systems – Defining System Requirements System Requirements

OPERATIONAL

FUNCTIONAL

Define major system  purpose – why is the system required.

NON-FUNCTIONAL

Specify what the system has to do

Bounding

Define constraints and influences on system functions

Defining

Define System interaction Define System internal actions with environment at system boundary 

Performance How a particular function must be performed  MFE3102 Design of Mechatronic Systems C. Pace

System Constraints on whole system

Implementation How should the system be built 

Page 2.4

The Design Process for Mechatronic Systems • System Design  – Detailed Analysis and Design of partitioned system • Mechanical, hydraulic, pneumatic, electrical, etc.. • Sensors and actuators • Automatic control and information processing • Interfacing with human operator=

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.5

The Design Process for Mechatronic Systems • System Design  – Task distribution between mechanical and electrical/ electronic/ software design • Simplification of mechanical/ electrical design • Replacement of simple linearised mechanical/ electrical systems with non-linear software based control

 – Realisation of Functions • Power Conveyance (Energy Transfer Component of System) • Information Processing (Information Component of System) • Domain Interfaces (Sensors and Actuators) • Realisation of Synergies (possible integration effects)

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.6

The Design Process for Mechatronic Systems • Component Design  – Modelling and Simulation - Analysis of individual component behaviour  • Dynamic Requirements for components • Performance measures for software based control

 – Development of components • Mechanical Design • Electronic Design • Control Design • Software Design

 – Component Testing • Testing performance of components • Component interface testing MFE3102 Design of Mechatronic Systems C. Pace

Page 2.7

The Design Process for Mechatronic Systems • System Integration  – Hardware Integration • Spatial integration of components • Signal interfacing • Creation of Synergetic Effects  – Interface influences amongst components

 – Software Integration • Integration of software functions with hardware components

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.8

The Design Process for Mechatronic Systems • System Testing  – Testing of all functions of components  – Testing of integrated system  – Verification – testing that the product meets its specifications  – Validation – field testing (testing if the final product is appropriate for its purpose with regard to the requirements)

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.9

A ‘V’ Development Scheme for Mechatronic Systems Degree of maturity Production

Validation

Requirements

Field Testing

Verification

Specifications

System Testing

System Design System Design

Modelling and Simulation

Component design (domain specific)

Prototypes

System Integration (software)

System Integration

System Integration (hardware) Component testing

Mechatronics Components MFE3102 Design of Mechatronic Systems C. Pace

Page 2.10

A Common System Specification A Communication Problem between areas of Specialisation – the need for a common specification •

the design of the mechanical elements of the system is primarily concerned with spatial relationships and interactions

•

the design of the electronic component of the system is primarily concerned with signal processing and the interconnection of discrete components and devices

•

the design and engineering of the associated software is primarily concerned with the development of data and information processing algorithms. MFE3102 Design of Mechatronic Systems C. Pace

? Page 2.11

A Common System Specification • System Representational Models  – Models that are not technology specific and that allow the specification of general system characteristics  – The representation allows a proper System breakdown which allows focused analysis on the individual system components.  – Typical Examples • Information and Dataflow Diagrams • Power and Energy Flow Diagrams • State and Transition Diagrams • Sequence Diagrams • Morphological Charts • Function Means Tree • Hierarchical Diagram Constructs • Timing Diagrams

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.12

A Common System Specification • Information and Dataflow Models  – Model flow of information and data through the system  – Originated from Software systems engineering. However can be extended to multi-domain systems  – Allow appropriate division of systems into subsystems, aiding analysis management Process B

Process D

Dataflow 2

Dataflow 1 Process  A Process C

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.13

A Common System Specification • Power and Energy Flow Models  – Bond graph models – model the flow of energy and power   – Energy and power are parameters that are domain independent  – Not used for modelling information flow Sf:i

1

R:r1

MFE3102 Design of Mechatronic Systems C. Pace

Gy:x x= 1/k

1

R:d

I:M

Page 2.14

A Common System Specification • State Transition Diagrams  – Model individual system states and conditions pertaining to the specified states  – Model the transition conditions between states

Transition Condition AB

State A

State B Transition Condition BC

Transition Condition CB

State C

Transition Condition AC

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.15

A Common System Specification • Sequence Diagrams  – Model the order of a sequence of operations and associated action transition logic  Action A Transition 1  Action B Transition 2

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.16

A Common System Specification • Morphological Charts  – Spatial Modelling of potential solutions of system elements  – Provides a qualitative means of evaluating element spatial integration

• Function-Means Trees  – Breaks down complex operations into basic functions that constitute operation  – Can illustrate individual functional requirements and related solutions

• Hierarchical Diagram Constructs  – Techniques that provide a means of modelling individual operations at various operational levels with appropriate links and relations being defined MFE3102 Design of Mechatronic Systems C. Pace

Page 2.17

A Common System Specification • Timing Diagrams  – Modelling of timing constraints of sequential/ transition operations  – Used to investigate relationships amongst time dependent operations. P2

P1

P3 t1

MFE3102 Design of Mechatronic Systems C. Pace

t2

Page 2.18

A Common System Specification – An Example Suppose we want to design an intelligent washing machine. Such a washing machine should satisfy the following requirements; • A standard size • Can take a standard wash load • Should determine the load make-up • Should identify the fabric type • Should determine the best wash cycle given the load make-up and fabric • Should detect mixed loads • Inform the user of any decisions taken on the wash cycle selected • Cost within 15% of the existing machine prices • Should have a distinctive style • Should use domestic water and currently available detergents • Should work with a standard electric supply • Should operate at appropriate temperatures and wash cycles • The user can check the wash cycle and override the machine decision • Should rinse and spin-dry the clothing as appropriate to the load and type. MFE3102 Design of Mechatronic Systems C. Pace

Page 2.19

Analysing System Functionality • A Structured Analysis Approach  – Objectives • Sufficiently abstract to capture both physical and information characteristics • Include human and non-technical forms of interaction • Presenting information in a clear and simply fashion

 – Use of Representational Diagrams  – Information Hiding  – Abstraction

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.20

Analysing System Functionality • Structured Analysis Dataflow Diagram (DFD) Depicts system activities/ processes and interactions   Dataflow   Process   Terminator   Datafile • • • •

Terminator 

Datafile

Dataflow Process

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.21

Analysing System Functionality • Structured Analysis Data DataDictionary Dictionary(DD) (DD)

Defines Definesdataflows dataflowsininDFD’s DFD’s IS EQUIVALENT IS EQUIVALENTTO TO  AND  AND EITHER-OR EITHER-OR ITERATIONS ITERATIONSOF OF OPTIONAL OPTIONAL • •

• • • • • • • •

Process ProcessSpecification Specification(PS) (PS)

Specifies Specifiesprimitive primitiveprocesses processesininthe thelowest lowestlevel level DFD’s DFD’s

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.22

Structured Analysis Term. A

Top Level – Context Diagram Definition of system operation

Term. B System Operation

Level 0 Diagram Breakdown of Context Diagram single Process

Proc. 1

Level 1 Diagram Breakdown of Level 0 processes (ex. Proc. 1)

Proc. 1.1

Proc. 2

Proc. 3

Proc. 1.2

Proc. 1.3

Proc. 1.4

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.23

Structured Analysis DATAFLOW DIAGRAM

PROCESS SPECIFICATION

P

P …………….……… ………………………

Dataflow

Datafile

….

DATA DICTIONARY

Datafile ……………. ……………………… Dataflow ……………

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.24

Washing Machine Example CONTEXT DIAGRAM Installers

Domestic Services

INSTALLATION_SERVICE SERVICES

WASTE

MACHINE_OUTPUTS

Wash Clothes Intelligently MAINTENANCE_SERVICE

User

USER_INPUTS

Service Providers

FAULT_CODES

SERVICE_REQUEST

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.25

Washing Machine Example LEVEL 0 DIAGRAM DIAGRAM 0 – Wash Clothes Intelligently SERVICES INSTALLATION_SERVICE

MAINTENANCE_SERVICE

Install Washing Machine 1

Maintain Washing Machine 3

Use Washing Machine 2 MACHINE_OUTPUTS

MFE3102 Design of Mechatronic Systems USER_INPUTS C. Pace

FAULT_CODES

WASTE

Page 2.26

Washing Machine Example LEVEL 1 DIAGRAM

DETERGENT_CONDITIONER

DIAGRAM 2 – Use Washing Machine LOADED_CLOTHES

MAINS_POWER

Load Dirty Clothes 2.1

WATER_SUPPLIES

Determine Load 2.2

Wash Clothes 2.4

MAINS_POWER DIRTY_CLOTHES

WASTE_WATER

W_C_FAULT LOAD_MAKE_UP

WASHED_CLOTHES D_L_FAULT

Determine Best Wash Cycle 2.3

SELECTED_WASH_CYCLE

Unload Clean Clothes 2.6

BEST_WASH_CYCLE

D_B_W_C_FAULT

USER_INFORMATION

USER_COMMANDS

MFE3102 Design of Mechatronic Systems C. Pace

Communicate with User 2.5

MAINS_POWER

CLEAN_CLOTHES

FAULT_CODES

Page 2.27

References • Mechatronics Handbook , Robert H. Bishop (Ed.) , CRC Press, 2002 • Mechatronics Systems Design with Applications, Course book, Kevin C. Craig, Fred P. Stolfi, the American Society of Mechanical Engineers (ASME), the Institute of Electrical and Electronic Engineers, USA (IEEE), 1993 • Mechatronics, Dan Necsulescu, Prentice Hall, 2002

MFE3102 Design of Mechatronic Systems C. Pace

Page 2.28