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System Optimization - IMulti-disciplinary Design Optimization
K Sudhakar PM Mujumdar
Centre for Aerospace Systems Design & Engineering
Indian Institute of Technology, Mumbai
Formal Process for Design
• Requirements Capture Problem statement User, Regulatory, Implied, . .
• Establish Concepts
• Identify Modeling & Simulation Environment for System Analysis. Easy for familiar concepts.
• Design Space Exploration for chosen concepts. Subjective, Parametric studies, Optimization, ?
• Design Specification
System Analysis
Inputs OutputsAnalysis
System Analysis
Design Variables RequirementsAnalysis
Many designs may satisfy requirements.Goodness criteria?
System Analysis
Design Variables
Requirements asConstraints
Objective
Analysis
System Design
Change designSubjective?
Design Variables
Requirements as constraints
Objective
Analysis
System Analysis
Geometry,Etc.
Performance,Cost, Weight,
Analysis
System Analysis
Geomtery,Etc.
Performance,Cost, Weight,
Structures
Controls
Aerodynamics
Propulsion
Trajectory
Identify, validate and integrate modules
Sub-System Analysis
Aerodynamics
Aerodynamics
Sub-System Analysis
VLM for Lift
CFD for drag
Aerodynamics
Analysis - Recursion
Sub-System Analysis
DATCOM
CFD
Aerodynamics
Fidelity level of analysis - Low, Medium, High
System Modeling & Simulation
• Requires great insight• Need to use most appropriate model• Occam’s razor• Integration of sub-system models• Issues in integration
– Technical
– Human
• . . . . .
Why do you want my program?
I have a new version of analysis software
You have to know my code to be able to execute it!
System Designer’s Nightmare!
I cannot find the correct tuning parameters!
Integration Issues
Frameworks for Integration
• Distributed analyses & ownership• System level virtual integration• System level vocabulary• Customized standard tools• eg. iSIGHT, Phoenix, • & CASDE Framework
HW-1Aerod
HW-2Struct
HW-4Prop
HW-6Controls
HW-5System-I
HW-3System-II
HW-7Optimizers
System Analysis
XS = {x1, x2, x3} YS = { y1, y2, y3 }
A1
A2
X2
X1, Y2 Y1
Y2
XS YS
A3
X3Y3
System Analysis
A2
X2
Y1A1
?
X1, Y2
Y2
A3
X3Y3
XS = {x1, x2, x3} YS = { y1, y2, y3, x1 }
How to execute A1?
System Analysis - Prescribed Scheduling
A1
A2
y2
Y1
A3
Y3
YS = { y1, y2, y3 }
x1
x2
x3
y2
System Analysis
A2
A1
y1
y2
A3
y3
YS = { y1, y2, y3 }
x2
x3
y2
x1
How to explore design space?
• Brute force? How many function evaluations?• Evolutionary methods, derivative free - GA, SA!• How to compute derivatives?
– Time intensive models
– noisy models
Surrogate models - DOE/RSM, DACE
Variable Fidelity Methods
Sensitivity Analysis
Problem statement
Modeling & Simulation environment
Integrating models
Sensitivity analysis (derivatives)
Optimization technology
etc.
?