Transcript MDO – Past, Present & Future

System Optimization - I
Multi-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
Analysis
Inputs
Outputs
System Analysis
Design Variables
Analysis
Requirements
Many designs may satisfy requirements.
Goodness criteria?
System Analysis
Objective
Design Variables
Analysis
Requirements as
Constraints
System Design
Objective
Design Variables
Analysis
Requirements as
constraints
Change design
Subjective?
System Analysis
Analysis
Geometry,
Etc.
Performance,
Cost,
Weight,
System Analysis
Aerodynamics
Structures
Geomtery,
Etc.
Controls
Trajectory
Performance,
Cost,
Weight,
Propulsion
Identify, validate and integrate modules
Sub-System Analysis
Aerodynamics
Aerodynamics
Sub-System Analysis
VLM for Lift
Aerodynamics
CFD for drag
Analysis - Recursion
Sub-System Analysis
DATCOM
Aerodynamics
CFD
Fidelity level of analysis - Low, Medium, High
System Modeling & Simulation
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Requires great insight
Need to use most appropriate model
Occam’s razor
Integration of sub-system models
Issues in integration
– Technical
– Human
• .....
Integration Issues
I cannot find the correct tuning
parameters!
Why do you want my
program?
System Designer’s Nightmare!
I have a new version of
analysis software
You have to know my code to be
able to execute it!
Frameworks for Integration
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Distributed analyses & ownership
System level virtual integration
System level vocabulary
Customized standard tools
eg. iSIGHT, Phoenix,
& CASDE Framework
HW-6
Controls
HW-7
Optimizers
HW-3
System-II
HW-1
Aerod
HW-2
Struct
HW-4
Prop
HW-5
System-I
System Analysis
X1, Y2
A1
Y1
X2
XS
Y2
A2
YS
Y3
X3
A3
XS = {x1, x2, x3}
YS = { y1, y2, y3 }
System Analysis
X1, Y2
A1
Y1
?
X2
Y2
A2
XS = {x1, x2, x3}
YS = { y1, y2, y3, x1 }
Y3
X3
A3
How to execute A1?
System Analysis - Prescribed Scheduling
x1
x2
x3
A1
y2
Y1
A2
y2
A3
Y3
YS = { y1, y2, y3 }
System Analysis
x2
x1
x3
A2
y2
y2
A1
y1
A3
y3
YS = { y1, y2, y3 }
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.