1. System Optimization - I Multi-disciplinary Design Optimization
K Sudhakar PM Mujumdar
Centre for Aerospace Systems Design & Engineering
Indian Institute of Technology, Mumbai

2. 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

3. System Analysis
Inputs
Outputs
Analysis

4. Many designs may satisfy requirements.
System Analysis
Design Variables
Requirements
Analysis
Many designs may satisfy requirements.
Goodness criteria?

5. System Analysis Objective Analysis Design Variables Requirements as
Constraints
Objective
Analysis

6. System Design Objective Analysis Design Variables Change design
Subjective?
Design Variables
Requirements as
constraints
Objective
Analysis

7. System Analysis
Geometry,
Etc.
Performance,
Cost,
Weight,
Analysis

8. System Analysis Performance, Geomtery, Cost, Etc. Weight,
Structures
Controls
Aerodynamics
Propulsion
Trajectory
Identify, validate and integrate modules

9. Sub-System Analysis
Aerodynamics
Aerodynamics

10. Sub-System Analysis Aerodynamics Analysis - Recursion CFD for drag
VLM for Lift
CFD for drag
Aerodynamics
Analysis - Recursion

11. Sub-System Analysis Aerodynamics
DATCOM
CFD
Aerodynamics
Fidelity level of analysis - Low, Medium, High

12. 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

13. System Designer’s Nightmare!
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!

14. Frameworks for Integration
Distributed analyses & ownership
System level virtual integration
System level vocabulary
Customized standard tools
eg. iSIGHT, Phoenix,
& CASDE Framework
HW-1
Aerod
HW-2
Struct
HW-4
Prop
HW-6
Controls
HW-5
System-I
HW-3
System-II
HW-7
Optimizers

15. System Analysis XS = {x1, x2, x3} YS = { y1, y2, y3 } A1 A2 XS YS A3

16. System Analysis How to execute A1? XS = {x1, x2, x3}
X1, Y2 A1 ? Y1 X2 A2 Y2
XS = {x1, x2, x3}
YS = { y1, y2, y3, x1 } X3 Y3 A3
How to execute A1?

17. System Analysis - Prescribed Scheduling
YS = { y1, y2, y3 } x1 x2 x3

18. System Analysis A2 A1 y1 y2 A3 y3
YS = { y1, y2, y3 } x2 x3 x1

19. 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

20. ? Problem statement Modeling & Simulation environment
Integrating models
Sensitivity analysis (derivatives)
Optimization technology
etc.