Introduction to Geometric Programming Based Aircraft...

105
Introduction to Geometric Programming Based Aircraft Design Warren Hoburg University of California, Berkeley Electrical Engineering and Computer Science Department 8 th Research Consortium for Multidisciplinary System Design Workshop July 16, 2013

Transcript of Introduction to Geometric Programming Based Aircraft...

Page 1: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Introduction to Geometric Programming Based AircraftDesign

Warren Hoburg

University of California, BerkeleyElectrical Engineering and Computer Science Department

8th Research Consortium for Multidisciplinary System Design Workshop

July 16, 2013

Page 2: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

[Adapted from Alonso 2012]

Challenge #1: Coupled Models

Challenge #2: Competing Objectives

Challenge #3: Solution Quality

Page 3: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

[Adapted from Alonso 2012]

Challenge #1: Coupled Models

[Kroo 1994]

I Significant disciplinary separation

I Expensive function evaluations

Challenge #2: Competing Objectives

Challenge #3: Solution Quality

Page 4: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

[Adapted from Alonso 2012]

Challenge #1: Coupled Models

Challenge #2: Competing Objectives

minimize

w1mfuel +w2

Vmax

+w3

mpay

mpay

Vmax

fuel fl

ow

rate

Challenge #3: Solution Quality

Page 5: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

Changespecifications

[Adapted from Alonso 2012]

Challenge #1: Coupled Models

Challenge #2: Competing Objectives

minimize

w1mfuel +w2

Vmax

+w3

mpay

mpay

Vmax

fuel fl

ow

rate

Challenge #3: Solution Quality

Page 6: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

Changespecifications

[Adapted from Alonso 2012]

Challenge #1: Coupled Models

Challenge #2: Competing Objectives

I Want Pareto frontier→ must solve many times

mpay

Vmax

fue

l fl

ow

ra

te

Challenge #3: Solution Quality

I Local vs. global optima

I Sensitivity to initial guess

Page 7: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

Changespecifications

[Adapted from Alonso 2012]

Challenge #1: Coupled Models

Challenge #2: Competing Objectives

I Want Pareto frontier→ must solve many times

mpay

Vmax

fue

l fl

ow

ra

te

Challenge #3: Solution Quality

I Local vs. global optima

I Sensitivity to initial guess

Page 8: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

Changespecifications

[Adapted from Alonso 2012]

Challenge #1: Coupled Models

Challenge #2: Competing Objectives

I Want Pareto frontier→ must solve many times

mpay

Vmax

fue

l fl

ow

ra

te

Challenge #3: Solution Quality

I Local vs. global optima

I Sensitivity to initial guess

Page 9: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

Changespecifications

[Adapted from Alonso 2012]

Insight

I Surprisingly, many relationships in engineering designhave an underlying convex structure.

Benefits

I Globally optimal solutions

I Robust algorithms - no initial guesses; no parametersto tune

I Extremely fast solutions, even for large problems

Page 10: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

Changespecifications

[Adapted from Alonso 2012]

Insight

I Surprisingly, many relationships in engineering designhave an underlying convex structure.

Benefits

I Globally optimal solutions

I Robust algorithms - no initial guesses; no parametersto tune

I Extremely fast solutions, even for large problems

Page 11: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

Changespecifications

Exploitconvexstructure

[Adapted from Alonso 2012]

Insight

I Surprisingly, many relationships in engineering designhave an underlying convex structure.

Benefits

I Globally optimal solutions

I Robust algorithms - no initial guesses; no parametersto tune

I Extremely fast solutions, even for large problems

Page 12: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

Changespecifications

Exploitconvexstructure

[Adapted from Alonso 2012]

Insight

I Surprisingly, many relationships in engineering designhave an underlying convex structure.

Benefits

I Globally optimal solutions

I Robust algorithms - no initial guesses; no parametersto tune

I Extremely fast solutions, even for large problems

Page 13: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

Changespecifications

Exploitconvexstructure

[Adapted from Alonso 2012]

Insight

I Surprisingly, many relationships in engineering designhave an underlying convex structure.

Benefits

I Globally optimal solutions

I Robust algorithms - no initial guesses; no parametersto tune

I Extremely fast solutions, even for large problems

Page 14: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Specifications

Baselinedesign

Evaluateobjective andconstraints

Is the designoptimal?

OptimalDesign

No

Yes

Changedesign

Changespecifications

Exploitconvexstructure

[Adapted from Alonso 2012]

Insight

I Surprisingly, many relationships in engineering designhave an underlying convex structure.

Benefits

I Globally optimal solutions

I Robust algorithms - no initial guesses; no parametersto tune

I Extremely fast solutions, even for large problems

Page 15: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Today’s Talk

Approach Overview

The Power of Lagrange Duality

GP-compatible Modeling for Aircraft Design

Page 16: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Today’s Talk

Approach Overview

The Power of Lagrange Duality

GP-compatible Modeling for Aircraft Design

Page 17: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Optimization Compromizes

least squares vs. simulated annealing

I fast

I reliable

I extremely specific

I still, widely used

I Extremely general

I Slow convergence

I Requireshand-holding

Page 18: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Optimization Compromizes

least squares vs. simulated annealing

I fast

I reliable

I extremely specific

I still, widely used

I Extremely general

I Slow convergence

I Requireshand-holding

Page 19: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Optimization Compromizes

least squares vs. simulated annealing

I fast

I reliable

I extremely specific

I still, widely used

I Extremely general

I Slow convergence

I Requireshand-holding

Page 20: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Optimization Compromizes

least squares

vs.

simulated annealing

I fast

I reliable

I extremely specific

I still, widely used

I Extremely general

I Slow convergence

I Requireshand-holding

Page 21: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Optimization Compromizes

convex programs︷ ︸︸ ︷least squares LP GP SDP simulated annealing

I fast

I reliable

I extremely specific

I still, widely used

I Extremely general

I Slow convergence

I Requireshand-holding

Page 22: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Optimization Compromizes

convex programs︷ ︸︸ ︷least squares LP GP SDP SQP,NLP simulated annealing

I fast

I reliable

I extremely specific

I still, widely used

I Extremely general

I Slow convergence

I Requireshand-holding

Page 23: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

General Nonlinear Program

Decision Variables x ∈ Rnv

Objective Function f0(x) : Rnv → RConstraints 0 ≥ fi(x) : Rnv → R

0 = hi(x) : Rnv → R

I In general, extremely difficult to solve

Convex Program

Same as nonlinear program, except

– fi(x) must be convex

– hi(x) must be affine

I Very efficient to solve

Page 24: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

General Nonlinear Program

Decision Variables x ∈ Rnv

Objective Function f0(x) : Rnv → RConstraints 0 ≥ fi(x) : Rnv → R

0 = hi(x) : Rnv → R

I In general, extremely difficult to solve

Convex Program

Same as nonlinear program, except

– fi(x) must be convex

– hi(x) must be affine

I Very efficient to solve

Page 25: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

General Nonlinear Program

Decision Variables x ∈ Rnv

Objective Function f0(x) : Rnv → RConstraints 0 ≥ fi(x) : Rnv → R

0 = hi(x) : Rnv → R

I In general, extremely difficult to solve

Convex Program

Same as nonlinear program, except

– fi(x) must be convex

– hi(x) must be affine

I Very efficient to solve

Page 26: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

General Nonlinear Program

Decision Variables x ∈ Rnv

Objective Function f0(x) : Rnv → RConstraints 0 ≥ fi(x) : Rnv → R

0 = hi(x) : Rnv → R

I In general, extremely difficult to solve

Convex Program

Same as nonlinear program, except

– fi(x) must be convex

– hi(x) must be affine

I Very efficient to solve

Page 27: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Definition

Monomial Function

m(x) = cn∏

i=1

xaii , c > 0 (e.g., 1

2ρV2CLS)

Posynomial Function: sum of monomials

p(x) =K∑

k=1

ck

n∏i=1

xaiki , ck > 0 (e.g., CD0 +

C2L

πeA)

Geometric Program (GP)

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

with pi posynomial, mi monomialx = (x1, x2, ..., xn) > 0

Page 28: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Definition

Monomial Function

m(x) = cn∏

i=1

xaii , c > 0 (e.g., 1

2ρV2CLS)

Posynomial Function: sum of monomials

p(x) =K∑

k=1

ck

n∏i=1

xaiki , ck > 0 (e.g., CD0 +

C2L

πeA)

Geometric Program (GP)

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

with pi posynomial, mi monomialx = (x1, x2, ..., xn) > 0

Page 29: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Definition

Monomial Function

m(x) = cn∏

i=1

xaii , c > 0 (e.g., 1

2ρV2CLS)

Posynomial Function: sum of monomials

p(x) =K∑

k=1

ck

n∏i=1

xaiki , ck > 0 (e.g., CD0 +

C2L

πeA)

Geometric Program (GP)

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

with pi posynomial, mi monomialx = (x1, x2, ..., xn) > 0

Page 30: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Definition

Monomial Function

m(x) = cn∏

i=1

xaii , c > 0 (e.g., 1

2ρV2CLS)

Posynomial Function: sum of monomials

p(x) =K∑

k=1

ck

n∏i=1

xaiki , ck > 0 (e.g., CD0 +

C2L

πeA)

Geometric Program (GP)

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

with pi posynomial, mi monomialx = (x1, x2, ..., xn) > 0

Page 31: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Convex Formulationvariable change: yi := log xi

I Monomials m(x) = c∏n

i=1 xaii : affine in y after log transform

logm = b + aTy (b = log c)

I Posynomials∑K

k=1 ck∏n

i=1 xaiki : convex in y after log transform

log p = log

(K∑

k=1

ebk+aTk y

)

I GP in convex form

minimize log(∑K0

k=1 exp(b0k + aT0ky))

subject to log(∑Ki

k=1 exp(bik + aTiky))≤ 0, i = 1, . . . ,Np

Gy + h = 0

Page 32: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Convex Formulationvariable change: yi := log xi

I Monomials m(x) = c∏n

i=1 xaii : affine in y after log transform

logm = b + aTy (b = log c)

I Posynomials∑K

k=1 ck∏n

i=1 xaiki : convex in y after log transform

log p = log

(K∑

k=1

ebk+aTk y

)

I GP in convex form

minimize log(∑K0

k=1 exp(b0k + aT0ky))

subject to log(∑Ki

k=1 exp(bik + aTiky))≤ 0, i = 1, . . . ,Np

Gy + h = 0

Page 33: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Convex Formulationvariable change: yi := log xi

I Monomials m(x) = c∏n

i=1 xaii : affine in y after log transform

logm = b + aTy (b = log c)

I Posynomials∑K

k=1 ck∏n

i=1 xaiki : convex in y after log transform

log p = log

(K∑

k=1

ebk+aTk y

)

I GP in convex form

minimize log(∑K0

k=1 exp(b0k + aT0ky))

subject to log(∑Ki

k=1 exp(bik + aTiky))≤ 0, i = 1, . . . ,Np

Gy + h = 0

Page 34: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Convex Formulationvariable change: yi := log xi

I Monomials m(x) = c∏n

i=1 xaii : affine in y after log transform

logm = b + aTy (b = log c)

I Posynomials∑K

k=1 ck∏n

i=1 xaiki : convex in y after log transform

log p = log

(K∑

k=1

ebk+aTk y

)

I GP in convex form

minimize log(∑K0

k=1 exp(b0k + aT0ky))

subject to log(∑Ki

k=1 exp(bik + aTiky))≤ 0, i = 1, . . . ,Np

Gy + h = 0

Page 35: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Convex Formulation

a < 0

a == 0

0 < a < 1

a == 1a

> 1

monomials

a < 0

a == 0

0 < a < 1

a == 1

a >

1

monomials (log−space)

.01x−2 +x

0.2 +.00006x4

.03x−1+.8x

0.2

.2x

1.5

posynomials

.01x−2 +x

0.2 +.00006x4

.03x−1 +.8x

0.2

.2x

1.5

posynomials (log−space)

Page 36: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Convex Formulation

a < 0

a == 0

0 < a < 1

a == 1a

> 1

monomials

a < 0

a == 0

0 < a < 1

a == 1

a >

1

monomials (log−space)

.01x−2 +x

0.2 +.00006x4

.03x−1+.8x

0.2

.2x

1.5

posynomials

.01x−2 +x

0.2 +.00006x4

.03x−1 +.8x

0.2

.2x

1.5

posynomials (log−space)

Page 37: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Convex Formulation

a < 0

a == 0

0 < a < 1

a == 1a

> 1

monomials

a < 0

a == 0

0 < a < 1

a == 1

a >

1

monomials (log−space)

.01x−2 +x

0.2 +.00006x4

.03x−1+.8x

0.2

.2x

1.5

posynomials

.01x−2 +x

0.2 +.00006x4

.03x−1 +.8x

0.2

.2x

1.5

posynomials (log−space)

Page 38: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Geometric Program: Convex Formulation

a < 0

a == 0

0 < a < 1

a == 1a

> 1

monomials

a < 0

a == 0

0 < a < 1

a == 1

a >

1

monomials (log−space)

.01x−2 +x

0.2 +.00006x4

.03x−1+.8x

0.2

.2x

1.5

posynomials

.01x−2 +x

0.2 +.00006x4

.03x−1 +.8x

0.2

.2x

1.5

posynomials (log−space)

Page 39: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Solution of Geometric Programs

Interior-point methods

u−3 −2 −1 0 1

−5

0

5

10

c

x* x*(10)

Figures: [Boyd 2004]

Benefits:

I Globally optimal solution, guaranteed

I Robust: no initial guesses or parameter tuning

I Off-the-shelf solvers

Boyd GP benchmarks (2005) [1]

I dense GP: 1,000 variables; 10,000 constraints: lessthan 1 minute

I sparse GP: 10,000 variables; 1,000,000 constraints:“minutes”

Page 40: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Solution of Geometric Programs

Interior-point methods

u−3 −2 −1 0 1

−5

0

5

10

c

x* x*(10)

Figures: [Boyd 2004]

Benefits:

I Globally optimal solution, guaranteed

I Robust: no initial guesses or parameter tuning

I Off-the-shelf solvers

Boyd GP benchmarks (2005) [1]

I dense GP: 1,000 variables; 10,000 constraints: lessthan 1 minute

I sparse GP: 10,000 variables; 1,000,000 constraints:“minutes”

Page 41: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Running Example

minimizeA,S,CD ,CL,W ,Ww ,V

1

2ρV 2CDS

subject to

CD breakdown 1 ≥ (CDA0)

CDS+

CDp

CD

+C 2L

CDπAe

CL definition 1 ≥ 2W

ρV 2CLS

weight breakdown 1 ≥ W0

W+

Ww

W

wing weight 1 ≥ 45.42S

Ww

+ 8.71× 10−5NliftA3/2√W0WS

Wwτ

stall speed 1 ≥ 2W

ρV 2minSCL,max

CONSTANTS

CDA0 0.031

CDp 0.0095

CLmax 1.5

Nult 3.8

Vmin 22

W0 4940

e 0.95

rho 1.23

tau 0.12

Page 42: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Running Example

minimizeA,S,CD ,CL,W ,Ww ,V

1

2ρV 2CDS

subject to

CD breakdown 1 ≥ (CDA0)

CDS+

CDp

CD

+C 2L

CDπAe

CL definition 1 ≥ 2W

ρV 2CLS

weight breakdown 1 ≥ W0

W+

Ww

W

wing weight 1 ≥ 45.42S

Ww

+ 8.71× 10−5NliftA3/2√W0WS

Wwτ

stall speed 1 ≥ 2W

ρV 2minSCL,max

CONSTANTS

CDA0 0.031

CDp 0.0095

CLmax 1.5

Nult 3.8

Vmin 22

W0 4940

e 0.95

rho 1.23

tau 0.12

Page 43: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

GP Parameterization

c A A

map

0

1/2

1 1

1 1

1 1/π

2 2

3 1

3 1

4 45.42

4 8.7e − 5

5 2

CDA0 ρ CDp e W0 Nlift τ Vmin CLmax

1

1

1

−1

−1

1

1/2 1 −1

−1 −2 −1

A S CD CL W Ww V

1 1 2

−1 −1

−1

−1 −1 2

−1 −1 1 −2

−1

−1 1

1 −1

3/2 1/2 1/2 −1

−1 1

Page 44: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Globally Optimal Solution

A 8.792

S 16.79

CD 0.02269

CL 0.5456

W 7495

Ww 2555

V 36.48

OBJECTIVE VALUE: 311.7159

Solution is:

I Feasible (satisfies all constraints)

I Globally optimal (no other feasiblesolution has better objective value)

Page 45: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Globally Optimal Solution

A 8.792

S 16.79

CD 0.02269

CL 0.5456

W 7495

Ww 2555

V 36.48

OBJECTIVE VALUE: 311.7159

Solution is:

I Feasible (satisfies all constraints)

I Globally optimal (no other feasiblesolution has better objective value)

Page 46: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Globally Optimal Solution

A 8.792

S 16.79

CD 0.02269

CL 0.5456

W 7495

Ww 2555

V 36.48

OBJECTIVE VALUE: 311.7159

Solution is:

I Feasible (satisfies all constraints)

I Globally optimal (no other feasiblesolution has better objective value)

Page 47: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Today’s Talk

Approach Overview

The Power of Lagrange Duality

GP-compatible Modeling for Aircraft Design

Page 48: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Lagrange Dual of GP

Primal problem (in convex form):

minimize logK0∑k=1

exp(aT0ky + b0k)

subject to logKi∑k=1

exp(aTiky + bik) ≤ 0, i = 1, ...,m, (1)

Lagrangian and dual function:

L(y , z ,λ,ν) = logK0∑k=1

exp z0k +m∑i=1

λi logKi∑k=1

exp zik +m∑i=0

νTi (Aiy + bi − z i)

g(λ,ν) = infy ,z

L(y , z ,λ,ν).

Page 49: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Lagrange Dual of GP

Primal problem (in convex form):

minimize logK0∑k=1

exp(aT0ky + b0k)

subject to logKi∑k=1

exp(aTiky + bik) ≤ 0, i = 1, ...,m, (1)

Lagrangian and dual function:

L(y , z ,λ,ν) = logK0∑k=1

exp z0k +m∑i=1

λi logKi∑k=1

exp zik +m∑i=0

νTi (Aiy + bi − z i)

g(λ,ν) = infy ,z

L(y , z ,λ,ν).

Page 50: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Lagrange Dual of GP

maximizem∑i=0

[νTi bi −

Ki∑k=1

νik logνik

1Tν i

]

subject tom∑i=0

νTi Ai = 0

ν i ≥ 0, i = 0, ...,m

1Tν0 = 1.

I An equality-constrained entropy maximization

I (unnormalized) probability distributions ν i satisfy 1Tν i = λi

Page 51: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Lagrange Dual of GP

maximizem∑i=0

[νTi bi −

Ki∑k=1

νik logνik

1Tν i

]

subject tom∑i=0

νTi Ai = 0

ν i ≥ 0, i = 0, ...,m

1Tν0 = 1.

I An equality-constrained entropy maximization

I (unnormalized) probability distributions ν i satisfy 1Tν i = λi

Page 52: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Lagrange Dual of GP

maximizem∑i=0

[νTi bi −

Ki∑k=1

νik logνik

1Tν i

]

subject tom∑i=0

νTi Ai = 0

ν i ≥ 0, i = 0, ...,m

1Tν0 = 1.

I An equality-constrained entropy maximization

I (unnormalized) probability distributions ν i satisfy 1Tν i = λi

Page 53: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Constraint Sensitivities

I Consider perturbed GP:

minimizeK0∑k=1

c0kxa0k

subject toKi∑k=1

cikxaik ≤ ui , i = 1, ...,m.

I Define p∗(u) ≡ optimal objective value of perturbed GP

I Extremely useful fact:

∂ log p∗(u)

∂ log ui

∣∣∣∣u=1

=∂(

p∗(u)p∗(1)

)∂(ui1

)∣∣∣∣∣∣u=1

= −λi

I Best of all, modern solvers determine λi ’s for free

Page 54: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Constraint Sensitivities

I Consider perturbed GP:

minimizeK0∑k=1

c0kxa0k

subject toKi∑k=1

cikxaik ≤ ui , i = 1, ...,m.

I Define p∗(u) ≡ optimal objective value of perturbed GP

I Extremely useful fact:

∂ log p∗(u)

∂ log ui

∣∣∣∣u=1

=∂(

p∗(u)p∗(1)

)∂(ui1

)∣∣∣∣∣∣u=1

= −λi

I Best of all, modern solvers determine λi ’s for free

Page 55: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Constraint Sensitivities

I Consider perturbed GP:

minimizeK0∑k=1

c0kxa0k

subject toKi∑k=1

cikxaik ≤ ui , i = 1, ...,m.

I Define p∗(u) ≡ optimal objective value of perturbed GP

I Extremely useful fact:

∂ log p∗(u)

∂ log ui

∣∣∣∣u=1

=∂(

p∗(u)p∗(1)

)∂(ui1

)∣∣∣∣∣∣u=1

= −λi

I Best of all, modern solvers determine λi ’s for free

Page 56: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Constraint Sensitivities

I Consider perturbed GP:

minimizeK0∑k=1

c0kxa0k

subject toKi∑k=1

cikxaik ≤ ui , i = 1, ...,m.

I Define p∗(u) ≡ optimal objective value of perturbed GP

I Extremely useful fact:

∂ log p∗(u)

∂ log ui

∣∣∣∣u=1

=∂(

p∗(u)p∗(1)

)∂(ui1

)∣∣∣∣∣∣u=1

= −λi

I Best of all, modern solvers determine λi ’s for free

Page 57: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Running Example – Constraint Sensitivities

OBJECTIVE --> D

A 8.792

S 16.79

CD 0.02269

CL 0.5456

W 7495

Ww 2555

V 36.48

weight breakdown 139.37%

CD breakdown 100.00%

CL definition 100.00%

induced drag model 50.00%

wing weight model 47.51%

landing stall speed 22.71%

fuselage drag model 8.14%

DV

8.572

30.55

0.04206

0.8983

8859

3919

22.91

175.00%

100.00%

150.00%

75.00%

77.41%

0.00%

2.41%

D/V

6.307

14.69

0.01548

0.2699

6561

1621

51.87

114.71%

100.00%

50.00%

25.00%

28.34%

56.37%

13.63%

Page 58: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Running Example – Constraint Sensitivities

OBJECTIVE --> D

A 8.792

S 16.79

CD 0.02269

CL 0.5456

W 7495

Ww 2555

V 36.48

weight breakdown 139.37%

CD breakdown 100.00%

CL definition 100.00%

induced drag model 50.00%

wing weight model 47.51%

landing stall speed 22.71%

fuselage drag model 8.14%

DV

8.572

30.55

0.04206

0.8983

8859

3919

22.91

175.00%

100.00%

150.00%

75.00%

77.41%

0.00%

2.41%

D/V

6.307

14.69

0.01548

0.2699

6561

1621

51.87

114.71%

100.00%

50.00%

25.00%

28.34%

56.37%

13.63%

Page 59: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Running Example – Constraint Sensitivities

OBJECTIVE --> D

A 8.792

S 16.79

CD 0.02269

CL 0.5456

W 7495

Ww 2555

V 36.48

weight breakdown 139.37%

CD breakdown 100.00%

CL definition 100.00%

induced drag model 50.00%

wing weight model 47.51%

landing stall speed 22.71%

fuselage drag model 8.14%

DV

8.572

30.55

0.04206

0.8983

8859

3919

22.91

175.00%

100.00%

150.00%

75.00%

77.41%

0.00%

2.41%

D/V

6.307

14.69

0.01548

0.2699

6561

1621

51.87

114.71%

100.00%

50.00%

25.00%

28.34%

56.37%

13.63%

Page 60: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Constant Sensitivities

GP with fixed variables x

minimizeK0∑k=1

c0k xa0kxa0k

subject toKi∑k=1

cik xaikxaik ≤ 1, i = 1, ...,m, (2)

Dual variables encode sensitivity of optimum to fixedvariables:

∂ log p∗

∂ log xj=

m∑i=0

νTi a

(j)i

Running Example

SNSTVTY CONST VALUE

------- ----- -----

-108.50% W0 4940

50.00% e 0.95

45.41% Vmin 22

-41.86% CDp 0.0095

-33.33% Nult 3.8

33.33% tau 0.12

22.71% CLmax 1.5

22.71% rho 1.23

-8.138% CDA0 0.031

Page 61: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Constant Sensitivities

GP with fixed variables x

minimizeK0∑k=1

c0k xa0kxa0k

subject toKi∑k=1

cik xaikxaik ≤ 1, i = 1, ...,m, (2)

Dual variables encode sensitivity of optimum to fixedvariables:

∂ log p∗

∂ log xj=

m∑i=0

νTi a

(j)i

Running Example

SNSTVTY CONST VALUE

------- ----- -----

-108.50% W0 4940

50.00% e 0.95

45.41% Vmin 22

-41.86% CDp 0.0095

-33.33% Nult 3.8

33.33% tau 0.12

22.71% CLmax 1.5

22.71% rho 1.23

-8.138% CDA0 0.031

Page 62: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Some Useful Bounds

Dual Sensitivity Analysis

I Start with feasible solution p∗(u = 1)

I Perturb design constraints (via u)

I Performance bound:

log p∗(u) ≥ log p∗(1) + λTu

I An optimistic estimate

Design Averaging

I Consider two designs θ1, θ2, withobjective values p∗

1 , p∗2

I Form geometric mean design

θ(i)3 =

√θ

(i)1 θ

(i)2

I Performance bound:

p∗3 ≤

√p∗

1p∗2

I A pessimistic estimate

Page 63: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Some Useful Bounds

Dual Sensitivity Analysis

I Start with feasible solution p∗(u = 1)

I Perturb design constraints (via u)

I Performance bound:

log p∗(u) ≥ log p∗(1) + λTu

I An optimistic estimate

Design Averaging

I Consider two designs θ1, θ2, withobjective values p∗

1 , p∗2

I Form geometric mean design

θ(i)3 =

√θ

(i)1 θ

(i)2

I Performance bound:

p∗3 ≤

√p∗

1p∗2

I A pessimistic estimate

Page 64: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Some Useful Bounds

Dual Sensitivity Analysis

I Start with feasible solution p∗(u = 1)

I Perturb design constraints (via u)

I Performance bound:

log p∗(u) ≥ log p∗(1) + λTu

I An optimistic estimate

Design Averaging

I Consider two designs θ1, θ2, withobjective values p∗

1 , p∗2

I Form geometric mean design

θ(i)3 =

√θ

(i)1 θ

(i)2

I Performance bound:

p∗3 ≤

√p∗

1p∗2

I A pessimistic estimate

Page 65: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Some Useful Bounds

Dual Sensitivity Analysis

I Start with feasible solution p∗(u = 1)

I Perturb design constraints (via u)

I Performance bound:

log p∗(u) ≥ log p∗(1) + λTu

I An optimistic estimate

Design Averaging

I Consider two designs θ1, θ2, withobjective values p∗

1 , p∗2

I Form geometric mean design

θ(i)3 =

√θ

(i)1 θ

(i)2

I Performance bound:

p∗3 ≤

√p∗

1p∗2

I A pessimistic estimate

Page 66: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Some Useful Bounds

Dual Sensitivity Analysis

I Start with feasible solution p∗(u = 1)

I Perturb design constraints (via u)

I Performance bound:

log p∗(u) ≥ log p∗(1) + λTu

I An optimistic estimate

Design Averaging

I Consider two designs θ1, θ2, withobjective values p∗

1 , p∗2

I Form geometric mean design

θ(i)3 =

√θ

(i)1 θ

(i)2

I Performance bound:

p∗3 ≤

√p∗

1p∗2

I A pessimistic estimate

Page 67: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Some Useful Bounds

Dual Sensitivity Analysis

I Start with feasible solution p∗(u = 1)

I Perturb design constraints (via u)

I Performance bound:

log p∗(u) ≥ log p∗(1) + λTu

I An optimistic estimate

Design Averaging

I Consider two designs θ1, θ2, withobjective values p∗

1 , p∗2

I Form geometric mean design

θ(i)3 =

√θ

(i)1 θ

(i)2

I Performance bound:

p∗3 ≤

√p∗

1p∗2

I A pessimistic estimate

Page 68: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Some Useful Bounds

Dual Sensitivity Analysis

I Start with feasible solution p∗(u = 1)

I Perturb design constraints (via u)

I Performance bound:

log p∗(u) ≥ log p∗(1) + λTu

I An optimistic estimate

Design Averaging

I Consider two designs θ1, θ2, withobjective values p∗

1 , p∗2

I Form geometric mean design

θ(i)3 =

√θ

(i)1 θ

(i)2

I Performance bound:

p∗3 ≤

√p∗

1p∗2

I A pessimistic estimate

Page 69: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Some Useful Bounds

Dual Sensitivity Analysis

I Start with feasible solution p∗(u = 1)

I Perturb design constraints (via u)

I Performance bound:

log p∗(u) ≥ log p∗(1) + λTu

I An optimistic estimate

Design Averaging

I Consider two designs θ1, θ2, withobjective values p∗

1 , p∗2

I Form geometric mean design

θ(i)3 =

√θ

(i)1 θ

(i)2

I Performance bound:

p∗3 ≤

√p∗

1p∗2

I A pessimistic estimate

Page 70: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Feasibility Analysis

When constraints cannot all be satisfied, GP solvers provide a mathematical certificatethat no feasible point exists.

In this case, look for closest feasible point:

Original GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

Closest Feasible Point GP

minimize ssubject to pi(x) ≤ s, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

The closest feasible point GP is always feasible, and its optimal point is within100(s − 1)% of satisfying the original inequality constraints.

Page 71: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Feasibility Analysis

When constraints cannot all be satisfied, GP solvers provide a mathematical certificatethat no feasible point exists.

In this case, look for closest feasible point:

Original GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

Closest Feasible Point GP

minimize ssubject to pi(x) ≤ s, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

The closest feasible point GP is always feasible, and its optimal point is within100(s − 1)% of satisfying the original inequality constraints.

Page 72: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Feasibility Analysis

When constraints cannot all be satisfied, GP solvers provide a mathematical certificatethat no feasible point exists.

In this case, look for closest feasible point:

Original GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

Closest Feasible Point GP

minimize ssubject to pi(x) ≤ s, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

The closest feasible point GP is always feasible, and its optimal point is within100(s − 1)% of satisfying the original inequality constraints.

Page 73: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Today’s Talk

Approach Overview

The Power of Lagrange Duality

GP-compatible Modeling for Aircraft Design

Page 74: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Conceptual Design – Modeling Summary

I Fuselage Pressure Loads

I Fuselage Bending Loads

I Fuselage Weight

I Steady Level Flight Relations

I Wing Moments and Stresses

I Wing Weight

I Stability

I Tail Moments and Stresses

I Tail Weight

I Engine Weight

I Turbine Cycle Analysis

I Noise

I CG Envelope

I Active Gust Response

I Wing Profile Drag

I V-speeds and critical loading cases

I Wing Induced Drag

I Tail Drag

I Fuselage Drag

I Interference Drags

I Airfoil Shape Optimization

I Laminar Flow Control

I Compressibility Effects

I Propulsive Efficiency

I Blade Element Momentum Theory

I APU Sizing

I Hydraulic, Fuel, & Electrical SystemWeights

I Mission Breakdown and Fuel Burn

I Cruise Climb

I Loiter Performance/Endurance

I Takeoff Distance & 50’ obstacle

clearance

I Landing Distance

I Spoiler Sizing

I Climb Performance

I Engine-Out Operation

I Windmilling Drag

I Maneuverability

I High Lift System Sizing

I Control Surface Sizing

I Landing Gear Sizing

I Engine Ground Clearance

I Tail Strike Clearance

I Maintenance Costs

I Material Costs

I Manufacturability

I Assembly/Integration Time and Cost

I Fastener Count

I Supply Chain Dynamics

Page 75: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Conceptual Design – Modeling Summary

I Fuselage Pressure Loads

I Fuselage Bending Loads

I Fuselage Weight

I Steady Level Flight Relations

I Wing Moments and Stresses

I Wing Weight

I Stability

I Tail Moments and Stresses

I Tail Weight

I Engine Weight

I Turbine Cycle Analysis

I Noise

I CG Envelope

I Active Gust Response

I Wing Profile Drag

I V-speeds and critical loading cases

I Wing Induced Drag

I Tail Drag

I Fuselage Drag

I Interference Drags

I Airfoil Shape Optimization

I Laminar Flow Control

I Compressibility Effects

I Propulsive Efficiency

I Blade Element Momentum Theory

I APU Sizing

I Hydraulic, Fuel, & Electrical SystemWeights

I Mission Breakdown and Fuel Burn

I Cruise Climb

I Loiter Performance/Endurance

I Takeoff Distance & 50’ obstacle

clearance

I Landing Distance

I Spoiler Sizing

I Climb Performance

I Engine-Out Operation

I Windmilling Drag

I Maneuverability

I High Lift System Sizing

I Control Surface Sizing

I Landing Gear Sizing

I Engine Ground Clearance

I Tail Strike Clearance

I Maintenance Costs

I Material Costs

I Manufacturability

I Assembly/Integration Time and Cost

I Fastener Count

I Supply Chain Dynamics

Page 76: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Conceptual Design – Modeling Summary

I Fuselage Pressure Loads

I Fuselage Bending Loads

I Fuselage Weight

I Steady Level Flight Relations

I Wing Moments and Stresses

I Wing Weight

I Stability

I Tail Moments and Stresses

I Tail Weight

I Engine Weight

I Turbine Cycle Analysis

I Noise

I CG Envelope

I Active Gust Response

I Wing Profile Drag

I V-speeds and critical loading cases

I Wing Induced Drag

I Tail Drag

I Fuselage Drag

I Interference Drags

I Airfoil Shape Optimization

I Laminar Flow Control

I Compressibility Effects

I Propulsive Efficiency

I Blade Element Momentum Theory

I APU Sizing

I Hydraulic, Fuel, & Electrical SystemWeights

I Mission Breakdown and Fuel Burn

I Cruise Climb

I Loiter Performance/Endurance

I Takeoff Distance & 50’ obstacle

clearance

I Landing Distance

I Spoiler Sizing

I Climb Performance

I Engine-Out Operation

I Windmilling Drag

I Maneuverability

I High Lift System Sizing

I Control Surface Sizing

I Landing Gear Sizing

I Engine Ground Clearance

I Tail Strike Clearance

I Maintenance Costs

I Material Costs

I Manufacturability

I Assembly/Integration Time and Cost

I Fastener Count

I Supply Chain Dynamics

Page 77: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Conceptual Design – Modeling Summary

I Fuselage Pressure Loads

I Fuselage Bending Loads

I Fuselage Weight

I Steady Level Flight Relations

I Wing Moments and Stresses

I Wing Weight

I Stability

I Tail Moments and Stresses

I Tail Weight

I Engine Weight

I Turbine Cycle Analysis

I Noise

I CG Envelope

I Active Gust Response

I Wing Profile Drag

I V-speeds and critical loading cases

I Wing Induced Drag

I Tail Drag

I Fuselage Drag

I Interference Drags

I Airfoil Shape Optimization

I Laminar Flow Control

I Compressibility Effects

I Propulsive Efficiency

I Blade Element Momentum Theory

I APU Sizing

I Hydraulic, Fuel, & Electrical SystemWeights

I Mission Breakdown and Fuel Burn

I Cruise Climb

I Loiter Performance/Endurance

I Takeoff Distance & 50’ obstacle

clearance

I Landing Distance

I Spoiler Sizing

I Climb Performance

I Engine-Out Operation

I Windmilling Drag

I Maneuverability

I High Lift System Sizing

I Control Surface Sizing

I Landing Gear Sizing

I Engine Ground Clearance

I Tail Strike Clearance

I Maintenance Costs

I Material Costs

I Manufacturability

I Assembly/Integration Time and Cost

I Fastener Count

I Supply Chain Dynamics

Page 78: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Fitting Reduced-Order GP-compatible Models

disciplinaryanalysisinputs output(s)

I GP-compatible models can approximate anylog-convex data [Boyd 2007]

I Given set of data points(x1, y1), . . . , (xm, ym) ∈ Rn × R

I Minimize fitting error ||y − f (x)||, subject to f ∈ FI Several choices for F , e.g.

I Max-affine functions [Magnani and Boyd 2008]I Softmax affine functions [Hoburg et al. 2013]I Implicit posynomials [Hoburg et al. 2013]

I Fitting problem solved offline using trust regionNewton methods

I Many extensions, e.g. conservative fitting, sparsefitting

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729scaled softmax: RMS error = 0.12657implicit softmax: RMS error = 0.011219

Page 79: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Fitting Reduced-Order GP-compatible Models

disciplinaryanalysisinputs output(s)

I GP-compatible models can approximate anylog-convex data [Boyd 2007]

I Given set of data points(x1, y1), . . . , (xm, ym) ∈ Rn × R

I Minimize fitting error ||y − f (x)||, subject to f ∈ FI Several choices for F , e.g.

I Max-affine functions [Magnani and Boyd 2008]I Softmax affine functions [Hoburg et al. 2013]I Implicit posynomials [Hoburg et al. 2013]

I Fitting problem solved offline using trust regionNewton methods

I Many extensions, e.g. conservative fitting, sparsefitting

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729scaled softmax: RMS error = 0.12657implicit softmax: RMS error = 0.011219

Page 80: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Fitting Reduced-Order GP-compatible Models

disciplinaryanalysisinputs output(s)

I GP-compatible models can approximate anylog-convex data [Boyd 2007]

I Given set of data points(x1, y1), . . . , (xm, ym) ∈ Rn × R

I Minimize fitting error ||y − f (x)||, subject to f ∈ FI Several choices for F , e.g.

I Max-affine functions [Magnani and Boyd 2008]I Softmax affine functions [Hoburg et al. 2013]I Implicit posynomials [Hoburg et al. 2013]

I Fitting problem solved offline using trust regionNewton methods

I Many extensions, e.g. conservative fitting, sparsefitting

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729scaled softmax: RMS error = 0.12657implicit softmax: RMS error = 0.011219

Page 81: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Fitting Reduced-Order GP-compatible Models

disciplinaryanalysisinputs output(s)

I GP-compatible models can approximate anylog-convex data [Boyd 2007]

I Given set of data points(x1, y1), . . . , (xm, ym) ∈ Rn × R

I Minimize fitting error ||y − f (x)||, subject to f ∈ F

I Several choices for F , e.g.I Max-affine functions [Magnani and Boyd 2008]I Softmax affine functions [Hoburg et al. 2013]I Implicit posynomials [Hoburg et al. 2013]

I Fitting problem solved offline using trust regionNewton methods

I Many extensions, e.g. conservative fitting, sparsefitting

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729scaled softmax: RMS error = 0.12657implicit softmax: RMS error = 0.011219

Page 82: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Fitting Reduced-Order GP-compatible Models

disciplinaryanalysisinputs output(s)

I GP-compatible models can approximate anylog-convex data [Boyd 2007]

I Given set of data points(x1, y1), . . . , (xm, ym) ∈ Rn × R

I Minimize fitting error ||y − f (x)||, subject to f ∈ FI Several choices for F , e.g.

I Max-affine functions [Magnani and Boyd 2008]I Softmax affine functions [Hoburg et al. 2013]I Implicit posynomials [Hoburg et al. 2013]

I Fitting problem solved offline using trust regionNewton methods

I Many extensions, e.g. conservative fitting, sparsefitting

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729scaled softmax: RMS error = 0.12657implicit softmax: RMS error = 0.011219

Page 83: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Fitting Reduced-Order GP-compatible Models

disciplinaryanalysisinputs output(s)

I GP-compatible models can approximate anylog-convex data [Boyd 2007]

I Given set of data points(x1, y1), . . . , (xm, ym) ∈ Rn × R

I Minimize fitting error ||y − f (x)||, subject to f ∈ FI Several choices for F , e.g.

I Max-affine functions [Magnani and Boyd 2008]I Softmax affine functions [Hoburg et al. 2013]I Implicit posynomials [Hoburg et al. 2013]

I Fitting problem solved offline using trust regionNewton methods

I Many extensions, e.g. conservative fitting, sparsefitting

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729scaled softmax: RMS error = 0.12657implicit softmax: RMS error = 0.011219

Page 84: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Fitting Reduced-Order GP-compatible Models

disciplinaryanalysisinputs output(s)

I GP-compatible models can approximate anylog-convex data [Boyd 2007]

I Given set of data points(x1, y1), . . . , (xm, ym) ∈ Rn × R

I Minimize fitting error ||y − f (x)||, subject to f ∈ FI Several choices for F , e.g.

I Max-affine functions [Magnani and Boyd 2008]I Softmax affine functions [Hoburg et al. 2013]I Implicit posynomials [Hoburg et al. 2013]

I Fitting problem solved offline using trust regionNewton methods

I Many extensions, e.g. conservative fitting, sparsefitting

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729

−2 −1 0 1 2−1

0

1

2

3

4

5

6

7

8

y = log x

log

z

input datamax−affine: RMS error = 0.17764softmax−affine: RMS error = 0.12729scaled softmax: RMS error = 0.12657implicit softmax: RMS error = 0.011219

Page 85: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 86: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 87: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 88: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 89: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 90: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 91: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 92: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 93: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 94: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 95: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 96: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Handling non-GP-compatible models

I Primary limitation of GP approach:models must be log-convex

I Can handle more general modelsusing:

I Nonlinear change of variablesI Signomial programmingI Sequential convex programming

I Similar to solving a nonlinearprogram, but much work offloadedas GP

minimize p0(x)subject to pi(x) ≤ 1, i = 1, ...,Np,

mj(x) = 1, j = 1, ...,Nm

q(x) ≤ 1

Sketch of sequential GP approach

x35

q(x

)

Page 97: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Take-aways

I Importance of mathematical structure

I Key to tractability:

convexity

I Result: reliable and efficient optimization that scalesto large problems

Looking Ahead

I Automatic identification of convexity in data

I Understanding reparameterizations

I (Community) development of standard modellibraries

Page 98: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Take-aways

I Importance of mathematical structure

I Key to tractability:

convexity

I Result: reliable and efficient optimization that scalesto large problems

Looking Ahead

I Automatic identification of convexity in data

I Understanding reparameterizations

I (Community) development of standard modellibraries

Page 99: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Take-aways

I Importance of mathematical structure

I Key to tractability: convexity

I Result: reliable and efficient optimization that scalesto large problems

Looking Ahead

I Automatic identification of convexity in data

I Understanding reparameterizations

I (Community) development of standard modellibraries

Page 100: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Take-aways

I Importance of mathematical structure

I Key to tractability: convexity

I Result: reliable and efficient optimization that scalesto large problems

Looking Ahead

I Automatic identification of convexity in data

I Understanding reparameterizations

I (Community) development of standard modellibraries

Page 101: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Take-aways

I Importance of mathematical structure

I Key to tractability: convexity

I Result: reliable and efficient optimization that scalesto large problems

Looking Ahead

I Automatic identification of convexity in data

I Understanding reparameterizations

I (Community) development of standard modellibraries

Page 102: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Take-aways

I Importance of mathematical structure

I Key to tractability: convexity

I Result: reliable and efficient optimization that scalesto large problems

Looking Ahead

I Automatic identification of convexity in data

I Understanding reparameterizations

I (Community) development of standard modellibraries

Page 103: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Take-aways

I Importance of mathematical structure

I Key to tractability: convexity

I Result: reliable and efficient optimization that scalesto large problems

Looking Ahead

I Automatic identification of convexity in data

I Understanding reparameterizations

I (Community) development of standard modellibraries

Page 104: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

Thank you

Page 105: Introduction to Geometric Programming Based Aircraft Designadl.stanford.edu/2013_MDO_Consortium/Agenda_files/dualgp.pdfIntroduction to Geometric Programming Based Aircraft Design Warren

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Evin J Cramer, JE Dennis, Jr, Paul D Frank, Robert Michael Lewis, and Gregory R Shubin.

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Nathan P. Tedford and Joaquim R.R.A. Martins.

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Bilevel integrated system synthesis with response surfaces.AIAA Journal, 38(8):1479–1485, 2000.

Jaroslaw Sobieszczanski-Sobieski, Troy D Altus, Matthew Phillips, and Robert Sandusky.

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Wind Energy Explained: Theory, Design and Application.John Wiley & Sons, 2010.

Mark Drela.

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Warren Hoburg.

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Warren Hoburg and Pieter Abbeel.

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Warren Hoburg and Pieter Abbeel.

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