Virtual Prototyping and Analysis

Ed Winkler

Technical FellowHuman Systems

Boeing Phantom WorksSt. Louis

Percentiles

Male / Female

60s 70s 80s 90s

F-15 (5-95)

F/A-18 (3-98)

F-22 (1-99)

JSF(JPATS)

Progression of AccommodationExpansion

Male only

Background Current Accommodation Problems

(AFI 48-123 = 64” to 77” Standing height and 34” to 40” Sitting Height.)

Ref: Dr. Zehner

BackgroundJPATS (Joint Primary Aircraft Training System)

• 1994 - Congress directed that the JPATS would accommodate 95% of female military population.

• This translates to a 58” Standing Height and 31” Sitting Height minimum

Ref: Dr. Zehner

Sum of 5th %ile Parts= 136.89 cm 5th %ile Height= 152.50 cm Difference= 15.61 cm

Sum of 95th %ile Parts= 188.81 cm 95th %ile Height= 173.06 cm Difference= 15.75 cm

SAMPLE SIZE=3235

Percentiles Are Not Additive

*From Robinette and McConville 1982

Percentile Fallacy

If 5th to 95th percentile limits are applied to each of the following:

0-5% 95-100%Sitting Ht.

Butt-Knee Lth

Knee Ht. Sit.

Shoulder Brth

Functional Reach

90%

82%

78%

71%

67%

Remaining Percentage

2

2

2Average

Subject 2

Subject 2

Average is Different From Everyone!

Subject 1Subject 1

Subject 3

x y z

2 3 1

1 2 3

3 1 2

• Average Person? Does Not Exist (Daniels 1952)• Summary Statistics Are Not Good Data Reduction Tools for Engineering Models

1

2

33

2

1

Subject 3

3

1

2

Average 2 2 2

Boundary Points and Principal Components(JPATS Cases)

SECOND

COMPONENT

FIRST COMPONENT

1

2

3

4

5

6

7 8

Challenge: Is a biomechanical model needed? Model actual data instead?

Can Also Create Dynamic 3-D Simulations with 3-D Scans

A CAESAR Subject Standing Pose Segmented and Joint Center Linked Then Repositioned to a Seated Pose

A 10 segment CAESAR subject standing pose.

Can Use 3-D Scans to Characterize Cases

• With 3-D Have a Model so Can Have Set of 3-D Cases

• Can Visualize Real People As a Reference During Design

•3-D Shape or Size Statistics are Limited

•To Select Cases Still Limited to Traditional Measurements

Advantage

Issues and Challenges

Distributed Cases

1

2

3

45

6

7 8

9

Issues: 1) How to Select Measurements 2) Where to Select Cases

Characterizing Populations

Left Pupil Distribution

Right Pupil Distribution

Center of Gravity Distribution

HGU 55/P Helmet

Right Ear Distribution

Challenge: Full Population Data is Difficult to Visualize

Background Small Subject ( 5’- 0”) in the T-38

Inertial reels locked

Eye Height

Shoulder Height

Arm SpanButtock-Knee Length

Knee Height Sitting Height

Stature and Sitting Height Are Not Enough

• Original design eye line = -10 deg.

• Base of windscreen wiper

• Verified through study flights as

minimum for no-flap landing

Male

Female

Military Population

Pilot Population

91% 96%

47% 91%

T-1 Results: VisionMinimum Eye Height = 29.6”

Percent Accommodated

Male

Female

MilitaryPopulation

Pilot Population

• To recover from a blown tire on landing

• Pilot tightly restrained

T-38 Results: RuddersMinimum Leg Length = 43”

95% 97%

46% 81%

Requirement: Full rudder and full brake at the same time

Percent Accommodated:

EXPANDED ACCOMMODATION5-95 PERCENTILE DESIGN POPULATION WITH JPATS OVERLAY5-95 PERCENTILE DESIGN POPULATION WITH JPATS OVERLAYCOMPARISON.COMPARISON.

3535 4040

5555

5050

4545

4040

3535

3030 4545

Approx. 5-95%Approx. 5-95%MALEMALEUSAF RangeUSAF Range

COMBINEDCOMBINEDACCOMMODATIONACCOMMODATION

- JPATS Manikins- JPATS Manikins

SITTING HT. (in.l)SITTING HT. (in.l)

LEG

LE

NG

TH

(in

.)LE

G L

EN

GT

H (

in.)

15.3 inch

6.3 inch

Large Male97.5 Percentile

Small Female2.5 Percentile

Accommodation Limits

31.0 32.0 33.0 34.0 35.0 36.0 37.0 38.0 39.0 40.0

F-22 Requirements.5 - 99.5 %ile Male AF Pilots

F-22 Requirements.5 - 99.5 %ile Male AF Pilots

UPTEntrance Requirements

UPTEntrance Requirements

"Traditional"Design Standards, 5th - 95th %ile

Air Force Pilots

"Traditional"Design Standards, 5th - 95th %ile

Air Force Pilots

5th - 95th %ile Female Pilots5th - 95th %ile Female Pilots

JPATS 1-8JPATS 1-8

Case 7

Design Goal

95% of U.S

College womenAge 22-

27

Case 7

Design Goal

95% of U.S

College womenAge 22-

27

Case 1

Spec. Reqmt., 82% of

U.S College Women Age 22-

27

Case 1

Spec. Reqmt., 82% of

U.S College Women Age 22-

27

67.5 % of U.S

College Wome

n

Age22-27

67.5 % of U.S

College Wome

n

Age22-27

39 % of U.S

College Women

Age 22-27

39 % of U.S

College Women

Age 22-27

41.0

Sitting Height - inches

USN41 in.

Sit. Ht.

JPATS Multivariate CasesJPATS Multivariate Cases

• Case 1 -- Small

• Case 2 -- Medium build, Short limbs

• Case 3 -- Medium build, Long limbs

• Case 4 -- Tall sitting height, Short limbs

• Case 5 -- Overall large

• Case 6 -- Longest limbs

• Case 7 -- Overall small

• Case 8 -- Largest torso

Thumb tip reach

Buttock knee ln

Knee height

Sitting height

16 20 24 28 32 36 40

inches

** *

* *

*

* *

**USAF 5-95 %

EXPANDED ACCOMMODATION ANALYSIS TOOL- Variables

BUTTOCK BUTTOCK KNEE LENGTHKNEE LENGTH

SITTING SITTING HEIGHTHEIGHT

EYE EYE HEIGHT HEIGHT SITTINGSITTING

THUMBTIP THUMBTIP REACHREACH

KNEE HEIGHT KNEE HEIGHT SITTINGSITTING

SHOULDER SHOULDER HEIGHT SITTINGHEIGHT SITTING

Example: JPATS Cases

Table 1: Multivariate Cases 1 - 7

Case 1 Case 2 Case 3 Case 4 Case 5 Case 6 Case 7

Thumb tip reach 27.0 27.6 33.9 29.7 35.6 36.0 26.1

Buttock-knee length 21.3 21.3 26.5 22.7 27.4 27.9 20.8

Knee-height sitting 18.7 19.1 23.3 20.6 24.7 24.8 18.1

Sitting height 32.8 35.5 34.9 38.5 40.0 38.0 31.0

Eye height sitting 28.0 30.7 30.2 33.4 35.0 32.9 26.8

Shoulder height sitting

20.6 22.7 22.6 25.2 26.9 25.0 19.5

Overall Large

Long limbs

Longest torsoLong torso/short limbs

Medium torso/long limbs

Small torso

/

short l

imbs

Overall Small

Small torso/Long limbs

GENERALLY AVERAGE7

2

6

4

1

3

8

5

Statistical portion(PCA)

Geometry portion

Expanded AccommodationAnalysis Technique

• % Accommodation of a given design• Impact of a geometry change on accommodation

• $$ estimate impact against geometry change vs accommodation achieved

…………………………………..…………….…………………………………..…………….

…………………………………..…………….…………………………………..…………….

…………………………………..…………….

…………………………………..…………….…………………………………..…………….…………………………………..…………….

…………………………………..…………….…………………………………..…………….…………………………………..…………….

…………………………………..…………….

• Various Populations• Combined Populations• Defined Requirements

• New design• Re-design• Competitor evaluation

.. .

. ..

.

Rapid Prototyping

Now Allows

EXPANDED ACCOMMODATION ANALYSIS TOOL- Data Analysis

MULTIVARIATE ACCOMMODATION METHOD (PRINCIPAL COMPONENT ANALYSIS)

• REDUCES A LIST OF VARIABLES TO A SMALL MANAGEABLE NUMBER

• ENABLES DESIGNERS TO SELECT DESIRED PERCENTAGE LEVEL OF A POPULATION TO BE ACCOMMODATED

• PERCENTAGE LEVEL TAKES INTO ACCOUNT NOT ONLY SIZE DIFFERENCES BUT PROPORTIONAL VARIABILITY AS WELL

• INDICATES WHICH VARIABLE PROVIDES MOST ACCOMMODATION

Bottomline: Determines % population bounded by the requirements

Principal Component Analysis--What is it?

PCA- Statistical Multi-variate analysis approach that simultaneously converts large sets of multi-dimension data into 2D or 3D linear principal components

How is this accomplished•Compute variance - Square of deviations•Compute Covariance - Product sums/Product of variances

- Correlation matrix between variables•Compute Eigenvalues- Similar to regression--goodness of fit

-Contribution of each data set variable (indication of percentage ofvariance of data)

•Compute Eigenvectors - Indicates weights of each variable in transformation - Each eiganvalue corresponds to a set of eiganvectors - Vectors position values

•Compute Principal Component - First component corresponds to with highest eiganvalue - Second component corresponds to the next highest value

…... Component 1

Com

pone

nt 2

(Subject representation)

•Component is a linear combination of original data set which accounts for most of sample variation

*Very effective in analyzing variability of human body anthropometrics

• PC based

• User friendly, rapid response

• Variable seat/cockpit geometry

• Direct manikin selection (single, multiple)

• Zone 1 and 2 reach to individual controls

• Miss distance calculation, Interference assessment

• Head clearance

• Rudder pedal reach

• Population percentage accommodation analysis

• Male, Female or Male and Female populations

General Capabilities - Cockpit Module

• Direct geometry input (make new or modify any geometry)• Direct seat/motion input (standard or variable)• Instant picture re-draw• No need for complex file transfers

• 1-7 JPATS • plus #8 JSF• plus 1 additional

Manikin Anthropometry

• Based on JPATS Manikin Anthropometry

female

male

male/female

Analysis of population accommodation

Principal Component Analysis

Direct calculationof PercentAccommodated

• 3-D Component Analysis• Subject Exclusion

Additional Analysis Capabilities

• Completing program with Tennessee State University

• Additional capabilities/modules being added

• Initial validation complete

• Validation appears to be well within 1 Standard Error from actual physical measurements

Current Status

Canopy Jetison zone 2

0

1

2

3

4

5

6

7

8

54 56 58 60 62 64 66 68 70 72

Span

Mis

s di

stan

ce Data

Model

Linear (Data)

Comboleg vs rudder miss

-4

-3

-2

-1

0

1

2

36 38 40 42 44 46

Comboleg

Mis

s fu

ll r

ud

der

/fu

ll b

rake

Series1

Series2

Linear (Series1)

Now the fun is over

Here is the homework

Oh yea, I get to leave town

• Problem 1.• This problem illustrates

developing a design with large latitude in design options. The goal is maximum accommodation of a combined male/female population.

• Eye position either 1) Get the eye up to or along the ONV line (11-18 degrees) Zone 1 or 2) in the eye box Zone 2.

• Have full rudder travel for accommodation range.

• Zone 2 reach, 14 inches below Design Eye Position and just forward of ejection line.

• Problem 2. • This problem looks at a range of

fixed designs (do not change any geometry numbers). The goal is to rank each design for the best accommodation and estimate accommodation for 1) all male and 2) male/female populations.

• Reach points given are Zone 2 (do not change locations)

• Problem 3.• This problem looks at a design

problem that has many restrictions for possibly a specialty design.

• Manikin 4, 5, 6 and 8 must be shown to be accommodated as well as maximizing overall male/female percentage.

• Optimize and develop a design for maximum accommodation, male/female plus 4, 5, 6 and 8.

• Seat contact (8 inches) below SRP to floor and floor to canopy is 50 inches.

• Rudder travel from any horizontal SRP is 30-50 inches.

• Range of seat or ejection angle is 11-25 degrees.

• Top of head in Zone 1 is minimum of 3 inches to canopy.

• Reach point Zone 2 is now 2 inches forward of ejection line and 14 inches down from DEP.

• Problem 4.• This problem is a specialized

design with constraints associated with moving devices (rudder and seat).

• Maximum linear rudder travel plus (+) maximum linear seat travel totals 12 inches or less.

• Must reach in Zone 2 a point 14 inches down from DEP and forward of ejection line

• SRP to floor under seat is 8 inches minimum.

• Goal is maximum accommodation.

• Notes:• All reaches for the model in Zone 1 and Zone 2 are a “Functional reach”, i.e., pinch.• Canopy clearance is 3 inches minimum from Zone 1 posture (top of head to inside mold line).• SRP to Floor is a minimum of 8 inches (estimates kit/seat thickness).• Ejection clearance is 28 inches or greater.• For eye position either 1) Get the eye to the ONV line (11-18 degrees) Zone 1 or 2) in the eye box

Zone 2.• Rudder accommodation (manikin foot just touching rudder circle).• Do not exceed 5 degree delta between back angle and ejection angle.• Shin contact radius min. 2 inches.

• Model notes– You have to change manikin sizes from geometry screen, then select them from

Boundaries/Others/browse menu – When you change manikin do it proportionally …torso (eye ht, sit ht, shl ht), same for butt

knee and knee ht. – Might crash if too many manikins on screen and you change zone 1 or 2 – Only edit the MODE 1, 2, 3 manikins for problems– Up and forward seat adjust is for 30 deg is 330, back 15 is 15 – DO NOT…DO NOT edit or change any link equations– Help screen gives general methods for making everything run– If it locks up or manikin positions itself funny….close and re-open it.

• Problem 1.• This problem illustrates

developing a design with large latitude in design options. The goal is maximum accommodation of a combined male/female population.

• Eye position either 1) Get the eye up to or along the ONV line (11-18 degrees) Zone 1 or 2) in the eye box Zone 2.

• Have full rudder travel for accommodation range.

• Zone 2 reach, 14 inches below Design Eye Position and just forward of ejection line.

• Problem 2. • This problem looks at a range of fixed designs (do

not change any geometry numbers). The goal is to rank each design for the best accommodation and estimate accommodation for 1) all male and 2) male/female populations.

• Reach points given are Zone 2 (do not change locations)

• Problem 3.• This problem looks at a design problem

that has many restrictions for possibly a specialty design.

• Manikin 4, 5, 6 and 8 must be shown to be accommodated as well as maximizing overall male/female percentage.

• Optimize and develop a design for maximum accommodation, male/female plus 4, 5, 6 and 8.

• Seat contact (8 inches) below SRP to floor and floor to canopy is 50 inches.

• Rudder travel from any horizontal SRP is 30-50 inches.

• Range of seat or ejection angle is 11-25 degrees.

• Top of head in Zone 1 is minimum of 3 inches to canopy.

• Reach point Zone 2 is now 2 inches forward of ejection line and 14 inches down from DEP.

• Problem 4.• This problem is a specialized design

with constraints associated with moving devices (rudder and seat).

• Maximum linear rudder travel plus (+) maximum linear seat travel totals 12 inches or less.

• Must reach in Zone 2 a point 14 inches down from DEP and forward of ejection line

• SRP to floor under seat is 8 inches minimum.

• Goal is maximum accommodation.