Virtual Prototyping and Analysis

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Virtual Prototyping and Analysis Ed
Winkler Technical Fellow Human Systems Boeing
Phantom Works St. Louis
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Percentiles
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Progression of Accommodation Expansion
F-22 (1-99)
JSF (JPATS)
F/A-18 (3-98)
Male / Female
F-15 (5-95)
Male only
60s 70s 80s
90s
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Background Current Accommodation Problems
(AFI 48-123 64 to 77 Standing height and
34 to 40 Sitting Height.)
Ref Dr. Zehner
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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
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Percentiles Are Not Additive
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 SIZE3235
From Robinette and McConville 1982
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Percentile Fallacy
If 5th to 95th percentile limits are applied to
each of the following
Remaining Percentage
95-100
0-5
Sitting Ht.
90
Butt-Knee Lth
82
Knee Ht. Sit.
78
Shoulder Brth
71
Functional Reach
67
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Average is Different From Everyone!
x y z 2 3 1 1 2 3 3 1
2
Average
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Subject 1
Subject 1
Subject 2
2
Subject 3
Subject 2
2
2 2 2
Average
Subject 3

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

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Boundary Points and Principal Components (JPATS
Cases)
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S E C O N D C O M P O N E N T
5
2
1
6
7
8
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FIRST COMPONENT
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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

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

A 10 segment CAESAR subject standing pose.
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Can Use 3-D Scans to Characterize Cases
Advantage

• With 3-D Have a Model so Can Have Set of 3-D
  Cases
• Can Visualize Real People As a Reference During
  Design

Issues and Challenges

• 3-D Shape or Size Statistics are Limited
• To Select Cases Still Limited to Traditional
  Measurements

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Distributed Cases
3
6
9
1
4
5
7
8
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Issues 1) How to Select Measurements 2) Where
to Select Cases
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Characterizing Populations
HGU 55/P Helmet
Center of Gravity Distribution
Left Pupil Distribution
Right Pupil Distribution
Right Ear Distribution
Challenge Full Population Data is Difficult to
Visualize
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Background Small Subject ( 5- 0) in the
T-38Inertial reels locked
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Stature and Sitting Height Are Not Enough

Eye Height
Arm Span
Buttock-Knee Length
Shoulder Height
Knee Height
Sitting Height
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T-1 Results VisionMinimum Eye Height 29.6

• Original design eye line -10 deg.
• Base of windscreen wiper
• Verified through study flights as minimum for
  no-flap landing

91 96 47 91
Percent Accommodated
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T-38 Results RuddersMinimum Leg Length 43
Requirement Full rudder and full brake at the
same time

• To recover from a blown tire on landing
• Pilot tightly restrained

Percent Accommodated
95 97 46 81
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EXPANDED ACCOMMODATION
5-95 PERCENTILE DESIGN POPULATION WITH JPATS
OVERLAY COMPARISON.
COMBINED ACCOMMODATION
55
50
Approx. 5-95 MALE USAF Range
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LEG LENGTH (in.)
40
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- JPATS Manikins
35
45
40
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SITTING HT. (in.l)
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Accommodation Limits
JPATS 1-8
F-22 Requirements .5 - 99.5 ile Male AF Pilots
Case 7 Design Goal 95 of U.S College
women Age 22-27
Case 1 Spec. Reqmt., 82 of U.S College Women
Age 22-27
UPT Entrance Requirements
67.5 of U.S College Women Age 22-27
USN 41 in. Sit. Ht.
39 of U.S College Women Age 22-27
"Traditional" Design Standards, 5th - 95th
ile Air Force Pilots
5th - 95th ile Female Pilots
31.0
32.0
33.0
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
Sitting Height - inches
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JPATS 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










USAF 5-95
16 20 24 28 32 36 40
inches
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EXPANDED ACCOMMODATION ANALYSIS TOOL- Variables

SITTING HEIGHT
EYE HEIGHT SITTING
THUMBTIP REACH
KNEE HEIGHT SITTING
BUTTOCK KNEE LENGTH
SHOULDER HEIGHT SITTING
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Example JPATS Cases
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4
Long torso/short limbs
Small torso/ short limbs
Longest torso
8
2
1
Overall Small
Overall Large
5
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GENERALLY AVERAGE
Small torso/ Long limbs
Long limbs
Medium torso/long limbs
6
3
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.. .
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Statistical portion (PCA)
Geometry portion
Rapid Prototyping

• Various Populations
• Combined Populations
• Defined Requirements

• New design
• Re-design
• Competitor evaluation

Expanded Accommodation Analysis Technique

• Accommodation
• of a given design
• Impact of a geometry change
• on accommodation
• estimate impact against geometry change
• vs accommodation achieved

Now Allows
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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
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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 of
• variance 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 is a linear combination of
• original data set which accounts for
• most of sample variation

Very effective in analyzing variability of
human body anthropometrics
(Subject representation)
Component 2
...
Component 1
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General Capabilities - Cockpit Module

• 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

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• 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

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Manikin Anthropometry

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

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• Based on JPATS Manikin Anthropometry

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Analysis of population accommodation
male
Direct calculation of Percent Accommodated
male/female
Principal Component Analysis
female
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Additional Analysis Capabilities

• 3-D Component Analysis
• Subject Exclusion

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Current Status

• 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

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Validation
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Now the fun is over Here is the homework Oh
yea, I get to leave town
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• 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.

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• 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)

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• 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.

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• 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.

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• 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/br
  owse 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 NOTDO 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.

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Demo Teams Questions
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• 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 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 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 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.