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Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
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OCR for page 43
4
Human-Machine Interface Models
Information generated by anthropometric and dynamic biome-
chanical modem is needed to build the next level of model in the
hierarchical structure, that is, the interface model. Interface mod-
els describe the interactions among the anthropometric and the
biomechanical modem in a symbiotic relationship with the equip-
ment used in system operation.
Typical applications of these quantitative anthropometric and
biomechanical modem are their use in the development of inter-
face modem as COMBIMAN (computerized biomechanical man
model), CAPE (computerized accommodated percentage evalua-
tion), CAR (crewstation assemment of reach), SAMMIE (system
for aiding man-machine interaction evaluation), CREW CHIEF
(computer-aided design mode} of an aircraft maintenance tech-
nician), and PLAI~TEMPUS (three-dimensional mode} of an
interactive environment for the design and evaluation of system
design and operation). Each of these interface models relies on an-
thropometric and biomechanical data to mode} the relationships
among people, tasks, equipment, and the workplace.
Early approaches to the development of interface models and
their characteristics are shown in Table 4~1 (Kroemer, 1973~. In
1967, Popdirnitrov (Popdirnitrov et al., 1969) reported on one of
the first interface models, BULGAR, which was used for calcu-
lating the positions of certain parts of the body related to a per-
son's posture. Other approaches, such as DYNASTICK (Wartiuft,
43
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OCR for page 45
45
1971) and TORQUE MAN, LIFT MAN, and FORCE MAN (Chaf-
fin, 1969), were based on linkjoint Stick man modeled they repre-
sented mass properties and capabilities for exerting forces. MTM
MAN (Kilpatrick, 1970) incorporated elementary motion times
from tables used by industrial engineers. The ARM MODEL (Ay-
oub, 1971) simulated two-link arm movements, using power as
an optimization algorithm. CINCT KID (Huston and Passerello,
1971) incorporated kinematic and kinetic aspects of the human
body and the effects of gravity. BOEMAN (Boeing Company,
1970; Ryan, 1971) was a complex mode! of a pilot sitting in an
aircraft cockpit. This mode} was intended for use in the evaluation
of the geometry of aircraft cockpits with respect to their suitability
for the aviator. COMBIMAN (Krause and Bogner, 1987; Kroe-
mer, 1973; McDaniel, 1976) was developed based largely on the
experience of the Boeing Company, hence it has been called "son
of BOEMAN."
Since 1973, several other interface modem have been devel-
oped. They include CAR (Edwards, 1976), CAPE (Bittner, 1975),
ATE (Fleck and Butler, 1975; Butler and Fleck, 1980), PLAID-
TEMPUS (Lewis 1979 a, b) and, currently under development,
CREW CHIEF (Korea and McDaniel, 1985~. These modem and
their interrelationships are discussed In the following text.
BOEMAN
BOEMAN is a computer-based mode} that was developed
for the design and evaluation of cockpit and other crewstations
(Ryan, 1970, 1971~. Although it provided a broad conceptual
framework for the study of diverse variables, its prunary reason for
development was aimed at the assessment of the seated operator's
ability to move toward and reach controls.
The operator model is made up of a system of 31 links that are
constrained by hard angular Innits at each body joint. In addition,
a time-cost function is associated with each joint. Mathematical
programing is used to minimize the total time as the operator
reaches from one point to another.
The links are typically enfleshed by truncated cones. Cockpit
boundary surfaces are defined. Model reaches are made within
the boundaries imposed by enfleshment and cockpit surfaces. The
result of exercising the mode! is a description of the effort and time
required to reach the controls and provides indications of the points
OCR for page 46
46
of contact between limbs and cockpit surfaces. This mode! has
proven complicated to implement because of the volume of data
required and the complexity of the cost of movement algorithms.
Consequently, it was typically employed late in the design process.
BOEMAN provided the conceptual bases and motivation for
other workplace assessment models, for example, CAPE, CAR,
and COMBIMAN.
COMPUTERIZED ACCOMMODATED PERCENTAGE
EVALUATION (CAPE) MODEL
The CAPE mode! was developed as a design too! for the as-
sessment of cockpit crewstation design in terms of the percentage
of the aircrew population that could be accommodated by that
design (Bittner, 1975, 1979~. The CAPE program used a multi-
variate Monte CarIo simulation to create a typical sample, based
on 2,500 "pilots" that matched the means, standard deviations,
and correlations of 13 anthropometric variables that are critical for
the design of cockpits, that must fit a target population (Gifford et
al., 1965~. The Monte Cario simulation component of this model
was tested in a series of investigations that compared actual and
Monte CarIo estimates of the proportion of a population accornmm
dated as various anthropometric exclusions were applied (Bittner,
1974~. The Monte CarIo component was found to be valid based
on the results of four evaluation studies (Bittner, 1976~.
The CAPE pilot link system component was selected to aug-
ment arm and leg reach models in the design standard for military
aircraft (Department of Defense, 1969~. This link system was
viewed only as a baseline; the development of a later model based
on the BOEMAN (Ryan, 1970, 1971) link system was proposed
(Bittner and Moroney, 1975~. This proposal was implemented
subsequently in the CAR mode] (Edwards, 1976; Harris et al.,
1980), which replaced CAPE.
CREWSTATION ASSESSMENT OF REACH (CAR) MODEL
The CAR model is a design evaluation too! for determining the
population percentage that can be accommodated by a particular
crewstation design (Edwards, 1976; Harris and lavecchia, 1984;
Harris et al., 1980~.
The CAR mode! allows the user to define the geometry of
OCR for page 47
47
the crewstation and to select an operator sample to evaluate the
crewstation design. The CAR mode! consists of an anchorage
point, the design eye point (DEP), the line of sight (LOS), seat
characteristics, head clearance data, and a set of hand and/or foot
controls. The anchorage point is the fixed location in space to
which the operator must position a specific body part. Anchorage
options include:
seated, positioned to DEP (similar to BOEMAN);
seated, positioned to a foot control;
seated in a nonadjustable seat;
standing in a fixed position;
shoulder positioning; and
hip positioning.
The operator's seat consists of a seat back, seat pan, seat
adjustment, and harness. The seat adjustment is defined by the
seat reference point (i.e., the center of the line segment formed by
the intersection of the seat back and the seat pan), the furthest-
down forward position of the seat, and the furthest-upward back
position of the seat. The user defines the harness by specifying
the position along the horizontal shoulder line where the harness
meets the shouicler. A maximum of 50 controls can be specified for
the crewstation. Controls are defined in terms of body part (hand
or foot), the grip that is appropriate for the control (clenched
palm open; fingertip; thumb; or pinch, extended, or point), the
harness condition flocked or unIocked), and the control location.
An additional point representing the lining of the linear range of
movement is specified for adjustable controls.
The sample population can be generated either by a Monte
Cario process based on the means, standard deviations, and corre-
ration coefficients of standard anthropometric measurements fol-
lowing the procedure developed by Bittner (1975) or by using
direct inputs based on the actual measurements of test individu-
alm. In either case, body measurements for the sample population
are transformed into links, a modification of the procedure used
in BOEMAN (Ryan, 1970, 1971~. The 19 links in the CAR link-
person mode! (Figure 4-1) represent a simplification of the human
skeletal structure from the 31 links used for BOEMAN (Harris
and lavecchia, 1984; Harris, et al., 1980; Zachary, 1979~.
The CAR mode] analyzes the ability of an operator in the
sample to reach a control by starting at the lumbar joint and
OCR for page 48
48
1a
;~12 t3)
1—LUMBAR
2—THORAC1C
3—NECK (VERTICAL)
~—N ECK ( HOR I ZONTA L)
5—HEAD (LOWERS
6_ EYE
7—HEAD IUPPER}
—l~TERCLAVt6VLAR
9—CLAVICULAR
10—HUM£RAL
1 1—RAOIA'
12—HAND (CL£NCHED,
13—HAND I F INGE RTIP OR IP'
14—HAND (EXTENDED'
15—PELVIC
16—fEMORAL
17—IlBIAL
18—ANKLE
19 - FOOT
FIGURE 4-1 CAR Link-person model. SOURCE: Harris and Iavecchia
(1984~.
adding links in succession in the direction of that control. The
links are constrained by angular limits of motion associated with
each link joint, the harness conditions, and the type of clothing.
Since the link lengths calculated for the operator sample are for
an unclad operator, CAR allows the user to specify whether the
operator Is wearing either summer or winter flight clothing. The
clothing specification modifies the appropriate link lengths and
the angular limits of motion.
Three types of reaches can be incorporated into the CAR
model:
Zone 1: The shoulder harness is locked, and the operator does
OCR for page 49
49
not strain against the harness. The lumbar, thoracic, interciavic-
ular, and ciavicular links are immobile. The remaining links are
aBowed to move within their angular lignite.
Zone 2: The shoulder harness is locked, and the operator
strains against the harness. The lumbar, thoracic, and interciav-
icular links are i~runobile. The cIavicular link ~ aDowed to move
within the confines of the harness. The remaining links are allowed
to move within their angular limits.
Zone 8: The shoulder harness is unlocked. AD links are
aBowed to move within the bounds of their angular limits. Zone ~
and zone 2 reaches are performed for all hand controls, where the
shoulder harness is specified as locked by the user. Zone 3 reach is
performed for foot controls and hand controls, where the shoulder
harness is specified as unlocked.
CAR evaluates each operator in the sample to determine the
ability to place himself adequately (i.e., with respect to anchorage
point, DEP, LOS, and head clearance) and the ability to reach
controls for zones 1, 2, and/or 3 reach as appropriate.
The results indicate the percentage of the population that can
achieve visual accommodation and the percentage that is capable
of reaching each control. Guidance in changing control positions
for improved accommodation ~ given in the form of reports de-
ta~ling the distance and direction of control location alteration to
accommodate additional portions of the population.
The flexibility of a mode} such as CAR was illustrated in a
recent program for flight deck design (Stone and McCauley, 1984~.
In that study, data input was based on the anthropometric mea-
surement of a broad range of aviation personnel in the U.S. Air
Force, Army, and Navy. Stone and McCauley observed that, using
the standard numerical link-person analysis provided by CAR, an
accurate analysm of reach could be performed. Complete fit and
function analyses required both graphic output and enfleshment
(Figure 4~2~. The resulting figures are three-dimensional and pos-
sess the dimensional characteristics of the people created by the
CAR program in terms of both link and body dimensions.
For flight deck design, the CAR mode! generates full reach en-
velopes in various planes, along with eye and seat reference point
locations. All the components are then integrated to allow evalua-
tion of alternative designs for placement of controls, displays, and
other equipment as a function of operational task requirements.
OCR for page 50
so
,7~
FIGURE 4-2 CAR three-dimensional anthropometrically variable crew
member. SOURCE: Stone and McCauley (1984: 113. Reprinted with
permission ~ 1984 Society of Automotive Engineers, Inc.
The resulting three-~nnensional models of the operator, the
equipment, and the environment can be viewed on the screen
in front, top, and side elevations; in isometric projection; or in
perspective from any viewpoint. This capability enables the user
to enter and walk around inside the model.
The scale of the model can be changed and hidden lines can
be removed. All objects within the mode} can be repositioned and
regrouped. Further development of the CAR mode! will provide
OCR for page 51
51
a building block concept for systematic design and evaluation of
various workstations.
Efforts are under way to validate the CAR model. For exam-
ple, based on the CAPE mode} (Bittner, 1975), the Monte CarIo
component has been evaluated by four accommodation studies,
which have been summarized by Bittner (1976~. In addition, the
anthropometric measurements and reach envelopes for individual
subjects are being directly compared with mode] estimates under
typical seat, restraint, and workplace conditions. Finally, CAR
has been tested for the congruence of mode} reach data and exper-
imentally derived anthropometric reach envelopes (Bennett et al.,
1982; Kennedy, 1978~.
SYSTEM FOR AIDING MAN-MACEINE INTERACTION
EVALUATION (SAMMIE)
SAMMIE, developed by a team of investigators at the Uni-
versity of Nottingham, EnglancI, under the leadership of Maurice
Bonney, was produced to evaluate the design of simple workstation
layouts (Bonney et al., 1969~. With SAMMIE three-dimensional
models of equipment ant} environments can be built by specifying
and assembling geometrical shapes. The anthropometric mode! is
preprogrammed to represent a male of average height and weight
based on data developed by Dempster (1955), but can be modified
to represent other anthropometric data.
SAMMIE consists of two independent modules:
~ Three-dimenmonal modeling functions: This component
builds models of equipment or workplaces by assembling primitive
geometric shapes or general shape definitions, as shown in Figure
4-3.
Man-model: The human mode] consists of 19 connected
links representing a schematic skeleton around which three-dimen-
sional solids such as boxes, cones, and cylinders are placed to
denote outer contours of the human body.
The idealized flesh contours can be varied to simulate body
builds from stern to rotund (Sheldon, 1940~. Each link length can
be varied to create different body proportions and can be adjusted
to any feasible body position. Extreme limits of joint movements
and comfort can be included in the model. The body segments
are connected by pin joints at the shoulders, hips, neck, knees,
.
OCR for page 52
52
~1
~'4
\\W
\
/
FIGURE 4-3 Example of a SAMMIE geometrical model. SOURCE: SAM-
MIE Human Factors 3-D Design System (1985~.
and other articulations. Logical relationships are included so that
when an upper arm moves, the lower arm and wrist also move in
the expected direction, representing normal human movement, an
specified in a user-definable joint constraints table. The limbs can
only extend as far as human limbs can reach. It is also possible to
mode! factors that limit movement, such as clothing.
SAMMIE has the capability to create concave, convex, or
plane mirrors superimposed on any surface in the workplace and
can then examine the reflections found from any vantage point.
Another module is used to assess visibility encompassing 360 de-
grees of view horizontally and 180 degrees vertically.
The following evaluations can be performed by SAMMIE:
ability to reach;
fit of a person in a confined workspace, including oper-
ator size an] shapes, clearances, and access aperture sizes and
positions;
.
working postures (e.g., seated, standing, bending);
. visibility, including head and eye movement constraint,
production of two-dimensional vision maps, and three-dimensional
vision charts;
field of vision;
blind spots; and
OCR for page 53
53
· —
~ mirror views.
The environmental component of SAMMIE consists of geo-
metrical information defining solid objects, location and orienta-
tion data, and relationships between objects and humans.
The mode! can be viewed in plane parallel projection or in
perspective (from either outside or within the model) in front, top,
and side elevations or a combination of views. The mode! can be
viewed from a specific internal center of interest or from a position
that represents the subject's visual view of the environment. The
scale clan be changed and hidden lines can be removed.
The model, once constructed, can be repositioned and re-
grouped as needed. It lends itself to the modeling of human inter-
actions with control panels and workplace ergonomic evaluations.
Movement can be simulated frame by frame to evalute reach, fit,
strength, balance, comfort, or vision for candidate postures.
ARTICULAT1:D TOTAL BODY (ATB) MODEL
The ATB mode] is a modified version of the crash victim simu-
lator program developed by Cal~pan Corporation for the National
Highway Traffic Safety Administration (NHTSA) to study human
response during automobile crashes (Fleck et al., 1975~. The U.S.
Air Force's Armstrong Aerospace Medical Research Laboratory
modified this mode} for application to the study of human body
dynamics during ejection from high-performance aircraft, devel-
oped a three-dimensional projected graphics display capability,
and applied the name articulated total body (ATB) mode! to this
modified software program (Butler and Fleck, 1980; Butler et al.,
1983; Fleck and Butler, 1975~.
The three-dimensional ATB mode} is formulated in terms of
rigid body equations of motion. The body segments do not deform
during motion; all body deformation occurs only at the joints that
connect the body segments. The standard configuration consists
of 15 segments, but the actual number that can be specified is
limited only by the computer memory.
The body segments are coupled at joints, the centers of which
are specified by three-dimensional coordinates within each segment
and with respect to landmarks on that segment. Each segment has
its own coordinate system defined with respect to bony anatomical
landmarks on that segment. Coordinate systems are also defined
OCR for page 57
57
two-dimensional display, two orthogonal views are projected si-
multaneously and can be rotated for viewing at any angle and can
be magnified. In the model, however, alogrithms exist in three
· -
.lmenslons.
The evaluation techniques consist of defining the dimensions
of the man-mode! and simulating intended tasks within the work-
place.
The man-mode} dimensions can be defined in several ways:
. Direct Measure: Specific measurements are entered from
the keyboard or punched cards.
. Data Base Summary Statistics: Percentiles computed from
large samples are used to define the man-model. Individual seg-
ments may be modeled for groups with different percentiles.
~ User Population: Several anthropometric surveys are in-
corporated in the COMBIMAN model. A utility program allows
the user to define which survey to use or to add data from other
surveys.
Computer-Aided Dimensioning: Abstract human models
can be generated from anthropometric survey data. A critical
body characteristic relevant to the evaluation of a task can be
called up and used to construct a proportioned man-mode! based
on a series of regression equations.
Once the man-mode] is built, it can be positioned by com-
mands from a light pen or keyboard.
The COMBIMAN hand is made up of three links originating
from the wrist: (1) grip center (for whole-hand grasp); (2) func-
tional reach (e.g., finger grip, knobs); and (3) fingertip reach (e.g.,
pushing a button).
The program evaluates reach capability as a function of cloth-
ing and restraints (harness) in two ways. First, the user can select
a control handle or pedal, or even an arbitrary point in space, and
the COMBIMAN simulates the process of reaching to that point.
Second, the user can select a control panel, and the mode} will
compute the maximum reach envelope in the plane of that panel.
If a point or control can be reached, the user can evaluate the
force which the COMBIMAN can exert in that control location,
in a defined direction, and to a specific control.
The reach routine applies to the arms, legs, and head. Move-
ments can be limited or confined, such as arm-shoulder movement
only or arm-shoulder-trunk movement.
OCR for page 58
58
A printout and plot of the workplace providing detailed body
dimensions of the man-model and coordinates of the workplace in
any scale can be generated at any design or evaluation stage.
For mapping the visual field of a workplace, COMBIMAN
defines a range of three-dimensional head and eye positions with
coordinates. The size of the operator, seat adjustment, head pm
sition, and visual restrictions can all be varied. This generates
realistic visual angles.
Other features of the COMBIMAN include the following:
.
· Change View: Views the model and crewstation from any
angle.
Identify Object: Shows the name and three-dimensional
coordinates of any characteristic of the crewstation.
Omit Object: Declutters the display.
. Retrieve Cremation: Calls up any of the crewstations
stored in the library.
· Visibility Plot: Plots the crewstation as seen by COMBl-
MAN.
· Display Anthropometry: Displays the values of sizes of the
body segments.
· Display Links: Displays the dimensions and angles of the
skeletal link system of COMBIMAN.
· Design Panel: Allows the user to add a new characteristic
of modification to an existing crewstation.
Modify Posture: Permits the user to manually change the
posture of the model.
· Seat Adjust: Allows the user to reposition the seat.
· Zoom: Causes a portion of the image to be magnified to
fill the entire screen.
· Plot: Produces paper a plot of the crewstation and COM-
BIMAN in any scale.
· Add Crewstation: A utility program that allows a user to
define a new crewstation and add it to the library.
CREW CHIE1?
The U.S. Air Force Armstrong Aerospace Medical Research
Laboratory and the U.S. Air Force Human Resources Laboratory
are jointly developing a computer-aided design (CAD) model of an
aircraft maintenance technician (McDaniel, 1985; McDaniel and
OCR for page 59
59
Askren, 1985~. This three-dimensional interactive graphics mode]
would have an interface with existing commercial CAD systems.
The developers expect to have an initial version available for use
in 1988.
The CREW CHIEF model will give the CAD designer the
ability to use the computer drawing board to simulate mainte-
nance and related human operator interactions with a system.
It will represent the correct body size and proportions of the
maintenance technician, the encumbrance of clothing and personal
protective equipment, mobility limitations for simulating working
postures, physical access for reaching into confined areas (with
hands, tools, and objects), visual access (seeing around obstruc-
tions), and strength capability (for using hand tools and manual
materiab-handling tasks).
The CREW CHIEF mode! user will be able to select data
from a range of body sizes of both male and female maintenance
technicians.
The initial mode! will have four types of standard clothing to
choose from: fatigues, cold weather, arctic, and chemical defense.
The clothing interacts with the joint mobility limits for strength
and posture to mode] accessibility.
The CREW CHIEF mode} will display the visual accessibility
of maintenance personnel. For example, inserting a screwdriver
into a screw head requires that the technician simultaneously see
and reach the screw head. The CREW CHIEF mode} allows the
designer to see the task from the maintenance technician's view-
point and to determine whether it can be physically accomplished.
The 12 CREW CHIEF mode! postures include standing, sit-
ting, kneeling on one knee, kneeling on both knees, stooping,
squatting, prone, supine, lying on the side, walking, crawling, and
climbing. Some of these postures reduce the mobility of the limbs
and the strength available to perform the task. These are only
starting postures, however, and the designer can manipulate all
the body segments as required to achieve the desired posture.
Posturing will be automated for accessibility, reach, and strength
analyses.
The CREW CHIEF mode! will have a realistic simulation of
the strength capabilities of a maintenance technician. AAMRL
has recently gathered strength data relative to the manual han-
dling task (lifting, pushing, and pulling) for the postures described
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60
above. Another major data base includes torque strength with var-
ious hand tools.
The CREW CHIEF model itself will be three-dimensional. To
accurately represent the clothing, the mode! will have a surface
of facets (triangles) attached to the 35 links which make up the
skeletal link system. A simplifier! three-dimensional mode! will be
available whenever the designer wishes to rotate the model, and
a hidden line two-dimensional mode! will be available for high-
resolution views and plots.
PLAID AND TEMPUS
PLAID and TEMPUS are modeling programs created specif-
ically for the Man-Systems Division, Lyndon B. Johnson Space
Center (]SC), National Aeronautics and Space Administration, for
use in man-machine interface design and evaluation for the space
shuttle and the initial space station configuration. The earliest
concept of PLAID was an interactive graphics software system for
the design of instrumentation pane} layouts (Lewis, 1979a; PLAID
Preliminary Specifications, 1977~. PLAID is currently housed in
a VAX 11/785 computer. PLAID will also be used with an auto-
mated anthropometric measurement system being developed for
DISC (Lewis, 1979b).
PLAID is a system for analyzing the crew interaction with
crewstations and spacecraft systems and components (Brown,
1982~. It is based on full-scale, three-dimensional, solid-geometry
computer software models that are created interactively by the
user. The program can represent humans in shirtsleeves and spacer
suits, crew workstations, spacecraft, and virtually any structure
the user desires to build. These elements, called primitives, are
assembled in the computer and viewed on the computer moni-
tor. PI,AID provides flexibility in achieving the desired renderings
and evaluation products, while the mode! data base stores created
primitives and assemblies for subsequent use (Brown, 1981~.
The user begins the modeling process by defining the end
product. If a primitive that is required for the activity is in the
data base, the user can assess its appropriateness for the particular
analysis.
All primitives are constructed in BUILD, the first major mod-
ule of PLAID, from planar polygons created interactively by the
user. The polygon can be built either graphically or numerically in
OCR for page 61
61
one of six standard orthographic views (front, back, top, bottom,
left, or right). Once polygons are created, the user can combine
them, either by translation along one, two, or three axes or by
rotation about some axis. Hence, a square can be translated along
the nonrepresented axis for conversion to a rectangular box, a
hal£circIe can be rotated about its base to create a sphere; and a
circle can be rotated about an offset axis to form a torus.
A contour function allows the creation of a solid object by
joining planar polygons, essentially creating a surface between
the edges of two planes. This function is particularly useful for
building objects with complex contours, such as the human body,
human reach envelopes, and the space shuttle orbiter. For exam-
ple, by using cross-sectional plots (reduced from digitized body
mapping data in PLAID's REACH module), a shirtsleeved crew
member can be created graphically.
A second major module of PLAID, COG (composite object
generator), ~ the basis for grouping constructed prirn~tives. The
COG file contains primitive parts, COG file (subassembly) parts,
or some combinations of primitives and subassemblies. Versatility
can be achieved by careful selection of parts and by the COG file
structure itself. The use of subassemblies facilitates stop-action
articulation or motion in assembly since a subassembly has both
its own local coordinate system and a second one in a global
coordinate system of the assembly achieved via translation and
rotation. By layering subassemblies and parts, a human arm, for
example, can attach to the shoulder, yet when rotated, the upper
arm primitive and lower arm subassembly move as a unit. At the
next level, the lower arm, attached at the elbow, moves itself (a
primitive) and the hand assembly attached at the wrist. Each
element of the arm has its own local origin and coordinate system
to enhance motion commands but can be translated and rotated
to attach it to the next element in the tree.
Final viewing and conflict checking is performed with a third
major PLAID module, DISPLAY. Here, the user identifies the oh
ject (i.e., target file) of interest and specifies the other parameters
that are required to produce the desired end product.
Several alternatives for the final renderings are available, in-
cluding a wire frame, in which all assembly lines are visible. This
common-form rendition is often satisfactory for simple objects, but
interpretation usually suffers from ambiguity. In another rendi-
tion, hidden lines are automatically removed or shown as dashed if
OCR for page 62
62
behind-the-scene viewing is required. A conflict detector is another
user option in which collisions of parts are defined numerically and
graphically for ready identification. The PLAID program also cal-
culates between-vertex clearance. While these line drawings are
appropriate for most applications, PLAID shaded renderings are
also available.
The REACH module of PLAID serves as the interface with
the anthropometric data to render crew reach and body mapping
contours and contours from other digitized data.
By using PLAID for interface ergonomic models, human body
models of various sizes can be built and articulated with respect
to workstation layouts. Improvements are sought, however, in the
complementary software package TEMPUS to create a basic man-
mode! that will interact with the PLAID program and data base
elements. The TEMPUS user interfaces allow for a user-specified
body to be constructed and more easily manipulated in the desired
environment. For example, the PLAID person is articulated by
the user on a joint-byjoint basis, with the user being responsible
for body size parameters and joint limits. In TEMPOS, the user
selects a specific crew member from the data base, one or more
anthropometric measurements, or a random body. The internal
anthropometric data base governs the constraints for size, range of
motion, sex, and other parameters. Thus, the computer can avoid
the use of a trial-and-error positioning schema.
The body modeling is accomplished by using the data in the
CAR mode! (Harris et al., 1980~. Following CAR, TEMPUS cal-
culates the body segments by using regression equations. These
segments are then used to build a link person. One graphic prm
cedure that provides a realistic approach is the use of Bubble
people" (BadIer et al., 1980), which are composed of hundreds
of small spheres. Enfleshment of the link is proportional to link
length; girth measurements are not used. Other graphics models
include stickmen (no thickness) and ~polybodies" built of polyhe-
drone. In each case, the three-dimensional body is generated by
the computer and displayed graphically in the workstation. (For
a detailed review of this technique, see Woolford and Lewis [1981]
and Stramier and Woolford 1982.
Knowledge of the positions of the arms, legs, head, and torso as
well as their velocities and vectors are required to specify a body in
motion. Specifications of forces requires knowledge of accelerations
as well. Data storage and access requires extensive effort, however.
OCR for page 63
63
In the initial stages of the study of the biomechanics of astronaut
extravehicular activity (EVA), a dictionary of units of motion
is constructed. The dictionary entries are isolated motions that
can be combined to describe complex tasks. For planning new
tasks, the components can be extracted from the dictionary and
combined to describe the activity. Information regarding time,
forces, restraints, and aids that are required to perform the tasks
can be deduced.
A major requirement for these modem of human performance
is realistic motion data. Some rules of motion can be extracted
from the viewing of films of human motion. However, more precise
data can be obtained by digitizing data derived from points on the
arms, legs, and torso as the subjects move. Automation can play
a large role in this regard (O'Rourke, 1980~.
TEMPUS has an associated anunation capability in which the
movements of subjects and objects in the picture can be coordi-
nated with each other and with a soundtrack. The animation Is
dependent on the operator drawing key frames in which the stages
of motion are displayed. For example, while reaching for a switch
the body might be portrayed in the rest position with the arm
partly raised and the hand on the switch. The animation facility
then generates intermediate frames between these key frames to
interpolate motion.
One approach to the analyses of changes in body position
and force vectors during the performance of a task ~ the use of
models rather than traditional tables. For example, the body can
be modeled as rigid links connected with rotary motors capable
of exerting known forces or moving at known velocities. The
kinematics and dynamics of the body can then be modeled by
using trigonometry, differential] equations, and linear algebra.
Digitized film data taken of astronauts are used to develop
models of forces applied in EVA tasks. (See Bowden [1981] for a
description of some of the pioneering efforts in this area.) This
effort results in equations of motion that can be integrated numer-
ically to provide position and orientation information for the body
segments. In turn, these data can be used to drive graphic displays
of motion to permit assessment of proposed EVA procedures.
OCR for page 64
64
DISCUSSION
Table 4-2 summarizes many of the important features of these
models. The following points describe the state of the art In the
development of interface modem.
.
Current interface models are specific to given designs, pur-
poses, or characteristics.
The usefuInem of interface modem ~ limited by the anthro-
pometric and/or biomechanical data input.
The workstation and the operator need to be accurately
modeled.
Predictive models of the effects of the dynamics of "plat-
forms~ (e.g., ships, spacecraft, airplanes) on tasks are not
available.
There is a paucity of dynamic interface models.
Effects of stress and motivation have not been adequately
quantified or modeled.
Effects of fatigue, trauma, and other injuries have not been
adequately quantified or modeled.
The effects of environmental factors on human performance
are largely unquantified.
The impact of complex aspects of vision, audition, and the
speed and accuracy of responses to other sensory inputs
and signals need to be explored for their impact on human-
machme interface modeling.
Sociological factors such as habitability that have an effect
on human performance are largely unquantified.
Mode} validation is a largely unresolved issue.
OCR for page 65
65
CONPARISON lAllE Of INlElf~£ NODElS T~le 4 - 2
IiIL ~ Of CO8~lR6t I Vt ~N l S
IIODELS 2-D
3-.
LlKl/OIHEI - 'E DY - lC/S[`rlC LIKIIS
JOINTS
S llf N6IH V1510#
cia 3 D 3i LiNiS ViRiED E*lE~Ni S;iiiC ;oi~i ~E c~sTiii~rs ~o -Ef£ REfERENCE
17 ~IE CA~O 110 - lldlS IEO~IlIC~-Y`IIOUS tOS1I10~ CIOIHI~, lEST~IKI POIHT - 9 LINE
{BlD6. llOC! SI4ULlI10N fROh PRINIII~S ~ CI=ES) SYSIEN Of SICHT
SYSTEM) Dir' - Y 1# rHE SIohE
NCCAUlEY CiD/C~I
lllERtiCE VERS
.
S - IE 3-D -1161D
-19 lill!S
. . .
-6EONErtlC~ tlIIIIlVES Sr~rlC
{CO#ES, CTllNDERS -ViRIOUS ~SITIONS
ClRClES) -C" IE SEOUEIlCEt
. ..
-lO61C~
lElilJOkSHIPS
-lr~lr~r'11
Of IIOY£11ENI
-lol~r
CONSTRAJ#T
-CLOIH1146
~0
-HEID ~ ETE
NOVENElT
COItST~IlT
-2-' fISI.
MPS
-3-D VISI.
~S
-fJ£LD Of VISI~
iI1 3-D -IS 01 "E
-IICID
-SE6NENTS
. . .
COI8ItWI
{COIIPeterit
IIOsesbeeic~l
11611-~o~1)
.
3-D -3S YARI~lE
LINIS, D£FINED
I~NUALLl OR
flO.I DAll IASE
-ElilPSOIDAl fOI -3-DJ8ENSJO"
CO#~`CIS, "' ~PE IOD! DI - ICS
fOI C~HJC~
DIS~'r
-PlK, EULEI ~
6L~061,PHIC JOJlIS
VIrH R^E Of MOTION
~D NOT10# RESISI - E
P - EIII£S
-IRIEfiULA1 3-D F`CETED -SIiIIC dITH -~l IOJ#TS - ~lE
SU8F6CE d/ "ESSElII~ ~1~! D Ll~ tE~ 81 6 DE6REES OF
ESSENTI1L lllES CiP~ILII7, ~L FREEDON. H~t'
llNES RE~YED llNIS RE - ED CLOrHIN6 ~JLIT'
110 110
~ .
-PREDJCTS 1,S,~, -PLOTS VJEU
~S "D ~TH [0 ~EdSTIT1 -
PERCEITILE "E · ~IOO DE61EES
FE~LE ST~N6TH ~I~T#.
-LI8JTS V17H ~TO - TED 1N f~"lD RE~ -~ DECtEES
LlKl RE6CN H£llSPHERE ELEY`TI~ UITH
VISIOII LIMIT
OVEILifS,
- - ILE HEAD
CREN CHiEf 3-i 3S ViRlillE -IRRE6UliR J-0 fiCETED -STiTJC dJTH -RfSTRJCTJO. Ir CLOTH 6 -PREDICTS l,S,SO, -PLOTS YlEN Of
LINIS DEfJ#ED SUlfAeCE V/ NONESSENTIAL ~Ur~AT D Ll. REACH 01 PIOTECTIVE EOUIPHT 9S ~ 99TH IT1LE BOIItL" ~1
f~l DiTt IiSE lJ#ES REMOVED CiPAtilITY, All ~IlITr llHJTtT NS ~LE I FE - E AUI - TH'
ll~lS REHOKD -RESTRJCrED REACH 11 STRENCIH f~ KA1~ -~ DE61EES
6 DE6REES Of flEEDOII TENAIICE ACTIVITIES ELEVtTION UIIH
YIS10# LIMIT
OVERLAT5
-t - ILE HE~
.
PL1ID/IEHPUS 3-D
-NUt I l-l INI
tODY HODEl
-hAN-HoDEL
SANE tS CAR
-SIICthAN
-POITtODIES/
POl THE ORONS
dlilBlE PEOPlEt
SPHERES
-6EOt~f TRIC
~ODELS-SPKRES
-3-D SUREACE
KAPPINC SYSrER
(liRS}
-lASER IASED
COORDINATES
-sT'rlc, tur
SIIIJlllES Norl0N
81 USE Of CE06
ANIBATED SEQUENCE
-~OtAI TR`NSLiT H
OR ~OIlilON Of ll~
OR tODY
.
-RON CONSTR1JNTS -COLLECT 6 DAIA -DEfIKITION Of
-CONSTRAIN! IT CLOIHIN6 -HoDELIN6 fORCES YIElI~ COOIDI - TES
fOR TtSIS - - E~ fUNCTIO!
YISUAL ~ESS
OCR for page 66
66
COCNIlIvE dORtS11IION fOIICES
APPl IED
ANIHROPO~IRIC D`Td SCALE/CHAN6l VlEV
D`ll IlSE
. . ~ . . . . .. ..
Ko -CO#1ROLS, DlspLArs No~ -'Nr POPUL'TIoll D'1' -tODr SIIE, CLOTHIN6 -rEs (Il SrONE -Allr VIEV 1#
SE`I, ~fSTRAIN! a~sE dHICH INClUKS ~S,RESTRICTIONS, CRfB- AND HccAuEr STONf. A#D acc~LEr VERS10N
SrSTE' Sl~llD`RD DEVIllIONS, AIID sr1TloN GEollETRr VERS10~)
IJVARI`TE CORREL`TION
COEFFICI.flS 01 AClUAL
OPERAIOR I1E`SURE~NTS
~o -EWI' OR - rSrA£ES
Of 6EONETRIC SHHES
LKAT104 ~16
RfL`TIO~HIP DAT'
rES -KllROl
rLANE PARALLEL ?Ets?fcTlvE
-FRONT
-PL" ELEVAlIONS
-PL"
-SIDE
-CO~INAT10N
-CE*IER Of lNlEaEsT
-VIEdI~ ~INT
, _ _ _ _ . . . . . .
No -DEFI - LE IN TE - S -CONT`CT FOICES -uS`F FLrlK6 -JOINT CfNTERS DErEalNED Ir -lODr K'lcrED 1'
Of FOtCE lHrEucTTyE oll AND 6ETeEEII loor PERSONNEl -SE611ENT INERTI'l D'T' I`SE ELLIrSOIDS OR OTHfl
PLA~ES ~ ELLltsoTDs sf6nElTs -V'RIOUS "LE ~ fENALE PROPERIIES USER SPECIFIED SHA~E fO'
-~L ?lEssURf ON POPULATIONS -SfCHENT FORCE- SE6nfNTS AND DlsEL,rED
SURfm Of ELLIPSOIDS -3 A~D 6 rEil OILD DEfLECIION 111 3-DlNENslolts PIOJECTED
-RESTUAlilr SrSTEd CHILDREN C14ARAC1ERISTICS VIE' flON "r VlEllrOlIIT
TEL`CTloll -VARIWS TES1 DUmlES -Jolilr HorloN
-6uVI r~r lo"L f OtCES RESISTA~CE rRo'ERTlEs
-PIESCITIED fORCE o'
To~UE oll ANr SE6NENr
o -ANr SEATED UORTST`T10. NONE
DEf lNEr Ir THE USEI
-IST-99TH PERCENTILE lII -lODr SIIE
FORCE BALE ~ fEwE -IODY HotlLllr
plLors -CLOTH1N6 REsTllciloN -P`PER PLOTS
`RHr ~ N'V! IlAtE PILOTS -STREN6TH TO ANY SCAIE
-'IR FORCE HoNEN
IR1lr ilO~N
-OIHfLRS AS DEFINED Ir
USER
-VISION LlnlTs
-CREVSTl110NS
#.ONE -A#' MORISTITIO. DEflNETl-6RIVITY fOR IAL"CE -I.S.SO.9S ~ ~1H 2TILE -80DY SIZE
tr ~HE WEt c~uT'rloNs ~IR FORCE RALE ~ FE - E -8oDr ~lLlTr
~INlEN - CE TECHNICI"S, -CLOlHTN6 RESTIICT104 IE?RESElIll'N
-OTHERS ~S DEFIHED Ir USER-STIEK6TH "r SCALE 0N
-VISIO. Ll~lis cir
-CREITEI Ir roL26o,5
T~NSLllE' OS ROIlTEt
- PUcC5 C2ElTES HDLES
- NILL ~DD C 09 SUOT~Cr'6
-Ct~CTERS/LETTESS
-CONfO~:
CtElTES SURFICE tETNEEN
srHElEs
~C-CROUrS PSINITIYE
.
-NAS' ~STRONAUT FllES
rES -~`r IE VIEdED fROH
-100N ON c.R.r. ANr AN6LE: t ORT~
VIEIIIN6 PLAIIES
-~1r VIE' 2 SIItULT6IlEOUSlY
-~Ar BE lOTilE. ~
lCUTE ANCLES TO THE
VIEdINC ~ANE
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AlccuR`rE CAN IE VIEIIED fRON A#r
SCALE "LE
AXES:
.
fRONT ~ IAC!
TOP ~ 80~10K
(EFT ~ R16HT
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VER1 ICAL
l#/WT SCREEN
DINElRIC ~ ISONEIRLC
ORTH060N`l ~ PERSPECTIYE
OCR for page 67
67
C0KP'RISON RILE Of IkIEREiCE NODElS
I ABl ~ 0F C0RPAR' I I VE ~ l S
hODELS HIDK. LI~S OUTPUT
Rf NOVED
CO#TROLL1 D i EAIURi S ASS - 'T. IO#S -COHFUTEl-
17
.. . . . . . . . .
CAP -tES, 1K STOHE/ -~011[0# ~ CtEd -1EflO1ID
NCC4~EY VERSI~ ,CC~TED I! VISI~ -CAIDS
t~lD6. BLOC! AND K - , REA~ -DtSI
s rs I EN ~ E - l O~S - TAN
-THE SIONE/
bCCAUE, vIlst!
REOUIlES l~rEI-
ACTIVE CID/C"
TE~Illl~l
... . . .
S`I~IE TES
. . . .
· All tES
-IEACN
-aE,l - ES
-VlSlilLITr iSSESS~TS
COCI'lr lESI~S
. . . . . . . . .. . .. ..... . .. .
-SEC~11 t1NE68 ,~D -llICH 1~,UI
"CULAt lISPLICE~#IS,
YElOClilES A.
dCCfLER1TIOIIS,
Jolllr ollE*rArlo#s.
fOICES, - TO - UES
~ r,~cr rol~rs A
fOICES, ~ 01~1
f OICES
-1017 CEllEI ~ c~vlr~,
~.r~ Aue II.Erlc
ENE~!
-C",HIC~ DISnAt
SNWINC IODY POSITIO#
1N rlNE
.. . . . . .... ....
-~OUltES S~ClflC -llKl~lY IEOUIRES -ro~re'~ 77
4~THROPO~TRIC D'T' ESTIKATES Oi I - ~S,?-"INf~ 01 L6 - K181
FI. Il16 1ASE 01 SIA~O DEVIArlONS, S~ AS 11N, CDC, V,X,
ACTUAL D~tiTOlS "D CO'R~LATIOKS U#IV4C
. ... ... . .
-~1~ ~ SdEIIES
32 llr C - urE.
-~tI-S OPEIlil.C SYSrE,
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t-~' - ET
salrcHI.c rloroco~
tENOTE JOI EdTtY
EItILAT1011 '~S
-lEOUItES "1Nf - E
KIIIC~rE.
-CODE lH f - T" 77
-1~1 1~LENENIlTI~
lil~WE:
-Ffill~ELHEI
-tEc-
-IB!
~C
.. .. .. _ . . . . .
CO#Ill - ' -6UrOllAlED NI - EN -~ER PLOlS -Ll~l rE! (01 -Nl~ tESOLUT104 IODY -SElTEI -1~ ~1I~ - E {
lC01'Poter~z~ llNE IEKOVED -I~ER T"LES OR ALL tlOUSE O# SOKE SllE "D FROtO1110#, O,E1~101 EOUlY`LE#T)
ll~eet.eit..l 11 H" NODEL; d1CTIVITIES ,~O DATi IISPLiTS) SItENCIN, VIS10N, -YEClOI C~ICS
-~1) KANUALlY RElIOVEI -1~ flLES Of nOIS -AlPHAIHl~IERIC Rf~H -C~NICS ~JItOU1111 PAadC
~r WRItLACE Aal lAI' IETSOARD
-FUt.CT l O.i
IETIO4ID
CREli CHIEf -lUTOItlTED HIDDEN -SII'UL'TE ItilNTEN`NCE -6RIPHICS
LINt RfHOVil AS PROVIDED 11 CAD -DISRl~r-CRI
IN tUN-ltoKL; SOf IIIAREIH6RDVIRE -L 16HIPEN (OR
tlANUALLY REIIOVED NOUSE)
114 WRltPLACE, -tETIOiRD
OR OIHER lS -iLPHANURERIC
FROVIDED t' CAD fUNC110~1
SOf T`ARE
PLAID/ TENPUS YES
-CRF. REAC.'i
-IODY llAPPING
CONI OURS
-ANIBlTED MOTIONS
-CRElTES ldORIST`IION
.. . . .
VARIABLE 50DY SltE ~
PROPORTION, STREN6TH,
VISION, REACH,
lCCFSSltililY, INlfR-
ACT10N 11/ HAhD IOOLS
OtJECTS, 12 SIIRTIN6
POSTURES ADJUSTED
17 USER
. . . .. ... . . . .... . . .
-COlOR AV'IIAlLE
-DAll lDJUSTED fOR
IODY DlFfNSION
-CHAN6ES IN GRAVITY
-RETENTION t~ ItUlTIPLE
COPIES
-DISPL'YS REICH DAT'
ldlil 9E iVIILA4lE -fOLlO.S CAD SOfT\litE 01
IN 1988 srsTERs CiD" (It~l)
. .
-V`X 111785
-INPUTS rEITRONIX TERtII"LS
Representative terms from entire chapter:
crew chief
