Technical systems must be supervised or operated by humans in all aspects of human-

machine-environment systems, e.g., in the household, automobiles, consumer

electronics, or in traffic. These examples show – and everyone has probably had

experience with these – that the design of systems provided to humans is not always

optimal, i.e., user-friendly. In order to offer hazard-free handling and error-free human-

machine interaction, it is vital that the characteristics and capabilities of future users are

taken into account. In addition, the ergonomic design of products has substantial meaning

for the acceptance of appliances. A mobile phone, for example, that is more complicated

to operate than competitors‟ products (because fundamental ergonomic principles were

not incorporated) is no longer capable of competing in today‟s market. Early inclusion of

ergonomic aspects during product development thus also leads to a better market

position and a reduction in costs due to later product changes.

Design of products, however, continue to be often left up to designers and drafts men

who do not have specific knowledge on ergonomics. This can clearly be seen in the

design of current consumer electronics products, computer software and mobile

telecommunications: the user is completely overwhelmed by the excess of functionality

and highly complex system structures (e.g., nested menus, hidden functions).

What is Product Ergonomics?

What is Usability Engineering?

Product ergonomics involves adapting products to their users‟ characteristics so that the

products can be used more easily.

Anthropometry in product ergonomics primarily involves consideration of measures and

measurement ratios in the design of future product and work places. Based on body

dimensions, cars, for example, have their seating geometry, layout of operating elements

(steering wheel, gear shift, pedals), operating force as well as the visibility of their

instruments laid out.

The principles introduced in the information technology design can usually also be

transferred to the design of software.

The layout of the car console (here: Daimler‟s Innovative Concept Study) places high demands

on anthropometric design. Included is the visibility/outside view and readability of indicators

and instruments, obscurities (e.g. due to steering wheel or operating elements) as well as the

range (reachability and operation of operating elements) or the actuating force (operation of

pedals, switches and steering elements). Furthermore, dis(comfort) due to confining posture

must especially be considered, particularly for driving long distances.

The most prominent innovations illustrated in the image above is an imaginative new driving

control system which allowed the driver to control all vehicle movements by means of side-

sticks positioned in the door trim panels and in the centre console of the coupé study. Moving

the side-sticks to the left or right steered the vehicle, pushing the levers forwards accelerated it,

pulling it backwards, applied the brakes. The interior of the F 200 Imagination was completely

devoid of conventional control and connecting components, such as a steering wheel, steering

column or pedals – each and every command from the driver was transmitted electronically, a

system which the experts referred to as "drive-by-wire". The F 200 Imagination study also

presented the Mercedes design team with an ideal opportunity to show how the omission of

the steering wheel and pedals opened up whole new possibilities for the interior styling and

controls of the passenger cars that we would be driving in years to come. The driving control

system in the F 200 Imagination was coupled to an active suspension system which adapted

the vehicle's suspension and damping characteristics to the current handling conditions. The

result was, improved driving safety and ride comfort, something which made the F 200 a

mobile laboratory for the Active Body Control system which premiered in Mercedes-Benz

series-production models in 1999.

The eye-catching steel panels bordering the glass roof of the F 200 Imagination also housed

electronic cameras which removed the need for interior and exterior mirrors. Instead, monitors

fitted inside the study's cockpit kept the driver fully informed of what was going on behind the

car.

Source: http://www.daimler.com

The second example is of an airplane cockpit for the study of a passenger plane with two

motors based on the AIRBUS cockpit concept. Through the airplane‟s outer structure the

outside view and the position of the pilot is given in the cockpit. Aside from the numerous

SAE, JAR and FAA standards, particularly long operational durations and the wide

spectrum of global users are typical for cockpits.

From an anthropometric perspective, taking visibility into consideration, i.e. outside view

at start and landing and during taxiing on the runway, and visibility of instruments, is just

as important as the reachability of operating instruments through various safety belt

functions using a 5-point belt. With the Fly-by-Wire artificial steering forces contribute to

easier steering. Paying attention to posture comfort is especially important for long flights

(transatlantic).

A similar concept is found in several AIRBUS airplanes and makes the re-training of pilots

from one type to another more simple. This is necessary in almost all airlines during the

course of a career/promotion. Actually, the user interface of an A319/320/321 can be

distinguished from that of a A330/A340/A380 only by design. But regardless of the same

user interface elements, it is important to say that flight characteristics and flight dynamics

can be significantly different.

In practice, mostly a mixture in design exists:

Purely prospective/planning ergonomics is impossible e.g. in automobile creation since

standards and pre-designs must be taken into consideration as a basis. A benefit of a

pre-design is, through the identification with the brand, an easy transition from one type to

the next: this minimises the training time and increases the reliability.

A continuous modification of existing driver workplaces results, which leads to a mixture

of various ergonomic approaches.

The later the changes and counterbalancing measures are recognised and put into

action, the higher are the resulting costs and necessary recalls. A strict adherence to

deadlines with simultaneous high quality is becoming increasingly more difficult,

especially in relation to the increasing relevance of the “just in time” delivery and the

consequences of delays.

There is a close relationship between general ergonomic design criteria and

anthropometric design.

Therefore, the maximum forces acting on humans are to be taken into account in terms of

harmlessness. Obviously, a failure to notice can easily lead to health damages (e.g.

slipped discs during lifting). The feasibility must be ensured through a meaningful layout

of operating elements (reach ability, operation) and instruments (visibility). A product such

as an automobile cannot be steered if important elements like the steering wheel or the

pedals are not reachable for majority of the users. In regard to higher criteria such as

tolerability and avoidance of interference, damaging body postures and overstraining are

to be avoided; it is also important to ensure a high level of comfort through the design.

Personality development answers general questions regarding the “well-being”. However,

aspects of colour design for the instruments as well as design aspects are more related to

aesthetic levels.

Three requirements of ergonomic design of products can be derived from slide 10-10.

The historic foundations of anthropometry are, aside from the representation of humans in

art, especially found in architecture. As humans were often seen as an image of God,

“godly” and perfect proportions were thought to be made possible by incorporating human

proportions into the building design. Thus, many medieval structures, particularly sacral

buildings, are based on human proportions.

Body measurements were also used in daily life as a form of measurement. The reason

for this is the lack of a universal relative measurement system, such as the “Urmeter”.

Instead, available body measurements would be used: the inch is the length of the first

thumb joint, a cubit the length from the elbow to the tip of the finger, and paths could be

measured with the even “Feldrute” in which 16 people would line up in a row, one behind

the other.

With the Renaissance anthropometry was used in medicine, especially in anatomy, in

order to scientifically identify the skeletal structure and the inner composition of the

human body.

Da Vinci in particular occupied himself with solid results about the build of the human

body. His goal was a representation in beautiful artwork, but also the practical use of the

acquired anthropometric insights in the design of tools. As appliances or tools were until

now only developed through “evolution”, i.e. good designs were pursued, bad ones were

discarded, a goal oriented, almost scientifically engineered design was now possible.

There are numerous anthropometric measures. These days the principle that counts is:

what can be measured will be measured. In sight of product ergonomics, there is still a

large portion of the total measure that is interesting. These are listed here. An overview of

large data collections can be found in the standards. Besides body sizes, general

conditions for data collection can be found here. These must be adhered to in

implementation since errors may otherwise occur. For example, most body sizes are

collected from unclothed persons in standard positions (perpendicular seating): however

this case can rarely be found in practical usage. Therefore, safety margins are necessary

during product design. Additionally, differentiation/characterisation of measured samples

must be taken into account since there are great differences in body sizes as well as body

proportions between the sexes, age groups and regional groups. Different body sizes are

often combined for general characterisation of physique and corpulence. Thus, heavy-set

short people can openly be distinguished from lean people, which can then also be taken

into consideration during product design.

The limitation of using only one value for the description of body size (e.g. the average) is

not reasonable since more than one user will be using a product later on. Instead,

percentages are used in anthropometry which cover a range. A percentage indicates how

much of the population fall below the measurement. The 5th percentile thereby refers to a

short person since only 5% of the entire population is shorter. The 95th percentile is a tall

person, since 95% of the population is shorter and only 5% is taller. Length

measurements such as body height are normally distributed so that a simple relation

between percentile and mean/standard deviation exists. The mean relates to the 50th

percentile (50% are shorter than that measurement) and the 5th, i.e. 95% less than the

mean, or in addition 1.96 times the standard deviation. In practice, the 5th and 95th

percentile are used.

As can be seen from the diagram, there are further differences between the user groups

that must also be considered: differences in sex are especially important here. Thus, a

body height of an average female (50th percentile) corresponds to a rather short male

(5th percentile). Similarly, sex-specific differences also exist for other body sizes and

proportions. A mixing of data for females and males would not make sense since the

differences would no longer be sufficiently taken into consideration. Instead, different

analyses for product ergonomics are necessary.

For safety-relevant measurements the 1. or 99. percentile is usually used.

The values given in the table are based on statistically validated measurements of

persons from the Federal Republic Germany (DIN 33402).

In the industry, work materials and workplaces, whose measurements are to correspond

to the body dimensions of the person, cannot always be designed for each individual

user due to economic reasons. Therefore, it is necessary to establish a basis for the

adaptation of work materials and the workplace to the body form of as many users as

possible by using statistical data. Thereby, depending on task and usage type, it is

possible to attain different workplace sizes, adjustments or a design applicable to all

users.

Aside from differentiation between the sexes, differences between age groups, regions

and clothing must also be included. This is especially true for when products are

designed for global markets.

Region/Cultural dependencies of measurements: A 95. percentile Vietnamese, and thus a

notably tall man from this region, is approximately equal to a 10. percentile central

European. The range from the .5 to the .95 percentile man from the “South East Asian”

region amounts to 153-172 cm.

Also see: Sanders & McCormick, 1993, pp. 420ff

Height and corpulence

Body sizes are not independent of one another, rather, they strongly correlate with each

other. Body sizes within a group (e.g. high and long measurements as well as reaches)

possess a high correlation with one another, while the correlation between body sizes of

different groups is practically non-existent: not every large person is overweight!

The statistical tool of factor analysis can be used based on the correlations in order to

combine similar sizes. In anthropometry something similar occurs through the use of

index values.

There are three types of body sizes: the body height, the corpulence and the proportion

(sitting giant/sitting dwarf).

An optimal product design takes into consideration not only small or large people (height),

but also the corpulence and proportions. Instead of two values (big, small) there are

actually 8:

Big, slender, short-legged

Big, corpulent, short-legged

Big, slender, long-legged

Big corpulent, long-legged

And the same for small persons.

Differences between sex and age group must also be considered.

Through the course of time a general increase in body size, especially in industrial

nations, can be noted. This occurrence called the increase of body dimensions takes

place primarily due to improvements in living conditions (hygiene, nutrition, work

conditions).

An extrapolation for the adaptation of older tables or to the estimation of future ones

remains problematic since the increase in sizes do not occur continuously, and no reliable

prediction about a possible end of the increases is available.

However, as an example, increase of body dimensions was calculated up until the year

2050 for the Airbus A380 so that passengers will still have comfortable seating (Bauch,

2001, www.haw-hamburg.de/pers/Scholz/dglr/bericht0101/Bauch.pdf)

Human action forces play a role for all mechanical performances. They occur during the

maintenance of body positions, during the execution of free or steered body movements

or its extremities, during the use of work tools, in the operation of operating elements, or

during the manipulation of loads. Physical strengths are developed as muscular strengths

within the body, work as mass force (force of inertia) from the outside onto the body or are

transferred by the body as action forces to the outside.

Physical forces can be used for the design of work media for various goals. For example,

data collection, from the viewpoint of comfortable usage could be for, the way to design

the operating elements‟ operational resistances that should be served in an automobile.

For the continuous manual regulation of dynamic processes, however, the question still

remains regarding which level of operating resistance operating elements must have, in

order to deliver an adequate proprioceptive (realisation of stimuli arising from own

organism) response about the movement procedure.

Dynamic (Functional) Dimension: Active area of the hand-arm-system

Aside from measures for the performance of functions (work areas, areas of joint

movement), safety measures (safety, minimum and maximum distances) and space

requirement measures (space requirements, compensational movement) can also be

differentiated.

Aside from static anthropometry it is getting more and more important to account for

dynamics since in reality, postures are never static but always fluctuate around average.

Especially work is always bound to deliberate movements. For movement planning, a

comprehensive methodology to capture and document data like in anthropometry is not

yet available. There is even a stronger diversification and variability of movements. Even

the same person never moves exactly the same way twice. So besides the inter-

individual diversification, there is also an intra-individual diversification. Hence, for

movement planning, the ergonomic planner has to rely on estimations of spacial

requirements or single movement tracks.

A specific movement is partitioned into several phases. The actual movement first has a

design phase in which a pre-programmed movement takes place. The movement itself

divides into two other phases: the ballistic and the visually controlled phases. The first

phase serves for quick guidance towards the goal, while a fine-tuning occurs in the

second phase.

The temporal division of these two phases amounts approximately between 2/3 to 1/3.

Approaches of varying complexity are available for the characterisation of movement:

Temporal and spatial characteristic data are easy to use, yet simplifies a movement too

much and therefore only are suitable for narrowly outlined special areas (e.g. methods-

time-measurement or work-factor-processes in the scope of production planning).

Motion paths, or trajectories, express spatial relationships. The problem is the

summarization and meaningful preparation and presentation of the multitude of possible

motion paths.

Bio kinematic models are based on different approaches (e.g. biomechanics or inverse

kinematics) and allow an exact replication of individual movements for digital human

models or in simulations. However, the variability of the movements is also a problem

here. Still, due to their high level of clarity and face validity of presentations, they have

managed to have been supported by all human models.

Fields of vision (upper left: different areas of the field of view – pay attention to colour

dependencies!) and thereby the recognisability and readability of instruments (dependent

on vision – Visus 1 (normal): 1 arc minute resolution) are equally as important as

anthropometry.

The design of vehicles begins with a fictitious eye-point (Design-Eye-Point, airplane) or

from an eye ellipse (auto) in which the eye of the future user exists.

Airplane (bottom left):

Design Eye Position (eye-point):

... Is a set point relative to the airplane structure upon which the eyes of the pilot are to

be in the normal seating position (SAE ARP 4202); fixing of the pilot‟s position in the

cockpit; seating adjustment area is to be fixed so that all pilots can attain positions in

the DEP

Line of Sight

The line of sight provides the line of vision during landing; sloped downward (angle of

incidence during landing)

In practice, the verification of the sight requirements can also be done through lines of

sight in CAD or in technical drawings. It is easier to do so with human models (bottom

right) which present the fields of view as cones, or that directly calculate the view of the

user.

Somatography (Greek): sketching of bodies

In video somatography the video image of a test person is superimposed full-scale on a

drawing or a model of the workplace.

The test person can coordinate his/her movements through a control monitor (Luczak, 1998,

p. 599f; Original in Martin, 1981)

Body templates exist for various body heights in front and side views as well as top view. The

indication of joint centre points allow an easy presentation of different body positions for the

verification of the design measurements of workplaces.

body templates: DIN 33408 Teil 1, also see: Pahl et al., 1996, p. 306; Pahl & Beitz, 1997, p.

368; Luzak & Volpert, 1997, p. 382

somatography: Sanders & McCormick, 1993, pp. 419-420

physical models: Sanders & McCormick, 1993, pp. 422-423

(bottom left): Bosch Template – 4 simple templates for: 5. Perc. Female, 50. Perc. Female/5.

Perc. Male, 95. Perc, Female/50. Perc. Male, 95. Perc. Male. The rules of technical drawings

are in effect, therefore three-dimensional results in technical drawings are also possible.

Significant simplification of the joints (point joints), but with indication of maximum angles.

(bottom right): Kiel Doll – 6 complex templates for 5., 50., 95. Perc. Female and Male. KD

available in side view for different measurements (standardised according to DIN 33408) .

Top view also available, though in practice barely used due to low practicality. Typical are link

joints for the shoulder, hip, and knee that make exact reaching range possible. There is

limited area of application since results only count for shoulder height, i.e. not movements to

the side (which is common in reality).

Today, digital human models have prevailed due to the spread of CAD. If full-scaled CAD

outputs are produced in the beginning stages into which templates are entered, then in

the digital human models body dimensions are directly taken into account in CAD.

The human models contain databases with anthropometric measurements (body

dimensions, field of vision, joint angles, forces), a movement simulation and additional

analysis tools which not only make the analysis of reachability and vision, but also the

considerations of comfort, possible.

Depending on the model, two basic procedures can be derived:

1 – Model in CAD:

Here, the digital human model is integrated into the CAD environment (e.g. Anthropos in

CATIA). The geometry of the product does not first have to be exported and transformed,

rather, it is already complete and in the correct layer format. Changes can be made

directly in the primary version of the design. The advantage is that no losses occur during

the transfer of the design into other CAD environments, and changes can be integrated. A

disadvantage is that a slower calculation of the CAD model occurs which was only

implemented here as a model of the CAD environment.

2 – Design analysis in the human model environment

The design is exported (partially) from the original CAD environment and then imported

into its own human model environment (with significantly less options than in CAD). The

analyses are then conducted here. The advantage is a faster calculation (since the entire

CAD environment is already running in the background). A disadvantage, however, is the

problems in the transfer of the design from CAD into the human model.

Here is an example for the general procedure of anthropometric product design

Generation of the first human model:

Basic options (left):

(1) Generation of the first representative human model via a database query (common in

human model). An important consideration during this procedure is the relationship to the

user group, i.e. differentiation according to sex, nation, age, increase of body

dimensions, increase in height, corpulence and proportion

OR

(2) Generation of own human model based on anthropometric dimensions. The model is

hereby extrapolated and calculated through the input of a variety of different reference

dimensions.

The model along with the (simplified) product design are then presented in an

environment.

In the second step the task and the restrictions are defined:

1. The posture is determined according to the inputs of the seating reference point/hip

point and the incline of the seat/backrests.

In addition, contact surfaces and the positions of the operating elements are

determined and then entered into the human model.

2. Next, the body parts and the posture (e.g. contact or gripping grasp) are determined.

3. Finally, the animation (calculation of the posture) takes place via the human model

along with the first visual plausibility test.

“Simple” analyses such as fields of vision and spaces within reach/reachable areas are

then carried out by the model. Fields of vision are shown as cones for “outsiders” as well

as for the particular model.

Through a change in the model a plastic impression of the future view is attained.

Spaces within reach can be directly presented for the planning ergonomics, and can thus

be take into consideration by operating elements.

For ergonomics of testing the reachability of operating elements can be directly tested by

entering tasks (see previous slide). In this case the proper posture is also accounted for.

Important: CAD environments allow for a preferred level of accuracy in such examinations

(1/10. mm are not a problem). However, the anthropometric data as well as the posture

data are not as accurate. In practice, especially for spaces within reach or collisions with

the product, safety margins of at least 1 cm should be used.

The analysis of posture comfort is more complex. Height as well as body dimensions

(these are of a general nature and independent from the product), joint angles (these are

depending on the product) and forces on the joints (details) are included in this analysis.

By regression respectively comfort models it is possible to get a value of (dis-)comfort out

of the input values.

IMPORTANT: Do not simply follow these instructions without being critical. Instead, check

for which boundary conditions discomfort calculations were validated. Thus, vehicle

considerations (e.g. automobile manufacturing) cannot be taken over by all areas (e.g.

maintenance) without problems - particularly problematic are the differences in posture

(sitting/standing). A transfer here is impossible.

An uncritical reliance on data leads to errors!

With an individual model no user-collective can be reproduced. Hence, the analyses are

to be repeated with additional models. Depending on the complexity of the collective this

may encompass more than 10 models. This is the only way that problem areas (see

slide‟s head collision of large man of medium corpulence and medium proportion) can be

identified and corrected.

These pictures show that the simulated movements and postures of mannequins cannot

simply be used without limitation for the design of products. Several misinterpretations

can be seen that are shown through the movement apparatus and the theoretically

allowable degrees of freedom, and which are theoretically acceptable according to the

mathematical relationships of the human model, but which cannot actually be captured by

a human.

This is especially true for the body angles or torsions and the penetration of adjacent

objects.

RAMSIS is the 3D CAD ergonomics tool. Package and design studies during the design

phase of a vehicle can be extensively processed with RAMSIS. RAMSIS is the global

leader of CAD tools for ergonomic design and analysis of vehicle interiors and workplaces

and is used by more than 60% of all automobile producers.

Advantage: Extensive analysis is already possible in the pre-production phase without

requiring building of expensive physical models. (also see Luczak & Volpert, 1997, p.

383f)

Anthropometric Database 90 real, statistically validated body types

Standard animation: Translation/rotation interactively or numerically, joint animation

numerically or interactively, fast automatic target point animation for freely definable

chains of body parts, interactive drawing of body part chains, analysis of spatial

coordinates and joint angles

Restrictive animation: Marginal posture calculations, body type independent task

description, interactive goal definition, consideration of interfaces, tangential ability

requirements, consideration of self-intersection

Health and comfort analysis: Analysis of posture comfort, posture-dependent body part

comfort evaluation, fatigue analysis, orthopaedic evaluation of spinal curvature

Vision analysis: Incorporation of eye, head and neck movements into restrictive

animation, internal sight, ergonomic evaluation of the field of vision, consideration of focal

distance, simulation of mirror view

Belt analysis: Calculation of belt routing, calculation of seatbelt points

Reach ability Analysis: Body type-dependent calculations of reach ability levels, (also) for

extremities, calculation of reach ability surfaces for body part chains.

The human body model JACK„s main background is in computer graphics , for example in

animation of virtual humans in movies. In anglophone countries, it is also used for product

design (primarily automotive) and as tool for educational training movies.

Main objective of JACK today is beside of product design also the display of humans in

virtual environments. With special hardware, JACK is kind of remotely controlled and

follows the real human„s movements. When aditionally displaying the virtual sight of

JACK, the user gets the impression of personally sitting in the vehicle. This makes quite

early and detailled product analysis possible.

The database of body measurements is primarily based on US-American data sets. They

are represented as percentiles. JACK offers functionality for analysis of sight, range,

postures and movements.

Delmia (Digital Enterprise Lean Manufacturing Interactive Application) by Dassault

Systems is a software for planning, visualisation, simulation and validation for production

planning. Delmia is making first attempts to pursue the idea of digital manufacturing and

includes an integrated human model, DELMIA human.

Focus of development has been to model body measure variability for vehicle interior

design. Similar to RAMSIS, there an exhaustive methodology which by far exceeds

simple percentile measures.

Existing analysis capabilities comprise vision, reach, postures and movement analysis.

Additionally, there are functionalities to execute methods-time-measurement, force and

performance analysis.