Industrial engineering ae 481

INDUSTRIAL ENGINEERING
Course Code: AE 481
Course Teacher-
Salima Sultana Shimo (SSS)
Assistant Professor
Dept. of Industrial & Production Engineering
Bangladesh University of Textiles

ERGONOMICS
 the study of the interaction between people and machines and the factors
that affect the interaction
 The term "ergonomics" is derived from two Greek words: "ergon,"
meaning work, and "nomoi," meaning natural laws
 Ergonomists study human capabilities in relationship to work demands
 ergonomics is a systems-oriented discipline which now extends across all
aspects of human activity
 promotes a holistic approach in which considerations of physical,
cognitive, social, organizational, environmental and other relevant factors
are taken into account
 Practitioners of ergonomics and ergonomists contribute to the design and
evaluation of tasks, jobs, products, environments and systems in order to
make them compatible with the needs, abilities and limitations of people

ERGONOMICS (cont…..)
Ergonomics helps harmonize things that interact with people in terms of people’s
needs, abilities and limitations.

PURPOSE
 to improve the performance of systems by improving human machine
interaction.
 This can be done by ‘designing-in’ a better interface or by ‘designing-out’
factors in the work environment, in the task or in the organisation of work that
degrade human–machine performance.
 Systems can be improved by
• Designing the user-interface to make it more compatible with the task and
the user. This makes it easier to use and more resistant to errors that people are
known to make.
• Changing the work environment to make it safer and more appropriate for
the task.
• Changing the task to make it more compatible with user characteristics.
• Changing the way work is organised to accommodate people’s
psychological, and social needs.

 The implementation of ergonomics in system design should make the
system work better by eliminating aspects of system functioning that are
undesirable, uncontrolled or unaccounted for, such as
• Inefficiency – when worker effort produces sub-optimal output.
• Fatigue – in badly designed jobs people tire unnecessarily.
• Accidents, injuries and errors – due to badly designed interfaces
and/or excess stress either mental or physical.
• User difficulties – due to inappropriate combinations of subtasks
making the dialogue/interaction cumbersome and unnatural.
• Low morale and apathy.
 In ergonomics, absenteeism, injury, poor quality and unacceptably high
levels of human error are seen as system problems rather than ‘people’
problems, and their solution is seen to lie in designing a better system of
work rather than in better ‘man management’ or incentives, by ‘motivating’
workers or by introducing safety slogans and other propaganda.

History of the field
 In ancient societies
Greek civilization in the 5th century BC used ergonomic
principles in the design of their tools, jobs, and workplaces. One outstanding
example of this can be found in the description Hippocrates gave of how a
surgeon's workplace should be designed and how the tools he uses should be
arranged.

 In industrial societies
In the 19th century, Frederick Winslow Taylor pioneered the
"scientific management" method, which proposed a way to find the
optimum method of carrying out a given task. Taylor found that he
could, for example, triple the amount of coal that workers were
shoveling by incrementally reducing the size and weight of coal shovels
until the fastest shoveling rate was reached. Frank and Lillian Gilbreth
expanded Taylor's methods in the early 1900s to develop the "time and
motion study".
 Information age
The dawn of the Information Age has resulted in the related field of
human–computer interaction (HCI). Likewise, the growing demand for
and competition among consumer goods and electronics has resulted in
more companies and industries including human factors in their product
design.

 Domains of specialization
Domains of specialization within the
discipline of ergonomics are broadly the
following-
 Physical Ergonomics
o Physical ergonomics is concerned with
human anatomical, anthropometric,
physiological and biomechanical
characteristics as they relate to physical
activity.
o Relevant topics include working postures,
materials handling, repetitive movements,
work related musculoskeletal disorders,
workplace layout, safety and health.

 Cognitive Ergonomics
o Cognitive ergonomics is concerned with
mental processes, such as perception,
memory, reasoning, and motor response, as
they affect interactions among humans and
other elements of a system.
o Relevant topics include mental workload,
decision-making, skilled performance,
human-computer interaction, human
reliability, work stress and training as these
may relate to human-system design.

 Organizational Ergonomics
o Organizational ergonomics is concerned with
the optimization of socio-technical systems,
including their organizational structures,
policies, and processes.
o Relevant topics include communication, crew
resource management, work design, work
systems, design of working times, teamwork,
participatory design, community ergonomics,
cooperative work, new work programs, virtual
organizations, telework, and quality
management.

 Value of Ergonomics Today
o Many people suffer because their conditions at work and home are
incompatible with their needs, abilities and limitations. This
situation affects their safety and welfare, as well as, that of
organizations and societies.
High technology can make our lives more efficient and exciting.
However, fascination with technology and overly ambitious business
expectations can cause us to overlook human factors risks.
Neglecting these risks can have serious effects on manufacturers,
suppliers and service enterprises.

Human Machine Interface Systems
 Human Machine Interface (HMI) Systems provide the controls by
which a user operates a machine, system, or instrument.
 Sophisticated HMI Systems enable reliable operations of technology
in every application, including high-speed trains, semiconductor
production equipment, and medical diagnostic and laboratory
equipment.
 HMI Systems encompass all the elements a person will touch, see,
hear, or use to perform control functions and receive feedback on
those actions.

Human Machine Interface Systems(Cont….)
 The task of an HMI System is to make the function of a technology self-
evident to the user. The effectiveness of the HMI can affect the acceptance
of the entire system; in fact in many applications it can impact the overall
success or failure of a product.
 The HMI System is judged by its usability, which includes how easy it is to
learn as well as how productive the user can be.
 It is the mission of everyone involved in the HMI design, the engineers,
management, HMI consultant, and industrial designer, to meet the defined
usability requirements for a specific HMI System.

Human Machine Interface Systems(Cont….)
These are outputs from the machine or computer that stimulate the human sense
of hearing or touch, respectively. Human motor responses come by way of our
fingers, hands, arms, legs, feet, and so on, and are used to control the machine or
computer. Of course, speech or articulated sounds are also human responses and
may act as controls to issue commands to the computer or machine.
Figure 1. Classical view of the human-machine interface

How to Design an HMI System
 A highly-reliable HMI System that delivers safe, cost-effective,
consistent and intuitive performance relies on the application of
engineering best practices throughout design and panel layout,
production, testing, and quality assurance processes.
 Just as critical, in-depth knowledge of and compliance with all
relevant ergonomic, safety, and industry standards must inform each
step of the design and manufacturing cycle. Steps are as follows:
1. Defining Operational/Functional Requirements
2. Define the Operator
3. Choosing the Best Control Technologies
4. Connecting/Communicating with an HMI System
5. Safety Considerations

1. Defining Operational/Functional Requirements:
The tools needed for effective operator control of the equipment as well as the
requirements of the overall application determine the selection of interface
functions.
Degree of Input Complexity:
Input can be as simple as an on/off switch or a touch screen
display. Touch screen HMI Systems are increasingly popular in public
transaction applications, because they can simplify complex operations and
tolerate a moderate degree of rough use.
Operator Feedback:
Feedback can be visual, auditory, tactile, or any combination
necessary for the application. Feedback is essential in systems that have no
mechanical travel, such as a touch screen or a capacitive device that when
triggered has no moving parts. In some cases feedback provides confirmation of
an action, while in others it adds to the functionality.

1. Defining Operational/Functional Requirements (Cont….)
Lifecycle Durability:
Not only should the HMI System be rugged enough to
withstand the elements and heavy use, but it should also last for the
duration of the equipment lifecycle. For example, a Magnetic Resonance
Imaging (MRI) HMI System interface should last at least 10 years.
Style:
HMI style considerations are effective when they create a level of
product differentiation that delivers a unique selling proposition.

2. Define the Operator:
The key to a successful HMI System implementation requires a well-grounded definition and
understanding of the operators. For any user along the range from intuitive to expert,
interface ergonomic considerations should include: panel layout, HMI Component
selection, information presentation, feedback, and safety considerations.
Panel Layout: The panel layout should be designed to provide the operator functional
groups of related information in a predictable and consistent manner. In addition, the
system must require an operator to initiate action and keep the operator informed by
providing timely feedback on those actions. The layout should be organized so that the
operator is clearly prompted in advance when the next operator action is required.
HMI Component selection : HMI designers can simplify their search for the appropriate
switch or HMI Component by carefully analyzing their application requirements then
determining the following:
Electrical ratings.
Actuation preferences (momentary, maintained, rotary, etc.).
Physical configuration and mounting needs.
Special requirements such as illumination, marking, environmental sealing, etc.

Define the Operator (Cont…...)
Color scheme : The key to effective use of color is simplicity. Avoid too
many colors or flashing alarms. Stick with the “traffic light” model for key
actions:
Red for stop/failure/fault.
Yellow for warning.
Green for OK/start/go/pass.
Information presentation : Once again, simplicity is the key. Don’t crowd a
screen – avoid cluttering it with irrelevant data. Forcing an operator to
search for the required information increases response time and potential
errors. Have a consistent set of menu buttons and functions from screen to
screen.
User Feedback : Feedback is critical to ergonomic industrial design. Make
sure the results of pressing a control button, toggling a switch, or entering a
command are absolutely clear. Determine if operator feedback is visual,
auditory, tactile, or a combination of multiple techniques.

3. Choosing the Best Control Technologies:
Once you have defined HMI functionality, you are ready to investigate
control technologies. Each technology has advantages and disadvantages
related to the HMI system, equipment, and application.
 Cursor Control (Trackball, keypad, touchpad, etc.)
 Switches (Pushbutton, rocker, slide, key lock, rotary, etc.)
 Short travel technologies (keyboard, keypad, etc.)
 Touch and switching technologies (Capacitive, high frequency, etc.)
 Interactive Displays, Touch screen
 Motion Control

4. Connecting/Communicating with an HMI System:
 Once you have established how your HMI will look, feel, and operate, you
need to consider how the HMI will connect to and communicate with the
core equipment or system under control. Typically, communication can be
achieved through several approaches: hard wired connection, serial bus
connection, or wireless connection.
5. Safety Considerations:
 For HMI Systems design, safety considerations are a critical part of the
system. Human error is a contributing factor in most accidents in high-risk
environments. Clear presentation of alarms as well as the ability to report
errors, are crucial elements in any HMI.
In addition, emergency stop switches, generally referred to as E-Stops,
ensure the safety of persons and machinery and provide consistent,
predictable, failsafe control response. A wide range of electrical machinery
must have these specialized switch controls for emergency shutdown to
meet workplace safety and established international and domestic
regulatory requirements.

Principles of Ergonomics
 Principle 1:Work in Neutral Postures
Maintain the "S-curve" of the spine
Keep the neck aligned
Keeps elbows at sides
Keep Wrists in Neutral
 Principle 2:Reduce Excessive Force
 Principle 3:Keep Everything in Easy Reach
 Principle 4:Work at Proper Heights
Do most work at elbow height
 Principle 5:Reduce Excessive Motions

 Principle 6:Minimize Fatigue and Static Load
 Principle 7:Minimize Pressure Points
 Principle 8:Provide Clearance
 Principle 9:Move, Exercise, and Stretch
 Principle 10:Maintain a Comfortable Environment
Lighting and Glare
Vibration
Note: The above principles all address physical issues, those items that
people are most interested in currently. Two additional "principles"
are:
 Make displays and controls understandable
 Improve work organization

Evaluation Methods for Human Factors and
Ergonomics
Until recently, methods used to evaluate human factors and ergonomics ranged
from simple questionnaires to more complex and expensive usability labs.
Some of the more common HF&E methods are listed below:
 Ethnographic analysis: Using methods derived from ethnography, this
process focuses on observing the uses of technology in a practical
environment. It is a qualitative and observational method that focuses on
"real-world" experience and pressures, and the usage of technology or
environments in the workplace. The process is best used early in the design
process.
 Iterative design: Also known as prototyping, the iterative design process
seeks to involve users at several stages of design, in order to correct
problems as they emerge. As prototypes emerge from the design process,
these are subjected to other forms of analysis as outlined in this article, and
the results are then taken and incorporated into the new design. Trends
amongst users are analyzed, and products redesigned. This can become a
costly process, and needs to be done as soon as possible in the design
process before designs become too concrete.

 Meta-analysis: A supplementary technique used to examine a wide
body of already existing data or literature in order to derive trends or
form hypotheses in order to aid design decisions. As part of a literature
survey, a meta-analysis can be performed in order to discern a collective
trend from individual variables.
 Subjects-in-tandem: Two subjects are asked to work concurrently on a
series of tasks while vocalizing their analytical observations. The
technique is also known as "Co-Discovery" as participants tend to feed
off of each other's comments to generate a richer set of observations
than is often possible with the participants separately. This is observed
by the researcher, and can be used to discover usability difficulties. This
process is usually recorded.
 Surveys and Questionnaires: A commonly used technique outside of
Human Factors as well, surveys and questionnaires have an advantage
in that they can be administered to a large group of people for relatively
low cost, enabling the researcher to gain a large amount of data. The
validity of the data obtained is, however, always in question, as the
questions must be written and interpreted correctly, and are, by
definition, subjective. Those who actually respond are in effect self-
selecting as well, widening the gap between the sample and the
population further.

 Task analysis: A process with roots in activity theory, task
analysis is a way of systematically describing human interaction
with a system or process to understand how to match the
demands of the system or process to human capabilities. The
complexity of this process is generally proportional to the
complexity of the task being analyzed, and so can vary in cost
and time involvement. It is a qualitative and observational
process. Best used early in the design process.
 "Wizard of Oz": This is a comparatively uncommon technique
but has seen some use in mobile devices. Based upon the Wizard
of Oz experiment, this technique involves an operator who
remotely controls the operation of a device in order to imitate the
response of an actual computer program. It has the advantage of
producing a highly changeable set of reactions, but can be quite
costly and difficult to undertake.
 Top Modeler: This model helps manufacturing companies
identify the organizational changes needed when new
technologies are being considered for their process.

 Think aloud protocol: Also known as "concurrent verbal protocol",
this is the process of asking a user to execute a series of tasks or use
technology, while continuously verbalizing their thoughts so that a
researcher can gain insights as to the users' analytical process. Can be
useful for finding design flaws that do not affect task performance, but
may have a negative cognitive affect on the user.
 User analysis: Best done at the outset of the design process, a user
analysis will attempt to predict the most common users, and the
characteristics that they would be assumed to have in common. This can
be problematic if the design concept does not match the actual user, or if
the identified are too vague to make clear design decisions from. This
process is, however, usually quite inexpensive, and commonly used.
 Methods Analysis is the process of studying the tasks a worker
completes using a step-by-step investigation. Each task in broken down
into smaller steps until each motion the worker performs is described.
Doing so enables you to see exactly where repetitive or straining tasks
occur.

 Time studies determine the time required for a worker to complete each
task. Time studies are often used to analyze cyclical jobs. They are
considered "event based" studies because time measurements are
triggered by the occurrence of predetermined events.
 Work sampling is a method in which the job is sampled at random
intervals to determine the proportion of total time spent on a particular
task. It provides insight into how often workers are performing tasks
which might cause strain on their bodies.
 Predetermined time systems are methods for analyzing the time spent
by workers on a particular task. One of the most widely used
predetermined time system is called Methods-Time-Measurement
(MTM).
 Cognitive Walkthrough: This method is a usability inspection method
in which the evaluators can apply user perspective to task scenarios to
identify design problems. As applied to macroergonomics, evaluators
are able to analyze the usability of work system designs to identify how
well a work system is organized and how well the workflow is
integrated.

 High Integration of Technology, Organization, and People
(HITOP): This is a manual procedure done step-by-step to apply
technological change to the workplace. It allows managers to be more
aware of the human and organizational aspects of their technology
plans, allowing them to efficiently integrate technology in these
contexts.
 Computer-integrated Manufacturing, Organization, and People
System Design (CIMOP): This model allows for evaluating computer-
integrated manufacturing, organization, and people system design based
on knowledge of the system.
 Anthropotechnology: This method considers analysis and design
modification of systems for the efficient transfer of technology from one
culture to another.

 Kansei Method: This is a method that transforms consumer’s responses to
new products into design specifications. As applied to macro-ergonomics,
this method can translate employee’s responses to changes to a work system
into design specifications.
 Systems Analysis Tool (SAT): This is a method to conduct systematic
trade-off evaluations of work-system intervention alternatives.
 Macro-ergonomic Analysis of Structure (MAS): This method analyzes
the structure of work systems according to their compatibility with unique
sociotechnical aspects.
 Macro-ergonomic Analysis and Design (MEAD): This method assesses
work-system processes by using a ten-step process.
 Virtual Manufacturing and Response Surface Methodology (VMRSM):
This method uses computerized tools and statistical analysis for workstation
design.

Weaknesses of HF&E Methods:
Problems related to usability measures are employed include the fact that
measures of learning and retention of how to use an interface are rarely
employed during methods and some studies treat measures of how users
interact with interfaces as synonymous with quality-in-use, despite an unclear
relation.
Although field methods can be extremely useful because they are conducted in
the users natural environment, they have some major limitations to consider.
The limitations include:
 Usually take more time and resources than other methods
 Very high effort in planning, recruiting, and executing than other methods
 Much longer study periods and therefore requires much goodwill among the
participants
 Studies are longitudinal in nature, therefore, attrition can become a
problem.

Three Items which Affect Ergonomics in the Workplace:
An uncomfortable work environment can affect productivity and increase
the likelihood of work-related muscle strains and eyestrain. Incorporating
ergonomics in the workplace of small business can remedy an
uncomfortable atmosphere. These simple changes help decrease stress
levels and improve employee performance.
 Computers:
Working at a computer for long periods each day increases the risk of
developing eyestrain, tension headaches, backaches and carpal tunnel
syndrome. Employees and employers can reduce physical problems with
ergonomic techniques. Positioning computer screens at least 20 inches from
eyes reduces the risk of eyestrain, as does positioning computer screens
away from bright lights and using an anti-glare computer screen.

 Work Chair:
A work or desk chair that offers maximum support greatly reduces work-related
back problems. Creating a comfortable work environment involves choosing a work
chair that supports your upper and lower back. Ample cushion in the seat reduces
hip or lower body pain. If you're typing at your desk, keeping your arms at a 90-
degree angle reduces back tension. Raise or lower your desk chair to achieve this
angle and maintain comfortable work conditions.
 Background Sounds:
Although your employer may not allow sounds from a top 40s or alternate popular
radio station, he may welcome soft, soothing sounds to help relax and ease tension.
Some employers install speakers in the walls and play classical or light sounds
throughout the workday. These sounds not only keep you relaxed and calm, they
also can fight off fatigue and keep you alert.

Benefits of a Workplace Ergonomics Process
Here are five of the proven benefits of a strong workplace ergonomics process:
1. Ergonomics reduces costs. By systematically reducing ergonomic risk factors, you can
prevent costly MSDs (Musculoskeletal Disorders). With approximately $1 out of every
$3 in workers compensation costs attributed to MSDs, this represents an opportunity for
significant cost savings. Also, don’t forget that indirect costs can be up to twenty times
the direct cost of an injury.
2. Ergonomics improves productivity. The best ergonomic solutions will often improve
productivity. By designing a job to allow for good posture, less exertion, fewer motions and
better heights and reaches, the workstation becomes more efficient.
3. Ergonomics improves quality. Poor ergonomics leads to frustrated and fatigued workers
that don’t do their best work. When the job task is too physically taxing on the worker, they
may not perform their job like they were trained. For example, an employee might not
fasten a screw tight enough due to a high force requirement which could create a product
quality issue.

4. Ergonomics improves employee engagement. Employees notice
when the company is putting forth their best efforts to ensure their
health and safety. If an employee does not experience fatigue and
discomfort during their workday, it can reduce turnover, decrease
absenteeism, improve morale and increase employee involvement.
5. Ergonomics creates a better safety culture. Ergonomics shows
your company’s commitment to safety and health as a core value.
The cumulative effect of the previous four benefits of ergonomics is
a stronger safety culture for your company. Healthy employees are
your most valuable asset; creating and fostering the safety & health
culture at your company will lead to better human performance for
your organization.

Ergonomic Risk Factors
Risk factors related to work activity and ergonomics can make it more difficult to
maintain this balance, and increase the probability that some individuals may
develop a MSD.
The major workplace ergonomic risk factors to consider are:
 High Task Repetition
 Forceful Exertions
 Repetitive/Sustained Awkward Postures
1. High Task Repetition
Many work tasks and cycles are repetitive in nature, and are frequently controlled
by hourly or daily production targets and work processes. High task repetition,
when combined with other risks factors such high force and/or awkward postures,
can contribute to the formation of MSD. A job is considered highly repetitive if the
cycle time is 30 seconds or less.

Control methods to consider:
 Engineering Controls – Eliminating excessive force and awkward posture
requirements will reduce worker fatigue and allow high repetition tasks to be
performed without a significant increase in MSD risk for most workers.
 Work Practice Controls – Providing safe & effective procedures for
completing work tasks can reduce MSD risk. In addition, workers should be
trained on proper work technique and encouraged to accept their responsibilities
for MSD prevention.
 Job Rotation – Job task enlargement is a way to reduce duration, frequency
and severity of MSD risk factors. Workers can rotate between workstations and
tasks to avoid prolonged periods of performing a single task, thereby reducing
fatigue that can lead to MSD.
 Counteractive Stretch Breaks – Implement rest or stretch breaks to provide an
opportunity for increased circulation needed for recovery.

2. Forceful Exertions
Many work tasks require high force loads on the human body. Muscle
effort increases in response to high force requirements, increasing
associated fatigue which can lead to MSD.
 Engineering Controls – Eliminating excessive force requirements will
reduce worker fatigue and the risk of MSD formation in most workers.
Using mechanical assists, counter balance systems, adjustable height lift
tables and workstations, powered equipment and ergonomic tools will
reduce work effort and muscle exertions.
 Work Practice Controls – Work process improvements such as using
carts and dollies to reduce lifting and carrying demands, sliding objects
instead of carrying or lifting, and eliminating any reaching obstruction
to reduce the lever arm required to lift the object.
 Proper Body Mechanics – Workers should be trained to use proper
lifting and work techniques to reduce force requirements.

3. Repetitive/Sustained Awkward Postures
Awkward postures place excessive force on joints and overload the muscles and
tendons around the effected joint. Joints of the body are most efficient when they
operate closest to the mid-range motion of the joint. Risk of MSD is increased when
joints are worked outside of this mid-range repetitively or for sustained periods of
time without adequate recovery time.
 Engineering Controls – Eliminate or reduce awkward postures with
ergonomic modifications that seek to maintain joint range of motion to
accomplish work tasks within the mid-range of motion positions for
vulnerable joints. Proper ergonomic tools should be utilized that allow
workers to maintain optimal joint positions.
 Work Practice Controls – Work procedures that consider and reduce
awkward postures should be implemented. In addition, workers should be
trained on proper work technique and encouraged to accept their
responsibility to use their body properly and to avoid awkward postures
whenever possible.

 Job Rotation – Job rotation and job task enlargement is a way to reduce
repeated and sustained awkward postures that can lead to MSD.
 Counteractive Stretch Breaks – Implement rest or stretch breaks to provide
an opportunity to counteract any repeated or sustained awkward postures and
allow for adequate recovery time.
 Anthropometry:
 The word ‘anthropometry’ means measurement of the human body. It is
derived from the Greek words ‘anthropos’ (man) and ‘metron’ (measure).
 Anthropometric data are used in ergonomics to specify the physical
dimensions of workspaces, equipment, furniture and clothing to ensure that
physical mismatches between the dimensions of equipment and products and
the corresponding user dimensions are avoided.

 Designing for a population of users:
 The first step in designing is to specify the user population and then to design to
accommodate as wide a range of users as possible – normally 90% of them. Well
designed products acknowledge and allow for the inherent variability of the user
population.
 In ergonomics, the word ‘population’ is used in a statistical sense and can refer to a
group of people sharing common ancestors, common occupations, common
geographical locations or age groups. A user population may consist of people from
different races (i.e. groups differing in their ancestry) or different ethnic groups
(different cultures, customs, language, and so on). For design purposes, the criteria for
deciding what constitutes a ‘population’ are functional and are related directly to the
problem at hand. If we want to design a cab for bus drivers in Chile, we require data
on the anthropometry of Chilean bus drivers. If we want to design workspaces in
private hospitals in Saudi Arabia, we need data about the European and Australian
nurses who usually work in them.

Anthropometry and its uses in ergonomics
 As a rule of thumb, if we take the smallest female and the tallest male in a
population, the male will be 30–40% taller, 100% heavier and 500% stronger
(Grieve and Pheasant, 1982). Clearly, the natural variation of human
populations has implications for the way almost all products and devices are
designed. Some obvious examples are clothes, furniture and automobiles. The
approach of ergonomics is to consider product dimensions in human terms in
view of the constraints placed on their design by body size variability. For
example, a seat should be no higher than the popliteal height of a short user and
no deeper than the distance from the buttocks to the knees.
 Body size and proportion vary greatly between different populations, a fact that
designers must never lose sight of when designing for an international market.
A US manufacturer hoping to export to Central and South America or South-
east Asia would need to consider in what ways product dimensions optimized
for a large US (and probably male) user-group would suit Mexican or
Vietnamese users; the latter belong to one of the smallest populations in the
world. Ashby (1979) illustrated the importance of anthropometric
considerations in design as follows:

 If a piece of equipment was designed to fit 90% of the male US population, it
would fit roughly 90% of Germans, 80% of Frenchmen, 65% of Italians,
45% of Japanese, 25% of Thais and 10% of Vietnamese.
 It is usually impracticable and expensive to design products individually to
suit the requirements of every user. Most are mass-produced and designed to
fit a wide range of users: the bespoke tailor, the dressmaker and the cobbler
are perhaps the only remaining examples of truly user-oriented designers in
Western industrial societies.
 Types of anthropometric data
 Structural anthropometric data :
Structural anthropometric data are measurements of the bodily dimensions of
subjects in fixed (static) positions. Measurements are made from one clearly
identifiable anatomical landmark to another or to a fixed point in space (e.g.
the height of the knuckles above the floor, the height of the popliteal fossa
(back of the knee) above the floor, and so on). Some examples of the use of
structural anthropometric data are to specify furniture dimensions and ranges
of adjustment and to determine ranges of clothing sizes.

 Functional anthropometric data:
Functional anthropometric data
are collected to describe the movement of a body part with respect to a
fixed reference point. For example, data are available concerning the
maximum forward reach of standing subjects. The area swept out by the
movement of the hand can be used to describe ‘workspace envelopes’,
zones of easy or maximum reach around an operator. These can be used
to optimize the layout of controls in panel design. The size and shape of
the workspace envelope depends on the degree of bodily constraint
imposed on the operator. The size of the workspace envelope increases
with the number of unconstrained joints.

Industrial engineering ae 481

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Industrial engineering ae 481

Similar to Industrial engineering ae 481 (20)

Recently uploaded

Recently uploaded (20)

Industrial engineering ae 481