CHAPTER 1 INTRODUCTION TO ERGONOMICS AND ANTHROPOMETRY 1.1 ERGONOMICS: Ergonomics is an approach which puts human needs at the focus of designing technological systems. The name “Ergonomics” comes from the Greek word “ergon ” which means work and “nomos ” which means law. The core sciences from which ergonomics is drawn are: Psychology: It is concerned with human information processing and decision-making capabilities. Anatomy: The contribution of basic anatomy lies in improving physical 'fit' between people and the things they use. Engineering: it is related with designing of technical products and services by taking human characteristics into account. Ergonomics comes into everything which involves people. Work systems, sports and leisure, health and safety should all embody ergonomics principles if well designed. The aim behind having a product with ergonomic design or an ergonomic workplace is to ensure that the human working over there is safe and comfortable to be in the same position for a longer period of time. For ergonomics, human is a part of a system and must be fully integrated into it at the design stage. Human 1
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CHAPTER 1 INTRODUCTION TO ERGONOMICS AND
ANTHROPOMETRY
1.1 ERGONOMICS:
Ergonomics is an approach which puts human needs at the focus of designing
technological systems. The name “Ergonomics” comes from the Greek word “ergon”
which means work and “nomos” which means law. The core sciences from which
ergonomics is drawn are:
Psychology: It is concerned with human information processing and decision-making
capabilities.
Anatomy: The contribution of basic anatomy lies in improving physical 'fit' between
people and the things they use.
Engineering: it is related with designing of technical products and services by taking
human characteristics into account.
Ergonomics comes into everything which involves people. Work systems, sports and leisure,
health and safety should all embody ergonomics principles if well designed. The aim behind
having a product with ergonomic design or an ergonomic workplace is to ensure that the
human working over there is safe and comfortable to be in the same position for a longer
period of time.
For ergonomics, human is a part of a system and must be fully integrated into it at the
design stage. Human requirements are, therefore, system requirements, and can be stated in
general terms as:
Equipment that is usable and safe.
Environment that is comfortable and appropriate with the task.
Tasks those are within people’s limitations.
The implementation of ergonomics in the system design should make the system work better
by eliminating aspects of systems which are undesirable, such as,
Fatigue
Accidents, injuries, and errors.
User difficulties.
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1.1.1 DOMAINS OF ERGONOMICS:
Domains of specialization of ergonomics can be classified as follows:
1. Physical ergonomics is concerned with human anatomical, anthropometric,
physiological and biomechanical characteristics.
2. 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.
3. Organizational ergonomics is concerned with the optimization of sociotechnical
systems, including their organizational structures, policies, and processes.
1.1.2 APPLICATIONS OF ERGONOMICS:
Ergonomics is successfully applied in fields of:
i. Aerospace
ii. Product design
iii. Transportation
iv. Nuclear and virtual environments.
v. Designing of workplaces.
1.2 ERGONOMICS IN AUTOMOBILES GOT TO INCLUDE POINTS
from design of automobile interiors
It is essential that the ergonomic input to the vehicle takes place throughout the design
process. For this very purpose, most of the automobile manufacturing companies employee
ergonomists. Ergonomists, usually, follow an inside out approach for the design. By
following this approach, the ergonomist would get clear idea about the size, number and age
of the future occupants along with their comfortable posture. This would then help the
ergonomist to design the display and control interfaces with the knowledge of hand and eye
ranges. The exterior of the vehicle would then be designed.
As far as an automobile design is concerned, an ergonomist has to work on
following aspects:
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Design of driver’s seat
Design of control systems
Design of hand lever and steering.
Ergonomists have had to find methods of communicating ergonomic information to
those who need to use it. There are a wide range of standards, guidelines and
recommendations available in many areas of ergonomics that are pertinent to automotive
design. The Society of Automotive Engineers (SAE) in the US has been particularly active in
the generation of such Standards. The most relevant to the ergonomist are:
SAE J826 H-point (ISO 6549)
SAE J1100 Seating reference point
SAE J1100 H-point travel path
SAE J1517 Driver selected seat position
SAE J941 Eyellipse (ISO 4513/BS AU 176)
SAE J1052 Driver and Passenger head position contours
SAE J287 Hand controls reach envelopes (ISO 4040/BS AU 199).
Other tools which may be used involve use of various soft wares like CAD,
MANIKINS, and 2D package drawings. These MANIKINS are basically used to examine
occupant accommodation. The 2D package drawings often provide the first visualizations of
the proposed vehicle occupants. They are produced after the product planning stage, when the
market specification has taken place and the basic parameters of the vehicle are known.
1.2 ANTHROPOMETRY
The word Anthropometry has been derived from the Greek words “anthropos” meaning man
and “metron” meaning measurement of human body. Anthropometric data are used in
ergonomics to specify the physical dimension of workspaces. It can be divided into two
types:
Static anthropometry
Dynamic anthropometry
Static anthropometry is concerned with the measurement of human subjects in rigid,
standardized positions (e.g. static arm length being equivalent to its anatomical length). Static
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anthropometric data are used in designing equipment for the workplace where body
movement is not a major variable, e.g. seat breadth, depth and height.
Dynamic anthropometry is concerned with the measurement of human subjects at work
or in motion (e.g. functional arm reach is a factor of the length of the upper arm, lower arm
and hand, as well as the range of movement at the shoulder, elbow, wrist and fingers).
Dynamic anthropometric data can be used to establish control locations using reach
envelopes for the hands and feet and locations of head restraints, seat belts.
For any design involving the use of anthropometric data, 4 set of constraints have to
consider. They are as follows:
Clearance: Clearance means provision of sufficient space around the work-place.
Reach: Reach constraint refers to the ability to operate controls from a comfortable
position.
Posture: Posture means the way in which the driver
Strength : Strength is concerned with the application of force in operation of controls.
1.2.1 APPLICATIONS OF ANTHROPOMETRY:
Anthropometric studies are used in the design of modern aircraft, preparation for cosmetic
surgery, etc. When paired with ergonomics, it is used to craft office workstations, aircraft
cockpits, and home furniture. Anthropometry is also used in safety design, specifically for
infants and children.
1.3 ANTHROPOMETRY IN AUTOMOBILE DESIGN
In case of automobile design, anthropometric factors are used for occupant accommodation.
Various anthropometric factors have to be considered, which may include,
i. Sitting height
ii. Sitting eye height
iii. Sitting shoulder height
iv. Thigh clearance, etc.
In order to establish statistical concepts that determine human variability, a large amount of
data relating to various dimensions of different humans is carried out. With the help of this
data a normal distribution curve is obtained.
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A normal distribution is fully defined by its mean and standard deviation—if these are known
any percentile may be calculated without further reference to the original measurements of
individual people.
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CHAPTER 2 DESIGN OF DRIVERS SEAT
Seat is an important part of car. Drivers spend great deal of time on the seat. The purpose of a
seat is to provide stable bodily support in a posture that is:
(i) Comfortable over a period of time;
(ii) Physiologically satisfactory;
(iii) Appropriate for driving.
Comfort will depend upon the interaction of seat characteristics, user characteristics.
Seat characteristics include seat dimensions and seat angles while user characteristics include
body dimensions, body aches and pains.
2.1 Anthropometric factors related to user characteristics:
User characteristics 1
1) Seating height: Vertical distance from the sitting surface to crown of
the head. It is used to determine overhead clearance.