Sarasvathi. V

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Introduction: The primary concern of ergonomics being the design of the workplace as a system so as to achieve the best possible performance from the humans consistently and continuously, an interdisciplinary knowledge in relevant fields, such as work physiology, biomechanics, psychology, engineering, systems design and cybernetics, is needed to


  • To formulate systems goals,
  • To understand functional requirements, To analyze the system,
  • To design a new system, and To implement the system.


Thus, to resolve any problem of this nature at the workplace, ergonomics is most likely to offer a set of solutions leading to


Increase in productivity of resources and efficiency in production equipment, Safe working methods,


Improved health of humans with minimization of hazards, and Design and maintenance of a comfortable work environment.


Ergonomics is defined as “that branch of science that is concerned with the achievement of optimal relationships between workers and their work environment”. It is also called as human engineering or human factors. It is derived from Greek words ‘ergon’ means work, ‘nomic’ means natural laws. It is a discipline concerned according to human needs. It deals with the assessment of the human’s capabilities and limitations such as from anatomy and physiology we learn about the structure and functioning of the human body. Anthropometry gives information on body size. Physiological psychology deals with the functioning of the brain and the nervous system.


Ergonomics deals with study of human and machine interface. Machine does not mean electrical devices but all devices. This is designed in order to create a comfortable working environment. One has to adapt both physically & psychologically to his work environment. Because of non conclusive environment nowadays people face many health issues.


The Scope of Ergonomics: The scope of Ergonomics is tremendously wide and is not restricted to any particular industry or relevance. Ergonomics move towards everything which engrosses people. Work systems, sports and leisure, health and safety all symbolize ergonomics principles if well intended. The capability of people to do their job is influenced by the person’s potential (physical and mental), the job demand (physical and mental) and the condition (physical and organizational environment) under which the person is carrying out the job.


The Objectives of the Ergonomics is to augment the efficacy with which work and other human activities are carried out and to preserve or improve certain desirable human values in the process, health, safety, satisfaction etc.,


The aim of ergonomics is to increase and conserve human health and contentment and to optimize the human performance in a system standpoint. Ergonomics is concerned with both employees’ well-being as well as organization well-being. Ergonomics aims to make certain that human requirements for safe and proficient working are met in the design of work systems. The key words are; health, comfort and performance.It will be clear already that the benefits of ergonomics can appear in many different forms, in productivity and quality, in safety and health, in reliability, in job satisfaction and in personal development.


The reason for this breadth of scope is that its basic aim is competence in purposeful activity—effectiveness in the widest sense of accomplishing the desired result without wasteful input, without error and without damage to the person involved or to others. It is not efficient to burn up redundant energy or time because inadequate thought has been given to the design of the work, the workspace, the working environment and the working conditions. It ensures that the functioning situation is in harmony with the performance of the worker. In view of these complexities it might seem that the solution is to provide a flexible situation where the human operator can optimize a purposely apt way of doing things. Unfortunately such an approach is sometimes impracticable because the more well-organized way is often not apparent, with the result that a worker can go on doing something the wrong way or in the wrong conditions for years. Thus it is necessary to adopt a systematic approach: to start from a sound theory, to set measurable objectives and to check success against these objectives.


Aspects of Ergonomics:


There are five aspects of ergonomics: safety, comfort, ease of use, productivity/performance, and aesthetics. Based on these aspects of ergonomics, examples are given of how products or systems could benefit from redesign based on ergonomic principles.


Safety – Today, everything is ergonomically oriented. However, buying just a single chair which provides good posture, balance and less stress on the body is not the adequate. To prevent musculoskeletal injuries, one must buy additional furniture components which are also responsible in decreasing stress and work related injury. Similarly, the overhead cabinets over kitchen counters in a kitchen may be lesser in depth and optimal in height so that the person working may get adequate head room and will not get hurt while bending over the counter. Ergonomic principles can help one to avoid injuries at home as well as at work.


Comfort – It is extremely important that products like chairs are designed with ergonomics in mind. The chair should be comfortable for the child, supporting his back and allowing his feet to touch the floor. In the case of task lighting for study table, some task lights are extremely bright as compared to their surroundings and may cause glare and discomfort to the user. Ergonomic principles could re-design this based on contrast principles.


Ease of use– Seated on an ergonomically designed chair and work with a computer, the height of the chair must be adjusted accordingly. It is important to place the computer monitor at a level where it does not produce stress on the eyes or the hands. The top of the screen should be ideally set just below eye level. When sitting upright, this positioning will not produce any neck, shoulder or eye stress. Similarly, microwave ovens when placed them at a height that is much below the eye level makes it difficult to check while cooking. This could be addressed with the principles of working heights in ergonomics and aptly placing it to ease the process.

 Productivity/performance– Ergonomics can potentially be used to improve productivity as well. The kitchen is typically the most used room in any house. And an efficient kitchen is typically a key point in having a happy life. There is an ergonomically correct working height for each type of work the work counters can be designed to maximize performance and reduce work stress by considering both ergonomics and productivity together.


Aesthetics – Aesthetics concerns our senses and our responses to an object. If something is aesthetically pleasing to you, it is ‘pleasurable’ and you like it. It is integration of function, usability, and aesthetics in design e.g. Switchboards may be placed at an appropriate height with the help of ergonomics principle so that they are consistent in height, therefore easy to locate and also do not become splotches in the interior elevations. Thus, letting the interior look pleasant while not being unduly emphatic on the walls.


Ergonomics is the study of the interaction between people and machine and factors that affect the interaction Purpose is to improve the performance of the systems by improving human machine interaction. This can be done by “ designing-in” 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.


Ergonomics is beneficially applied in subsequent three areas:


1.Design of Man-Machine Systems: A man-machine system is a system where one or more workmen/ human beings work in relation with one or more machines, devices or equipment. Thus a worker drilling a hole in a job or a person using a hammer to drive a nail in a wooden job (an article being manufactured is an example of a man- machine system as far as ergonomics is concerned.


Such systems could be productive systems as well as service systems such as a post office or fire fighting system or a dispensary etc. Ergonomics is applied to adapt such systems so as to provide maximum job satisfaction and comfort and minimum physiological and mental load to the operator of the system.


2.  Design of Consumer Goods and Service Systems: Ergonomics is applicable in the design of consumer goods starting from design of tooth brush and other items such as dinning set; sofa set; kitchen ware, house hold fittings table and shoes etc. Similarly protective equipment such as safety goggles, adverse weather and space clothing, gloves, crash helmets, fire fighting and industrial hazard protection and appliances etc. should also be economically sound.


3.Design of Working Environment: While designing a proper working environment for work force/workers at work, the various factors related with ergonomics such as human endurance of illumination, pollution, noise heating and ventilation should be taken into consideration. This aspect should be taken into consideration at each stage right design up to real utilization or actual service.All factors concerned with environments such as design of work benches, public transport, road systems, town and country planning, personnel, neighbourhood, as well as airports etc. should be subjected to ergonomic analysis.


System can be improved by


Designing the user-interface. It should be more compatible with the task and the user, which is easy to use and more resistant to errors.


Change the work environment that is safe and more appropriate for the task. Change the task by being more compatible with the user.


Change the way work, environment is organised to meet people’s psychological and social needs.


Work environment can be improved by eliminating vibration, noise and providing good seat, desk, and ventilation/lighting. Introduce the system/task with procedure that the people using it are already familiar with it. Work organisation can be improved if the workers are permitted to work at their own pace. Psychological stress would be reduced. Eliminate aspects of system that are undesirable, uncontrolled, un accounted for. They get fatigued easily and the people tire unnecessarily. Due to bad interface people are prone to accidents, injuries and more errors happen. This can also lead to user difficulties due to inappropriate combo of subtask that are cumbersome and unnatural. Inefficient worker produces sub optimal output. In ergonomics injury, poor quality, increased human errors are system problem and not people problem. A solution to it would be in redesigning a better system than man management.




Man –machine system (mms) always has a human subsystem, and a user interface (UI). These subsystems can further be divided into smaller and even smaller elements as necessary. Depending on the particular aim of the analysis, Human factor is a system concerned with the relationship between human beings, machines and the work environment. The objective is to obtain the optimum balance between the human capabilities and the demands of the task


The man-machine relationship is the central core of human factors: the man and the machine may perform similar functions. Both have certain capabilities and limitations.


Both the words i.e., man and machine ,which benefits the human operator and enhances the overall system performance is a primary aim of the human factors/ergonomics discipline


A few examples of man- machine systems are:


a) A key-board operator and the computer

b)  A pilot flying an aircraft


Interface between Man –Machine: When use a tool or machine we interact with it through interface (handle, steering wheel). We get a feedback via an interface (Compaq Screen). This way the interface determines how easily and safely we can use the machine.


Human machine system: System is a set of elements and there is relationship between these elements and boundary around them. System comprises of people and machine that perform a function in a specified combo and get some form of output. In ergonomics, human is a part of the system and should be fully taken into consideration at the design state. So human requirement are prime, and their requirements in general are as follows: Equipment should be usable and safe. Tasks are compatible with people expectation, limitation and training. Environment should be comfortable and appropriate for the task. Work organisation should recognise people’s social and economic needs.


Man and Machine Interaction: The performance of the worker in an industry depends upon the interaction and interrelationships of the worker with the machine/equipment and the environment. A production unit is usually a man-machine integrated system performing under an environment envelop. The environment refers to not only the ambient conditions of temperature, humidity, noise, etc.., but also the arrangement of layout facilities, display and controls. Thus human factor engineering is that endeavour which seeks to match human with the machine, equipment and facilities so that their combined output will be efficient, comfortable and safe. Complex information is processing and decision making efforts for effective control. It calls for the interaction of equipment designers with specialists in the field of work design, Physiology and biological sciences.The human subsystem, for example consists of anthropometric, physiological, perpetual, cognitive, and emotional. Sub-systems that can further are divided into even smaller elements if necessary.


Determinants of MMS System Performance


The objective of every organization to introduce ergonomics is to increase the performance at required level of quality and safety. There are several factors that determine the man-machine system performance, which are briefly described as under

(a)    Operator’s ability : it is based on two factors –selection and training of the personnel

(b)   The system design: it is also based upon two things –equipment and display and control

(c)    The system operation: it is based on three parameters that include workload, communication channel and maintainability.


A Simple Man-Machine system


After starting the machine, the man will receive certain information from the machine, either from dials, displays, etc…, designed for that purpose, or by observation of the machine itself. The man will then process this information and make decisions with regards to the actions he should take. He may manipulate controls or attend to the machine in some other way so as to affect its behaviour in the desired manner. Both man and machine are subject to certain inputs. The efficiency with which the man functions depends on environmental factors and on his own characteristics such as age, motivation, training and his experience, as well as on the efficiency with which the machine provides the information feedback and accepts control measures.




–          The man machine system may be categorized on the following basis:


(1)   Nature of man’s involvement in the system

(a)    A closed loop system

(b)   An open loop system


(2)   Degree of man versus machine control

(a)    A manual system

(b)   A semiautomatic (mechanical)system, and

(c)    An automatic system


A closed loop system requires continuous control and feed back to function successfully, e.g., a man flying a bomber plane or a fighter plane. Feedback is essential in order to correct errors, if any through continuous control. An open loop system is one which is once initiated or started needs no further controlled by man or at least cannot be further controlled, e.g.., firing a bullet from a revolver. The path of the bullet cannot be continuously controlled. A manual system is essentially a man directed system e.g., a worker cutting a mild steel bar using a (hand) hacksaw. A large variability is possible in a manual system as every worker may select a different method or motions to do the same job. A mechanical system is more complex and inflexible in nature than a manual system because it has components which are well integrated. The machine component which is power-driven and human activity is information processing decision making and controlling. An example of mechanical system is a driver driving a car. An automatic system is a still more complex system in which all operational functions are performed by automatic devices. Operational functions are sensing, information processing and decision making and action. The man does the tasks of monitoring, programming the function, maintenance and upkeep. An automatic telephone exchange is an example of this system. A perfectly reliable automatic system does not exist at present.


Characteristics of a Man –Machine System


(1)   The man machine system consists of the man, the machine and the environment.

(2)   This system is artificial and is specifically developed to fulfil specific purpose

(3)   It has specific inputs and outputs which are appropriately balanced

(4)   It is variable in size and capacity and is dynamic in performance

(5)   Subsystems of man machine system interact and affect each other

(6)   The man machine system becomes more efficient when output results are fed back to the system

(7)   Environmental factors influence the performance of the system

Man versus Machine:


Man is generally better in his abilities to:


1.Be creative

2.Develop entirely new solutions

3.Make subjective estimates and evaluation

4.Apply principles to solutions of varied problems

5.Reason inductively, generalizing from observation

6. Select alternative modes of operation if certain modes fail

7. Draw upon varied experience in making decisions. Adapt decisions to situational requirements and act in emergencies

8. Store large amounts of information over long periods of time

9. Sense unusual and unexpected events in the environment

10. Sense very low levels of certain kinds of stimuli; visual, auditory, taste etc.

11. Recognize pattern of complex stimuli which may vary from situation to situation


Machines are generally better in their abilities to:


1.    Machines can perform many different operations simultaneously

2.    They can apply huge amounts of force suddenly or smoothly

3.    Be extremely precise

4.    Sense stimuli that are outside man’s normal range of sensitivity such as X-rays radar wavelengths and ultrasonic vibrations

5.    Store coded information quickly and in substantial quantity.

6.    Retrieve coded information quickly and accurately when specifically requested

7.    Make rapid and consistent responses to data input

8.    Perform repetitive activities reliably

9.    Maintain performance over extended periods of time

10.   Maintain efficient operations even in those environment under which man cannot work



(i) Design of information displays

(ii) Design of controls

(iii)  Environmental factors


Relation between safety and technical risk:


Technical safety is very important ability of subject/machine technology operations to perform this function without any hazardous situations for persons or environment hazardous situation in such circumstances in which a person is exposed to a hazard


Technical risk is defined as a combination of the probability of occurrence of harm and the severity of the harm/weight factor risk management or in other word control of risk is based on three points


(i) Identification of hazardous

(ii)  Risk analysis

(iii)Reduction or elimination of risk


Complex method of risk evaluation in the work place: This method of the risk evaluation directly in the workplace was developed in the section machine safety working group for mechanical, physical and chemical risks .Such a method must be very simple and easy several components of the whole system can be neglected and other components are very important and necessary system in this meaning is one more complex of components which perform various functions


Goal of work system design and the idea of main in ergonomics: Basic goal of work system design is the optimization of the entire work system. In the sense of main objective of ergonomics work system are to be suitably arranged for both human and economical purpose. Thereby economy is determined by the best possible proportion of input (eg: finished products, service) ergonomics is based on the assumption that rationalization and humanization goals work complementary to each other ergonomics considers the technology , the organization and the personnel in the context of human work. In doing so, ergonomics distinguish itself from predominantly human being referred disciplines by including technical.




Compatibility between the user and the rest of the system can be achieved at a number of levels namely, Biomechanical, behavioural, Physiological, cognitive levels etc. To assess the demands placed by the technology and environmental constraints weigh them against the capacity of the user. Ergonomic entropy is a disorder due to lack of compatibility in some or all of the interaction.


Reasons for incompatibility:


o   Requirement for optimum function was never considered at the designer stage.

o   Inappropriate task design

o   Lack of prototyping


Interaction between work systems: There are 6 combinations of man, machine and environment. They are

Human vs Machine: This is the one which man gives to the machine. Control system of machine, Application of force

Human vs Environment: Humans emit noise and carbon- di -oxide .

Machine vs Human: Feedback and display information. This is the output that a man gets from the machine. Eg: The vibration from the machine and acceleration from the machine

Machine vs Environment: Change the environment. Example -the noise of the machine, the gas or heat that is emitted from the machine.

Environment vs Human: Environment influence the human ability to interact with the machine and remain as the part of the work system. The noise, smoke, heat that comes from the environment can affect the human in both physical and psychological aspects.


Environment vs Machine:


Affect the function of the machine. Over heat/freezing of the component These are the simple basic work system. This system is applicable to one person, machine and an environment; all the 6 direction is possible. Of the six 4 involves human: human vs machine and environment, Machine vs Human and environment. Each of these interacts directly or indirectly with others. Application of ergonomics enables it to function better by improving the interaction between the user, and machine.


Conclusion: Ergonomics is the systematic study of people at work with the objective of improving the work situation, the working conditions and the tasks performed. The emphasis is on acquiring relevant and reliable evidence on which to base recommendation for changes in specific situations and on developing more general theories, concepts, guidelines and procedures which will contribute to the continually developing expertise available from ergonomics.




Web links


  • https://en.oxforddictionaries.com/definition/aesthetic
  • https://www.merriam-webster.com/dictionary/anthropometry
  • www.dictionary.com/browse/biomechanics
  • https://en.wikipedia.org/wiki/Cybernetics
  • https://www.collinsdictionary.com/dictionary/english/ergonomics
  • https://en.wikipedia.org/wiki/Hazard
  • https://www.healthline.com/health/musculoskeletal-disorders
  • https://www.collinsdictionary.com/dictionary/english/physiology