Introduction to Ergonomics

Introduction to Ergonomics

• Ergonomics comes from the Greek words "ergo" (work) and "nomos" (rules/laws)
• Ergonomics is the scientific study of interactions between humans and other system elements
• It is a design profession using theory, data, and methods to improve work systems involving humans/operators

Alternative Names for Ergonomics

• Man-Machine-Environment System
• Human Factors Engineering
• Human Engineering

Ergonomics vs. Agronomy

• Ergonomics and agronomy should not be confused; agronomy relates to crop sciences

Focus of Ergonomics

• Ergonomics considers the machine/job, operator, and working environment as interconnected elements
• These elements form a complete system that impacts work performance

Working Environment Considerations

• Ergonomics considers workspace, controls, ambient environment, noise, dust, vibrations, smoke, gases, light and safety
• Ergonomics applies principles from medical and engineering sciences to address human factors within a task

Definition of Ergonomics

• Human-factors engineering applies information about human factors to design safe, comfortable and effective tools, machines, systems, tasks, jobs, and environments
• Ergonomics focuses on people and system elements to optimize well-being and overall performance
• International Ergonomics Association defines ergonomics as a scientific discipline and profession

Purpose of Ergonomics

• Ergonomics designs and engineers human-machine systems to enhance human performance
• Human factor ergonomics designs, tests, evaluates, and manages human system interactions based on compatibility standards

Human Machine Interaction

• Human factors/ergonomics seeks to understand interactions between humans and system elements
• It is a profession applying theory, methods, and principles to optimize well-being and system performance

Operator-Machine-Environment System Approach

• Humans have limitations compared to machines but possess advantages in intelligence and decision-making
• The operator is central and uses senses to perceive the environment, then makes decisions and acts for desired outputs
• New tasks lead to slow decision-making, while routine tasks enable quick, accurate decisions, while stress impacts operator success

Machine Characteristics in Ergonomics

• Machine characteristics like controls, displays, power, speed, seat, and safety features are involved
• Workspace, control layout, and display arrangement affect operator capability
• Tractor seats prioritize operator comfort and easy control access (brakes, steering, gears, clutch)

Ergonomics and Environment

• Ergonomics applies “environment” to mean task and performance context
• Factors include ambient conditions like noise, vibrations, dust, smoke, and field conditions

Advantages of Humans vs. Machines

• Machines are much faster, reaching consistent levels, whereas humans have a quick reaction time of 0.05 seconds, with 2.0 hp for 10 sec, 0.5 hp for few minutes, 0.2 hp for continuous day of work.
• Machines excel in routine, repetitive and precise tasks, while humans are not reliable and need to be monitored by machines.
• Machines use multi-channel activities, while humans depend on single-channel tasks.
• Machines perform best for literal reproductions, while humans have large memory with multiple access with principles and strategies.
• Machines make poor error connections with fast, accurate computation, while humans are slow subject to error
• Humans have wide energy range(10^12) and variety of stimuli dealt with by 1 unit, better pattern detection, and ability to detect signals against high back ground noise.

Ergonomics: Machines

• Machines can be insensitive to extraneous stimuli and have ideal consistency for routine, repetitive, and precise tasks.
• Machines are good at deductive reasoning, fast accurate computation, and can be custom-designed to be insensitive to extraneous stimuli.
• Machines' overload reliability is sudden breakdown
• Machines are more specific and consistent

Ergonomics: Humans

• Humans have large memory, multiple access, and perform well with principles and strategies.
• They have good inductive reasoning and can deal with unpredicted and unpredictable situations.
• Humans' overload reliability is gradual degradation and their manipulative abilities have great versatility.

Ergonomics Defined

• Ergonomics designs equipment/workplaces to fit the worker by studying equipment and devices best suited for human abilities.
• Ergonomics considers the physical environment, tools/technology, workstation design, job needs, and body loading

Goal of Ergonomics

• Objective involves improving work performance, comfort, and safety by aligning workplaces with workers' capabilities
• If ergonomics is ignored, performance suffers, work time decreases, and workplace effectiveness diminishes
• Ergonomics contributes to solving safety, health, comfort, and efficiency related issues

Ergonomics in Agriculture

• In developing nations like India, there is a large farming workforce and a reliance on human power
• Human workers operate animal-drawn equipment, tractors, and self-propelled machines
• Ergonomics in agricultural machinery is important since fatigue affects operator performance
• Applied ergonomics in agriculture improves output, productivity, efficiency, work duration, comfort, and safety for farm workers

Ergonomics : System Goals

• Ergonomics goals include productivity, performance, safety, comfort, and ease of use
• Aesthetics is another key area

Ergonomics : Principles

• Physical ergonomics focuses on body interaction with tools and its effect on posture and musculoskeletal health
• Cognitive ergonomics studies how the mind processes information related to motor functions and workload
• Organizational ergonomics optimizes workplace, teamwork, performance assessment, and quality management

Basic Components : Ergonomics

• Ergonomics considers the effects of the human, machine, and environment on the complete system

Ergonomics : Human Characteristics

• Human components include senses for awareness, processors for information and effectors for physical role
• Human factors are the sensing of right, hearing, touch, taste and smell
• Elements of information processor include joints, muscles, memory and brain to act as the information processing system.
• Hands, feet and voice are the three primary effectors.

Machine Elements :Ergonomics

• Machine components include displays for status/working information and controls to allow human control
• machine components are the components that humans control for action

Local Environment : Ergonomics

• Space and conditions where work occurs, including;
  • Workspace: The three-dimensional space that it is being carried out
  • Physical environment: Local environmental conditions
  • Work organisation: Organizational structure of physical work

Ergonomics : Objectives

• Goals include improving performance, reducing errors, increasing safety, and enhancing ease of use
• Objectives also cover reducing fatigue, physical stress, improving the work environment, increasing user acceptance, and improving aesthetic appearance

Ergonomics : Improving Efficiency

• Ergonomics aims to improve reliability, reduce maintenance, minimize labor/training, enhance system efficiency, and cut production costs

Role of Ergonomics

• Technology includes all systems, knowledge, processes, and devices for creating and operating technological artifacts
• Engineering involves design to meet constraints like cost, reliability, safety, and environmental impact
• Government, laws, regulations and politics are engineering constraints
• Ergonomics uses data on human behavior, adaptations, limitations, and other human characteristics

Ergonomics : Design Elements

• Ergonomics is about applying human factors data to design productive, comfortable, and effective tools, machines, systems, tasks, jobs, and environments

Basic Ergonomics Issues

• Design and development include human characteristics and information presentation/communication
• There are elements of display/control; workplace/equipment; and environmental design
• System features, work design, organization, health, safety, and social/economic impact are also considerations

Factors of System Development : Anthropometric, Biomechanical & Physiological Factors

• Design accounts for different human body sizes
• Utilizes right anthropometric tables for specific populations and the body joints maintains neutral position
• manual work maintains closer contact to the body
• Avoiding forward bending or twisted trunk postures and the sudden movements and force exertions that may arise
• Ensures there is a worker variation in posture and movement
• Limits the duration of continuous muscular efforts
• Provides sufficient length and spread over the current task
• Avoids energy consumption for each manual task

Factors of System Development : Posture

• Sitting and standing alternates with standing, sitting and walking activities -Work height is dependent to the task
• Adjustable work table and chair ( Height of the seat and backrest)
• Limited chair adjustment possibilities
• Provision of good seat adjustment
• Foot rest where the work height is fixed
• Work will be avoided above the shoulder or hands behind the body
• Excessive reaches is avoided
• Enough area for legs to move appropriately
• Sloping work surface for reading jobs
• Combined sit-stand workplaces

Factors of System Development : Tools

• Handles of tools should be bent to allow work with straight wrists for efficiency

Factors of System Development : Material Handling

• Manual displacement of loads is maintained
• Optimum lifting conditions are achieved
• Avoiding people lifting about 23kg
• The inclusion the NIOSH methods can be used to asses the jobs
• Ensuring the fitting of handgrips to the loads
• Single individual may be employed to life and carry different tasks.
• Employ mechanical aids for lifting and carrying
• Limiting the load limit with the recognized guidelines
• Hold the load close to the body
• Limit the pulling and pushing forces
• Adequate trolleys for handles and handgrip.

Factors of System Development : Tasks and Jobs

• Ensuring the composition of one of multiple different tasks per job
• Allocating tasks for the allocation of people and machines
• Inclusion of performing the tasks that may contribute to the resolution on the problem.
• Alternate the difficult jobs with easy tasks
• Giving the workers autonomy to decided on how jobs may be executed
• Allowing effective communication between worker
• Allow sufficient material required to control the given assignments
• Allow the inclusive participation of the part group in management decision processes
• Enabling the workers to access enough opportunities to return.

Factors of System Development : Information & Control Design : Information

• Implement an appropriate method of information display
• Maintain simple information display
• Prevents the character confusion
• Ensures accurate character and letter size
• Avoid using all texts with capital letters
• Select familiar typefaces font
• Maintain accurate and consistent text with the appropriate background contrast
• Makes sure that all diagrams are relatively easier to interpret
• Implement pictograms with proper use.
• Use sound signal with adequate amount or sound signal for purposes

Factors of System Development : Information & Control Design : Control

• Maintains appropriate sense if touch used back between controls
• Maintains differences between the distinct characteristics between each other to be clear
• Maintains the consistent location of control
• Comply the requirements with control display
• Maintains the control suitability with the task
• Consistent control movements when compared with certain human requirements
• Clear control objectiveness
• Controls in each reached within comfortable range by each people
• Identifying symbols and labels for each control purposes
• Limited of the different designs

Factors of System Development : Information & Control Design :Human- computer interaction

• Adequate human computer dialogue for each task intention
• The dialogue self descriptive and easy to control
• Dialogue conforms to human’s part of the user
• The dialogue error-tolerant and user learning
• Restricted command language for each users with expertise
• The menu will provide detailed information with little experience on each case
• Maintaining the type of menu with the right degree of the user
• Implementing appropriate layout that best select the best key for each keyboard
• Maintain appropriate logical layout for keypad use
• Maintain the limited number of work function keys.
• Comply with the potential limitations of speech from each human with the proper computer dialogue that is implemented
• Adequate use of touch screen to provide operations for the experienced workers

Factors Concerning Environment : Noise and Vibration

• Maintaining noise levels below 85 dBA
• Maintaining ample separation distance between the workers the noise
• Maintains the usage of ceiling that allows noise absorption
• Adequate Use of Acoustic screens
• Implement hearing conservation measures that fits each user
• Monitoring personnel against exposure workers to noise / vibrations
• Recognize uncomfortable and damaging causes that cause body vibrations
• Resolving the vibration issue at its source
• Appropriately maintain regular machines with appropriate intervals
• Maintaining the transmittal of adequate source for each vibration

Factors Concerning Environment : Illumination

-Normal activities with lights ranging 200-800 lux -Avoid large visual differences among most fields

• Brightness between task areas, maintaining the close surroundings and surrounding
• Makes sure that the information is easy when it comes to legibility
• Ambient lighting is combined with localized lighting
• Screen all light accurately
• Prevents the reflection of light , shadows and flickers to prevent tube fluorescents

Factors Concerning Environment : Climate

• Allow climate self control operations
• Monitor physical job related with atmospheric temperature.
• Make sure that atmospheric air is dry when it turns humidity
• Preventing drafts
• Materials and surface are adequate cold and too hot to the the appropriate degree
• Physical needs is maintained or adjusted with climate
• Prevents undesirable and radiation.

Human Performance : Ergonomics

• Machinery application, physiology, and psychology fatigue/stress are very important
• There exists numerous factors that causes stress for workers like workload, time, ambient climate, pollution etc
• Chance of accidents may include psychological fatigue e.g, space, overload of information overload
• Ergonomic studies such as stress can be measured by the operator’s stain ( heart rate, respiration, fatigue.
• Stresses such as eyes and work are included in measurement of physiological for mental strain with Ergonomic design

Factors of Measurements: Performance

• Workers are integral part of environment of machines and appropriate physical activity is required
• Heart rating and respiration is a critical indication for humans which is critical in stimulation, fatigue , and energy
• Dependent parameter is useful because It indicates human- workload
• HR is measured with 2.3 mm to measure nature
• Respiration depends on work volume, it may measure workload with inspiration activities.
• This will measure oxygen by calculating energy expenditure, work is categorized from light to heavy depending on HR ( oxygen measurements )
• Relative load(rl) measures hr’s VO2 max is volume

Heart and Work Rate : Ergonomics

• Heavy rate for human work force is 1-1.5 consumption for minutes with the heavy rate beats up to 110

Ergonomics : Discomfort

• Discomfort and postures are the most critical reason that causes the most effect which will result in reducing of the efficiency when regarding safety of employers such that
• Overall discomfort of the different body parts are measured with techniques that score the pain of of each of pain score.

Psychological Effects

• In particular operations a large level of safety such accuracy is needed which impacts neuro/sensory activities that results in stress due to brain or hearing.
• As a result poor work is followed and it leads to accidents or headache,
• These measurements require measurement on errors time or other different level activity

Performance Reliability :Ergonomics

• Performance measures the quantitative parameters for components or its parameters
• This measurements determines its function over time and conditions
• Reliability measures average operating time as consistent of errors

Potential Flaws : Human Performance

• A potential fault is determined by the lack of proper parameters completely and is distinguished

Components in Series:

• If the system has faults the component with best potential should be chosen.

Reliability of System : Ergonomics

• Most the reliability of the system relies on a product and must connect in series

Parallel Components : Ergonomics

• Most components in such case must run parallel so that it is working in each stage which results in better service.
• The system might face damage to failure of system

Information : Ergonomics

• All senses are sensitive with light, energy, pressure
• Processing consist of primary output

Sensors

• The human sensors for various activities are as follows:

• Eyes
• Ears -skin
• Nose
• Tongues

Processing Information

• All human must feel and then be capable of action/ reaction. Thus eye act with receiving action code in electro neural activity.

Information Analysis : ERgonomics

• All incoming process should analysis must depend on coming inputs
• Storage provides stimuli and long to short term memory
• Output process responds to input for stimulation

Bit Measurement : Ergonomics

• The amount unit is measured through a binary unit and is determined with equally likely alternatives:

Stimulus : Ergonomics

• Human requires senses that it receives via different sources such as shape, pressure and visual

Dynamic/ States : Ergonomics

• There exist two type

• Changes in time e.g. fuel gauge
• Fixed e.g. traffic laws

Information for Different Indicators:

• Quantitative measurements e.g. temp
• Qualitive change for different indicator
• Status to represent condition e.g. OFF
• Signal e.g beacon
• Representational charts
• Traffic lights

Sensors

• There are visual, audible and other different traffic systems

Display Method

• Use the visual presentation where the message has complex long duration
• Audio will represent when system or simple and call to action
• The visual system represents when the operator is overburdened

Three categories: Ergonomics

• 3 categories include visual, tactile and auditory
• Visuals in specific allows greater skill to be applied
• Qualitative aspects determines approximate changes or aspects.
• There exists 3 ways to measure Qualitative

• To convey the details status of range and range numbers.
• maintain the scale number
• Observe trade

Signals and Lights

• Each system allows beams. For the signal there is detection which accounts to color etc

Representations & Alphanumeric

• These allows object in the area with illustrations to convey each detail
• Effectiveness depends on literacy
• It is important to implement symbols with the different shapes and styles

Sound : Auditory Display

• Display is based on sound which can be determined
• The level can be distinguished through log with reference to pressure with the sound

When use sound : Auditory Display

• The sound use is best for simple ,short actions
• Illumination may make it use a vision
• Operator will move away
• A form of audio visual systems , such as radio , alarm etc.

Different Senses : Tactual Display

• The tactual is based on skin senses: cutaneous touch
• Braille for sensory impaired are of different shapes texture and size

Speech Analysis

• Senses and meaning through audio coded messages
• Information which leads to a talker depending on speaking ability
• Each situation needs to be looked for communication for people with all needs to take communication e.g. telephone

Potential Distortions

• Frequency - Filter
• Amplitude and volume

• Knowledge is critical for making decision

The Message : Ergonomics

• In all weather it is useful to build in ways to determine if there issues

The vocabulary

• Use simple and known words
• Simple wording helps avoid wrong context

The Talker

• The ability is depends on speaker e.g Tv host

Distortions with Media

• All electronics communication can lead to problems such
• Frequency for filtering -Amplitude

Noise

• Noise can affect equipment distance leads to sound
• To avoid use with
• earplugs to decrease volume sensitivity
• Training for communication
• Focus on one stimulus.