A2 Technology

Product Design

Systems and Control Notes

DT4 - Exam

Ergonomics

2

What is ergonomics?

• Ergonomics is “the study of the interaction of man and his environment”

• From the Greek ‘Ergon’ work and ‘nomos’ meaning natural laws. In other words the natural laws of humans doing work.

• Ergonomics can be divided into the following areas:– Physical and Psychological ergonomics– Cognitive ergonomics and– Organisational ergonomics

Physical Ergonomics

• How the body responds to physical and psychological stresses.

• For example – ‘physical’ ergonomics means a product is

designed so that it is not too heavy, or uncomfortable or too big or too small, or designed to minimise this physical stresses. This arm of ergonomics is called ANTHROPOMETRICS.

Psychological Ergonomics

• For example – ‘psychological’ ergonomics means a product

is designed considering how the user will interact with it and use it. Can they understand its use intuitively. Psychology is the study of behaviour.

Cognitive Ergonomics

• …also known as engineering psychology, concerns mental processes such as perception, attention, cognition, motor control, and memory storage and retrieval as they affect interactions among humans and other elements of a system.

• Relevant topics include mental workload, vigilance, decision making, skilled performance, human error, human-computer interaction, and training.

Organisational Ergonomics

• ... or macro ergonomics, is concerned with the optimisation of sociotechnical systems, including their organisational structures, policies, and processes.

• Relevant topics include shift work, scheduling, job satisfaction, motivational theory, supervision, safety culture, teamwork, telework and ethics.

Anthropometrics

• From the Greek ‘anthro’ man and ‘metrics’ measurements

• Literally means the measurement of humans.• Today, anthropometry plays an important role in

industrial design, clothing design, and architecture, where statistical data about the distribution of body dimensions in the population are used to optimize products

Anthropometrics

• Imagine you are designing a computer desk

• You need to study the interaction of the person with the computer (ergonomics) and then the sizes of people who use the desk (anthropometrics).

• Both of these pieces of information will help you draw up a specifcation.

Anthropometrics

Anthropometric table

Female Male

                                                       

  5% 50% 95% 5% 50% 95%

                                                       

A 690 743 795 739 795 850

B 181 226 266 188 235 274

C 406 439 479 447 482 520

D 438 478 525 458 499 544

E 540 585 637 569 616 665

F 352 388 428 395 434 476

G 474 513 558 515 559 605

Anthropometric table

• The data was gathered by measuring 1000 or more people and recording the frequency of each piece of data.

• A frequency graph can then be plotted for each piece of data, for example seated height F

• The distribution of the graph will have a bell shaped curve which is called a normal distribution curve.

Normal distribution curve

5% 50% 95%

Frequency graph for seated height F

Frequency

Heights

Normal distribution curve

5% 50% 95%

If you design for the MEAN you only design for 50% of the population.

Frequency

Heights

Mean

Normal distribution curve

5% 50% 95%

Design for 90% of the population means your product will be suitable for 90% of people. So you use the 95% percentile figure to include in your specification

Frequency

Heights

Normal distribution curve

25% 50% 75%

Sometimes it isn’t possible to design for 90% of the population as the extremes maybe too far apart. In this case you can design for 50% of the population, but between 25th and 75th percentile.

Frequency

Heights

Ergonome

• You can make a model of a 2D person to help guide your designing

• A word file has been created of a 50th percentile adult man

• Cut him out assemble him and try him on scale drawings

• He is 1/10th full scale.

Useful sites and further reading

• http://www.ergonomics4schools.com/lzone/workspace.htm