ERGONOMICS KINAESTHESIA ERGONOMICS l STUDY OF HUMAN BEINGS

ERGONOMICS KINAESTHESIA

ERGONOMICS l STUDY OF HUMAN BEINGS IN THEIR WORKING ENVIRONMENT l ERGONOMICS INVOLVES: l MAN-MACHINE l MAN-ARTIFACT RELATIONSHIP

l IN ORDER TO ACHIEVE MAXIMUM EFFICIENCY OF MAN-ARTIFACT SYSTEM, THE DESIGN MUST BE CONSIDERED AS A WHOLE.

There is a close relation between man and artifact l DISPLAY: Gives information about a situation. It is information carried out to the human being (eg. Computer screen). l MAN: Receives information through the sensory channels. (eyes, ear, nose, tongue, skin) l CONTROL: Is manipulation, control changes the situation. (switch on/off lights)

A “Closed Loop System” DISPLAY MAN ARTIFACT CONTROL

l IN THIS SYSTEM, MAN IS COMPLIMENTARY TO THE ARTIFACT l MAN – DISPLAY – CONTROL - ARTIFACT l THESE ALL AFFECT EACH OTHER

KINESTHESIA l THIS IS THE SENSE THAT LETS YOU KNOW ABOUT THE POSITION OF YOUR BODY AND LIMBS IN SPACE l It is the ability to feel movements of the limbs and body l THIS IS HOW YOU CAN MOVE WITHOUT MONITORING BY VISION

KINAESTHETIC RECEPTORS • THESE ARE SMALL STRUCTURES SITUATED WITHIN THE MUSCLES l The kinaesthesis receptors are located throughout the muscles, tendons , and joints of the body. These sensors inform us of the relative positions and movements of our limbs and of different parts of our body.

l Typing is a motor skill, and feedback from the kinaesthetic receptors located in the fingers, arms, shoulder muscles, and joints is valuable information for the typist or keyboard operator. l This is because it allows him or her to be able to sense where the fingers ought to be placed without engaging in a conscious act.

A DECISION CAN BE MADE AUTOMATICALLY, OR THROUGH REASON OR LOGIC l CENTRAL NERVOUS SYSTEM: Considers brain and spinal cord. l If an action is reasonable / logical it is connected with the brain. l If it is a reflex action this is connected with the spinal cord.

DESIGN OF ARTIFACT INCLUDES: l 30% FITTING MAN TO THE ARTIFACT; IN ORDER TO HAVE AN EFFICIENT MOOD, SUCH AS CHOOSING THE PEOPLE TO USE THE ARTIFACT l 70% FITTING THE ARTIFACT TO MAN; MAKING THE ARTIFACT SUITABLE FOR A LARGE RANGE OF PEOPLE. l WE TRY TO SATISFY 90% OF THE POPULATION.

FIVE FUNDAMENTAL FALLACIES l 1. THE DESIGN IS SATISFACTORY FOR METHEREFORE IT WILL BE SATISFACTORY FOR EVERYONE ELSE. l 2. THIS DESIGN IS SATISFACTORY FOR THE AVERAGE PERSON- THEREFORE IT WILL BE SATISFACTORY FOR EVERYONE ELSE. l 3. THE VARIABILITY OF HUMAN BEINGS IS SO GREAT THAT IT IS NOT POSSIBLE TO CATER IT IN ANY DESIGN. BUT SINCE PEOPLE ARE WONDERFULLY ADAPTABLE, IT DOESN’T MATTER.

FIVE FUNDAMENTAL FALLACIES l 4. ERGONOMICS IS EXPENSIVE AND SINCE PRODUCTS ARE PURCHASED ON APPEARANCE AND STYLING, ERGONOMIC CONSIDERATIONS MAY CONVENIENTLY BE IGNORED. l 5. ERGONOMICS IS AN EXCELLENT IDEA, I ALWAYS DESIGN ACCORDING TO IT, BUT I DO IT INTUITIVELY AND RELY ON MY COMMON SENSE SO I DONT NEED ANY TABLE OF DATA.

EMPATHY l IS AN ACT OF INTROSPECTION OR IMAGINATION BY WHICH WE MAY ‘PLACE OURSELF IN ANOTHER PERSON’S SHOES’.

CRITERION SEAT HEIGHT l IS A STANDART OF JUDGEMENT WHERE THERE IS A MATCH BETWEEN THE ARTIFACT AND THE USER.

Popliteal Height: THE VERTICAL DISTANCE FROM THE HEALS TO THE BACK OF THE KNEES

CONSTRAINT l IS A MEASURABLE AND OBSERVABLE PART OF HUMAN CHARACTERISTIC WHICH HAS A CONSEQUENCE UPON THE DESIGNED ARTIFACT. l I. E. HEIGHT OF A HUMAN BEING IS MEASURABLE.

FOUR CARDINAL CONSTRAINTS OF ANTHROPOMETRICS l CLEARANCE: IS THE ADEQUATE ROOM FOR A CERTAIN PART OF THE BODY TO ACCESS AND CIRCULATE WITHIN THIS SPACE. l THE ROOM THAT WE NEED FOR LEGROOM, HANDROOM, HEADROOM l ONE-WAY CONSTRAINT. 5% SATISFY 95% MALE IGNORED WE DONT TAKE INTO CONSIDERATION

l REACH: IS THE ABILITY TO GRASP AND OPERATE THE CONTROLS EFFICIENTLY. l ONE-WAY CONSTRAINT. 5% IS IGNORED VERY SMALL ONES SATISFY 95% IS SATISFIED

l POSTURE: IS THE POSITION OF THE HUMAN BODY WITH RESPECT TO THE WORK SURFACE. l TWO-WAY CONSTRAINT. IGNORE 5% 5%ILE FEMALE SATISFY 90% IGNORE 5% 95%ILE MALE

STRENGTH: l a) USER: AMOUNT OF FORCE TO BE APPLIED TO OPERATE CONTROL. l b) ARTIFACT: AMOUNT OF RESISTING FORCE. 95 TH%ILE SATISFY 95 %