Showing posts with label Ergonomics. Show all posts
Showing posts with label Ergonomics. Show all posts

Wednesday, August 26, 2009

Ergonomics in NID Gandhinagar by Dr. Prabir Mukhopadhyay

We had two weeks of Ergonomics course by Dr. Prabir Mukhopadhyay. It’s the most basic and compulsory course that any designer should undergo. For those who have no clue on what is Ergonomics is all about, According to The International Ergonomics association, Ergonomics (or human factors) is defined as the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance.

In UK / India its called as Ergonomics and in the US its called as Human Factors. It’s a simple naming problem. Basically they both are one and the same.

According to the discussion in class, Ergonomics is an interplay between Man, Machine and the Environment. Thus its an system level concept.

Ergonomics is divided into two categories:
• Physical Ergonomics
• Cognitive Ergonomics

Physical Ergonomics:
Under physical ergonomics we are concerned about the machine fitting into the human hand / leg / body physically. Thus measurements come into play. We need to know the extremes of human anatomical dimensions to decide each and every dimension for any desired product. No worry. People have already done enough work in this. Most of the data available are from the US thus we followed an Indian Authored book which has a collection of Indian anatomical values. These data are called Anthropometric Data. The best example will be like.. If you want to design a remote for television, it should be holdable by a huge variety of population. so one should know the minimum and the maximum inner diameter of a closed palm to decide on the dimension of that remote. Thus they have collected data from a wide population and have tabulated very neatly in the form of percentile. For making the measuring and considering procedure simple they have considered something called as “landmarks” in our body. It is nothing but any elevation or depression in our body.

For the first two days we played around with this data. We had huge confusions in what to select and what to avoid. Actually after having the data, things become more complicated. If you fix a display height considering a shorter person, a taller person may have to bend down badly to operate it. Thus decided upon a single value was a very tough exercise.

While deciding on the dimension we have to consider one thing for sure. Its called the “Take Of Point” (TOP). Its like… If you are deciding the height of a door, you have to consider the taller person’s height because shorter person can obviously pass through it. So “Clearance” becomes the concern here. If you are deciding the height of placement of the electric switch, you have to consider the shorter person’s height because taller person can obviously reach it. So “Access” becomes the concern here.

Thus keeping Clearance and Access in mind we have to decide the TOP and then worry on how to make life comfortable for the other people. The exercise was really good. We all were imagining a man standing and doing something. Sometimes with a tape measuring and fighting for a measurement among the group.

Then each group (3 members) were given with a project of redesigning any product which will have a display control ergonomically. We selected Treadmill as our product. As the user runs / walks in a Treadmill the amount of Antroprometric calculations to be made for it is too high and a lot of relaxation (dynamicity) has to be provided as the entire body is dynamic.

Before designing any product we have to consider the
• User’s profile
o Age
o Lot many parameters to consider according to the product
• Type of Task
o Precision (Elbow height is best suited. Eg. Hair cut)
o Force (Trochanter (Hip) height is best suited. Eg. Cutting Wood)
• Duration
o Less than a min
o More than a min
o More than 20 mins
• Work Wear

Then he spoke about the “Product Schematics”. Its like some products speak on its own. (Eg. Domestc knife handle having 4 curves on one side directs the user to hold that knife in that direction)

There are different zones in Physical Ergonomics:
• Primary (Space occupied when you stand straight and close your hands)
• Secondary (Space occupied when you stand straight and stretch your hands)
• Tertiary (Space occupied when you stand and bend in any direction)


There are two types of seating arrangements:
• Socio Fugal (No eye to eye contact. Eg. Public Places like railways staion)
• Socio Petal (Direct eye to eye contact. Eg. Restuarants)

Cognitive Ergonomics:
• Human Characteristics
o Will Forget
o Cant learn a lot to operate the product
• Mental Model
o Will expect a feedback (Eg. “Your files have been deleted” in Windows OS)
o Will expect a Reconfirmation (Eg. “Are you sure you want to delete?” in Windows OS)
o Always Curious

Then he spoke about the various stages of “Information Processing” in humans when handling any product.
1. Sensation
2. Perception
3. Cognition
4. Decision Making
5. Action Function
In this above said stages, only in stage 1,2,4 and 5 Ergonomics can be applied to improvise. Nothing can be done in Stage 3 - Cognition.

Design Ergonomics:
1. Scenario Building
2. Target user
3. User Study
4. Task Analysis
5. Concept generation
6. Prototype
7. Test
8. Final Product

Then while improvising our product we were supposed to do something called “Hierarchical Task Analysis” (HTA). Its like… mentioning every single action by the user with the product in sequence. Then all possible combinations with the logical and functional flow. A flowchart would give a more clear picture.

Then we have to do “Drury's Matrix”. This is like we have to put all the Hierarchical Task Analysis (HTA) in one column and then fill the other columns which include (Knowledge Required, Feedback Present ? (in what form), Potential Problems, Design Directions). The main advantage of doing this is that you know what kind of knowledge is required by the user to operate / do each and every task separately. Same way whether the feedback will be there or not. If no, then why not? This kind of questions will surely arise. Basically its to analyze the entire system step by step. The potential problems in each stage. In case of a mobile phone, while speaking, “Call End” button being pressed without user’s knowledge could be a potential problem. Then what kind of Design Direction can you come up with to solve this particular issue. Thus when you list the problems separately, there is no change of missing any problems while designing your product.

While designing the layout for any control display we can to consider the following in sequence:
1. Sequence of operation
2. Frequency of operation
3. Importance

A Quadrant Test should be done to decide which button can be placed where. Quadrant Test means, the interface / control panel will be divided into 4 quadrants and the user will be asked like… “where do you like to have the “call” button”… this input is not directly taken.. but this will be given more importance as this involves the mental model of the user.

Mental model” is nothing but what the user already knows. (Eg. All mobiles have some what similar keypad. Because users mental model is built that way. New mobile interface cant force the users to learn everything again. So going by the mental model is very important)

Stereotype” is the mindset which people carry / learn from their environment. (Eg. Switching on the power switch - down pressed in India, etc.. )

When going for Direct User Observations, we have to observe:
• Posture
• Repetitive movements
• Time taken for completion of a set task

More than all the above said theoretical knowledge, it all comes down to logic in the end. We can do anything but with a universally acceptable logic (with reference if possible). This makes the job very difficult. If you are asked to design a remote, you will say let the power on/off button be on the right top with red colour and 1 cm dia. But you should be able to answer why on the right top quadrant, why red colour, why 1 cm dia? Knowing a lot of Jargons might help a bit to communicate with the same field experts or convince the client.

Finally according to me, Ergonomics (Human Factors) is all about reasoning the logic behind every single parameter considered in a product development cycle.

If free do read this post by Siddharth Mankad...


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