"Fussing ove Fuzzy Logic" by Janani Gopalakrishnan

If you go shopping for appliances these days, you just cannot miss the word “fuzzy logic” and related terms like “active cooling”, “auto cut off”, “temperature control” or “sixth sense” in the promotional talk that the salespeople give you. So, just what is this fuzzy logic? If you ask the salespeople there, very rarely will you get a precise and scientific explanation of the term; they will only be interested in explaining the related product features to you.

Here, in this article, we explore the actual concept of fuzzy logic and how it is being used in appliances, so we can be better informed about the appliances we use and also more familiar and comfortable with them, knowing there is no magician inside, just a simple electronic board!

Fuzzy Logic to Make Life Easier
Years ago, when you operated a washing machine, you had to give it precise settings or inputs. You had to put in the clothes and clearly mention the water level, wash options etc. But in today’s fully automatic machines, you just have to put the clothes inside the washing machine and stand back to watch it determine the amount of clothes, automatically setting the amount of water required, detergent needed, wash cycle, and such details.

Some very advanced washing machines even have optical sensors to measure the murkiness or clarity of water, thereby determining when the water should be changed. Others have the ability to continuously monitor the stains in the clothes using optical sensors. Depending on the intensity of the stain, the machine changes the wash strategy, varying the agitation rate, water temperature etc. till the stain is completely removed. This ability of the washing machine to simulate the commonsense of human beings is a result of the usage of fuzzy logic.

To Match Commonsense
Fuzzy logic is not a new concept. Way back in 1965, Professor Lofti A. Zadeh of the University of California, at Berkeley was amazed by how people were able to make precise decisions even when faced with vague situations, while electronic devices could not. Electronic devices then needed very precise inputs, clearly classifiable as Yes/ No, True/ False values. Humans could see an environment as “quite cool” or “quite hot” but electronic devices could not recognise such indistinct values.

He thought that if feedback controllers could be programmed to accept noisy, imprecise input, they would be much more effective, quite akin to human thought. The result of his research was fuzzy logic, a mathematical model to represent human logic. It tries to imitate how a human would make decisions.

It provides a simple way to arrive at a definite conclusion based on vague, imprecise or even missing input information, which is how things are in reality. In truth, things are not always Yes or No. Real life situations are often partly true or partly false. Fuzzy logic systems understand that there are varying degrees of everything rather than just extremities. It helps deal with imperfect environments of highly variable, volatile or unpredictable conditions.

For example, in a washing machine there can’t always be full load or half load. The amount of clothes you load into a machine varies every day. Fuzzy logic machines understand this and vary the water levels etc. based on the load of clothes.

This problem-solving methodology could lend itself to small, embedded microcomputers (like those in-built in home appliances) to large, networked scientific workstations.

Fuzzy Logic in Modern Appliances
Though fuzzy logic was born in America, it was the Japanese who were quick to embrace the technology, aggressively building real products around it. Fuzzy logic today finds application in a wide range of appliances, like refrigerators, vacuum cleaners, washing machines, rice cookers, microwave ovens, air-conditioners etc.

In modern domestic appliances, fuzzy logic manifests as feedback systems that use sensors to detect a variable and adjust a corresponding machine function; for example, some microwave ovens automatically adjust the cooking time depending on the quantity of foodstuff being cooked. Even more advanced ovens vary the cooking temperature and time based on the varying humidity level of the food!

Another example is today’s state-of-the art fridges with the feature called ‘active cooling’ or some similar name depending on the brand. These fridges direct cooler air to warmer areas of the fridge, thereby maintaining a constant temperature. In some fridges, when you keep the fridge open for some time or when you load it with a lot of things and the temperature becomes warm, then the fridge automatically increases the cooling in order to revert to the former coldness. These are all examples of feedback systems using fuzzy logic i.e. as a result of detecting a change in some variable (temperature in the case of a fridge) some feedback/ action is triggered (for example, faster cooling).

How Does Fuzzy Logic Work – Getting a Little Technical
You can think of all modern appliances as having really, really tiny computers inside them, sensing and processing user input and controlling the behaviour of the appliance. Fuzzy logic devices work by means of a series of If-Then rules which the devices understand with the help of adaptive systems called neural networks. Instead of just an on or off situation, these rules tell the device how to handle a variety of situations.

Consider the case of an air conditioner that has to always maintain an optimum temperature by controlling the speed of the fans inside. In simplified terms, its rule set may be something like the following:
If temperature is very cold then stop fan
If temperature is cold then slow down the fan
If temperature is normal then maintain the fan level
If temperature is hot then speed up the fan

Pairs of values representing the rules will be provided to guide the appliance. In the example of the air conditioner, the pairs of values may be linking temperatures and motor speeds. It’s almost like giving instructions to a human being!

Fuzzy Logic – The Future is not so Fuzzy
Fuzzy logic is here to stay, and it is going to make lives so much easier for us. Very soon, we will have ovens automatically baking potatoes, without us having to provide any settings, not even the weight. How nice it would be to have a grinder that automatically stops when your idly batter is done, without you having to check. Or a TV that increases the volume spontaneously when the environment gets noisy. Maybe, a light that grows brighter as the evening gradually becomes darker. Fuzzy logic is soon going to take over all our devices. And trust me, now that you know all about the technology behind it, you will be greeting it with so much more confidence!
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