Today many houshold appliances have fuzzy logic built into them to make their use easier.
You can find fuzzy logic in shower heads, rice cookers, vacuum cleaners, and just about
everywhere. So you can get an idea how these machines work, we'll look at this simplified
model of a fuzzy washing machine.
Like a real fuzzy washing machine would, our model first tests how dirty the laundry is.
Once it knows how dirty the laundry is, it can easily calculate how long it should wash
it. To calculate this it uses the graph below:
First it always takes a base of 10 minutes. It does this so that people are happy with its
work even if they put completly clean laundry in to wash. It then calculates to what
degree it is dirty. If it is 100% dirty it adds two minutes per piece of laundry.
Of course a real washing machine would just do these calculations in the end, but our model
does it for each individual piece so you can keep track of what is going on easier.
So if you now add a piece which is only 50% dirty, it will add 50% of 2 minutes; it
adds 1 minute instead of 2 minutes to the base of 10 minutes.
Our washer, however, doesn't only check for dirt but also for grease. Laundry which is
greasy has to be washed longer too. Since the laundry can be greasy and dirty at the
same time, we have to put them on the same graph. When we do this, we get a graph like
the one below:
On the graph to the right, you can see once more the base of ten minutes. The point 0,0 is where
the laundry is completely clean; nondirty and nongreasy. The point 0,1 is where the laundry
is nongreasy, but dirty. The point 1,0 is where it is greasy but not dirty and 1,1 is greasy
and dirty. The washing machine adds 2 minutes per piece for 100% dirty or 100% greasy
and 4 minutes for 100% dirty and greasy.
So now if you have a piece of laundry which
is 100% dirty and 50% greasy, you first go to the point 0,1 (100% dirty) and then go halfway
towards point 1,1. If the cube would contain more information, you could now see that the
washer has to wash it for 3 minutes more than the base of 10 minutes.
Add a piece of laundry to the washer! 












These are only two aspects a fuzzy washing machine might take into account when washing. A real
one would also check to see how much soap it needs, how much water to add, how fast and which direction it should
spin, etc. If we wanted to graph every calculation a fuzzy machine makes, we would need a pretty
complex hypercube. So we'll just limit ourselves to grease and dirt.
There has been a boom for fuzzy machines in the last two decades. This is not only
because they can do things which we humans had to do ourselves until now, but also
because they're much cheaper to build than normal binary machines. But the idea on
which fuzzy logic is based, A can equal notA, isn't as modern as the fuzzy machines we
use today.