Sticky Notes

This blog is officially closed. Do check out the new blog at http://www.utmrobocon.com

Friday, July 1, 2011

Phototransistor Line Finder with Fuzzy Logic Part II

In this discussion, I will write about the role of fuzzy logic in the line finder.

This a bit of introduction to fuzzy logic. It was first proposed by Zadeh; and Mamdani used it as a controller. Where the term Fuzzy Logic Controller came out.

Fuzzy logic is widely used in the field of soft computing and artificial intelligence. Basically there is two type, the Mamdani type and TS type. Let's not get into this.

Fuzzy logic can be used in place of digital logic. Well, we can call it analog logic. Imagine an AND gate using digital logic.
0 X 0 = 0
0 X 1 = 0
1 X 0 = 0
1 X 1 = 1

In analog logic, the example will be:
0.10 X 0.05 = 0.05
0.04 X 0.93 = 0.04
0.84 X 0.20 = 0.20
0.83 X 0.98 = 0.83
(Notice the result was based on MINIMUM function, we can use product function if we like)

Back to the line finder. What is the point of using analog logic, when digital logic could be used. It is used to create analog value from the reading.

So, example (analog range 0(left) to 100(right)):
Instead of 000001, we have 99;
Instead of 001100, we have 48;
Instead of 010000, we have 28;
Instead of 100000, we have 5;
et cetera.

Then why analog value instead of digital value?
Well, firstly, it is the resolution. Digital logic gives only limited resolution but in analog logic, the resolution is much higher. Secondly, using analog logic, better control algorithm could be devised. But in UTM ROBOCON, the control is still in the early stage and the current controller is only sufficient if the robots are straight in the first place.

This concludes the second part.

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