INTROUCTION
Automatic guided
vehicle or mobile robots is an intelligent machine that has intelligence to
determine its motion starts according to the environment conditions. For an AGV
to operate it must sense its environment be able to plan its operations and then
act based on this plan.
The running environment could be varied such as
the path orientation, road flatness, obstacle position, road surface friction
etc. There are great many uncertainties of what condition will emerge during its
operation. Thus a new control method other than the conventional control method
is demanded to manage the response of the whole system.
In the last
years, fuzzy logic has been applied mobile robot and autonomous vehicle control
significantly. The best arguments supporting fuzzy control are the ability to
cope with imprecise information in heuristic rule based knowledge and sensor
measurements.
Fuzzy logic can help design robust individual behaviors units. Fuzzy logic controllers incorporate heuristic control knowledge. It is convenient choice when a precise linear model of the system to be controlled cannot be easily found. Another advantage of fuzzy logic control is to use fuzzy logic for representing uncertainties, such as vagueness or imprecision which cannot be solved by probability theory. Also fuzzy logic offers greater flexibility to user, among which we can choose the one that best, fits the type of combination to be performed.
WHAT IS FUZZY
LOGIC?
Fuzzy logic is another class of AI, but its history and applications are more recent than those of the expert systems (ES). According to George Boole, human thinking and decisions are based on "Yes / No" reasoning or "1 / 0 " logic. According to Boolean logic developed and expert system principles were formatted based on Boolean logic. It has been argued that human thinking does not always follow crisp "Yes / No " logic, but is often vague, quantitative, uncertain, imprecise or fuzzy in nature.
For example in terms of "
Yes / No " logic, a thinking rule may be
" If it is not raining AND outside
temperature is less than 80 F ,THEN take a sight seeing trip for more than 100
miles"
In actual thinking it
might be
"IF weather is good AND outside temperature is mild THEN take a
long sight seeing trip".
Based on the nature of human thinking, Lotfi
Zadeh, a computer scientist at the university of California, Berkeley,
originated "The Fuzzy Logic" or "Fuzzy Set Theory" in 1965. In the beginning, he
was highly criticized by professional community, but gradually this emerged as
an entirely new discipline of AI. The general methodology of reasoning in
fuzzy logic and expert
system by "IF.. THEN…" statements or rules are the same, therefore it is often
called "Fuzzy Expert System "
A fuzzy logic can help to supplement an ES and it is sometime hybrid with the latter to solve complex problems. Fuzzy logic has been successfully applied in process control, modeling, estimation, identification diagnostics, military science, stock market prediction etc.