What Is Fuzzy Logic?

trimf
Purpose
Syntax
Description
Triangular-shaped built-in membership function
y = trimf(x,params)
y = trimf(x,[a b c])
The triangular curve is a function of a vector, x, and depends on three
scalar parameters a, b, andc, asgivenby
( ) =
f x; a, b,
c
⎧ 0,
⎪
⎪
x−
a
,
⎪b−
a
⎨
⎪ c−
x
,
⎪ c−
b
⎪
⎩ 0,
x ≤ a ⎫
⎪
a ≤ x ≤ b⎪
⎪
⎬
b≤
x ≤ c⎪
⎪
c ≤ x
⎪
⎭
or, more compactly, by
f ( x a c x
x; a, b, c ) = ⎛ ⎛ − − ⎞
max⎜min ⎜ , ⎟,
⎝ ⎝ b−
a c−
b⎠
o ⎞
⎟
⎠
The parameters a and c locate the “feet” of the triangle and the
parameter b locates the peak.
Examples
x=0:0.1:10;
y=trimf(x,[3 6 8]);
plot(x,y)
xlabel('trimf, P=[3 6 8]')
4-90