Diagnosis and FTC by Prof. Blanke [pdf] - NTNU

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Properties of possible architectures
A behaviour is the relation between variables
(input and output) of a function block:
c 1: g1( u, y)
= 0
3
example 1: y( t) − 2 u( t) u( t)
= 0
⎧dx()
t
⎪ =− 2 xt ( ) + 4 ut ( ); x(0) = xo
example 2: ⎨ dt
⎩
⎪ yt () = xt () −0.01()
ut
The
service offered
by a function block is to
provide a behaviour
between input and output.
S : g( u , y ) = 0
1 1 1 1
Properties of possible architectures
The behaviour of a system with an
architecture A is SA
With the two examples:
( upper )
S = S ∩S ∩S
A
1 2 3
All components must provide the service
to give the required service from u to y
( )
1 3
( lower ) ( ft )
( d )
SA= S1 ∩ S2 ∪S2 ∩S3
We obtain fault-tolerant behaviour if
( d )
S3
is fail-operational (can work despite any
( ft )
single fault) and S1
is fault-tolerant: we obtain
*
g(u,y) 1 1 ≈ g(u1,y 1)
but perhabs degraded
(lower performance)
Mogens Blanke – Spring 2006
Mogens Blanke – Spring 2006
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