Page 74 - basic control system
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STEADY STATE ERROR, e ss
❑ This E (s) is the error in Laplace domain and is expression
in ‘s’
❑ In time domain, corresponding error will be e(t); remain
the steady state of the system as t → ∞ so:
, = lim ( )
→ ∞
❑ In Laplace domain, steady state error can be derived
as:
( )
=
1 + ( )
Notes
● For negative feedback systems, use positive sign in
denominator
● For positive feedback system, use negative sign in
denominator
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