HW 2 Identification Hard- Disk Servo System
A Hard-disk servo system has the following input-output model:
ż = −5z + u + d
where the output z and the input u are measured signals . The unknown disturbance d(t) is
given by
d = a1 cos(ω1 t + ϕ1 )
The parameters a1 and ϕ1 are known, but ω1 is known.
(1) Obtain the SPM.
(2) Derive an adaptation law for estimating d(t).
(3) Now assume that ω1 = 2πf1 , f1 = 1.5, a1 = 3, ϕ1 = 30o .
Choose
(a) u(t) = 10 cos 2t,
(b) u = 10.
Simulate and plot parameter estimation error. Discuss what you observe for the two kinds of
inputs.
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