Specifications

Hard-Disk Read/Write Head Controller
10-25
D = zpk(0.85,0,1,Ts)
oloop = Hd * D
Now see how this compensator modifies the open-loop frequency response.
bode(Hd,'--',oloop,'-')
The plant response is the dashed line and the open-loop response with the
compensator is the solid line.
The plot above shows that the compensator has shifted up the phase plot
(added lead) in the frequency range rad/sec.
Now try the root locus again with the plant and compensator as open loop.
rlocus(oloop)
zgrid
ω
10
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