Specifications

Hard-Disk Read/Write Head Controller
10-21
num = Ki;
den = [J C K];
H = tf(num,den)
MATLAB responds with
Transfer function:
0.05
-----------------------
0.01 s^2 + 0.004 s + 10
Thetaskhereistodesignadigital controllerthatprovidesaccuratepositioning
of the read/write head. The design is performed in the digital domain. First,
discretize the continuous plant. Because our plant will be equipped with a
digital-to-analog converter (with a zero-order hold) connected to its input, use
c2d with the 'zoh' discretization method. Type
Ts = 0.005; % sampling period = 0.005 second
Hd = c2d(H,Ts,'zoh')
Transfer function:
6.233e-05 z + 6.229e-05
-----------------------
z^2 - 1.973 z + 0.998
Sampling time: 0.005
You can compare the Bode plots of the continuous and discretized models with