Assignment Tasks

Video Laser Disc Recorder

$($solve it as mat lab codes$)$

In order to record on a video laser laser disc, a $0\mathrm{.}5m$ aser spot must be focused on the recording medium to surn pits that represent the program material. The small laser spot requires that the focusing lens must be positioned to an accuracy of $+-0\mathrm{.}1m.$ A model of the feedback control system for the focusing lens is shown in Figure $1.$

Page $1$ of $11$

The detector detects the distance between the focusing lens and the video disc by measuring the degree of focus as shown in figure $2.$ When the beam is in focus, the voltage output from both sides of the photodiode are equal.

Figure $1$: Model Block Diagram of the Focusing Lens

Page $2$ of $11$

Requirements:

For the given set of parameters $K_1=10,K_2={10}^7$;$K_3=70,$ and using MATLAB, evaluate the Video Laser Disc Recorder $($VLDR$),$ in terms of its transient time response and its frequency response. Determine also the range of the overall gain to maintain the stability of the system.

To improve the time response of the Videc Laser Disc Recorder, design a compensator to be cascaded with the recorder and improve settling time by two folds, percent overshoot by $\frac{1}{3}$ as well as steady$-$state error of $0\mathrm{.}2$ or better.

Analyze the system performance of the uncompensated and compensated systems and comment on the percentage improvement. Provide the simulation results to prove the improvement.

The results will be verified by viva voce

$($matlab$)$