PID controllers are popularly adopted in a wide range of industrial processes. The objective of this design practical is to study the way this PID controller changes system dynamics. Specifically you are investigating the following control system modeled by the block diagram shown below:

Where G is the gain of the system, a and b are the coefficients of the denominator polynomial. For this assignment use G=8, a=4 and b=25.

Three controller types will be studied in this assignment in the following sequence:
1.  PD controller

2.  PI controller

3.  PID controller

First determine the performance of your uncompensated system, which will form the benchmark for how much the system performance has been improved by compensation. Then carry out a comparison study of the three controller type (PD, PI and PID) and obtain typical results using these three controllers when the input is a unit-step. Restrict the values of Kp, Ki and Kd to be less than 10. In practice, this would represent the physical limits of the system components.