Experiment: Design of a Feedback Control system

Instructions:
- This is a design experiment.
- Keep a record of all measurements taken, designs and screenshots.

Learning outcomes
- Be able to build a control system using MATLAB Simulink.
- Be able to investigate the control of a process using a proportional (P) and proportional- integral (PI) controllers.

Objectives:

It is required to design and build a P and PI controllers to control a process.

Experimental work:

The following transfer function represents a model of a certain process (plant):

G(s) = K/(Ts + 1)²

Choose values for the plant parameters using your data of birth such as:

K= day of birth (17)
T= month of birth (01)

Part 1: First-order Plus Time Delay Approximation

Using MATLAB Simulink, simulate the process with a unit-step change input (open-loop). Approximate this process with a first-order plus time delay model (see appendix A) and simulate with a unit-step input as well compare both responses and find the steady-state error, %OS (percentage overshoot). Setting time and the rise time for both cases.

Part 2: the P Controller Design
Design a P controller for the process and simulate the closed-loop response to a step input. Investigate the effect of changing (increase and decrease) the controller gain on the controlled response in term of the steady-state error, %OS. Setting time and rise time.

Part 3: the PI controller Design
Design a PI controller for the process and simulate the closed-loop response to a step input. Compare the response with the previously designed P controller in terms of the steady-state error, %OS, setting time and rising time. Investigate the effect of changing the integral action time on the controlled response.

Part 4: the effect of disturbance
Include a step disturbance at the input of the process (figure.1). obtain the unit-step responses for using the P and PI controllers. Measure and compare the maximum output responses, setting time and steady-state error in both cases. Which controller can remove the effect of the disturbance in steady-state? Why?

Figure .1

Part 5: Extra work

Design a PID controller to control the process (using Ziegler-Nichols method or otherwise). Find the parameters of the controller and test your system against disturbance at the input of the process.

Report marking:

Include a separate section for each of the main parts above. Each section should include method used and explanation and comments, appropriate diagrams (SIMULINK diagrams and simulation results) and a discussion of the results.