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.