3
$\begingroup$

I'm in need of help finding a third-order or higher system in which I can derive a transfer function. We have a class project in which we need to find a real-life example of the system that equates to a 3rd order system or higher.

The problem that I have is that I do not know what a third-order system looks like in real life. I can find a lot of examples of 2nd order systems (acceleration, velocity, and displacement). But no 3rd order! Help!

Project guidelines:

Step 1: Find a system of interest to you, discuss why this system is of specific interest to you and why this is a good topic for the class project;

Step 2: Model the system in three forms: differential equations, transfer function, and state-space representation. Note if the system is nonlinear, please linearize it first;

Step 3: Find and plot system output under step input and another input of your choice. Discuss the physical implications;

Step 4: Study the system stability, discuss the physical meaning of instability in your case;

Step 5: Assume a negative unity feedback system, two possible controllers:

$\ C_1(s)=k_0 $

$\ C_2s= k_p + k_ds+k_i \frac 1s $

• Design the two controllers, so that the system is stable.

• With all your designed control parameter values, what are the feedback system’s output under step input and another input of your choice?

• What are the steady-state errors under the four cases (2 controllers, 2 inputs)?

Improve this question
$\endgroup$
1
  • $\begingroup$ Rest assured, when you try wrapping it with sufficiently prompt control, any system will go right through 3rd-order and straight to multiple poles omygodomygod. Is this a thought experiment, or are you expected to haul physical objects into class? $\endgroup$
    – TimWescott
    Nov 5, 2019 at 0:38

1 Answer 1

Reset to default
2
$\begingroup$

The Temperature Control Lab is a third order system with heater 1 as the system input (controller output) and temperature 2 as the process variable. There are model development and control development modules in MATLAB and Python.

TCLab

Model Development

  • Simulate Step Response
  • Convective Heat Transfer
  • Radiative Heat Transfer
  • Linearize Energy Balance
  • First Order Plus Dead Time (Graphical)
  • First Order Plus Dead Time (Regression)
  • Impulse Response (Analytic Solution)
  • State Space Simulation
  • Second Order Response
  • Higher (Third or Fifth) Order Response

Control Development

  • Controller Design
  • P-Only Control
  • PI Control
  • PID Control
  • PI Control Tuning
  • PID Control Tuning
  • PID with Feedforward
  • Heater Actuator
  • Temperature Sensor
  • Block Diagram
  • On/Off Control

Here is the schedule for the course I developed with TCLab as the hands-on portion of the class. The topics cover almost all of your required topics.

Improve this answer
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.