ECE 486 Control Systems Lab (Fall 2017)

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Day 1 Day 2 Day 3 Day 4 Short labs, weekly
Day 5 Day 6 Day 8   Long labs, biweekly
Day 7 Day 9 Day 10 Day 11 Final project, weekly

Week 4 – Final Project: Reaction Wheel Pendulum

Day 111 of ECE 486 Lab, Week 4 of Final Project.

What Chapters Should We Complete during Fourth Week?

Chapters 6 and 7 are extra credit chapters. They are not required.

Chapter 6 (Extra Credit)

On top of the Up Controller we designed in Chapter 4, we relinearize Equation of Motion of RWP around \(0\) rather than \(\pi\), i.e., the first state \(\delta \theta_p = \theta_p - \pi\) changes to \(\delta \theta_p = \theta_p - 0\).

This change will result in a change in \(A\) matrix, which was used to compute controller gain \(K = {\texttt{place(A, B, poles)}}\).

Chapter 7 (Extra Credit)

If the hint in the Final Project is the way we go for, the important thing to notice in the sequence of figures of illustrated swing-up control is, when pendulum speed is positive \(\dot{\theta}_p > 0\), the control is negative \(u < 0\); when pendulum speed is negative \(\dot{\theta}_p < 0\), the control is positive \(u > 0\). In other words, the sign of the control effort \(u\) is always opposite to the sign of swinging speed of the pendulum \(\dot{\theta}_p\).

The above talks about the sign of the control \(u\), how about its magnitude? One way to design its magnitude is to peg \(|u|\) to how close the pendulum is to \(\pi\) position. If the pendulum is close to the top, use a small control; otherwise, use a large control. For example, if the pendulum is at the down position, we probably want to max out the control to get it swing up quickly.

A Few Suggestions

  • A recap of suggested schedule of Final Project,

    Week 1 (Oct 30) Complete Chapter 1 - 2
    Week 2 (Nov 30) Complete Chapter 3 - 4 (first half)
    Week 3 (Dec 7) Complete Chapter 4 (second half) - 5
    Week 4 (Dec 14) Complete Chapter 6 - 7 or catch-up
  • Important: A TA is not supposed to give “hand-holding” guidance during the period of students’ Final Project. There is no constraint on how fast or how much work each group needs to complete each week. Students can go as fast as they wish. But it is always strongly recommended that students document their work each week and write up pieces of Final Project Report on the go. Start typesetting Final Project Report one day before it is due is the very first thing each group should avoid.
  • There is no official template for the report so students are free to design their own. However all questions in the guidelines should be responded to with clear answers; these are the minimum requirements of the report.
  • Since we are going to use Simulink™ Windows Target®, it is not a good idea to run your files from a network path. For example, you may need to create a folder named after your NetID in local C:\ drive and save your Matlab WinTarget files there. Move the folder to your thumb drive once you are finished.

    Always keep C:\ drive clean and organized.

  • To protect the RWP module, make sure power cords and data cable are firmly plugged in before turning on the power strip.
  • As for exporting data, a scope block is recommended. To save data, click the gear icon (options) then go to Logging tab and name your data variable. Use Save format Array.
  • Each time you are done with the RWP, you are supposed to restore the RWP back to the cabinet; you can work on the final project any time you want but you are not supposed to take it outside the lab.
  • Always clean up before exiting. Specifically,
    • Clean up bench table, restore pot, motor lock etc, reinstall screws;
    • Sort out wires color by color, type by type and put them back to racks;
    • Turn off oscilloscope, meters etc;
    • Restore chairs.



Please start/continue writing your Final Project Report and it is due by 5pm, Dec 18 in the dropbox in lab 3077 ECEB.

Due Date

Final Project Report is due 5pm on Dec 18. Final Project Report must be typeset.


You are always very welcome to stop by office hours on Mondays. Emailing questions is another way. You can always include [ECE486]blah in the title of your question emails.

Spot any typos? Email me at once. You will earn up to +5 points for each typo/technical error reported.


This is the last lab this semester.

Author: Yün Han

Last updated: 2017-12-16 Sat 07:09