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A Graphical User Interface (Gui) For A Unified Approach For Continuous Time Compensator Design

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2008 Annual Conference & Exposition


Pittsburgh, Pennsylvania

Publication Date

June 22, 2008

Start Date

June 22, 2008

End Date

June 25, 2008



Conference Session

Instrumentation and Laboratory Systems

Tagged Division

Computers in Education

Page Count


Page Numbers

13.45.1 - 13.45.14



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Paper Authors


Minh Cao Wichita State University

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Minh Cao completed his Bachelor’s of Science degree at Wichita State University in 2004. He completed his Master’s of Science degree at Wichita State University in 2007. He is currently working as a Senior Electrical Engineer at Hawker Beechcraft Corporation.

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John Watkins Wichita State University

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John M. Watkins is an Associate Professor in the Department of Electrical and Computer Engineering at Wichita State University. He received his B.S. degree in electrical engineering from the University of Nebraska-Lincoln in 1989 and his M.S. and Ph.D. degrees in electrical engineering from The Ohio State University in 1991 and 1995, respectively. His research interests include feedback control and time-delay systems.

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Richard O'Brien U.S. Naval Academy

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Richard T. O’Brien, Jr. (M'97) was born in Jersey City, NJ in August 1969. He received his Bachelor of Science in Engineering with Honors in 1991 from Brown University, Providence, RI, Masters of Science in Engineering and Doctor of Philosophy in Electrical and Computer Engineering from The Johns Hopkins University, Baltimore, MD, in 1994 and 1998, respectively. Since 1997, he has been on the faculty of Systems Engineering Department of The United States Naval Academy where he has been an Associate Professor since 2002. Dr. O'Brien's current interests include H-infinity control and estimation.

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NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract

A Graphical User Interface (GUI) for a Unified Approach for Continuous-Time Compensator Design


As an alternative to the numerous distinct controller design algorithms in classical control textbooks, a simple unified design approach, which is independent of the form of the linear system information, was developed in previous work for all standard classical compensators. This approach is based on a simple root locus design procedure for a proportional-derivative (PD) compensator. From this procedure, design procedures for unified notation lead, proportional-integral (PI), proportional-integral–derivative (PID), and PI-lead compensator were developed. With this proposed approach, students can concentrate on the larger control system design issues, such as compensator selection and closed-loop performance, rather than the intricacies of a particular design procedure.

Once students learn the unified design process discussed above, it is important that they get an opportunity to apply it to design and laboratory projects. Most real life examples require design iterations. The Graphical User Interface (GUI) developed in this paper not only makes this feasible, but also makes this an excellent learning opportunity. The authors have implemented the unified compensator design procedure as a GUI in MATLAB. The GUI presents the user with both root locus and Bode information. Either domain can be used for design. The effect of the design on both domains can be seen instantaneously. The GUI also provides the user with the closed-loop step and Bode response as well. Design specifications in the time and frequency domain are easily verified.


In controls education today, there seems to be gap between the theory taught in the typical undergraduate classroom and the skills required for practical application of control systems. One obvious reason for this is the lack of undergraduate control system laboratories. The control systems community has recognized this need.1,2 In many departments around the world, undergraduate control system laboratories are being developed.3,4 A less obvious reason for this gap is the “cookbook” approach to compensator design found in typical classical control textbooks.5,6,7 For example, a quick comparison reveals significant differences in the procedures for root locus lead design and root locus Proportional-Integral (PI) design. Even more importantly, there are significant differences in the procedures for lead compensator design using root locus techniques and Bode techniques. Furthermore, for even simple systems, these design procedures may yield poor results.8 Therefore, students end up concentrating on the different “recipes” that may or may not yield satisfactory results, and, consequently, tend to miss the “big picture”.

In previous work, design methods were developed that permit students to apply a simple, unified design approach for six standard compensators (Proportional-Derivative (PD), lead, Proportional-Integral (PI), lag, Proportional-Integral-Derivative (PID), and PI-lead independent of the form of the system information.9,10 In root locus design, the computational procedures are

Cao, M., & Watkins, J., & O'Brien, R. (2008, June), A Graphical User Interface (Gui) For A Unified Approach For Continuous Time Compensator Design Paper presented at 2008 Annual Conference & Exposition, Pittsburgh, Pennsylvania. 10.18260/1-2--4128

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