- Email: [email protected]
Teaching Entry Level Control Course via a Pilot Design Proect: A Motivation-By-Chalange Approch
Copyright
e IFAC Advances in Control Education.
Tokyo. Japan. 1994
TEACHING ENTRY LEVEL CONTROL COURSE VIA A PILOT DESIGN PROJECT: A MOTIVATION-BY-CHALLENGE APPROACH J. Jim Zhu Lo"i.iana State Usiwe?'.it,. Department of Electrical as4 Comp"ter En,i.eerin" Baton Ro",e, LA 70803, U. S. A .• E",.il: zh"O.... ra.r.ip.I... ec"
Ab.t.nct. An UDCODYCIltional, motivation·by·challent;e approach i. reported Cor teaching entry level control CO~. This approach recognizes the difference between pauille learnin, and active learn in,. therefore empbuizes on motivating the entry level students with a pilot design project that is woven into Aec\_ from beginning through end.
Key Word.. Ed~; Control Systems; Control Theory; Teaching; Design Project; Motivation· by· Challenge ApproAch
1. INTRODUCTION
will face constant challenges of ever demanding engineering applications, fast evolving technology, and increasingly competitive workplace as well as marketplace. Thus, it is crucial to, using Masten's words [Masten, 1991], "instill attributes that we know are essential to success without sacrificing technical knowledge that is basic to the selected engineering discipline ... "
In this paper the experimentation with an unconventional approach is reported for teaching entry level control courses: the motivation-bychallenge approach. Conventional teaching approach usually takes the sequential paradigm shown in Figure 1. While this approach is mostly effective for a systematic dissemination of the theory, it may not be the most effective approach for the students to acquire the knowledge. Indeed, the latter is particularly the case for entry level Uunior/senior undergraduate) students who are mathematically immature or even intimidated, who have never had any industrial or practical experience with an automatic control system, and who have not yet dedicate themselves to a lifetime career in control engineering.
The new approach reported in this paper constitutes an attempt to address these issues. This approach recognizes the difference between active learning and passive learnin!la motivated student learns a subject of interest much faster, understands the subject deeper, remembers longer, and more importantly, is willing and eager to explore further with or without the instructor's assistance. The key to active learning is motivation, and the approach taken here is motivation-by-challenge. This approach is implemented in teaching an entry level control course via a pilot design project that is woven into the lectures from beginning through end.
As reported in [Dorato and Feliachi, 1991], the lack of mathematical prerequisites in the undergraduate control curricula is particularly acute in the United States, comparing to the rest of the world. Consequently, the students in the U.S. are expected to learn from a control course not only the engineering aspects of controls, but also the necessary mathematical theory and skills. Thus, it is even more important to motivate the students in an entry-level control course and prepare them for the upcoming endeavor.
It is noted that many control textbook authors, such as [Kuo, 1991] and [Dorf, 1992], have realized the importance of using design problems to illustrate the concepts and methodology. Some authors, such as [Nise, 1992], have included one central-theme design problem throughout the text. The approach presented here goes one step further in that the pilot project is used in the first place to challenge and motivate the students.
Even more importantly, more then 80% of the undergraduate students will eventually go to industry, according to [Masten, 1991], where they 87
Application
Prerequisi te --t
Theory
--t
Laboratory
Examples
Math
Learning
-----+
1--1
(Optional)
Fig. 1. Conventional teaching paradigm Real-world proble~$ Challenge
Mathematics Theory
Laboratory ----4
Problem solution
Generalization
Learning
(Optional)
Fig. 2. Motivation-by-challenge teaching paradigm This new approach has been experimented by the author with marked success in teaching the first control course EE-4510 at senior level} in the Department of Electrical and Computer Engineering (ECE), Louisiana State University (LSU). Problems with this approach and suggestions for further improvement are also addressed in this paper.
studies of more advanced topics. The entire course can be divided into the following five stages led by a respective challenge. t.1. Cid/eage oJ- re"'-tDorld coatrol pr06lem.
A real-world control problem is identified at the beginning of the course and assigned as a design project. The problem should: (i) encompass modeling, simulation, analysis and control, (ii) be tractable by entry level theory, and (iii) be executable within the limited time. Beyond these necessary requirements, the key to success in selecting such a real-world problem is the realism in terms of problem statement; design specifications and their commercial/economical consequences; the non-ideal operating environment such as noises, disturbances, uncertainties, etc.; project deliverables such as report, simulation and (optional) hardware implementation, perhaps on a laboratory setup. Of course the realism has to be appreciable by the students.
2. MOTIVATION-BY-CHALLENGE The new, motivation-by-challenge teaching approach follows the paradigm shown in Figure 2. As can be seen, in this approach, solving a realworld problem is the driving force of the learning process, and the discrepancy between the problem solution and the problem requirement poses a challenge and a need for mathematics and theory, thereby forming a closedloop, iterative learning process. It is noted that, while the problem-driven learning loop is effective in motivating entry-level students, the post generalization procedure is necessary and important for acquiring general, abstract knowledge. In teaching EE-4510 at LSU by the author, the course is led by a pilot design project of an industrial control problem-a voice-coil DC motor drive system for a computer disk drive read-write head position control, which is assigned at an early stage and continued throughout the course. The project is used to pose challenges to the students at various stages of the course, thereby motivating the students for the upcoming mathematical treatment and theoretical study. The dissemination of the theoretical contents of the course has to be reorganized to accompany each stage of the design process, and to focus around the need of the pilot project, with provisions of generalization and further
For instance, as the disk drive control project is handed out to the students, the evolution of disk drive technology, from the st-inch, full-height, single-side, single-density (90 KB) floppy disk drive to today's credit-card size hard disk drive, and its impact on the advancement of personal computer technology are introduced. A 5{ -inch, half-height, double-side, double-density (360 KB) floppy disk drive and a notebook computer are presented to the students, where the latter is twice the size of the floppy disk drive, but fully equipped with a 3~ -inch double-side, high-density (1.44 MB) floppy disk drive, an 80 MB hard disk drive, in addition to the keyboard, built-in mouse, VGA LCD screen, battery and 486 CPU. While the students are amazed by the technological advancement taken place in the past decade,
1 Beginning Spring, 1994, the first control course is changed to EE-3530 taught at junior level. The new approach is being applied to teaching this course by the author at the time of writing.
88
the demand of this advancement on control engineering is explained. Increased disk density and access speed require higher control precision (reduced steady-state error) and fast transient performance, while reduced size and energy consumption call for optimally designed and implemented controllers, actuators and sensors. At this time the students are fully charged up and eager to meet the challenge.
tor-amplifier block-diagrams are the closest simulation to physical implementation using available electronic components. The reasons that transfer function blocks or procedural simulation (such as MATLAB® programs) are not favored for entry level students are: (i) transfer function blocks, as presently implemented in most block-diagram simulation software packages, such as MATLAB-SIMULINK®, VisSim®, do not allow simulation of natural (zero-input) response of the plant, (ii) transfer function blocks, and similarly procedural simulation programs, simplify mathematical expressions at the cost of obscuring physical intuition. For the purposes of stimulating the students, the author has had very positive experience with VisSim.
To facilitate the understanding of the problem and the project assignment, a radical change in the lecture contents has to be made, namely the typical dynamical behaviors and performance indexes such as the overshoot, settling-time, steady-state error, etc. need to be introduced before even mentioning about such topics as damping ratio, natural frequency, etc. But this can be easily achieved when the physical meanings and commercial/economical consequences of such performance indexes are explained with respect to the pilot project.
Both the idealized (linear time-invariant) model and a more accurate model (nonlinear, timevarying, with noise and disturbances) should be built to show the differences. This will serve the purpose to motivate the students for further study of advanced topics in control. The need for further analysis and compensation of the dynamical behavior of the plant should be revealed through simulation studies.
!.!. Claalleate 0/ mo"e1iat. The need for quantitatively modeling the system /process to be controlled, i.e. the plant, comes naturally as the necessary first step of the design process, differential equations, transfer functions, signal flow graph, state equations, etc. are readily acquired by the students. Modeling of nonlinearities, time-dependence and uncertainties of the plant, noises and disturbances in the operating environment should also be treated here at appropriate levels, such as linearization, slowly time-varying assumption, or simply mention but ignoring some aspects, such as sensor noise, and leaving them to later simulation studies of the their effects on system performance.
!.-I. Claalleate o/.a."m. While the modeling process is certainly a mathematical challenge to entry level students, the analysis is the grand challenge. One of the best way to motivate the students to commit themselves to and to endure such an undertake comes from the frustration and failure of the most intuitive and straightforward de!'igll method: design by trial-and-error without any theoretical insight and guidance. The intuitive concept that the system parameters (the coefficients of the differential equations) determine the system behaviors and state-feedback can be used to alter these parameters (of course with the unrealistic assumption that all the state variables are directly measurable) are readily accepted by the students, and a trial-and-error design is assigned to the students. As the students getting frustrated with the experimentation, theoretical development of analytical solutions, criteria for stability, controllability and observability are introduced. At this stage, a more advanced trial-and-error design based on the idea of eigenvalue (pole) assignment is assigned to further challenge the students for a systematic development of controller design techniques.
!.3. Claalleate 0/ nmal.tiOfl. The need for validating the mathematical model of the process, and the possibility of studying the behavior of the plant without having to physically build it leads to the introduction of computer simulation techniques. Theoretical development accompanying this stage is the various (canonical) realization techniques. Although many control simulation software packages are commercially available, it is believed one that implements the model using blockdiagrams of integrators, and linear/nonlinear amplifiers (not transfer function blocks) serves the purpose best. This is because: (i) blockdiagram simulations can be built directly from the various (canonical) realizations developed in the lectures, (ii) once the physical implementation of an integrator and an amplifier using an operational amplifier is explained, such integra-
!.5. CIa.ueate
0/ "enp.
Upon addressing the need for dynamical feedback control, such as integral feedback for improved steady-state accuracy, state observer for inaccessible state variable measurements, the 89
various control techniques for linear timeinvariant systems can be summarized as the aids for selecting the "optimal" locations of the eigenvalues of the overall closed-loop system. By now the students should be ready to accept at any price any design technique that will help them to get out the seemingly hopeless trail-and-error design practice. Many real world issues revealed in the design project, such as tradeoffs between transient performance and steady-state accuracy, transient performance and robustness, overall performance and control energy consumption, model accuracy and ease of analysis, serve as motivations for the students to undertake further studies of advanced control topics such as optimal, robust and nonlinear control.
the most time-consuming part of the project and also the most frustrating for me. I was eventually led into writing a computer program that would find a satisfactory K matrix for me. I wrote the program in MATLAB ... However, I had to learn much about MA TLAB in order to write the program. (This is part of the overall knowledge I gained from the project.) ... The fact that I was able to program the computer (and the program succeeded) to find the optimum K for the systems was very gratifying. (R.
A. Richard)
2) In completing this project, I feel a great sense of accomplishment and that my money has been well spent in pursuing a degree in electrical engineering. Now, I say on to EE~580 (a second control course on classical design techniques). (C. Fontenot)
3. SUMMARY AND CONCLUSIONS
9) I found this project (Project 11) to be a great learning experience .... My after thoughts on this project center around one question: can my design actually be built'l •..1 guess one day, after my retirement and (having) a lot more experience, I'll pull out these two project reports that I did in controls and actually attempt to build it. Before I took the controls class, I felt that controls might be the field I would like to specialize in. After these projects I feel more strongly. (D. BourgeoIs)
After some painstaking experimentation and with the enthusiastic support from the students, this new teaching approach has achieved marked success as indicated by: (i) drastically increased grades of many students during the course; (ii) enthusiastic comments from the students at the end of the project (cf. student quotations shown below); (Hi) self-initiated, unsupervised exploration by the students (cf. Quotation 1 shown below); and (iv) a great increase in the enrollment of subsequent technical elective courses in controls. Problems with this new teaching approach include: (i) excessive time spent by the students on the project; (ii) frustration due to repeated failure; (Hi) synchronization between the design process and the theoretical development. These problems are believed to be solvable by further improvement of the project assignment and the accompanying lectures, and a finetuned balance between student self-exploration and instructor assistance. For the latter, it is felt that the instructor needs to be vary sensitive to signs of frustration of the students, and to establish at an early stage complete confidence and trust among the students. Another improvement is to include an accompanying laboratory course, which is not presently available at LSU.
4. REFERENCES Masten, M.K. (1991). An industrial challenge to control system educators, Proceedings, IFA C Conference on Advances in Control Education, Boston, MA, U.S.A.
Dorato, P., and A. Feliachi (1991). Control systems curricula in the United States: results of two recent surveys, Proceedings, IFA C Conference on Advances in Control Education, Boston, MA, U.S.A.
Yurkovich, S. (1992). Advances in control education, IEEE Control Systems Magazine, Vo1.12, No.3, 18-21. Kuo, B.C. (1991). Automatic Control Systems, 6th Ed., Prentice-Hall, Englewood Cliffs, NJ. U.S.A. Dorf, R.C. (1992). Modern Control Systems, 6th Ed., Addison-Wesley, Reading, MA., U.S.A. Nise, N.s. (1992). Control Systems Engineering, Benjamin/Cummings, Redwood City, CA, U.S.A.
The author wishes to conclude this paper by sharing the following gratifying comments from the students: 1) A nother positive reflection I have is that the projects have raised my interest in the area of control systems, ... My interest was raised so much that I plan to take another control systems class in the future .... Finally, the one area of the project that captured my attention the most was finding a K matrix that allows the closed-loop system to perform up to the design requirements. The search for this optimum K matrix became
Ach01llleflgemeat. The author sincerely thanks Dr. J. L. Aravena, ECE Department, LSU, for his enthusiastic support and help in experimenting with the motivation-by-challenge teaching approach and in writing this paper. 90
e IFAC Advances in Control Education.
Tokyo. Japan. 1994
TEACHING ENTRY LEVEL CONTROL COURSE VIA A PILOT DESIGN PROJECT: A MOTIVATION-BY-CHALLENGE APPROACH J. Jim Zhu Lo"i.iana State Usiwe?'.it,. Department of Electrical as4 Comp"ter En,i.eerin" Baton Ro",e, LA 70803, U. S. A .• E",.il: zh"O.... ra.r.ip.I... ec"
Ab.t.nct. An UDCODYCIltional, motivation·by·challent;e approach i. reported Cor teaching entry level control CO~. This approach recognizes the difference between pauille learnin, and active learn in,. therefore empbuizes on motivating the entry level students with a pilot design project that is woven into Aec\_ from beginning through end.
Key Word.. Ed~; Control Systems; Control Theory; Teaching; Design Project; Motivation· by· Challenge ApproAch
1. INTRODUCTION
will face constant challenges of ever demanding engineering applications, fast evolving technology, and increasingly competitive workplace as well as marketplace. Thus, it is crucial to, using Masten's words [Masten, 1991], "instill attributes that we know are essential to success without sacrificing technical knowledge that is basic to the selected engineering discipline ... "
In this paper the experimentation with an unconventional approach is reported for teaching entry level control courses: the motivation-bychallenge approach. Conventional teaching approach usually takes the sequential paradigm shown in Figure 1. While this approach is mostly effective for a systematic dissemination of the theory, it may not be the most effective approach for the students to acquire the knowledge. Indeed, the latter is particularly the case for entry level Uunior/senior undergraduate) students who are mathematically immature or even intimidated, who have never had any industrial or practical experience with an automatic control system, and who have not yet dedicate themselves to a lifetime career in control engineering.
The new approach reported in this paper constitutes an attempt to address these issues. This approach recognizes the difference between active learning and passive learnin!la motivated student learns a subject of interest much faster, understands the subject deeper, remembers longer, and more importantly, is willing and eager to explore further with or without the instructor's assistance. The key to active learning is motivation, and the approach taken here is motivation-by-challenge. This approach is implemented in teaching an entry level control course via a pilot design project that is woven into the lectures from beginning through end.
As reported in [Dorato and Feliachi, 1991], the lack of mathematical prerequisites in the undergraduate control curricula is particularly acute in the United States, comparing to the rest of the world. Consequently, the students in the U.S. are expected to learn from a control course not only the engineering aspects of controls, but also the necessary mathematical theory and skills. Thus, it is even more important to motivate the students in an entry-level control course and prepare them for the upcoming endeavor.
It is noted that many control textbook authors, such as [Kuo, 1991] and [Dorf, 1992], have realized the importance of using design problems to illustrate the concepts and methodology. Some authors, such as [Nise, 1992], have included one central-theme design problem throughout the text. The approach presented here goes one step further in that the pilot project is used in the first place to challenge and motivate the students.
Even more importantly, more then 80% of the undergraduate students will eventually go to industry, according to [Masten, 1991], where they 87
Application
Prerequisi te --t
Theory
--t
Laboratory
Examples
Math
Learning
-----+
1--1
(Optional)
Fig. 1. Conventional teaching paradigm Real-world proble~$ Challenge
Mathematics Theory
Laboratory ----4
Problem solution
Generalization
Learning
(Optional)
Fig. 2. Motivation-by-challenge teaching paradigm This new approach has been experimented by the author with marked success in teaching the first control course EE-4510 at senior level} in the Department of Electrical and Computer Engineering (ECE), Louisiana State University (LSU). Problems with this approach and suggestions for further improvement are also addressed in this paper.
studies of more advanced topics. The entire course can be divided into the following five stages led by a respective challenge. t.1. Cid/eage oJ- re"'-tDorld coatrol pr06lem.
A real-world control problem is identified at the beginning of the course and assigned as a design project. The problem should: (i) encompass modeling, simulation, analysis and control, (ii) be tractable by entry level theory, and (iii) be executable within the limited time. Beyond these necessary requirements, the key to success in selecting such a real-world problem is the realism in terms of problem statement; design specifications and their commercial/economical consequences; the non-ideal operating environment such as noises, disturbances, uncertainties, etc.; project deliverables such as report, simulation and (optional) hardware implementation, perhaps on a laboratory setup. Of course the realism has to be appreciable by the students.
2. MOTIVATION-BY-CHALLENGE The new, motivation-by-challenge teaching approach follows the paradigm shown in Figure 2. As can be seen, in this approach, solving a realworld problem is the driving force of the learning process, and the discrepancy between the problem solution and the problem requirement poses a challenge and a need for mathematics and theory, thereby forming a closedloop, iterative learning process. It is noted that, while the problem-driven learning loop is effective in motivating entry-level students, the post generalization procedure is necessary and important for acquiring general, abstract knowledge. In teaching EE-4510 at LSU by the author, the course is led by a pilot design project of an industrial control problem-a voice-coil DC motor drive system for a computer disk drive read-write head position control, which is assigned at an early stage and continued throughout the course. The project is used to pose challenges to the students at various stages of the course, thereby motivating the students for the upcoming mathematical treatment and theoretical study. The dissemination of the theoretical contents of the course has to be reorganized to accompany each stage of the design process, and to focus around the need of the pilot project, with provisions of generalization and further
For instance, as the disk drive control project is handed out to the students, the evolution of disk drive technology, from the st-inch, full-height, single-side, single-density (90 KB) floppy disk drive to today's credit-card size hard disk drive, and its impact on the advancement of personal computer technology are introduced. A 5{ -inch, half-height, double-side, double-density (360 KB) floppy disk drive and a notebook computer are presented to the students, where the latter is twice the size of the floppy disk drive, but fully equipped with a 3~ -inch double-side, high-density (1.44 MB) floppy disk drive, an 80 MB hard disk drive, in addition to the keyboard, built-in mouse, VGA LCD screen, battery and 486 CPU. While the students are amazed by the technological advancement taken place in the past decade,
1 Beginning Spring, 1994, the first control course is changed to EE-3530 taught at junior level. The new approach is being applied to teaching this course by the author at the time of writing.
88
the demand of this advancement on control engineering is explained. Increased disk density and access speed require higher control precision (reduced steady-state error) and fast transient performance, while reduced size and energy consumption call for optimally designed and implemented controllers, actuators and sensors. At this time the students are fully charged up and eager to meet the challenge.
tor-amplifier block-diagrams are the closest simulation to physical implementation using available electronic components. The reasons that transfer function blocks or procedural simulation (such as MATLAB® programs) are not favored for entry level students are: (i) transfer function blocks, as presently implemented in most block-diagram simulation software packages, such as MATLAB-SIMULINK®, VisSim®, do not allow simulation of natural (zero-input) response of the plant, (ii) transfer function blocks, and similarly procedural simulation programs, simplify mathematical expressions at the cost of obscuring physical intuition. For the purposes of stimulating the students, the author has had very positive experience with VisSim.
To facilitate the understanding of the problem and the project assignment, a radical change in the lecture contents has to be made, namely the typical dynamical behaviors and performance indexes such as the overshoot, settling-time, steady-state error, etc. need to be introduced before even mentioning about such topics as damping ratio, natural frequency, etc. But this can be easily achieved when the physical meanings and commercial/economical consequences of such performance indexes are explained with respect to the pilot project.
Both the idealized (linear time-invariant) model and a more accurate model (nonlinear, timevarying, with noise and disturbances) should be built to show the differences. This will serve the purpose to motivate the students for further study of advanced topics in control. The need for further analysis and compensation of the dynamical behavior of the plant should be revealed through simulation studies.
!.!. Claalleate 0/ mo"e1iat. The need for quantitatively modeling the system /process to be controlled, i.e. the plant, comes naturally as the necessary first step of the design process, differential equations, transfer functions, signal flow graph, state equations, etc. are readily acquired by the students. Modeling of nonlinearities, time-dependence and uncertainties of the plant, noises and disturbances in the operating environment should also be treated here at appropriate levels, such as linearization, slowly time-varying assumption, or simply mention but ignoring some aspects, such as sensor noise, and leaving them to later simulation studies of the their effects on system performance.
!.-I. Claalleate o/.a."m. While the modeling process is certainly a mathematical challenge to entry level students, the analysis is the grand challenge. One of the best way to motivate the students to commit themselves to and to endure such an undertake comes from the frustration and failure of the most intuitive and straightforward de!'igll method: design by trial-and-error without any theoretical insight and guidance. The intuitive concept that the system parameters (the coefficients of the differential equations) determine the system behaviors and state-feedback can be used to alter these parameters (of course with the unrealistic assumption that all the state variables are directly measurable) are readily accepted by the students, and a trial-and-error design is assigned to the students. As the students getting frustrated with the experimentation, theoretical development of analytical solutions, criteria for stability, controllability and observability are introduced. At this stage, a more advanced trial-and-error design based on the idea of eigenvalue (pole) assignment is assigned to further challenge the students for a systematic development of controller design techniques.
!.3. Claalleate 0/ nmal.tiOfl. The need for validating the mathematical model of the process, and the possibility of studying the behavior of the plant without having to physically build it leads to the introduction of computer simulation techniques. Theoretical development accompanying this stage is the various (canonical) realization techniques. Although many control simulation software packages are commercially available, it is believed one that implements the model using blockdiagrams of integrators, and linear/nonlinear amplifiers (not transfer function blocks) serves the purpose best. This is because: (i) blockdiagram simulations can be built directly from the various (canonical) realizations developed in the lectures, (ii) once the physical implementation of an integrator and an amplifier using an operational amplifier is explained, such integra-
!.5. CIa.ueate
0/ "enp.
Upon addressing the need for dynamical feedback control, such as integral feedback for improved steady-state accuracy, state observer for inaccessible state variable measurements, the 89
various control techniques for linear timeinvariant systems can be summarized as the aids for selecting the "optimal" locations of the eigenvalues of the overall closed-loop system. By now the students should be ready to accept at any price any design technique that will help them to get out the seemingly hopeless trail-and-error design practice. Many real world issues revealed in the design project, such as tradeoffs between transient performance and steady-state accuracy, transient performance and robustness, overall performance and control energy consumption, model accuracy and ease of analysis, serve as motivations for the students to undertake further studies of advanced control topics such as optimal, robust and nonlinear control.
the most time-consuming part of the project and also the most frustrating for me. I was eventually led into writing a computer program that would find a satisfactory K matrix for me. I wrote the program in MATLAB ... However, I had to learn much about MA TLAB in order to write the program. (This is part of the overall knowledge I gained from the project.) ... The fact that I was able to program the computer (and the program succeeded) to find the optimum K for the systems was very gratifying. (R.
A. Richard)
2) In completing this project, I feel a great sense of accomplishment and that my money has been well spent in pursuing a degree in electrical engineering. Now, I say on to EE~580 (a second control course on classical design techniques). (C. Fontenot)
3. SUMMARY AND CONCLUSIONS
9) I found this project (Project 11) to be a great learning experience .... My after thoughts on this project center around one question: can my design actually be built'l •..1 guess one day, after my retirement and (having) a lot more experience, I'll pull out these two project reports that I did in controls and actually attempt to build it. Before I took the controls class, I felt that controls might be the field I would like to specialize in. After these projects I feel more strongly. (D. BourgeoIs)
After some painstaking experimentation and with the enthusiastic support from the students, this new teaching approach has achieved marked success as indicated by: (i) drastically increased grades of many students during the course; (ii) enthusiastic comments from the students at the end of the project (cf. student quotations shown below); (Hi) self-initiated, unsupervised exploration by the students (cf. Quotation 1 shown below); and (iv) a great increase in the enrollment of subsequent technical elective courses in controls. Problems with this new teaching approach include: (i) excessive time spent by the students on the project; (ii) frustration due to repeated failure; (Hi) synchronization between the design process and the theoretical development. These problems are believed to be solvable by further improvement of the project assignment and the accompanying lectures, and a finetuned balance between student self-exploration and instructor assistance. For the latter, it is felt that the instructor needs to be vary sensitive to signs of frustration of the students, and to establish at an early stage complete confidence and trust among the students. Another improvement is to include an accompanying laboratory course, which is not presently available at LSU.
4. REFERENCES Masten, M.K. (1991). An industrial challenge to control system educators, Proceedings, IFA C Conference on Advances in Control Education, Boston, MA, U.S.A.
Dorato, P., and A. Feliachi (1991). Control systems curricula in the United States: results of two recent surveys, Proceedings, IFA C Conference on Advances in Control Education, Boston, MA, U.S.A.
Yurkovich, S. (1992). Advances in control education, IEEE Control Systems Magazine, Vo1.12, No.3, 18-21. Kuo, B.C. (1991). Automatic Control Systems, 6th Ed., Prentice-Hall, Englewood Cliffs, NJ. U.S.A. Dorf, R.C. (1992). Modern Control Systems, 6th Ed., Addison-Wesley, Reading, MA., U.S.A. Nise, N.s. (1992). Control Systems Engineering, Benjamin/Cummings, Redwood City, CA, U.S.A.
The author wishes to conclude this paper by sharing the following gratifying comments from the students: 1) A nother positive reflection I have is that the projects have raised my interest in the area of control systems, ... My interest was raised so much that I plan to take another control systems class in the future .... Finally, the one area of the project that captured my attention the most was finding a K matrix that allows the closed-loop system to perform up to the design requirements. The search for this optimum K matrix became
Ach01llleflgemeat. The author sincerely thanks Dr. J. L. Aravena, ECE Department, LSU, for his enthusiastic support and help in experimenting with the motivation-by-challenge teaching approach and in writing this paper. 90