Session T2D INTEGRATING THE INTERNET, MULTIMEDIA COMPONENTS, AND HANDS-ON EXPERIMENTATION INTO PROBLEM-BASED CONTROL EDUCATION Malgorzata S. Zywno and Diane C. Kennedy Department of Electrical and Computer Engineering, Ryerson Polytechnic University, Toronto, Ontario, Canada, M5B 2K3
Abstract - At the brink of a new millennium, a shift in pedagogy toward a learner-centered approach is emerging, where critical thinking skills are fostered through problembased learning opportunities and innovative approaches to instruction and student work assessment. New media technologies are being effectively used to help achieve such goals in engineering education. This paper describes technology-aided teaching of undergraduate engineering courses in control theory. Early results show that students are better motivated and their achievement improves compared to when more traditional methods of instruction are used in delivering the course content.
• • • •
INTRODUCTION The mandate of Ryerson Polytechnic University is to focus on the provision of a strong applied undergraduate education. To this end many programs are exploring innovative teaching methods and incorporating technology -enabled instruction techniques in and out of the classroom. This paper focuses on course instruction for Electrical and Computer engineering, and expands on the work previously reported in [1]. Course emphasis is placed not only on the provision of a solid theoretical foundation, but also on the extension of the theory to practice. For example, attention is paid to implementation aspects and the recognition and treatment of practical system properties, such as non-linearity, for which the theory will not suffice. Real-time experiments and realistic design, testing, and implementation using advanced computer simulations (MATLAB and Simulink1) are an integral part of the courses in and outside of classroom [2]. The courses reviewed include: • ELE322 - Electric Networks, which provides instruction in basics of network analysis and filter design and introduces students to the networked computing environment, including OrCAD PSpice circuit analysis software2; • ELE532 - Signals and Systems, which provides instruction in the fundamental mathematical tools required for all process
control, signal processing, and communication courses that follow; ELE639 - Control, which is an introductory course in classical linear control theory 3; ELE749 - State Space Control Systems, which is a follow-up course in state space control, ELE829 - System Modeling and Identification, which offers an introduction to topics in modern linear system identification, and PID Control - Course for Industry, which is an intensive, twoday course [3], developed to bridge the gap between academia and the needs of industry. This course focuses on practical aspects of industrial process control.
INCORPORATING M ULTIMEDIA ELEMENTS IN LECTURE M ATERIALS Much of the theory of process control relies on the understanding of some fairly complicated mathematical concepts. We find that it is much easier to properly teach these concepts to students when one is not limited to classic teaching methods. Along with a need to grasp abstract concepts, the students must also gain an understanding of the process of practical system design. This is inherently an iterative process with many tradeoffs involved. Understanding can be greatly enhanced by introducing new media to illustrate the approach taken and to display intermediary results. In general, all of the courses listed above use a mix of computer simulations, Java Applets and graphics to supplement classroom instruction and to provide visualization of the theory. Moreover, two of the courses (ELE639 and PID Control for Industry) have all lectures delivered using hyper-linked text combined with video clips, interactive graphics and applets, screen captures and computer simulations, to replace, rather than supplement, the traditional instruction, and to illustrate real-life implementations. Several examples of the effective use of multimedia for each of the courses are now described in greater detail.
1
MATLAB and Simulink are registered trademarks of MathWorks, Inc. (http://www.mathworks.com) 2 OrCAD PSpice is a registered trademark of OrCAD, Inc. (http://www.orcad.com)
3
General information on the course and a demo module are available at: http://www.ryerson.ca/~ele639
0-7803-6424-4/00/$10.00 © 2000 IEEE October 18 - 21, 2000 Kansas City, MO 30 th ASEE/IEEE Frontiers in Education Conference T2D-5
Session T2D Introduction to Control (ELE639) For students with no frame of reference and a yet-to-be defined "control jargon", pictures and video clips of real life control systems, such as industrial robots, serve to provide examples and a visual, intuitive understanding of what exactly is process control. Using multimedia as an alternative to a "real-life" demonstration has the advantage of being portable, faster, and able to showcase a variety of processes including unstable systems, where duplicating the experiment is not recommended, for obvious reason. In addition to using material freely available over the Internet, QuickTime movies of several laboratory-scale setups of physical systems were specifically created for the use in the course. These include an inverted pendulum, a flexible joint (shown in Figure 1), a three-degrees-of-freedom helicopter simulator and two different servo-positioning systems.
Figure 2: Java Applet for Pole-Zero Manipulations5 MATLAB "movies" were also created to illustrate relationships between pole locations, model parameters and system response. Both of these visualizations are embedded in the HTML pages and can be accessed with nothing more than a browser as a tool. Convolution (ELE532)
Figure 1: Flexible Joint Experiment 4 In each case, there are difficult mathematical concepts, which must be clarified for the student. We now review these some of these concepts, and illustrate how multimedia techniques can be employed to enhance understanding. Pole/Zero Locations and their Effect on System Response (ELE639) Using a classic approach, one faces a tedious task of sketching diagrams, or at best showing static overheads, of the system response for various pole locations. Contrast this with the much more illustrative means provided by Java applets (such as the one shown in Figure 2) which allows one to move the singularities around in the complex plane, and immediately see the results on system time or frequency responses.
One of the most important mathematical concepts that must be understood is the convolution operation, as this is an important representation of the inherent system characteristics. Traditional approaches for performing this operation include analytic, graphical, and tabular forms. When combined with an interactive graphical approach, implemented using a Java applet 6, the student is able to visualize exactly what is happening to the signals involved. Controller Design (ELE639, ELE749) MATLAB and Simulink files are executed during lectures, providing simulation results as an instant illustration of topics discussed. This is especially helpful when discussing different aspects of control design, as in case of a lead-lag compensation and PID controller tuning in ELE639, or of a robust state space controller and observer design in ELE749. QuickTime videos clips, and/or a VHS tape recording of the process behaviour under control are also used to reinforce the concepts. Effects of Sampling (ELE532) It is important that students understand the significance of continuous time signal representation by a discrete time
5
4
The Flexible Joint Experiment was developed by Quanser, Inc., http://www.quanser.com
WWW Java Applet by Brian Woo, http://www2.ece.jhu.edu/wjr/explore/index.html 6 WWW Java Applet by Steve Crutchfield, http://www2.ece.jhu.edu/wjr/convolve/index.html
0-7803-6424-4/00/$10.00 © 2000 IEEE October 18 - 21, 2000 Kansas City, MO 30 th ASEE/IEEE Frontiers in Education Conference T2D-6
Session T2D approximation, particularly when continuous time control algorithms are implemented by computer algorithms via A/D and D/A communication with the process. A Java applet (shown in Figure 3) is used to demonstrate the effect of the aliasing that occurs when signals are sampled too slowly.
Figure 3: Java Applet to illustrate Aliasing7 The key is the visualization afforded by the applet which allows the student to "see" how the signal spectrum moves closer and closer together as the sampling becomes slower, and to comprehend how the confusion between low-frequency components and high-frequency components arises. Filter Design (ELE322, ELE532) When designing for system performance to signals that are not easily characterized by a time-domain representation, it is necessary to re-characterize the signal, for example, via its truncated Fourier series representation. The number of terms used to characterize signals is often related to the percentage of the total energy of the signal that is contained in its Fourier series approximation. Often, this characterization seems quite abstract, so a Java applet 8 once again become handy as a tool to immediately show what the addition of each component provides in terms of 'better' signal approximation. OrCAD PSpice and MATLAB simulations are also used to illustrate the filter response in time and frequency domain.
HANDS -ON EXPERIMENTATION Currently two courses (ELE639 and PID Control for Industry) have a real-time control lab component. Hands-on sessions involve application of the discussed concepts in real systems, including data collection, modeling, effects of system non-linearity including control signal saturation, and effective approaches for controller tuning. The controller designs are tested using Simulink computer simulations to provide an expectation of performance. It is then implemented using software, which allows the student to control physical hardware in real time using a pre-packaged interface that removes the need to write additional code. Thus rapid control prototyping and hardware-in-the-loop simulations can be successfully accomplished within time constraints of the courses. In the PID Control for Industry course the proprietary software package WinCon9 is used to provide the real time control. WinCon links the Simulink diagrams to the C code automatically generated by the Real-Time Workshop 10. In ELE639 laboratory, an open code version of real time interface software is used which runs under the Linux operating system. Another project, currently underway in cooperation with an industrial partner, involves a highly coupled, 8th order multiinput/multi-output, 3 degrees-of-freedom helicopter simulator. Currently, undergraduate thesis students use the setup to develop advanced control strategies. Completed projects include a fuzzy logic controller for the helicopter and a Java interface to control the process remotely over the World Wide Web. The eventual goal is for all experiments in the control lab to be accessible over the Net, thus allowing the students the option of completing their lab experiments in asynchronous mode.
IMPLEMENTATION ISSUES All courses are supported by password-protected websites providing course management information, lecture materials, updates, tutorials and software example files that can be downloaded, executed and modified as required. The networked XWindows environment allows also for the instructor and students to share display to conduct guided interactive sessions during tutorial hours. Outside of the classroom, implementing interactivity through the simulation software is a little more complicated, since students must have access not only to tutorials through a browser, but they also require the Student Editions of MATLAB, Simulink and OrCAD PSpice to be simultaneously running on their own computer.
7
WWW Java Applet by Steve Crutchfield,
[email protected] Original WWW Java Applet by Manfred Thole, modified by Tom Huber, http://www.gac.edu/~huber/fourier/index.html 8
9
WinCon is a registered trademark of Quanser Consulting, Inc. Real-Time Workshop is a registered trademark of MathWorks, Inc. 10
0-7803-6424-4/00/$10.00 © 2000 IEEE October 18 - 21, 2000 Kansas City, MO 30 th ASEE/IEEE Frontiers in Education Conference T2D-7
Session T2D In Winter 1999, a WebCT 11 environment was used for on-line course management of ELE639. The WebCT software simplifies the website management and allows such useful features as a bulletin board, on-line surveys and quizzes, as well as downloading course lectures and software files. With the course notes available on-line, students are freed from laborious note taking and participate more fully in classroom discussion. WebCT also allows the student to search for updates on the website, track their grades on-line and collate pages for easy printing.
STUDENT PARTICIPATION In this section, we will focus on the results of incorporating website support in the third year course ELE639. The website for the course provides the major source of reference information for the students. Up to this point, only half of the students (51%) had used the web to some degree in their courses before multimedia teaching techniques were incorporated. However, 83% of students indicated relying on the ELE639 website, and all of the student enrolled in ELE639 considered the website supporting the course effective. A total of 2463 website accesses, and a total of 14,626 individual HTML page hits were recorded for ELE639 Winter 1999 offering, with an average of 257 hits/per student and an average time of 3.6 minutes/hit. This represents an average of 15.4 hours/per student spent accessing the course material, ranging from 1.8 hours to 41.2 hours. Most students (90%) experienced no technical problems accessing the website. While the access was protected with a customized login for each student, enabling them to change their password, the WebCT environment makes it possible for the instructor to track individual students' accesses to different parts of the website. Even though this feature was not used during the duration of the course, all students were made aware of this possibility. This may explain why almost 30% expressed some concern regarding their privacy on the web! Students indicated a preference for one-to-one communication with the instructor through email (i.e., 90% of the students considered it useful or very useful and 93% considered the responses to be prompt) when compared with the one-to-many communications through the website bulletin board (i.e., less than half, 48.3%, considered it useful). 57% of students averaged 1-3 email communications with the instructor per week, and 36% reported less fewer contacts. Most students (86%) accessed the website 1-4 times a week. The reported frequency of face-to-face instructor contacts was similar.
In order to foster the attributes necessary for productive professional practice in the face of rapid technological changes, critical thinking skills, teamwork and lifelong learning skills, and strong problem-solving skills must be developed. A change in the approach to student assessment is also warranted, as discussed in [4]. For example, in ELE829 course, the assessment focuses on measuring achievement through student participation and project work rather than through testing. In both ELE749 and ELE829, student participation and project presentation for peer evaluation is included in the coursework assessment. In all courses new content is introduced and/or reinforced through problem-solving and design work.
EVALUATION OF OUTCOMES IN TECHNOLOGYENABLED LEARNING While the power of integrating new technologies into the classroom as well as for asynchronous and distributed learning is amply demonstrated in literature, reports on formal assessments of the effectiveness of technology -enabled instruction in engineering education are still rare. Evidence of the impact of technology enhanced teaching of ELE639 prior to this study of the Winter 1999 delivery was primarily anecdotal. Instructional materials were developed gradually, starting with labs supported by web-based tutorials in 1997, and ending with WebCT-managed website and multimedia lectures in Winter 1999. In Winter 1999, ELE639 was offered for the first time in full multimedia mode to 57 students, with another 37 students taught using a conventional chalk-and-board approach. This created an opportunity to analyze the impact of technology -enabled instruction on students' outcomes, as contrasted with the conventional approach, and to evaluate their attitudes towards the use of technology [5]. Assessment methodology and surveys were developed as part of a research project, which will continue over two more years. As new media elements were being added to the curriculum, the average final exam mark in the course increased (from 64% in 1996, prior to introduction of new media components, to 77% in 1999). The final exam marks distribution (shown in Figure 4, normalized with respect to the number of students) exhibits a shift from a standard distribution curve towards higher marks.
NEW IDEAS FOR STUDENT ASSESSMENT 11
WebCT is a powerful course management package originally developed at the University of British Columbia, now marketed by Universal Learning Technologies (http://www.webct.com)
0-7803-6424-4/00/$10.00 © 2000 IEEE October 18 - 21, 2000 Kansas City, MO 30 th ASEE/IEEE Frontiers in Education Conference T2D-8
Session T2D
50 45 40 35 30 25 20 15 10 5 0
W 99
W 98
W 97
Pre-media 96
4.7 4.5 Ryerson Engineering Electrical ELE639
4.3 4.1 3.9 3.7 3.5 W96 A
B
C
D
W97
W98
W99
F
Figure 6: FCS Results: Was Instructor Effective?
Figure 4: Final exam marks distribution in ELE639 course at Ryerson (1996-99 data). 4.7
The average grade in the course increased (from 67% in 1996, to 80% in 1999). Similar results are reported in a course in spacecraft design [1] offered in the Department of Aerospace Engineering at Ryerson. These findings are also supported in the Oakley study [6]. All students registered in the course wrote a common 3 hour final exam. The final exam marks distribution for the multimedia group shows a significant shift towards higher marks as compared to the conventionally taught group, as shown in Figure 5 (normalized with respect to the number of students). Results of the 1996-99 annual Faculty Course Surveys (FCS) for ELE639 also seem to indicate an impact of technology -enabled instruction. Figures 6 and 7 show an increase in student satisfaction with the instruction and the course itself, and their levels above averages for the department (ECE), faculty (Engineering) and the university (Ryerson).
4.5
Ryerson Engineering Electrical ELE639
4.3 4.1 3.9 3.7 3.5 W96
W97
W98
W99
Figure 7: FCS Results: Was Course Worthwhile? As Figure 8 shows, students in later years of the course perceived less difficulty, which may be a result of the new instruction technology making the course more accessible. 4.5
50 45 40 35 30 25 20 15 10 5 0
4.3 Multimedia Group
Ryerson Engineering Electrical ELE639
4.1 Control Group
3.9 3.7 3.5 3.3 W96
A
B
C
D
F
Figure 5: Final exam marks distribution in ELE639 course in Winter 1999 - multimedia group vs. control group
W97
W98
W99
Figure 8: FCS Results: Perceived Amount of Course Material Also notable was an improvement in a degree of comfort in using MATLAB/Simulink software as a result of the course, with 84% of students feeling comfortable or very comfortable with the software after the course was completed, compared with only 30% before.
0-7803-6424-4/00/$10.00 © 2000 IEEE October 18 - 21, 2000 Kansas City, MO 30 th ASEE/IEEE Frontiers in Education Conference T2D-9
Session T2D Attitude survey To evaluate attitudes toward the use of multimedia in lectures, asynchronous learning and on-line course management, a 32-item questionnaire was developed, and administered at the end of classes. As Figure 9 shows, students overwhelmingly agreed that the use of multimedia components (86.6%) and computer simulations (93.3%) in lectures help them in faster and better comprehension of the material. 80
1- strongly disagree 3 - agree
[2].
[3].
2 - disagree 4 - strongly agree
70 60
[4].
50 40
[5].
30 20 10 0 Graphics and Java help
Video helps
Overall multimedia useful
Computer simulations help
Fig ure 9: Survey Assessment of Multimedia Components in Lectures
[6].
Journal of Engineering Education, 1999, Vol. 4, No.1, Australia. Zywno, M.S., Kennedy, D.C., "A Practical Servomotor Project: Combining the Web with Simulation Tools to Solidify Concepts in Undergraduate Control Education", Proceedings American Control Conference, July 24-26, 1998, Philadelphia, USA, Vol. 2, pp. 1309-1313. Zywno, M.S., Kennedy, D.C., "An Initiative at Ryerson Polytechnic University in Meeting the Demands of Industry Development of a Multimedia Enhanced Short Course in Practical PID Control for Engineers and Technologists", Workshop at the 1998 ASEE/IEEE Frontiers in Education Conference, November 1998, Tempe, Arizona. Hargreaves, D.J., "Student learning and Assessment are Inextricably Linked", European Journal of Engineering Education, 1997, Vol 4, No. 22, pp. 401-410. Zywno, M.S., Waalen, J.K., "Student Outcomes and Attitudes in Technology -enabled and Traditional Education: A Case Study", Proceedings 3rd UICEE Annual Conference on Engineering Education, February 9-12, 2000, Hobart, Australia. Oakley, B., "A Virtual Classroom Approach to Teaching Circuit Analysis", IEEE Transactions on Education, 1996, Vol. 39, No. 3, pp. 287- 296.
An overwhelming majority, 97.1%, considered taking the multimedia-enabled course worthwhile, while 67% indicated their preference of the technology -enabled classroom teaching over the conventional style. These results are consistent with the 93% approval rate for the course in FCS evaluations (Figure 7).
SUMMARY Our experience shows that hyperlinked text, simulations, animations, videos, images, and sound can facilitate better visualization and comprehension of theory. On-line materials enable students to access information asynchronously (at their own time and pace) outside the lecture room and laboratory. Teamwork, problem based learning and effective communications are emphasized, mirroring demands of real world corporate and professional environments. Students greeted the technology -enabled course with enthusiasm, and overwhelmingly considered multimedia components of the course as helpful in comprehension. Course grades in the multimedia group were improved as compared with the group taught using traditional approach.
REFERENCES [1]. Zywno, M.S., Brimley, W., White, W.E., "Effective Integration of Multimedia Courseware in Engineering Education at Ryerson Polytechnic University", Global
0-7803-6424-4/00/$10.00 © 2000 IEEE October 18 - 21, 2000 Kansas City, MO 30 th ASEE/IEEE Frontiers in Education Conference T2D-10
