Linking Industrial Research Projects and Educationpeople.cst.cmich.edu/yelam1k/asee/proceedings/2015/paper... · 2015-04-07 · 2 Fiat Chrysler Automobiles (FCA), Auburn Hills, MI

Proceedings of the 2015 ASEE North Central Section Conference Copyright © 2015, American Society for Engineering Education

Linking Industrial Research Projects and Education

Andrew Rusek1, Michelle Merrifield2, Subramaniam Ganesan1, 1 Department of Electrical and Computer Engineering

Oakland University, Rochester, MI 48309

2 Fiat Chrysler Automobiles (FCA), Auburn Hills, MI 48309

Emails: [email protected], [email protected]

Abstract:

Industrial research projects related to automotive and industrial electromagnetic compatibility problems, such as vehicle grounding, vehicle controller area networks (CAN), and shielded and unshielded twisted pair cables have led to establishing two very popular elective graduate courses, such as Instrumentation and Measurements and Electromagnetic Compatibility (EMC). The course materials of these courses are based on several industrial projects such as generators and gigahertz sampling oscilloscopes.

This paper describes a few experiments added to the course of Electromagnetic Compatibility. These experiments were developed to help understand the differences between the performance of the shielded and unshielded twisted pair cables applied in automobiles and in industrial robots. The other experiments, included in this course demonstrate sinusoidal and pulse performance of coaxial cables , radiated emission tests, applications of Line Impedance Stabilization Network to test conducted emissions, and the test of the “spike” generator, which was also used to check the EMC performance of the twisted pair cables described in this paper.

The student evaluations clearly indicate improvements in meeting the course outcomes. The comments in the course evaluations to the question on the above projects indicate that the students received a greater understanding of the topics like radiation, conduction and cross talk thanks to these experiments.

Introduction

Very fast developments of new electrical engineering research applications in automotive industry have led to stronger connections between our faculty and engineering development personnel of local industry where new technologies have been implemented. Some of the intermittent failures are due to electro-magnetic radiation of shielded and unshielded twisted pair


cables in CAN network in vehicles.. We did some experiments and simulations to compare the cable performance of these two technologies, and we introduced more information to our graduate course of Electromagnetic Compatibility. A brief course description is shown below.

Topics: Overview of EMC, EMC Requirements, Review of Electromagnetic Principles, Distributed and Lumped Components, Signal Spectra and Spectrum Measurements, Introduction to EMC Pre-compliance and Compliance Tests, Component and System Level Measurements, Radiated Emissions and Susceptibility, Conducted Emissions and Susceptibility, Crosstalk, Shielding and Guarding, Electrostatic Discharge, Introduction to System Design, Introduction to Signal Integrity. The course outcome and course outline are given in the appendix.

We did a number of industrial development projects for the local auto industry. From this experience we chose a few experiments and added them to our graduate courses. These experiments gave the students a better understanding of the theory and applications. Most of our graduate students are working in automotive industry and they appreciate practical experiments as part of the course to augment the theory. Some of the experiments are mentioned below.

At the end of the paper we have a section on how this addition of experiments helped our students’ performance in the courses and also in their work.

Twisted Pair Cable Test Results Presented in the Course

The measurement results of the twisted pair cables are presented to enhance theory and simulations applied to show the radiated emissions, crosstalk effects and shielding,

At the beginning of the studies it was interesting to check how effective the coaxial cable screen could be when the screen was grounded at the cable input and the output.

Shielded Twisted Pair Cable (STP) maintains the signal-carrying wires inside a conducting shield. This fact would suggest that inside the shield, all external interference is automatically blocked, especially when both ends of the cable shield are properly grounded. The shield also is subjected to the action of interfering electromagnetic field and the interfering sources are coupled to the cable shield and also to the center conductors of the cable. Magnetic field part of interfering field creates a potential for intrusive current compensation, but electric, also called a capacitive interfering field component still exists. Shield, unfortunately cannot be grounded over its entire length, so at least capacitive component of interfering signal can reach the center of the shield. In the first part of the article text, the results of a simple experiment illustrate performance of coaxial cable in comparison with behavior of an unshielded single wire located above the ground plane. The results of tests of shielded and unshielded twisted pair cables operating in the structure used to measure the coaxial cable are described in the paper.


.

. Shielding Effectiveness Tests

Fig. 1 The diagram of the circuit used to check shielding effectiveness of the coaxial cable


f = 10 MHz, Channel1 INPUT, Channel2 Coaxial Cable, Coax, (Far-‐End, FE), Channel3 Single wire, Ch4 Coax (Near-‐End, NE) Fig. 2 10 MHz signal test results of the coaxial cable

62 MHz, Channels Ch1 INPUT, Ch2 Coax (FE), Ch3 Single wire, Ch4 Coax (NE) 10 MHz, First three channels as before, Ch4 shows Center of the shield voltage Fig. 3 62 MHz (left) and 10 MHz (right) signal test results of the coaxial cable. The 10 MHz Test results show the signal observed on the shield of the coaxial cable


Shielded and Unshielded Twisted Pair Cable Tests

Measurement Circuit

The circuit includes the single wire above the ground cable (GENERATOR WIRE), which is connected to the Spectrum Analyzer internal generator sweeper (to 1.5 GHz), and parallel twisted pair cable with four outputs (two NEAR END and two FAR END). The four output signals are measured and registered by means of the Spectrum Analyzer. The simple cable structures were chosen to limit the effects of potential installation problems related to grounding and existence of cable “tails”. The signals used to test include: sine waves, pseudo-random waves, fast pulses, and high voltage narrow pulses.

Fig. 4 Measurement circuit diagram (The Shielded Twisted Pair, STP, is shown, Unshielded Twisted Pair, UTP, does not include the third bottom ground connections) Measurement Results The following figures show four out of sixteen samples of the measurement results to demonstrate basic differences in UTP and STP cable performance.


Fig. 5 Unshielded (UTP, NE, Fig. 6 Shielded Twisted Pair (STP)

Left wire (L) signal levels NE, L wire signal levels (frequency

(frequency up to 1.5 GHz) up to 1.5 GHz)

Fig. 7 UTP, FE, R wire signal Fig. 8 STP, FE, R wire signal (Frequency up to 203 MHz (frequency up to 202.9 MHz) Common Mode and Differential Mode Interference Comparing the UTP with STP cable responses for NE, L (Figs 5 and 6), and FE, R (Figs 7 and 8), it is possible to observe that the larger levels of common mode interfering signals occur in the STP cable (-20 dBm), whose shield is grounded on both sides of the tray (input and output) while UTP cable had -30 dBm common mode interference level in the same conditions.

Fig. 15 STP, FE, R wire signal (Frequency up to 202.9 MHz)


The graphs for shielded twisted pair transmission lines (STP) show similar level differences, but the maximum common mode interference level of – 20 dBm was registered, which is larger than the maximum common mode interference level for UTP operating in the same conditions. At higher frequencies maximum differences reach about 0.5 divisions, which correspond to 5 dBm. At lower frequencies, around 150 MHz, the difference is larger, reaching about one division (10 dBm). STP lines show then a bit better performance at frequencies closer to 1.5 GHz. Higher levels of common mode interfering signals observed in STP lines at some frequencies suggest that the shield coupling to the interfering wire signals is strong, even if the shield is grounded on both sides of the cable. Also the strong coupling of the shield and internal twisted pair cable increases the level of common mode signal. On the other hand, the differential mode interference signal is almost the same as the one for the UTP line, which shows better symmetry of the twisted pair lines inside the shield. Shielded and unshielded TPs, to compare selected results for noise generator tests (for comparison with Spike Generator Tests)

Fig. 7 Noise generator test (STP) Fig. 8 Noise generator test (UTP) Common mode, shielded, NE (R) Common mode, unshielded, NE(R) Shielded TP appeared to reduce the spike noise signal four times more than unshielded TP. This suggests that sudden discharges near the UTP transmission lines can interfere stronger than the ones near UTP transmission lines. According to some professional literature, more attention should be paid to proper separation of UTP lines from higher voltage supply lines and from other sources that could produce high voltage surges.


Fig. 9 Unshielded, Ch. 1 single wire Fig. 10 Shielded, Ch. 1 Single wire interfering signal Interfering signal Ch. 2 NE (L), Ch. 3 NE (R) Ch. 2 NE (L), Ch. 3 NE (R) Shielded TP appeared to reduce the spike noise signal four times more than unshielded TP. This suggests that sudden discharges near the UTP transmission lines can interfere stronger than the ones near UTP transmission lines. According to some professional literature, more attention should be paid to proper separation of UTP lines from higher voltage supply lines and from other sources that could produce high voltage surges. Other Time-Domain Test Results Immunity and radiation tests were performed using the pulse generators and the multichannel scope. Immunity test results


Fig.11 Immunity test, Shielded TP, Channel 1 – single wire input signal NE, Channel 2 NE Left wire (L) signal, Channel 3 NE Right wire(R) signal, Rise time=fall time=20ns, pulse width 60ns, Channel 4 – single wire output signal FE.

Fig. 12 Immunity test, Unshielded TP, Channel 1 – single wire input signal NE, Channel 2 NE Left wire (L) signal, Channel 3 NE Right wire(R) signal, Rise time=fall time=20ns, pulse width 60ns, Channel 4 – single wire output signal FE. Radiation Tests Results

Fig. 13 Radiation test, Unshielded TP, Ch1 NE, single wire receiver, Ch4 FE, single wire receiver, Ch2 Negative signal, NE L, Ch3 Positive signal, NE R, rise time=fall time=10ns, Pulse width=60ns


Fig. 14 Radiation test, Shielded TP, Ch1 NE, single wire receiver, Ch4 FE, single wire receiver, Ch2 Negative signal, NE L, Ch3 Positive signal, NE R, rise time=fall time=10ns, Pulse width=60ns

Fig. 15 Radiation test, Unshielded TP, Channels as before, Rise and Fall times=20ns, Pulse width=60ns

Fig. 16 Radiation test, Shielded TP, Pulse parameters as for the previous figure


Student Participation in Experiments The students attending the EMC (Electromagnetic Compatibility) course have a chance to participate in demonstrations of experiments and they could also get familiar with all instruments to measure the most important parameters of the signals. In the same course, the other experiments have been also included, as described in the listed references [9] and [10]. In addition to measurements, the students use PSPICE software program to model the twisted-pair transmission lines and make some predictions. Some additional information is included in [6, 7, 9, 10, and 11]. How the Students Benefit from this Approach The experiments introduced in the course thanks to our research at industry have made the course material easy to understand and fun to learn the application of EMC theory. The student feedback shows that these experiments gave the students a better understanding of the theory and applications. Most of our graduate students are working and they appreciate practical experiments as part of the course to augment the theory.

The course evaluations on the course outcomes received very good results. The student comments to course survey indicate that the students very much learned from the demonstrations and experiments in the class. Our homework, and exam answers clearly show the full understanding by almost all the students thanks to the experiments.

Some students sent emails stating that they applied these experiments and the theory learned from the course in their industry. At the end of the course, we do a survey of the course content and delivery of the content of graduate courses by external evaluators/ experts. The external evaluators were very happy to see the addition of these experiments to clarify and show the application of the theory in these courses.

As per the alumni letters, the described projects and their interpretation are very helpful to the working graduate students, and they could apply some of the demonstrated ideas in their company. Some of the students joined electromagnetic compatibility laboratories with the knowledge reinforced by the experiments. The employer letters indicate that our alumni have used the knowledge gained from these experiments in the industry to rectify many of the problems in the design.

Some student comments from a couple of semesters from the past (Fall 2013 and Fall 2014) are given below. “Outstanding instructor, great examples and motivating. Great class”.


“He is a really good professor that knows his material. The course was good, I learned a lot from it with the demos and experiments in the class”. “Awesome, The EMC course applies directly to my area of expertise at the work place and it is a very valuable course. The experiments he showed in the class were excellent”. “Instructor explains the material very well and provides examples and experiments in the class to demonstrate the theoretical concepts, handouts, practice problems. Professor also provides a sample test to practice on before the test”. “All engineers must take this course. Great demonstrations are provided in the class. Very informative for real world applications are demonstrated”. “Interesting course. It helped that I was doing EMC testing at work to see how our teachings can be applied”. “Informative course, brings the interest in electromagnetics and lets you think in a lot more details regarding the effect of electromagnetic signal on its surrounding”. Thanks to the introduction of the experiments in the class, the enrollment in the course doubled from the previous years since the students find the course more interesting and useful.

Conclusion

This paper describes a few experiments added to the course of Electromagnetic Compatibility. These experiments were developed to help understand the differences between the performance of the shielded and unshielded twisted pair cables applied in automobiles and in industrial robots. The evaluation of the performance and usefulness of the addition shows that there is now more understanding of the theory by the students. Student comments are very encouraging and appreciative of the in class demonstrations. The student enrollment also increased due to the usefulness of the experiments and enthusiasm it has created.

References

1. Lee, R. (2004) Research and teaching: making – or breaking – the links, Planet, 12: 9-10. 2. Barnett, R (ed) (2005) Reshaping the University: New Relationships between Research, Scholarship and Teaching. McGraw Hill / Open University Press, pp.67-78 3. John Hattie and H.W. Marsh, “The relationship between Research and Teaching: A meta analysis” Review of educational research, Winter 1996, Vol. 66. No 4. pp 507-542. 4. Alan Jenkins et al., Linking Research and Teaching in disciplines and departments, April 2007, 100 pages http://www.heacademy.ac.uk/assets/was%20York%20-%20delete%20this%20soon/documents/ LinkingTeachingAndResearch_April07.pdf#page=1&zoom=auto,0,842 5. Dr Esat Alpay and Ms Rianne, Practices and approaches for the integration of teaching and research, http://www.heacademy.ac.uk/assets/documents/stem-conference/Engineering1/Esat_Alpay_Rianne_Verschoor.pdf 6. Andrew Rusek, Subra Ganesan, Barbara Oakley, “Improving Student Understanding of Instrumentation and Measurement in US Engineering Undergraduate Programs”, ASEE NCS, April 3-4, 2009, Grand Rapids, Michigan. 7. Subra Ganesan, “A course on Automotive embedded system analysis, verification, and validation”, ASEE NCS, April 3-4, 2009, Grand Rapids, Michigan.


8. Andrew Rusek and Subramaniam Ganesan, “Bridging communications systems and circuits with Pspice”, ASEE, NCS conference, Pittsburgh, March 26-27, 2010 9. Andrew Rusek, Dan Aloi, Subramaniam Ganesan, “A friendly approach to transient processes in transmission lines” ASEE NCS conference, April 1, 2011. 10. Andrew Rusek, Subramanian Ganesan, Barbara Oakley, Daniel Aloi, “Time-Domain Reflectometry (TDR) in Graduate Courses”, ASEE NCS, March 23, 2012. 11. Andrew Rusek, Michelle Merrifield, Subramaniam Ganesan, “Combining Research and Teaching in Order to Attract More Students, Proceedings of the 2014 ASEE North Central Section Conference Copyright © 2014, American Society for Engineering Education

Appendix:

EMC course outline with course outcomes

Course Title ECE 546 Electromagnetic Compatibility The course belongs to the Electromagnetics ECE option. (ABET a, e, g, i, j, k) Course Level: Graduate. Total Credits: 4 Prerequisites by Topics: Static and dynamic electromagnetic fields, analysis of electronic circuits, signal analysis. Catalog Course Description: Review of EM basics related to EMC applications. Analysis of EMI sources and receivers. Signal spectra, conducted and radiated emissions. Transmission line cross-talk. Introduction to shielding, filtering, and grounding. Electrostatic discharges (ESD). Circuit and system immunity. Signal spectra, conducted and radiated emissions. EMC requirements for component and system levels. US and European standards and their origin. Automotive EMC standards. EMC issues in vehicle multiplexing communication. Several laboratory experiments are demonstrated. Prerequisites: Undergraduate courses in electronic circuit design, electromagnetics, and communication systems Textbook: C. R. Paul, Introduction to Electromagnetic Compatibility, J. Wiley, Recent Edition References: Henry W. Ott, Noise Reduction Techniques in Electronic Systems, J. Wiley, 1988 David R. Weston, Electromagnetic Compatibility, Marcel Dekker, Inc., 1991 Paul A. Chatterton and Michael A. Houlden, EMC Electromagnetic Theory to Practical Design, J. Wiley, 1992 Howard Johnson, Martin Graham, High-Speed Digital Design, A Handbook of Black Magic, Prentice Hall, 1993 Mark I. Montrose, Printed Circuit Board Design Techniques for EMC Compliance, IEEE Press Topics: Overview of EMC EMC Requirements (i, j) Review of Electromagnetic Principles (a, e) Distributed and Lumped Components Signal Spectra and Spectrum Measurements (a, e, k) Introduction to EMC Pre-compliance and Compliance Tests, Component and System Level Measurements (e, k) Radiated Emissions and Susceptibility (a, e) Conducted Emissions and Susceptibility (a, e) Crosstalk (a) Shielding and Guarding (a) Electrostatic Discharge (a) Introduction to System Design (a, e, i, j, k) Introduction to Signal Integrity, TDR (a) Course Outcomes:


The students obtain the following competencies: - Understanding of the US and foreign EMC standards. - Understanding of the time and frequency representations of signals. - Ability to evaluate parameters of electronic components at high frequency. - Ability to evaluate the design factors that contribute to conducted emissions, radiated emissions, and crosstalk. Some topics are supported by the laboratory demonstrations. Computer Usage: Students regularly use PSPICE and MATLAB to verify their calculations and solve numerically more complex problems. ABET outcomes: Engineering programs must demonstrate that their graduates have: (a) an ability to apply knowledge of mathematics, science, and engineering (b) an ability to design and conduct experiments, as well as to analyze and interpret data (c) an ability to design a system, component, or process to meet desired needs (d) an ability to function on multi-disciplinary teams (e) an ability to identify, formulate, and solve engineering problems (f) an understanding of professional ethical responsibility (g) an ability to communicate effectively (h) the broad education necessary to understand the impact of engineering solutions in a global and societal context (i) a recognition of the need for, and an ability to engage in, life-long learning (j) a knowledge of contemporary issues (k) an ability to use the techniques, skills, and modern engineering tools necessary for engineering practice Biography

Subra Ganesan ([email protected]) is a Professor of Electrical and Computer Engineering at Oakland University and Director of Real Time Embedded DSP Systems Lab. He joined the university in 1984. After graduating from Indian Institute of Sciences Bangalore India, he served at universities in Germany, and Canada and Indian research laboratory as a scientist. He does research work in collaboration with TI, Free Scale, and a few automotive companies and US army. His research areas include DSP, Embedded Systems, Real Time Systems, Condition-based Maintenance, and Optimization.

Andrew Rusek ([email protected]) is a Professor of Engineering at Oakland University in Rochester, Michigan. He received an M.S. in Electrical Engineering from Warsaw Technical University in 1962, and a PhD. in Electrical Engineering from the same university in 1972. His post-doctoral research involved sampling oscillography, and was completed at Aston University in Birmingham, England, in 1973-74. Dr. Rusek is very actively involved in the automotive industry with


research in communication systems, high frequency electronics, and electromagnetic compatibility. He is the recipient of the 1995- 96 Oakland University Teaching Excellence Award

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Linking Industrial Research Projects and Educationpeople.cst.cmich.edu/yelam1k/asee/proceedings/2015/paper... · 2015-04-07 · 2 Fiat Chrysler Automobiles (FCA), Auburn Hills, MI