A visual, intuitive and engaging approach for explaining the concept of feedback in control systems

Daniel Raviv; Juan David Yepes

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Conference: ASEE Southeast Section Conference
Location: Arlington, Virginia
Publication Date: March 12, 2023
Start Date: March 12, 2023
End Date: March 14, 2023
Conference Session: Mechanical Engineering 1
Tagged Topic: Professional Engineering Education Papers
Page Count: 19
DOI: 10.18260/1-2--44982
Permanent URL: https://peer.asee.org/44982
Download Count: 74

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Paper Authors

biography

Daniel Raviv Florida Atlantic University

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Dr. Raviv is a Professor of Computer & Electrical Engineering and Computer Science at Florida Atlantic University. In December 2009 he was named Assistant Provost for Innovation and Entrepreneurship.

With more than 30 years of combined experience in the high-tech industry, government and academia Dr. Raviv developed fundamentally different approaches to “out-of-the-box” thinking and a breakthrough methodology known as “Eight Keys to Innovation.” He has been sharing his contributions with professionals in businesses, academia and institutes nationally and internationally. He was a visiting professor at the University of Maryland (at Mtech, Maryland Technology Enterprise Institute) and at Johns Hopkins University (at the Center for Leadership Education) where he researched and delivered processes for creative & innovative problem solving.

For his unique contributions he received the prestigious Distinguished Teacher of the Year Award, the Faculty Talon Award, the University Researcher of the Year AEA Abacus Award, and the President’s Leadership Award. Dr. Raviv has published in the areas of vision-based driver-less cars, innovative thinking, and teaching innovatively. He is a co-holder of a Guinness World Record. He is a co-author of five books on innovative thinking and teaching innovatively.

Dr. Daniel Raviv received his Ph.D. degree from Case Western Reserve University in 1987 and M.Sc. and B.Sc. degrees from the Technion, Israel Institute of Technology in 1982 and 1980, respectively.

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Juan David Yepes

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Abstract

Many students consider their first class in Control Systems to be “just another math course”, without comprehending its connection to practical engineering. Part of the reason is a lack of intuitive explanations of real-life physical examples in textbooks. Students may get good grades in the class and yet still miss a deep understanding of modeling, stability, and feedback. In this paper we explain the concept of feedback using visual, intuitive and engaging examples from daily experience, in an effort to help students understand the true meaning of feedback (beyond the “line” in the block diagram) and the physical meaning of the “subtraction unit” in the closed-loop block diagram, i.e., what physical quantities are measured, how they are measured, and what the difference between output and input that results in an error signal looks like in real systems. We address cases where there is no explicit sensor and the error is obtained directly without an “official” subtraction, as well as real-life cases in which the desired reference point is not known. We present an approach that may help students reach the “aha” moment prior to delving into the math. Visual, intuitive, and experience-based examples of feedback systems are presented in which the connection to traditional block diagrams may not be obvious. The examples are grouped into three categories: 1. Mechanical examples, including a Roly Poly toy, where gravity-based feedback leads to a steady state equilibrium, and the flush toilet, which is a self-contained feedback mechanism designed to achieve the desired water level.

The mechanical examples are followed by an engaging hands-on class activity: “the self-balancing wand”, in which the desired end position is not known a-priori, but the feedback error signal is automatically generated.

2. Electrical and electromechanical examples, including the use of bi-metal elements to implement sensing, error and action in air conditioning thermostats, car turn signals, and electric kettles. We explain feedback based on switching between two positions using the example of the electromechanical buzzer, explore the meaning of the feedback resistor in operational amplifier circuits, and present the DC servomotor, where the concepts of sensing, feedback, desired value, and error are all very clear.

3. Human-in-the-loop examples, including escalators, in which riders use visual feedback to compensate for the escalator motion when attempting to move up a down-escalator. We also discuss autonomous driving to explain sensing, error and action signals.

The paper also suggests a set of exercises for students, with a goal of helping them to further capture the essence of sensing, feedback and error signals in real systems. The approach presented in this work has been shared with students in “Control Systems 1” and assessed using an anonymous questionnaire. Initial results from 28 responses indicate that the students preferred being introduced to the topic in a visual and intuitive manner and that they highly commended the approach. This paper should be considered a work in progress. The examples and activities are intended to supplement traditional presentations, and by no means to replace existing textbooks or other pedagogical methodologies.

Citation
Format

Raviv, D., & Yepes, J. D. (2023, March), A visual, intuitive and engaging approach for explaining the concept of feedback in control systems Paper presented at ASEE Southeast Section Conference, Arlington, Virginia. 10.18260/1-2--44982

TY  - CPAPER
AB  - Many students consider their first class in Control Systems to be “just another math course”, without comprehending its connection to practical engineering. Part of the reason is a lack of intuitive explanations of real-life physical examples in textbooks. Students may get good grades in the class and yet still miss a deep understanding of modeling, stability, and feedback.
In this paper we explain the concept of feedback using visual, intuitive and engaging examples from daily experience, in an effort to help students understand the true meaning of feedback (beyond the “line” in the block diagram) and the physical meaning of the “subtraction unit” in the closed-loop block diagram, i.e., what physical quantities are measured, how they are measured, and what the difference between output and input that results in an error signal looks like in real systems. We address cases where there is no explicit sensor and the error is obtained directly without an “official” subtraction, as well as real-life cases in which the desired reference point is not known. 
We present an approach that may help students reach the “aha” moment prior to delving into the math. Visual, intuitive, and experience-based examples of feedback systems are presented in which the connection to traditional block diagrams may not be obvious.
The examples are grouped into three categories:
1. Mechanical examples, including a Roly Poly toy, where gravity-based feedback leads to a steady state equilibrium, and the flush toilet, which is a self-contained feedback mechanism designed to achieve the desired water level.

The mechanical examples are followed by an engaging hands-on class activity: “the self-balancing wand”, in which the desired end position is not known a-priori, but the feedback error signal is automatically generated.

2. Electrical and electromechanical examples, including the use of bi-metal elements to implement sensing, error and action in air conditioning thermostats, car turn signals, and electric kettles. We explain feedback based on switching between two positions using the example of the electromechanical buzzer, explore the meaning of the feedback resistor in operational amplifier circuits, and present the DC servomotor, where the concepts of sensing, feedback, desired value, and error are all very clear. 

3. Human-in-the-loop examples, including escalators, in which riders use visual feedback to compensate for the escalator motion when attempting to move up a down-escalator. We also discuss autonomous driving to explain sensing, error and action signals.

The paper also suggests a set of exercises for students, with a goal of helping them to further capture the essence of sensing, feedback and error signals in real systems.
The approach presented in this work has been shared with students in “Control Systems 1” and assessed using an anonymous questionnaire. Initial results from 28 responses indicate that the students preferred being introduced to the topic in a visual and intuitive manner and that they highly commended the approach.
This paper should be considered a work in progress. The examples and activities are intended to supplement traditional presentations, and by no means to replace existing textbooks or other pedagogical methodologies. 

AU  - Daniel Raviv
AU  - Juan David Yepes
CY  - Arlington, Virginia
DA  - 2023/03/12
PB  - ASEE Conferences
TI  - A visual, intuitive and engaging approach for explaining the concept of feedback in control systems
UR  - https://peer.asee.org/44982
DO  - 10.18260/1-2--44982
ER  -