Internationalof Computational
Intelligence
Systems
Journal ofJournal
Robotics,
Networking andArtificial Life
Vol.
XX(Z);
Month(2018),(Year), pp.
pp. 190–193
xx–yy
Vol.
5(3);
December
DOI:
10.1080/XXXXXXXXXXXXXX;ISSN XXXX–XXXX
onlineDOI:
10.2991/jrnal.2018.5.3.10;
ISSN 2405-9021
print; 2352-6386
onlinehttps://www.atlantis-press.com/journals/ijndc
https://www.atlantis-press.com/journals/jrnal

Research Article

Practice of Control Education by Experiment using Robot
Shinichi Imai1,*, Hideto Matsui2
Technology and Information Sciences, Graduate school, Tokyo Gakugei University, Koganei-shi, Tokyo, JapanKÒSEN National Institute Technology, Hachioji-shi, Tokyo, Japan

12ARTICLE INFOABSTRACT

Article History

In this paper, while control engineering replete with mathematical content is difficult for a beginner to learn, it is a practicalbranch of learning where the control theories expressed by mathematical equations prove useful only after being put into
practice. However, the current status of students’ interest and curiosity in this regard is not favorable based on the impressionthat by learning the mathematical content only it is not possible to comprehend its actual use in practice. Accordingly,
this study proposes an educational method for control systems utilizing robots, with the purpose of developing tools forinculcating interest and curiosity in students on contents such as automatic control and proportional-integral-differential(PID) control. The usefulness of the developed tools is also verified.

Received 1 June 2018
Accepted 12 November 2018
Keywords
Control education
robot
feedback control
practical education© 2018 The Authors. Published by Atlantis Press SARL.
This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

1. INTRODUCTION
In the advanced industrial society of the present day, society is
becoming increasingly global and rapid development in scienceand technology and significant changes in industrial structure aretaking place. Moreover, in recent years, computer (based) control
is being used in various fields spurred by the development in computer technology. Accordingly, control engineering has become
highly important in Japanese industry making it necessary to train
instructors capable of providing control education. Moreover,control technology is being used in almost all equipment, starting from the most familiar things such as air conditioner, electric
pot, and cars to others such as robots, airplanes, and spaceships.
Furthermore, starting from 2012, “measurement and control usingprograms” is being taught as a part of Junior High School curriculum. Accordingly, many studies aiming to enhance control education have been reported [1,2].
However, since control engineering replete with mathematical content is difficult for a beginner to learn, and proves useful only when
the control theories expressed by mathematical equations are actually put into practice, it is a field where experiments bridging theclassroom lectures with practical learning smoothly become indispensable. In teaching control engineering, although the method oflearning the use and usefulness of control theory through simulation on computers is being taught in many universities such as
ours and also in vocational high schools, the current status of thestudents’ interest and curiosity in this regard is not favorable basedon the impression that learning the mathematical content only, it
is not possible to comprehend its actual use in practice. Moreover,in the high school curriculum guidelines (1) on “industry” in* Corresponding author. Email: shimai@u-gakugei.ac.jp“­subjects established mainly in vocational departments,” the subject areas include “electronic measurement control,” in which studyof control basics involving electronic measurement control overview, sequence control, feedback control, and computer control isincluded. Accordingly, in industrial high schools, handling of feedback control and sequence control is indispensable [3]. Therefore,
to inspire interest and curiosity in students, it is considered desirable that learning involves not only classroom lectures but also
experiments. However, most of the experimental equipment forcontrol is large-scale, and also very expensive, making it difficult toperform experiments involving only a few individuals.
Accordingly, in this paper, teaching materials have been developedwith the purpose of use in classroom practice, to facilitate learning
the different operations in manual control, automatic control, andPID control through experiments utilizing robots.

2. CONTENT ON MEASUREMENT AND
CONTROL DESCRIBED IN THE
GUIDELINES FOR TEACHING
HIGH SCHOOL
In teaching classes on control, although knowledge of the content
being taught is a must, to achieve smoother and more developmental teaching, it is desirable that the teacher possesses even deeper
technical knowledge on the content taught. It is therefore necessary
to develop a curriculum for students in teacher training universities
based on curriculum guidelines. In the section on industry in thehigh school curriculum guidelines, the content related to control
and the items covered have been described as follows in “Section 24
Electronic measurement control and other topics.”

S. Imai and H. Matsui / Journal of Robotics, Networking and Artificial Life 5(3) 190–193(1) Outline of electronic measurement control.
(2) Sequence control.
(3) Feedback control.
(4) Basics of computerized control.
Moreover, with respect to incorporating the aforementionedcontent, the need to facilitate a comprehensive understanding of
measurement technology, automatic control technology, and computer technology is also mentioned. In sequence control, basics ofsequence control, instruments used in sequence control, and use ofbasic circuitry and programmable controller are covered, and theaim is to make the students conversant with knowledge and technology of sequence control. Here, the representative devices usedin sequence control such as switch, relay, and timer, along withthe types, applications, and logical elements of sensors used for
detecting physical quantities such as light, temperature, and force
are also listed. Also, the need to enable the students understand thecorresponding feature, function, characteristic, and symbols used,
and use them in practice is mentioned. In feedback control, thebasics of feedback control, control characteristics, and the use offeedback control are covered, and the aim is to make the students
conversant with knowledge and technology of feedback control.
Here, the representative feedback control applications such as process control and servo control are listed, and the need to enable
the students understand the respective overviews and use them inpractice is mentioned.

3.1. Precautions for Production
The following aspects were considered in producing the robot.
(1) Can be produced inexpensively.
(2) No special parts are used.
The reason for this is to enable building a number of such devices
inexpensively, so that they can be utilized easily in actual educational settings. Moreover, this is also easy to enable replacement ofparts as the devices may malfunction with repeated use.
Figure 2 shows the external appearance of the robot. This robot
uses parts purchased at 100 yen shops, and the total cost of parts
per robot is about 5000 yen.

3.2. Hardware
Figure 3 shows the robot circuitry used in the hardware configuration. The computer used was Arduino Uno Rev3 (Next, Arduino).
Using this computer, the input to the motor is calculated using theoperation command and information from the sensors. Arduino isused by connecting it to a personal computer. The PC displays theinput, the output results, and the various gains.

3. EDUCATIONAL ROBOT TEACHING
MATERIALS
Figure 1 shows the overall image of teaching materials using robots.
The robot can throw ping-pong balls. The robot is equipped withmotor for throwing the ping-pong ball, tachometer to measure
the speed of the motor, and distance measuring (GP2Y0E03) for
determining the distance over which the ping-pong ball is thrown.
This robot can throw the ping-pong ball to insert it into the goal bycontrolling the motor revolutions per minute (RPM) in accordancewith the distance determined by GP2Y0E03.
Figure 2 | Robot

Figure 1 | Control teaching materials robot

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Figure 3 | Circuit

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192

Moreover, as shown in Figure 4, volumes are attached to the circuitboard for adjusting the various gains. Additionally, a switch has
also been installed for switching between manual and automatic
control modes.

3.3. Software
Arduino, using its function for 10-bit resolution of analog electrical voltage input, produces a number (integer) in the range of0–1023. The output voltage is controlled by pulse width modulation (PWM). The output using 8-bit resolution specifies a number(integer) in the range of 0–255, thus changing the duty ratio. Theduty ratio is 0% when the number is 0, 50% when the number is
128 and 100% when the number is 255.
The rotor RPM is calculated using the following Eq. (1), based on
the tachometer output voltage.
e[V ] =5.0
ei (1)1024

where, e[V] is the sensor output voltage, ei is a value in the 0–1023
range. The ball is thrown by the rotor toward the goal, and thetachometer output voltage is measured 10 times as the ball isthrown at 10 cm intervals of the robot position. The relationshipbetween the tachometer voltage and the robot position is estimatedusing the least square method.

4. EXPERIENCE CONTENTS
The hands-on training is conducted using the robot. The specificeducational content of the experiments are as follows:(1) Difference between manual and automatic control.
(2) Difference between ON–OFF and PID control.
(3) How to adjust the PID gain of automatic control?
Consider the block diagram as shown in Figure 5. However, r(t) is
the target value, y(t) is the output, and e(t) is the deviation (=r(t) −e(t)) between the target value r(t) and the output value y(t). u(t) is
the input (manipulated variable).

4.1. Control Tuning
Learn that by using simple ON–OFF control, it is not possible tocontrol accurately in the sense of perfectly matching the target value.
With respect to the control result, teach the aspect that not only
the output but also the input observation are important. ON-OFF
control is expressed by the following Eq. (2).

u , e(t ) > 0u (t ) =  c(2)0, e(t ) ≤ 0
where, uc is a constant value.
Design a proportional controller and give an appropriate proportional gain Kp to observe the output. P control is expressed by thefollowing Eq. (3).
u(t) = Kpe(t)(3)In the case of stable control, steady-state deviation occurs and learns
that it becomes unstable when Kp increases.
The PI control is expressed by the following Eq. (4).
tu(t ) = K pe(t ) + K I ∫ e(t )dt (4)0where, KI is the integral gain. In this case, unlike the P control, learn
that the steady-state error can be made zero.
PID control is expressed by the following Eq. (5).
tu(t ) = K pe(t ) + K I ∫ e(t )dt + K D	 0de(t )(5)dtwhere, KD is the integral gain. At this time, the understanding of PID
control is enhanced by finding the optimal gain through trial anderror concerning the three gains. Figures 6 and 7 show the output
results of the robot. As observed in Figure 6, since gain is not properly adjusted, the response produced is oscillatory. As observed inFigure 7, with properly adjusted gain the response has improved.

Figure 5 | Block diagram

Figure 4 | Operation unit

Figure 6 | Gain unadjusted result

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193

ACKNOWLEDGMENT
The authors thank by Prof. A. Yamada from the Tokyo Gakugei
University for his valuable comments.

REFERENCES
Figure 7 | Gain adjusted result

5. CONCLUSION
In this paper, teaching materials were developed so that usefulness of measurement and control can be actually experienced. As aresult, manual and automatic control of the rotor could be realized.
It is hoped that further improvement can be realized in the future
through setting of challenges such as taking into account equipment trouble, and setting difficulty level in hands-on training.

[1] K. Asato, K. Teruya, T. Nagado, S. Tamaki, Development of magnetic levitation system for science and technology education:
magnetic levitation control by using a hall element displacement
sensor with neural network, IEEJ Trans. Ind. Appl. 136 (2016),744–752.
[2] T. Asai, K. Osuka, M. Ishikawa, M. Inoue, A motivational ­lectureusing an experimental control system to get personal experienceand its effectiveness, Trans. Soc. Instrum. Control Eng. 48 (2012),622–631.
[3] Ministry of Education, Culture, Sports, Science and Technology:
High School Study Guidelines Explained (Industrial Edition),
Jikkyo Shuppan Co., Ltd., 2010.

Authors Introduction
Dr. Shinichi Imai

Mr. Hideto Matsui
He graduated doctor course at Depart­
ment of Engineering in Hiroshima
University. He works at Department ofEducation in Tokyo Gakugei University.
His research area is about control systemdesign, educational engineering.

He graduated master course at Depart­ment of Education in Tokyo Gakugei
University. He works at National
Institute Technology. He is interested incontrol education.