Performance identification of proximity sensor for a mobile robot (tt)

Performance identification of proximity sensor for a mobile robot ࡰᏤ௲௤: ᗛమ݄!. The static performance of a proximity sensor plays an important role due to it affects the dynamic properti

ᅺγፕЎ!

Master’s Thesis Graduate Institute of Digital Mechatronic Technology

College of Engineering Chinese Culture University

ඵችᐒᏔΓҔϐௗ߈໺གᏔ܄ૈ᠘ۓ!

Performance identification of proximity sensor for a mobile robot

ࡰᏤ௲௤: ᗛమ݄!

Advisor: Professor Tsing-Tshih Tsung

ࣴ!ز!ғǺٜᚶ!

Graduate Student: Nguyen Hoai

ύ๮҇୯ 215 ԃ 12 Д!

ABSTRACT

For a control system, using the static performance of a sensor is always a milestone

of dynamic performance of the system The static performance of a proximity sensor plays an important role due to it affects the dynamic properties quality of a mobile robot and the results of dynamic identification A proximity sensor is a common sensor to search a metal guideline for a mobile robot If the signal of a proximity sensor is unstable or noisy, it gets more disturbances for a mobile robot control

In this study, the hand-made measurement system is successful developed, and 6 types of metals are measured Beside, through a detailed study of theoretical knowledge and by some empirical methods of the conveyor belt sytem, the relationship of the parameters can be determined, such as: velocity, sensing distance, dimension of material, thickness of material, and so on

Through measurement, the static and dynamic performances of a proximity sensor can be fast evaluated and analyzed, respectively The experimental results show that the signals of ferrous, non-ferrous and alloy metal tape have giant differences Simultaneously, for the dynamic measurement, the shape as the output signal depends both the type of sensor being used and thickness of material, velocity, sensing distance Determining how to rapidly and efficiently control a mobile robot therefore becomes the key point in using the measurement technique of static and dynamic performance

In the future, to exploit the effectiveness of using proximity sensors, multiple coils are arranged in a row to precisely measure the horizontal displacement of a metal target

to a tenth of a millimeter A micro-controller evaluates the damping of the different coils by the target and thereby calculates the exact position The measurement result is independent on the precision of the vertical guidance of the target

Keywords: identification of the sensor, static performance, inductive proximity sensor, mobile robot, dynamic performance

ACKNOWLEDGEMENT

First and foremost, I would like to express my deep gratitude to my master thesis advisor, Prof Tsing-Tshih Tsung I have learned many things since I became Prof Tsung’s student He spends time vary much time instructing me how to write a paper, how to search document, how to find a new idea and how to collect data

Special thanks are given to Graduate Institute Digital Mechatronic Technology, Chinese Culture University Most of my theoretical foundations are built in the Graduate Institute Digital Mechatronic Technology I also express my profound sense of reverence to Pro.Jeng-Tze Huang, who is Professor of the Graduate Institute Digital Mechatronic Technology He gave me the most sincere advice to pass the most difficult times

In addition, I also wish to express my sincere gratitude to Miss Shiu Wei-Jen, assistant of the Graduate Institute of Digital Mechatronic Technology, Chinese Culture University, for her kindness and enthusiasm of providing me the useful and quick information

I owe special thanks to my classmates and laboratory mates for their supports and encouragements Without their help, it is difficult for a foreign student like me can do anything as good as expected

I will never be able to find words adequate to express my profound gratitude to my family, for their love, supports and sacrifices Their encouragements are motivation for

me to finish this thesis

Nguyen Hoai

Jan, 18th 2015

TABLE OF CONTENTS

ABSTRACT ii

ACKNOWLEDGEMENT iii

TABLE OF CONTENTS iv

LIST OF FIGURES vi

CHAPTER 1 INTRODUCTION 1

1.1 Research Background and Motivation 1

1.2 Research Objectives 4

1.3 The structure of this Study 5

1.4 Significance of the Study 6

CHAPTER 2 LITERATURE REVIEW 7

2.1 Historical development of proximity sensor 7

2.2 Inductive proximity sensor 8

2.2.1 Detection principle of inductive proximity sensor 9

2.2.2 Analog proximity sensor 11

2.2.3 Digital proximity sensor 13

2.3 Applications of proximity sensor 15

2.3.1 Detecting dynamic motion 15

2.3.2 Touch-pads 15

2.3.3 Aviation safety 15

2.3.4 Ground proximity warning system 15

2.3.5 Air gauging 15

2.3.6 Differential systems 16

2.3.7 Speeding 16

2.3.8 Conveyor system 16

2.4 Standard detectable static of inductive proximity sensor 16

2.4.1 Sensing distance 16

2.4.2 Hysteresis 18

2.5 Dynamic models to measure performance of the proximity sensor 19

CHAPTER 3 MEASUREMENT METHOD 23

3.1 Diagram and operating principle of static measurement system 23

3.2 Diagram and operating principle of dynamic measurement system 25

CHAPTER 4 RESULT AND DISCUSSION 28

4.1 Static performance measurement of proximity sensor 28

4.1.3 99.99% Copper, 0.025 mm thickness 30

4.1.4 Aluminum, 0.1 mm thickness 31

4.1.5 Aluminum, 0.15 mm thickness 31

4.1.6 Alloy, d=0.3 (mm) 32

4.2 Dynamic performance measurement of proximity sensor 33

4.2.1 Deformation of the aluminum tape with plastic tape and without plastic tape 33

4.2.2 The output signals with analog and digital proximity sensors respectively 34

4.2.3 The relationship between the speeds of conveyor belt (v), sensing distance (h) and the shape of the output signal (peak to peak voltage and duty cycle) 36

4.2.4 The shape output signal when adding a plastic tape underneath the aluminum tape 42

CHAPTER 5 CONCLUSION AND FUTURE WORK 46

5.1 Conclusion 46

5.2 Future work 47

REFERENCE 48

LIST OF FIGURES

Figure 1 Scheme of mobile robot system 1

Figure 2 Typical inductive proximity sensor configuration 2

Figure 3 Performance identification for mobile robot 3

Figure 4 The first proximity sensor (source: http://www.controlengeurope.com/article/20839/Fifty-years-old the-proximity-switch.aspx) 7

Figure 5 Proximity parameters 9

Figure 6 Proximity sensor configuration 10

Figure 7 Sensor's electromagnetic fields 11

Figure 8 Inductive analog sensor 12

Figure 9 Current and Voltage output of proximity analog sensor 12

Figure 10 Measurement range of proximity analog sensor 13

Figure 11 Voltage output of digital proximity sensor 14

Figure 12 Electronic output circuits of digital proximity sensor 14

Figure 13 Sensing distance definition 17

Figure 14 Hysteresis 18

Figure 15 Metal detector in conveyor belt system 19

Figure 16 Metal detector in gear 20

Figure 17 Detecting whether an object exists in a defined position 20

Figure 18 Positioning of an object 21

Figure 19 Counting the number of parts 21

Figure 20 Determining the rotational speed 22

Figure 21 Determining the linear speed 22

Figure 22 A testing setup of measurement system 23

Figure 23 Inductive proximity sensor current versus displacement 24

Figure 24 Diagram of measurement system with digital proximity sensor 25

Figure 25 Diagram of measurement system with analog proximity sensor 26

Figure 26 Relationship of sensing distance and thickness of 301 stainless steel 28

Figure 27 Relationship of sensing distance and thickness of 99.99% copper, 0.05-0.4 mm thickness 29

Figure 28 Relationship of sensing distance and thickness of 99.99% copper, 0.025-0.2 mm thickness 30

Figure 29 Relationship of sensing distance and thickness of aluminum, 0.1-0.8 mm thickness 31

Figure 30 Relationship of sensing distance and thickness of aluminum, 0.15-1.2 mm thickness 31 Figure 31 Relationship of sensing distance and thickness of alloy, 0.3-2.4 mm thickness

Figure 33 Deformation of aluminum tape with a normal plastic tape 33

Figure 34 Deformation of aluminum tmation of aluminum tape with a special plastic tape 33

Figure 35 Digital output signals with digital proximity sensor 34

Figure 36 Analog output signals with analog proximity sensor 35

Figure 37 The shape of the output signal corresponding to the speed 1.3 m/s 36

Figure 38 The shape of the output signal corresponding to the speed 3.4 m/s 37

Figure 39 The relationship between v(m/s) and Vpp (mV) 38

Figure 40 The relationship between v (m/s) and D (%) 38

Figure 41 The shape of the output signal corresponding to the sensing distance 1.5 mm 39

Figure 42 The shape of the output signal corresponding to the sensing distance 3.5 mm 40

Figure 43 The relationship between h (mm) and Vpp (mV) 41

Figure 44 The relationship between h (mm) and D (%) 41

Figure 45 The shape of the output signal when adding 1 plastic tape underneath the aluminum tape (v=const) 42

Figure 46 The shape of the output signal when adding 2 plastic tape underneath the aluminum tape (v=const) 43

Figure 47 The shape of the output signal when changing the thickness of aluminum tape (h=const) 44

Figure 48 The shape of the output signal when changing the thickness of aluminum tape (v=const) 45