a wireless camera supervision robot (csr-bot) for

A WIRELESS CAMERA SUPERVISION ROBOT (CSR-BOT) FOR

THE CYLINDRICAL PIPES AND CABLES SURFACES OBSERVATION

AHMAD HANIFF BIN MUHAMMAD MUHYIDDIN

A project report submitted in partial

fulfillment of the requirement for the award of the

Degree of Master of Electrical Engineering

Faculty of Electrical and Electronic Engineering

Universiti Tun Hussien Onn Malaysia

JULY 2014

ABSTRACT

Nowadays, the use of robots as an observer has been used for a variety of sectors.

However, the use of robots to monitor the condition of high voltage cable is not yet

widespread. As a result, the project aims to design and create a robot for monitoring a

cable condition. In addition, the project will aid the use of manpower as cable condition

monitor. There are various disadvantages of using manpower such as not monitoring the

situation accurately and they may face with electromagnetic radiation which can

minimize their health risk for a long term. This project is to develop a semi-automatic

mobile robot that can move along through the overhead transmission line cable or any

cylindrical pipes surfaces. The problem can be improved by using the Camera

Supervision Robot (CSR-BOT), which can observe the cable from three different angles.

This is because the CSR-BOT body is equipped with three webcam cameras. This is to

ensure the handler could inspect the cable condition accurately. The live preview from

the webcam camera during the inspection can be viewed, captured (image) and recorded

(video) directly from laptop by using a simple Graphical User Interface (GUI) called

“GUI-Interface for CSR-BOT” program. This program is able to record video in high

quality AVI format while the images captured will be stored in the PNG file extension.

Monitoring system of the robot is able to see the condition of the cables if there are any

scratches, dust and rust. If there is any problem at the cable, it may affect performance of

the electrical current flow through the conductors. CSR-BOT is also capable of

withstanding the vibration resistance when tested horizontally or vertically. Based on the

data taken, cable maintenance can be easily done because the distance of the damage

cable can precisely know by the technician. In addition, the CSR-BOT can be used on

cable size from 1cm to 2.5cm and can monitor the condition of the cables from three

different angles of 0 ° -120 °, 120 ° -240 ° and 240 ° -360 °.

ABSTRAK

Pada masa kini, penggunaan robot sebagai pemantau sudah lama digunakan

untuk pelbagai sector. Akan tetapi penggunaan robot untuk memantau kondisi kabel

bervoltan tinggi adalah masih belum meluas. Disebabkan itu, projek ini bertujuan untuk

mereka dan mencipta sebuah robot pemantau kondisi kabel. Selain itu, projek ini dapat

membantu penggunaan tenaga manusia sebagai pemantau keadaan kabel. Penggunaan

tenaga manusia sebelum ini terdapat pelbagai kekurangan seperti tidak memantau

keadaan kabel secara jitu dan mereke mungkin akan berhadapan dengan radiasi

electromagnet yang boleh memberi kesan kepada kesihatan mereka untuk jangka masa

yang panjang. Tujuan projek ini adalah untuk membangunkan sebuah robot mudah alih

separa automatik yang boleh bergerak melalui kabel bervoltan tinggi atau mana-mana

permukaan paip silinder. Keadaan ini berbeza dengan penggunaan Camera Supervision

Robot (CSR-BOT) yang boleh memerhati keadaan kabel dari tiga sudut berbeza. Ini

kerana terdapat tiga buah kamera web pada CSR-BOT. Selain itu juga, CSR-BOT dapat

merakam video, menangkap imej dan memberikan paparan terus menerusi “GUI-

Interface for CSR-BOT” pada komputer riba pemeriksa kabel. CSR-BOT ini mampu

merakam video dalam format AVI yang berkualiti tinggi. Manakala imej yang diambil

akan disimpan dalam format PNG. Pemantauan daripada robot ini dapat melihat kondisi

pada kabel jika terdapat calar, habuk dan karat. CSR-BOT juga mampu menahan

rintangan apabila diuji dengan gegaran secara melintang atau menegak. Sekiranya

kondisi kabel bermasalah, ia akan menjejaskan prestasi pengaliran arus elektrik.

Berdasarkan daripada data yang diambil, penyelenggaraan kabel dapat dilakukan dengan

mudah oleh juruteknik kerana jarak kerosakan dapat diketahui dengan tepat. Disamping

itu, CSR-BOT boleh digunakan pada kabel dari saiz 1cm hingga 2.5cm dan dapat

memantau kondisi kabel dari tiga sudut berbeza iaitu 0°-120°, 120°-240° dan 240°-360°.

viii

TABLE OF CONTENTS

DESCRIPTION PAGE

TITLE i

DECLARATION ii

DEDICATION iv

ACKNOWLEDGEMENT v

ABSTRACT vi

ABSTRAK vii

CONTENTS viii

LIST OF TABLES xii

LIST OF FIGURES xiii

LIST OF ABBREVIATIONS xix

LIST OF APPENDIXES xx

CHAPTER 1 INTRODUCTION 1

1.1 Introduction 1

1.2 Background of the study 1

1.3 Problem Statement 3

1.4 Objective of the study 4

1.5 Scope of the Project 5

1.6 Thesis Structure 7

CHAPTER 2 LITERATURE REVIEW 8

2.1 Introduction 8

2.2 Overhead Line Tower Types 8

2.3 Conductor for Overhead power lines 11

ix

2.4 Swing Conductors 13

2.5 Conductor Vibration 16

2.6 Conductor Corrosion Damage 18

2.7 Previous Research 20

CHAPTER 3 METHODOLOGY 26

3.1 Introduction 26

3.2 Membrane materials 26

3.3 Development of the CSR-BOT 28

3.4 Step of Mechanical Design for a CSR-BOT 28

3.4.1 The Structure Design for the CSR-BOT 29

3.4.2 The Details Specification of the CSR-BOT 32

3.4.3 Type of motor used for the CSR-BOT 33

3.5 System Architecture 35

3.6 Electrical Control System of CSR-BOT 38

3.6.1 Electrical Schematic Diagram for 38

Remote control

3.6.2 Electrical Schematic Diagram for Robot 42

3.7 Software development for CSR-BOT 46

3.7.1 Setup Address for Xbee Module by using 46

X-CTU software

3.7.2 Programming for CSR-BOT 52

I. Programming for Remote Control 55

by using Arduino IDE software

II. Programming for Robot by using 61

Arduino IDE software

x

3.7.3 GUI- Interface for CSR-BOT 64

I. Programming for Recording and 67

Capturing Image by using Matlab

Software

II. Programming for Image Viewer 72

by using Matlab Software.

CHAPTER 4 RESULT AND DISCUSSION 77

4.1 Introduction 77

4.2 Results for Performance of the CSR-BOT 77

4.2.1 Result for Remote Control Functionality 79

4.2.2 Result for the CSR-BOT functionality 83

4.3 Results of Effectiveness GUI-Interface for 86

the CSR-BOT

4.3.1 Result for GUI-Interface for the CSR-BOT 86

functionality

4.3.2 Result for Image Viewer for the CSR-BOT 92

4.4 Analysis for the CSR-BOT 98

4.4.1 Weight of the CSR-BOT 98

4.4.2 Torque calculation 101

4.4.3 Range test 104

4.4.4 Transmitting and Receiving signal 107

waveform

4.4.5 Distance calculation and measurement 115

4.4.6 Distance Verification 116

4.4.7 Flexibility with other conductor size 118

4.4.8 Vibration testing 121

4.4.9 Sagging Testing 126

4.4.10 Coverage Observation 130

4.4.11 Image Capture 135

xi

4.4.12 Video Recorded 137

I. Video Test for the PVC Pipe 137

II. Video Test for the Nylon Rope 139

CHAPTER 5 CONCLUSION 141

5.1 Conclusion 141

5.1.1 Structure Design for the CSR-BOT 141

5.1.2 Movement Capability of the 142

CSR-BOT

5.1.3 Testing of Prototypes 142

5.2 Recommendation for the CSR-BOT 146

Improvement

REFERENCES 148

APPENDICES 150

xii

LIST OF TABLES

2.1 AAAC type conductor bundle for National Grid Company’s 11

overhead line tower

2.2 Summary of previous research about mobile robot 20

2.3 Comparison between flying design robot, gripping design 24

robot and wheel design robot

2.4 Advantages and disadvantages of types of gripper 25

3.1 The Details and Descriptions of CSR-BOT 32

3.2 Resistance value of six wires stepper motor 35

3.3 The address for each Xbee module 50

4.1 Table of device weight 99

4.2 Table of weight of each conductor cable according to type 100

and size

4.3 The CSR-BOT range testing 105

4.4 Table of measurement value result of Channel 1 and 110

Channel 2 for remote control

4.5 Table of measurement value result of Channel 1 and 114

Channel 2 for robot

xiii

LIST OF FIGURES

1.1 An overhead transmission line of rated voltage level 2

1.2 A manually inspection for overhead transmission line done 2

by lineman

2.1 Typical tower outlines 9

2.2 Corona ring attached on the insulator fittings 9

2.3 Vibration damper- type Stock Bridge damper 10

2.4 Example of the Maximum sag is measured at maximum load 12

on hot day

2.5 Determination of swing angle on the basic of relative 14

horizontal (wind) and vertical (system weight forces)

2.6 Illustration Method in determining the wind loading on 15

conductor

2.7 Aeolian vibration on cable or circular cylinder 16

2.8 Damage caused by Aeolian vibration 17

2.9 Effect of corrosion occurred in aluminum conductors 18

2.10 Minimum life expectancy of core greased zebra 19

3.1 Research Framework 27

3.2 The steps for designing a CSR-BOT 28

3.3 The 3D model of the CSR-BOT 29

3.4 Top view of CSR-BOT (The center of gravity is designed to 30

be at the center of the pulley)

3.5 Front view of the CSR-BOT 31

3.6 Side view of the CSR-BOT 31

3.7 Unipolar stepper motor 33

3.8 Specification of unipolar stepper motor 33

3.9 Six wires stepper motor wiring 34

3.10 Five wires stepper motor wiring 34

xiv

3.11 CSR-BOT system operation 37

3.12 Schematic diagram for remote control of the CSR-BOT 39

3.13 Remote Control Circuit board attachment according to 40

their layers sequence

3.14 Side view of circuit board (Remote) attachment according 41

to their layers sequence

3.15 Overall complete circuit attachment for remote control 41

3.16 Motor driver used for the robot 42

3.17 Schematic diagram for the robot 43

3.18 Circuit board attachment according to their layers sequence 44

3.19 Side view of circuit board for robot and its attachment 45

according to their layers sequence

3.20 Complete circuit attachment for the CSR-BOT 45

3.21 Connect both Xbee module to PC / Laptop 46

3.22 Windows notification after successfully installing a device 47

3.23 Open the X-CTU software 47

3.24 Initialize the port for each Xbee Wireless module 48

3.25 Result of successful for each Xbee module are working fine 49

3.26 Setup address for each Xbee Wireless 50

3.27 Sucessful result of Xbee module could transmitt and revieve 51

the signal between each other

3.28 Remote control programming procedures 53

3.29 CSR-BOT programming procedures 54

3.30 Pin configuration for the Xbee 1 module 55

3.31 Source code for Xbee 1 module to send “W” signal 56

3.32 Source code for Xbee 1 module to send “S” signal 56

3.33 Initialize pin for joystick 57

3.34 Result of on getting the integer values 58

3.35 Source code for joystick 58

xv

3.36 Initialize pin for LCD display 59

3.37 Source code for LCD display to write the 59

“Hello User!!..” phrase

3.38 Source code for LCD display to write the welcome note 60

Phrase

3.39 Source code for LCD display to write the credit phrase 60

3.40 Source code if Xbee 2 module receiveing “S” signal 61

3.41 Source code if Xbee 2 module receiveing “W” signal 61

3.42 Initialize pin for the unipolar stepper motor 62

3.43 Source code for stepper motor to perform backward movement 63

3.44 Source code for stepper motor to perform forward movement 63

3.45 Recording and Image capturing programming procedures 65

for CSR-BOT

3.46 Image Viewer programming procedures for CSR-BOT 66

3.47 GUI-Interface design layout by using Matlab 2011b software 67

3.48 Source code for preview webcam camera in YCbCr Mode 68

3.49 Source code for preview webcam camera in RGB Mode 69

3.50 Source code for preview webcam camera in Gray Scale Mode 69

3.51 Source code for recording a video from webcam camera 70

3.52 Source code for capturing an image from webcam camera 71

3.53 Image viewer design layout by using Matlab 2011b software 72

3.54 Source code for loading an image 73

3.55 Source code for flip the image 180° 74

3.56 Source code for flip the image in vertical 74

3.57 Source code for flip the image in horizontal 74

3.58 Source code convert the image in negative color mode 75

3.59 Source code convert the image into gray scale mode 75

3.60 Source code for increasing the brightness of the image 76

3.61 Source code for viewing the histogram graph of the image 76

4.1 Structure view of the CSR-BOT 78

4.2 LCD display show a “Hello User!!..” phrase 80

4.3 LCD display show a “Welcome To Cable Inspection

Robot” phrase 80

4.4 LCD display show a “Creator: Ahmad Haniff” phrase 81

xvi

4.5 LCD display show a “Supervisor: Dr. Ramdon” phrase 81

4.6 LCD display show a “Forward” phrase and distance traveled 82

by the robot

4.7 LCD display show a “Backward” phrase and the decrement 82

of distance traveled by the robot

4.8 The CSR-BOT as hanging on the rope 83

4.9 The camera position attached to the CSR-BOT membrane 84

4.10 Operation button system for the CSR-BOT 85

4.11 All three webcam cameras preview in YCbCr camera mode 87

4.12 All three webcam cameras preview in RGB mode 88

4.13 All three webcam cameras preview in Gray scale mode 88

4.14 Warning dialog appears after capturing the image 89

4.15 The video recorded is save in .Avi file extension 89

4.16 The image captured is save in .Png file extension 90

4.17 The details about the GUI-Interface for the CSR-BOT program 90

4.18 Saving data dialog appears before exit the program 91

4.19 Closing dialog appears before exit the program 91

4.20 Load a selected image into the program 93

4.21 180° Rotation angle ability of the image by the Image 93

Viewer program

4.22 Ability to flip the image horizontally by the Image 94

Viewer program

4.23 Ability to flip the image vertically by the Image Viewer program 94

4.24 Ability to apply Negative color mode to the image by the 95

Image Viewer program

4.25 Ability to apply gray scale color mode to the image by the 95


4.26 Example of decreasing the brightness of the image by the 96


4.27 Example of increasing the brightness of the image by the 96


4.28 Ability to preview the histogram graph of the image by the 97


xvii

4.29 Weight of the remote control 98

4.30 Weight of the CSR-BOT 99

4.31 Getting the holding torque value from the motor spec 101

4.32 The rope inclined at 10° angle 102

4.33 The graph of Efficiency (%) vs. Distance (m) for CSR-BOT 106

4.34 Setup connection for channel 1 and channel 2 107

4.35 Measurement value for Channel 2 (TX-pin of Xbee 1 module)

waveform for remote control (part 1) 108

4.36 Measurement value for Channel 2 (TX-pin of Xbee 1 module)

waveform for remote control (part 2) 109

4.37 Close-up of transmitting signal waveform for remote control

(increasing the time base setting scale up to 500µs per division) 109

4.38 Measurement value for Channel 1 (RX-pin) waveform for

remote control 110

4.39 Measurement value for Channel 1 (RX-pin of Xbee 2 module)

waveform for robot (part 1) 112

4.40 Measurement value for Channel 1 (RX-pin of Xbee 2 module)

waveform for robot (part 2) 112

4.41 Close-up of receiving signal waveform for robot

(increasing the time base setting scale up to 500µs per division) 113

4.42 Measurement value for Channel 2 (TX-pin) waveform for robot 113

4.43 Starting point for the robot moving forward 117

4.44 Comparing the distance measurement result using a tape measure 117

4.45 The details about U-slope pulley spec and its attachment 118

4.46 U-slope pulley tested using Nylon rope 119

4.47 U-slope pulley tested using PVC pipe 120

4.48 Sequence image for vibration in vertical condition testing part 1

(blue line represents the reference line) 122

4.49 Sequence image for vibration in vertical condition testing part 2 123

4.50 Sequence image for vibration in horizontal condition testing

(blue line represents the reference line) 124

4.51 Setup preparation for the test conductor cable sagging by 5 cm 126

4.52 Sequence of CSR-BOT movement on cable sagging by 5 cm 127

4.53 Preparation for the test conductor cable sagging by 12 cm 128

xviii

4.54 Sequence of CSR-BOT movement on cable sagging by 12 cm 129

4.55 Angular view of each webcam cameras 130

4.56 Example damage on PVC pipe 131

4.57 Live preview for PVC pipe in YCbCr mode 132

4.58 Live preview for PVC pipe in RGB mode 133

4.59 Live preview for PVC pipe in Gray scale mode 134

4.60 Image capture from each webcam camera for PVC pipe test 135

4.61 Image capture from each webcam camera for Nylon rope test

(outdoor test) 135

4.62 Image capture from each webcam camera for Nylon rope

test (indoor test) 136

4.63 Video recorded from Webcam camera 1 for PVC pipe 137



4.66 Video recorded from Webcam camera 1 for Nylon rope 139



xix

LIST OF ABBREVIATIONS

qz Dynamic wind pressure

Ac Wind loading area of the conductor

Ai Wind loading area of the insulator

Wc Total weight of the conductor

Wi Total weight of the insulator

Cc The drag coefficient factor

dcr The conductor diameter in meters

ncr The number of conductor bundles

L1, L2 Span of line erected on three towers in meter

Ω The wind direction angle in degree with respect to the span

line

ai Total area seen in side view

Gi The drag factor

fs Vortex shedding frequency (Hz)

S Strouhal number 0.185÷2

V Wind speed (m/s-1

)

d Diameter cable (m)

xx

LIST OF APPENDICES

APPENDIX TITLE PAGES

A Dimension of the CSR-BOT 151

B Data sheet for the unipolar stepper motor 152

C Coding for remote control of the CSR-BOT 153

D Coding for the CSR-BOT 159

E Coding for GUI-Interface for the CSR-BOT 162

F Coding for Image Viewer 179

1

CHAPTER 1

INTRODUCTION

1.1 Introduction

This chapter discusses the background of the research problem. It generally describes

about methods currently used by the electricity provider company to monitor the high

voltage cable. This chapter also highlights the problem statement based on the

background provided as well as the objectives, limitations and significance of the study.

1.2 Background of the Study

In this modern day, robot has replaced a lot of human job that may harmful to human

life. There are common semi-automatic machine used by human to perform a difficult

work where a person still needed to supervise the machine and decide about the task [1].

However, the use of robot to monitoring the condition of high voltage cable at the

overhead transmission line such as shown in Figure 1.1 is not yet widespread.

Over several years, the overhead transmission line cable inspection has been

done manually by experienced and well trained workers as shown in Figure 1.2.

Recently, scientist and researcher are work together to plan-out a new method to

substitute a worker with a robot to do the transmission line cable inspection. This

method may save a lot of expenses from the electricity provider company and could

reduce a risk of human life.

2

Figure 1.1: An overhead transmission line of rated voltage level [2]

The purpose of this inspection is done to monitor if there are any scratches, dust and rust

of the cable. These problems may affect performance of the electrical current flow

through the conductors (as detailing discusses in problem statement).

The disadvantage of using manpower is they may not monitor the situation

accurately. In enhance the safeness of human life risk and improving the monitoring

method, a wireless Camera Supervision Robot (CSR-BOT) for the cylindrical pipes and

cables surfaces observation is purposed. This robot may improve on the quality of visual

inspection practices commonly used this day and these technologies are targeted to

include a GUI interface for collecting data from the wireless camera.

Figure 1.2: A manually inspection for overhead transmission line done by linesman [2]

3

This project is to develop a semi-automatic mobile robot that can move along through

the overhead transmission line cable. The Camera Supervision Robot (CSR-BOT) is

equipped with wireless camera supervision. This is to ensure that the handler could

inspect the cable condition of the transmission line cable.

The data from wireless camera can be viewed directly from the computer. With a

simple Graphical User Interface (GUI), the handler could record a video and captured

the image during the inspection. Based on the data taken, cable maintenance can be

easily done by the technician.

The important aspect should be considered during designing this robot is noise

and interference produce when corona is discharging. This problem is occurred when if

there are any scratches on the transmission line cable. During corona discharges, pulse

of voltage and current will be created on the transmission line. The radio frequency

noise also will be existed and it may interference the radio and television reception.

Researcher found that sometimes the radio and television interference is not considered

to be significantly influenced by transmission line coronas, it may cause by other things

[3].

This aspect may cause a problem especially when handler wants to receive a data

from wireless camera to a portable computer. In solving this problem, a proper shielding

of the robot unit is essential in order to avoid noise problems receive from surrounding

area.

1.3 Problem Statement

During a hot sunny season, transmission line can easily get scratch, dust and water may

also affect the conductor's electrical performance [4]. This situation may produce

creation of coronas. A corona will occur if there are any energy losses along the

transmission line. The inspections for the transmission line are needed to prevent a

variety of phenomenon.

After the construction is complete, all the transmission line need to be inspected

before energizing the line.

4

Linesman will climb each structure of the transmission line to check the

following conditions [5]:

1. Conductor condition

2. Conductor sag and clearance to ground, trees, and structures.

3. Insulator conditions.

4. Line hardware for roughness and tightness. Excess inhibitor found should be

removed from conductors to prevent corona discharges.

5. Structure vibration and alignment.

6. Ground-wire connections and conditions.

7. Ground resistance at each structure.

8. Structure footings for washouts or damage.

9. Obstruction light operations for aircraft warning.

Once a year, the inspection for overhead high voltage transmission line needs

to be done. For a decade, most of the leading Electricity Provider Company in the world

has done an inspection for power transmission line manually. Several Workers (lineman)

are employed to check the condition of the transmission line by on foot. But in some

situation, workers will face a difficulty for travelling due to mountainous surface and

wild animal attacks [6].

Sometimes, helicopter will be used to move one workers from one

transmission line to others transmission line. This method is quite efficient and quicker.

Unfortunately, this mission is quite costly and dangerous especially during a windy

season. Another method is worker will using telescope to observe it from the ground [6].

Lineman may face with electromagnetic radiation which can minimize their

health risk for a long term. Exposing to the AC fields too much can cause non-thermal

cell damage or weaken the immune system. IEEE has set the safe exposure limit for ELF

AC from power lines which may leads to cell damage at 100mW/cm2 [7].

A new method need to be planned-out to ensure the accuracy of inspection for

overhead high voltage transmission line and can reduce a risk of human life.

5

1.4 Objective of the Study

The aim of this research is to inspect the cable and insulator condition for the overhead

high voltage transmission line. This system application should improving nowadays

inspection method that applied by the energy provider company. To achieve these aims,

the main objective of this research is to design and access an inspection robot with

wireless camera supervision through the capability of GUI interface.

The measurable objectives of the project are:

i. To develop and design mechanical robot for inspecting a high voltage cable.

ii. To monitor the high voltage cable by using mechanical robot and three

webcam camera.

iii. To test the performance of the Camera Supervision Robot (CSR-BOT).

1.5 Scope of the Project

The project is focus on to test the performance of the inspection robot with wireless

camera supervision.

The scopes of the project are:

i. Design the robot using SolidWork premium 2013 software. The joystick is used

to navigate the movement of the robot. The robot is design to be less than 5kg.

ii. The robot will be monitor using three webcam cameras. Model of the camera is

Sensonic 6100.

iii. The robot will observe the cable condition in GUI-Interface program created in

Matlab 2011b software. The output result only will be save in image capture and

video recorded.

iv. The experiment been carried out to test the performance of the CSR-BOT as

follows:

a) The robot is tested in range of 0 to 30 meter.

b) The robot will be tested on the Nylon rope (diameter size: 1 cm) and PVC

pipe (diameter size: 2 cm).

6

c) The robot is only been tested in a horizontal alignment of the subject

(Nylon rope and PVC pipe).

d) There is no obstacle along the testing subject during the experiment.

e) The robot will be tested in two situations it is indoor and outdoor.

1.6 Thesis Structure

This chapter has highlighted the common methods currently used by the

electricity provider company to monitor the high voltage cable and the difficulties

encountered by their technician during the inspection. The chapter also explains

summary about the significance of the inspection for the high voltage conductor cables

and the purpose used of the Camera Supervision Robot (CSR-BOT) to assist in

monitoring the conductor cables. The remainder of the thesis is structured as follows:

Chapter 2 outlines the literature related to the high voltage transmission line.

The finding is focusing on the cable conductor’s physical aspect. This chapter also

discusses some examples of design concept from the previous research that can be used

to develop the CSR-BOT.

In Chapter 3 describing the research method for hardware and programming

part used for this project. Most of the contents is discussing about method on developing

the CSR-BOT. The method for developing the CSR-BOT is divided in three phase

which is mechanical part, electronic part and software part. Each of these part details are

covered in this chapter.

Chapter 4 presents some analysis that has been carried out to test the

performance of the robot and the GUI-Interface program. Several experiments have been

done to test out the performance of the robot such as movement test, range test, tested on

different type of material (other than conductor cable), distance verification, vibration

test and sagging test. In the GUI-Interface for CSR-BOT program part, the efficiency of

this software to captured, recorded and save the file during the live view is been test out.

All of the result and findings from the test were reported in this chapter.

7

Chapter 5 draws a conclusion and makes recommendation for future works.

This chapter concludes the research finding in development of a wireless Camera

Supervision Robot (CSR-BOT) for the cylindrical pipes and cables surfaces observation.

The chapter also discusses any possible suggestions for the CSR-BOT and the GUI-

Interface program for improvement.

8

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

This chapter reviews the literature related to the high voltage transmission line. This

chapter also looks into the related literature about mobile robot. A literature review is a

stepping stone for current research. Any relevant ideas related to the research will help

to provide better understanding towards achieving the improvement of current study.

2.2 Overhead Line Tower Types

In designing the overhead line tower, designer should consider about human safety

aspects first before precede with their design. For designing the overhead line tower,

there are many criteria should be concern about such as structural analysis, electrical

clearance analysis, insulator design and effect of the conductor movement due to windy

condition. The structure of the overhead line tower is more related to the concept of

voltages and current uprating.

Steel lattice material is commonly chosen in making the overhead line tower.

Wood or light steel is totally impractical material to be used in designing the tower

because at the higher voltage levels it need to deal with high wind loads and ice loads

during the winter season. In Figure 2.1, shows some examples of typical tower for single

and double circuit configuration with single and double earth wires.

9

Figure 2.1: Typical tower outlines [8]

The applications of the safety devices are crucial in preventing any stress when

there are any line fault occurrences. There are a few device used by the National Grid

Company (NGC) to overcome this problem such as corona ring. Corona ring main

function is to eliminate or reduce the occurrence of corona on the insulator fittings.

Figure 2.2 shows how corona ring been attached on the insulator fittings.

Figure 2.2: Corona ring attached on the insulator fittings [9].

Corona ring

10

Stock Bridge damper are used to absorb an Aeolian vibration and spacers is used

to limit the sub-span vibration that occur on the conductor. When a vibrations from the

main cable were passed down through the clamp and into the shorter damper, or

"messenger", cable. This would flex and cause the symmetrically-placed concrete blocks

at its ends to oscillate [10]. Stockbridge dampers is very economical and easy to install,

it is widely been used in nowadays industry. Figure 2.3 shows a model of vibration

damper type Stock Bridge damper.

Figure 2.3: Vibration damper- type Stock Bridge damper [11]:

1. Damper clamp

2. Conductor

3. Messenger cable

4. Damper weight

11

2.3 Conductor for Overhead power lines

In years 1950’s to 1960’s, the 275kV line typically used the 175mm2 twin Aluminum

Conductor Steel Reinforced (ACSR) ‘Lynx’ type of cable. While for 400mm2 ACSR

‘Zebra’ type are used for 400kV. The ASCR cables have 50°C of thermal rating. The

ASCR is heavier than the All Aluminum Alloy Conductor (AAAC) type conductor

especially with the similar equivalent diameter size of the conductor. After a few years

using these types of conductor, the ACSR cause a problem for the NGC. This type of

cable could corrosion due to time changing and will increased the cost for maintenance

in terms of detecting the occurrence of corrosion on the lines. The NGC also need to use

a high amount of grease to prevent it.

In 1990’s, All Aluminum Alloy Conductor (AAAC) has been introduced and it

may exceed a higher thermal rating up to 75°C. This cable shows to have a lower

resistance value, lighter and undergo less sag at ambient temperature. The AAAC cable

type is totally better than ACSR cable. In Table 2.1 shows an AAAC type conductor

bundle for National Grid Company’s overhead line tower [12].

Table 2.1: AAAC type conductor bundle for National Grid Company’s overhead line

tower

System

Voltage

Tower

Type Conductor System

Nominal Rated

Temperature (°C)

275 L3 1 x 700mm

2 AAAC ‘Araucaris’

2 x 300mm2 AAAC ‘Upas’

50

50

400 L24 1 x 500mm

2 AAAC ‘Rubus’

2 x 570mm2 AAAC ‘Sorbus’

75

75

12

During the unloaded condition (no current in the lines), the conductor is a result

of elastic elongation depend on the conductor’s elasticity, weight and tension.

Everyday sag is the sag develops during the installation of lines and it is occurred

under the conditions that the overhead lines experiences for most of it life time.

Everyday sag augmented by thermal elongation due to the increased temperature [13].

Loaded condition is the sag of the conductor bundle affected by joule heating from the

current. Sometimes, it’s been affected by both atmospheric temperature and solar

radiation [11].

The maximum electrical loading sag is the maximum operating conductor

temperature contributes to the maximum allowable sag clearance before the minimum

clearance to the ground level is reached. This condition also defined the maximum

continuous current capacity of the conductor itself. Figure 2.4 shows an example of the

maximum sag is measured at maximum load on hot day.

Figure 2.4: Example of the Maximum sag is measured at maximum load on hot day [14].

13

2.4 Swing Conductors

The electrical high voltage transmission line tower is a tall structure. Under the windy

condition it may cause a problem for transmission line. The wind speed are tends to

increase with the altitudes. During the high wind speed, it will cause a vibration in the

conductor system. This will cause the cable to move closer to or away from the tower

body.

Due to this swinging conductor’s problem, the displacement of live conductors

and insulators towards the tower body will reduce the clearance. This will increase the

risk of electrical flash over, while movement away from the tower body may cause

infringement of the shielding angle convergence and expose lines to direct lightning

strike.

In UK, if a swing angle is up to 10°, it must not lead any infringement of any

stated clearance. In every high winds that lead to a large swing angle condition (35°

based) the clearance only required to be sufficient to withstand the power frequency

voltage [15].

Calculating for the movement of conductors and insulator towards and overhead

line tower has been produce by CIGRE working Group 2.026 [16]. The equation below

effectively derives the swing angle on the basis of relative horizontal (wind) and vertical

(system weight) forces. The equations are used to calculate the swing angle based on

this force and the countering forces of the conductor or insulator weight. Figure 2.5

shows a determination of swing angle on the basic of relative horizontal (wind) and

vertical (system weight forces). Figure 2.6 shows an illustration method in determining

the wind loading on conductor.

(2.1)

qz = Dynamic wind pressure

Ac = Wind loading area of the conductor

Ai = Wind loading area of the insulator

14

Wc = Total weight of the conductor

Wi = Total weight of the insulator

Figure 2.5: Determination of swing angle on the basic of relative horizontal (wind) and

vertical (system weight forces)

Wind loading area of conductor bundle, Ac :

(2.2)

Cc = the drag coefficient factor

dcr= the conductor diameter in meters

ncr = the number of conductor bundles

L1, L2 = span of line erected on three towers in meter

Ω = the wind direction angle in degree with respect to the

span line

ø

Sing angle

Resultant Load

Wind load of conductor

and insulator

Weight of conductors

and insulators

15

Span of ( L1 and L2 ) correction factor, k:

Unit m

2 (2.3)

Total wind loading area of the insulator, Ai :

(2.4)

ai = total area seen in side view

Gi = the drag factor

Figure 2.6: Illustration Method in determining the wind loading on

conductor

Tower 3 Tower 2 Tower 1

L2/2 L1/2

L2 L1

Direction of wind

action

Ωa

16

2.5 Conductor Vibration

There are three types of vibration occur in the conductor bundle, it is whole span

galloping, Aeolian vibration and Sub-span vibration.

a) Whole Span galloping

The whole span galloping occurs when a whole span oscillates vertically with

sufficient amplitude to flash over or even clash with adjacent phase conductor [16]. This

type of movement is usually associated with the formation of thin ice on the conductor

and usually takes place in strong winds from 5 to 15ms-1

. The frequency of the vibration

is ranging from a 0.1 Hz to 1 Hz [11]. The amplitude size is usually from a few

centimeters to 12m [11]. The effect of the whole span galloping is it can lead to short

circuit and high acing current that produce could cause damage or complete melting of

the conductor itself.

b) Aeolian vibration (Vortex shedding)

This vibration occurs mostly in the light wind, at speeds lower than 15ms-1

[17]. The

vertical magnitude of this vibration is very small (±15mm). The oscillation frequency

ranging is between 4Hz to 70Hz [18].To overcome this problem, a Stock Bridge Damper

is used to reduce the magnitude of this vibration. This vibration can cause loosen the

cross-arm nuts. The Vortex shedding phenomenon I characterized by a frequency fs,

depending on the dimension, wind speed and a constant (S) depending on the shape [19].

Figure 2.7 shows an Aeolian vibration on cable or circular cylinder. Figure 2.8 show a

damage caused by Aeolian vibration.

Figure 2.7: Aeolian vibration on cable or circular cylinder [19].

17

(2.5)

fs = Vortex shedding frequency (Hz)

S = Strouhal number 0.185÷2

V = Wind speed (m/s-1

)

d = diameter cable (m)

Figure 2.8: Damage caused by Aeolian vibration [20]

c) Sub-span oscillation

The sub-span oscillation is also known as wake induced vibration. It can be occurs

only on bundles with at least one couple of sub-conductors with one in the wake of the

other. This type of vibration occurs for medium to high wind speed (V> 10m/s-1

) and it

is not as common as Aeolian vibration. The amplitude of the vibration is in lower

frequency (0.7÷2 Hz). This type of vibration is depending on the spacing between the

conductor bundles. The magnitude of vibration can be increased the number of spacer on

the line conductor. The effect of this vibration can cause fatigue damage to the spacer or

to the insulator fittings [15].

18

2.6 Conductor Corrosion Damage

The transmission line conductor is the most expensive component of Electrical High

Voltage lines however they are susceptible to ageing. One of the main factors that

limiting the conductor life time is unavoidable wind (Aeolian vibration).

The most severe corrosion process in Aluminum Conductor Steel Reinforced

(ACSR) type of cable is corrosion of the inner aluminum strand which can result in

strand breakage and consequent line failure. The corrosion of the cable may cause by an

aqueous solution that containing chloride ion. This ion could penetrate between the

aluminum strands of the conductor and may attack the galvanizing on the steel core. The

steel substrate will form a dissimilar metal, galvanic cell between aluminum and iron.

Sea salt and industrial halides may easily effect the corrosion. Figure 2.9 shows an effect

of corrosion occurred in aluminum conductors [21].

Figure 2.9: Effect of corrosion occurred in aluminum conductors [21]

19

The Corrosion may continue due to time changing and with the loss section of

aluminum strand it will affects the current carrying capability. It also could cause a loss

of mechanical strength of the conductor. Due to preventing this corrosion occurred,

amount of greases are used in the conductor. With sufficient grease within the

conductor, it could prevent the conductor from the internal corrosion. Figure 2.10 shows

a minimum life expectancy of core greased zebra.

Figure 2.10: Minimum life expectancy of core greased zebra [21]

20

2.7 Previous Research

This sub topic discuss about the related literature about mobile robot. Summary about

mobile robot and all the previous works can be summarized in Table 2.2. Meanwhile,

Table 2.3 represents the comparison between flying design robot, gripping design robot

and wheel design robot. In Table 2.3 shows an advantages and disadvantages of types of

gripper.

Table 2.2: Summary of previous research about mobile robot

Author Tittle Summary of paper

Songyi, Wen

Xuefeng, Dong

Hang, and Weng

Tao

Development of a

Self-balance Dual-

arm Robot for

Inspection of High-

voltage Power

Transmission Lines

[22]

This paper proposes a climbing robot for

inspection of high-voltage power

transmission lines. The robot is based on

a self-balance dual-arm mechanism. It

has the capability of avoiding dampers,

spacers, suspension clamps and strain

clamps, spanning between lines and

climbing on much steep cable. It is

dedicated for the inspection of single

cable, double bundle cables and four

bundle cables whether the cables are

powered on or not. This paper mainly

demonstrates the mechanical design, the

principle of robot altitude control and the

driving technique of the joints. The

simulation results based on ADAMS

confirm that the mechanical design is

reasonable. The practical model of the

robot which could be manipulated by a

remote controller is also mentioned in

this paper.

Guangping Hao,

Fanzhu Meng,

Hongzhe Li,

Zhihong Wang,

Zhaonan Zhong

The Design of

Cable-Climbing

Robot [23]

This paper has proposed a cable-

climbing robot design as climbing robot

which is a rod-chain combination that

can be installed on the ground and

carried easily. The driving force of the

cable-climbing robot can automatically

adjust as needed and adapt to the cable's

diameter. The static and dynamic

analysis of the climbing robot shows the

21

driving scheme is reasonable, and the

three-dimensional modeling verifies its

rationality.

Minbo Zheng,

Yuntang Li,Jun Li,

Keming Yuan

Structure Design and

Kinematical

Analysis of a New

Type Cable

Climbing Robot [24]

In this paper, to meet the urgent

requirements of automatic operation for

cable inspection and maintenance, a new

type continuous moving cable robot

structure has been designed. The robot

has six wheels and driven by three

motors, which makes the robot can move

faster and more stable even there are

barriers along cable. Firstly, the

mechanism and working principle of the

robot is described. Then the kinematics

characteristics of the robot are analyzed

based on working condition. The

adhesive force, critical driving force and

the maximum driving force are

calculated considering the dynamic

demands of the robot working in

obstacle-surmount and non-obstacle-

surmount state. Lastly, the motor

parameters are decided according to

forces requirement.

ND Hewapathirana,

L Uddawatta, JP

Karunadasa, T

Nanayakkara

Analysis on Four

Legged

Multipurpose Rope

Climbing Robot [25]

This paper discusses the steady state

dynamic behavior of a four legged

multipurpose rope climbing robot. The

kinematic structure of the robot has been

designed to maximize the stability in the

rope climbing application while

depending on a minimum number of

actuators. The paper presents the

derivation of kinematics and dynamics

of the robot. Detailed simulations carried

out based on the dynamics of the robot

demonstrate that state trajectories of the

center of mass of the robot stays within

dynamically stable bounds for bounded

control inputs.

22

Fengyu Xu,

Xingsong Wang

A Wheel-Based

Cable Climbing

Robot With

Descending Speed

Restriction [26]

This paper has purposed a new wheel-

based cable climbing robot which is able

to climb up the vertical cylindrical cable

on the cable-stayed bridge. The design of

the robot is closed hexagonal body

shaped. This is to clasp on the cable. The

robots were analyzed and the balanced

torque of the mechanism has been

included in this paper. This robot could

climb up a cable with diameters varying

from 65mm to 205mm with payloads

below 3.5kg. A gas damper with a slider-

crank mechanism is introduced to

exhaust the energy generated by the

gravity when the robot is slipping down

along the cables. Several climbing

experiments have been performed on

real cables. The results show the

capability of the purposed robot.

Trevor Lorimer, Ed

Boje

A Simple Robot

Manipulator able to

Negotiate Power

Line Hardware [27]

This paper presented the design of a

power line inspection robot that is

capable of climbing around obstacles

including strain towers. It was shown

through negotiation sequences that these

capabilities are achievable with a

kinematically simple manipulator design

that has 5 degrees of freedom. Two

prototype robots were presented, a

proof-of-concept, and a field-testable

unit. Several aspects of the hardware

design were briefly discussed, including

improvements that were made on

prototype 2 as a result of the experience

acquired during the operation of

prototype 1. A summary of the robot's

hardware design is also provided, with

experience gained on a first prototype

influencing major design aspects on a

second prototype, which in turn has

resulted in a far more robust, field-

oriented machine.

23

J. Maempel, T.

Koch, S. Koehring,

A. Obermaier, H.

Witte

Concept of a

Modular climbing

robot [28]

The modular robot system consists of

different heterogenic types of modules,

passive connector elements, control

hardware, power supply. Due to the

modular concept it is possible to

configure different setups of the robot. In

this way, the mechanics of the robot can

be adapted to the requirements of the

climbing task. In comparison to other

climbing robots, a generalist system is

realized. The system is remote-

controlled by the user via game pad. Its

mass depends on the configuration and is

in the range of m = 1.2 kg. A sensory

system is capable of being integrated for

detecting the contact between robot and

substrate. Safety and robustness of the

locking on the substrate can be

controlled. A reference system is built,

capable to climb pipe-like substrates.

Servo drives are suitable for this design

of robots. In future the system will be

enhanced, to be able to climb not only on

pipe-like structures, but also on flat

surfaces. Different modules could be

combined to climbing robots, optimized

to different applications. In this way,

robot configuration could be tested for

service robots, for industrial robots or for

scientific robots.

Jaka Katrasnik,

Franjo Pernus,

Bostjan Likar

A Survey of Mobile

Robots for

Distribution Power

Line Inspection [29]

The purpose of this paper is to present

the most important achievements in the

field of distribution power line

inspection by mobile robots. Stimulated

by the need for fast, accurate, safe and

low-cost power line inspection, which

would increase the quality of power

delivery, the field of automated power

line inspection has witnessed rapid

development over the last decade. This

paper addresses automated helicopter

inspection, inspection with flying robots

and inspection with climbing robots. The

first attempts to automate power line

24

inspection were conducted in the field of

helicopter inspection. In recent years,

however, the research was mostly

focused on flying and climbing robots.

These two types of robots for automated

power line inspection are critically

assessed according to four important

characteristics: design requirements,

inspection quality, autonomy and

universality of inspection. Besides, some

general not yet identified problems and

tasks of inspection robots, which should

be addressed in the future, are presented.

148

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a wireless camera supervision robot (csr-bot) for

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