a wireless camera supervision robot (csr-bot) for
TRANSCRIPT
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°.
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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
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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
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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
Image Viewer program
4.26 Example of decreasing the brightness of the image by the 96
Image Viewer program
4.27 Example of increasing the brightness of the image by the 96
Image Viewer program
4.28 Ability to preview the histogram graph of the image by the 97
Image Viewer program
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
4.64 Video recorded from Webcam camera 2 for PVC pipe 138
4.65 Video recorded from Webcam camera 3 for PVC pipe 138
4.66 Video recorded from Webcam camera 1 for Nylon rope 139
4.67 Video recorded from Webcam camera 2 for Nylon rope 139
4.68 Video recorded from Webcam camera 3 for Nylon rope 140
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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