Pv cleaning robot project final

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PV PANELS CLEANING ROBOTICS
SYSTEM
Graduation project report submitted to the faculty of
Mechatronics Engineering Department
The Hashemite University
in partial fulfillment
of the requirements for the degree of
Bachelor in Mechatronics Engineering
By
Mohammad Al-khawaldeh (1231567)
Ismael AL-Sabateen (1234224)
Khalid Alqudah (1340208)
Supervised by
Dr. Mohammad Abu-Mallouh
2016/2017

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ABSTRACT
With growing costs of electricity and concern for the
environmental impact of fossil fuels, implementation of eco-friendly
energy sources like solar power are rising. The main method for
harnessing solar power is with arrays made up of photovoltaic (PV)
panels. Accumulation of dust and debris on even one panel in an
array reduces their efficiency in energy generation considerably and
emphasizes the need to keep the panels’ surface as clean as
possible.
The goal of our project is to create an automated solar panel
cleaner that will address the adverse impact of soiling on commercial
photovoltaic cells. Specifically, we hoped to create a device that
increases the maximum power output of a soiled panel by 10%
(recovering the amount of power lost).
Furthermore, autonomous cleaning robots are often only
economical on a larger scale due to both installation costs and the
fact that custom-made parts are needed to fit the plant.

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TABLE OF CONTENTS
ABSTRACT.......................................................................................................................................ii
TABLE OF CONTENTS...................................................................................................................iii
LIST OF FIGURES...........................................................................................................................v
LIST OF SYMBOLS AND ABBREVIATIOnS..................................................................................vii
ACKNOWLEDGEMENTS..............................................................................................................viii
Chapter 1 : Introduction .................................................................................................................1
1.1 Problem statement..............................................................................................................2
1.2 Motivations and Importance..............................................................................................3
1.3 Methodology and Implementation ....................................................................................3
1.4 Overview..............................................................................................................................4
1.4.1 Traditional PV Cleaning Methods ..............................................................................4
1.5 Future Technology..............................................................................................................12
1.5.1 Mazumder’s technology .............................................................................................12
1.5.2 Nanoman Solar Panel Coat.........................................................................................13
Advantages of Using Nanoman Solar panel Coating and Protection .......................................13
Surfaces That Nanoman Solar Panel Coat can protect .............................................................14
Chapter 2 : System Description and Design ..................................................................................15
2.1 System Description.............................................................................................................15
2.2 System Design ....................................................................................................................15
2.3 Block Diagrams and Flowcharts later.................................................................................16
Chapter 3 : Mechanical Design......................................................................................................19
3.1 Frame Design......................................................................................................................19
3.2 Robot Body Design.............................................................................................................20
3.3 Calculations and Part Selections.........................................................................................22
3.4 Final Design........................................................................................................................23
Chapter 4 : System Components....................................................................................................24
4.1 Drive Systems.....................................................................................................................24
4.1.1 Motor Selection and Description................................................................................24
DC Servo motor Advantages....................................................................................................24
Stepper motor Advantages........................................................................................................24
DC Servo motor Disadvantages................................................................................................25
Stepper motor Disadvantages ...................................................................................................25

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4.1.2 Motor Selection analysis ............................................................................................26
4.2 Sensors and Signal Condition Circuits ...............................................................................29
4.3 Power System .....................................................................................................................30
4.4 data logging ........................................................................................................................31
4. 4.1 data logging calculation..........................................................................................34
Chapter 5 : Control Design ............................................................................................................39
5.1 Controller selection.............................................................................................................39
5.2 Process Flow Chart.............................................................................................................41
Chapter 6 : The Budget and other problems we faced it:...............................................................42
6.1 : The Budget: ......................................................................................................................42
Chapter 7 : Conclusions and Recommendations............................................................................45
7.1 Conclusions ........................................................................................................................45
The system can be applicable at any plant, it should guarantee a zero pressure on the PV cells
and easy to control and maintain. .............................................................................................45
Unfortunately, the disadvantage is that it need to be installed manually to the next array.......45
Rainy region could create a problem for this design, because rain creates mud, and mud is
hard to clean by using brushes only..........................................................................................45
7.2 Future Work........................................................................................................................45
REFERENCES ..............................................................................................................................46

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LIST OF FIGURES
Figure 1.Cleaning Using Mops and Potable Water..........................................................................4
Figure 2.Elite team cleaning solar panel.[4] ....................................................................................4
Figure 3. Cleaning Using Pressurized water.[5] ..............................................................................5
Figure 4. Cleaning Solar Panels Using Compressed Air. ................................................................7
Figure 5. Cleaning Solar Panels Using Water Spray.[7]..................................................................8
Figure 6. Cleaning Solar Panels Using Steam. ................................................................................9
Figure 7. Cleaning Solar Panels Using Steam creepy robot. .........................................................10
Figure 8..........................................................................................................................................11
Figure 9. Frame motor block diagram ...........................................................................................16
Figure 10. Brush motor block diagram..........................................................................................16
Figure 11. Body motor block diagram...........................................................................................16
Figure 12........................................................................................................................................17
Figure 13........................................................................................................................................18
Figure 14. Frame of the robot ........................................................................................................19
Figure 15........................................................................................................................................20
Figure 16. Robot body ...................................................................................................................21
Figure 17........................................................................................................................................21
Figure 18. Final design of the robot...............................................................................................23
Figure 19........................................................................................................................................23
Figure 20.DC MOTOR GEARBOX WHEEL AND TYRE..........................................................27
Figure 21.DC MOTOR WITH ENCODER DISK 41 LINES .......................................................28
Figure 22.Proximity sensor ( Photoelectric sensor diffuse type) ...................................................29
Figure 23.Limit switch Sensor......................................................................................................30
Figure 24.Mighty Max Battery 12v ...............................................................................................31
Figure 25.Our Data Logger............................................................................................................32
Figure 26.Current Sensor...............................................................................................................33
Figure 27.Voltage Sensor...............................................................................................................33
Figure 28........................................................................................................................................34
Figure 29.100 ohm 7w Resistor.....................................................................................................35
Figure 30........................................................................................................................................35
Figure 31. Arduino Mega...............................................................................................................39
Figure 32.H-Bridge Module...........................................................................................................40
Figure 33.Relay Module ................................................................................................................40

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Figure 34........................................................................................................................................41
LIST OF Tables
Table 1 :Shows The Advantages And Disadvantages For Manual Cleaning Of Solar Panels. .......5
Table 2. Advantages And Disadvantages For Cleaning Solar Panels Using Pressurized Water.....6
Table 3. Advantages And Disadvantages for Cleaning Solar Panels Using compressed air.[6] .....7
Table 4.Advantages And Disadvantages for Cleaning Solar Panels Using Water Spray.[7] ..........8
Table 5. Advantages And Disadvantages for Cleaning Solar Panels Using Steam.[8] ...................9
Table 6. Advantages And Disadvantages for Cleaning Solar Panels Using Steam Creepy
Robot.[9]........................................................................................................................................10
Table 7.Advantages And Disadvantages for Cleaning Solar Panels Using Eccoppia E4.[9] ........11
Table 8. Advantages of DC and Stepper motors............................................................................24
Table 9. Disadvantages of DC and Stepper motors. ......................................................................25
Table 10: The Budget.....................................................................................................................42

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LIST OF SYMBOLS AND ABBREVIATIONS
GWh
Gal/MWh
Gigawatt per hours
Gallons per megawatt hour
M Mass
V Volume
A Cross Sectional Area
ρ
LS
Density
Limit Switch

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ACKNOWLEDGEMENTS
We would like to express our special thanks of gratitude to our
principal Dr.Mohammad Abu-Mallouh who gave us the golden
opportunity to do the wonderful project on solar panels cleaning
system, which also helped us doing a lot of research and we came to
know about so many new things we are really thankful to them.
secondly, we would also like to thank our parents and friends
who support us.

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CHAPTER 1 : INTRODUCTION
Growing interest in renewable energy has led the solar
photovoltaic (PV) industry to expand notably in the last decade. In the
year 2014 a staggering a 3.03-million gigawatt hours (GWh) of
electricity was produced in the European Union covering 3 percent of
the total electricity demand [1]. Because Photovoltaic energy is an
accessible technology, it has become a popular investment for
companies as well as for residential users. Consequently, this
demand has stimulated the research for increasing the overall output
power of PV systems causing laboratories all over the globe to work
hard on making the technology both more efficient and cost effective.
solar photovoltaic (PV) industry is expanding worldwide, due to
its technological and economic advantages . The PV conversion
efficiency ranges from 10 to 13% in commercial level. However, the
outdoor installed PV modules efficiency may reduce by 10 to 25%.
The reduction in the effectiveness referred to the losses in the
inverter, wiring and dust pollution . Any substance spreads in the air
includes soil and dust particles (suspended dust), smoke, fog and
particulate matters called dust. Dust formed from inorganic and
organic substances of terrestrial origin . Dust consists of substances
like sand storms, bacteria, factories’ smoke, pollen, forest fires and
volcanoes vapors. They also include the suspended solid
atmospheric particles that remain in the air for long periods. These
particles can transfer with wind movements for long distances . The
areas characterized by high dust concentration levels suffer from the
significant losses due to dust pollution. Many valuable studies
confirmed that the airborne dust deposition on the outdoor
photovoltaic (PV) modules decrease the transmittance of the cell
glazing. Also, it results in a significant degradation of solar conversion
efficiency of PV modules. The dust deposition on the outdoor PV
studies focused on the glazing transparency performance. Ref.

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studied the PV array output near Riyadh city in Saudi Arabia. The
results indicated that a 32% reduction in energy output observed
during the PV exposure to outdoor conditions about eight months. In
the United Arab Emirates, El-Nashar investigated the dust
accumulation impact on the solar collectors’ performance for different
periods. The study attested that the monthly glass transmissivity
decline rate was between 10% in summer and 6% in winter. In Iraq
adjacent to the formerly mentioned countries, Ref. studied the
derestrict environmental conditions impact on the heliostats mirrors of
CSP plant. The study revealed that primarily affected factor was the
dust that accumulated on heliostats. [2]
However cleaning solar panels is not always as straightforward.
To begin with, there is the issue of accessibility. Due to the fact that
PV panels often are situated on dangerous and difficult to reach
places, it might be hard to clean them manually and it takes time to
do it safely. Secondly, cleaning a panel only once a year might not
have a significant impact on the yearly energy yield for the simple
reason that dirt stacks up again in a short period of time making the
difference negligible. Especially if you need to contract someone to
clean the panel for you, it might just not be economical. However,
leaving panels uncleaned might not be wise either since soiling can
lead to permanent damage of the glass limiting the lifespan of the
installation.
1.1 PROBLEM STATEMENT
Solar panels work by allowing light into the solar cells. The more
light that hits a panel, the more power it will generate. Due to the
upwards angle of solar panels, they are more prone to bird droppings
and a build-up of general dust, sand, moss and dirt that does not
wash off with just rain. This reduces the amount of light hitting the
panel and reduces its output. As the projected energy figures claimed

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by solar panel manufacturers and installers are based on the
optimum performance of clean solar panels, this build-up of dirt can
adversely affect the panel’s ability to meet those projections.
Therefore, it is important to clean solar panels in order to protect and
maintain your investment. Regular solar panel cleaning will also help
you to make the most of the government feed-in tariff.
1.2 MOTIVATIONS AND IMPORTANCE
The full generating capacity of PV solar in Jordan will not be
realized due to accumulation of dirt and debris (i.e. "soiling") on
photovoltaic solar panels that decreases power output. Many are
located in dusty, arid climates where long dry periods are common.
Furthermore, run-off on the panels from the rainwater leaves
stains and scales that reduce their efficiency. Existing cleaning
technologies are expensive, dangerous (e.g. manual cleaning on
residential roofs), or impractical for arid PV solar installations (e.g.
water-based cleaning in desert locals). PV Cleaner is an inexpensive,
autonomous, and waterless mechanical device that maximizes solar
panel power output while minimizing owner involve men.
1.3 METHODOLOGY AND IMPLEMENTATION
In our project we introduce the idea of special robot for PV
cleaning, specialized in clean solar cell from dirt accumulation as well
as to reduce the power loses.
PV cleaning robot can be used without need for human
intervention to speed up the work in the large PV farms. The robot

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move in the tracks that are mounted on the photovoltaic panel
structure.
1.4 OVERVIEW
With significant progress in the field of innovation cleaning solar
panels there are many ways of cleaning PV cells, each method has
advantages and disadvantages in terms of cost and efficiency, it is
possible that the way to be effective but high cost, or less expensive
but low efficiency.
1.4.1 TRADITIONAL PV CLEANING METHODS
I. Manual cleaning using mops and potable water.
As shown in the Figures (1.4.1.1 and 1.4.1.2), this method is
easy to use and the equipment doesn’t cost much, but since it need
water and man power the coast of this operation is very high.
Figure 2.Elite team cleaning solar panel.[4] Figure 1.Cleaning Using Mops and
Potable Water

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II. Pressurized water
As shown in the Figure (1.4.2), this method needs a huge
amounts of water so, it is not logical to immolate water to get
electricity, especially that the regions that are rich of sun power are
poor in water.
Figure 3. Cleaning Using Pressurized water.[5]
Table 1 :Shows The Advantages And Disadvantages For Manual Cleaning Of Solar Panels.
Advantages Disadvantages
• easy to use.
• usable for distress area.
• no need for control system.
• very low maintenance.
• High initial coast.
• Consumption water highly
• Need human all the time.
• Not usable for large farms.
• Not reachable for all
modules

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Table 2. Advantages And Disadvantages For Cleaning Solar Panels Using Pressurized Water.
III. Compressed Air
• Shifting the dust from one place to another.
• Energy intensive.
• Challenging mobilization.
• Indirect negative effect on personal property.
• It is usable for large farms
of solar panel.
• It is controllable and
reprogrammable.
• No need for hard working
by human.
• Reachable for all modules.
• Very high initial coast.
• Movement from string to
string is difficult.
• Consumption high amount
of water 20 gallons per
megawatt hour
(gal/MWh).[5]
• High maintenance.

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Table 3. Advantages And Disadvantages for Cleaning Solar Panels Using compressed air.[6]
• Water consumption is none.
• Low initial coast.
• Easy to control and usable.
• need power source to turn
on.
• Hard working for human
• Medium efficiency.
• unreachable for some pv
modules.
IV. Water spray Cleaning
• Need large capacity of water
• Energy is not intensive.
• Challenging control direction of water.
Figure 4. Cleaning Solar Panels Using Compressed Air.

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• It useful for dust and small stacks.
Table 4. Advantages And Disadvantages for Cleaning Solar Panels Using Water Spray.[7]
• The system is not complex.
• Easy to control and usable .
• We can add soap for biter
clean
• Water consumption is very
high.
• We need external hardware
on the pv modulus
Table 4.Advantages And Disadvantages for Cleaning Solar Panels Using Water Spray.[7]
V. Steam Cleaning
Similar to using compressed water method, this method needs
water but with less amounts, as shown in Figure(1.4.5), However, it’s
ineffective because, the equipment coast much
Figure 5. Cleaning Solar Panels Using Water Spray.[7]

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VI. Creepy robot Cleaner
• Need power source 110 v.
• Energy is not intensive.
• Challenging move from sting to another.
Table 5. Advantages And Disadvantages for Cleaning Solar Panels Using Steam.[8]
• Low initial coast.
• Water consumption is low.
• Easy to control and usable.
• Hard working for human
and need hem all the time.
• Unreachable some pv
modulus
• Efficiency is low.
Figure 6. Cleaning Solar Panels Using Steam.

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VII. Eccoppia E4
This system is typically only feasible on massive solar farms where
the large numbers of panels cleaned offset their large cost.
Table 6. Advantages And Disadvantages for Cleaning Solar Panels Using Steam Creepy Robot.[9]
• No need for human.
• Efficiency is high.
• Fast and good
performance.
• Difficult to move from string
to another.
Figure 7. Cleaning Solar Panels Using Steam creepy robot.

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Table 7.Advantages And Disadvantages for Cleaning Solar Panels Using Eccoppia E4.[9]
• No need for human.
• Efficiency is high.
• Fast and good
performance.
• medium initial coast.
• Difficult to move from string
to another.
Figure 8

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1.5 Future Technology
One of the best places to put a solar panel is in the desert,
where it’s sunny. But deserts are also dusty, which means the panels
have to be washed frequently so the dust doesn’t stop them from
capturing sunlight. New technology could provide a solution–by letting
solar panels clean themselves.
1.5.1 Mazumder’s technology
The system takes advantage of the fact that most dust
particles, particularly in dry environments, have an electric charge. A
transparent electrode material such as indium tin oxide delivers an
alternating current to the top surface of the panel. As it swings
between being positively and negatively charged, it creates an
electric field that repels positively and negatively charged particles.
The electric field also helps to impart a charge to uncharged
dust particles, allowing them to be quickly repelled as they come in
contact with the panel. The researchers have designed the system so
that the electric field works its way from one side of the solar panel to
the other, gradually moving the dust along until it falls off.
The system doesn’t use much energy–electrical current is small
and typically it only needs to be on between two and five minutes a
day, Mazumder says. The system could include a sensor to
determine when the panel needed cleaning. The technology doesn’t
work if the dust gets wet and muddy, so it should be triggered to
remove dust before it rains, Mazumder says.
Mazumder’s technology is one of two approaches NASA has
funded for cleaning off solar panels. The other vibrates the entire
panel to shake dust loose. It’s still not clear which will prove more
practical for space missions, says Surampudi, who oversaw the

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research into both dust-clearing techniques. Using vibrations is
simpler and requires fewer modifications to the solar panel, he says.
But it does not remove fine particles as well as the electrical field
approach. For terrestrial applications, Mazumder’s technology will
have to compete with other potential approaches to cleaning off solar
cells without using water, such as blowing air on them or adding a
nonstick layer.
The electrical field technology could prove simple to produce,
Mazumder says, because many solar manufacturers already have
equipment for depositing transparent electrodes, which would
generate the electrical fields, onto panels. He says the next step is to
determine whether it will be possible to meet the researchers’ goal of
keeping manufacturing costs below about 1 percent of the total cost
of the solar panel. However, the value of the system will depend on
how dusty solar panels get in different locations. [11]
1.5.2 Nanoman Solar Panel Coat
Nanoman Solar Panel Coat is a nanotechnology enabled
coating specially engineered for use on solar panels. Once applied it
fundamentally changes the surface giving the surfaces hydrophobic
and self-cleaning properties The coating's self-cleaning effect stops
dust, pollen, pollution and bird faeces from sticking to PV panels,
keeping them clean, maintaining their efficiency, ensuring the
maximum amount of electricity is produced.
Advantages of Using Nanoman Solar panel Coating and Protection
• Reduces cleaning frequency saving energy, time and cost
• Dust and dirt are washed away with rainwater
• Is resistant to salty environments
• The water rolls-off the surface forming a Brushing Effect (Easy-
to-Clean Effect)
• Easy application through Spray

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• Material curing at atmospheric temperature.
• Stable at varying Temperatures.
• Ecologically beneficial and biologically safe.
• Resistance against dirt, algae, etc.
Surfaces That Nanoman Solar Panel Coat can protect
• Fixed Solar Panels.
• Solar powered water pumps.
• Solar powers signs.
• Mobile Solar Panels.
• Hard to reach Solar Panels.
• Remote solar panels.
• Solar farms.[12]

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Chapter 2 : System Description and Design
Our robot is a water-free robotic cleaning process combines a
powerful-soft microfiber brush supposed to remove 99% of dust daily
and keeping panels at optimal production rates.
We focus in this robot on decrease power sources used to
observe rareness this sources like water, and guarantee work the
robot in any location without need water, because the most of PV
farm derivate in the desert, and we know the difficult to existence
water in this location, and we can say that other aim is facilitation the
robot structure and ease to control it.
2.1 System Description
PV cells cleaning robot consist of a frame that move
horizontally along the array and make a path where the robot body
can move vertically to clean the cells, The brush settled to the robot
body and made of microfiber to guarantee that the PV cells will not
scratched, and it generated by a high speed DC motor. The robot
controlled using a limit switches, proximity sensors and encoder
connected to Arduino mega controller.
2.2 System Design
The design of the robot is a rolling brushes connected to a body
that traverses vertically along the frame and the frame will move
horizontally along the array, the device would not use water and
would not need to be connected to any source of water

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2.3 Block Diagrams and Flowcharts later
There are three independent motors in this system; every
motor has its block diagram.
1- Frame Motor
In charge of moving horizontally along X-axis and controlled by encoder and two
proximity sensors. See figure (2.1)
2- Body Motor
In charge of moving vertically Along Y-axis and controlled by two limit switches for determining
the direction of movement (upward and downward). See figure (2.2).
3- Brush Motor
Limit
Switch 1
Arduino
Ardduino
H-Bridge Frame
Motor
DC voltage Theta
Limit
Switch
Arduin
o
H-
Bridge
Frame
Motor
DC
voltage
Theta
Encoder Arduino H-Bridge Frame
Motor
DC voltage Theta
Figure 9. Frame motor block diagram
Figure 11. Body motor block diagram
Figure 10. Brush motor block diagram

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In charge of moving the brush, and operated by a limit switches (on and off).
See figure (12).
Figure 12

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Chapter 3 : Mechanical Design
The robot consists of three parts frame, robot body and brush.
The frame and the robot body are made of aluminum.
3.1 Frame Design
Aluminum rectangle with dimensions of 2 m by 0.4 m to cover a
whole module at each time with two motors, the first one move the
frame horizontally along the array and the other one to move the
robot body vertically and two proximity sensors to stop the frame
when it reach the edges of the array and an encoder to start the
cleaning cycle after a certain distance.
The frame dimensions chosen to cover an area equals to
quarter of plant. Width equals 0.4 meters, and length equals 2
meters, which is the width of the plant and a distance reserved for the
spool and power system.
Figure 14. Frame of the robot

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Figure 15
3.2 Robot Body Design
Aluminum square with dimensions of 0.3m contains two
microfabric brushes that move vertically from the top toward the
bottom to guarantee that the dust gets swept towards the bottom and
not just transported sideways. There will be two strokes (top to
bottom, bottom to top) to make sure that dust swept perfectly.

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Figure 16. Robot body
Figure 17

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3.3 Calculations and Part Selections.
We choose aluminum material to make our robot for its light
weight and strength
Density of aluminum (ρaluminum) = 2800 Kg/m^3
Cross sectional area of the frame (Aframe) = Aouter – Ainner = 0.02*0.02 –
0.017*0.017
Aframe = 0.000111 m2
Volume of the frame (Vframe) =Aframe*length= 0.000171*4.8 = 0.0005328 m3
Mass of frame (Mframe) = Vframe *ρaluminum
Mframe = 1.49184 Kg
Abody = 0.000111 m2
Volume of the body (Vbody) =Abody*length= 0.000171*2 = 0.000222 m3
Mass of body (Mbody) = Vbody *ρaluminum
Mframe = 0.6216 Kg
Mass os motors = 0.5 Kg
Mass of brushes = 0.4 Kg
Mass of wheels = 0.5 Kg
Total mass (Mrobot) = 3.51344 Kg

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3.4 Final Design
.
Figure 18. Final design of the robot
Figure 19

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Chapter 4 : System Components
Each chapter should begin with an introduction that tells what
you will cover in the chapter. It should tell the reader what is in the
chapter as well as its importance to the overall thesis/report. This
introduction should occur directly below the chapter heading and
does not require its own header.
4.1 Drive Systems
4.1.1 Motor Selection and Description
For the robot, there are two possible motors choice, each one
have advantages and disadvantages as shown in the tables (9 and
10) below. [6]
DC Servo motor Advantages Stepper motor Advantages
• High output power relative to motor
size and weight.
• Encoder determines accuracy and
resolution.
• High efficiency. It can approach 90%
at light loads.
• High torque to inertia ratio. It can
rapidly accelerate loads.
• Has "reserve" power. 2-3 times
continuous power for short periods.
• Has "reserve" torque. 5-10 times rated
torque for short periods.
• Motor stays cool. Current draw
proportional to load.
• Usable high speed torque. Maintains
rated torque to 90% of NL RPM
• Audibly quiet at high speeds.
• Resonance and vibration free
operation.
• Stable. Can drive a wide range of
frictional and inertial loads.
• Needs no feedback. The motor is also
the position transducer.
• Inexpensive relative to other motion
control systems.
• Standardized frame size and
performance.
• Plug and play. Easy to setup and use.
• Safe. If anything breaks, the motor
stops.
• Long life. Bearings are the only wear-
out mechanism.
• Excellent low speed torque. Can drive
many loads without gearing.
• Excellent repeatability. Returns to the
same location accurately.
• Overload safe. Motor cannot be
damaged by mechanical overload.
Table 8. Advantages of DC and Stepper motors

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DC Servo motor Disadvantages Stepper motor Disadvantages
• Requires tuning to stabilize feedback
loop.
• Motor runs away when something
breaks. Safety circuits are required.
• Complex. Requires encoder.
• Brush wear out limits life to 2,000 hrs.
Service is then required.
• Peak torque is limited to a 1% duty
cycle.
• Motor can be damaged by sustained
overload.
• Bewildering choice of motors,
encoders, and servodrives.
• Power supply current 10 times average
to use peak torque.
• Motor develops peak power at higher
speeds. Gearing often required.
• Poor motor cooling. Ventilated motors
are easily contaminated.
• Low efficiency. Motor draws
substantial power regardless of load.
• Torque drops rapidly with speed
(torque is the inverse of speed).
• Low accuracy. 1:200 at full load,
1:2000 at light loads.
• Prone to resonances. Requires
microstepping to move smoothly.
• No feedback to indicate missed steps.
• Low torque to inertia ratio. Cannot
accelerate loads very rapidly.
• Motor gets very hot in high
performance configurations.
• Motor will not "pick up" after
momentary overload.
• Motor is audibly very noisy at
moderate to high speeds.
• Low output power for size and weight.
Table 9. Disadvantages of DC and Stepper motors.
A stepper motor would have a couple advantages in terms of
controllability over a DC motor; each step has a defined angular
rotation. In addition, it can deliver a lot of torque at low speeds and
have reasonable currents at stall torque, so it would be the
reasonable option.
However, for making the robot be a product that is easy to
install, the motors are preferably built into the robot.
For the brushes, a motor with a high speed and a low
torque is the best choice, since that the brushes are light and
cleaning process needs high speed.

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4.1.2 Motor Selection analysis
Summation of forces = 0
Fmotor-fload=0
Fm=fload
Fm=mg=2*9.81=19.62n
Torque=fm X r=19.62*0.03 = 0.5886n. m
We chose motor with 0.6nm and speed of 95rev/min to maintain the horizontal
movement in 1 sec
Distance severed per 1 revolutin of motor * number of revolutions/60 =
2*3.14*0.03*95/60=0.298m/sec
Speed desired = 30 cm/sec

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Figure 20.DC MOTOR GEARBOX WHEEL AND TYRE
Description:
DC motor with right angled drive reduction gerbox and rubber tyred wheel. This unit is ideal for
robot or toy vehicle construction. Ideal for Arduino and other development systems.
Light weight plastic construction gearboxmetal motor rated at 3-6VDC and soft rubber tyre.
wheel can fit to the left or right of the gearbox and motor can be run in both forward and reverse
directions.
Voltage: 3-6VDC
Current: 80-150mA
No Load Speed: 3V-125 rev/min 5V-200 rev/min 6V-230 rev/min
Load Speed: 3V-95 rev/min 5V-160 rev/min 6V-175 rev/min
Output Torque: 3V-0.8kg.cm 5V-1.0kg.cm 6V-1.1kg.cm
Wheel Diameter: 65mm including tyre
Wheel Width: 25mm
Gearbox/Motor Dimensions: 20mm x 22mm x 65mm
Weight: 50grams

28
Figure 21.DC MOTOR WITH ENCODER DISK 41 LINES
DC motor with Speed encoder code disk 41 lines
Voltage Load Current Speed
5V 60mA 1600 rpm
12V 80mA 4300 rpm
24V 120mA 8600 rpm
Encoder grid: 41 lines

29
4.2 Sensors and Signal Condition Circuits
The robot has 2 limit switches, 2 proximity sensors and an
encoder, which are located on the frame, to give an indication for the
frame position on the array so that the controller can decide whether
it should stop and starting cleaning process or to keep moving to the
end of the array. LS1 and LS2 located in a frame, to determine if the
brush is located at start position or end position in Y-axis. Proximity
sensors are located on the frame, to determine if the frame reached
to the end of the array in the X-axis. (Figure 22)
Figure 22.Proximity sensor ( Photoelectric sensor diffuse type)
Output Type : NPN NC (Normally Close;
Diameter of Head : 18mm;
Detecting Distance : 5-30cm (adjustable)
Detecting Object : Metal, non metal (body, hand, paper.), transparent or
opaque body.
Supply Voltage : DC 10-30V;
Current Output : 200mA;

30
Figure 23.Limit switch Sensor
Applicable to AC DC control circuits Designed to control the movement of a
mechanical part.
Rating: AC 250V/7. 5A, 125V/15A, DC 125V/0. 6A, 250V/0. 3A
4.3 Power System
Since the motors selected were a DC motor, since the high speed
motor needs 24 volts to operate at its rated speed and the other
motor needs 12 volts, two 12 volts batteries are needed.

31
Specifications:
Voltage: 12 Volt
Amperage: 7.2 AH
4.4 data logging
in our project, we use 90w pv cell for testing the efficiency of
our project and to maintain that we need to measure the voltage and
current it provide over time.
To do that we Should use Data Logger to save values of
current and voltage of PV cell. but, the Big Problem It’s High price of
Data Logger in Jordan.!!
Figure 24.Mighty Max Battery 12v

32
So, to do that we try build a dummy load to consume the power
generated from the cell and connect a voltage and current sensors to
read the data every half a second and save it into a SD card module.
We use Arduino, dummy load, current & voltage sensors and
micro SD card Shield.
Figure 25.Our Data Logger

33
Figure 26.Current Sensor
Current Sensor 10A Module
Current sensor chip: ACS712ELC
5V power supply, on board power indicator, Low noise analog signal path
Figure 27.Voltage Sensor
Voltage Sensor module for Arduino
Net Weight: 4g;
PCB Board Size: 27 x 14mm / 1.1" x 0.55"(L*W)
Max Voltage Range: 25V

34
Figure 28
4. 4.1 data logging calculation
Pmax =90w
Pmax = Vmax*imax=18.6*4.85
R=Vmax/imax=18.6/4.85=3.83ohm

35
Figure 29.100 ohm 7w Resistor
100 ohm 7w Resistor
We choose 100 ohm 7 w resistor and connect 25 of them in parallel to maintain r
equivalent of 4 ohm and total power more than 90w
Ptotal = 7*25=175w
Figure 30

37
Arduino Code For Our Data Logger:
#include <SPI.h>
#include <SD.h>
const int chipSelect = 53;
void setup() {
pinMode (stopPin,INPUT);
Serial.begin(9600);
while (!Serial) {
;
}
Serial.print("Initializing SD card...");
if (!SD.begin(chipSelect)) {
Serial.println("Card failed, or not present");
return;
}
Serial.println("card initialized.");
}
void loop() {
String dataString = "";
for (int analogPin = 0; analogPin < 2; analogPin++) {

38
int sensor = analogRead(analogPin);
dataString += String(sensor);
if (analogPin < 1) {
dataString += ",";
}
}
File dataFile = SD.open("datalog.csv", FILE_WRITE);
if (dataFile) {
dataFile.println(dataString);
dataFile.close();
Serial.println(dataString);
}
else {
Serial.println("error opening datalog.csv");
}
delay(500);
}

39
Chapter 5 : Control Design
5.1 Controller selection
Arduino mega
The Mega 2560, as shown in figure (5.1), is a microcontroller
board based on the ATmega2560. It has 54 digital input/output pins
(of which 15 can be used as PWM outputs), 16 analog inputs, 4
UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB
connection, a power jack, an ICSP header, and a reset button. It
contains everything needed to support the microcontroller; simply
connect it to a computer with a USB cable or power it with a AC-to-
DC adapter or battery to get started.
Figure 31. Arduino Mega

40
H-Bridge module
An H-bridge shown in figure (5.2) is an electronic circuit that
enables a voltage to be applied across a load in either direction.
These circuits are often used in robotics and other applications to
allow DC motors to run forwards and backwards. One H-Bridge can
drive two motors.
Figure 32.H-Bridge Module
Relay module
The module is uses SRD relay module, as shown in figure (5.3), to
control high voltage electrical devices. (Maximum 250V). It can be
used in interactive projects and can be used to control the lighting,
electrical motors and other equipment. It can be controlled directly by
a wide range of microcontrollers and can be controlled through the
digital IO port, such as solenoid valves, lamps, motors and other high
current or high voltage devices.
Choosing this relay was enough since that the brush motor need
to operate in one direction.
Figure 33.Relay Module

41
5.2 Process Flow Chart
Process flow chart is the easiest way to show how the real
system should work from the beginning of the process to the end.
(Figure 33)
Move in +ve x-axis
Start
Move in +ve y-axis
Stop frame motor, start
cleaning, and move in
the –ve y-axis
Does the frame
move 0.3m?
Does the body reached
the limit switch1
Does the body reached
the limit switch2 Stop cleaning
Does the right proximity
sensor high (reached the
start of the array)
Move in –ve x-axis
Does the left proximity
sensor high (reached the
end of the array)
End
No
No
No
No
No
Figure 34

42
Chapter 6 : The Budget and other problems we
faced it:
6.1 : The Budget:
Part Quantity price
Frame 1 15 JD
Rail 1 5 JD
Motors 3 50 JD
Multimeter 1 15 JD
Arduino-Mega 1 12 JD
Arduino-Cables 2 7 JD
Brush 2 10 JD
Limit Switch 2 5 JD
Relay module 1 2 JD
H-Bridge module 1 7 JD
Pulleys and Belts 1/1 7 JD
Wheels 4 10 JD
Bearing 2 7 JD
Power Supply 1 25 JD
Bread Board 1 2.5 JD
Other 20 JD
Overall 26 199.5 JD
Table 10: The Budget

43
6.2: Challenges and problems we face it:
6.2.1: Problem finding pieces:
We encountered problems in the location of the pieces
of the project and its limited presence, as they are available
in certain places, in addition to the existence of counterfeit
pieces, which did not serve our work well.
6.2.2: Construction problems:
In view of our project and the existence of different
types of frames such as iron and aluminum and the difficulty
of connecting parts, because each type of metal has a
different method of connection and is available only by
specialists.
There was another problem in turning in terms of where the
technicians and materials were appropriate as well as the time taken,
as the lathing process requires high professionalism and accuracy in
the work, because each error may cost the piece unsuitable for work.
This is really what happened to us when the conical pieces did
not fit our work and we had to buy these pieces ready to accelerate
the work of the project

44
6.2.3: Problem providing information:
Due to the use of many electronic parts and electrical circuits
used in the data logger, obtaining sufficient information about these
pieces and their method of operation was very difficult, and this cost
us more time and effort to solve these problems.
6.2.4 building the data logger
There are many examples of commercial data logger but the
problem is high price so we tried to build our own data logger with a
dummy load, Arduino, Micro SD Card Shield and Voltage & Current
Sensors.

45
Chapter 7 : Conclusions and Recommendations
7.1 Conclusions
The system can be applicable at any plant, it should guarantee
a zero pressure on the PV cells and easy to control and maintain.
Unfortunately, the disadvantage is that it need to be installed
manually to the next array.
Rainy region could create a problem for this design, because
rain creates mud, and mud is hard to clean by using brushes only.
7.2 Future Work
The next step for our project is finding a mechanism that allows
the project to move through spaces between arrays easily without
human factor.

46
REFERENCES
[1] www.ec.europa.eu/eurostat/statistics-
explained/index.php/Electricity_production,_consumption_and_
market_overview
[2] https://www.researchgate.net/profile/Miqdam_Chaichan/publicatio
n/279996720_Experimental_Investigations_of_Dust_Type_Effect_
on_Photovoltaic_Systems_in_North_Region_Oman/links/55b10d8
b08ae9289a084ab08.pdf s
[3] F. Wakim, "Introduction of PV power generation to Kuwait,"
Kuwait Institute for Scientific Researchers, Kuwait City, 1981.
[4] www.solarpowerworldonline.com/2015/02/fighting-dirty-manual-
washing-vs-automatic-cleaning-of-solar-modules/
[5] https://understandsolar.com/solar-panel-
cleaning/https://l.facebook.com/l.php?u=http%3A%2F%2Fforum.n
asaspaceflight.com%2Findex.php%3Ftopic%3D37874.0&h=gAQE
F8VXE&s=1
[6] https://solarconduit.com/shop/sun/pv-module-washing-
systems/pv-module-washing-systems/heliotex-automatic-solar-
panel-cleaning-system-90.html
[7] www.aliseogroup.it/en/en-pulizia-a-vapore
[8] www.scidev.net/mena/energy/news/Robot-cleans-solar-panels-
with-no-water.html
[9] www. ecoppia.com/ecoppia
[10] www.technologyreview.com/s/420524/self-cleaning-solar-
panels/
[11] www.nanoman.com.au/solarcoat.html
[12] John J. Craig, “introduction to robotics”, Pearson Prentice Hall,
2005
[13] Ned Mohan, “Power Electronics”, John Wiley and Sons, 2003.
[14] www.machinetoolhelp.com/Automation/systemdesign/stepper_
dcservo.html
[15] www.picbasic.org/articles/ultrasonic/ultrasonic_experiments
[16] www.bobblick.com
[17] www.microchip.com
[18] https://www.arduino.cc/

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