Desiging Of Light Weight And Compact Drone.pdf

Designing Of Light Weight And Compact Aerial System Minor Project Report

Submitted in partial fulfilment of the requirement For the award of the degree of

BACHELOR OF TECHNOLOGY in

MECHANICAL AND AUTOMATION ENGINEERING Submitted by

SAURABH SINGH (06314803616) SHIVAM (06514803616) VAIBHAV SHARMA (07614803616) GAGAN BANSAL (35414803616)

Under the Guidance of

Ms. SURABHI LATA (Assistant Professor)

DEPARTMENT OF MECHANICAL AND AUTOMATION ENGINEERING MAHARAJA AGRASEN INSTITUTE OF TECHNOLOGY (MAIT) NEW DELHI-110086 NOVEMBER 2019

CERTIFICATE This is to certify that the report entitled “Designing of light weight and compact aerial system” submitted by Saurabh Singh (06314803616), Shivam (06514803616), Vaibhav Sharma (07614803616),Gagan Bansal (35414803616)in partial fulfillment for the award of Bachelor of Technology in Mechanical and Automation Engineering from Maharaja Agrasen Institute of Technology, is a record of bona fide project work carried out by them under my supervision and guidance. To the best of my knowledge the result contained in this thesis have not been submitted in part or full to any other university for the award of any other degree or diploma.

Ms. Surabhi Lata Department of Mechanical and Automation Engineering Maharaja Agrasen Institute of Technology, Rohini

ACKNOWLEDGEMENT It gives us immense pleasure to express our deepest sense of gratitude and sincere thanks to our highly respected and esteemed guide Ms. Surabhi Lata (Lecturer MAE), MAIT Rohini, for their valuable guidance, encouragement and help for completing this work. Their useful suggestions for this whole work and co-operative behaviour are sincerely acknowledged.

We deeply express our sincere thanks to our Head of Department Dr. V.N. Mathur for encouraging and allowing us to present the project on the topic “Design of Light Weight and Compact aerial System” at our department premises for the partial fulfilment of the requirements leading to the award of B-Tech degree.

We are also highly thankful to our project internal evaluator and guide Dr. O.P Grover (Prof. MAE), MAIT Rohini, whose invaluable guidance helped us understand the project better.

Lastly, we would like to express our deep apperception towards our classmates and our indebtedness to our parents for providing us the moral support and encouragement.

Saurabh Singh (06314803616)

Shivam (06514803616)

Vaibhav Sharma (07614803616)

Gagan Bansal (35414803616)

ABSTRACT Unmanned Aerial Vehicles (UAVs) like drones and quadcopters have revolutionised flight. They help humans to take to the air in new, profound ways. The military use of larger size UAVs has grown because of their ability to operate in dangerous locations while keeping their human operators at a safe distance. Here quadcopter as a small UAV is discussed. It is the unmanned air vehicles and playing a predominant role in different areas like surveillance, military operations, fire sensing, traffic control and commercial and industrial applications. In this project we also study the effects of propeller configuration on the propulsion system efficiency of a multi-rotor. Study of quadcopter body frame model, also done, that propeller can be categorized into propeller with ducted and without ducted. This study present mechanical structure and describe all parts of quadcopter which gives good solution for a quadrotor design when its dimension and cost are the main constraints. The quadcopter configuration has a greater stability as compared to the other configurations and it is able to hover close to its target, unlike its other counter parts. The CAD model was developed following the manufacturing of the system using rapid prototyping in order to minimize the manufacturing time and cost. The modeling and simulation of the overactuated system allowed observing the behavior of the platform using different control inputs. The main objective of the project is to learn the design, construction and testing procedure of quadcopter. In the proposed system, design is based on the approximate payload carry by quadcopter and weight of individual components which gives corresponding electronic components selection. The selection of materials for the structure is based on weight, forces acting on them, mechanical properties and cost.

Keywords: Quadcopter, Propeller, Frame, Motor, Material, Meshing, flight controllers

Table of Contents Certificate

i

Acknowledgement

ii

Abstract

iii

Table of Contents

iv

List of Figures

vii

Chapter 1 Introduction 1.0 Drone application

2

1.1 Main areas of application

2

1.2 Need of drone 1.2.1 Defense 1.2.2 emergency response 1.2.3 humanitarian aid and disaster relief 1.2.4 Construction planning 1.2.5 Airlines 1.3 Timeline 1.3.1 1849 Austrian balloon 1.3.2 1916 Hewitt Spery 1.3.3 1918 Kettering bug 1.3.4 1930 radio controlled aerial aircraft 1.3.5 1940 radio plane OQ2 1.3.6 1973 Mastiff UAV 1.3.7 1982 Battlefield UAV 1.3.8 1985 large scale UAV development 1.3.9 1986 RQ2 pioneer 1.3.10 2006 UAV permitted 1.3.11 2010 parrot AR drone 1.3.12 2013 phantom 1 UAV 1.3.13 2013 Amazon drone delivery 1.3.14 2014 film and tv use

3 4 5 5 6 7 7 7 8 9 9 9 9 10 10 10 10 11 11 12 12

Chapter 2 Literature review

13

2.1 Review of Literature

13

Chapter 3 Design of aerial system

20

3.0 Classification according to size 3.0.1 very small UAV 3.0.2 small UAV 3.0.3 Medium UAV 3.0.4 Large UAV 3.1 Classification according to range and endurance 3.1.1 very low-cost close range 3.1.2 close range UAV 3.1.3 short range UAV 3.1.4 Mid-range UAV 3.2 Different type of drone 3.2.1 nano and mini drones 3.2.2 drones with small size 3.2.3 drone with medium size 3.3 Design mechanics 3.3.1 naming system of a drone frame 3.4 Drone frame style 3.4.1 true X 3.4.2 wide X 3.4.3 vertical arms 3.4.4 plus 3.4.5 HX 3.5 Drone components 3.5.1 standard propellers 3.5.2 pusher propellers 3.5.3 brushless motor 3.5.4 landing gear 3.5.5 electric speed controllers 3.5.6 flight controllers 3.5.7 the receiver 3.5.8 the transmitter 3.5.9 gps module 3.5.10 battery 3.5.11 camera 3.6 Drone mechanics 3.6.1 importance of how a quadcopter works and flies 3.6.2 vertical motion 3.6.3 turning rotation 3.6.4 how do we get the drone into this position? 3.6.5 Yaw, roll, pitch 3.6.5.1 Yaw 3.6.5.2 Roll 3.6.5.3 Pitch

20 20 20 21 21 22 22 22 22 22 22 22 23 24 25 25 26 26 26 27 27 28 28 29 29 29 30 31 31 31 32 32 32 32 33 33 33 34 35 36 36 36 37

3.7 Motor thrust calculation 3.8 Comparison of 2 different type of frames: HX & TRUE X

37 38

Chapter 4 FEM analysis

40

4.1 Meshing 4.2 Techniques 4.3 What are the different element types? 4.4 Why and when to use the elements? 4.5 Common cell shape 4.5.1 basic two-dimensional cell shapes 4.5.2 basic three-dimensional cell shapes 4.6 Classification of grid 4.6.1 structured grids 4.6.2 unstructured grids 4.6.3 hybrid grids 4.7 Mesh quality 4.7.1 based on the derivation from normalized equilateral angle 4.8 Work analysis: DRONE 4.8.1 initial steps 4.8.2 final steps

40 41 42 43 46 46 47 48 48 48 48 49 51 52 52 53

Chapter 5 conclusion

55

5.1 Conclusion 5.2 Future scope

55 55

References

57

LIST OF FIGURES Figure: 1.1Introduction

1

Figure: 1.2Drone Application

3

Figure:1.3Need in Defence

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Figure: 1.4Need in Emergency

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Figure: 1.5Disaster Need

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Figure: 1.6High altitude Planning

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Figure: 1.7Accurate work requirement

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Figure: 1.8Austrian balloons

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Figure: 1.9Hewitt-Sperry

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Figure: 1.10Radio plane OQ2

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Figure: 1.11Pioneer Reconnaissance drone

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Figure: 1.12Parrot AR Drone

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Figure: 1.13Phantom 1 UAV

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Figure: 1.14Use in Film Industry

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Figure: 3.1Very small Size

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Figure: 3.2Small Size

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Figure:3.3Medium Size

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Figure: 3.4Large Size

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Figure: 3.5Nano Type Drone

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Figure: 3.6Small Size Drone

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Figure: 3.7Medium Size Drone

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Figure: 3.8Frame Size View

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Figure: 3.9 Type of Frame

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Figure: 3.10 True X

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Figure: 3.11 Wide X

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Figure: 3.12 Vertical Arms

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Figure: 3.13 Plus Type

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Figure: 3.14 HX Type

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Figure: 3.15Drone’s Component

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Figure: 3.16Different types of Motor

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Figure: 3.17Turning Rotation

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Figure: 3.18Directional Movement

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Figure: 3.19 Yaw

34

Figure: 3.20Roll

34

Figure: 3.21 Pitch

35

Figure: 3.22Comparisiion of two Frame

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Figure: 3.23Different Views of Frame

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Figure: 4.1Meshing Introduction

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Figure: 4.2Different Element Shapes

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Figure: 4.3Meshing on Tyre Rim

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Figure: 4.4Meshing on Loaded Spring

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Figure: 4.5Different Cell Shape

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Figure: 4.63-D Cell Shape

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Figure: 4.7Different type of Grid

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Figure: 4.8Skewness based on equilateral volume

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Figure: 4.9Changes in Terms of Volume

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Figure: 4.10Changes in terms of Angle

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Figure: 4.1110mm size of Meshing

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Figure: 4.120.8mm size of Meshing

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Figure: 4.13Different View of Meshing

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Chapter 1 INTRODUCTION Drones have been around for years, and they are used for different purposes and can be of help in numerous occasions. However, these devices have become more popular in recent times and their application increases rapidly in various fields. But first of all, let’s answer the main question: “what is a drone and how we can define it”.The word “drone” has several different meanings and it origins from old English word drān, drǣn, which means ‘male bee’. When talking about a drone as an electric device, we thinking of missile or a remotecontrolled pilotless aircraft. So, what is a drone definition for this unmanned aerial vehicle? One of the most used definitions for drone is: “An unmanned aircraft or ship that can navigate autonomously, without human control or beyond the line of sight”. Another frequently used definition is: “Drone is any unmanned aircraft or ship that is guided remotely”.

Figure: 1.1 Introduction No doubt, drones are among the most advanced devices in today’s aeronautics, electronics and robotics alike. In the following text, you can find out more about the drones, how they work, what are their main features, their applications in a variety of fields, types of drones, and the future of drones

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1.DRONE APPLICATIONS: Drones are used in many areas and what’s more, there is no end when it comes to their possibilities. Therefore, the areas of applications are numerous today and there is the growing use of drones all around the world.Especially, the micro drones have become widely used lately due to their small size. 1.1Main areas of applications: 1.

Search and rescue – Drones are very useful in searching and rescuing operations. For example, they are used in firefighting to determine the amount of the certain gasses in air (CO, CO2, and the like) using the special measuring equipment.

2.

Security – Many authorities use drones to protect people during various emergencies. For instance, they are able to help coordinate a variety of security operations and can preserve evidence alike.

3.

Inspections – Many systems such as power lines, wind turbines, and pipelines can be checked by drones.

4.

Surveillance – A drone allows recording and monitoring from the sky, and therefore, they are suitable to monitor public events, protests, or any suspicious happening without being heard and seen. A great tool for the police!

5.

Science & research– They help scientists a lot in research works to observe different occurrences in nature or a particular environment from the sky. For example, drones are used to document the archaeological excavations, in nuclear accidents (measuring contamination), in glacier surveillance, to observe a volcanic eruption, etc.

6.

Aerial photography & video – With a drone that is equipped with an HD camera, you can take the fascinating photos and shot footage of great quality from the sky.

7.

Surveying & gis (mapping) – Using multi-spectral cameras and laser scanners, drones are able to create high-quality 3-D maps. Therefore, they found applications in various areas, including remote sensing, surveying & mapping, photogrammetry, precision agriculture, etc. 2

8.

Unmanned cargo system – Drones also serve in delivering of lightweight packages and bundles of all sorts. This way, you can have a safe, environmentally friendly and fast transport of goods by air.

Figure: 1.2 Drone Application In addition, these main areas of application, drones are also used in engineering, construction and pre-construction work, aviation, maritime, marketing, real estate (both residential and commercial), insurance, utilities, mining, meteorology, education, and more. Today, many government agencies, private companies, and other institutions have their private drones. 1.2 NEED OF A DRONE: Drone technology has been used by defence organizations and tech-savvy consumers for quite some time. However, the benefits of this technology extends well beyond just these sectors. With the rising accessibility of drones, many of the most dangerous and high-paying jobs within the commercial sector are ripe for displacement by drone technology. The use cases for safe, cost-effective solutions range from data collection to delivery. And as autonomy and collision-avoidance technologies improve, so too will drones’ ability to perform increasingly complex tasks. According to forecasts, the emerging global market for business services using drones is valued at over $127B. As more companies look to capitalize on these commercial opportunities, investment into the drone space continues to grow.

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A drone or a UAV (unmanned aerial vehicle) typically refers to a pilotless aircraft that operates through a combination of technologies, including computer vision, artificial intelligence, object avoidance tech, and others. But drones can also be ground or sea vehicles that operate autonomously. Below, check out the ways companies are harnessing drone technology for commercial purposes across industries 1.2.1 DEFENCE

Figure: 1.3 Need in Defence While drones have been used by the military for over a decade (the Predator UAV is among the most well-known), smaller, portable drones are now being used by ground forces on a regular basis. Military spending for this technology is expected to grow as an overall percentage of large military budgets such as the United States’ $640B defense budget, offering specialized drone manufacturers and software developers a tremendous opportunity. Many of the drones are being designed exclusively for surveillance, but others for offensive operations. Prox Dynamics, a military grade UAV manufacturer acquired by FLIR Systems in Q4’16, has become one of the many reconnaissance UAVs used by militaries around the world, including the US Marines, the British Army, the Australian Army, and Norway’s Armed Forces. 1.2.2EMERGENCY RESPONSE Innovations in camera technology have had significant impacts on the growing use of drones. UAVs outfitted with thermal imaging cameras have provided emergency response teams with an ideal solution for identifying victims who are difficult to spot with the naked eye.

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In 2017, Land Rover partnered with the Austrian Red Cross to design a special operations vehicle with a roof-mounted, thermal imaging drone. The vehicle includes an integrated landing system, which allows the drone to securely land atop the vehicle while in motion. This custom Land Rover Discovery, dubbed “Project Hero,” hopes to save lives by speeding up

response-times.

Figure: 1.4 Need in Emergency Startup companies and universities are also designing systems intended for search and rescue. Flyability, developer of a collision-tolerant UAV, has performed particularly well in confined areas with limited lines of sight — environments often encountered by emergency response teams. 1.2.3. HUMANITARIAN AID & DISASTER RELIEF

Figure:1.5 Disaster Need In addition to emergency response, drones have proved useful during times of natural disaster. In the aftermath of hurricanes and earthquakes, UAVs have been used to assess damage, locate victims, and deliver aid. And in certain circumstances, they are being used to prevent disasters altogether.

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To help monitor and combat forest fires, surveillance drones outfitted with thermal imaging cameras are being deployed to detect abnormal forest temperatures. By doing so, teams are able to identify areas most prone to forest fires or identify fires just 3 minutes after they begin. While recreational drones are strictly prohibited in active forest fire regions, they have proved useful when operated by the appropriate teams. 1.2.4. CONSTRUCTION PLANNING

Figure: 1.6 High altitude Planning One of the most popular commercial use cases for drones is construction planning and management. Software developers have created solutions that analyze construction progress with regularly captured data. While ground surveying is still a critical part of construction planning and monitoring, the use of drone data has become increasingly important. Camera technology is used to monitor buildings and gauge topography and soil type throughout the construction lifecycle. Skycatch offers these solutions in a monthly software subscription. Their software can pair with a self-manufactured Skycatch UAV, or with a number of DJI drones. Dronomy offers a similar suite of software solutions intended to enhance project monitoring and site management.

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1.2.5. AIRLINES

Figure:1.7 Accurate work requirement Compliance is a challenge for many industries, but the airline industry must adhere to particularly

stringent levels

of

regulatory

standards.

FAA

inspections

vary

in

comprehensiveness, but basic inspections are conducted after every 125 hours of flight time. Additionally, airlines are expected to conduct their own routine inspections before every flight. In an attempt to improve this process, Intel partnered with Airbus to conduct exterior aircraft inspections with UAVs. Intel supplied the drones (gained through their acquisition of Ascending Technologies in 2016), which are outfitted with cameras that allow them to collect images and data that can be used to create detailed, 3D-models of the Airbus fleet. Airbus has also launched its own drone subsidiary called Airbus Aerial, which looks to provide inspection solutions across a variety of industries. CanardDrones, meanwhile, provides inspection solutions for airports rather than aircrafts.

1.3 TIMELINE: 1.3.1 1849 – Austrian balloons: Austrian balloons are the earliest recorded use of unmanned aerial vehicles. On August22, 1849, Austrians used balloons loaded with explosives to attack the city of Venice, Italy. The UAV balloons were rather large, twenty-three feet in diameter, and exploded upon impact with the ground. It may be debatable whether rornotto classify 7

the seas actual vehicles, but since they were the first instance of unmanned aerial warfare, and apercus or to the century of unmanned aerial warfare that would follow, it’s an important event to note. Payload: -11-14kg.

Figure: 1.8 Austrian balloons 1.3.2. 1916 – World War 1 – Hewitt-Sperry, the first unmanned aircraft. The first pilotless aircrafts were built during World War 1. In 1916, the Hewitt-Sperry Automatic Airplane successfully flew, demonstrating that unmanned aircraft flights were possible. The Hewitt-Sperry was controlled through gyroscopes. It was intended to act as a flying bomb.

Figure: 1.9 Hewitt-Sperry

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1.3.3. 1918 – US Army Develops Kettering Bug Following a demonstration of the Hewitt-Sperry the previous year, the US Army commissioned the development of the Kettering Bug. The unmanned Kettering Bug was also intended to act as a flying bomb, but was much more successful, with the ability to hit targets 40 miles (64 kilometres) away. 1.3.4. 1930 – US Navy creates radio-controlled aerial aircraft In the early 1930s, the US Navy began developing the first unmanned aircraft systems that were radio-controlled. They successfully created the Curtiss N2C-2 drone in 1937. The Curtiss N2C-2 drone was radio controlled from a nearby piloted aircraft. 1.3.5. 1940 – Radio plane OQ2 – The first large-scale UAV production

Figure:1.10 Radio plane OQ2 Reginald Denny and his Radioplane Company won a US Army contract to mass produce their radio-controlled aircraft system. The Radioplane OQ2 UAV was manufactured for use in World War 2. Fifteen thousand of the drones were built for the army. 1.3.6. 1973 – Mastiff UAV – Unpiloted surveillance vehicle In 1973, Israel developed a series of unmanned aircrafts intended specifically for surveillance and scouting. The surveillance drones were called the Mastiff and the IAA Scout. 1.3.7. 1982 – Battlefield UAVs In 1982, Israel’s Air Force used UAVs as a major component of their battle with Syria’s Air Force. The implementation was extremely successful, and because the vehicles were unmanned, Israeli casualties were kept to a minimum while they successfully won the battle. This changed the world’s perspective on the legitimacy of unmanned aircraft systems and how dependable the technology was. 9

1.3.8. 1985 – US – large-scale UAV development In 1985, the United States Military launches a large-scale UAV development program, intended to research and develop the technology further. 1.3.9. 1986 – RQ2 Pioneer Reconnaissance drone In 1986, United States and Israel form a joint effort to produce the RQ2 Pioneer Reconnaissance drone.

Figure: 1.11 RQ2 Pioneer Reconnaissance drone 1.3.10. 2006 – UAVs permitted in US civilian airspace. A year after Hurricane Katrina, the U.S. Federal Aviation Administration authorizes the use of UAV drones in civilian airspace for the first time, in order to search for survivors of disasters. The Predator drone of the time, equipped with an infrared camera, was capable of detecting human heat signatures from a height as far as 10,000 feet. 1.3.11. 2010 – Parrot AR Drone is released.

Figure: 1.12 Parrot AR Drone

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The Parrot AR Drone was the first smartphone-controlled quadcopter UAV available for consumers. It was first revealed at the International CES 2010 in Las Vegas. Also implemented for the first time, was an IOS application that acted as a control system. The AR Drone was 22 inches (57cm) in diameter, a size that was manageable for consumer use. 1.3.12. 2013 – DJI releases the Phantom 1 UAV. The release of DJI’s Phantom 1 quadcopter drone, followed by the Phantom 2, saw camera equipped UAVs enter the market for the first time. The Phantom 1 was able to mount a Go Pro, opening a whole new world of aerial photography and cinematography possibilities to hobbyists. DJI’s UAV products quickly gained popularity and made their way into the mainstream market.

Figure: 1.13 Phantom 1 UAV 1.3.13. 2013 – Amazon Drone Delivery. Amazon’s CEO, Jeff Bezos, states that he plans to implement delivery drones to send products to Amazon customers. 1.3.14. 2014 – Film and TV Use.

Figure: 1.14 Use in Film Industry 11

FAA permits Hollywood film and TV production companies to use drones on set. At this point, prosumer drones with high-quality cameras are already on the market. In addition, high-quality professional drones that are capable of mounting expensive industry-standard cinema cameras are available from companies such as DJI. The UAV world still continues to change – and at a much faster pace than ever before. As technology advances, the capabilities and possibilities of drones will expand significantly. Recent months have seen the SELFLY drone camera case and the bee drone UAV take flight. Innovation is everywhere, and the sky is truly the limit.

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Chapter 2 Literature Review 2.1 REVIEW OF LITERATURE: [1] Ravi Jangir et al., analysed that between the single rotor and co-axial rotor drone it can be said that co-axial design provides increased payload for the same engine power, torque (rotational force) exerted on the helicopter fuselage is no longer a problem. Coaxial rotors avoid the effects of dissymmetry of lift through the use of two rotors turning in opposite directions, causing blades to advance on either side at the same time. And comparing to the analysis reports we can say that for the given co-axial multipurpose drone which is of the size 8m x 8m x 3m. The rotor distance of 400mm is optimum at 450rpm to provide us with a payload capacity of 3000kg as compared to the the similar single rotor drone.

[2] B.Theys et al., discusses the effects of propeller configuration on the propulsion system efficiency of a multi-rotor. Five design choices are studied. A pusher configuration proves to be preferable in terms of efficiency in hover conditions. An increase of 2 to 4% in efficiency is measured. This increase is small, however, and requires a taller more complicated integration of the landing gear, resulting in more weight. A three-bladed variant of the tested propeller results in a lower efficiency in the order of 2 to 6% but can be beneficial to reduce noise and risk due to its lower required rpm. Tests with three different arms on which the propulsion system is mounted, show that a thin rectangular arm is more efficient compared to a slightly thicker but aerodynamically shaped arm and can improve efficiency compared to a thick arm with 4 to 8%. The difference between the three arms becomes less pronounced for higher disk loadings. At low disk loadings, the propulsion system setup with a coaxial set of propellers is less efficient compared to the setup with a single propeller [3] Yuvaraj.S, C.J. Thomas Renald et al., analysed that the newly designed Propeller blade with Five blade propulsion system has better efficiency and uniform thrust factors.The Drone with five-blade propeller operates quieter and generates lower amplitude vibrations. Hence there is an improvement in stability of the drone. As the number of blade increases, the diameter required for producing same level of thrust reduces.

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The Diameterhas a vast consequenceon Drone’sperformance. If it catches more incoming fluid and distributes its power and thrust on a larger fluid volumethen, the larger propellerhaving higher efficiency. The lifting surfaces, which results in sailplanes which is having large span but slender wings.4similarly the outcome can be shown. The efficiency of the number of blade sare more effective. As it distributes its power and thrust more evenly in its wake, there are slightly better to perform propeller with more bladder. Thenarrow blades with reduced chord length, while for given power or thrust. so practical limits have to be considered here.When decreasing the diameter of the propeller, the chord length can be increased, to keep the power consumption constant. But reduction of the propeller’s diameter is usually a bad idea in terms of efficiency, as long as the tip Mach number or tip cavitation is not an issue. The newly designed Propeller blade with Five blade propulsion system has better efficiency and uniform thrust factors.The Drone with five-blade propeller operates quieter and generates lower amplitude vibrations. Hence there is an improvement in stability of the drone. As the number of blade increases, the diameter required for producing same level of thrust reduces. [4] Endrowednes Kuantama et al., observed in relation to quadcopter body frame model, that propeller can be categorized into propeller with ducted and without ducted. This study present differences between those two using CFD (Computational Fluid Dynamics) method. Both categories utilize two blade-propeller with diameter of 406 (mm). Propeller rotation generates acceleration per time unit on the volume of air. Based on the behavior of generated air velocity, ducted propeller can be modeled into three versions. The generated thrust and performance on each model were calculated to determine the best model. The use of ducted propeller increases the total weight of quadcopter and also total thrust. The influence of this modeling were analyzed in detail with variation of angular velocity propeller from 1000 (rpm) to 9000 (rpm). Besides the distance between propeller tip and ducted barrier, the size of ducted is also an important part in thrust optimization and total weight minimization of quadcopter. In this study, the type of material used was not taken into account but from the surface area ducted it can be seen that the α type is lighter than the other ducted type of modeling. [5] Mathew Thomas et al., analysed that the required light airframe feasibility

UAV(Quadcopter) design is fabricated using carbon fiber of crash resistibility and made it to

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fly successfully. This Structural Analysis of the carbon fibre leads to the following conclusions: - • Vibration got reduced when compared to the plastic uav. There is no effet to the rotors propellers and othr electrical components by using this design. The strength and resistance capacity is increased. [6] Ali Bin Junaid et al., observed that a design and implementation of an over-actuated quadcopter with dual-axis tilting rotors. The CAD model was developed following the manufacturing of the system using rapid prototyping in order to minimize the manufacturing time and cost. The modeling and simulation of the over-actuated system allowed observing the behavior of the platform using different control inputs. The flight test results in outdoor conditions show satisfactory performance of the developed platform. The experiments were performed to observe and compare the capability of over-actuated configuration against conventional configuration which showed that the proposed platform performs better when it comes to flying along corners and between adjacent obstacles, and gives better maneuverability compared to conventional quadcopter. [7] Dan CRACIUN et al., analysed that the quadcopter body frame which was designed with Solidworks software has a good rigidity and the size also compatible with the specification of rotor propeller used. The rigidity of plastic-based frame with a weight of 560 (gram) has a maximum displacement of 3.3 (mm) for 52 (N) thrust on the wing frame part. With the rotor specification stated in this research, 560 (mm) distance between rotor and 406x127 (mm) propeller, the maximum angular velocity that can be used is 7680 (rpm) which generated 21 (N) thrust. This is because the airflow produced between two propellers must not interplay, thus generate a stable thrust and not causing vibration on the body frame. For the initial analysis, the generated thrust can be calculated using momentum and fluid dynamic theory. However, to get a better result, an experimental method is preferable. [8] Rene’L Mouille et al observed that to optimise lift of the blade without excessively increasing the drag, it is advantageous if the maximum relative thickness of the root profile is atleast equal to 9% and at the most equal to 13% of the length of the chord of said root profile. Similarly, to optimise the drag, the maximum relative thickness of the end profile is atleast equal to 6% and at the most equal to 9% of the length of the chord of the end profile. [9] Ganesh Redde, Prasad kulkarni, Prakash In this study, the focus was on the use of proposed drone for industrial works more specifically for multi-purpose application as per the 15

customer requirement. The design considerations were explicitly for generic drone uses such as light and heavy-duty applications, entertainment, courier services etc. I have tried to keep design as simple as possible so that manufacturing processes used will not cost much. The proposed drone is user friendly and also easy to understand. In this paper I have tried to reduce (approximately 30 %) the manufacturing cost of the frame. To use it for more heavy applications, I have combined two quad copters in one octocopter. An acceptable safety factor of 3 was observed during static analysis of designed octocopter. This safety factor is very much acceptable considering its manufacturability and the applications for which it was initially targeted [10] Faiyaz Ahmed present mechanical structure and describe all parts of quadcopter which gives good solution for a quadrotor design when its dimension and cost are the main constraints. The quadcopter configuration has a greater stability as compared to the other configurations and it is able to hover close to its target, unlike its other counter parts. This type of project plays a major role in civilized countries for surveillance of the terrestrial areas, film industries, managing traffics and city planning. The core intention of this work is to study complete designing and manufacturing process of quadcopter from the engineering prospective and improving their balance and stability system. As per future aspects, there is advancement in technology of quadcopters dramatically. In recent days, a company like Boeing, Airbus, DJ Innovations, Parrot, Walkera, Blade and Heli-Max are working on some projects like Bell Boeing Quad TiltRotor, AeroQuad and ArduCopter, Parrot AR. Drone, Nixie, Zano (drone), Lily Camera drone, etc [11] Naveen kumar, tested the propeller and propeller design was carried out by importing the airfoil section onto the datum planes. Using the ANSYS workbench software, analysis of the Propeller and Frame were carried out and the results obtained were within the limits. For analyzing the propeller structure ANSYS Workbench is the most efficient software. To achieve optimal aerodynamic performance, the only option would be to design a propeller to suit the specific application of high thrust upward propulsion and can improve the current flight time of Octocopter drone for the heavy applications. After checking the propellers analysis and frame we have to check correlation of whole system and effect of air pressure while lifting the Octocopter drone. [12] L.Chilson studied additive manufacturing and found out is an extremely effective tool for quadcopter enthusiasts designing their own vehicles. 3D printing is ideal due to its

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affordability, the freedom it grants designers to readily customize their unit, the flexibility and durability of the materials used in the 3D printing process, and its environmental friendliness. Although ABS plastic is superior in strength and durability to PLA, the latter was found to present fewer complications during the printing process and therefore to be preferable for inexperienced designers. Moreover, quadcopters were determined to be a superior alternative in this case to other multi rotor helicopters, which suffer from issues in stability, maneuverability, and battery life. When designing a frame, stress tests are imperative to perform in order to determine the location of structural weak points where vibration and mechanical stress must be mitigated. Other hobbyists might improve the design herein developed by foregoing the purchase of a flight transmitter and instead operating it directly from a computer, further reducing the device’s cost. A camera might also be added, which, though raising the cost of the quadcopter, would allow it to be flown at a greater distance from its operator.

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Chapter 3 Design of Aerial System 3.0 Classification According to Size: 3.0.1. Very small UAVs The very small UAV class applies to UAVs with dimensions ranging from the size of a large insect to 30-50 cm long. The insect-like UAVs, with flapping or rotary wings, are a popular micro design. They are extremely small in size, are very light weight, and can be used for spying and biological warfare. .

Figure: 3.1 Very small Size 3.0.2 Small UAVs The Small UAV class (which also called sometimes mini-UAV) applies to UAVs that have at least one dimension greater than 50 cm and no larger than 2 meters. Many of the designs in this category are based on the fixed-wing model.

Figure: 3.2 Small Size

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3.0.3 Medium UAVs The medium UAV class applies to UAVs that are too heavy to be carried by one person but are still smaller than a light aircraft. They usually have a wingspan of about 5-10 m.

Figure: 3.3 Medium Size 3.0,4 Large UAVs The large UAV class applies to the large UAVs used mainly for combat operations by the military.

Figure: 3.4 Large Size

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3.1 Classification According to Range and Endurance 3.1.1 Very low-cost, close range UAVs: This class includes UAVs that have a range of 5 km, endurance time of 20 to 45 minutes, and cost of about $10,000 (2012 estimate). Examples of UAVs in this class are the Raven and Dragon Eye. UAVs in this class are very close to model airplanes. 3.1.2 Close range UAVs: This class includes UAVs that have a range of 50 km and endurance time of 1 to 6 hours. They are usually used for reconnaissance and surveillance tasks. 3.1.3 Short range UAVs: This class includes UAVs that have a range of 150 km or longer and endurance times of 8 to 12 hours. Like the close-range UAV, they are mainly utilized for reconnaissance and surveillance purposes. 3.1.4 Mid-range UAVs: The mid-range class includes UAVs that have super high speed and a working radius of 650 km. They are also used for reconnaissance and surveillance purposes in addition to gathering meteorological data.

3.2 Different types of drones: Classification of the drones may sound impossible, due to the fact there are a lot of different models, with different features, sizes, and price. The only way we can classify them is by size. 3.2.1NANO AND MINI DRONES Nano drones are the smallest and they usually have the same dimensions as insects. On the other side, mini drones can reach up to 50cm in length and they have more powerful electric motors and better features than Nano drones. In general, models from both categories are used by the military, in spying and smaller tasks, due to the fact they can be easily maneuverer and they can reach remote locations.

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Figure: 3.5 Nano Type Drone 3.2.2. DRONES WITH SMALL SIZES Drones from this group have dimensions between 50 cm and 2 m. They don’t have powerful motors so they must be thrown into the air, in order to start flying. These products are also very popular on the market because they have great features and they are more affordable than bigger drones. These drones are also the most common type of drones available to average customers. These drones are also the most common type of drones available to average customers. Simply said, most drones that you can see on the market are members of this group. All of them have a radius of 5 km and they can fly between 20 and 40 minutes.

Figure: 3.6 Small Size Drone

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3.2.3. DRONES WITH MEDIUM SIZES Every drone that has a wingspan between 5 and 10 m falls into the medium category. These drones can carry up to 200 kg of weight and they have powerful motors. In addition, a single person cannot carry a drone from this group, so they are not a common choice of ordinary people. These drones are usually used for transporting goods, to remote locations and by the military. Keep in mind that these drones are still smaller and lighter than other light aircraft. They can fly up to 50 km and their flying time can be long as 6 hours.

Figure: 3.7 Medium Size Drone An FPV Drone Frame is like a suit of armour for all of the sensitive electrical components that constitute a quadcopter. It is essential that a frame is as durable and rugged as possible, while still accommodating to the needs of the pilot without hindering the flying experience and the inevitable maintenance that will ensue.

Size Matters Each frame has a designated size class, based upon the longest distance from motor to motor measured in millimetres, typically taken by measuring diagonally across the frame. A frame measuring less than 150mm motor-to-motor is categorized as a micro. A frame larger than 150mm motor-to-motor is considered a mini. When measuring an unconventional multicopper frame, such as a hexacopter or tricopter, the size will always be given by the greatest motor-to-motor distance.

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3.3 Design Mechanics:

Figure: 3.8 Frame Size View

3.3.1 Naming system of a drone frame The quadcopter is the most popular design for several reasons, namely mechanical simplicity, quantity of motors and ESC’s required for flight and their compact size. There are other forms of multicopters that although unconventional are perfect for certain applications, or even simply the whimsy of their unique structure. Multicopters are simply named with a numeral prefix (e.g. Bi, Tri, Quad) followed by “copter”.

Figure: 3.9 Type of Frame

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3.4DRONE FRAME STYLE: 3.4.1 TRUE X The true X is shaped as it sounds, an X geometry to which a motor is mounted to each end of the arms. The perpendicular distance between the centre of each motor is equal, therefore giving the quadcopter the same level of stability on all axis.

Figure: 3.10 True X

3.4.2 Wide X A wide X has its arms splayed outward to the side. The wide X geometry is more common in freestyle frames, this is because more central space is often required to mount an action camera and battery on top of the frame.

Figure: 3.11 Wide X

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3.4.3 Vertical Arms Vertical arms rotate the orientation of the arms to produce as small of a surface area as possible to minimize drag. Durability is not usually compromised as the arm may still maintain width, however, construction of the frame is often more complex than standard horizontal frames.

Figure: 3.12 Vertical Arms 3.4.4 Plus A plus frame has the same footprint as a X frame that has been turned 45°. A plus frame can be seen as advantageous in that each motor is responsible for rotational movement in only one axis, theoretically meaning finer control is possible. Although, plus frames are more prone to breakage due to most impacts involving a forceful strike to the front arm only.

Figure: 3.13 Plus type

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3.4.5 HX The HX is a newer variant of the H. Instead of placing the arms at the tip and tail of the carriage, a true X, wide X or stretch X configuration is applied, most often wide or true X

Figure: 3.14 HX Type

3.5Drone Components:

Figure: 3.15 Drone’s Component

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3.5.1. Standard Propellers The propellers are usually located at the front of the drone/quadcopter. There are very many variations in terms of size and material used in the manufacture of propellers. Most of them are made of plastic especially for the smaller drones but the more expensive ones are made of carbon fiber. Propellers are still being developed and technological research is still ongoing to create more efficient propellers for both small and big drones. Propellers are responsible for the direction and motion of the drone. It is therefore important to ensure that each of the propellers is in good condition before taking your drone out for flight. A faulty propeller means impaired flight for the drone and hence an accident. You can also carry an extra set of propellers just in case you notice some damage that was not there before.

3.5.2. Pusher Propellers Pusher propellers are the ones responsible for the forward and backward thrust of the drone during flight. As the name suggest, the pusher propellers will determine the direction the drone takes either forward or backward. They are normally located at the back of the drone. They work by cancelling out the motor torques of the drone during stationary flight leading to forward or backward thrust. Just like the standard propellers, the pusher propellers can also be made of plastic or carbon fibre depending on the quality. The more expensive ones are usually made of carbon fibre. There are different sizes depending on the size of the drone. Some drones provide for pusher prop guards that will help protect your propellers in the event of an unplanned crash. Always ensure you inspect your pusher propellers before flight as this will determine the efficiency pf the flight.

3.5.3. Brushless Motors All drones being manufactured lately use the brushless motors that are considered to be more efficient in terms of performance and operation as opposed to the brushed motors. The design of the motor is as important as the drone itself. This is because an efficient motor means you will be able to save on costs of purchase and maintenance costs. In addition to that, you will also save on battery life which contributes to longer flight time when flying your drone. Currently, the drone motor design market is pretty exciting as companies try to outdo each other in coming up with the most efficient and best developed motors. The latest in the market is the DJI Inspire 1 which was launched recently. This offers more efficient performance and saves on battery life. It is also relatively quiet and does not produce a lot of unnecessary noises. 27

Type of Brushless motor:

Figure: 3.16 Different types of Motor 3.5.4. Landing Gear Some drones come with helicopter-style landing gears that help in landing the drone. Drones which require high ground clearance during landing will require a modified landing gear to allow it to land safely on the ground. In addition to that, delivery drones that carry parcels or items may need to have a spacious landing gear due to the space required to hold the items as 28

it touches the ground. However, not all drones require a landing gear. Some smaller drones will work perfectly fine without a landing gear and will land safely on their bellies once they touch the ground. Most drones that fly longer and cover longer distances have fixed landing gears. In some cases, the landing gear may turn out to be an impediment to the 360 degrees view of the environment especially for a camera drone. Landing gears also increase the safety of the drone.

3.5.5. Electronic Speed Controllers An electronic sped controller (ESC) is an electric circuit whose main responsibility is to monitor and vary the speed of the drone during flight. It is also responsible for the direction of flight and variations in brakes of the drone. The ESC is also responsible for the conversion of DC battery power to AC power to propel the brushless motors. Modern drones depend entirely on the ESC for all their flight needs and for performance. More and more companies are coming up with better performing ESC that reduce power needs and increase performance, the latest one being the DJI Inspire 1 ESC. The ESC is mainly located inside the mainframe of the drone. It is unlikely that you will need to do anything or make any change on the ESC but in case you need to make any changes, you can locate it inside the mainframe of the drone.

3.5.6. Flight Controller The flight controller is basically the motherboard of the drone. It is responsible for all the commands that are issued to the drone by the pilot. It interprets input from the receiver, the GPS Module, the battery monitor and the onboard sensors. The flight controller is also responsible for the regulation of the motor speeds through the ESC and for the steering of the drone. Any commands such as triggering of the camera, controlling the autopilot mode and other autonomous functions are controlled by the flight controller. Users will most likely not be required to make any alterations to the flight controller as this may often affect the performance of the drone.

3.5.7. The Receiver The receiver is the unit responsible for the reception of the radio signals sent to the drone through the controller. The minimum number of channels that are needed to control a drone are usually 4. However, it is recommended that a provision of 5 channels be made available.

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There are very many different types of receivers in the market and all of them can be used when making a drone.

3.5.8. The Transmitter The transmitter is the unit responsible for the transmission of the radio signals from the controller to the drone to issue commands of flight and directions. Just like the receiver, the transmitter needs to have 4 channels for a drone but 5 is usually recommended. Different types of receivers are available in the market for drone manufacturers to choose from. The receiver and the transmitter must use a single radio signal in order to communicate to the drone during flight. Each radio signal has a standard code that helps in differentiating the signal from other radio signals in the air.

3.5.9. GPS Module The GPS module is responsible for the provision of the drone longitude, latitude and elevation points. It is a very important component of the drone. Without the GPS module, drones would not be as important as they are today. The modules helps drone navigate longer distances and capture details of specific locations on land. The GPS module also help in returning the drone safely “home” even without navigation using the FPV. In most modern drones, the GPS module helps in returning the drone safe to the controller in case it loses connection to the controller. This helps in keeping the drone safe.

3.5.10. Battery The battery is the part of the drone that makes all actions and reactions possible. Without the battery, the drone would have no power and would therefore not be able to fly. Different drones have different battery requirements. Smaller drones may need smaller batteries due to the limited power needs. Bigger drones, on the other hand, may require a bigger battery with a larger capacity to allow it to power all the functions of the drone. There is a battery monitor on the drone that helps in providing battery information to the pilot to monitor the performance of the battery.

3.5.11. Camera Some drones come with an inbuilt camera while others have a detachable camera. The camera helps in taking photos and images from above which forms an important use of 30

drones. There are different camera types and qualities in the market and a variety to choose from

3.6Drone mechanics: 3.6.1 Importance of How A Quadcopter Works and Flies: 1. With a small bit of experience, flying a quadcopter becomes automatic. You move the sticks on the Remote Controller Ground Station which send the quadcopter in whichever direction you want it to fly. We don’t need to think about what the motors or propellers are doing. 2. Now supposing your quadcopter wasn’t flying correctly. Maybe it is pulling in one direction or not hovering smoothly. Well, understanding how a quadcopter works and flies will help you locate the issue with a motor or propeller, especially if a visual inspection does not show a fault. 3. When you understand quadcopter propeller design and motor thrust, you can make changes to your quadcopter such as removing the camera and installing another payload such as a Time-of-Flight or a Lidar sensor. 4. Flying with a different payload will have an effect on the control, flight and balance of the drone. A different payload will then require different quadcopter motor thrust. 3.6.2 Vertical motion: 1. In order for a quadcopter to rise into the air, a force must be created, which equals or exceeds the force of gravity. This is the basic idea behind aircraft lift, which comes down to controlling the upward and downward force. 2. Now, quadcopters use motor design and propeller direction for propulsion to basically control the force of gravity against the quadcopter. 3. The spinning of the quadcopter propeller blades push air down. All forces come in pairs (Newton’s Third Law), which means for every action force there is an equal (in size) and opposite (in direction) reaction force. Therefore, as the rotor pushes down on the air, the air pushes up on the rotor. The faster the rotors spin, the greater the lift and vice-versa. 4. Now, a drone can do three things in the vertical plane: hover, climb, or descend.

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5. Hover Still – To hover, the net thrust of the four rotors push the drone up and must be exactly equal to the gravitational force pulling it down. 6. Climb Ascend – By increasing the thrust (speed) of the four quadcopter rotors so that the upward force is greater than the weight and pull of gravity. 7. Vertical Descend – Dropping back down requires doing the exact opposite of the climb. Decrease the rotor thrust (speed) so the net force is downward. 3.6.3 Turning rotation: 1. Let's say we have a hovering drone pointed north and you want to rotate it to face east. How do you accomplish this by changing the power to the four rotors? Before answering, here is a diagram of the rotors (viewed from above) labelled 1 through 4.

Figure: 3.17 Turning Rotation 2. In this configuration, the red rotors are rotating counter-clockwise and the green ones are rotating clockwise. With the two sets of rotors rotating in opposite directions, the total angular momentum is zero. . If there is no torque on the system (the system here being the drone), then the total angular momentum must remain constant . Let’s assume that the red counter-clockwise rotors have a positive angular momentum and the green clockwise rotors have a negative angular momentum. And now assign each rotor a value of +2, +2, -2, -2, which adds up to zero. 32

3. Let's say we want to rotate the drone to the right. Suppose we decrease the angular velocity of rotor 1 such that now it has an angular momentum of -1 instead of -2. If nothing else happened, the total angular momentum of the drone would now be +1. Of course, that can't happen. So the drone rotates clockwise so that the body of the drone has an angular momentum of -1. That’s how the drone rotates. 4. Decreasing the spin of rotor 1 did indeed cause the drone to rotate, but it also decreased the thrust from rotor 1. Now the net upward force does not equal the gravitational force, and the drone descends. But now the thrust forces aren't balanced, so the drone tips downward in the direction of rotor. To rotate the drone without creating all those other problems, decrease the spin of rotor 1 and 3 and increase the spin for rotors 2 and 4. 5. The angular momentum of the rotors still doesn't add up to zero, so the drone body must rotate. But the total force remains equal to the gravitational force and the drone continues to hover. Since the lower thrust rotors are diagonally opposite from each other, the drone can still stay balanced. 6. Forwards and Sideways 7. In order to fly forward, we need a forward component of thrust from the rotors. Here is a side view (with forces) of a drone moving at a constant speed.

3.6.4 How do we get the drone into this position? 1. We could increase the rotation rate of rotors 3 and 4 (the rear ones) and decrease the rate of rotors 1 and 2. The total thrust force will remain equal to the weight, so the drone will stay at the same vertical level. Also, since one of the rear rotors is spinning counter-clockwise and the other clockwise, the increased rotation of those rotors will still produce zero angular momentum. The same holds true for the front rotors, and so the drone does not rotate. However, the greater force in the back of the drone means it 33

will tilt forward. Now a slight increase in thrust for all rotors will produce a net thrust force that has a component to balance the weight along with a forward motion component. 3.6.5 YAW, ROLL, PITCH:

Figure: 3.18 Directional Movement 3.6.5.1 “Yaw” refers to the direction the front of your drone (or even a plane or car) is facing when rotating either clockwise or counter-clockwise (or left and right if you prefer) on its vertical axis.

Figure: 3.19 Yaw 3.6.5.2 Roll - This moves the drone to the sides, causing it to “roll.” However, it does notcause the drone to change its altitude position. These “rolls” cause the aircraft to move to the right and the left on its horizontal axis.

Figure: 3.20 Roll 34

3.6.5.3 Pitch - The second dimension an aircraft can move in is called “pitch.” The pitch means the drone tilts upwards or downwards based on its orientation and the location of its nose. A downwards tilt will move the aircraft (drone in this case) in a forwards motion, while an upwards tilt will move it backwards.

Figure: 3.21 Pitch

3.7Motor Thrust Calculation: Static Thrust Static Thrust is defined as the amount of thrust produced by the propeller which is positioned stationary to Earth .This calculation is particularly important because quad rotor is more likely to perform at low speed relative to Earth. Also, it is important to note that the final calculations of static thrust are estimated and not actual values. In order to calculate the thrust, we first calculate the power. Power transmitted by the motor to the propeller in terms of rpm. Power is in Watts, and rpm is in thousands. The next step is to determine the thrust produced by a propeller. Thrust based on momentum theory:

T= 3.14*D*D*ρ*V* ΔV 4 T – Thrust in [N] D – Propeller diameter in [m] V – Velocity of air at the propeller in [m/s] ΔV – Velocity of air accelerated by the propeller [m/s] ρ – Density of air [1.225 kg/m3]

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3.8Comparision of 2 different type of frame : HX & TRUE X:

Figure: 3.22 Comparisiion of two Frame In this comparision , we are trying to compare the 2 totally different frae structure and tries to found out the best out of 2. We have taken these two frames into the consideration because these two frames posses most of the feature with in a single frame. 36

This is the dimansional comparision where we can clearly see that, at nearly same dimesnion HX provide the more centre spacing and better stucture that resistance to many mechanical stresses. Here HX frame structure is selceted for futhre work progress.

Figure: 3.23 Different Views of Frame 37

Chapter 4 FEM Analysis 4.1Meshing: Mesh generation is the practice of creating a mesh, a subdivision of a continuous geometric space into discrete geometric and topological cells. Often these cells form a simplicial complex. Usually the cells partition the geometric input domain. Mesh cells are used as discrete local approximations of the larger domain. Meshes are created by computer algorithms, often with human guidance through a GUI, depending on the complexity of the domain and the type of mesh desired. The goal is to create a mesh that accurately captures the input domain geometry, with high-quality (well-shaped) cells, and without so many cells as to make subsequent calculations intractable. The mesh should also be fine (have small elements) in areas that are important for the subsequent calculations.

Figure: 4.1 Meshing Introduction Meshes are used for rendering to a computer screen and for physical simulation such as finite element analysis or computational fluid dynamics. Meshes are composed of simple cells like triangles because, e.g., we know how to perform operations such as finite element calculations (engineering) or ray tracing (computer graphics) on triangles, but we do not know how to perform these operations directly on complicated spaces and shapes such as a roadway bridge. We can simulate the strength of the bridge, or draw it on a computer screen, by performing calculations on each triangle and calculating the interactions between triangles. A major distinction is between structured and unstructured meshing. In structured meshing the mesh is a regular lattice, such as an array, with implied connectivity between elements. In 38

unstructured meshing, elements may be connected to each other in irregular patterns, and more complicated domains can be captured. This page is primarily about unstructured meshes. While a mesh may be a triangulation, the process of meshing is distinguished from point set triangulation in that meshing includes the freedom to add vertices not present in the input. "Facetting" (triangulating) CAD models for drafting has the same freedom to add vertices, but the goal is to represent the shape accurately using as few triangles as possible and the shape of individual triangles is not important. Computer graphics renderings of textures and realistic lighting conditions use meshes instead. Many mesh generation software is coupled to a CAD system defining its input, and simulation software for taking its output. The input can vary greatly but common forms are Solid modelling, Geometric modelling, NURBS, B-rep, STL or a point cloud. The terms "mesh generation," "grid generation," "meshing," " and "gridding," are often used interchangeably, although strictly speaking the latter two are broader and encompass mesh improvement: changing the mesh with the goal of increasing the speed or accuracy of the numerical calculations that will be performed over it. In computer graphics rendering, and mathematics, a mesh is sometimes referred to as a tessellation. Mesh faces (cells, entities) have different names depending on their dimension and the context in which the mesh will be used. In finite elements, the highest-dimensional mesh entities are called "elements," "edges" are 1D and "nodes" are 0D. If the elements are 3D, then the 2D entities are "faces." In computational geometry, the 0D points are called vertices. Tetrahedra are often abbreviated as "tets"; triangles are "tris", quadrilaterals are "quads" and hexahedra (topological cubes) are "hexes."

4.2 Techniques: Many meshing techniques are built on the principles of the Delaunay triangulation, together with rules for adding vertices, such as Ruppert's algorithm. A distinguishing feature is that an initial coarse mesh of the entire space is formed, then vertices and triangles are added. In contrast, advancing front algorithms start from the domain boundary, and add elements incrementally filling up the interior. Hybrid techniques do both. A special class of advancing front techniques creates thin boundary layers of elements for fluid flow. In structured mesh generation the entire mesh is a lattice graph, such as a regular grid of squares. Structured mesh generation for regular grids and is an entire field itself, with mathematical techniques applied to ensure high-polynomial-order grid lines follow the solution space smoothly and 39

accurately. In block-structured meshing, the domain is divided into large subregions, each of which is a structured mesh. Some direct methods start with a block-structured mesh and then move the mesh to conform to the input; see Automatic Hex-Mesh Generation based on polycubes. Another direct method is to cut the structured cells by the domain boundary; see sculpt based on Marching cubes. Some types of meshes are much more difficult to create than others. Simplicial meshes tend to be easier than cubical meshes. An important category is generating a hex mesh conforming to a fixed quad surface mesh; a research subarea is studying the existence and generation of meshes of specific small configurations, such as the tetragonal trapezohedron. Because of the difficulty of this problem, the existence of combinatorial hex meshes has been studied apart from the problem of generating good geometric realizations. While known algorithms generate simplicial meshes with guaranteed minimum quality, such guarantees are rare for cubical meshes, and many popular implementations generate inverted (inside-out) hexes from some inputs. Meshes are often created in serial on workstations, even when subsequent calculations over the mesh will be done in parallel on super-computers. This is both because of the limitation that most mesh generators are interactive, and because mesh generation runtime is typically insignificant compared to solver time. However, if the mesh is too large to fit in the memory of a single serial machine, or the mesh must be changed (adapted) during the simulation, meshing is done in parallel.

4.3 What Are the Different Element Types. As we saw earlier, there are four different 3D element types — texts, bricks, prisms, and pyramids:

Figure: 4.2 Different Element Shapes These four elements can be used, in various combinations, to mesh any 3D model. (For 2D models, you have triangular and quadrilateral elements available. We won’t discuss 2D very much here, since it is a logical subset of 3D that doesn’t require much extra

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explanation.) What we haven’t spoken in-depth about yet is why you would want to use these various elements.

4.4 Why and When to Use the Elements. Tetrahedral elements are the default element type for most physics within COMSOL Multiphysics. Tetrahedra are also known as a simplex, which simply means that any 3D volume, regardless of shape or topology, can be meshed with tets. They are also the only kind of elements that can be used with adaptive mesh refinement. For these reasons, tets can usually be your first choice. The other three element types (bricks, prisms, and pyramids) should be used only when it is motivated to do so. It is first worth noting that these elements will not always be able to mesh a particular geometry. The meshing algorithm usually requires some more user input to create such a mesh, so before going through this effort, you need to ask yourself if it is motivated. Here, we will talk about the motivations behind using brick and prism elements. The pyramids are only used when creating a transition in the mesh between bricks and tets. It is worth giving a bit of historical context. The mathematics behind the finite element method was developed well before the first electronic computers. The first computers to run finite element programs were full of vacuum tubes and hand-wired circuitry, and although the invention of transistors led to huge improvements, even the supercomputers from 25 years ago had about the same clock speed as today’s fashion accessories. Some of the first finite element problems solved were in the area of structural mechanics, and the early programs were written for computers with very little memory. Thus, firstorder elements (often with special integration schemes) were used to save memory and clock cycles. However, first-order tetrahedral elements have significant issues for structural mechanics problems, whereas first-order bricks can give accurate results. As a legacy of these older codes, many structural engineers will still prefer bricks over tets. In fact, the second order tetrahedral element used for structural mechanics problems in the COMSOL software will give accurate results, albeit with different memory requirements and solution times from brick elements. The primary motivation in COMSOL Multiphysics for using brick and prism elements is that they can significantly reduce the number of elements in the mesh. These elements can have very high aspect ratios (the ratio of longest to shortest edge), whereas the algorithm 41

used to create a tet mesh will try to keep the aspect ratio close to unity. It is reasonable to use high aspect ratio brick and prism elements when you know that the solution varies gradually in certain directions or if you are not very interested in accurate results in those regions because you already know the interesting results are elsewhere in the model. Meshing Example 1: Wheel Rim Consider the example of a wheel rim, shown below.

Figure: 4.3 Meshing on Tyre Rim The mesh on the left is composed only of tets, while the mesh on the right has tets (green), bricks (blue), and prisms (pink), as well as pyramids to transition between these elements. The mixed mesh uses smaller tets around the holes and corners, where we expect higher stresses. Bricks and prisms are used in the spokes and around the rim. Neither the rim nor the spokes will carry peak stresses (at least under a static load), and we can safely assume a relatively slow variation of the stresses in these regions. The tet mesh has about 145,000 elements and around 730,000 degrees of freedom. The mixed mesh has close to 78,000 elements and roughly 414,000 degrees of freedom, taking about half as much time and memory to solve. The mixed mesh does take significant user interaction to set up, while the tet mesh requires essentially no user effort. Note that there is not a direct relationship between degrees of freedom and memory used to solve the problem. This is because the different element types have different computational

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requirements. A second-order tet has 10 nodes per element, while a second-order brick has 27. This means that the individual element matrices are larger, and the corresponding system matrices will be denser, when using a brick mesh. The memory (and time) needed to compute a solution depends upon the number of degrees of freedom solved for, as well as the average connectivity of the nodes, and other factors. Meshing Example 2: Loaded Spring Another example is shown below. This time, it’s a structural analysis of a loaded spring. Since the deformation is quite uniform along the length of the helix of the spring, it makes sense to have a mesh that describes the overall shape and cross section, but relatively stretched elements along the length of the wire. The prism mesh has 504 elements with 9526 degrees of freedom, and the tet mesh has 3652 elements with 23,434 degrees of freedom. So although the number of elements is quite different, the number of degrees of freedom is less so.

Figure: 4.4 Meshing on Loaded Spring

4.5 Common cell shape:

Figure: 4.5 Different Cell Shape 43

4.5.1 Basic two-dimensional Cell shapes There are two types of two-dimensional cell shapes that are commonly used. These are the triangle and the quadrilateral. Computationally poor elements will have sharp internal angles or short edges or both. Triangle This cell shape consists of 3 sides and is one of the simplest types of mesh. A triangular surface mesh is always quick and easy to create. It is most common in unstructured grids. Quadrilateral This cell shape is a basic 4 sided one as shown in the figure. It is most common in structured grids. Quadrilateral elements are usually excluded from being or becoming concave. Three-dimensional

Figure: 4.6 3-D Cell Shape

4.5.2 Basic three-dimensional cell shapes The basic 3-dimensional element are the tetrahedron, quadrilateral pyramid, triangular prism, and hexahedron. They all have triangular and quadrilateral faces. Extruded 2-dimensional models may be represented entirely by the prisms and hexahedra as extruded triangles and quadrilaterals. In general, quadrilateral faces in 3-dimensions may not be perfectly planar. A nonplanar quadrilateral face can be considered a thin tetrahedral volume that is shared by two neighbouring elements.

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Tetrahedron A tetrahedron has 4 vertices, 6 edges, and is bounded by 4 triangular faces. In most cases a tetrahedral volume mesh can be generated automatically. Pyramid A quadrilateral-based pyramid has 5 vertices, 8 edges, bounded by 4 triangular and 1 quadrilateral face. These are effectively used as transition elements between square and triangular faced elements and other in hybrid meshes and grids. Triangular prism A triangular prism has 6 vertices, 9 edges, bounded by 2 triangular and 3 quadrilateral faces. The advantage with this type of layer is that it resolves boundary layer efficiently. Hexahedron A hexahedron, a topological cube, has 8 vertices, 12 edges, bounded by 6 quadrilateral faces. It is also called a hex or a brick.[1] For the same cell amount, the accuracy of solutions in hexahedral meshes is the highest. The pyramid and triangular prism zones can be considered computationally as degenerate hexahedrons, where some edges have been reduced to zero. Other degenerate forms of a hexahedron may also be represented. Advanced Cells (Polyhedron) A polyhedron (dual) element has any number of vertices, edges and faces. It usually requires more computing operations per cell due to the number of neighbours (typically 10).[2] Though this is made up for in the accuracy of the calculation.

4.6 Classification of Grid:

Structured grid

Unstructured grid

Figure: 4.7 Different type of Grid

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4.6.1 Structured grids Structured grids are identified by regular connectivity. The possible element choices are quadrilateral in 2D and hexahedra in 3D. This model is highly space efficient, since the neighbourhood relationships are defined by storage arrangement. Some other advantages of structured grid over unstructured are better convergence and higher resolution.

4.6.2 Unstructured grids An unstructured grid is identified by irregular connectivity. It cannot easily be expressed as a two-dimensional or three-dimensional array in computer memory. This allows for any possible element that a solver might be able to use. Compared to structured meshes, this model can be highly space inefficient since it calls for explicit storage of neighbourhood relationships. These grids typically employ triangles in 2D and tetrahedral in 3D.

4.6.3 Hybrid grids A hybrid grid contains a mixture of structured portions and unstructured portions. It integrates the structured meshes and the unstructured meshes in an efficient manner. Those parts of the geometry that are regular can have structured grids and those that are complex can have unstructured grids. These grids can be non-conformal which means that grid lines don’t need to match at block boundaries.

4.7 Mesh quality: A mesh is considered to have higher quality if a more accurate solution is calculated more quickly. Accuracy and speed are in tension. Decreasing the mesh size always increases the accuracy but also increases computational cost. Accuracy depends on both discretization error and solution error. For discretization error, a given mesh is a discrete approximation of the space, and so can only provide an approximate solution, even when equations are solved exactly. (In computer graphics ray tracing, the number of rays fired is another source of discretization error.) For solution error, for PDEs many iterations over the entire mesh are required. The calculation is terminated early, before the equations are solved exactly. The choice of mesh element type affects both discretization and solution error.

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Accuracy depends on both the total number of elements, and the shape of individual elements. The speed of each iteration grows (linearly) with the number of elements, and the number of iterations needed depends on the local solution value and gradient compared to the shape and size of local elements.

Solution precision A coarse mesh may provide an accurate solution if the solution is a constant, so the precision depends on the particular problem instance. One can selectively refine the mesh in areas where the solution gradients are high, thus increasing fidelity there. Accuracy, including interpolated values within an element, depends on the element type and shape.

Rate of convergence Each iteration reduces the error between the calculated and true solution. A faster rate of convergence means smaller error with fewer iterations. A mesh of inferior quality may leave out important features such as the boundary layer for fluid flow. The discretization error will be large and the rate of convergence will be impaired; the solution may not converge at all.

Grid independence A solution is considered grid-independent if the discretization and solution error are small enough given sufficient iterations. This is essential to know for comparative results. A mesh convergence study consists of refining elements and comparing the refined solutions to the coarse solutions. If further refinement (or other changes) does not significantly change the solution, the mesh is an "Independent Grid." Deciding the type of mesh Skewness based on equilateral volume If the accuracy is of the highest concern then hexahedral mesh is the most preferable one. The density of the mesh is required to be sufficiently high in order to capture all the flow features but on the same note, it should not be so high that it captures unnecessary details of the flow, thus burdening the CPU and wasting more time. Whenever a wall is present, the mesh adjacent to the wall is fine enough to resolve the boundary layer flow and generally quad, hex

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and prism cells are preferred over triangles, tetrahedrons and pyramids. Quad and Hex cells can be stretched where the flow is fully developed and one-dimensional.

Figure: 4.8 Skewness based on equilateral volume Depicts the skewness of a quadrilateral Based on the skewness, smoothness, and aspect ratio, the suitability of the mesh can be decided. Skewness The skewness of a grid is an apt indicator of the mesh quality and suitability. Large skewness compromises the accuracy of the interpolated regions. There are three methods of determining the skewness of a grid. Based on equilateral volume This method is applicable to triangles and tetrahedral only and is the default method.

Figure: 4.9 Changes in Terms of Volume 4.7.1 Based on the deviation from normalized equilateral angle This method applies to all cell and face shapes and is almost always used for prisms and pyramids Equiangular skew Another common measure of quality is based on equiangular skew. where:

is the largest angle in a face or cell, is the smallest angle in a face or cell, is the angle for equi-angular face or cell i.e. 60 for a triangle and 90 for a square.

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A skewness' of 0 is the best possible one and a skewness of one is almost never preferred. For Hex and quad cells, skewness should not exceed 0.85 to obtain a fairly accurate solution.

Figure: 4.10 Changes in terms of Angle Depicts the changes in aspect ratio For triangular cells, skewness should not exceed 0.85 and for quadrilateral cells, skewness should not exceed 0.9. Smoothness The change in size should also be smooth. There should not be sudden jumps in the size of the cell because this may cause erroneous results at nearby nodes. Aspect ratio It is the ratio of longest to the shortest side in a cell. Ideally it should be equal to 1 to ensure best results. For multidimensional flow, it should be near to one. Also, local variations in cell size should be minimal, i.e. adjacent cell sizes should not vary by more than 20%. Having a large aspect ratio can result in an interpolation error of unacceptable magnitude.

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4.8 Work Analysis: (drone) 4.8.1 Initial steps: here we are trying to create the mesh over a complete frame structure of a size 10mm for each element.

Figure: 4.11 10mm size of Meshing Element size = 10mm Type of meshing = mixed meshed (triangular, hexagonal) But results are not that much satisfactory to the meshing as it is not that much fine for more accurate result, so now we go for more fine meshing size that is less then 1mm.

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4.8.2 Final step: Here we have created a mesh of 0.8mm size for each element and it also provide us very accurate result as compared to our initial steps. Here the type of meshing is MIXED MESH.

Figure: 4.12 0.8mm size of Meshing

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Figure: 4.13 Different View of Meshing

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Chapter 5 Conclusion 5.1CONCLUSION: After studied all the desire property, we should conclude that “carbon fiber” will be the best light weight material for our drone manufacture, but it also have the very high cost factor , if it cross our budget and other factor then we may change the material to next best option i.e GLASS FIBER . After went through all the components very well, we found that RS2205 2300k BRUSHLESS DC MOTOR will be the best for our drone.

5.2FUTURE OF DRONE: Nowadays, drones are extremely popular and they have countless applications. However, in the future, they are going to be much better, so they will have even more applications. Even today, drones are used for transporting goods to remote locations, for surveillance and etc. In the future, we can expect to see drones that can do this much better. There are a lot of speculations on what drones will be capable for in the future. The most likely thing they will do is package transport. At this moment, Amazon is testing their Amazon Prime Air service. This means that when you order a package, it will be delivered to you in less than 30 minutes, instead of a few days. The materials, used in the manufacturing of drones are going to be changed as well. We can expect to see lighter materials that are stronger than materials used today. Paired with more efficient electric motors, future drones will fly longer and be able to reach higher speeds. Of course, we cannot ignore the military applications future drones will have. They will probably replace combat aircraft, therefore, reduce the number of lost lives! On the other side, some drones will be able to carry powerful weapons, so they will be used in conflicts. As you may believe, future drones will be used in surveillance, even more than today. Extremely small drones will be able to pass enemy lines and gain valuable information about the enemy army. Eventually, they will be able to collect all the data an army needs, so spies and spy satellites won’t be needed anymore.

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