uav vtol report
TRANSCRIPT
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Unmanned Aerial Vehicle Vertical Take-off and Landing
(UAV VTOL)
Final Report Session (2009-2013)
By
Waqas Bashir IS/92075/BSc/EE/A-09/M
Adeel Musa Kazim IS/92071/BSc/EE/A-09/M
Abdul Rehman Sohail IS/92082/BSc/EE/A-09/M
A Report submitted to the Department of Electrical Engineering
In partial fulfillment of the requirements for the degree of BACHELOR OF SCIENCE IN ELECTRICAL ENGINEERING
Federal Urdu University of Arts, Science, and Technology Islamabad, 44000, Pakistan
<July, 2013>
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Copyright 2011 by FUUAST All rights reserved. Reproduction in whole or in part in any form requires the prior written permission of Waqas Bashir, Adeel Musa Kazim, Abdul Rehman Sohail or designated representative.
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This research project is dedicated to our Teachers, Parents and to our beloved homeland PAKISTAN.
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CERTIFICATE OF APPROVAL
It is certified that the final year project’s work titled “UAV VTOL” is carried out by Waqas Bashir, Abdul Rehman Sohail, Adeel Musa Kazim, Reg. 92075, Reg. 92071, and Reg. 92082 under the supervision of Engr. Muhammad Saeed at Federal Urdu University of Arts Science and Technology, Islamabad. It is fully adequate, in scope and in quality, as a thesis for the degree of MS of Electronic Engineering.
Supervisor: ------------------------- Engr. Muhammad Saeed
Assistant Professor Department of Electrical Engineering
Federal Urdu University of Arts, Science and Technology, Islamabad
Internal Examiner: ----------------------------
Department of Electrical Engineering Federal Urdu University of Arts, Science and Technology, Islamabad
External Examiner: ----------------------------
Assistant Professor
Department of Electrical Engineering Federal Urdu University of Arts, Science and Technology, Islamabad
Chairman: ---------------------------- Dr. Zamin Ali Khan Assistant Professor
Department of Electrical Engineering Federal Urdu University of Arts, Science and Technology, Islamabad
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ACKNOWLEDGMENT
We thank to Allah Almighty who paved path for us, in achieving our desired goal. We express our profound sense of heartfelt gratitude and gratefully acknowledge the encouragement and guidance we received from our supervisor Asst. Professor Engr. Muhammad Saeed for readily agreeing to be our internal guide and also for his valuable guidance.
We are highly indebted to our co-supervisors Engr. Abrar Aziz and Engr. Faisal Baig of Electrical Engineering Department, Federal Urdu University of Arts, Science & Technology, Islamabad for their guidance and constant supervision as well as for providing necessary information regarding the project and also for their support in completing the project.
We have taken efforts in this project. However, it would not have been possible without the kind support and help of many individuals. We would like to extend our sincere thanks to all of them. We would like to express our gratitude towards our parents for their kind co-operation and encouragement which help us to work as our best for this project.
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DECLARATION
It is declared that the work entitled "UAV VTOL” presented in this report is an original piece of our own work, except where otherwise acknowledged in text and references. This work has not been submitted in any form for another degree or diploma at any University or other Institution for tertiary education and shall not be submitted by me in future for obtaining any degree from this or any other University or Institution.
Waqas Bashir
IS/92075/BSc./EE/A-09/M
Adeel Musa Kazim IS/92071/BSc./EE/A-09/M
Abdul Rehman Sohail IS/92082/BSc./EE/A-09/M
July 2013
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ABSTRACT
Now a day’s trend of small UAV’s has been increasing. With the availability of high power density batteries, power full micro controller, cheap air frames, long and short range radio devices and power full motors UAV’s are implemented in civilian works such that mapping, traffic control, search and rE.S.Cue operation. UAV VTOL’s are small in size and easy in operation. One or two people can operate this vehicle and easily carry in hand. No need of runway for this vehicle, this vehicle can easily take a lift. The UAV’s are designed to fly at low altitudes normally less than 1000 meters to give a close observation of the ground objects. The objective of this report is to provide practical and theoretical knowledge about UAV’s. The flight control is introduced first. The operating system and radio control is explained next in both hardware and software view points. In order to achieve our result and desired goal we worked on the sensors, micro controller and design an efficient body structure of balsa wood. First we design a prototype with foam; a lot of things are including in the body that includes Ailerons, Rudder, and Elevator etc. To make balanced structure we must care of the ailerons, rudder and wings dimensions, weight of the equipment, structure and thrust generated by the propeller to make a lift. To send or receive signals through microcontroller programming of controller has been done in Arduino software. As a result of completing the above procedure we learnt a lot of knowledge and new techniques in Engineering. Such that UAV body designing, Arduino programming, GPS works, sensors working and wireless data transmitting and receiving etc.
After doing work on this project we have learnt that more knowledge, study, skills and experience is required to work on UAV’s. But after doing work one can learn a lot of knowledge and experience and can design his/her own aerial vehicle.
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TABLE OF CONTENTS
Chapter 1
1 Introduction ...................................................................... 17
1.1 Over view .......................................................................................... 17
1.2 Working detail .................................................................................... 17
1.3 Initiating problem..................................................................................... 17
1.3.1 Project Goal .................................................................................... 18
1.3.1.1 Hardware Implementation .............................................................. 18
1.3.1.2 Position Detetminition .................................................................... 18
1.3.1.3 Tilt Measurement ............................................................................ 18
Chapter 2
Aerodynamics and construction of UAV Model .
2.1 Forces in Flight .................................................................................. 20
2.1.1 Thrust ................................................................................................. 20
2.1.2 Lift ………………………………………………………………..20
2.1.3 Drag ................................................................................................. 21
2.1.4 Gravity ............................................................................................... 23
2.2 Aerodynamics ................................................................................... 24
2.3 Wings Geometry definitions ............................................................. 25
2.3.1 Stability .............................................................................................. 25
Chapter 3
Methodologies and Implementation…………. ................................. 30
3.1 Design of Investigation ................................................... 30
3.2 UAV Model Analysis and Procedure ............................................... 30
3.2.1 Part DE.S.Cription of UAV Model ................................................... 31
3.2.2 Propeller ............................................................................................ 31
3.2.3 Spinner .............................................................................................. 31
3.2.4 Rudder ............................................................................................... 31
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3.2.5 Fuselage ............................................................................................ 31
3.2.6 Ailerons ............................................................................................. 31
3.2.7 Wings ................................................................................................ 31
3.2.8 Stabilizer ........................................................................................... 31
3.3 Implementation Procedure ................................................................ 32
3.3.1 Body Size and dimensions ................................................................ 32
3.3.2 UAV model Construction ................................................................. 34
3.3.3 Wings ................................................................................................ 35
3.3.4 Propeller ............................................................................................ 36
3.3.5 Stabilizer ........................................................................................... 37
3.3.6 Body Dimensions .............................................................................. 37
3.3.7 Weight Calculation ........................................................................... 38
Chapter 4
4 Sensor list …………………………………………………………………………………….. 40
4.1 GPS………………………………………………………………. 40
4.1.1 Latitude…………………………………………………………… 40
4.1.2 Longitude …………………………………………………………. 40
4.1.3 Time……………………………………………………………… 41
4.2 Data Pattern………………………………………………………. 41
4.3 Pictorial View and Pin Configuration 42
4.4 Accelerometer 42 4.4.1 Accelerometer used in our project ……………………………….. 42
4.4.2 Features…………………………………………………………… 43
4.4.3 Applications……………………………………………………… 43
4.4.4 Pin Configuration………………………………………………… 44
4.5 Gyro Sensor………………………………………………………. 44
4.5.1 Gyro Used in Our Project………………………………………… 45
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4.5.2 Features………………………………………………………… 45
4.5.3 Applications……………………………………………………. 45
4.6 Barometric Pressure Sensor……………………………………. 45
4.6.1 Barometric Pressure Sensor in Our Project……………………. 46
4.6.2 Features………………………………………………………… 46
4.6.3 Applications……………………………………………………. 46
4.6.4 Measurement of Pressure and temperature…………………….. 46
Chapter 5
5 Ground Station…………………………………………………. 48
5.1 Base Station Main Processing Board………………………….. 48
5.1.1 Xbee Module…………………………………………………… 48
5.1.2 Level Converter………………………………………………… 48
5.2 Graphical User Interface………………………………………. 49
5.2.1 Data Flow Programming……………………………………….. 49
5.2.2 Graphical Programming……………………………………….. 49
5.3 Our GUI………………………………………………………… 50
5.3.1 Visa Resource Name…………………………………………… 50
5.3.2 Headers…………………………………………………………. 52
5.3.3 Visa Read Palette………………………………………………. 54
5.3.4 3D Curve Graph………………………………………………… 54
5.3.5 Execution Control………………………………………………. 55
5.4 Data Conversion………………………………………………… 56
5.5 Possible Errors…………………………………………………. 58
5.6 Xbee Module…………………………………………………… 58
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5.6.1 Specifications………………………………………………….. 59
5.6.2 Pin Configuration………………………………………………. 59
5.6.3 Transmitter Xbee………………………………………………. 59
5.6.4 Receiver Xbee…………………………………………………. 59
5.7 Encryption …………………………………………………….. 60
Chapter 6
6 Block Diagram of Project………………………………………. 62
6.1 Base Station…………………………………………………….. 62
6.2 VTOL vehicle………………………………………………….. 63
6.3 Hardware Used with Technical Specifications…………………. 64
6.3.1 DC Brushless Motor……………………………………………. 64
6.3.2 Propeller………………………………………………………… 65
6.3.3 Radio Transmitter/Receiver……………………………………... 65
6.3.4 E.S.C…………………………………………………………….. 66
6.3.5 Servo Motor …………………………………………………. 66
6.3.6 Push Rod………………………………………………………. 66
6.3.7 Controller………………………………………………………. 67
6.4 Software Used…………………………………………………. 68
6.4.1 Arduino…………………………………………………………. 68
6.4.2 Lab view……………………………………………………….. 69
6.4.3 Hyper Terminal……………………………………………….. 69
6.4.4 X-CTU…………………………………………………………. 69
6.4.4.1 AT Command Mode6…………………………………………. 69
6.4.4.2 API Command Mode…………………………………………. 69
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Chapter 7
7 Hardware/Software Results…………………………………… 71
7.1 Comparison with Initial Goal…………………………………. 72
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LIST OF FIGURES
Chapter 2
Figure 2.1………………………………………………………………………. 20
Figure 2.2………………………………………………………………….......... 21
Figure 2.3………………………………………………………………………. 22
Figure 2.4……………………………………………………………………….. 22
Figure 2.5………………………………………………………………………. 23
Figure 2.6………………………………………………………………………. 23
Figure 2.7………………………………………………………………………. 24
Figure 2.8………………………………………………………………………. 25
Figure 2.9………………………………………………………………………. 26
Figure 2.10…………………………………………………………………….. 27
Chapter 3
Figure 3.1……………………………………………………………………… 30
Figure 3.2………………………………………………………………………. 32
Figure 3.3…………………………………………………………………….. 33
Figure 3.4……………………………………………………………………… 34
Figure 3.5………………………………………………………………………. 35
Figure 3.6………………………………………………………………………. 36
Figure 3.7………………………………………………………………………. 37
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Chapter 4
Figure 4.2………………………………………………………………………. 41
Figure 4.3……………………………………………………………………….. 42
Figure 4.4………………………………………………………………………. 43
Figure 4.5……………………………………………………………………… 44
Figure 4.6……………………………………………………………………….. 44
Chapter 5
Figure 5.1………………………………………………………………………. 48
Figure 5.2………………………………………………………………………. 50
Figure 5.3………………………………………………………………………. 51
Figure 5.4………………………………………………………………………. 51
Figure 5.5………………………………………………………………………. 52
Figure 5.6………………………………………………………………………. 52
Figure 5.7………………………………………………………………………. 54
Figure 5.8………………………………………………………………………. 54
Figure 5.9……………………………………………………………………… 55
Figure 5.10………………………………………………………………………. 56
Figure 5.11…………………………………………………………………….. 57
Figure 5.12……………………………………………………………………… 57
Figure 5.13……………………………………………………………………… 58
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Chapter 6
Figure 6.1………………………………………………………………………… 62
Figure 6.2………………………………………………………………………… 64
Figure 6.3………………………………………………………………………… 65
Figure 6.4………………………………………………………………………… 65
Figure 6.5………………………………………………………………………… 66
Figure 6.6………………………………………………………………………… 66
Figure 6.7………………………………………………………………………… 67
Figure 6.8……………………………………………………………………….. 67
Figure 6.9………………………………………………………………………… 68
Chapter 7
Figure 7.1……………………………………………………………………….. 71
Figure 7.2……………………………………………………………………….. 72
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CHAPTER 1
INTRODUCTION
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1 Introduction to UAV 1.1 Overview:
Vertical takeoff landing (VTOL) Unmanned Aerial Vehicle (UAV) is an aircraft that can take off in a vertical mode and also land in a vertical mode. This aircraft is ideal for operating in areas where runways are not accessible. There are vast applications of such aircraft. The applications of such an aircraft are ranging from civilian transport to aero medical evacuation. Now such aircrafts have been limited to military and research applications. UAV VTOL’s are small in size and easy in operation. One or two people can operate this vehicle and easily carry in hand. No need of runway for this vehicle, this vehicle can easily take a lift. The UAV’s are designed to fly at low altitudes normally less than 1000 meters to give a close observation of the ground objects. Similar benefits exist for scaled model Remote Controlled (RC) VTOL vehicles. These needs and potential applications provide the motivation for this design project, in the anticipation of designing and building a model VTOL aircraft that is able to be controlled remotely and affordable.
1.2 Working detail:
VTOL means vertical takeoff and landing. This plane will not run on any run way it will start its take off from any congested place and will land down as well. Whole the flight will be fully controlled by sensors like gyro for angular motion and acceleration and accelerometer for linear acceleration. GPS used for position determination of the plane.
Arduino 2560 microcontroller is being used. This controller receives data from all sensors and sends them instructions according to the situation.
The body of the plane contains propeller on top and sensors inside the body. Under the propeller there will be two sets of blades. These blades are used for the left right and forward backward motion control.
At one time one set will be moving while the other will be constant and vertical position. This makes the maximum air to fall on a specific direction for the maximum thrust to be generated.
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1.3 Initiating Problem:
The idea of this project is to use a small model of UAV VTOL. This UAV must be able to carry out the whole operation from take-off to landing without human interaction. A ground station connected to the UAV by a wireless link. This means that the procedure for an operation can look like this.
• Constructing a simple VTOL and introducing UAV Aerodynamics and Avionics.
• The ground station connects to the UAV and the spatial information is uploaded in Graphic User Interface via wireless link.
• The UAV takes off and start communication with the base station.
1.3.1 Project Goal: The goal of the project is to vertically take off and land the UAV. The project is
divided into different steps as follows.
1.3.1.1 Hardware Implementation: The UAV model is made up of Thermo poll, propeller is in center and carries an on-board system unit that contains different types of sensors e.g. Accelerometer, Gyros, Barometric pressure sensor, GPS, Controller, Battery for stable power supply and a transmission unit for wireless link.
1.3.1.2 Position determination: It is necessary to determine the position of UAV. A GPS (SKM 53) is
used for this purpose.
1.3.1.3 Tilt measurement: A gyro sensor is used for tilt (Roll, Pitch, and Yaw) measurement of
UAV. For this purpose we used 10DOF sensor which consists of • 3 axis Accelerometer • 3 axis Gyro
• 3 axis Magnetometer and • A barometric pressure sensor.
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CHAPTER 2
BASIC AERODYNAMICS
And UAV ELECTRONICS
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BASIC AERODYNAMICS
2 Aerodynamics:
2.1 Forces in Flight: • Thrust
• Lift • Drag
• Gravity
Fig. 2.1
2.1.1 Thrust: The mechanical force generated by some kind of propulsion system to
move the aerial vehicle through the air. Thrust is always used to overcome the drag force and thrust should always be greater than the weight of the aircraft otherwise the aircraft will not move to the air. Thrust is a vector quantity as it has magnitude and some direction. The direction of the thrust depends how the engine attached to the aircraft. The magnitude of the thrust depends upon the following factors
• Type of Engines
• Number of Engines • Throttle setting speed
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Fig. 2.2
Thrust generated by Propeller
2.1.2 Lift: Lift is the force that directly overcomes the weight of the aircraft. Lift is
obtained by the thrust generated by the propeller. Lift is generated by every part of the aircraft but mostly lift is generated by wings. Lift is generated by the difference of velocity. There must be a difference of velocity between solid object and the fluid. There must be a motion between the object and the fluid. No motion, no lift. Lift force = 0.5 x r x V2 x wings lift coefficient x wing area Where Lift force is in Newton Wing Area in meter square Air speed in m/s Wings lift coefficient depends on the air foil type
2.1.3 Drag: Drag is the aerodynamic force that opposes the aircraft motion through the air. Drag is generated by every part of the aircraft (even the engines). It is an aerodynamic resistance to the motion of the object through the air. Drag force opposes the thrust force. Drag force is generated through the interaction and contact of a solid body with fluid. It is generated by almost all parts of the aircraft.
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Fig. 2.3
For drag to be generated, the solid body must be in contact with the fluid. If there is no fluid or no contact between the fluid and the solid body no drag will be generated. There are many sources of drag Skin Friction: One of them is skin friction between the molecules of air and the body of the aircraft. Skin friction causes the air near the wing to slow down. This slows down of the air is called boundary layer. The boundary layer becomes thicker when moving from the front of the airfoil to the trailing edge. Reynolds effect: Slower we fly the thicker boundary layer become. Form Drag: It is another source of drag. It depends on the shape of the aircraft. As long as the air flow through the surface of the aircraft the local velocity and the pressure changes. The component of the aerodynamic force present on the wing that oppose the motion is the wing`s drag while component on the perpendicular side is the wings lift.
Fig. 2.4
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Induced Drag: Induced drag is a sort of drag caused by the wings generation of lift. This drag is induced due to the pressure difference between the top and the bottom of the wing.
Fig. 2.5 Parasitic Drag: All the drag which is not associated with the lift called parasitic drag. Total drag is equal to Induced drag plus parasitic drag.
Fig. 2.6
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2.14 Gravity: Gravity is always directed towards the center of the earth. The magnitude of the force depends upon the mass of all the aircrafts parts. The gravity is also called weight and is distributed throughout the body of UAV. During flight UAV rotates about its center of gravity, but the direction of weight is always remains towards the center of the earth.
2.15 Aerodynamics:
• Roll
• Pitch
• Yaw
Roll:
Movement of UAV along its own axis called Rolling.
Pitch:
Movement of UAV in upward and downward direction i.e. take-off and landing.
Pitch is along x-axis.
Yaw:
Movement of UAV in Right and Left direction called yawing.
Fig. 2.7
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2.16 Wing Geometry Definitions: The cross section of the wing has some geometry definitions as shown in the figure below.
Fig. 2.8
• Chord Line: Chord line is the line that cuts the air foil from the leading edge and the trailing edge.
• Mean camber line is the line that lies between the upper and the lower surfaces.
• Camber is the distance between the mean chamber line and the chord line.
• Aspect Ratio:
Span divided by the wing area is called the aspect ratio.
2.16.1 Stability Concepts: The momentary disturbance of the aircraft in each of three axis is associated with the
intrinsic level of stability occurring without any interruption of pilot.
In case of UAV’s some trim devices has been used which are adjustable during flight? Too much control of the aircraft may cause dynamic instability. An entirely steady aircraft may come back to its stable state without the interruption of pilot. But such aircrafts are rare. We usually required aircrafts which are stable and are easy to fly. Too much instability is also an undesirable characteristic. In supersonic aircrafts instability can be continually corrected by on board computers rather than pilot.
Aircrafts stability is expressed according to each axis:
• Lateral stability (Stability in roll ) • Directional stability (Stability in Yaw) • Longitudinal stability (stability in pitch)
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Positive Stability:
In positive stability aircraft tends to return its original state after disturbance.
Negative Stability:
In negative stability aircraft tends to increase the disturbance.
Neutral Stability:
In neutral stability aircraft remains at the new condition.
Static Stability:
In static stability aircrafts refers its initial response to a disturbance.
Dynamic Stability:
In dynamic stability aircraft refers the response over time to disturbance.
• A static stable aircraft may be dynamically unstable. • Dynamic instability may be achieved by the distribution of weight inside the
fuselage. • Lateral stability can be achieved by sweep back, keel effect and the proper
distribution of weight.
Fig. 2.9
If one wing drops due to disturbance, the lower wing will receive more lift and the aircraft will roll back into horizontal state. When an aircraft with sweep back to slip or drop a wing due to disturbance the low wing presents its leading edge to relative air flow. As a result low wing acquires lift restoring the aircraft to its original state.
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Keel effect occurs with the high wing aircraft. These are literally stable because wings are attached in a high position on fuselage. The fuselage behaves like a keel. When one wing dips and the aircraft disturbed, than the fuselage behaves like a pendulum returning the aircraft to the horizontal level.
Longitudinal stability depends on the location of the center of gravity that how far the stabilizer placed from the main wing.
Symmetrical airfoils have a pitching moment zero, resulting in neutral stability. Means the aircraft goes where you point it.
Refluxed airfoils have a positive pitching moment, makes aircraft naturally stable, often used with flying wings.
In order to achieve a stable flight the center of gravity must be at the right point. In order to get a longitudinal stability center of gravity must be ahead of neutral point, which is called the aerodynamic center.
The angle of fuselage to the direction of flight affects its drag. A tail heavy aircraft will be unstable during landing approach to ground and a nose heavy aircraft will be unstable during taking lift from ground. It requires a high speed to take a lift.
The angle of flying surface related to common reference line is called Angle of incidence. The reference line must be at level position during stable flight or when the fuselage in its low drags position.
When aerodynamic force is applied at a point ¼ from leading edge of the rectangular wing than the magnitude of aerodynamic remains constant even when angle of attack changes. This point is called wings aero dynamic center.
Fig. 2.10
To get a good longitudinal stability center of gravity must be close to aerodynamic center. For the wings which are not rectangular we have to measure
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the Mean Aerodynamic Chord (MAC). MAC is the average of the whole wing.
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CHAPTER 3
METHODOLOGIES AND
IMPLEMENTATION
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3 Methodologies and Implementation 3.1 Design of the Investigation
The design of the UAV is investigated from various sources and research. After studying various related articles the final hardware is finalized. Some of the related techniques for body designing are as follows.
3.2 UAV Model Analysis and Procedure:
UAV model with parts is shown in figure below.
Fig. 3.1
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3.2.1 Part DE.S.Cription of UAV Model 3.2.1.1 Propeller:
The propeller converts rotational motion into thrust and speed depends upon the diameter, pitch and engines power.
3.2.1.2 Spinner: It is the streamlined part of the propeller that covers the end of the propeller`s shaft.
3.2.1.3 Rudder: Moveable part fitted to servo`s shaft used to change the direction of the aircraft.
3.2.1.4 Fuselage: The body of the UAV is called the Fuselage.
3.2.1.5 Ailerons: A pair of the moveable blades attached to the servo`s shaft called ailerons. Ailerons are the moveable parts connected on both sides of the wings. They are used to make aircraft Roll. When one part of the ailerons moves up the other moves down.
3.2.1.6 Wings: Wings provide the aircraft main lifting force.
3.2.1.7 Stabilizer: Stabilizers are used to attain longitudinal stability. They are also called horizontal stabilizer.
3.2.1.8 Fin: Fin is also called the vertical stabilizer. Rudder is connected to fin which helps in yaw.
3.2.1.9 Cowl The front molded body at front is called the cowl. It helps the air flow to go smoothly and provide a proper path for air.
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3.3 Implementation Procedure:
By reducing the dimensions of large aircraft, a scale model has been formed. However it is easy to fly. The main aerodynamic difference among a large aircraft and this modeled aircraft is originated from boundary layer.
3.3.1 Body size and dimensions: Fig. 3.2
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Fig. 3.3
The main features about the designing of the aircraft are shown in the above figures. The control surface design of the UAV depends on the thrust generated by the engine.
Similarly the size and weight of the body also matters on the thrust generated by the propeller.
During take off a nose heavy aircraft will be unstable. A tail heavy aircraft will be unstable
during landing approach.
In the table below size of wings recommended with respect to engine size.
Engine Size with respect to wings area
C.C C. In. Area sq. dm Area sq. in
0.8 0.049 12-16 200-250
1.6 0.10 15-22 250-350
2.5 0.15 20-30 300-450
4.0 0.25 26-32 400-500
6.7 0.40 32-45 500-700
10 0.60 38-55 600-850
Table 3.1
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3.3.2 UAV model Construction: After working on the techniques and procedure above, final UAV model is as under. Body is made up of Thermo poll.
Fig. 3.4
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3.3.3 Wings:
Fig. 3.5
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3.3.4 Propeller:
Fig. 3.6
3.3.5 Stabilizer:
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Fig. 3.7 3.3.6 Body Dimensions:
Length of the UAV 42 inches
Thickness of Body 24 inches (2 feet)
Stabilizer 8 inch
Push Rod 12 inch
Aileron 6 inch
Area of Propeller 8 inch
Diameter of Propeller 6 inch
3.3.7 Body Load Calculation:
Propeller can generate a thrust of 1 kg, so total weight of the body should be equal to or less than 1 kg. weights of the equipments are given below
E.S.C = 39 g Brushless moto = 50 g Servos = 22 g (11 gram each) Weight of Circuitry= 170 g Weight of Body = 190 LiPo. Battery = 129 gram Total Weight on Body = 600 g
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CHAPTER 4
SENSORS
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4 Sensors List:
We have used following sensors in our project.
• GPS
• Accelerometer • Gyro • Barometric Pressure sensor
4.1 GPS:
GPS stands for global positioning system. It gives position of any vehicle. GPS is used in many devices. Now days it is also available in mobile phones. It gives data of longitude, latitude, date, time and speed. It depends on the programmer that what kind of data he wants from the GPS. Almost every GPS uses 4 satellites for acquiring data.
In our project we have used skm53 GPS. It is very efficient and small size GPS. It has a path antenna. Skm53 is easy to mount on Arduino controller as it needs only four pins to attach.
• Tx with Tx of controller
• Rx with Rx of controller • One pin for Vcc(5v)
• One pin for Gnd
There is available a library for this GPS called TINY GPS. It automatically calls functions of GPS.
4.1.1 Latitude:
Latitude is used to express that how far the vehicle is form north of south, relative to the equator. If the vehicle is on the equator its latitude will be zero. If the vehicle is near north poles the latitude is nearly 90 degree north and vice versa. Geo stationary satellites are not visible in small regions near north and south poles. Because satellites are below horizon and above the equator.
4.1.2 Longitude:
Longitude shows the direction of vehicle in east west direction according Greenwich Meridian. Those countries which are on the left side of the Greenwich have longitudinal angle up to 180 degree east. And those
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countries which are on the right side of the Greenwich meridian have angle up to 180 degree west.
4.1.3 Time:
GPS also gives the time during flight. This time is according to Greenwich Meridian time. Pakistan is in zone GMT+5. So according to readings of GPS we added 5 hours to that time and it was exactly showing Pakistan’s standard time.
4.1.4 Data Pattern:
Our GPS was giving data in the following pattern.
Figure 4.2 GPS Data Pattern
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Figure 4.3 GPS
4.2 Accelerometer:
It consist a moveable mass that slides along the sensitive axis in any case. Springs are used to fix the movement of the mass. When case is accelerated the mass due to inertia remain stationary.
Acceleration is gravity sensitive when its sensing axis is positioned gravity moved the mass. By this way we use gravity for testing purpose but there is a problem in measuring acceleration. It gives the maximum value when the unit is vertical with the sensing element and zero when unit is horizontal with the sensing axis.
4.2.1 Accelerometer used on our project:
Accelerometer ADXL345 is used in our project it is a small thin low power and 3 axis accelerometer.
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Figure 4.4 Accelerometer functional block diagram
4.2.2 Features: • Ultralow power: 40uA in measuring mode and 0.1uA in standby mode
• Usage of power is automatically scales with bandwidth • Resolution: fixed 10bit resolution • Embedded patent pending FIFO technology minimizes host processor load • Tap/double tap detection • Activity/inactivity monitoring • Free-fall detection • Supply voltage range: 2.0 V to 3.6V Wide temperature range (−40°C to +85°C)
10,000 g shock survival • Small and thin: 3 mm × 5 mm × 1 mm LGA package.
4.2.3 Applications: • Medical instruments
• Industrial instruments • Navigation devices • Hard disk derive
• Fitness equipment’s
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4.2.4 Pin Configuration:
Figure 4.5 Pin Configuration
4.3 Gyro Sensor:
A gyroscope is a device used to measuring or maintaining orientation that is based on the principles of angular momentum. This device is like a wheel or disk whose rotor orientate freely. This change in orientation gives to less torque that to its rate of spin. Since external torque is minimized by mounting the device in gimbals, its orientation remains nearly fixed, regardless of any motion of the platform on which it is mounted.
Figure 4.6 Basic Gyroscope
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4.3.1 Gyro Used In Our Project:
Gyro used in our project is L3G4200D. it is a digital gyro sensor. It gives the roll, pitch and yaw of the plane.
4.3.2 Features: • Three selectable full scales • I2C/SPI digital output interface
• 16 bit rate value data output • Two digital output lines • Integrated low and high pass filters with user selectable bandwidth
• Embedded self-test • Wide supply voltage, 2.4 V to 3.6 V
• Low voltage compatible IOs, 1.8 V • Embedded power-down and sleep mode • High shock survivability
• Extended operating temperature range (-40 °C to +85 °C)
4.3.3 Application: • Motion control with man machine interface • GPS navigation system
• Application and robotics • Gaming and virtual reality input devices
4.4 Barometric Pressure Sensor:
Barometric pressure sensor is used to calculate pressure of air vehicle with respect to see level. It also used to measure temperature and altitude of the body with respect to see level. See level is a standard of measuring altitudes of any body. It is a surface mount devoice and these devoices damaged so early.
It is a digital device gets digital data with serial port from the controller. It gives a serial output with a device have analogue data.
Barometric air pressure sensors are used to measure the pressure in air of air vehicles. It widely used to measure fuel ratio that gives the engine continuity for running. It also control the spark for made the engine more efficient. It is fully integrated so it is widely used in automobiles.
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4.4.1 Barometric Pressure Sensor Used in Our Project: We used BMP085 in our project. It is digital pressure sensor. It operates a
very low voltage of 3.6 volts
4.4.2 Features: • Pressure ranges from 300 to 1100hpa +9000m to -300m • Supply voltage 1.2 to 3.6V.
• Low power 1 cycle / sec • Low noise o.o6hpa at ultra-low power
• Temperature measurement • I2C interface
• Fully calibrated
4.4.3 Applications: • Used in GPS navigation system
• Indoor and outdoor navigation • Leaser and sports • Weather forecast system
• To show vertical velocity of bodes
4.4.4 Measurement of Pressure and Temperature:
Microcontroller sends a signal that is a start signal to BMP for the calculation of pressure and temperature. It calculates pressure in HPA and temperature in degree centigrade. The sampling rate can be increased to 128 per see. For serial communication i2c interface is used.
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CHAPTER 5
GROUND STATION
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5 Ground station: Ground station consists of three main parts listed below.
• Base station main processing board • Graphical user interface • Radio control system
5.1 Base station main processing board:
Figure 5.1 Main Processing Board Flow Diagram
5.1.1 Xbee Module:
Xbee module is a pair of wireless transmitter and receiver. Transmitter sends data from VTOL vehicle and it is being received on ground station with Xbee receiver. The data is then converted to CMOS logic level to be read by computer. Xbee used here is 1mW Series 1 xbee module.
5.1.2 Level Converter:
Level converter is used to convert the TTL logic level to CMOS level. MAX232 circuit is used for this conversion. This converter passes data to computer via serial port interface.
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5.2 Graphical User Interface (GUI):
Graphical user interface means the representation of real world data in graphical form. We have used lab view for this purpose. Lab view receives data from serial port. The data is in the form of string. Firstly it is converted into decimal and then separated and extracted specific data ranging in specific bits and represented in allocated space.
GUI consists of two main parts. One is called front panel and the other is called block diagram panel.
Front panel consists of output graphs and indicators and block diagram panel consists of functional components. These components are joined with each other and data is fed from one block to other and so on.
5.2.1 Data Flow Programming:
The programming used in lab view is called data flow programming. On block diagram panel different functional nodes are connected by drawing wires. These wires send data from one to other node. Programming language is capable of parallel execution.
5.2.2 Graphical Programming:
Lab view programs are called Virtual Instruments (VIs). Each VI is being divided in three parts.
• diagram
• Front panel • Connector panel
Connector panel is used to call a VI in another VI. The controls and indicators on front panel are used to input data into or to extract data from a running VI. The graphical programming facilitates a non-programmer to just drag and drop virtual instruments with which they are familiar.
The Lab view programming environment with built in examples and available documentation makes it simple and easier to develop small applications. This is its benefit on one side, but on the other end there is great danger of neglecting the expertise needed for good quality graphical programming. Because for complex algorithm and large scale code, it is essential for the programmer to have full and advance knowledge of all functions and features of Lab view.
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5.2.3 Our GUI:
We have made a GUI on ground station, receiving data form serial port.
It gives a graphical representation of plane orientation, position, atmospheric pressure and temperature. It also shows the height of VTOL vehicle form sea level.
Data is read in the form of bytes and the output is in the form of strings. Some graphs do not support the string data so data conversion was done before plotting the graphs.
Figure 5.2 GUI Front Panel
5.2.4 VISA Resource Name:
There is a text box named Visa Resource name. Visa is because of Visa palette. Visa palettes are used for serially data transmission and receiving in lab view. Visa resource is used for the detection of serial port through which serial transmission is to be done. It is done through Visa Configure palette.
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Visa palettes are shown in following diagram.
Figure 5.3 Visa Palettes
Figure 5.4 Visa Configure
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Com port means communication port. Communications port is available at program at a time. That means one can’t use serial communication on two programs like in hyper terminal and Lab view.
In Figure 5.4 baud rate box is the constant which is defines for serial communication. Baud rate is the bits per second transmission of data however it can be changed. But the change must be in the program written for the data for synchronization.
5.2.5 Headers:
Arduino microcontroller sends data continuously on serial port, so there is a lot of chance of data to get mixed. And it is very difficult to differentiate it and feed it to respective graphs and boxes. For that purpose headers are included in the program.
Headers are basically those alphabets which are transmitted from Lab view to controller. By doing this controller does not send signal all time, but it sends data from the sensors when it is asked to. Each of the headers sent is for the specific data. For example in our code ‘t’ is sent to tell the controller to send data of temperature sensors and similarly ‘p’, ‘h’, ‘x’, ‘y’, ‘z’ are the headers sent for pressure, height, gravitational acceleration along x, y and z direction similarly.
In lab view simple Visa write palettes are used for this purpose.
Figure 5.5 Visa Write
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In our project following Visa write headers are used.
Figure 5.6 Headers for project
• Accelerometer headers:
For X-axis =x
For Y-axis =y
For Z-axis =z
• Gyro Headers:
For X-axis =q
For Y-axis =w
For Z-axis =e
• Barometric Pressure Sensor headers:
For Pressure =p
For temperature =t
For Height =h
• GPS Headers:
For Date =d
For Time =t
For Latitude =m
For Longitude =n
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These headers can also be defined as passwords for sensor data used in any industry.
The data will not be transmitted until exact alphabets (headers) are transmitted from base station.
5.2.6 Visa Read Palette:
Visa read palettes are used for reading data from serial port. For multiple data reading and writing multiple palettes are connected in series. Each palette reads the data in a sequence and byte by byte. Byte size is defined before the reading of the data. If defined byte size does not equals the byte size of the data being received at the serial port the data will not be picked and processed by the lab view.
Figure 5.7 Visa Read Palette
5.2.7 3D Curve Graph:
The graphical representation of data acquired from gyro and accelerometer involves 3D graphs. Because the data is in 3 dimensions and it needs proper waveforms. We have used 3D curve graphs. It takes input of array, so the data received from Visa Read palette is converted into decimal first and then into array form.
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Figure 5.8 Front Panel and Block Diagram View of 3D curve
Figure 5.8 explains 3D curve graph in a meaningful way. On the right side there are three inputs shown as x-vector, y-vector, z-vector. These are converted output readings of Visa read palettes. Data acquired is continuously updated in read buffers and graphs exhibits readings after specified time delay.
5.2.8 Execution control:
Serial palettes work in a sequence, when multiple palettes are joined in series they are separated by flat sequence. So each palette executes on by one. All these palettes are placed in a while loop for the sake of continuous operation. For loop can also be used instead of while.
Flat sequence terminates after each block if further not connected with the next palette. If any of palettes is not connected Lab view will not start operation.
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Figure 5.9 Execution Control
Figure 5.10 Flat Sequence and While Loop
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5.3 Data Conversion:
Data transmitted from the serial port is in the form of strings. This format is not acceptable to graphs in Lab view. So conversion is done with the data received.
For simple 1-D graphs data is converted from string to decimal form.
For this purpose string to decimal converter is used.
Figure 5.11 String conversion palettes
In figure 5.11 different palettes of string to other conversion are shown.
Figure 5.12 String to number converter
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In figure 5.12 string to number converter is shown. It takes a input of string data and converts it to number form. If input data is ‘0.41’ the output may be shown as ‘0’.
Figure 5.13 Strings to Array
In figure 5.13 strings is converted in the form of array. This conversion is done because 3-D graphs don’t support string or decimal data. For that purpose an array is build.
5.4 Possible Errors:
During acquiring data following errors occurred in our GUI.
• Time out error: Time out error appears when lab view fails to get the data in defined time.
Possible solution for this error is increasing time from Visa Configure palette.
• Non availability of serial port: This error occurs generally when serial port is being used in any other program and meanwhile you start accessing it from lab view.
• Components no attached: When any single of components is not attached Lab view does not start
processing.
• Baud rate: Baud rate must be selected properly. It should match the baud rate which is selected in coding.
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5.5 Xbee Module:
Xbee module is used for wireless data transmission from plane to base station. An xbee transmitter in on VTOL vehicle and the xbee receiver is connected on base station. On the receiving end level conversion is done for changing parallel data to serial data for making it compatible for serial port transmission.
5.5.1 Specifications:
Model
Xbee series 1
Operating frequency 2.4 GHz Indoor range 30 m Outdoor range 9o m Power 1mw Voltage required 3.3 Tx peak current 45 mA @3.3V Rx peak current 50 mA @3.3V Table 5.1 Specifications
For data transmission AT command mode for API mode is used in programming.
5.5.2 Pin Configuration:
Both of the xbee’s can be used alternatively. Both have same pin configuration. But it is necessary to initialize them as transmitter or receiver.
Pin1 Vcc Pin 2 Transmitter Pin 3 Receiver Pin 10 Ground Table 5.2 Pin configuration
We are using only four pins for data transfer. Same configuration is one the receiver end.
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5.5.3 Transmitter Xbee:
Transmitter xbee is connected with the Arduino microcontroller. It sends the data of sensors to xbee module. Xbee is attached on the communication pins (1, 0) of the transmitter. Transmitter of xbee is connected with the receiver of controller and receiver is connected with the transmitter pin of the controller.
5.5.4 Receiver Xbee:
Receiver xbee is connected with xbee base. Xbee base is used for interfacing of xbee with RS-232. Xbee is mounted over the base and it is connected with the power supplies. RS-232 is level converter. It converts TTL logic level to CMOS level and vice versa. Computer does not respond to TTL logic level because TTL means 5V operations bute computer analyze a signal of 12 V.
Moreover it converts parallel to serial data. Xbee sends the data in the form of packets.
Each packet made of 4 bytes. This data is converted in the serial form and transmitted to serial port.
5.6 Encryption:
Xbee has also a feature of encryption of data. Data is encrypted so that only the receiver pair of our xbee will receive it and others will not be able to read your data.
And the other way of sending the data is by sending it openly. All the xbee’s in the range of that data will receive it.
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CHAPTER 6
TOOLS AND TECHNIQUES
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6 Block Diagram of Project:
Block diagram gives the complete overview of project. It tells fundamental working phenomenon.
Fig. 6.1.
There are two parts of our block diagram. One is base station and the other one is VTOL vehicle.
6.1 Base Station:
One the base station side we have basically three main components. First one is radio transmitter. Using radio transmitter control signal is transmitted to VTOL plane. This transmitter has 6 channels and we are using only three of them. One channel is used for propeller and dc brushless motor controlling. And other two are used for controlling the movement of ailerons. However we third could also have been used for rudders. But we have fixed rudders. These fixed rudders are called stabilizers.
This is Futaba company transmitter having range of 600 meter. And its operating frequency is 2.4 GHz. Battery timing of this transmitter is approximately 39 minutes of flight.
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Second part on the base station is Xbee receiver. Its operating frequency is also 2.4 GHz. It receives signal of sensors transmitted by Xbee transmitter form VTOL body. Received signal is further transmitted to GUI after level conversion.
Then the third step is GUI of the project. Our GUI gives the complete graphical representation of all data received from the sensors connected to body.
6.2 VTOL Vehicle:
Second part of block diagram focus on the VTOL body. Components placed on the body are shown in two parts.
First part starts with radio receiver. This receiver gets radio signal from the transmitter of base station. This signal is received by the antenna of the receiver and it converts this radio signal into tiny current. This current is passed to receiver circuit. Receiver then demodulates the signal and extracts useful information from it. This information is then used to control servos and propeller speed accordingly data received.
An E.S.C is attached with the receiver. E.S.C means electronic speed controller. It limits the current supplied to the dc brushless motor by doing fast switching of FET transistor. By fast switching of transistor voltage and current is varied and speed of brushless motor. E.S.C can also be used to change the direction of motor and can be used as dynamic breaker. Some of new E.S.C’s have battery eliminating circuits (BEC) built in them. BEC is used for eliminating the need of battery supply for receiver circuit.
DC brushless motor is attached with the E.S.C and this is how its speed is being controlled. Brushless motors are preferred over motors having carbon brushes due to following reasons. Brushless motors have very high speed rotation. Our motor model is D2826 and it has rpm of 2200/volt. Voltage supply is 11 volt. So, total rpm of motor becomes 24200.
This figure shows how fast motor rotates. It also reduces the effect of friction and wearing out of brushes.
A propeller with dimension 6*4 mounted over the motor. It has length of 6” and pitch of 4”. This propeller generates a thrust of approximately 1kg. And the weight of our body is approximately 600g. That means we can attach a weight of 400g. Pitch of propeller defines the distance covered by in one complete rotation.
Two servo motors are attached with the receiver. These servos are used to control the ailerons and stabilizers. Servo motors get the update of control signal after every 20ms. If the duration of next signal received is less then 10ms that means servo is to rotate at angle of 90.
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Similarly in the second part of VTOL vehicle diagram there is a controller in the center. This controller sends and receives information from the sensors attached with it. This data is transmitted to controller using inter integrated circuit and other communication ports. Controller executes all the commands in a sequence. When data is received from sensors then it is transmitted to base station using Xbee transmitter. It works on the baud rate of 19200. Data is sent in parallel mode.
6.3 Hardware Used With Technical Specifications:
The major hardware components which are used in project are listed and discussed below.
• DC brushless motor
• Propeller • Radio receiver • E.S.C
• Servo motor • Push rod
• Controller
6.3.1 DC Brushless Motor:
DC brushless motor is used is used in moving propeller. Because of its high speed and efficiency it is preferred over brush motors. Although it is expensive with respect to other motors but the cost is compensated with the durability and reliability of the motor. Carbon brush motors have a moving rotor and permanent magnet stator. Rotor is supplied with electric power and it makes electromagnet. Poles of electromagnet repel and attract each other and rotor starts rotating. Output is taken from rotor. Carbon brushes causes friction and voltage drop which ultimately reduces efficiency of the motor.
In case of dc brushless motors the rotor is fixed and stator is made rotating. Rotors are permanent electromagnet and vice versa. Elimination of carbon brushes reduces voltage drop and increases output and also enhances the working efficiency and life of the motor.
Rpm per volt= 2200
Voltage supply= 11V
Rpm with 11V = 2200*11= 24200
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Figure 6.2 DC Brushless motor
6.3.2 Propeller:
A 6*4” propeller is used for generation of thrust. It generates thrust of 1kg. Speed of propeller varies the amount of thrust. Propeller is placed 14” above the ground surface. It helps a lot in the stability of plane. In the previous designed model propeller was on the top. That model was creating problem of stability.
Figure. 6.3 Propeller.
6.3.3 Radio Transmitter/Receiver:
Radio antenna receives the electromagnetic signal on the VTOL body. Signal is converted into tiny current and then transmitted to receiver. This information is demodulated and then control signal is sent to components. It is working on the frequency of 2.4 GHz. It has range of approximately 600m.
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Figure 6.4 Radio Transmitter/Receiver
6.3.4 Electronic Speed controller (E.S.C):
Electronic speed controller is used to limit the current for dc motor and control its speed.
Fig. 6.5.
.
6.3.5 Servo Motor:
Servo motors are used for controlled movement. These motors have a feedback sensor. Using close path system error is generated on the basis of current and input position. We have used two 9g servos in out project. These servos have 3 wires. One wire for Vcc second wire for ground and the third wire for input signal. This signal defines the position and angle of the servo.
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Figure 6.6 Servo motor
6.3.6 Push Rod:
We have used a push rod of 1mm. Its length is 1 foot and it is made of steel. It is used to connect ailerons with the stabilizer. Normally it is used when we have large wings of plane and the distance between servo and stabilizer is also large.
Figure 6.7 Push Rod
6.3.7 Controller:
We have used Arduino Atmega 2560 microcontroller. It is complete board having 54 digital pins and 16 analog pins. 16 MHz crystal is used in it. There are special communication and power pins. There are two pins for I2C interface. These are special communication pins used for some of sensors. We have connected 10DOF with these pins. It has a USB interface and a dc supply port. Voltage can either be provided by computer to USB port or DC battery with regulator can be used. We have used a voltage regulator LM7805 which converts 9V to 5V.
Its program is written in C language in its own software.
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Figure 6.8 Arduino Controller
6.4 Software Used:
We have used three software’s for simulation purpose.
• Arduino • Lab view
• Hyper terminal • X-CTU
6.4.1 Arduino:
Arduino software is used for writing the program of sensors and uploading it on the controller. We have installed sensors related libraries in it and then we have written our code according to desired data. Syntax of coding in Arduino software involves two main parts.
One is called Void Setup and second is called Void Loop. In void setup only functions are initialized one time and integers may be declared. But in void loop functions are executed repeatedly .
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Figure 6.9Arduino Software
6.4.2 Lab view:
Lab view is used for graphical representation of real world data. It is discusses in details in chapter no 5.
6.4.3 Hyper Terminal:
Hyper terminal is used for serially monitoring the data. However it can be accomplished using Arduino software but sometimes Arduino serial monitor causes trouble. Using hyper terminal data can be transmitted as well as received on serial port.
6.4.4 X-CTU:
We have also worked on X-CTU. It is special software for configuration of Xbee module. Data can be transmitted and received using this software. There is option of selecting AT or API mode of data transmission in this software.
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6.4.4.1 AT Command Mode:
In AT command mode data is transmitted in the form of single bits. This transmission method is slow and it may cause delay.
6.4.4.2 API Command Mode:
In API mode the data is sent from Xbee to Xbee in the form of packets. This is a fast way of sending data and it also reduces the probability of errors.
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CHAPTER 7
REUSLTS AND ANALYSIS
And Conclusion
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7 Hardware/Software Results:
We have attached gyro sensor, accelerometer, GPS and Barometric pressure sensor with our VTOL. All of these sensors are working properly and giving accurate reading. Xbee was also giving data properly. We tested all the equipment and it was in working condition. Here is a picture taken of the data received at ground station.
Fig. 7.1.
And here is another picture of data received of GPS. It was checked on internet by giving the values of latitude and longitude and found correct.
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Fig .7.2.
Our software of Lab view and Hyper Terminal gave accurate readings.
7.1 Comparison with Initial Goal:
At the completion of project we have just covered all of our goals. Plane took successful vertical flight and landing. All the sensors were working properly. It was completely controlled structure. In our first structure there was a technical fault. When propeller speed was increased plane started rotating. It was not stable. Then we designed this structure with the help of our supervisor.