Quadrotor Unmanned Aerial Vehicle (UAV)

TABLE OF CONTENTS

TABLE OF CONTENTS

LIST OF TABLES

LIST OF FIGURES

ABSTRACT

Chapter One
1.1 History
1.2 Introduction
1.3 Design Proposal
1.4 Motivation
1.5 UAV Types
1.6 Scope
1.7 Description of project
1.8 Significance of project

Chapter Two
2.1 Background
2.2 Overview
2.3 Flight Control
2.4 Quad rotor Services

Chapter Three
3.1 Quad rotor Model
3.2 Basic concepts
3.3 Quadrotor Structure
3.4 System Integration
3.5 Flight Dynamics
3.6 Assumption

Chapter Four
4.1 Hardware Components
4.2 Frame
4.3 Design of Frame
4.4 Brushless Motors
4.5 Electronic Speed Controllers
4.6 Power Supply System
4.7 LiPo Battery
4.8 LM
4.9 LD1117V
4.10 LM
4.11 Flight Stability Sensors
4.12 ATmega
4.13 Microcontroller Information
4.14 Camera
4.15 Wireless Communication

Chapter Five
5.1ORCAD
5.2 Keil µVision
RESULT AND DISCUSSION

Chapter Six
6.1 APPLICATION

Chapter Seven
7.1 CONCLUSION
7.2 FUTURE ENHANCEMENT
7.3 DISCUSSION AND CONCLUSIONS

References

LIST OF TABLES

3.1 Comparison of different grades in last one year

4.1 Comparison of different grades in last two year

4.2 Comparison of different grades in last three year

LIST OF FIGURES

1.1 Comparison of East, West and North in last four years

ABSTRACT

Inertial navigation systems are used in many situations where the use of an external reference to measure position is impractical or unreliable. Typical inertial navigation systems used in aeronautics and marine applications are highly advanced pieces of equipment costing a lot of money. However, inexpensive accelerometers and angular rate sensors (gyros) can be used to make a far less accurate inertial navigation unit .Programming a complex robotic system has typically required a large amount of time from an interdisciplinary team of electronic engineers, electrical engineers, and control theorists. This broad set of skills is required largely because single high-level action requires thousands of decisions at deferent points in time based on the robot’s sensor input and position. Reinforcement learning promises to simplify the otherwise time-consuming process of programming a robot’s desired behavior by allowing the programmer to specify what action the robot should perform without ever detailing how it should perform the action. This abstraction is especially beneficial when controlling a robot with multiple actuators such as aerial robot moving through a dynamic environment.

Chapter One

1.1 History

Research into the initial development of quad rotors began in the early twentieth century.

One of the first engineers to attempt to design a quad rotor was Etienne Oemichen. Oemichen began his research in 1920 with the completion of the Oemichen No.1. This design consisted of four rotors and a 25 Horsepower motor; however, during tests flights the Oemichen No.1 was unable to obtain flight. Two years later Oemichen completed his second design; the Oemichen No.2. His second design consisted of four rotors and eight propellers along with a 125 Horsepower motor. Five of the propellers were used to achieve stable flight while two were used for propulsion and the final propeller being used to steer the aircraft. In April of 1914, the Oemichen No.2 achieved an FAI distance record for helicopters of 360m, which the Oemichen No.2 broke with a distance of 525m. While Oemichen had begun working on his early designs in France, Dr. George de Bothezat and Ivan Jerome began their own research in January 1921 for the United States Army Air Corps. They completed their design in mid-1922, and the first test flight took place in October of 1922 in Dayton, Ohio. Bohezat‟s and Jerome‟s design weighed around 1700 kg at the time of takeoff and consisted of four six-bladed rotors along with a 220-HP motor. After many tests, the quad rotor was only able to achieve a maximum flight time of 1 minute 42 seconds and maximum height of 1.8 meters.

Following the research of Oemichen, Bothezat and Jerome, other researchers have attempted to create their own successful vertical flying machines. One such was being the Convert wings Model “A” quad rotor. The Convert wings Model “A” quad rotor was designed and built in the mid 1950‟s with civil and military purposes in mind. This particular quad rotor 5 consisted of four rotors, two motors as well as wings. Due to lack of interest, however, the Convert wings Model “A” quad rotor was never mass produced. Currently Bell Helicopter Textron and Boeing Integrated Defense Systems are doing joint researched on the development of the Bell Boeing Quad Tilt Rotor. The initial design consists of four 50-foot rotors powered by V-22 engines. The main role of the Bell Boeing Quad Tilt Rotor will be that of a cargo helicopter with the ability to deliver pallets of supplies or also deploy paratroopers. The first wind tunnel tests were completed in 2006 and the first prototype is expected to be built in 2012

1.2 Introduction

Quad rotor helicopters are one form of aerial vehicles that offer an excellent balance between maneuverability and stability. Our project is to design and build a quad-rotor UAV. Our proposed design is for a lightweight, nimble craft that can be operated both indoors and out. The project poses particular challenges in terms of weight reduction and controllability. Thus, weight reduction of all components is essential in order to allow for sufficient lift force. The controls system for such a craft is also complex, as it requires the synchronization of four individual motors. These motors must be closely controlled in order to account for variations between the motors (one motor slightly more powerful than the others will upset the equilibrium of the craft), and in order to effectively dampen external disturbances Quad rotors are symmetrical vehicles with four equally sized rotors at the end of four equal length rods. Unlike their counter parts, quad rotors make use of multiple rotors allowing for a greater amount of thrust and consequently a greater amount of maneuverability. Also, the quad rotors symmetrical design allows for easier control of the overall stability of the aircraft a quad rotor is supported by four horizontally-oriented blades surrounding a central chassis that houses the vehicle’s electronics and, potentially, its payload. By using four horizontal blades instead of one horizontal blade and one vertical blade, a quad rotor is capable of moving, strafing, and turning in three-dimensional space by altering the relative speeds of its rotors.

1.3 Design Proposal

Our project showcases important control capabilities which allow for autonomous

balancing of a system which is otherwise dynamically unstable. A quad-rotor poses a more challenging control problem than a single-rotor or dual-rotor inline helicopter because the controls demands include accounting for subtle variations which exist between the motors and 4 cause each motor to provide a slightly different level of lift. In order for the quad-rotor craft to be stable, the four motors must all provide the same amount of lift, and it is the task of the control system to account for variations between motors by adjusting the power supplied to each one. We supposed the control of a quad-rotor craft as a valuable challenge to pursue. The benefits of such a craft warrant the design challenges, as a quad-rotor craft is more efficient and nimble than a single-rotor craft. Unlike a single-rotor craft, which uses a second, smaller vertical propeller to change direction, the quad-rotor craft’s directional motion is generated by the same

Four motors that are providing lift. Also, the quad-rotor can change direction without having to reorient itself – there is no distinction between front and back of the craft. In the quad-rotor, every rotor plays a roll in direction and balance of the vehicle as well as lift, unlike the more traditional single rotor helicopter designs in which each rotor has a specific task - lift or directional control - but never both.

1.4 Motivation

Although the quad rotor has the advantages in :

- Mechanical construction
- Widely used in many of the fields and application
- Small payload
- Reduced processing power
- Camera Ability

1.5 UAV Types

- Target and decoy - providing ground and aerial gunnery a target that simulates an enemy aircraft or missile Reconnaissance
- Providing battlefield intelligence Combat - providing attack capability for high-risk missions Research and development - used to further develop UAV technologies to be integrated into field deployed UAV aircraft Civil and Commercial UAVs
- UAVs specifically designed for civil and commercial applications.

1.6 Scope

Unmanned aerial vehicles (UAVs) are crafts capable of flight without an onboard pilot. They can be controlled remotely by an operator, or can be controlled autonomously via preprogrammed flight paths. Such aircraft have already been implemented by the military for recognizance flights. Further use for UAVs by the military, specifically as tools for search and rescue operations, warrant continued development of UAV technology. A quad-rotor helicopter is an aircraft whose lift is generated by four rotors.

Control of such a craft is accomplished by varying the speeds of the four motors relative to each other. Quad-rotor crafts naturally demand a sophisticated control system in order to allow for balanced flight. Uncontrolled flight of a quad-rotor would be virtually impossible by one operator, as the dynamics of such a system demand constant adjustment of four motors simultaneously. The goal of our project was to design and construct a quad-rotor vehicle capable of indoor and outdoor flight and hover. Through the use of an integrated control system, this vehicle would be capable of autonomous operation, including take-off, hover, and landing

1.7 Description of project

The human pilot in an aircraft can direct the aircraft to a region of interest after taking ground observations, whereas in an unmanned aircraft there is no need of a pilot. The aircraft is remotely operated wirelessly with the operator or user held at a specific distance. Sensors, cameras and different devices are mounted on the UAV to serve as a safe flight. It then also can be used for surveillance purpose.

Images are received to the ground operator who interprets it and reacts accordingly

1.8 Significance of project

Unmanned Aerial Vehicles (UAV’s) has received widespread attention in recent years. These UAV’s can be used in many applications such as surveillance, information gathering, suppression of enemy defenses, air to air combat, and facilities etc.

Chapter Two

2.1 Background

A quad rotor is an aircraft that is lifted and propelled by four rotors. Quad rotors are classified as rotorcraft, as opposed to fixed-wing aircraft, because their lift is derived from four rotors. Unlike most helicopters, quad rotors use fixed-pitch blades, whose rotor pitch does not vary as the blades rotate; control of vehicle motion is achieved by varying the relative speed of each rotor to change the thrust and torque produced by each.

There are two generations of quad rotor designs. The first generation quad rotors were designed to carry one or more passengers. These vehicles were among the first successful heavier-than-air vertical takeoff and landing vehicles. However, early prototypes suffered from poor performance, and latter prototypes required too much pilot work load, due to poor stability augmentation.

The more recent generation of quad rotors are commonly designed to be unmanned aerial vehicles (UAVs). These vehicles use an electronic control system and electronic sensors to stabilize the aircraft. With their small size and agile maneuverability, these quad rotors can be flown indoors as well as outdoors.

The advantages of the current generation of quad rotors, versus comparably-scaled helicopters, are as follows. First, quad rotors do not require mechanical linkages to vary the rotor blade pitch angle as they spin. This simplifies the design and maintenance of the vehicle. Second, the use of four rotors allows each individual rotor to have a smaller diameter than the equivalent helicopter rotor, allowing them to possess less kinetic energy during flight. This reduces the damage caused should the rotors hit anything. For small-scale UAVs, this makes the vehicles safer for close interaction. Some small-scale quad rotors have frames that enclose the rotors, permitting flights through more challenging environments, with lower risk of damaging the vehicle or its surroundings.

Due to their ease of both construction and control, quad rotor aircraft are frequently used as amateur model aircraft projects.

2.2 Overview

The quad rotor is very well modeled with a four rotors in a cross configuration. This cross structure is quite thin and light, however it shows robustness by linking mechanically the motors (which are heavier than the structure). Each propeller is connected to the motor through the reduction gears. All the propellers axes of rotation are fixed and parallel. Furthermore, they have fixed-pitch blades and their air flows points downwards (to get an upward lift). These considerations point out that the structure is quite rigid and the only things that can vary are the propeller speeds. In this section, neither the motors nor the reduction gears are fundamental because the movements are directly related just to the propellers velocities.

Abbildung in dieser Leseprobe nicht enthalten

Figure 2.1

The others parts will be taken into account in the following sections. Another neglected component is the electronic box. As in the previous case, the electronic box is not essential to understand how the quad rotor flies. It follows that the basic model to evaluate the quad rotor movements it is composed just of a thin cross structure with four propellers on its ends. The front and the rear propellers rotate counter-clockwise, while the left and the right ones turn clockwise. This configuration of opposite pair’s directions removes the need for a tail rotor.

2.3 Flight Control

Each rotor produces both a thrust and torque about its center of rotation, as well as a drag force opposite to the vehicle's direction of flight. If all rotors are spinning at the same angular velocity, with rotors one and three rotating clockwise and rotors two and four counterclockwise, the net aerodynamic torque, and hence the angular acceleration about the yaw axis is exactly zero, which implies that the yaw stabilizing rotor of conventional helicopters is not needed. Yaw is induced by mismatching the balance in aerodynamic torques (i.e., by offsetting the cumulative thrust commands between the counter-rotating blade pairs).Angular accelerations about the pitch and roll axes can be caused separately without impacting the yaw axis. Each pair of blades rotating in the same direction controls one axis, either roll or pitch, and increasing thrust for one rotor while decreasing thrust for the other will maintain the torque balance needed for yaw stability and induce a net torque about the roll or pitch axes. This way, fixed rotor blades can be made to maneuver the quad rotor vehicle in all dimensions. Translational acceleration is achieved by maintaining a non-zero pitch or roll angle

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Figure 2.2

2.4 Quad rotor Services

- The quad rotor can do the following abilities:
- Communicate Wirelessly
- Wireless Control
- Camera
- Payload
- Hovering up to 30minutes
- Speed Variable Motors
- 6-way Remote Control

Chapter Three

3.1 Quad rotor Model

Quad rotor helicopters have become increasingly popular as unmanned aerial vehicle (UAV) platforms. These vehicles have 4 identical rotors in 2 pairs spinning in opposite directions, and possess many advantages over standard helicopters in terms of safety and efficiency at small sizes.

The first section

(3.2: Basic concepts) shows the main idea of the quad rotor dynamics and describes intuitively which movements are allowed and how it manages to perform stationary flight (hovering).

(3.3: Quad rotor Structure)

(3.4: System Integration)

(3.5: Flight Dynamics)

The last section (3.6: Assumption).

Abbildung in dieser Leseprobe nicht enthalten

Figure 3.1

3.2 Basic concepts

The quad rotor is very well modeled with a four rotors in a cross configuration.

This cross structure is quite thin and light, however it shows robustness by linking

mechanically the motors (which are heavier than the structure). Each propeller

is connected to the motor through the reduction gears. All the propellers axes

of rotation are fixed and parallel. Furthermore, they have fixed-pitch blades and

their air flows points downwards (to get an upward lift). These considerations

point out that the structure is quite rigid and the only things that can vary are the propeller speeds.

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