The application of unmanned aerial vehical(UAV) and micro aerial vehical(MAV) can apply to variety of an area such as rescue mission, military, film making, agriculture and others.
‘ Quadcopter or Quadrotor aircraft is one of the UAV that are major focuses of active researches in recent years.
‘ Quadcopter operated by thrust that produce by four motors that attached to it body.
‘ Using a four brushless motor Quadcopter design we are able to change directions, elevation, and tilt rapidly by simply manipulating how much voltage goes into the motors while the quadcopter is in the air.
‘ Quadcopter has advantages over the conventional helicopter where the mechanical design is simpler.
‘ Besides that, Quadcopter changes direction by manipulating the individual propeller’s speed and does not require cyclic and collective pitch control.
‘ The system itself is powered by a high capacity lithium polymer battery capable of a high discharge rate, allowing for sustained flights and adequate power supplied to the system at all times.
‘ Quad-rotor system that uses an accelerometer and gyroscope to provide stability while in flight.
1.1 : PROBLEM STATEMENT
The main problem in Quadcopter is the balancing and stability system. Most of Quadcopter will be unbalance and lost stability in case there are disturbance direct on it such as wind. In this research, to solve above problem the full sustem of Quadcopter is design and construct.
1.2: PROJECT OBJECTIVES
The objectives of this project are:
a) To design Quadcopter that can control wireless base on computer.
b) To equip Quadcopter with stereo camera to display video or photos.
c) To test the performance of designed Quadcopter.
d) To make air vehicle system that must fit in a rucksack carried by a single person.
1.3 : PROJECT SCOPES/CONSTRAINS
The scopes include the weather condition, distance and space:
a) Quadcopter only can operate in sunny day or dry condition.
b) Quadcopter operate distance not more than 100m in eye sight from the wireless receiver.
c) Quadcopter is control by Arduino base microcontroller.
d) Quadcopter is operated by brushless motor control by electronic speed controller.
Chapter 2 : LITERATURE REVIEW
2.1: INTRODUCTION
In order to run ‘Wireless control Quadcopter with Stereo Camera and self balancing System’ research, several theoretical and techniques are need review through previous related research report. The review includes the technology development and control method that used in Quadcopter.
Summarize and comparison of Quadcopter previous work.
Table:1: Literature review
No. Research title Advantages Disadvantages
1 3-DOF attitude control free flying vehicle Simple and basic of controller design. Limited degree of freedom (Only 3-DOF applies).
2 Nonlinear model and non linear control strategy for a 6-DOF Quadcopter aerial robot Compensate the initial error, stabilize roll, pitch and yaw angles and maintain them at zero. Only design for balancing during hover position of Quadcopter.
3 Control of Quadcopter by visual tracking using stereo camera The tracking system is highly transportable, easy to setup. Sensitive to light and not suitable to use at high illumination area.
4 Intelligent fuzzy controller of Quadcopter Fuzzy controller has fast dynamic response and small overshoot Controller design is to complex
5 Analyze the dynamic characteristics and PID controller performance of a Quadcopter Strong adaptive ability The system will be unstable if the value Kp, Ki and Kd is not consistent.
Chapter 3 : METHODOLOGY
3.1 : INTRODUCTION
This will divide into two phases. The first phase is understanding the Quadcopter structure and it basic mathematical modeling. The last phase is deals with design and costruction of the Quadcopter. It will be built by splitting the design into different component where by each component will be tested to ensure its working properly. This step is to minimize the risk of accidents which will lead to increasing number of component cost.
3.2 : FLOW CHART
Flow chart of Quadcopter design is described in figure below:
3.3 : QUADCOPTER MOVEMENT MECHANISM
Quadcopter can described as a small vehicle with four propellers attached to rotor located at the cross frame. This aim for fixed pitch rotors are used to control the vehicle motion. The speeds of these four rotors are independent. By independent, pitch, roll and yaw attitude off Quadcopter are shown in figure.
Quadcopter have four inputs force and basically the thrust that produced by the propeller that connect to the motor. The motion of Quadcopter can control through fix the thrust that produced. These thrust can control by the speed of each rotor.
3.3.1 : TAKE-OFF AND LANDING MOTION MECHANISM
Take-off is movement of Quadcopter that lift up from ground to air and landing position is versa of take-off position. Take-off (landing) motion is control by increasing (decreasing) speed of four rotors simultaneously which means changing the vertical motion. Figure illustrated the take-off and landing motion of Quadcopter respectively.
3.3.2 : FORWARD AND BACKWARD MOTION
Forward (backward) motion is control by increasing (decreasing) speed of rear (front) rotor. Decreasing (increasing) rear (front) rotor speed simultaneously will affect the pitch angle of the Quadcopter. The forward and backward motion of Quadcopter are represented in figure.
3.3.3 : LEFT AND RIGHT MOTION
For left and right motion, it can control by changing the yaw angle of Quadcopter. Yaw angle can control by increasing (decreasing) counter-clockwise rotors speed while decreasing (increasing) clockwise rotor speed. Figure shows the right and left motion of Quadcopter.
Chapter 4 : QUADCOPTER COCEPTS
4.1 : QUADCOPTER THEORY
Our Quad-copter uses four propellers, each controlled by its own motor and electronic speed controller. Using accelerometers we are able to measure the angle of the Quad-copter in terms of X, Y, and Z and accordingly adjust the RPM of each motor in order to self-stabilize its self. The Quad-copter platform provides stability as a result of the counter rotating motors which result in a net moment of zero at the center of the Quad-copter.
Figure 12 Quadcopter
Using this principle we are able to adjust the speed (RPM as a function of the voltage provided to the motor) of each individual motor in order to correctly manipulate Quad-copter’s yaw, pitch, and roll. Pitch and roll can be controlled by changing the speed of the appropriate motors, while yaw control involves delicate balancing of all four motor functions in order to change the moment force applied to the quad.
Figure.13 pitch, roll and yaw for aircraft
YAW ANGLE: The angle between an aircraft’s longitudinal axis and its line of travel, as seen from above.
PITCH ANGLE: The angle between an object’s rotational axis, and a line perpendicular to its orbital plane.
ROLL ANGLE: The angle of rotation of a vehicle about its longitudinal axis.
Figure. 14 direction of rotation of motors
As you can see from the above given figure, two of the motors i.e. motor 1 and 3 are rotating in a clockwise direction and the other two motors i.e. motor 2 and 4 are rotating in anti-clockwise direction so as to ensure the perfect balance at the center of the quad-copter.
Unlike common helicopters that have variable pitch angle, the quad copter obtains the expected speed by its fix pitch rotors whose speed is variable. The vertical movement of quad copter could be realized by adjustments of the speeds of all four rotors at the same time. The movement along the X direction depends on the inclination on Y whose angle could be adjust by slowing down the speeds of rotors 1 and 2, speeding up rotors 3 and 4.The inclination also generate the acceleration along X direction.
4.2 : MODULATION
Pulse width modulation:-
Pulse width modulation is the way of simulating an analog output by varying HIGH and LOW signals at intervals proportional to the value. Width of each pulse varies according to the amplitude of the analog signals.
Figure.15 Pulse width modulation
Pulse-width modulation, or pulse-duration modulation, is a commonly used technique for controlling power to inertial electrical devices, made practical by modern electronic power switches. The term duty cycle describes the proportion of ‘on’ time to the regular interval or ‘period’ of time; a low duty cycle corresponds to low power, because the power is off for most of the time. Duty cycle is expressed in percent, 100% being fully on.
The average value of voltage (and current) fed to the load is controlled by turning the switch between supply and load on and off at a fast pace.
Duty cycle:-
In a periodic event, duty cycle is the ratio of the duration of the event to the total period.
Figure.16 Duty cycle
Pulse position modulation:-
Pulse position modulation is a form of signal modulation in which M message bits are encoded by transmitting a single pulse in one of 2M possible time ‘ shifts. This is repeated every T seconds, such that transmitted bit rate is M/T bits per second.
Pulse position modulation (PPM) is a pulse modulation technique that uses pulses that are of uniform height and width but displaced in time from some base position according to the amplitude of the signal at the instant of sampling.
Figure.17 Pulse position modulation
‘ PWM to PPM conversion in a Quadcopter:-
PWM refers to a pulse width modulation signal, where the width of each pulse changes according to the amplitude of an analog signal. PPM on the other hand refers to a pulse position modulation signal, where the width of each pulse remains the same, but each pulse is displaced by a certain position based on the analog signal amplitude. The basic need for conversion of a PWM signal received from a transmitter into a PPM signal arises due to the fact that the main controller board used (ArduIMU) on a quad-copter cant process a PWM signal and hence a converter is required to convert a PWM signal to a PPM signal. The conversion of a PWM signal to a PPM signal is as explained in the below figure.
Figure.18 PWM to PPM conversion
Chapter 5 : COMPONENTS
Components that required is divided into two parts that are hardware and software. Figure shows the block diagram of quadcopter which includes all major components used in it. The signal is produced by Arduino Uno, to control four brushless motor of Quadcopter through ESC.
Figure.19 block diagram of the system
The working of system is as follows:
When the system is switched on, the receiver starts listening to the transmitting frequency(here 2.4 GHz).The transmitter gives commands for throttle. Yaw, pitch and roll which is interpreted by the 4 channels of the receiver used. The PWM signals are forwarded to PWM to PPM converter. This PPM signal is send to the controller(accelerometer and gyroscope). The PPM signal is processed by controller and gives 4 PWM outputs for 4 motors. This PWM signals are given to Electronic speed controller which also receive a battery connection each of 11 volts. The ESC switches the supply across the motor coils to run it at a specified speed. Accelerometer and Gyroscope are build on the Arduino which balances the quadcopter in air.
5.1 : PROPELLERS
A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and air or water is accelerated behind the blade.
Aircraft propellers convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal. The most modern propeller designs use high-technology composite materials.
5.1.1: AIRFOIL
An airfoil or aero foil is the shape of a wing or blade (of a propeller, rotor or turbine).
Figure. 20 Air speed variations on an airfoil
An aerofoil is shaped so that air flows faster over the top than under the bottom. There is, therefore, a greater pressure below the aerofoil than above it. This difference in pressure produces the lift.
Lift coefficient is a dimensionless coefficient that relates the lift generated by an aerodynamic body such as a wing or complete aircraft, the dynamic pressure of the fluid flow around the body, and a reference area associated with the body.
Propellers used:-
We have used two blades, 9??4.7 pitch rotating and counter rotating propellers. We are using two different kinds of blades one rotating in clockwise directions and other rotating in anti-clockwise direction, thus producing force in opposite directions.
Figure. 21 two blade PROP 9??4.7
5.2 : RADIO TRANSMITTER AND RECEIVER
Transmitter:-
In electronics and telecommunications a radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves. The term transmitter is usually limited to equipment that generates radio waves for communication purposes; or radio location, such as radar and navigational transmitters. A transmitter can be a separate piece of electronic equipment, or an electrical circuit within another electronic device. A transmitter and receiver combined in one unit is called a transceiver.
The term transmitter is often abbreviated ‘XMTR’ or ‘TX’ in technical documents. The purpose of most transmitters is radio communication of information over a distance. The information is provided to the transmitter in the form of an electronic signal, such as an audio (sound) signal from a microphone, a video (TV) signal from a TV camera, or in wireless networking devices a digital signal from a computer. The transmitter combines the information signal to be carried with the radio frequency signal which generates the radio waves, which is often called the carrier. This process is called modulation.
A radio transmitter is an electronic circuit which transforms electric power from a battery or electrical mains into a radio frequency alternating current, which reverses direction millions to billions of times per second. The energy in such a rapidly-reversing current can radiate off a conductor (the antenna) as electromagnetic waves (radio waves).
Receiver:-
A radio receiver is an electronic circuit that receives its input from an antenna, uses electronic filters to separate a wanted radio signal from all other signals picked up by this antenna, amplifies it to a level suitable for further processing, and finally converts through demodulation and decoding the signal into a form usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc. Demodulation is the act of extracting the original information-bearing signal from a modulated carrier wave. A demodulator is an electronic circuit that is used to recover the information content from the modulated carrier wave.
The receiver in information theory is the receiving end of a communication channel. It receives decoded messages/information from the sender, who first encoded them. Sometimes the receiver is modeled so as to include the decoder. Real-world receivers like radio receivers cannot be expected to receive as much information as predicted by the noisy channel coding theorem.
5.2.1 : FLYSKY 6 CHANNEL TRANSMITTER
HKT6A transmitter is used is 6 channel, FM modulating with a 2.4 GHz frequency band, the frequency at which it transmits the modulated signal. The signal transmitted by the transmitter is received by a HKT6A receiver which de-modulates the signal to get the original signal.
Specifications:-
‘ 6 channel
‘ FM modulation type
‘ 2.4 GHz frequency band
‘ Power resource 1.5 v * 8 ‘AA’ battery
‘ GFSK program type
‘ LED voltage display
‘ Weight : 575g
‘ Size : 189*97*218mm
‘ 26mm antenna length
5.2.2 : MODES OF A TRANSMITTER
Modes of a transmitter hk-t6a specify the working of the transmitter, where the left gauge upward movement specifies the throttle necessary for the lift. The left gauge left-right movement specifies the yaw angle. Further the right gauge upward movement is for controlling the pitch and the left-right movement to control the roll. All the above explained specifies the modes of transmitter necessary for controlling the quad-copter in the air. The mode has been specified in the figure.
Figure.22 Flysky 6 channel transmitter ‘ mode of operation
Figure 23 Flysky 6 channel transmitter
A radio transmitter is an electronic circuit which transforms electric power from a battery or electrical mains into a radio frequency alternating current, which reverses direction millions to billions of times per second. The energy in such a rapidly-reversing current can radiate off a conductor (the antenna) as electromagnetic waves (radio waves). Transmitter is used to modulate a original signal onto the carrier wave, thus generating radio waves that are transmitted to the receiver, which upon receive De-modulates the signal and retrieve the original intended signal.
5.2.3 : FLYSKY 6 CHANNEL RECEIVER
Specifications:-
‘ 6 CHANNEL
‘ FM MODULATION TYPE
‘ 2.4GHZ FREQUENCY BAND
‘ POWER RESOURCE 1.5V * 4 ”AA” BATTERY
‘ GFSK PROGRAM TYPE
‘ WEIGHT : 12g
‘ SIZE : 45*23*13.5 mm
””””””””””””””””””””””””””””’Figure.24 Flysky 6 channel receiver
5.3 : GYROSCOPE
A gyroscope is a device for measuring or maintaining orientation, based on the principles of conservation of angular momentum. The first commercially available surface-micro machined angular rate sensors with integrated electronics, they are smaller’with lower power consumption, and better immunity to shock and vibration’ than any gyros having comparable functionality. This genuine breakthrough is possible only because of the Analog Devices proprietary integrated micro electro-mechanical system (iMEMS) process, proven by use in millions of automotive accelerometers.
Gyroscopes are used to measure angular rate’how quickly an object turns. The rotation is typically measured in reference to one of three axes: yaw, pitch, or roll.
5.4 : ACCELEROMETER
An accelerometer is a device that measures the proper acceleration of the device. This is not necessarily the same as the coordinate acceleration (change of velocity of the device in space), but is rather the type of acceleration associated with the phenomenon of weight experienced by a test mass that resides in the frame of reference of the accelerometer device. For an example of where these types of acceleration differ, an accelerometer will measure a value when sitting on the ground, because masses there have weights, even though they do not change velocity. However, an accelerometer in gravitational free fall toward the center of the Earth will measure a value of zero because, even though its speed is increasing, it is in an inertial frame of reference, in which it is weightless.
5.4.1 : PHYSICAL PRINCIPLES
An accelerometer measures proper acceleration, which is the acceleration it experiences relative to free-fall and is the acceleration felt by people and objects. Put another way, at any point in space-time the equivalence principle guarantees the existence of a local inertial frame, and an accelerometer measures the acceleration relative to that frame. Such accelerations are popularly measured in terms of g-force.
5.4.2 : STRUCTURE
Conceptually, an accelerometer behaves as a damped mass on a spring. When the accelerometer experiences acceleration, the mass is displaced to the point that the spring is able to accelerate the mass at the same rate as the casing. The displacement is then measured to give the acceleration.
Figure. 25 Working of accelerometer
Capacitive accelerometers typically use a silicon micro-machined sensing element. Their performance is superior in the low frequency range and they can be operated in servo mode to achieve high stability and linearity.
5.5 : MOTORS
DC motors:-
A DC motor is an electric motor that runs on direct current (DC) electricity. In any electric motor, operation is based on simple electromagnetism. A current-carrying conductor generates a magnetic field; when this is then placed in an external magnetic field, it will experience a force proportional to the current in the conductor, and to the strength of the external magnetic field. As you are well aware of from playing with magnets as a kid, opposite (North and South) polarities attract, while like polarities (North and North, South and South) repel. The internal configuration of a DC motor is designed to harness the magnetic interaction between a current-carrying conductor and an external magnetic field to generate rotational motion.
A dc motor can be broadly classified into two distinguished types of motors namely :
‘ Brushed dc motor
‘ Brushless dc motor
As per our project we will be concentrating more on the concept of brushless dc motor.
5.5.1 : BRUSHED DC MOTOR
A brushed DC motor is an internally commutated electric motor designed to be run from a DC power source. The brushed dc electric motor generates torque directly from DC power supplied to the motor by using internal commutation, stationary permanent magnets, and rotating electrical magnets.
Like all electric motors or generators, torque is produced by the principle of Lorentz force, which states that any current-carrying conductor placed within an external magnetic field experiences a torque or force known as Lorentz force.
When a current passes through the coil wound around a soft iron core, the side of the positive pole is acted upon by an upwards force, while the other side is acted upon by a downward force. According to Fleming’s left hand rule, the forces cause a turning effect on the coil, making it rotate. To make the motor rotate in a constant direction, ‘direct current’ commutators make the current reverse in di rection every half a cycle (in a two-pole motor) thus causing the motor to continue to rotate in the same direction.
Figure.26 Brushed DC motor
When a current passes through the coil wound around a soft iron core, the side of the positive pole is acted upon by an upwards force, while the other side is acted upon by a downward force. According to Fleming’s left hand rule, the forces cause a turning effect on the coil, making it rotate. To make the motor rotate in a constant direction, ‘direct current’ commutators make the current reverse in di rection every half a cycle (in a two-pole motor) thus causing the motor to continue to rotate in the same direction.
A problem with the motor shown above is that when the plan of the coil is parallel to the magnetic field ‘ i.e. when the rotor poles are 90 degrees from the stator poles ‘ the torque is zero. In the pictures above, this occurs when the core of the coil is horizontal ‘ the position it is just about to reach in the last picture on the right. The motor would not be able to start in this position.
5.5.2 : BRUSHLESS DC MOTOR
Brushless DC motors (BLDC motors, BL motors) also known as electrically commutated motors (ECMs, EC motors) are synchronous electric motors powered by direct ‘ current (DC) electricity and electronic commutation systems, rather mechanical commutators and brushes.
The current-to-torque and frequency-to-speed relationships of BLDC motors are linear. BLDC motors may be described as stepper motors, with fixed permanent magnets and possibly more poles on the rotor than the stator, or reluctance motors. The latter may be without permanent magnets, just poles that are induced on the rotor then pulled into alignment by timed stator windings. However, the term stepper motor tends to be used for motors that are designed specifically to be operated in a mode where they are frequently stopped with the rotor in a defined angular position; this page describes more general BLDC motor principles, though there is overlap. Now the movement of the magnet in the center depends on the direction of flow of current in the coil as shown in the above figure. The continuous movement of the magnet is ensured by Left hand rule for the coils.
Figure.27 Brushless DC motor
5.5.2(a) : PROGRAM ‘For single motor
#include <Servo.h>
Servo bldc;
void setup()
{
Serial.begin(9600);
bldc.attach(9);
//bldc.writeMicroseconds(1500);
}
void loop()
{
int v = analogRead(A0);
v=map(v,0,1024,1000,2000);
bldc.write(v);
}
5.5.2(b) :For all Four motors
#include <Servo.h>
#define MAX_SIGNAL 2000
#define MIN_SIGNAL 1000
#define MOTOR_PIN 9
Servo motor;
void setup()
{
Serial.begin(9600);
Serial.println("Program begin…");
Serial.println("This program will calibrate the ESC.");
motor.attach(MOTOR_PIN);
Serial.println("Now writing maximum output.");
Serial.println("Turn on power source, then wait 2 seconds and press any key.");
motor.writeMicroseconds(MAX_SIGNAL);
// Wait for input
while (!Serial.available());
Serial.read();
// Send min output
Serial.println("Sending minimum output");
motor.writeMicroseconds(MIN_SIGNAL);
}
void loop()
{
if(Serial.available()>0)
{
motor.writeMicroseconds(2000);
delay(1);
motor.writeMicroseconds(2000);
}
}
5.5.3 : BRUSHLESS VS BRUSHED MOTORS
Limitations of brushed DC motors overcome by BLDC motors include lower efficiency and susceptibility of the commutator assembly to mechanical wear and consequent need for servicing, at the cost of potentially less rugged and more complex and expensive control electronics. A BLDC motor has permanent magnets which rotate and a fixed armature, eliminating the problems of connecting current to the moving armature. An electronic controller replaces the brush/commutator assembly of the brushed DC motor, which continually switches the phase to the windings to keep the motor turning. The controller performs similar timed power distribution by using a solid-state circuit rather than the brush/commutator system.
BLDC motors offer several advantages over brushed DC motors, including more torque per weight and efficiency, reliability, reduced noise, longer lifetime (no brush and commutator erosion), elimination of ionizing sparks from the commutator, more power, and overall reduction of electromagnetic interference (EMI). With no windings on the rotor, they are not subjected to centrifugal forces, and because the windings are supported by the housing, they can be cooled by conduction, requiring no airflow inside the motor for cooling. This in turn means that the motor’s internals can be entirely enclosed and protected from dirt or other foreign matter.
The maximum power that can be applied to a BLDC motor is exceptionally high, limited almost exclusively by heat, which can weaken the magnets. A BLDC motor’s main disadvantage is higher cost, which arises from two issues. First, BLDC motors require complex electronic speed controllers to run. Brushed DC motors can be regulated by a comparatively simple controller, such as a rheostat (variable resistor). However, this reduces efficiency because power is wasted in the rheostat. Second, some practical uses have not been well developed in the commercial sector. For example, in the Radio Control (RC) hobby, even commercial brushless motors are often hand-wound while brushed motors use armature coils which can be inexpensively machine-wound.
BLDC motors are often more efficient at converting electricity into mechanical power than brushed DC motors. This improvement is largely due to the absence of electrical and friction losses due to brushes. The enhanced efficiency is greatest in the no-load and low-load region of the motor’s performance curve. Under high mechanical loads, BLDC motors and high-quality brushed motors are comparable in efficiency.
5.6 : ELECTRONIC SPEED CONTROLLER
The purpose of a motor speed controller is to take a signal representing the demanded speed, and to drive a motor at that speed. With the purpose to vary an electric motor’s speed and direction ESCs are often used on electrically-powered radio controlled models. An ESC can be a stand-alone unit which plugs into the receiver’s throttle control channel or incorporated into the receiver itself, as is the case in most toy-grade R/C vehicles. Some R/C manufacturers that install proprietary hobby-grade electronics in their entry-level vehicles, vessels or aircraft use onboard electronics that combine the two on a single circuit board.
Figure.28 Electronic Speed Control
5.6.1 : FUNCTION
Regardless of the type used, an ESC interprets control information not as mechanical motion as would be the case of a servo, but rather in a way that varies the switching rate of a network of field effect transistors, or FETs. It also allows much smoother and more precise variation of motor speed in a far more efficient manner than the mechanical type with a resistive coil and moving arm once in common used. Most modern ESCs incorporate a battery eliminator circuit (or BEC) to regulate voltage for the receiver, removing the need for receiver batteries. BECs are usually either linear or switched mode voltage regulators.
DC ESCs in the broader sense are PWM controllers for electric motors. The ESC generally accepts a nominal 50 Hz PWM servo input signal whose pulse width varies from 1 ms to 2 ms. When supplied with a 1 ms width pulse at 50 Hz, the ESC responds by turning off the DC motor attached to its output. A 1.5 ms pulse-width input signal results in a 50% duty cycle output signal that drives the motor at approximately half-speed. When presented with 2.0 ms input signal, the motor runs at full speed due to the 100% duty cycle (on constantly) output.
5.6.2 :HOW IS SPEED VARIES?
When we watch a film in the cinema, or the television, what we are actually seeing is a series of fixed pictures, which change rapidly enough that our eyes just see the average effect ‘ movement. Now by switching the motor’s supply on and off very quickly. If the switching is fast enough, the motor doesn’t notice it, it only notices the average effect. As the amount of time that the voltage is on increases compared with the amount of time that it is off, the average speed of the motor increases this on-off switching is performed by power MOSFETs. A MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor).It is a device that can turn very large currents on and off under the control of a low signal level voltage.
If the supply voltage is switched fast enough, it won’t have time to change speed much, and the speed will be quite steady. This is the principle of switch mode speed control. Thus the speed is set by PWM ‘ Pulse Width Modulation. The graph below shows the speed of a motor that is being turned on and off fairly slowly:
Each switching on and off of the speed controller MOSFETs results in a little power loss. Therefore the greater the time spent switching compared with the static on and off times, the greater will be the resulting ‘switching losses in the MOSFETs. The higher the switching frequency, the more stable is the current waveform in the motors. The connection below shows the motor, esc and the battery.
Figure.29 Speed of motor that is being turned on and off allowably
5.7: CAMERAS
Specifications:-
‘ VGA Camera
‘ Transmitting range ‘ 20 to 25 meters
‘ Transmitter voltage ‘ 9 to 12 DC
‘ Receiving voltage ‘ 9 to 12 DC
‘ Resolution ‘ 640*480
Figure. 30 VGA Camera
A visual graphics array is a camera that has a resolution of 480 pixels high by 640 pixels wide. It is a digital camera identified by the rating of the megapixel that shows the highest resolution of the camera. It was developed by IBM in the year 1987.
VGA was originally developed by in 1987 by IBM as a means for their PS/2 personal computers to display higher-resolution graphics on a monitor. It was replaced in the early 1990s by the super video graphics array standard. Although VGA is no longer used for standard PC displays, it is still used today in some mobile and handheld electronics.
5.8: LITHIUM POLYMER BATTERY
Application of LIPO battery:-
A compelling advantage of Li-poly cells is that manufacturers can shape the battery almost however they please, which can be important to mobile phone manufacturers constantly working on smaller, thinner, and lighter phones.
Li-poly batteries are also gaining favour in the world of radio-controlled aircraft as well as radio-controlled cars, where the advantages of both lower weight and greatly increased run times can be sufficient justification for the price. Some air soft gun owners have switched to LiPo batteries due to the above reasons and the increased rate of fire they provide. However, lithium polymer-specific chargers are required to avoid fire and explosion. Explosions can also occur if the battery is short-circuited, as tremendous current passes through the cell in an instant. Radio-control enthusiasts take special precautions to ensure their battery leads are properly connected and insulated. Furthermore fires can occur if the cell or pack is punctured. Radio-controlled car batteries are often protected by durable plastic cases to prevent puncture. Specially designed electronic motor speed controls are used to prevent excessive discharge and subsequent battery damage. This is achieved using a low voltage cut-off (LVC) setting that is adjusted to maintain cell voltage greater than (typically) 3 V per cell.
Li-poly batteries are also gaining ground in PDAs and laptop computers, such as Apple’s Mac Book family, Amazon’s Kindle, Lenovo’s Think pad X300 and Ultra bay Batteries, the OQO series of palmtops, the HP Mini and Dell products featuring D-bay batteries. They can be found in small digital music devices such as iPods, Zunes, and other MP3 players and the Apple iPhone and iPad, as well as gaming equipment like Sony’s PlayStation 3 wireless controllers. They are desirable in applications where small form factors and energy density outweigh cost considerations.
Storage:-
Unlike certain other types of batteries, lithium polymer batteries can be stored for one or two months without significantly losing charge. However, if storing for long periods, manufacturers recommend discharging the battery to 40% of full charge. In addition, other sources recommend refrigerating (but not freezing) the cell.
Lithium polymer charger:-
LiPoly batteries must be charged carefully. The basic process is to charge at constant current until each cell reaches 4.2 V; the charger must then gradually reduce the charge current while holding the cell voltage at 4.2 V until the charge current has dropped to a small percentage of the initial charge rate, at which point the battery is considered 100% charged. Some manufacturers specify 2%, others 3%, but other values are also possible. The difference in achieved capacity is minute.
Lipo battery used:-
Figure.31 LIPO battery
Figure.32 LIPO battery
Battery specification:-
TABLE.2 LIPO BATTERY SPECIFICATION
Capacity(mAh) 1300
Config(s) 3
Discharge(c) 20
Weight(g) 104
Max charge rate(c) 2
Length-A(mm) 76
Height-B(mm) 33
Width-C(mm) 21
Cells 3
Voltage 11.1
Peak discharge(10 sec) 30C
5.8.1 : LIPO BATTERY CHARGER USED
Lipo charger is used for charging the 1 to 6 cells lipo battery with a dedicated slot for each type. The display shows the amount of charge left in the battery and allows selecting the current required to charge the battery. The maximum current depends on the power source used, which may vary from 0.1A to 5A.
Figure.33 Lipo battery charger
There are two sets of wires provided with the charger. The battery can be charged in 3 modes that are,
‘ Normal mode ‘ in this mode the battery charging occurs using the specified current at a moderate rate. It maintains the partial balance.
‘ Fast ‘ mode here the battery is charged at a faster rate.
‘ Balanced mode ‘ maintains a perfect balance between all the three cells being charged.
5.8.2 : FEATURES
‘ Microprocessor controlled
‘ Delta – peak sensitivity
‘ Individual cell balancing
‘ Li ‘ ion, Lipo and Life capable
‘ Ni ‘ Cd and NiMH capable
‘ Large range of charge currents
‘ Store function, allows safe storage current
‘ Time limit function
‘ Input voltage monitoring. (Protects car batteries at the field)
‘ Data storage (store up to 5 packs in memory)
Specifications:-
‘ Input voltage: 11~18V
‘ Circuit power: max charge: 50W / max discharge: 5W
‘ Charge current range: .1~5.0A
‘ Discharge current range: .1~1.0A
‘ Ni ‘ MH/NiCD cells: 1~15
‘ Li ‘ ion/Poly cells: 1~6
‘ Pb battery voltage: 2~20v
‘ Weight: 277g
‘ Dimensions: 133x87x33mm
Chapter 6 : SCOPE FOR FUTURE ENHANCEMENT
Future of a quad-copter is quite vast based on various application fields it can be applied to. Quad-copter can be used for conducting rescue operations where it’s humanly impossible to reach. In terms of its military applications it can be more widely used for surveillance purposes, without risking a human life. As more automated quad-copters are being developed, there range of applications increases and hence we can ensure there commercialization. Thus quad-copter can be used in day to day working of a human life, ensuring their well-being.
In future the GPS system and be added to automated quad-copters ,which can travel on defind path and after reach to the Destination it automatically return and come to the source.
With further study and advancement in technology, designers are quite sure that a quad-copter can be used for construction of huge towers and buildings. The main advantage in the future use of a quad-copter for various purposes is that risk to human life, may it be because of war or due to commercial accidents can be greatly avoided. The future of quad-copter sure is bright and not far ahead.
Chapter 7 : CONCLUSION
As per the design specifications, the quad copter self stabilizes using the array of sensors integrated on it. It attains an appropriate lift and provides surveillance of the terrain through the camera mounted on it. It acts appropriately to the user specified commands given via a remote controller.
Its purpose is to provide real time video streaming from areas which are physically in-accessible by humans.
Thus, its functionality is monitored under human supervision, henceforth being beneficial towards military applications. It is easy to maneuver, thereby providing flexibility in its movement. It can be used to provide surveillance at night through the usage of infrared cameras but in our case it is not possible as we have used VGA camera. The system can further be enhanced for future prospects.
Chapter 8 : ANNEXURE
Chapter 9: REFERENCES
a. ‘Unmanned Aerial vehicle’ , Sung Ho Rhee and Yong Seung Lee (Application no. :12/954,975)
b. ‘Flying toy’ , Alexander Jozef Magdalena van de Rostyne and Kwok Leung Wong (Application no. 12/696,183)
c.’Aerial Photography camera system for a helicopter’ , KIM,jae and Dong(Application no.PCT/KR99/00479)
d. ‘Controlling movement of an unmanned vehicle’ , markus kemper (Application no. 11/704,030)
e. ‘Unmanned flying vehicle made with PCB’ , Sungho rhee and Yong seunglee (Application no. 12/954,975)
f. ‘Controlling movement of unmanned vehicle’ , Adam s. Ehrmantrut (Application no. 11/704,030)
g. ‘An unmanned aerial helicopter’ , CHAAN and Keem Ian (PCT/SOT 2012/000336)
e. ‘Flying roller hemming anvil process’ , James B. Toeniskoetter (Application no. 12/221,765)
f. ‘Remotely controlled flying platform , Paul s. Moller (Application no. 15,100)
g. ‘Flapping flying robot’ , Masaki Fuchiwaki,Tadatsugu Imura and Kazuhiro Tanaka (Application no. 13/384,424)
h. ‘toy airship alternately configurable as a hydrofoil craft , Keith A. Hippely and Randolph Cyr (Application no. 19/497,441)
i. ‘airborne cleaning and painting robot’ , Gino Francis Ngugang (Application no. 09/684,382)
j. ‘Aerial robot’ , Samuel A. Johnson (Application no. 11/361,122)
k. ‘Aerial robot with dispensable conductive filament’ Samuel Alan Jhonson,Willian Dennis Burkard,Robert H. Mimlitch and Henry Mimlitch (Application no. 11/737,591)
l. ‘flying apparatus’ , Phillip matthew Jermyn (Application no. 12/475,048)
FIGURES:
Figure 1 to 9- source: www.instructtables.com
Figure 10- source: www.challenge.toradex.com
Figure 13- source: www.allaboutquadcopters.blogspot.com
Figure 14- source: www.people.ece.cornell.edu
Figure 15,17,18- source: www.cheers4all.com
Figure 16- source: www.altera.com & www.dprg.org
Figure 20- source: www.en.wikipedia.org
Figure 21- source: www.quadcopters.co.uk
Figure 22- source: www.chigift.en.alibaba.com
Figure 23- source: www.smaccmpilot.org
Figure 24- source: www.aliexpress.org
Figure 25- source: www.sensorsmag.com
Figure 26- source: www.cvel.clemson.edu
Figure 29- source: www.homepages.which
Figure 30- source: www.alibaba.com
Figure 31- source: www.quadcopters.co.uk
Figure 33- source: www.quadcopters.co.uk
Chapter 10: APPENDIX
Appendix A:
1. UAV (Unmanned Ariel Vehicle)
2. UAS (Unmanned Ariel System)
3. DIY (Do It Yourself)
4. TTL (Transistor ‘ Transistor ‘ Level)
5. ESC (Electronic Speed Controller)
6. Lipo (Lithium ion Polymer)
Appendix :B
Object No. of object Cost (of single object)
BLDC motors 4 1000
Matching ESC 4 900
Propellers 4 80
Arduino board 1 2000
Arms 4 15
Battery 1 1400
Battery charger 1 1000
Wires 1 (25pcs) 130
Usb cable 1 70
camera 1 2000
Footaba 1 16500
Wireless receiver 1 3700
Total Rs. 34780