Wednesday 30 October 2013

Advancements and innovations in Multirotors

AWESOMENESS OF TECHNOLOGY


Researchers develop 3D-printed

Drones capable of self assembly



Distributed Flight Array

The Distributed Flight Array (DFA) has been developed by a team of researchers at the Institute for Dynamic Systems and Control (IDSC) at ETH Zürich university in Switzerland.
Each robot has a 3D-printed hexagonal plastic chassis with magnets fixed to the sides of the frame and a single propeller fitted in the middle.
Independently, the honeycomb-shaped robots fly in an erratic and uncontrolled way. However, the robots are able to detect each other, link to form a bigger craft and then fly in a controlled manner as a single unit. The task of keeping the multi-propeller system in flight is distributed across the network of vehicles.
Each independent module exchanges information with the others and uses sensors to determine how much thrust it needs for the array to take off and maintain flight.
"The Distributed Flight Array is a flying platform consisting of multiple autonomous single propeller vehicles that are able to drive, dock with their peers and fly in a coordinated fashion," explains the IDSC. "Once in flight the array hovers for a few minutes, then falls back to the ground, only to repeat the cycle again."



Distributed Flight Array



"If the array's levelled flight is disturbed, each vehicle individually determines the amount of thrust required to correct for the disturbance based on its position in the array and the array's motion," IDSC said.
The project has been developed for two reasons, Maximilian Kriegleder from the IDSC told Dezeen: as a research platform for distributed control and estimation, and as an artistic installation that could illustrate such control of robots to members of the public.


Although the project was not designed for a specific purpose, Kriegleder suggests that the technology could be used for transportation systems. "The developed algorithms apply to any real systems that needs to be scalable and distributed," Kriegleder told Dezeen. "One specific example could be a scalable mass transportation system, where one only adds so many modules that a certain payload could be lifted."
The DFA project was launched in 2008 as a postgraduate class at ETH Zürich university and is being continued by Dr. Raymond Oung as his PhD project.

The World's First Solar-Powered Helicopter Takes Flight

All right, it’s just a remote-controlled helicopter. But the SolarCopter is still driving new technology that could add solar power to copters both large and small.

Following projects like the Solar Impulse and NASA’s Helios wing, the idea of propelling aircraft using solar energy isn’t as fanciful as it used to be, even if it’s still experimental and full of practical holes. Before long, we’ll surely see solar power used to aid traditional airplanes, even if it’s not used as the main fuel.
To show what’s possible, a team of masters students from the U.K. have built what they call the world’s first "solar copter"--a quadrotor that flies solely on solar power. At the moment, it is capable only of short flights. But the team say it should fly longer soon, once they’ve added a storage system.


"The SolarCopter is a quadrotor design that incorporates a solar panel providing the power for the propulsion system," the six students say in a joint email. "It is controlled in the same way as a standard battery-powered quadrotor. Optimum thrust-to-weight ratio was mainly achieved through an efficient propulsion system, unique frame design, and an optimized solar panel."

Future versions could be used for surveillance, search, and rescue, and tracking animal migrations, perhaps in Africa, Australia, Middle East, and Southern Europe, where there is more sun than in England. Its technology could also help increase the range of conventional choppers, and perhaps give other solar aircraft, such as the Impulse, better maneuverability and control. (At the moment, for all its elegance, the Impulse is quite likely to be blown off course).


At Queen Mary, University of London, Jibran Ahmed, Shakir Ahmed, Irmantas Burba, Pourshid Jan Fani, George Kowfie, and Kazimierz Wojewoda hope to keep working on the concept as they finish their studies. "When the realization came that there were no solar-powered helicopters in existence, it seemed like a great engineering challenge to take on," they say. "The team is of multidisciplinary students that are driven by the urge to do something different in the aviation industry."

FESTO BIONICOPTER THE ROBOTIC DRAGONFLY SCIENCE FICTION PREDICTED


It’s always fascinating when reality catches up to science fiction, and with the current advances in quadcopters and robotics, it seems like that is happening on a daily basis. Today’s mind-blowing robotics demonstration is brought to you by Festo, which has made a quadcopter that looks and moves just like a dragonfly.
You see it all the time in shows and comic books where science fiction and fantasy cross paths. Robotic insects that can be controlled by the protagonist and exist to act as invisible eyes and ears, and maybe even sneak into somewhere small and save the day. It’s an incredibly cool idea, but as we’ve only barely mastered tiny flying machines that look like an actual machine, tiny machines that look like dragonflies are still far off. That’s still true, but now it’s only mostly true. The Festo BionicOpter was built to fly in very much the same way as a dragonfly, giving it some unique flyin. 


The way a dragonfly maneuvers in the air is fairly unique compared to the other flying creatures in the world. Their design is such that they can glide without moving their wings, hover in place, or move quickly in any direction. Their four wings are positioned in two different positions, and they move in slightly different ways, which is what sets this insect apart from the rest of the fliers out there. Replicating this ability in a flying machine requires not only a unique physical design, but a unique program to drive the machine. Despite being a little different from the other quadcopter machines out there, the BionicOpter can still be easily driven with a smartphone app.g abilities.


The BionicOpter isn’t commercially available at this time, but the arm-sized dragonfly serves as a perfect example of how far we’ve come in such a short time with robotics. To be able to emulate the flying mechanisms of a creature found in nature is one of the most complicated things you can do with robotics, especially something as small and unique as a dragonfly. It’s only a matter of time before they shrink this technology down to the size of actual dragonflies, and that’s when the fun starts.

Mind-controlled quadcopter takes to the air – promising advances for prosthetics





How close are we getting to actual brain control? It’s starting to seem not far off at all. On the more silly end of the spectrum, we’ve seen robotic ears and tails that respond to brainwaves; but we’ve also seen more recently a Chilean company that has created abrain interface for designing printable objects, a mind-controlled exoskeleton for helping people walk, even mind-to-mind communication.
A team of researchers at the University of Minnesota has just added another exciting new technology to the list: a quadcopter that can perform feats of aerial agility, controlled entirely by the pilot’s thoughts.


Using electroencephalography (EEG), a non-invasive cap fitted with 64 electrodes reads the electrical impulses of the brain to control the copter. Thinking of making a fist with the left hand, for example, fires off certain neurons in the brain’s motor cortex; the cap interprets this pattern and sends a command to the copter to turn left. Other commands include thinking of making a fist with the right hand to turn right, and making two fists to tell the copter to rise.
In this way, five subjects — two male and three female — were able to successfully pilot the quadcopter quickly and accurately for a sustained period of time through an obstacle course in the university’s gymnasium.
Professor Bin He, lead author of the study “Quadcopter control in three-dimensional space using a non-invasive motor imagery-based brain-computer interface“, hopes that the research will be developed to create solutions for the disabled. “Our next goal is to control robotic arms using non-invasive brain wave signals, with the eventual goal of developing brain-computer interfaces that aid patients with disabilities or neurodegenerative disorders,” he said.
This will not be the first mind-controlled robotic arm; however, the robotic arm announced in December last year requires a brain implant. His solution is much less invasive, requiring no surgery to implant the interface.

The future: Quadcopter UAVs recharging your smartphone with wireless power


The University of Nebraska’s NIMBUS Lab has developed unmanned quadcopters that can fly around and wirelessly transmit power to devices. Ostensibly these UAVs have the rather unromantic purpose of recharging remote sensors — weather stations, highway monitoring/messaging systems, and other similar, unattended electronic devices — but it also means that, in the future, you might be able to call out a quadcopter to recharge your mobile phone.
Wireless power, delivered by UAV
The quadcopters (their creators, Brent Griffin and Carrick Detweiler, call them quadrotors) use strongly coupled magnetic resonance to provide wireless power. The process of transferring energy is very easy — you have two coils of wire that are tuned to resonate at the same frequency, one on the quadcopter and one on the receiving device (pictured below). By running an oscillating current through one of the coils, an oscillating magnetic field is produced — which is picked up by the receiving coil, effectively transferring power.
Strongly coupled magnetic resonance power transfer
At 20cm (8in) — the optimum distance is defined by the wavelength of the oscillating power — the quadcopter system can transmit 5.5 watts with an efficiency of 35%. This is more efficient than non-resonant inductive coupling (and works over a larger distance), and as an added bonus, magnetic resonance deals well with occlusions and other atmospheric interference (something that laser power transmission cannot surmount). The one problem with strongly coupled magnetic resonance, though — as you can see in the video below — is that the quadcopter needs to be almost perpendicular with the receiving device for power to be transmitted. According to IEEE Spectrum, the NIMBUS Lab team is currently working on ways of autonomously keeping the UAV exactly 20cm directly above the receiving device.
Ultimately, these UAVs will be fully autonomous, constantly whizzing around recharging any and all battery-powered devices, and then returning to base to refuel. A few years from now, AT&T (or Apple) could maintain a fleet of mobile, UAV power stations that automatically recharge any iPhone or iPad that runs low on power. Many medical, implantable devices, such as pacemakers, are currently recharged using magnetic resonance — a trend that will only continue with the advent of truly wearable computers that are implanted beneath your skin. In the future, when most of our organs areaugmented with computer tech, we might rely on these UAVs to quite literally keep our batteries topped up while we’re out and about.

SWARM TELEOPERATION – ENHANCING THE COMMUNICATION IN FLYING ROBOT SYSTEMS


With the help of computer simulations and prototypes Max Planck researchers are trying to enhance the communication in human and multi-robot interactions.


Wouldn’t it be nice if each household had an electronic helper or if robots could fulfill the tasks  that are too dangerous or troublesome for humans? Things that are taken for granted in movies such as the "Bicentennial Man" or "I-Robot" are still very futuristic scenarios in reality. Paolo Robuffo Giordano investigates the fundamental aspects necessary for the relevant technical development at the Max Planck Institute for Biological Cybernetics in Tübingen, Germany. He and his team mainly work with flying multi-robot systems, which receive instructions from a human user and are then able to fulfill the details of the task autonomously.


Paolo Robuffo Giordano is the project leader of the Human Robot Interaction Group in the Department Human Perception, Cognition and Action of Heinrich Bülthoff at the MPI for Biological Cybernetics. His team works with quadrocopters, small flying robots generally referred to as" unmanned aerial vehicles" (UAVs) by scientists.   Navigated by a human operator, four or more of these UAVs, which are approximately 16 inches in diameter, perform local tasks maintaining a programmed, spatial configuration.   

If the UAVs are instructed to fly forward in a programmed formation, they do so while avoiding obstacles autonomously. While flying, the robots provide the human operator with sensory feedback - visual, proprioceptive, tactile and auditory, depending on the equipment and programming, which maximizes the operator’s awareness. If an object is in the way, the control will be aggravated in that specific direction until the robots have overcome the obstacle. "It's like actually flying against a wall”, Robuffo Giordano explains. The robots autonomously keep track of each other using cameras and regulate their position to one another. The human operator can track the UAVs on his monitor." We are investigating some fundamental aspects of these topics, which are necessary for any possible future applications," the scientist explains." The development and programming of such robots is mainly an application of mathematical theories. That's why we see ourselves as engineers."   


The researchers are also further investigating the interactions between remote multiple robots in multi-robot systems and a human operator in order to enhance communication. Some aspects of such multi-robot systems mimic the movement of swarms of birds. This scenario becomes important when modeling big formations in computer simulations, in which the robots do not keep a defined distance to one another, but always need to keep in sight of another robot within the formation.   The results of the fundamental research done by Robuffo Giordano’s team can be applied in various sectors. It is possible, for example, to attach a hand to one or more of the quadcopters and through this to interact with and grasp objects as if the operator’s hands have an unlimited range. Likewise, robots can be equipped with various sensors to collect different environmental data. They can convey the information to a computer or a human operator." These robots might be an extension of our own senses," says Paolo Robuffo Giordano.. Using this approach, unknown or potentially dangerous areas can be explored without endangering any humans. Still in the field of the imagination lie applications in the medical field, where doctors deploy teams of nano robots inside the human body to examine and treat at exact locations.

Quadrotor drone directs swarm robots


A group of researchers from the Universite Libre de Bruxelles and Instituto Universitario de Lisboa have demonstrated a way for different robots to communicate with one another in real time in order to overcome obstacles and complete tasks.



A group of self-assembling swarm bots work well together when assigned particular tasks. The problem, however, is that each one has a limited perspective of its surroundings; that is, the bots can only see so far, and as a result, are not privy to obstacles that might lie ahead.
To overcome this limitation, researchers introduced an overhead quadrotor drone. Its purpose is to provide the ground bots with a broader understanding of the area surrounding them, so that they can overcome obstacles and more efficiently complete their tasks.

The overhead quadrotor uses stereo imagery to compute the area around the swarm bots. This gives it the ability to determine obstacles such as, say, a hill or bridge, and ways in which they can be overcome.
The aerial bot takes this information, runs an onboard simulation to see how many swarmbots will have to team up to get past the obstacle, and then sends out an order for the ground bots to execute.




The whole concept is referred to as Swarmanoid, and it refers to how the team is using different bots with different capabilities, and combining them to overcome obstacles as a means for more efficiently completing tasks.
This is, in particular, a big step in regards to communication technology. There is no need for GPS, IMU, hardware IDs, etc. in this system: The group was able to get it down to a point where the flying robot is able to use visual feedback from the flying robot via LED, cameras, and a little dash of intelligence in the robots to take the information being communicated and make the adjustments necessary.


Drone driver licenses? How to make flying
 robots safe for  skies !!


A romantic pre-wedding photo shoot turned sour when the photographer's camera-equipped quadcopter swerved out of control and hit the groom on the head. 
"We cleaned up the blood and just kept going," Davey Orgill, the photographer — who had been filming the bride- and groom-to-be on Aug. 1 on a grassy field near La Barge, Wyo. — told NBC News. After the wedding, with the couple's permission, he uploaded the fateful shot to YouTube where it's been viewed more than 1 million times.


(10/11/2013) Julian Szajdzicki catches an AR Parrot 2.0 drone during a demonstration by Nodecopter at the DARC conference's AfterDARC session in NYU's...
Julian Szajdzicki catches an AR Parrot 2.0 drone during a demonstration by Nodecopter at the AfterDARC session.
Hobbyist drone pilots will tell you that small drones are notoriously temperamental and accident-prone. Community discussion forums are filled with crash-related queries, and YouTube documents ample evidence of camera-carrying quadcopters or hexacopters getting tangled up in trees and toppling to the ground. 
"In the late 1920s, aircrafts were still failing out of the sky left and right," Missy Cummings, who studies drones and autonomous systems at MIT, said at a panel discussion at the Drones and Aerial Robotics Conference (DARC) in New York on Saturday. Today, drone technology is at the same place.
Before company-operated drones are integrated into U.S. airspace in 2015, as the Federal Aviation Administration's Modernization and Reform Act of 2012 mandates, safety regulation is one of hurdles the FAA will need to clear. A panel of experts at DARC agreed that before drones become a daily sighting, technology and humans both need to start behaving just a little bit better. 

Small drones like quadcopters can be bought online, and adding warnings to the bots could be an easy first step. "The DJI Phantom doesn't come with a label saying, 'Hey, this could hurt someone,'" Mike Winn, a founder of DroneDeploy, a company that is building autonomous control platforms, said. "It's like buying a model race car." In other words, there's no lengthy list of all the damage it can do.
One way to assure a minimum level of competence could be pre-use certification, a "driver license" of sorts for pilots who fly the birds. 
Operators of small military drones like Ravens are trained before they can use them, and Capt. Adam Gorrell — who trained drone pilots and flew them himself in the U.S. Air Force, before becoming a professor at the Air Force Academy — sees a similar training system working for domestic operators, too. A different, smaller craft perhaps wouldn't need the same amount of training time, but the "mark in the sand" for flight readiness could shifted accordingly, he said.
The Northeast UAS Airspace Integration Research Alliance (NUAIR), a New York and Massachusetts coalition applying to be a drone test site that will help the FAA form its safety regulations, is considering including pre-flight training for emergency responders at its base in Syracuse, N.Y. This could equip firefighters and police to deploy the crafts safely and quickly, Andrea Bianchi, a representative of the NUAIR said. 

Skyfall quadcopter by MIT students

Classifying the crafts by weight could help regulators come up with an effective safety strategy, several panelists agreed. 
Small drones range from a few grams in weight to several pounds. Just as driver licenses are distinguished by vehicle class — trucks or or limos or motorbikes or cars — it makes sense to separate the qualifications for drone users, too. The safety risk they pose differs depending on their size, Winn, of DroneDeploy, pointed out. "You can't lump everything together."
Others are less sure that humans, even trained ones, can be trusted at all. Drones would need to come with software-based "training wheels," or "safety bumpers," to protect amateurs and reckless pilots from harming themselves and others, Cummings said.
Just like cars are getting lane departure warnings, proximity sensors and adaptive cruise control, drones will eventually get detect-and-avoid technologies, which will give them the smarts to dodge a bird or another craft in its path. The commercial applications aren't quite ready, but mapping and sensing technologies for small drones is progressing quite briskly in research labs.
"In the end the technology will have to rise to the level of smartness to stop humans from doing stupid things like taking their own heads off," Cummings observed, adding that for as long as we have been printing them, people have been tossing out instruction manuals unread. 
What about drone drunk driving?


"I want to show just how safely can you control a drone, at what level of blood alcohol," Cummings said. "If I ever get the funding." 

And many advancements still to go !!!!!!





Saturday 26 October 2013

Building a Quadcopter

                           BUILDING A QUADCOPTER


SO .... WHAT IS A QUADCOPTER ??

  
QuadCopter is a helicopter with four rotors, so it’s also known as quadrotor. Because of its unique design comparing to traditional helicopters, it allows a more stable platform, making quadcopters ideal for tasks such as surveillance and aerial photography. And it is also getting very popular in UAV research in recent years.
The Quadcopters exist in many different sizes. From as small as a CD up to something as big as one meter in width.

       


On a regular helicopter has one big rotor to provide all the lifting power and a little tail rotor to offset the aerodynamic torque generated by the big rotor (without it, the helicopter would spin almost as fast as the propeller)
Unlike a helicopter, a quadrotor has four rotors all work together to produce upward thrust and each rotor lifts only 1/4 of the weight, so we can use less powerful and therefore cheaper motors. The quadcopter’s movement is controlled by varying the relative thrusts of each rotor.
These rotors are aligned in a square, two on opposite sides of the square rotate in clockwise direction and the other two rotate in the opposite direction. If all rotors turn in the same direction, the craft would spin would spin just like the regular helicopter without tail rotor. (if you are not sure what I mean, check out this video) Yaw is induced by unbalanced aerodynamic torques. The aerodynamic torque of the first rotors pair cancelled out with the torque created by the second pair which rotates in the opposite direction, so if all four rotors apply equal thrust the quadcopter will stay in the same direction.





To maintain balance the quadcopter must be continuously taking measurements from the sensors, and making adjustments to the speed of each rotor to keep the body level. Usually these adjustments are done autonomously by a sophisticated control system on the quadcopter in order to stay perfectly balanced. A quadcopter has four controllable degrees of freedom:Yaw, Roll, Pitch, and Altitude. Each degree of freedom can be controlled by adjusting the thrusts of each rotor.





DEGREES OF FREEDOM !

Yaw (turning left and right) is controlled by turning up the speed of the regular rotating motors and taking away power from the counter rotating; by taking away the same amount that you put in on the regular rotors produces no extra lift (it won’t go higher) but since the counter torque is now less, the quadrotor rotates as explained earlier.3.- control becomes a matter of which motor gets more power and which one gets less.

Roll (tilting left and right) is controlled by increasing speed on one motor and lowering on the opposite one.

Pitch (moving up and down, similar to nodding) is controlled the same way as roll, but using the second set of motors. This may be kinda confusing, but roll and pitch are determined from where the “front” of the thing is, and in a quadrotor they are basically interchangeable; but do take note that you have to decide which way is front and be consistent or your control may go out of control.


quadcopter-rotatingquadcopter-foward

This illustrates how the adjustments made for each degree of freedom must work together to achieve a desired motion. Now, building and flying a quadrotor from a remote control is simple and fun and stuff, but people noting the inherently stable flight (in theory with equal speed of the motors the thing keeps itself level) and ease of control (only three functions and they are all basically take speed from one and put in the other), people love to make them autonomous (flies itself) and semi-autonomous.

COMPONENTS OF QUAD :

Frame

Frame is the structure that holds all the components together. The Frame should be rigid, and be able to minimize the vibrations coming from the motors. 
A QuadCopter frame consists of two to three parts which don’t necessarily have to be of the same material:
  • The center plate where the electronics are mounted
  • Four arms mounted to the center plate
  • Four motor brackets connecting the motors to the end of the arms
Most available materials for the frame are:
  • Carbon Fiber
  • Aluminium
  • Wood, such as Plywood or MDF (Medium-density fibreboard)




Brushless Motors

A little background of Brushless motor. They are a bit similar to normal DC motors in the way that coils and magnets are used to drive the shaft. Though the brushless motors do not have a brush on the shaft which takes care of switching the power direction in the coils, and this is why they are called brushless. Instead the brushless motors have three coils on the inner (center) of the motor, which is fixed to the mounting.


Generally brushless motors spin in much higher speed and use less power at the same speed than DC motors. Also brushless motors don’t lose power in the brush-transition like the DC motors do, so it’s more energy efficient.
Brushless motors come in many different varieties, where the size and the current consumption differ. When selecting your brushless motor you should take care of the weight, the size, which kind of propeller you are going to use, so everything matches up with the current consumption. When looking for the brushless motors you should notice the specifications, especially the “Kv-rating“.
The Kv-rating indicates how many RPMs (Revolutions per minute) the motor will do if provided with x-number of volts. The RPMs can be calculated in this way: RPM=Kv*U An easy way to calculate rating of motor you need, check out the online calculator eCalc. It’s an amazing tool that helps you decide what components to purchase depending on the payload that you want to carry.

propellers

On each of the brushless motors there are mounted a propeller.
You might not have noticed this on the pictures, but the 4 propellers are actually not identical. You will see that the front and the back propellers are tilted to the right, while the left and right propellers are tilted to the left.
Like I mentioned before, 2 rotors rotates in the opposite directions to the other two to avoid body spinning. By making the propeller pairs spin in each direction, but also having opposite tilting, all of them will provide lifting thrust without spinning in the same direction. This makes it possible for the QuadCopter to stabilize the yaw rotation, which is the rotation around itself.


The propellers come in different diameters and pitches (tilting). You would have to decide which one to use according to your frame size, and when that decision is made you should chose your motors according to that. Some of the standard propeller sizes used for QuadCopters are:
  • EPP1045 10 diameter and 4.5 pitch  this is the most popular one, good for mid-sized quads
  • APC 1047 10 diameter and 4.7 pitch  much similar to the one above
  • EPP0845  8 diameter and 4.5 pitch  regularly used in smaller quads
  • EPP1245  12 diameter and 4.5 pitch  used for larger quads which requires lot of thrust
  • EPP0938  9 diameter and 3.8 pitch  used in smaller quads.

But in general when selecting propellers you can always follow these rules:
  1. The larger diameter and pitch the more thrust the propeller can generate. It also requires more power to drive it, but it will be able to lift more weight.
  2. When using high RPM (Revolutions per minute) motors you should go for the smaller or mid-sized propellers. When using low RPM motors you should go for the larger propellers as you can run into troubles with the small ones not being able to lift the quad at low speed.

ESC – Electronic Speed Controller

The brushless motors are multi-phased, normally 3 phases, so direct supply of DC power will not turn the motors on. Thats where the Electronic Speed Controllers (ESC) comes into play. The ESC generating three high frequency signals with different but controllable phases continually to keep the motor turning. The ESC is also able to source a lot of current as the motors can draw a lot of power.


The ESC is an inexpensive motor controller board that has a battery input and a three phase output for the motor. Each ESC is controlled independently by a PPM signal (similar to PWM). The frequency of the signals also vary a lot, but for a Quadcopter it is recommended the controller should support high enough frequency signal, so the motor speeds can be adjusted quick enough for optimal stability (i.e. at least 200 Hz or even better 300 Hz PPM signal). ESC can also be controlled through I2C but these controllers are much more expensive.
When selecting a suitable ESC, the most important factor is the source current. You should always choose an ESC with at least 10 A or more in sourcing current as what your motor will require. Second most important factor is the programming facilities, which means in some ESC you are allowed to use different signals frequency range other than only between 1 ms to 2 ms range, but you could change it to whatever you need. This is especially useful for custom controller board.

Battery

As for the power source of the quadcopter, I would recommend LiPo Battery because firstly it is light, and secondly its current ratings meet our requirement. NiMH is also possible. They are cheaper, but it’s also a lot heavier than LiPo Battery.


Battery Voltage

LiPo battery can be found in a single cell (3.7V) to in a pack of over 10 cells connected in series (37V). A popular choice of battery for a QuadCopter is the 3SP1 batteries which means three cells connected in series as one parallel, which should give us 11.1V.

Battery Capacity

As for the battery capacity, you need to do some calculations on:
  • How much power your motors will draw?
  • Decide how long flight time you want?
  • How much influence the battery weight should have on the total weight?
A good rule of thumb is that you with four EPP1045 propellers and four Kv=1000 rated motor will get the number of minutes of full throttle flight time as the same number of amp-hours in your battery capacity. This means that if you have a 4000mAh battery, you will get around 4 minutes of full throttle flight time though with a 1KG total weight you will get around 16 minutes of hover.

UIMU – Inertial Measurement unit

The Inertial Measurement Unit (IMU) is an electronic sensor device that measures the velocity, orientation and gravitational forces of the quadcopter. These measurements allow the controlling electronics to calculate the changes in the motor speeds.
The IMU is a combination of the 3-axis accelerometer and 3-axis gyroscope, together they represent a 6DOF IMU. Sometimes there is also an additional 3-axis magnetometer for better Yaw stability .

IMU Sensor from sparkfun electronics

Magnetometer

The accelerometer cannot sense yaw rotation like it can with roll and pitch, and therefore a magnetometer is sometimes used.
A magnetometer measures the directions and strength of the magnetic field. This magnetic sensor can be used to determine which way is south and north. The pole locations are then used as a reference together with the Yaw angular velocity around from the gyroscope, to calculate a stable Yaw angle.


Flight Controller :

Here is a comprehensive list of ready to go flight controller boards:


You can either make your own controller board by making use of Adruino board orlese make use of ready to fly controller board .

ADRUINO board from Sparkfun electronics
ARDUPILOT ATMEGA




Hard ware layout of Ardupilot

RC Transmitter

QuadCopters can be programmed and controlled in many different ways but the most common ones are by RC transmitter in either Rate (acrobatic) or Stable mode. The difference is the way the controller board interprets the orientations feedback together with your RC transmitter joysticks.
In Rate mode only the Gyroscope values are used to control the quadcopter. The joysticks on your RC transmitter are then used to control and set the desired rotation speed of the 3 axes, though if you release the joysticks it does not automatically re-balance. This is useful when doing acrobatics with your quadcopter as you can tilt it a bit to the right, release your joysticks, and then your quadcopter will keep that set position.



GPS , ULTRASONIC SENSOR , BAROMETER :

A GPS module talks to the satellite and retrieve accurate location information. We can use this information to calculate speed and path. It is especially useful for autonomous quadcopters which needs to know its exact position and which way to fly.
An ultrasonic sensor measures the distance to the ground, i.e. altitude. This is useful if you want to keep your quadcopter a certain distance from the ground without having to adjust the height it’s flying at constantly yourself. Most of these sensors has a range between 20cm to 7m.
When you gets higher, you might want to use a barometer. This sensor measures humidity and pressure to work out the altitude, so when the quadcopter is close to the ground (where these two factors doesn’t change much), it becomes ineffective. Therefore it is also common to use both of them at the same time.

GPS module from sparkfun electronics
ULTRASONIC SENSOR 



CONCLUSION







Thus an overview about selecting a controller board and building up your own quadcopters has been described shortly and precisely.
hope , you are now ready to build your own multirotors in your home.
GOOD LUCK !!!


Do check in regularly to see what we are doing in our project in overcoming days .................. :)