Built a quadcopter (I)

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ACQuad_med

INTRODUCTION – What is Arducopter?

ArduCopter is a platform for multirotors and helicopters, it’s easy to configure and to fly. It goes far beyond the basic multirotors radio found in the market today. The project is based on the ArduPilot Mega autopilot, created by DIY Drones community.

Unlike of the RF multirotors of the market, ArduCopter is a complete solution to unmanned aerial vehicle. It offers as much remote control as autonomous flight, adding interest points (waypoints), path planning and telemetry from ground control station.


The main features of ArduCopter are:

  • It’s the best of his class in RF flight mode, including level and altitude modes. It has a amazing “simple flight” mode which convert multi-rotor in to the best choice to begin flight. Just handling the radio, autopilot seeks ways to orient whatever their starting position, using the magnetometer aboard.
  • You have the option to keep the airborne position, using GPS and height sensors.
  • You can plan all missions with a wireless two-way connection. Schedule w aypoints , change the flight mode, even change gains control parameters, all this can be done from a computer, having the multirotor in the air.
  • Using sonar sensors, can be automated landings and takeoffs, and can even maintain flight storey. Without the sound, you can maintain altitude without much trouble heights over three meters.
  • The mission plans can be programmed with hundreds of landmarks, simply by click on the map in 3D GUI ground station. The multirotor follow the given points and returns to home to finish the route.
  • You can deploy camera controls, if you have a camera on board and keep it fixed pointing to an object from the floor.
  • No need to program anything. It has an interface easy to use desktop with visual displays, complete ground station, and a planner of missions, which are configured by clicking on the computer screen.
  • Compatible with Windows, Mac and Linux. In Windows you have the graphical configuration utility Mission Planning and other operating systems, it has a command line interface. Once the ArduCopter is set, you can choose from three ground stations, including QGroundControl , which runs on all three operating systems.
  • Compatible with leading industry standards in robotics, such as “ Willow Garage’s Robot Operating System ” or the communications protocol MAVLink . This ensures remain at the forefront of aerial robotics, from the multi-UAVs to support Android .


The ArduCopter project will be implemented in two variants. multirotores (quadcopters, tri-helicopters, hexacopters, etc) and traditional helicopters

MOUNT

You can have the complete kit with everything you need. Also need a LiPo battery, a remote radio control and a welder.

body quadcopter

Components

  • The structure for ArduCopter
  • The four engines
  • The four ESC
  • The power distribution board
  • The kit ArduPilot Mega (flight controller, red plate and shield, the IMU, blue plate)
  • A magnetometer
  • The kit of telemetry
  • The Sonar XL-MaxSonar EZ0
  • The LiPo battery of 2200 mAh or higher, with charger, power supply yalgunos
  • A radio-control. It takes one of at least six channels.

 pieces

Assembling the APM and IMU

First, solder the pins angled 3×16 in APM plate ( ArduPilot Mega ) to the connectors on the radio control.

imu

 

Then cut the pins necessary to adjust the IMU to the APM.

disassembled

Pin male strips are assembled in each row pin female and necessary trimmed:

cutting

We pairs of pins as the figure below.

cut

Now solder the male to the plate ArduPilot Mega as shown in the following figures.

soldier

The procedure is repeated with the IMU, pins female soldiers all pins are soldered carefully both plates are assembled.

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GPS

The module MediaTek MT3329 GPS 10Hz is connected to the APM board as shown below.

gps

Magnetometer

magnetometer

Flying a multirotor when is fixed at a certain height, the GPS, which can only calculate the position when moving forward, is insufficient to correct the drift in the spin orientation ( yaw ). For these cases, you need to add a magnetometer, which is able to correct the deviation, even when the vehicle is not moving. We work with the magnetometer HMC5843 Triple Axis .

In addition, when using the GPS, magnetometer is required to know which direction to move the multirotor to correct for changes in length or latitude.

The HMC5843 magnetometer is connected to the IMU by the I2C port. The cables “ SCL ‘,’ SDA ‘,’ +5 V ‘,’ Earth ” must correspond the same bolts in the magnetometer, as shown below.

magnetometer Connection

It is recommended to thread the wires through the hole before welding.

soldier

I2C is connected to the IMU

connected

Make sure that the solder bridge magnetometer is 5 V before connecting.

voltage

Assembling the structure of cuadcópter

mount

assembled structure

Sunstroke and connection of the power distribution board (PCB)

We need to produce our own energy distribution board. To do this we will have a virgin double-sided board and get sunstroke in laboratories.

pcb

We printed circuits onionskin and after etch the board, we cut and make the necessary holes.

PCB2

Here we welding the four pins required to connect the ESC and the solder connections which are required for correct operation thereof, as shown in the following figures.

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Engines

Engines are screwed in the respective holes of the structure.

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Selecting the alignment

You can get setup in “+”, which means the cuadcópter moves aligned with one arm forward, or get a configuration “x” where the APM is pointing between the two front arms.

Two types of propellers is needed, a extractor and a push . The propellers pusher go clockwise and extractor go anti-clockwise. If there is confusion with the names or positions of the helices, ensure that air flows down when the engines are started.

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Configuration “+”

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Configuration “x”

The choice of the direction of rotation of the propellers is made in the form of connecting cables between the motors and ESC.

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Tuning radio-control module

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A RC of at least six channels is required.

  • Channels 1-4: The basic flight control ( r oll, pitch, throttle, yaw )
  • Channel 5: Selection Mode (manual, automatic, altitude hold, etc.)
  • Channel 6: Not currently use
  • Channel 7: To calibrate the throttle in the air
  • .

  • Channel 8: Used for aircraft, not for multirotores
  • .

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Sonar

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The use of sonar low altitude MaxSonar to maintain the level and prevent collisions is recommended. Below 3 meters high, the sonar is mainly used to maintain altitude; and above 3 meters, the barometric pressure sensor periodically calibrated by the GPS is used. In particular, to keep up the sonar MB1200 XL-MaxSonar EZ0 due to its proper width and high power beam is recommended.

For connection, place the probe in the structure of cuadcópter, looking down and carefully that there is nothing between the sensor and the ground. Land, voltage and pin 3 in the corresponding position of the IMU are connected according to the following image:

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Telemetry Modules XBee-Pro Wireless

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Add wireless telemetry to cuadcópter is not complicated and can extend the capabilities of multirotor considerably. We recommend using modules Xbee Wireless, which have a range of more than 1.5 kilometers.

We want to mount the module XBee in front of multirotor. For this welding start in the IMU four pins as shown below.

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Now, turn the four pins with care 90 degrees to make them stand out from the plate by the side of it.

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We connect the adapter XtremeBee to use the XBee 2.4GHz, to these pins.

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The adapter must be in “ Master ” (check the TX and RX pins).

When computer (landside) is required to connect the other adapter XtreamBee, simply by USB cable. The adapter must also be in the “ Maestro” mode.

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continued in next episode …

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