Four axis aerial photography aircraft structure

1. Frame: the framework of an aircraft, containing various equipment.

2. Flight control: the brain of an aircraft, which contains accelerometers, gyroscopes, barometers, compasses and other sensors. It controls the speed of the four motors and then controls the attitude of the aircraft. Or add GPS to complete the functions of fixed height and fixed point return. Its essence is single chip microcomputer. Common flight controls include xaircraft superx, DJI Naza wkm A2, zero degree X4 Gemini, APM, MWC, QQ flight control, cc3d, etc.

3. Electric regulation: it is fully called electronic governor. Its input is DC and is usually powered by 2-6 lithium batteries. The output is three-phase AC, which can directly drive the motor. In addition, the aircraft model brushless electronic governor has three signal output lines for connecting to the receiver. The signal line can lead out a stable 5V voltage, which can generally be powered by 2-4 steering engines. The aviation model is to control the brushless electronic governor of the aviation model by remote control to adjust various flight postures and actions of the aircraft.

4. Brushless motor: a rotating magnetic field is generated by three-phase AC to drive the rotor to rotate. It has the characteristics of wide speed regulation, small volume, high efficiency and small steady-state speed error. The Kv value of brushless motor is defined as speed / V, which means the speed value of brushless motor with the increase of input voltage by 1 volt. However, for brushless motor, it does not only mean that the motor speed is strictly linear proportional to the voltage.

5. Remote control and receiving: as the name suggests; Used to receive and send instructions.

Alt4518531208971264 four axis aerial photography aircraft structure_ Making tutorial of aerial photography aircraft

Self made aerial photography aircraft tool foundation

In order to reduce unnecessary expenses, we recommend that you buy the following tools and consumables at one time:

Electric soldering iron, wire stripping pliers, wire cutting lead (ordinary pliers can’t hold the thick silica gel wire), a set of hexagonal socket, a set of screwdriver, small bench pliers, parts, horizontal bubble, heat shrinkable tube (4mm and 5mm are used more, depending on the situation), BB sound (it’s easy to lose, you can buy some for standby)

Aerial camera DIY steps tutorial

Step 1: build the fuselage

The central hub of the four axis aircraft is composed of two PC boards. Download the cutting and drilling template here, output it according to the original size, and temporarily paste it on the PC board. First make a mark with a plastic carving knife, and then drill with a 1 / 8 “drill bit.

Step 2: cut the support and drill holes

Saw four 10 “– 11” square wooden tenon supports. The shorter the support arm, the more agile the aircraft is, but the longer the support arm, the more stable the aircraft is. Drill two 3mm holes respectively, one 6mm from the tail end and the other 26mm from the tail end.

Step 3: assemble the fuselage

Fix the support arm on the PC board with screws. Use M3 × 25mm screw to cover the inner hole, M3 × 20mm screw shall be used to cover the outer hole. If the support arm looks good after being fixed with screws, “just apply screw sealant on the outer hole screws” and put on and tighten the nuts; The inner hole screw is gently sleeved with a nut and does not need to be fastened.

Step 4: connect the power core

The power core consists of six parts: four electronic speed controllers, power module and camera stabilizer control board. First, separate the XT60 male connector and the APM power module cable. Each red and black wire needs to be peeled off approximately ¼” The insulation sheath and the tail end of the stripped wire shall be tinned. Cut off the ring from both ends of the copper reducer, file the uneven edge, weld the positive terminals of six red wires on the inner ring, connect the corresponding six black negative terminals to the outer ring, wrap the inner ring with foam waterproof adhesive strip, and cover the outer ring. Finally, apply insulating adhesive to the whole center.

Connecting the motor and the electronic speed controller can be said to be a boring job. Buying the distribution board directly will be very easy, but it will occupy space and increase weight. I prefer to make my own distribution board. It can be completed by using two rings of tapered copper pipe. It also looks very fine and neat.

Step 5: drill the motor base

Here we teach you how to easily make your own landing gear with ordinary C-type pipe clamp. You can also buy cheap combined landing gear / motor base to streamline the manufacturing process.

If you plan to make your own landing bracket, you will need to install the motor directly on the bracket. First, mark each support and drill no obvious blind holes so that the motor shaft can rotate freely. 5 / 16 “bit is a good choice.

Step 6: install the motor

Bracket for cutting motor with two M3 × 20mm screws fix the motor and motor support on the tail end of the four rotor support. You must tighten each screw and ensure that the motor shaft can rotate freely. If it cannot rotate freely, check the groove of the four rotor support again, and finally grind the edge of the motor support with a file.

Step 7: add landing gear

Slide the power core between the two transparent plates, and then wind the power cord of the electronic transmission on the four supports. If the manufacturer of the motor is the same as that of the electronic transmission, there is likely to be a pre installed “bullet” connector. At this time, directly insert the motor wire into the transmission wire, and wrap the excess wire under the support. You can also weld wires directly to the electronic transmission control panel to simplify the structure. Fix the motor wire and electronic transmission wire, and then bind the remaining wires under the support with harness tape.

Cut the four C-clamps in half with wire cutters, put the J-shaped base aside, grind the cutting surface with a file, then grind two small grooves on both sides of the mounting hole, install the base at the tail end of each support, that is, the inner side of the motor frame, and the wire harness bypasses the just ground groove.

Step 8: install the shockproof base

Remove the water pipe snap ring of PVC hose and leave it for other topics. Using a pen art knife, cut two 3 / 4 “plastic rings from the rubber hose, align the inner hole screws protruding from the body, squeeze them with your thumb to form two dents, and then drill holes in the dents with a” ⅛ “drill bit, but do not drill through the other side. Fix the plastic ring on the machine body with M3 flat washer and nut. After adjusting the tightness, fix it with screw sealant.

Two shockproof bases are cut from the hose and then used to install the pan tilt and battery base to prevent the camera from being affected by the vibration of the propeller. By the way, make some space above to install the PTZ controller.

Step 9: install the camera and battery holder

Vientiane bracket and battery bracket are mainly composed of three groups of single L-shaped brackets. I call them bracket, roll axis bracket and pitch axis bracket.

Aluminum rod (1 / 8)“ ×¾”× 36 “) sawing into two 18” aluminum strips, and then sawing one of them into a 9 “aluminum strip, you will get a total of three aluminum strips. Each aluminum strip is folded into a right angle, and the bending radius can be increased to ( After the aluminum strip is bent, cut each support into the size of a plate.

Place the support in the correct installation position, mark and drill three holes with a radius of 1 / 8 “at the shorter end of the x-axis and y-axis supports. On the two supports, the small hole on the outside should be 3mm away from the tail end of the support, and the distance between the two small holes should be 9.5mm. Finally, use a step drill to expand the middle hole to 2” large, So that there is room for the motor shaft to rotate.

Use two M3 × Fix the bottom of the pan tilt motor on the support with 6mm screws, and then fix the top of the motor to the long side of the tumbling shaft support with another two screws.

Connect the bottom of the second motor to the other end of the turnover roller support, and the top of the motor is connected to the pitch shaft support in the same way.

Step 10: install the camera and battery

The four rotor I designed can balance the weight of 3S 2200mAh lithium battery and GoPro hero3 white. If you use other equipment, please ensure that your CG (center of gravity) is maintained in the center of the fuselage. The following demonstrates how to balance it.

Tip: Although the GoPro camera is quite fall resistant, you may also want to make a “fake” camera with the same weight and size, which can be installed on the aircraft for the first and subsequent test flights.

To make the pan tilt motor run smoothly, the camera must be balanced on both axes. Stick one side of the double-sided tape to your shirt to reduce its adhesion. Stick the other side of the tape on the pitching support, and then fix your GoPro on the side with weak viscosity. Slowly find out the balance. Just use two screws to fix the motor on the support and cut the motor support to reduce the weight. Two sets of shockproof devices can be made with thick rubber hose, or direction controller support and battery support can be made to prevent the camera from being affected by propeller vibration, and space for installing direction control board is reserved.

Turn the skeleton upside down so that the camera, bracket and battery are balanced at the central point of the shockproof device at the bottom of the skeleton. The assembled device will be adjusted around the skeleton until the entire four rotor device can strike a balance between your two fingers, and the balance point is located at the center of either end.

After finding the center of gravity, bond the two sets of harness straps to the shockproof device in a cross manner. Stick the devil felt tape on the bottom of the battery, and then fix the battery on the bracket. You can also add devil felt tape to the bracket and battery to provide additional fixing effect.

Step 11: set up avionics equipment

First arrange the flight control panel, receiver and other modules, and then install them on the fuselage. After finding out the placement method you are satisfied with, fix all parts to the fuselage with double-sided tape.

For the installation of flight controller, this time I use ardupilot Mega (APM) 2.6 with accelerometer launched by 3drobotics, which has a specific correct installation direction. Please align the arrow on the APM box directly in front of the four rotor, and then fix it with double-sided tape.

When installing the GPS / logic module, align the extension line at the bottom of the framework, and the arrow on the module must also be aligned to the front. Fix Tongyang with double-sided tape, and then connect the cable to the “GPS” connector of APM.

Starting from the front right, connect the ESC cable clockwise (looking from top to bottom) to the No. 1, 4, 2 and 3 connectors of APM.

Install the receiver along the APM and fix it with double-sided tape, and then connect its channels 1 to 5 to the corresponding input hole on the APM.

Step 12: install PTZ controller

The PTZ controller consists of two circuit boards: a larger control board and a smaller IMU sensor, that is, in the space reserved when installing the shockproof device.

Cover the surface of the support with foam tape to prevent short circuit between the solder joint and the exposed aluminum, and then fix the control board on it with harness tape. IMU can detect the direction of the camera, but it needs to be installed on the same aircraft. Install it on the bottom of the pitch axis support with double-sided adhesive tape, and then connect the cable back to the control board. Connect the 3 wires of pan tilt motor to the connector of the control board. Fix each wire with wire harness and reserve some wires so that the PTZ motor can rotate freely.

Step 13: install the software

The flight control panel, ESC and direction controller shall be calibrated and set before takeoff, which can be carried out according to the instructions attached to the device or the steps described on the line.

Step 14: add propeller

Before installing the propeller, paste some masking tape on the motor shaft to facilitate observation of their rotation direction. Viewed from above, motor 3 and motor 4 should rotate clockwise, while motor 1 and motor 2 rotate counterclockwise. If one of the motors is misaligned, only two of the three lines connected to ESC can be interchanged.

Warning: if you need to reverse one of the motors, just switch the motor control line instead of changing the ESC line. Never reverse connect the wires of ESC!

For stable flight, the most important thing is that the propeller needs to be balanced! There are some simple methods, but the most simple is to grind the thicker part of each piece of propeller until the propeller is balanced with the horizontal axis (only grind the whole surface, do not move to the leading edge or tail edge).

Once the propellers are balanced, install them on the motor shaft and tighten the screws. You will use two traditional “drag” propellers and two reverse “push” propellers. Motor 1 and motor 2 use towed propeller, and motors 3 and 4 use propulsion propeller (if you do not use APM flight controller, your propeller configuration may be different). After configuration, mark the number and rotation direction on each motor support for reference.

Make sure the propeller is balanced, all parts are firmly installed, and there is no reverse installation of propeller, gyroscope or controller. Check that all your radio modification settings have been reset to zero (if you need to modify, please do it through APM, not on the radio). Please wait until there is no wind for the first flight test of the self-made aerial camera aircraft.

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