In 1907, the first quadcopter was created by inventors and brothers Jacques and Louis Bréguet. Their flight was nothing like today’s quadcopters, being only able to fly two feet from the ground and unable to steer (Luke Dormehi,2018). 36 years later, the first FPV drone was created by Boeing and US air force called BQ-7. Which was a bomber plane that was fitted with an Fpv(first-person view) system so that when the pilots ejected, it could be guided to the target (Paul Posea, 2022). The first time an Fpv system was used on a multirotor was in 2009 by David Windestal (currykitten ,2017). In 2011 through many different varieties of David’s multirotor, we started to see what resembles today’s FPV Quadcopter in figure 1.

Figure 1 FPV quadcopter

In figure 1.1, a Lithium Polymer Battery is what drives the Fpv quadcopter. Inside the green square, the 4s that you see represents the number of cells in the battery. And in figure 1.3 shows that each cell is connected in series. Each Lithium Polymer cell has a nominal voltage of 3.7 volts. That would mean that the total voltage of a 4s battery is 14.8 volts. The yellow box in figure 1.1 represents the battery’s capacity; mAH stands for milliamps per hour. 100c located in the blue box is the maximum discharge of current. Having a low “c” rating can result in a decrease in performance, similar to a car having low horsepower. There are two connectors on a Lithium Polymer Battery, as seen in figure 1.2. The balance wire in the orange box uses a JST-XH connector, which is primary use to monitor each cell separately. The main power cable that provides power for the whole drone uses an XT60 connector, seen in the white box. (Oscar, 2019)

The Frame is what gives the Quadcopter structure; it can dictate the size, strength, and how it would look like. The Frame was a Martian 2 220mm, as seen in figure 2.2. It features a wide X with a separate arms design. The frame is constructed out of carbon fiber due to its strength to weight ratio and rigidness. Figure 2.1 shows all of the parts that make up the frame. Parts A is the top plate of the main body, while part B is the bottom plate. Parts C are the arms, and due to the force being applied to them, they are made from 4-millimeter carbon fiber, which is thicker than the rest of the Frame. The part label D is the standoffs; this will give the space between the top and bottom plate. Parts labeled E are exchangeable; the Power distribution board can be used to deliver the battery power to multiple parts. F is the landing pads attached to the bottom of the quadcopter. G is the bolts and nuts you need to put the drone together. H is the standoffs to mount the flight controller, ESC (Electronic speed controllers), and video Transmitter. The final pieces with the Martian 2 frame are the mount for your fpv camera, label I.

Being an fpv quadcopter, a VTX (video transmitter) is essential for the fpv(first-person view) part. The AKK infinite DVR VTX has stackable mounting holes 30.5mm by 30.5mm, allowing it to be stacked with an all-in-one ESC and flight controller. As seen in figure 3.1 in a yellow box on the front side, there is the video transmitter module, which allows the VTX to transmit video on 5.8Ghz. In the red box is the flash memory module, which allows settings and configurations to be saved. Figure 3.2 shows the back of the VTX, and right away we notice the SD card slot. This is to record using the DVR function on it.  Above that, the MMCX connector to where an antenna would connect to. We have an IC (Integrated Circuit) highlighted by a yellow box to the left of the sd card.  This IC chip is an ultralow-power video decoder that converts analog to digital. On the left side, there are two buttons. The one highlight with the purple square changes the channel band and power settings. And the other one stops and starts the DVR function. Right near that button, is the microphone in a yellow circle. The blue squares highlight the capacitors, while the green squares highlight the diodes. And the last part is in the pink box, which is a voltage regular so the board can output 5 volts dc.

Under the VTC in the main stack would be the FC(Flight controller), which would be the brains of the aircraft. The FC in this quadcopter is the xrotor micro f4 g2, as the figures below show. In the middle of figure 4.1, in the red square, sits the IC for motion tracking. This device has a 3-axis gyroscope and a 3-axis accelerometer. Below that have solder point for UART (universal asynchronous receiver-transmitter) communication, which is used for serial communications to another device, such as connecting the receiver to it. On the left side of the board, there is a Micro-USB port so that the user can program and upgrade the FC. The connection on the top with a green square is connected to your Escs (electronic speed controllers). The Last port on the right of figure 4.1 is where the VTX is connected. The Rear of the FC houses three devices, as seen in figure 4.2. A yellow square shows the Sd card port to log any data during the flight. We have the OSD (on-screen display) IC to the left of the sd card port. This IC will overlay important flight data to the pilot’s video feed. Such as battery voltage, craft’s name, altitude, speed, and many more. Last but not least, surrounded by a Red Square, we have the stm32-f405 MCU (microcontroller unit). This MCU processes all the sensors and peripherals on the quadcopter.

                                     

Figure 4.1 Flight controller XRotor micro f4 G2 Top                   Figure 4.2 Flight controller XRotor micro f4 G2 Bottom

The last piece of the quadcopter stack is the Xrotor 45A 4in1 6s ESC. Many other quadcopters build use four individual ESCs, one for each motor. Having all the ESCs on a signal board can avoid wire clutter since you would use a jumper from the FC to the ESC board. And by moving the ESCs from the arms to the main stack, can avoid damaging them if there is a crash landing since the components wouldn’t be exposed. In figure 5.1, there is 24 MOSFETs (Metal Oxide Semiconductor Field Effect Transistor) on the board’s surface with a blue box around them. Above the MOSFETs is the port that would connect to the FC. If the 4in1is turned over, there is 8 IC chips have an essential role in any ESC. In red are the drive ICs, and in blue we have 32-bit MCUs. The drive ICs act as an interface between the MCU and motor, And the onboard MCUs communicate with the flight controller.

The part that allows the quadcopter to take flight is the motors. The type of motor that is used is a brushless motor as you can see in figure 6.1. Highlighted by a blue rectangle, The specific number that is printed on the motor identifies the size of the stator in millimeters. The size of the motor can be broken down in two measurements. The 22 in 2205, means that the stator is 22 millimeters width as seen in figure 6.2. And the 05 means 5 millimeters tall as seen in figure 6.3. Also the white arrow is pointing to the ball bearing. The last part of the brushless motor is the bell housing. The purple arrow in figure 6.4 shows were the magnets are located.

                                           

    Figure 6.1 Brushless motor                                                     Figure 6.2 motor stator wide

 References

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