What exactly do you need to prepare for the formation of a self-propelled drone traverser?
The structure of the drone traverser is a compulsory course for you to enter the pit.The crossing aircraft needs power systems such as frame, battery, motor, and rotor to complete the flight. In addition, the signal control of the crossing plane depends on the remote control system and FPV image transmission system.
Flight control is referred to as FC for short.
The drone traverser’s flight control is the brain of the aircraft, integrating microprocessors and multiple sensors, including acceleration sensors (detecting flight attitude), gyroscopes (detecting rotation speed), etc. The drone traverser’s flight control obtains signals, processes and outputs signals, sends instructions to various parts of the aircraft, coordinates them to complete their work, and controls various flight attitudes.
The drone traverser’s flight control usually comes with firmware. Players can set various parameters by configuring software (ground station). At present, the most mainstream firmware configuration software of the drone traverser is the Betaflight ground station.
Electronic Speed Control
Electronic Speed Control, also known as ESC, is an essential component of the drone traverser. The ESC can analyze the flight control signal and drive the motor to adjust the speed of the drone traverser. In addition, the ESC serves as the power assembly of the drone traverser, as the battery can only supply power to the flight control system after the ESC is depressurized.
The motor, also known as the “engine,” is a crucial component of a drone traverser. It is an electromagnetic device that converts or transmits electric energy according to the law of electromagnetic induction, and acts as the power source for the machine. The motor speed determines the drone’s flight performance. Typically, the manufacturer’s instruction manual will recommend a specific motor configuration for the traverser. For instance, motors of 22, 23 series are typically used for 5-7 inch drones, while 11, 13, 14, 15 series motors are commonly used in drones less than 3 inches. The Kv value is a critical performance parameter of a brushless motor and helps determine the motor’s characteristics. The Kv value is the motor’s speed (no-load) calculated as KV value x voltage. For example, a motor with a KV2300 rating means that when the voltage increases by 1 volt, the motor’s idle speed increases by 2300 rotations per minute. If the input voltage is 10 volts, the motor’s idle speed would increase by 23,000 rotations per minute.
When the speed reaches a certain level, airflow will differ between the upper and lower wings. The airflow below is more potent than above, naturally lifting the crossing machine.
The principle of propeller generating thrust is the same as that of the fixed-wing wing. We can imagine the propeller as a wing, and the propeller is infinitely enlarged. Each plane of the propeller is a wing relative to the tangential flow. The lift generated by the airfoil will pull the propeller forward, the first force generated by the propeller. The better the shape of the propeller, the greater the power. The component force brought by the upstream airflow in the propeller’s rotation is the second force generated by the propeller, and the greater the pitch.
The motor and blade are the sources of lift of the traverser. The engine and propeller need to be selected according to the size of the crossing machine. For example, the most conventional 5-inch crossing machine can be matched with a 1600KV~2700KV motor.
The frame is the skeleton of the drone traverser. An excellent structure needs to consider weight, strength, and appearance.
The conventional 3-5 inch machine is generally made of carbon fiber board. The micro culvert machine will use resin plastic as the frame or culvert material. In addition, flexible 3D printing material (TPU) and EVA sponge are also widely used to make various supports and buffers.
Battery and capacitor
The battery is like the lifeblood of a vehicle, providing the power needed to keep it moving. The lithium polymer batteries used in traversal machines can discharge power in the kilowatts range, which can create a strong induced voltage. To stabilize the voltage and reduce electromagnetic interference, a capacitor is often connected in parallel with the battery.
Remote Control System
The remote control system sends commands from the ground to the aircraft, and controls motor speed after processing signals. It consists of a remote control on the ground and a microcomputer, which supports various functions and even simple programming like the flight control system. The remote controller has firmware and also supports manual brushing.
HF signal transmitter – ground
The remote control is responsible for wirelessly transmitting signals to the aircraft using a signal transmitter. Most remote controls have a built-in transmitter that is compatible with multiple protocols. The transmitter’s wireless protocol and frequency must match the receiver’s for it to work. Some remote controls have external transmitter slots on the back to increase compatibility. The signal transmitter’s expected frequencies are 915MHZ, 2.4GHZ, 5.8GHZ, etc. A lower frequency results in better signal quality but requires more power. It’s essential to note that the remote control’s signal frequency cannot be in the same range as the image transmission frequency, or severe interference will occur.
Receiver and antenna – sky
The receiver is a crucial component of the aerial system that receives wireless signals from the remote control transmitter. To function properly, the receiver’s wireless protocol and frequency must match the transmitter’s. Once the receiver receives the wireless signal, it then sends the received information to the main control board through the hardware protocol. However, the specific configuration method for the receiver will depend on the system and won’t be explained here.
The FPV system can synchronize the images in the sky to the first angle glasses of the operator. At present, FPV system has two technical schemes, digital signal and analog signal.
Camera – Sky
The camera on the drone can capture real-time image information and transmit it to the flight controller for image overlay, also known as OSD (On-Screen Display). The OSD allows the operator to view important flight information, such as power level, flight time, and flight attitude, which can be set up on the ground station.
Image transmitter (VTX) and antenna – sky
The image transmission receiver can receive the image signal from the transmitter in the sky, and some FPV devices will have a built-in receiver. The directivity and sensitivity of the external receiver will be better. The structure of the antenna will also directly affect the signal strength.
FPV glasses/screen – ground
The pilot uses the FPV glasses to see the live video feed from the camera mounted on the drone. By seeing what the drone “sees”, the pilot can control the movement and direction of the drone. The FPV system operates similarly to the radio control system. After the receiving channel is set, the live video feed from the drone can be monitored in real-time. This allows for more precise and accurate control of the drone while in flight.