UAV is the abbreviation of Unmanned Aerial Vehicle. It is an unmanned aircraft using radio remote control equipment and its own program control device, including unmanned helicopters, fixed-wing aircraft, multi-rotor aircraft, and unmanned airships.

1. Multi-rotor drone small knowledge summary one
Basic articles
1. What is a drone?
UAV is the abbreviation of Unmanned Aerial Vehicle. It is an unmanned aircraft using radio
remote control equipment and its own program control device, including unmanned helicopters,
fixed-wing aircraft, multi-rotor aircraft, and unmanned airships. , Unmanned paraglider. In a
broad sense, it also includes near-space vehicles (20-100 km airspace), such as stratospheric
airships, high-altitude balloons, solar drones, and so on. From a certain perspective, drones can
perform complex aerial flight tasks and various load tasks under unmanned conditions, and can
be regarded as "air robots".
2. What is flight control?
The so-called drone flight control is the drone's flight control system, which mainly includes
gyroscope (flying attitude perception), accelerometer, geomagnetic induction flight control, air
pressure sensor (rough control of hover height), ultrasonic sensor (low altitude) Precise control or
obstacle avoidance), optical flow sensor (precision determination of horizontal position when
hovering), GPS module (rough positioning of horizontal position and height), and control circuit.
The main function is to automatically maintain the normal flight attitude of the aircraft.
Remote control articles
1. Remote control and receiver?
An airplane aircraft needs to be controlled by a device. This device is a remote control. The
corresponding aircraft needs a device that can receive commands from the remote control. This
device is a receiver. The remote controller and the receiver communicate via radio waves. The
commonly used radio frequencies are 72Mhz and 2.4Ghz (in the early days, 72MHZ long wave
was mainly used, and now technology advances mainly use 2.4GHZ short wave). The remote
controller can set some flight parameters, such as the forward and reverse of the throttle, the
sensitivity of the joystick, the neutral position adjustment of the steering gear, the function
definition of the channel, the recording and reminder of the aircraft time, the setting of the liver
function, and the advanced model Battery voltage and current data returned and so on.
2. Crystal and frequency?
When using a 72MHz remote control, due to the openness of radio waves, from 72.010MHz to
72.99MHz in the 72Mhz band, a channel is allocated every 20kHz, a total of 50 channels, so that
there is one each for the remote control and the receiver A frequency generator (crystal oscillator)
with the same frequency allows the receiver and the remote control to communicate at the same
frequency. With the advancement of technology, the 2.4Ghz remote control no longer needs to
be paired with a single crystal. It only needs to directly perform frequency calibration between
the remote control and the receiver, so that the remote control and the receiver can directly
establish a communication connection. For home use remote control toys, due to requirements
and price reasons, 40MHZ and 27Mhz are mainly used. Sometimes the remote control with the
same frequency can be universally operated with each other. This problem also exists on the
aircraft model. Therefore, when the 72Mhz remote control was used early, When you arrive at
the flying field, everyone will first understand each other's remote control frequency bands to
avoid miscommunication operations. 2.4Ghz, now commonly used, is not needed.
3. Definition and requirements of remote control channel?

2. The remote control will have several channels to control, commonly known as several channels.
For example, the common SkyFly 6 is six channels. An airplane aircraft, some of which need to be
manually controlled by remote control. For example, power control, commonly known as throttle,
elevator, rudder, aileron, flaps, landing gear, smoke puller, lights, etc., each item needs a separate
channel to control, but some items need to be very precise and non- Level operations, such as
throttle, lift, direction, aileron, and some item controls are fixed to several gear operations, such
as flaps, landing gear, lights, etc. For the above remote control, there are rocker and joystick
definitions, such as throttle, Lift, direction, ailerons are operated with joysticks, and flaps, landing
gear, lights, etc. are operated with joysticks.
4. What are the differences and definitions between Japanese and American hands?
Because the areas where the model activities were carried out earlier were in Japan and North
America, the functions of the two joysticks and four channels in the controller are different in
these two areas. As in Japanese hands, the left stick: the up and down elevator, the left and right
are rudders; the right stick: the up and down are throttle rudders, and the left and right are
aileron rudders. American hand left stick: throttle up and down, left and right rudder; right stick:
up and down, elevator, left and right aileron rudder. This is mainly based on personal preferences.
It is like driving a car with a left rudder, mainly in mainland China and North America, a right
rudder, mainly in the Commonwealth countries and some regions, such as the United Kingdom
and Hong Kong. From the perspective of theoretical safety, the left rudder is better in the
northern hemisphere, but more of it is mainly a matter of habit formation. The advantages and
disadvantages of the American hand and the Japanese hand are usually the difference in
operating speed in the operation of some extremely difficult movements. Usually, everyone uses
more Japanese hands for the fixed-wing and more American hands for the helicopter.
5, the choice and brand of the remote control?
The remote controls are imported and domestic brands. The domestic ones are Tiandifei,
Walkera, FlySky, FrSky, RadioLink, and Futaba (Japan), JR (Japan), ROBBE (Germany), Graupner
(Germany), the early domestic electronic level was poor, and the quality of the control was
average. Now the quality of domestic control is quite stable, and the cost is high. The Chinese
interface of the device is easy to operate and affordable, and the matching receiver is also cheap.
A set of remote control and receiver can not exceed 1,000 yuan. Choose Futaba T8FG 14SG, JR 9X
XG7XG11, the price set starts from 1500, and the receiver is expensive. Beginners can start with
FS-I6 or FrSky Tanaris X9D, and then upgrade according to the needs of the aircraft they are
playing. Usually, fixed-wing aircraft and helicopters only need six channels to control, and even
early four channels can be used, that is, the throttle. , Aileron, lift direction.
6. What is the difference between PCM and PPM?
This mainly refers to the encoding method of the remote control. PPM is equivalent to analog
transmission. The radio waveform is directly transmitted to the receiver and transmitted to the
servo for execution. The receiving needs to have decoding and restoring process, which is passed
to the servo for execution. Similar to the previous analog signal transmission television and the
current digital signal television.
Third, the motor ESC
1. Brushed motor?
A: Brushed motors consist of a stator and a rotor. The stator has magnetic poles (winding or
permanent magnet), and the rotor has windings. After the power is applied, a magnetic field

3. (magnetic pole) is also formed on the rotor. There is an included angle that makes the motor
rotate under the mutual attraction of the stator and rotor magnetic fields (between the N and S
poles). Changing the position of the brush can change the included pole angle of the stator and
rotor. The direction of the magnet, which changes the direction of rotation of the motor. This
brush is a brush, also called a carbon brush. Disadvantages Power consumption, carbon brush
wear, bulky, short life.
2. Brushless motor?
A: The brushless motor also has a rotor and a stator. The rotor of the brushless motor is
permanent magnetic steel. It is connected to the output shaft together with the casing. The
stator is a winding coil. Therefore, it is called a brushless motor. By changing the alternating
frequency and waveform of the current wave input to the stator coil of the brushless motor, a
magnetic field rotating around the geometric axis of the motor is formed around the winding coil.
This magnetic field drives the permanent magnet on the rotor. The magnetic steel rotates and the
motor rotates. The performance of the motor is related to the number of magnetic steel, the
magnetic flux strength of the magnetic steel, and the input voltage of the motor. It also has a lot
to do with the control performance of the brushless motor. Direct current and current require the
electronic governor to change it into a 3-phase alternating current. It also needs to receive
control signals from the remote control receiver to control the speed of the motor to meet the
needs of the model. In general, the structure of the brushless motor is relatively simple, and it is
really the brushless electronic governor that really determines its performance, commonly
known as the ESC. Advantages: long life, power saving, convenient later maintenance, no need to
replace the carbon brush.
3. What is an ESC?
Answer: Because the brushless motor has canceled the carbon brush structure, it needs
components that can replace the function of the carbon brush. This is the ESC. The ESC is
responsible for converting DC power to three-phase power and controlling its voltage and current
according to needs. The brush motor achieves the required speed output.
4.XXA for ESC?
Answer: XXA often mentioned in ESC refers to how much the ESC can stably adjust the output
current. For example, 60A is the maximum stable output current of 60A amps. Do not use it
beyond the standard, it will cause ESC to burn out.
5.Motor model
Answer: The motor model mainly includes KV value and motor code. Conventional models such
as brushless motors 2212/2217/2208. 22 refers to the motor coil stator diameter; 12/17/08
refers to the motor coil stator length. Compared to 2216 and 2212, the power of 2216 is stronger
than in 2212. KV refers to how much the motor speed increases when one volt is applied. KV2000
refers to the motor at 20000 revolutions per minute when the voltage is 10 volts. The meaning of
this parameter is: can help you judge the characteristics of this motor, high KV motors are violent,
low internal resistance, large current, high power, fast speed or high power bursting out at the
same voltage has a good limit speed, However, due to the design and material limitations of the

4. motor, there will be an upper power limit. Generally speaking, high KV with small high-speed
propellers and low KV with large low-speed propellers are similar to driving. Often the speed is
relatively low.
Fourth, balance filling
1. Why do you need to balance charging?
A: The power battery of the aircraft model is generally used by connecting several cells in series,
such as 3S 2200, which is connected by three 3.7 volts 2200 mAh cells in series. Because the cells
themselves have differences, such as internal resistance And the capacity, not every 2200 mAh
battery, the actual capacity must be exactly 2200, generally, there is a difference of 10-50 mA, the
same is true of internal resistance, such a difference in series discharge and When charging, the
actual voltage of the monolithic battery cell will be different. This will cause damage to the
battery life and capacity in the long term. Therefore, when charging, we generally charge the
individual battery cells in series first, and then according to the separate battery In the case of
core voltage, charge it separately to keep the voltage of each single battery cell consistent.
2. What is the function of the balance head?
Answer: The balanced head is used on the battery to measure the overall and single-cell voltage
and perform balanced charging.
3. What is the BB ring?
Answer: BB ring is actually a small device for voltage measurement and low-voltage alarm with
buzzer. It can measure the overall battery voltage and single-chip voltage situation through the
battery's balanced head and can set the low-voltage alarm to beep. Sounder.
Five, FPV articles
1. What is the function of the PTZ?
A: Due to the presence of high-frequency vibrations in the aircraft, if some equipment is directly
mounted, such as a camera, the image will be shaken and blurred. If the helicopter is mounted
through the gimbal, the vibration compensation function of the gimbal itself can offset the
vibration of the aircraft. Impact on the camera or other equipment, and can operate the
equipment mounted on it, there are two axes, three axes, mainly in the controllable direction,
such as horizontal, up and down.
2. What is the image transmission mentioned in aerial photography, and what is the difference
between 5.8G and 1.2G?
Answer: Image transmission is image transmission, which basically consists of on-board camera
and transmitter, ground receiving and screen. The main frequencies used are 5.8GHZ and 1.2GHZ,
and some use WIFI frequency. Using 5.8GHZ for short distances and 1.2GHZ for long distances,
DJI ’s flying cameras use WIFI. Using a mobile phone, you can communicate with unmanned
aerial cameras in the air to achieve camera operation. Among them, the power of the transmitter
is different from 200 to 1000 milliwatts. It is mainly determined according to the distance
required for wireless transmission. The larger the power, the better the signal. The commonly
used wireless router in the home usually has only a few milliwatts.

5. 3. What is the common shooting equipment for multi-axis fixed-wing aerial photography?
A: For aerial photography, the commonly used equipment is Micro Single, Gopro, Mountain Dog
SUPTIG, 808, Eagle Eye, and even the driving recorder. The price and performance are different.
High-speed can use a professional G0PRO camera, if you need a small size, you can choose 808,
the picture quality is not high, you can choose the driving recorder to modify. In order to pursue
the picture quality, there is an SLR camera mounted on the gimbal, as needed. Black Dog Silver
Dog White Dog corresponds to the three color versions of G0PRO three generations.
BY:MMC-www.mmcuav.com