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Multi-rotor drone small knowledge summary one

Discussion in 'DroneVibes News' started by PilotEd, Dec 30, 2019.

  1. PilotEd

    PilotEd Member

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    Aug 9, 2019
    Sacramento, CA
    Posted by PilotEd, Dec 30, 2019 #1
    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?


    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.
     
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