Author: Chen Jianhua (net name: political commissar)
Classification and composition of radio remote controller
To understand radio remote control, we must first know what radio remote control is. Radio remote control is the use of electromagnetic waves, according to human will, to achieve long-distance wireless manipulation and control of objects. This wireless control method is called radio remote control.
The birth of radio remote control technology originated from radio communication technology. The original idea was to establish radio telegraph technology, and the invention of vacuum tube made the application and popularization of radio technology quickly applied to civil and military fields. In the First World War, the application of radio remote control was mostly in the military. When the torpedo is launched, the remote control torpedo is used to attack enemy ships and warships, which greatly improves the hit rate of the torpedo. In World War II, Nazi Germany installed a radio remote control system on a V-2 rocket and bombed London on a large scale. At that time, it can be said that radio remote control technology reached the extreme. Later, with the invention of transistor and the birth of integrated circuit, radio remote control technology reached a more perfect level. Now we know that missiles, satellites, space shuttles and other high-tech technologies are the crystallization of using radio remote control technology. It is no longer the only member in the military field, and our daily life can be said to be inseparable from radio remote control, such as remote monitoring, alarm, remote TV, remote toys and so on. So, how is the radio remote control divided? How does it work? Let's talk about this problem.
From the definition of wireless remote control, any control system that can realize wireless remote control should be regarded as a wireless remote control device. Therefore, we divide it into audio voice control, visible light control, infrared control, radio frequency electromagnetic wave control and carrier frequency electromagnetic wave control according to its transmitting and receiving spectrum frequency. According to the transmission modes of transmission and reception, there are regenerative, overweight duplex, heterodyne, superheterodyne, constant amplitude, amplitude modulation and frequency modulation. According to the carrier nature of transmission and reception, there are single audio remote control, double single audio remote control, pulse digital remote control, etc. According to the action types of transmission and reception, there are switch type, duty ratio type, pulse width type, pulse position type, composite type, time-division proportional type and mixed proportional type. According to the number of transmitting and receiving channels, there are single channel, double channel, four channel, eight channel and more than ten channel. If we divide the transmitting and receiving frequencies and wavelengths into long wave, medium wave, short wave or low frequency, high frequency and very high frequency; From the circuit composition of transmitting and receiving, there are discrete components, integrated circuits, analog circuits, digital circuits, hybrid circuits and so on. It can be said that in a broad sense, there are many types and ways of radio remote control technology, and we can't elaborate them one by one. In order to give you a deeper understanding of radio remote control, let's first introduce the composition and circuit of radio remote control equipment for the model.
The equipment of radio remote control model generally includes the following parts: remote control transmitter, remote control receiver, executive steering gear and electronic governor.
1. Long distance transmitter
It is what we call a remote control, which is used to control our car model or ship model. Because it has a long antenna outside, the remote control command is modulated and encoded by the internal circuit through the control switch and button outside the shell, and then emitted by the antenna through the high-frequency signal amplification circuit. At present, there are three kinds of remote control transmitters commonly used in the model: one is a small remote control transmitter, which is used to pack the keys; One is a portable rod remote control transmitter; The other is a remote transmitter with a pistol. The former remote control system is mostly a switch-type analog circuit, which is used by ordinary toy remote control car models, ship models or airplane models. The design and manufacture of the circuit are relatively simple, and the action instructions are "on" and "off". Although the number of channels can be large, the performance and distance of remote control are relatively low. The transmitters are rod-type and gun-type radio remote controllers, which are usually proportional. It is the most popular remote control operating system in dynamic simulation model. Due to the differences in modulation, coding and circuit composition, the cost performance of the two types is very different, so the prices are also different.
The proportional remote control lever transmitter has two joysticks, the left joystick is used to control the speed and braking (forward or backward) of the model car, and the right joystick controls the direction of the model car. The gun launcher uses a wheel (steering wheel) and a joystick similar to a pistol trigger to control the direction and speed respectively. In addition to these basic functions, some advanced transmitters also adopt advanced computer technology, adding many additional functions, such as storing the adjustment data of various model cars and ships, and using one machine for multiple purposes; With timing and lap counting functions, it is convenient for practice and competition; There is a large LCD screen, which can display the working status and various functions.
The basic principles of these two remote control transmitters are basically the same, but the shape and control mode of the remote control transmitter are different. Some people may ask: which type is better? In fact, the key is your own habits and your favorite control mode. Once the type is selected, it is best not to change the type of transmitter casually in the middle, which will change your control habits.
2. Remote control receiver
The remote control receiver is installed on the vehicle model or the ship model for receiving radio signals. It will process the radio signal from the remote transmitter, amplify, shape and decode the received signal, and convert the received control signal into audio signal or digital pulse signal which can be recognized by the executive circuit, and transmit it to other electronic components on the car model or ship model, such as the executive mechanism circuit and electronic governor circuit, so that our car model or ship model can complete the action instructions we send through these executive mechanisms. Because the receiver is installed on a model plane, car or ship, it is generally made as small as possible. It is as big as two matches and weighs only tens of grams, but most of them have high sensitivity and low performance. The receiving distance is hundreds of meters, and the good ones can receive radio signals transmitted thousands of meters away. Generally, the receiver should be used together with the transmitter, usually using a dedicated battery pack or using a 6-volt DC power supply (4 No.5 batteries).
3. Servo steering gear
The steering gear is an electromechanical device, which converts the signal from the receiver into mechanical action. Its main function is to convert the electrical signals received by the receiver into corresponding mechanical actions, so as to control the direction and speed. Servo steering gear can be divided into ordinary steering gear, powerful steering gear and micro steering gear according to different uses. Ordinary rudder can meet the requirements of general use; Powerful steering gear is usually used for large vehicles or operating mechanisms with large stress (such as steering mechanism of off-road vehicles); Micro steering gear is often used for model cars or ship models with small size and force.
However, some steering gears are often divided into individual units. This form of electromechanical separation is often used in non-proportional control circuits. In the early years, we often called it a driven wheel or an escape wheel, but it was actually a gear reducer. Now some switch-type remote control systems are often used. The proportional steering gear is very different from the usual one, which is not only small in size but also high in precision. It is a commonly used action actuator in proportional remote control system.
4. Electronic automatic governor
Electronic governor is what we usually call electric modulation, which is a power output control device specially used for electric remote control vehicles. It is an electronic control circuit, which is used to control the rotation speed and forward and reverse rotation of the motor on the car model or ship model. In other words, the electronic governor is an amplifying device, which receives the control signal from the receiver, and amplifies the received proportional signal into voltage and current that can be directly used by the motor to provide power for the motor to work. Compared with ordinary mechanical governor, it has the advantages of small volume, long service life, high efficiency and large output power. Some advanced electronic transmissions also use digital technology and high frequency operation, and have many functions such as programmed braking, automatic temperature control protection and automatic power off.