The working principle of servo motor

时间2018/11/12 19:03:08

Since its introduction, servo motors have proven their usefulness in many industries. For many years, servo motors have been involved in completing big tasks. They may be small in size, but they are very powerful and energy efficient. With these characteristics, servo motors are widely used in remote control toy cars, airplanes, robots and various industrial equipment. In recent years, servo motors have also been used in industrial applications, online manufacturing plants, pharmaceutical services, robotics and food service industries.

The working principle of the servo motor

The working principle of the servo motor is relatively simple, but its work is more efficient. The servo circuit is built into the motor unit, and it uses a flexible shaft usually equipped with gears. The electrical signal controls the motor and also determines the amount of movement of the shaft. The internal setting of the servo motor is simple: small DC motor, control circuit and potentiometer. The DC motor is connected to the control wheel through a gear. When the motor rotates, the resistance of the potentiometer changes, and the control circuit can accurately adjust the movement and direction.

When the shaft is in the correct (ideal) position, the motor stops supplying power. If the axis does not stop at the target position, the motor keeps running until it enters the correct direction. The position of the target is transmitted through a signal line using electric pulses. Therefore, the speed of the motor is proportional to the actual and ideal position. When the motor is close to the desired position, the motor starts to rotate slowly, but when the motor turns to the farthest, the speed is fast. In other words, servo motors only need to complete their tasks as fast as possible, which makes them highly efficient devices.

There are usually two types of servo motors: AC motors and DC motors. DC servo motors are ideal for small applications, but they cannot handle large current surges. However, AC servo motors can cope with higher current surges and are widely used in industrial machinery. When it comes to price, DC motors are cheaper than AC servos, so they are used more. In addition, the DC motor is specifically designed for continuous rotation, which makes it ideal for robot motion.

With its unique features, servo motors can be used in many different applications. In radio-controlled aircraft, they are used to locate control surfaces such as robots, elevators, rudders, etc. In online manufacturing, servo motors are used in high repetition frequencies and require precise work.

Working principle of servo motor

servo mechanism is to make the output An automatic control system capable of following any changes in the input target (or given value). Servo mainly depends on positioning. Basically, it can be understood that when the servo motor receives 1 pulse, it will rotate the angle corresponding to 1 pulse to achieve displacement. Because the servo motor itself has the function of sending pulses, so every time the servo motor rotates At an angle, a corresponding number of pulses will be sent out. In this way, it echoes the pulse received by the servo motor, or is called a closed loop. In this way, the system will know how many pulses have been sent to the servo motor, and how many pulses have been received back at the same time. In this way, the rotation of the motor can be controlled very accurately, so as to achieve precise positioning, which can reach 0.001mm. DC servo motors are divided into brush and brushless motors. Low cost, simple structure, large start-up, wide speed range, easy control, maintenance is required, but maintenance is inconvenient (changing carbon brushes), causing interference and requiring environmental requirements. Therefore, it can be used in common industrial and civil occasions that are sensitive to cost.

The brushless motor is small in size, light in weight, large in output, fast in response, and high in speed. The inertia is small, the rotation is smooth, and the torque is stable. The control is complex, easy to realize intelligence, and its electronic commutation method is flexible, and it can be square wave commutation or sine wave commutation. The motor is maintenance-free, highly efficient, low operating temperature, low electromagnetic radiation, long life, and can be used in various environments.

2, AC servo motor is also a brushless motor, divided into synchronous and general Synchronous motors are all used, which have a large power range and can achieve great power. Large inertia, low maximum rotation speed, and rapid decrease as the power increases. Therefore, it is suitable for low-speed and smooth running applications.

3. The rotor inside the servo motor is a permanent magnet, and the drive is controlled by U/V/ W three-phase electricity forms an electromagnetic field. The rotor rotates under the action of this magnetic field. At the same time, the encoder of the motor feeds back signals to the driver. The driver compares the feedback value with the target value and adjusts the rotation angle. The accuracy of the servo motor is determined by the accuracy of the encoder (number of lines).

The functional difference between AC servo motor and brushless DC servo motor: AC servo is better Some, because it is sine wave control, the torque ripple is small. The DC servo is a trapezoidal wave. But DC servo is simpler and cheaper.




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