Now is a new era, whether it is people's life or social production are experiencing earth-shaking changes. People have also deeply realized the importance of industrial robots to the development of science and technology. The extensive application of industrial robots in industrial automation and intelligent manufacturing industry has also driven the development of other mechanical parts. Servo motor is an important part of industrial robot. The biggest difference between robot servo motor and common motor is introduced in detail.
What is the difference between a servo motor and an ordinary motor?
In short, the servo motor can achieve precise control, you can control its rotation, it can also feedback, through the encoder feedback to achieve a so-called closed loop, through the encoder feedback to determine whether it is rotating that much, so the control accuracy will be higher. Normal motors turn on the electricity, if there is no electricity then stop, in addition to turning, if you have to say it has any function, it is positive and negative.
The structure of the servo motor is no different from that of the ordinary two-phase ac asynchronous motor. The stator of the servo motor has two ac windings with an electrical Angle difference of 120 degrees, which are respectively called the excitation winding and the control winding. The rotor of the servo motor is the squirrel-cage winding of the common cage asynchronous motor.
The overall structure of the electric servo system of industrial robot is three kinds of closed-loop control: current loop, speed loop and position loop. In general, for the ac servo driver, the internal function parameters can be manually set to realize the functions of position control, speed control and torque control.
General servo motors used to drive robot joints require maximum power mass ratio and torque-to-inertia ratio, high starting torque, low inertia, wide and stable speed range.
The above is the difference between servo motor and ordinary motor. Servo motors have been widely used in industrial robots due to their high starting torque, large torque and low inertia. However, there are many different modes of servo motors. In order for the robot to perform at its best, attention must be paid to the relevant details in the selection.
Servo motor classification
According to the application situation of servo motor, servo motor can be divided into brushless dc motor and ac motor, also can be divided into 360 degrees of continuous rotation, straight line and fixed Angle motor. The servo motor usually consists of three wires: power, control and grounding. The appearance of the servo motor varies with the application scene. The most common RC servo motor is mainly used in robots, model cars and other small intelligent equipment, because it can be easily controlled by the microprocessor.
Dc servo motor
This type of motor usually has a separate dc supply on the winding and armature winding and can be controlled by controlling the armature current or the excitation current. Depending on the situation, excitation control and armature control have their respective advantages. Because of its low armature reactance, dc servo motors can be started or stopped accurately and quickly. They are mainly used in equipment that can be controlled by a single chip microcomputer or a computer.
Ac servo motor. In general, ac servo motors have more advanced designs and are equipped with better bearings. Ac servo motor has high working voltage, high torque and high precision. At the same time, ac servo motor can be completely controlled according to the requirements of the application scene. Ac servo motor is mainly used in robot, automation equipment, numerical control and other mechanical equipment.
Angle adjustable servo motor
Common servo motor, such as 180 degree servo motor, 90 degree servo motor, etc., this motor by setting a limit device on the gear mechanism to achieve the maximum Angle limit. It is widely used in remote control automobile, remote control ship model, remote control airplane, model robot and other products.
360 degree servo motor
- this motor is similar in appearance to a fixed Angle motor except that it has no fixed Angle and can rotate continuously for 360 degrees. The control signal intelligently controls the rotation direction and speed, but cannot set the fixed position, that is, the 360 degree servo motor cannot set the Angle. This kind of motor is mainly used for driving motor of mobile robot.
The linear servo motor is similar to the angular servo motor, but it has an additional gear to realize the reciprocating motion of the output shaft. This kind of motor is not very common. It is occasionally found in some high-end models.