1. Apply for the program.

Controlled motors include servo motors, stepper motors, variable frequency motors, etc. in the field of automation. For parts requiring more precise speed and position control, servo motor drives are optional.

The converter + frequency conversion motor control method is a control method that changes the motor speed by changing the input power frequency of the motor. Usually just used to control the speed of the motor.

Comparing servo motors to stepper motors:

(a) Using closed-loop control servo motor, stepper motor open-loop control;

(b) Rotary encoder is used to measure the accuracy of servo motor, and stepper motor is used for step angle. At the general product level, the accuracy of the former can reach a hundred times the order of magnitude of the latter;

(c) The control method is similar (pulse or direction).

2. Power supply.

From the perspective of power supply, servo motors can be divided into AC servo motors and DC servo motors.

Both are better choices. For ordinary automation equipment, Party A will provide standard 380V industrial power supply or 220V power supply. At this time, a servo motor with corresponding power supply can be selected, eliminating the need for power supply type conversion. However, some equipment, such as shuttle boards of three-dimensional warehouses, AGV trolleys, etc., mostly use their own DC power supply due to their own mobility characteristics, so DC servo motors are generally used.

3. Brake.

According to the design of the action mechanism, consider whether it will cause the motor to move in the opposite direction when the power is turned off and stationary. If there is a reverse trend, you need to use a brake servo motor.

The electronically controlled Molson electromechanical low temperature servo motor is suitable for any extreme environment (high temperature, low temperature, outdoor severe cold environment), mainly used for special vehicles, automobile testing, low temperature cold storage...

4. Selection.

When making a selection, first determine the desired position and speed of the end of the mechanism, and then determine the drive mechanism. At this time, the servo system and the corresponding reducer can be selected.

When choosing, the following factors are mainly considered:

4.1. Strength and speed.

The power and speed required by the motor can be determined by the structural form and the main load requirements. It should be pointed out that the reduction ratio of the reducer usually needs to be selected in combination with the selected motor speed.

Due to the uncertainty of the friction factor and wind load factor of each transmission mechanism, for example, in the actual selection, the load is horizontal movement, and the formula P=T*N/9549 (the magnitude of the torque cannot be accurately calculated). However, in the actual application process, it is also found that the upper limit of the power required by the servo motor is often the acceleration and deceleration stage. Therefore, through T=F*R=m*a*R, the power of the required motor and the reduction ratio of the reducer can be quantitatively calculated (m: load mass; a: load acceleration; R: load rotation radius).

There are the following points to note:

(a) engine power margin coefficient;

(b) take into account the transmission efficiency of the institution;

(c) Whether the input and output torque of the reducer meets the standard and has a certain safety factor;

(d) Is it possible to pick up the pace at a later stage.

It is worth noting that in traditional industries, such as cranes, ordinary induction motors are used to drive, and there is no clear requirement for acceleration, and the calculation process adopts empirical formulas.

Note: If the load is running vertically, take the acceleration of gravity into account.

4.2. Inertia matching.

In order to achieve high-precision control of the load, it is necessary to consider the inertia matching of the motor and the system.

Regarding the question of why inertia matching is required, there is no unified statement on the Internet. The individual's understanding is limited, so it will not be explained here. Those who are interested can take the test by themselves and let me know. The principle of inertia matching is: convert the inertia of the system into the motor shaft, and the inertia ratio of the motor does not exceed 10 (Siemens); the smaller the ratio, the better the control stability, but the larger the required motor, the lower the cost performance. If there is any doubt about the calculation method, you can supplement the "Theoretical Mechanics" of the university by yourself.

4.3. Accuracy requirements.

Calculate whether the control accuracy of the motor can meet the load requirements through the calculation of the reducer and the transmission mechanism. It should be considered when the reduction gear or some transmission mechanisms have a certain return clearance.

4.4. Matching control.

This aspect is mainly to communicate with the electrical designer to confirm, such as whether the communication mode of the servo controller matches the PLC, the type of the encoder and whether the input data is required.