Before type selection calculation, the first thing to determine is the position and speed requirements of the end of the mechanism, and then determine the transmission mechanism. At this time, the servo motor and the corresponding reducer can be selected.

In the selection process, the following parameters are mainly considered:

Servo motor power and speed

According to the structure and the speed and acceleration requirements of the final load, the power and speed required by the motor are calculated. It is worth noting that, in general, it is necessary to select the reduction ratio of the reducer according to the speed of the selected motor.

In the actual selection process, for example, the load is horizontal motion, because of the uncertainty of friction coefficient and wind load coefficient of each transmission mechanism, the formula P = t * n / 9549 often can not be calculated clearly (unable to accurately calculate the size of torque). In practice, it is also found that the maximum power required by the use of servo motor is often in 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 (M: load mass; a: load acceleration; R: load rotation radius) can be calculated quantitatively.

The servo motor has the following points to pay attention to:

a) The power surplus coefficient of the motor;

b) The transmission efficiency of the mechanism is considered;

c) Whether the input and output torque of the reducer meet the standard and have a certain safety factor;

d) Whether there is the possibility of increasing the speed in the later stage.

It is worth mentioning that in traditional industries, such as cranes and other industries, ordinary induction motors are used for driving, and there is no clear requirement for acceleration. Empirical formula is used in the calculation process.

Note: when the load is running vertically, the acceleration of gravity should be taken into account.

4.2 inertia matching

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

For the problem of why inertia matching is needed, there is no unified statement on the Internet. Personal understanding is limited, so I will not explain it here. Interested friends can make their own research and let me know. The principle of inertia matching is: considering that the inertia of the system is converted to the motor shaft, and the inertia ratio of the system to the motor is not greater than 10 (Siemens); the smaller the ratio is, the better the control stability is, but a larger motor is needed, and the cost performance is lower. If you don't understand the specific calculation method, please make up for the University 'theoretical mechanics'.

4.3 accuracy requirements of servo motor

Calculate whether the control accuracy of motor can meet the requirements of load after the change of reducer and transmission mechanism. There is a certain return clearance in reducer or some transmission mechanism, which needs to be considered.

4.4 control matching

This aspect is mainly to communicate with electrical designers to confirm, such as whether the communication mode of servo controller matches with PLC, encoder type and whether it needs to export data, etc.