Servo control method

Generally, there are three control modes for servos: [3] speed control mode, torque control mode, and position control mode.
Torque control
Torque control mode sets the magnitude of the motor shaft's external output torque through external analog input or direct address assignment. Specifically, for example, if 10V corresponds to 5Nm, when the external analog value is set to 5V, the motor shaft output is 2.5Nm: if the motor shaft load is less than 2.5Nm, the motor rotates forward; when the external load is equal to 2.5Nm, the motor does not rotate; when the external load is greater than 2.5Nm, the motor reverses (usually under gravity load). The set torque can be changed by instantly changing the analog setting, or by changing the corresponding address value through communication.
It is mainly used in winding and unwinding devices that have strict requirements on the material's force, such as winding devices or fiber optic pulling equipment. The torque setting should be changed at any time according to the change of the winding radius to ensure that the material's force does not change with the change of the winding radius.
Position control
The position control mode generally determines the rotation speed by the frequency of the external input pulse, and determines the rotation angle by the number of pulses. Some servos can also directly assign speed and displacement through communication. Since the position mode can have very strict control over both speed and position, it is generally used in positioning devices. Application areas include CNC machine tools, printing machinery, etc.
Speed ​​control
The rotation speed can be controlled by analog input or pulse frequency. The speed mode can also be used for positioning when there is an outer loop PID control with an upper control device, but the motor position signal or the direct load position signal must be fed back to the upper control for calculation. The position mode also supports direct load outer loop detection of position signals. At this time, the encoder at the motor shaft end only detects the motor speed, and the position signal is provided by the detection device at the direct final load end. The advantage of this is that it can reduce the error in the intermediate transmission process and increase the positioning accuracy of the entire system.