The basic component of CNC machine tool -- servo and measurement feedback system

Servo and measurement feedback system

Servo system is an important part of CNC machine tool, which is used to realize feed servo control and spindle servo control of CNC machine tool. The function of the servo system is to convert the command information received from the CNC device into the linear displacement or angular displacement motion of the executing parts of the machine tool after power amplification and shaping. Because the servo system is the next step of the CNC machine tool, its performance will directly affect the precision and speed of the CNC machine tool and other technical indicators, therefore, the servo drive device of the CNC machine tool requires a good rapid response performance, accurately and sensitively track the digital command signal issued by the CNC device, and can faithfully execute the instructions from the CNC device. Improve the dynamic tracking characteristics and static tracking accuracy of the system.

Servo system includes driving device and actuator two parts. The drive device is composed of a spindle drive unit, a feed drive unit, a spindle servo motor and a feed servo motor. Stepper motor, DC servo motor and AC servo motor are commonly used drive devices.

The measuring element detects the actual displacement value of each coordinate axis of the CNC machine tool and inputs it into the CNC device of the machine tool through the feedback system. The CNC device compares the actual displacement value with the command value and outputs the displacement instruction required to reach the set value to the servo system.