Servo system is an important part of CNC machine tools, which is used to realize feed servo control and spindle servo control of CNC machine tools. The function of the servo system is to convert the command information received from the numerical control device into linear displacement or angular displacement of the execution part of the machine tool after power amplification and shaping. Servo system is the last link of CNC machine tools, and its performance will directly affect the accuracy and speed of CNC machine tools and other technical indicators. Therefore, the servo drive device of CNC machine tools is required to have good fast response performance, accurately and sensitively track the digital instruction signals sent by CNC machine tools, and faithfully execute the instructions sent by CNC machine tools, so as to improve the dynamic tracking characteristics and static tracking accuracy of the system.
The servo system consists of two parts: the driving device and the executing mechanism. The driving device consists of a spindle driving unit, a feed driving unit, a spindle servo motor and a feed servo motor. Stepper motor, DC servo motor and AC servo motor are commonly used driving devices.
The measuring element detects the actual displacement values of each coordinate axis of the NC machine tool and inputs them into the NC device of the machine tool through the feedback system. The NC device compares the feedback actual displacement value with the command value, and outputs the displacement command needed to reach the set value to the servo system.