Servo control practical application

Servo control system is an indispensable part of CNC machine tools. Its task is to convert CNC information into machine tool feed motion, so as to achieve precise control. Since CNC machine tools have high requirements for product processing, the servo control system used is very critical.
The servo control system used in CNC machine tools has the following advantages: high precision. The precision of the servo system refers to the accuracy of the output to reproduce the input. Including positioning accuracy and contour processing accuracy; good stability. Stability means that the system can reach a new or return to the original equilibrium state after a short adjustment process under the given input or external interference. Directly affects the accuracy and surface roughness of CNC processing; fast response. Fast response is an important indicator of the dynamic quality of the servo system, which reflects the tracking accuracy of the system; wide speed regulation range, the speed regulation range can reach 0-30m/min; low speed and high torque, the servo control of the feed coordinate belongs to constant torque control, and this torque must be maintained throughout the speed range. The servo control of the spindle coordinate is constant torque control at low speed, which can provide a large torque, and constant power control at high speed, with a sufficiently large output power.
The main permanent magnet synchronous AC servo system used in machine tool feed servo is of three types: analog, digital and software. Analog servo has a single purpose and only receives analog signals. Position control is usually implemented by the host computer. Digital servo can achieve multiple uses, such as speed, torque and position control. It can receive analog instructions and pulse instructions, and various parameters are set in digital mode, with good stability. It has rich self-diagnosis and alarm functions. Software servo is a fully digital servo system based on a microprocessor. It implements various control methods and monitoring programs of servo motors of different specifications and powers in software. When in use, the user can set the code and related data to automatically enter the working state. It is equipped with a digital interface. When changing the working mode or changing the motor specifications, you only need to reset the code, so it is also called a universal servo.
AC servo has occupied a dominant position in machine tool feed servo and has been continuously improved with the development of new technologies, which is specifically reflected in three aspects. First, the power electronic devices in the system power drive device are constantly developing towards high frequency, and intelligent power modules are becoming popular and applied; second, the maturity of microprocessor embedded platform technology will promote the application of advanced control algorithms; third, the promotion of networked manufacturing models and the maturity of fieldbus technology will make network-based servo control possible.