In modern printing machinery, the demand for high-precision and high-speed printing puts forward higher requirements for the control accuracy of equipment. Among them, the synchronous servo valve is the key control element in the hydraulic system, and its accurate synchronous control is very important to ensure the printing quality. This paper will discuss how to realize the coordinated control of synchronous servo valve in printing machinery.
First, the basic principle of synchronous servo valve
Synchronous servo valve is a device that can accurately control the flow and pressure in the hydraulic system according to the input signal. It is usually composed of electro-hydraulic servo valve and feedback mechanism, which can realize multi-axis synchronous control under high dynamic response. In printing machinery, synchronous servo valve is widely used to control key components such as printing cylinder, paper feeding device and ink roller pressure adjustment.
Second, the necessity of synchronous control
The printing process requires strict synchronous operation between printing units, otherwise it will lead to overprint errors, blurred images and other problems. Especially in high-speed printing, if there is a slight time difference or position deviation between the axes, it will seriously affect the quality of printed matter. Therefore, adopting synchronous servo valve for precise control is an important means to realize high-quality printing.
Third, the technical means to realize synchronous control
1. Closed loop control technology
Using feedback devices such as encoder or grating ruler, the actual position and speed of each axis are fed back to the control system to form a closed-loop control loop. The servo valve is instructed by PLC or motion controller to realize dynamic adjustment and ensure the synchronization of each shaft.
2. Master-slave control structure
In a multi-axis system,
one main axis can be set as the reference axis, and other slave axes can follow according to the position of the main axis. The deviation is calculated by the controller, and the flow rate of the servo valve is adjusted to keep the slave shaft synchronized with the main shaft.
3. Cross-coupling control strategy
Cross-coupling control is an advanced multi-axis synchronization algorithm. By establishing the coupling error model between the axes, the output of each axis servo valve can be adjusted in real time, thus effectively reducing the synchronization error and improving the system stability.
4. Digital bus communication
High-speed bus communication protocols such as EtherCAT and CANopen are used to improve the response speed and data transmission efficiency of the control system and ensure the synchronization of instructions among multiple servo valves.
Fourth, the application case analysis
In offset press or multi-color printing unit, synchronous servo valve is often used to control the phase of each color group cylinder. For example, a high-speed rotary printing machine adopts a distributed servo valve control system, and the central controller coordinates the start, stop and speed adjustment of each color group to ensure the accurate overprint of each color on the paper. Practice has proved that the system can control the synchronization error within micron level, and significantly improve the printing
accuracy and stability.
V. Conclusion
With the development of printing machinery towards high speed and intelligence, high precision control based on synchronous servo valve has become one of the core technologies of printing equipment. Through advanced control algorithm, closed-loop feedback mechanism and high-speed communication technology, printing machinery can realize multi-axis high-precision synchronous operation, thus ensuring printing quality and improving production efficiency. In the future, with the integration of artificial intelligence and Internet of Things technology, the control mode of synchronous servo valve will be more intelligent and flexible, which will bring greater development space for the printing industry.