In the modern industrial automation system, the servo valve coordinated control technology is widely used in occasions that need high precision, high response and synchronous control, such as CNC machine tools, robots, aerospace, heavy machinery and so on. As the core component of hydraulic servo system, the cooperative working ability of servo valve directly affects the dynamic performance and control accuracy of the system. Therefore, how to realize the synchronous operation of multiple servo valves through coordinated control has become one of the key technologies in the design of hydraulic control system.
First, the basic principle of coordinated control of servo valve
Servo valve is a high-precision control valve which can accurately control the flow and direction of hydraulic oil according to the input signal. In a multi-actuator system, if each actuator needs to move synchronously, it is necessary to coordinate the control of each servo valve to ensure that the speed, position or force output of each actuator are consistent.
The core of coordinated control is to establish a unified control strategy and feedback mechanism, so that multiple servo valves can act under a unified control signal, thus achieving synchronization among actuators. Common control strategies include master-slave control, cross-coupling control and synchronous error feedback control.
Second, the main methods to realize the synchronization of servo valves
1. Master-slave control method
Master-slave control is a common synchronous control strategy. Among them, one servo valve is used as the “master controller” to provide the reference trajectory, and the other servo valves are used as “slave controllers” to follow the actions of the master controller. Through the command signal sent by the master controller, other slave controllers adjust according to the deviation, thus realizing synchronization.
2. Cross-coupling control method
Cross-coupling control is to introduce mutual error feedback between controllers, so that each servo valve not only responds to its own deviation, but also is affected by the state of other controllers. This method can effectively reduce the synchronization error and improve the response speed and synchronization accuracy of the system.
3. Centralized control based on PLC or motion controller
In modern industrial systems, programmable logic controller (PLC) or special motion controller is often used to coordinate the actions of multiple servo valves. Through high-speed communication bus (such as EtherCAT, CANopen, etc.), the control instructions are sent to each servo valve at the same time, and the feedback signals of each axis are collected in real time for closed-loop control to ensure synchronization performance.
4. PID combined with advanced control algorithm
Although the traditional PID control is widely used in servo valve control, it is often difficult to meet the requirements of high precision synchronization in multi-axis coordinated control. Therefore, PID control is often combined with advanced algorithms such as fuzzy control and adaptive control to improve the robustness and anti-interference ability of the system.
Third, the key factors to realize synchronous control
-Sensor accuracy and feedback frequency: High-precision position and speed sensors and high-frequency feedback acquisition are prerequisites for accurate synchronization.
-Response speed of control system: Fast controller and communication system can shorten response time and improve synchronization performance.
-Stiffness and consistency of mechanical structure: Stiffness, clearance and friction of mechanical system will also affect the actual synchronization effect, which needs to be optimized in the hardware design stage.
-Optimization of control algorithm: Reasonable design of control algorithm can effectively restrain error accumulation and improve the synchronization stability of the whole system.
IV. Conclusion
The coordinated control and synchronous operation of servo valves is the key to realize the high performance operation of complex industrial automation systems. Through reasonable control strategy, high-precision sensor feedback, fast communication system and advanced control algorithm, the problems in multi-axis synchronous control can be effectively solved, and the stability, accuracy and reliability of the system can be improved. With the development of intelligent control and industrial Internet of Things technology, the future servo valve coordinated control system will be more intelligent and networked, which will bring broader application prospects for industrial automation.