The hydraulic cylinder is an executive element in the hydraulic equipment system. It is an energy conversion device that converts the pressure energy of the liquid into mechanical energy to achieve reciprocating motion. The hydraulic cylinder uses a simple and reliable structure to efficiently realize linear motion within a large thrust range, thereby significantly expanding the application range of hydraulic transmission.
The stability and reliability of the hydraulic press equipment system has become a very prominent problem. In addition to the reliability design of the hydraulic system, the fault monitoring and diagnosis technology of the hydraulic system has attracted more and more attention and has become an important direction for the development of hydraulic technology.
With the continuous development of modern large-scale production and the continuous progress of science and technology, in order to maximize production efficiency and hydraulic press quality, hydraulic press equipment as the main production tool is developing in the direction of large-scale, high-speed, precise, continuous operation and complex structure. . In this way, while meeting the production requirements, the potential and ways of equipment failure are correspondingly increased; and once the equipment fails, it may cause serious or even catastrophic consequences. How to ensure the safe and normal operation of hydraulic press equipment has become a major issue in modern equipment operation, maintenance and management. Online monitoring of mechanical equipment is an important measure to ensure its safe, stable, long-term, full-load, high-performance, high-precision, and low-cost operation.
The so-called online monitoring (On-line Monitoring) refers to the entire process of signal collection, analysis, diagnosis, display, alarm, and protective treatment of the operating process and status of hydraulic equipment on the production line.
The online monitoring technology of hydraulic press equipment is based on the modern scientific theory of system theory, cybernetics, reliability theory, failure theory, information theory, etc., and uses instrumentation equipment including sensors, computers, and artificial intelligence as technical means, and comprehensive considerations The special laws and objective requirements of each object, so it has the characteristics of advanced, applicable, complex and comprehensive modern scientific and technological systems.
At present, the main trends in the development of online monitoring technology are as follows.
① The whole system develops towards high reliability, intelligence, openness and integration with equipment, from simple monitoring, analysis and diagnosis to active control.
②The collector develops in the direction of high precision, high speed, high integration and multiple channels.
③The sampling method develops from isochronous sampling to isochronous synchronous full-period sampling to obtain a variety of information including phase; the collected data has evolved from only steady-state data to a variety of data including transient data.
④The number of channels develops from single channel to multi-channel, and the signal type develops from a single type to multiple types (including speed, vibration, displacement, temperature, pressure, flow, speed, switch value, acceleration, etc.).
⑤Data transmission develops from serial port and parallel port communication to network communication.
⑥The monitoring system is developing in a user-friendly direction, with intuitive display and convenient operation, and adopts multimedia technology to realize large-screen dynamic three-dimensional display.
⑦The analysis system develops in the direction of multi-function, which can analyze not only a single set of data, but also multiple sets of data such as on and off.
⑧Diagnostic system develops towards intelligent diagnosis of multiple faults, from online collection and offline diagnosis to online collection and real-time diagnosis.
⑨Data storage is developing in the direction of large capacity, and storage methods are developing in the direction of general large-scale databases.
⑩Diagnosis and monitoring methods are developing towards remote diagnosis and monitoring based on Internet/Intranet. Remote diagnosis and monitoring also include systems based on wireless networks.
