Research On Intelligent Lubrication System Of CNC

With the development of modern CNC machine tools,the precision and reliability requirements of moving parts such as guide rails have been further enhanced,and the lubrication system of CNC machine tools has become more important and complicated.From early manual oil or grease supply,to subsequent mechanization and automated supply,all rely on human experience or pre-set parameters for lubrication.Load changes and sudden failures require timely human intervention and adjustment.It is difficult to keep the lubrication state always good,it is easy to cause excessive wear of moving parts of the machine tool,and it is easy to cause waste of lubricating oil.Based on the theoretical research,and based on the fuzzy control method,this paper establishes an intelligent lubrication system,which can monitor the lubrication points separately and supply oil on demand to improve the reliability of lubrication and the utilization rate of lubricating oil.This article will be divided into six chapters to study and introduce the topic.First of all,we studied the relevant literature results,analyzed the development background of CNC machine tool lubrication system and the research status of machine tool lubrication in China and abroad,and clarified the research objectives and key difficulties of this topic.Then the friction mechanism and heat transfer mechanism of the rolling linear guide pair of the machine tool are studied in detail.Using the elastohydrodynamic lubrication theory,the total friction force at the contact interface between the guide rail and the sliding block was analyzed and calculated,and the influence of speed and oil supply on the friction force was analyzed.Through appropriate assumptions and simplifications,a heat transfer model that can be solved is established,and the heat exchange boundary conditions of the slider are analyzed.Then we use the numerical calculation method to obtain the temperature variation rules of the specific position of the slider under certain conditions,and then use the above rules,and the temperature change information of the temperature measurement point to establish BP neural network to solve the temperature value of the friction contact interface.This article describes in detail how to use the Solidworks simulation tool for heat transfer analysis and how to build BP neural network using software.Then the hydraulic schematic of oil supply system of the CNC,along with the controller hardware used in the intelligent lubrication system and the implementation of the fuzzy control algorithm are introduced.This article uses NI's myRIO-1900 controller,which is programmed using the LabVIEW language.The board has a rich IO interface and powerful secondary development performance,and the fuzzy logic toolkit included with LabVIEW software can easily implement fuzzy control.The fuzzy variables,membership functions and fuzzy control rules tables of fuzzy controllers are given.This paper also builds an intelligent lubrication system simulation test platform,introduces the composition and selection basis of the two-degreeof-freedom sliding table.The oil supply system of the platform is provided with a valve block between the oil pump and each lubrication branch.Under the command of the controller,oil can be supplied to each branch separately and with frequency conversion,real-time monitoring,intelligent control and active lubrication of each point is realized.The feasibility of the idea was verified by the control experiment of the test platform under high,medium and low speed and light load and heavy load operation conditions,which provided a data foundation for subsequent experiments on real CNC machine tools.Finally,this paper summarizes the research done,analyzes the existing shortcomings and forecasts the future improvement work.