Research and Development of Control System for Ultra Fast Laser Numerical Control Machine Tool

Author:Liu Fei

Supervisor:lin zuo shi shu zuo


Degree Year:2019





Laser processing has been widely used in automobile,electronics,electrical appliances,aviation,metallurgy,machinery manufacturing and other important sectors of national economy.It plays an increasingly important role in improving product quality,labor productivity,automation,pollution-free and reducing material consumption.Combined with the major national project,the research on the laser NC machine tool for micro-hole forming of aircraft engine blade and other key parts such as picosecond and femtosecond laser without recasting layer has been carried out.The control system is developed to realize the collaboration of laser processing equipment,testing equipment and CNC system.Based on this,the following aspects has been studied.In view of the control requirements of laser numerical control machine tools,the system architecture has been developed.The control tasks are divided into different control modules according to the control functions,and a master controller is used to realize the coordinated control of each module.Aiming at the problem of non-linear error caused by rotation axis motion in five-axis linkage,high-speed smooth motion control of five-axis linkage is realized by developing real-time interpolation technology for five-axis machining.In order to ensure the coordination and orderly operation of tasks with different priorities,real-time requirements and communication protocols,the reliable communication technology among the modules of the system is studied.Research on ultra-fast laser processing technology is carried out,and combined with the above technological requirements,special system functional modules are developed to meet the requirements of ultra-fast laser processing for aeronautical work pieces.Through the research of the above contents,this topic has solved some key technical problems of domestic CNC system used in aeronautical work piece processing,among which the main innovations include:The architecture of software and hardware based on layered network is proposed.The layered network scheme can ensure that the whole control structure will be clearer,which is convenient for later design and development.In this scheme,the control tasks are divided into different control modules according to the control functions,and a master controller is used to realize the coordinated control among the modules.The whole control system is composed of a tree structure from top to bottom.It is suitable for the control requirements of laser numerical control machine tools and the strong specialty of laser numerical control machine tools.The trajectory smoothing by adding transitional motion segment at corner is proposed.Spatial arc is used to realize trajectory transition between program segments,which ensures the C1 continuity of trajectory.It has the characteristics of simple calculation and mature technology.In the aspect of improving corner speed,real-time forward-looking technology is used to achieve smooth and high-speed trajectory motion effect.The strategy of smoothing motion control of rotating axis is proposed.The strategy interpolates the cutter axis vector and determines the linear interpolation range according to the allowable error parameters.The maximum velocity is restrained according to the linear interpolation stroke and the performance parameters of the rotating axis.Finally,the vector interpolation segment and the linear interpolation segment are smoothly connected by cubic spline.An improved motion control algorithm is proposed to deal with singularities,which overcomes the deficiency of motion redundancy in the original algorithm.System information exchange based on middleware is adopted.In order to ensure the coordinated and orderly operation of each priority,real-time requirement and different tasks of communication protocol has been used,to solve the compatibility problem of module communication supporting different communication protocols,and to provide a unified API function interface for upper application development,so as to shield the specific implementation details of the system.For the technical characteristics of ultra-fast laser processing,the development and design of system process software are carried out to solve the bottleneck problem that restricts the development of the system,filling the technical gap with the domestic CNC system,and help to improve the overall level of manufacturing industry.Finally,the typical machining processes such as fuel injection rod hole and hollow turbine blade film hole are taken as examples to verify the developed control system.