Utomatic Control System Of Variable Polar Plasmaarc Welding Based On Ethercat Fieldbus

With the development of information technology,computer technology and application of automatic control technology,the traditional welding face is completely changingthe welding process of automation has become an urgent need,it can not only greatly improve the welding productivity,more importantly,Quality,improve the operating environment.The most basic problem of welding automation is the application of automatic welding machine and welding machinery and equipment to form a welding automation system,through the automatic control of welding procedures to complete the automatic welding of the workpiece.Therefore,according to the characteristics of welding parts and welding quality requirements,to build a reasonable welding automation system is to achieve the premise of welding automation.Fieldbus control system as a new generation of control system,with its architecture open,flexible and convenient system integration,intelligent hardware,digital transmission,control the characteristics of high-quality control is to replace the traditional automatic control system to become the mainstream of automatic control system.Based on the variable polarity plasma arc welding,the EtherCAT field bus is used as the communication network of the control system,and the hardware platform based on the embedded industrial PC and the Beckhoff E-bus module is used to build a set of flexible polarity based on the EtherCAT field bus Plasma arc welding automation control system.By establishing the mathematical model of the Cartesian and the positioner,the kinematics analysis is carried out to read the running G code to realize the trajectory of the complex curve of the welding torch.System master PC and welding power to EtherCAT protocol as a communication protocol for data exchange,in the welding process to achieve the welding power from the arc from the main arc and other welding timing control and welding process parameters of the given and monitoring.Using the open software development platform CoDeSys design system program,developed a friendly human-computer interaction interface.According to the mathematical model established in the second chapter to prepare the movement program,the development of teaching procedures,through teaching to generate G code file,using CoDeSys SoftMotion component CNC function to read and analyze the G code file,in the positioning machine for the tablecoordinates The virtual axis interpolation program is implemented in the system,and the real axis motion of the Cartesian coordinate robot is realized by kinematic transformation,which leads to the complex space trajectory walking in the workpiece coordinate system of the locating machine participating in the movement.In order to ensure the welding path and the welding process parameters and the good match,developed for the variable polarity plasma arc welding process of teaching process,to achieve a good combination of motion control and welding process control.Experiments show that the automatic control system based on EtherCAT bus can complete the motion control function and VPPA welding power system control function.The motion control precision and data transmission can meet the requirements of automatic welding,and basically realize the purpose of automatic welding control.