Research Of Seam Tracking System For Laser Brazing Based On Fuzzy PID

With the wide application of laser welding in automobile manufacturing,laser brazing has become the mainstream technology of the welding of car roof,and welding quality directly affects the safety and stability of automobile.As an important means to improve welding quality,seam tracking has gradually become a research hotspot in this field.Aiming at the problems of existing seam tracking,a laser brazing seam tracking control system based on Fuzzy PID is designed to improve the welding quality of car roof.The specific research contents are as follows:Firstly,the laser brazing process of car roof is introduced,and the performance index and control requirements of laser brazing seam tracking control system are analyzed.According to the process characteristics of laser brazing,the measurement system scheme is determined,the actual deviation is judged by the force of welding wire.Secondly,the principle of laser brazing seam tracking is analyzed,and the control model of laser brazing seam tracking is established.Then the seam tracking control algorithm is realized.Based on the seam tracking control model of laser brazing,combined with the characteristics of PID algorithm and fuzzy control,a fuzzy PID controller for seam tracking is designed.With the aid of MATLAB,the fuzzy PID controller is offline,and the seam tracking algorithm based on Fuzzy PID is realized on STM32,The important link of realizing weld seam tracking function is completed.Then the software of laser brazing seam tracking control system is completed.In order to meet the communication requirements of the control system,CANopen master station is implemented on STM32;the welding seam tracking algorithm can directly control the motor to adjust the position of the welding torch through CANopen bus;according to the laser brazing process,the upper computer control software of the welding seam tracking system is developed to realize the necessary control process in the welding process.Finally,in order to verify the performance of laser brazing seam tracking algorithm and control system,combined with the actual conditions,the laser brazing simulation experiments for straight and curve welds are designed.The experimental results show that the laser brazing seam tracking system can adjust the welding error in real time and meet the design requirements.