Research On Fuzzy Adaptive Power Control Of Laser Welding Tailor Rolled Blank Plate

Considering the advantages of rapidity,small deformation and convenience,the laser welding has gradually become one of the vital welding procedures in the automotive manufacturing.Meanwhile,the lightweight material tailor rolled blanks used to achieve body weight reduction and ensure the connection strength has become an effective selection for automotive lightweight research and energy-saving emission.However,the change in material thickness and power densities resulted in different penetration of various thicknesses effects the whole welding quality in the process of laser welding for tailor rolled blanks.Penetration as a welding quality evaluation index can be achieved by controlling the welding speed and laser power.Considering that the influence of welding speed on penetration is little,the width of penetration is large and the requirements of the system are high,the laser power is easy to control and the penetration depth is significant.Combining with the project and the demand of weld tracking,the research on real-time power control to improve welding quality is introduced.The full paper develops gradually from engineering problems to practical applications,from easy to difficult and from software and hardware systems,control algorithms to experimental simulation analysis.The main research are as follows:(1)Aiming at the software and hardware requirements of power control and the analysis of input and purpose in the laser welding process of the tailor rolled blanks,the selection of vision sensor coaxially acquiring the information of weld pool pinhole and image acquisition equipment is determined based on the dual control system of the motion controller and the numerical control.Moreover,the analog communication between the laser and the computer is also established to design the hardware composition of each functional module.Combined with hardware equipment,the system architecture and functional requirements are analyzed.Finally,the software and hardware constructions of the power control system are completed.(2)Based on the power control system,the power control experiment of tailor rolled blanks is carried out.According to the dual control system,the open-loop power control based on numerical control and the closed-loop power control based on board card,the through hole area based on threshold segmentation and the penetration state coding classification input based on convolution neural network are proposed.These researches to obtain the power control in the welding process include the linear proportion under the control of variable power control and board card and the design of PID controller and fuzzy controller.(3)The welding experiment and simulation and laser output power measurement experiment are carried out based on the power control system and algorithm design,which achieves the power control of the laser-welded tailor rolled blanks and high welding quality.In addition,the effectiveness of the fuzzy controller and the application value in engineering practice are also verified.