Design And Research Of The Mechanical And Control System Of Curved Edge Seam Equipment

At present,the production enterprises of automobile floor mats all use manual operation sewing machines for production,which not only has high labor intensity and low efficiency,but also has unstable product quality.There is an urgent need to develop automatic automobile floor mat sewing equipment.In this project,we cooperated with enterprises to develop a special automatic sewing machine for car floor mat products,which is an automatic overlock sewing machine with curved edges.This thesis mainly studies from the following aspects.(1)Analyze the movement process of car mats when they are overlocked.By analyzing the existing curved edge sewing program and pointing out its shortcomings when it is used in the sewing of automobile foot pads,a 2DOF feeding motion scheme with the instant center of speed as the rotation center is proposed,and the motion parameters of the material contour size are calculated.(2)According to the determined motion scheme and the overall structure of the curved seam equipment,based on the Solid Works 3D modeling software,the structural design of each unit of the curved seam equipment was completed,and a test prototype for testing the feasibility of the motion scheme was actually manufactured in the enterprise.(3)Analyze the functional requirements of the control system and the logic flow of the curved edge seam equipment.For the prototype of the curved edge seam equipment,the overall scheme of the control system hardware is proposed and the hardware selection;Analyze the control logic flow of the host computer,design the overall program of the host computer control system and develop the corresponding control software,write the control program for the interaction between the PLC and the touch screen and the control program for the interaction between the PLC and the host computer.(4)In order to make the car floor mat sewing equipment suitable for different twodimensional shapes and sizes,a method for automatically generating the parameters of the feeding motion control program based on the CAD two-dimensional graphic file of the floor mat is proposed.Use C#language to design the host computer software,realize DXF file analysis,calculate motion parameters and other functions,and transfer the parameters to the PLC designated register through Modbus communication protocol.A method for judging arc concavity and convexity is proposed and converted into C#program code.The test of two different shapes of car mat graphics examples shows that the 2DOF feeding motion scheme and the host computer software can be used for flat car floor mats of different shapes composed of straight lines and curves,and are universal.