On Motion Optimization And Punching Strategy Of U-shaped Longitudinal Beam Ventral Punching Production Line

There are 200-500 holes distributed on the ventral surface of the U-shaped longitudinal beam of commercial vehicles.At present,the punching production process and equipment with hydraulic press as the punching press are widely used.For the punching process of the ventral surface of the U-shaped longitudinal beam,it is of great value for the actual production of the production line to complete the processing of all the ventral holes of the longitudinal beam efficiently and smoothly.In this paper,the motion optimization and punching strategy research are carried out on the whole die frame in-line U-shaped longitudinal beam ventral punching production line.The research work is mainly carried out in the following two aspects: First,the acceleration and deceleration control algorithm are used to plan the movement of the moving press to ensure the smooth and efficient movement of the press.Second,based on the processing mode and punching sequence,the punching strategy of the longitudinal beam ventral punching production line is optimized to improve the punching efficiency of the production line.The main research contents and conclusions are as follows.(1)Longitudinal beam ventral punching production line analysis and die frame structure design.In order to comprehensively analyze the through-holes on the ventral surface of the Ushaped longitudinal beam,the diameter and number of the ventral holes of the longitudinal beam are counted and analyzed,and the laws of the diameter,number and distribution of the ventral holes of the longitudinal beam are obtained.In order to clarify the processing flow of the single press longitudinal beam ventral punching production line and the double press longitudinal beam ventral punching production line,according to the processing principle of the production line,the processing flow chart of the two types of production lines is drawn.Based on the analysis of the web face of the longitudinal beam and the analysis of the web punching production line,combined with the number and distribution characteristics of the dies on the overall die frame,the die layout design of the overall die frame of the two production lines was completed,and a reasonable profile of the longitudinal beam punching die was drawn.(2)Simulation and optimization of mobile fuselage motion control.Aiming at the servo motor-ball screw transmission system adopted by the mobile host of the ventral punching production line,the structure diagram of the servo motor-ball screw transmission system is established.In order to meet the motion characteristics of multi-frequency and small displacement of punching main engine heavy press,a new S-type acceleration and deceleration algorithm based on cubic polynomial fitting is proposed.The algorithm has the advantages of smooth acceleration curve and simple calculation.According to the motion control system of the production line,the simulation model of the transmission system is established in Simulink simulation software.The proposed new acceleration and deceleration algorithm based on cubic polynomial fitting is compared with the trapezoidal acceleration and deceleration algorithm,the five-stage S-type acceleration and deceleration algorithm and the modified trigonometric function acceleration and deceleration algorithm.These four acceleration and deceleration algorithms are used as speed inputs for simulation comparison.It is concluded that the algorithm is more suitable for the small stroke and multi-frequency motion control of the heavy press.The superiority of the proposed acceleration and deceleration algorithm is verified,and the motion law of the transmission system is obtained.(3)Punching strategy of single press longitudinal beam ventral punching production line.In order to carry out the research on the punching strategy of the single press longitudinal beam ventral punching production line,through the completion of the setting of the coordinate system,the establishment of the database,the punching partition and matching,and the judgment of the punching sequence,the punching sequence of the longitudinal beam that meets the actual processing is obtained.In order to reduce the punching time of the single-press longitudinal beam ventral punching production line and improve the punching efficiency of the production line,a double punching mode and a punching sequence solution method based on the modified ant colony algorithm are proposed from the aspects of punching mode and punching sequence.Through case analysis,the proposed punching strategy significantly improves the punching efficiency of the single-press longitudinal beam ventral punching production line.(4)Punching strategy of press longitudinal beam ventral punching production line.The punching strategy research is carried out for the double-press longitudinal beam ventral punching production line.The punching strategy of the single-press longitudinal beam ventral punching production line is similar to the coordinate system setting,database establishment,punching partition and matching,and punching judgment.Based on the situation that the double press can be processed at the same time,a solution method for the comprehensive punching sequence is proposed,and the punching strategy of the double press longitudinal beam ventral punching production line is obtained.In order to further improve the punching efficiency of the double press longitudinal beam ventral punching production line,the influence of the press partition on the punching efficiency of the production line is explored.Through the example analysis,the optimal press partition under the longitudinal beam example is obtained.