Three Dimensional Stretch Bending Process Control Based On The Rule Of The Arm Type Stretch Bending Machine

With the rapid development of high-speed rail field,the production needs of high-speed rail vehicle itself gradually increased.Used in the manufacture of high-speed rail vehicle's head and body are skin and beam,which are made by stretch bending of the arm pull bending machine.In process control of stretch bending forming of the arm pull bending machine,tensile force size and bending degree,rebound amount,pull bending step speed of Profile are very important process parameters,they will directly affect the bending precision of profiles.However,due to many factors such as nonlinearity,uncertainty,mechanical error and control lag,rely on the experience of the operator is difficult to achieve effective control,especially when the conditions change,there will be very easy to fold,broken section,projectile flying wounding and other issues.It will cause a decline in the quality of products,consumption increased.In view of the above situation,the main contents and innovations of this paper are summarized as follows:1.Based on stretch arm stretch bending machine production technology theory,research on stretch shape variables of profile in stretch bending process control.Using the method of “loading track”,the precise stretch bending process control is realized by controlling the running track of each hydraulic cylinder.2.Establishing the physical model of stretch bending machine and using it in the mathematical model of stretch bending process control.The coating angle is calculated by the model,and the relationship curves between coating angle and tensile force are obtained,so initially determine trajectory curve of each hydraulic cylinder.3.Establishing the Load path model of human-computer interaction.Design the editor of Knowledge rule.With the support of production history data,based on actual loading trajectory and the expected trajectory of each hydraulic cylinder,process specialist adjustment and validation.Knowledge rules are generated by knowledge editor and knowledge rule base are generated.4.Combining with the actual situation of stretch bending production,compilingthe design document of software system of stretch bending process control and use C++ programming to achieve the software system.Based on the control demand in the production of arm pull bending machine,upgrading the original manual single cylinder operation to automatic process control for 3D space and four axislinkage.The four axis linkage Includes rotary arm cylinder,stretching cylinder,lifting cylinder and rotary cylinder.In the feedback of actual production of profile by stretch bending forming,the stretch bending process can achieve complete automatic control.The formed profile's surface is smooth and the bending precision meets the technological requirements.The feasibility and accuracy of the bending process control system are verified.The stretch bending trajectories of four axis linkage are clear and intuitive.The stretch bending process control system has been put into production.