Research Into Control System Of Hydraulic Deep Drawing Press Based On Limit Deep Drawing Principle

The thoroughgoing theoretical analysis and the experimental study aimed at the control system of high speed, intelligent controlled hydraulic deep drawing press are carried on in this thesis. Based on the limited drawing technical theory, a way of deep drawing with changeable moving speed and Blank-Holding Force (BHF) is put forward, which improves the traditional mode of drawing with fixed BHF. The control performance is enhanced and the technical content is increased after adopting the intelligent controlling method used in the monitoring and control software, which especially developed for the hydraulic press system. Following substance is included.First, the limited drawing technical theory used in deep drawing with changeable moving speed and BHF is put forward. Based on the study of deep drawing press' development in the civil and abroad and the distorting theoretical analysis of metal plate, a new technique, that is the way of deep drawing with changeable moving speed and BHF, is put forward. The forming limit can be enhanced and the application can be widely extended by use of this new kind technique. The influence of some important technical parameters such as speed and BHF on deep drawing distortion is also analyzed.Second, the PID control and fuzzy control method are respectively applied into the BHF control of the hydraulic press. The contrasts to step respond between PID control method and fuzzy control method are studied. The given signs can be precisely followed when PID control method acts, however, the system dynamic performance can be further improved when fuzzy control method has effect. In the meantime, the explorative study of neural network adaptive control system is carried on.Finally, the experiments on stainless steel cylinder with flange plate work-piece drawing are made. Under the ultra-low drawing coefficient (m=0.5) drawing conditions, the experimental conclusion shows that the BHF control, which reduce from high pressure to low pressure then rises to medium pressure, are more beneficial to reduce the drawing coefficient than the old drawing mode with fixed BHF control. Meanwhile, the surface quality of the work-piece can be improved and the ratio of cracking in the course of drawing can be cut down.The monitoring and control system with IPC is developed, which provides ample condition for automation and intelligence of the hydraulic press and creates a more convenient and easily operating test environment.