Adaptive system for automatic control of the fine drawing process

Abstract

The paper considers the technological process of deep drawing, taking into account the high degree of deformation of the metal and the small thickness (0.5 mm) of the workpiece. Given the high complexity of the process and the impossibility of its representation in an analytical form, the paper uses its representation in the form of a phase portrait in the plane of the drawing force and movement of the hydraulic press punch. Phase trajectories in the mentioned plane determine the geometric dimensions of the product, characterize stresses and deformations during the process and determines the structure of the process control algorithm. The digital positional tracking system considered in the work includes electromechanical, hydraulic, pneumoelectric and electronic links. The system provides precision positioning of the hydraulic press punch with control and control of its movement speed. The paper provides an ideal mathematical model of the extraction process. As a result of comparing the phase trajectories of the model and the real process, a possible difference is revealed due to the interference in the real process. The resulting difference makes it possible to form an additional control effect on the punch speed control circuit in the system in order to compensate for the resulting misalignment. Thus, the stabilization of the drawing force in the function of the movement of the punch is realized. The paper provides mathematical descriptions of all parts of the system, provides dynamic characteristics of the process. As disturbing effects on the drawing process, the following are considered: metal hardening, the unstable friction force that occurs when the workpiece is pressed, the change in the drawing force when the parts of the workpiece are drawn into the matrix, corrugation, metal thinning during the transition of the bottom part to the side wall of the product. The mentioned disturbances without the system in question did not fully ensure the quality of the products. As a result of the resulting marriage, significant production costs took place. The materials of the work and numerical data of the links of the technological process system were obtained by the example of manufacturing a cylinder of an OP-2(3)-ABCE powder fire extinguisher produced at the ZPO plant Itself (fire fighting equipment plant).