The Control And Research Of Automobile Axle Hydraulic Pressing System

Automobile axle housing inflation pressure forming process is an emerging technology. Compared with the traditional casting and stamping and welding, it has advantages of light quality and good performance. The process is carried out by hydroforming the reduced diameter tube to get preformed tube, and finally pressing the preformed tube to get axle housing prototype. The movements of hydraulic press, with large inertia and nonlinear characteristics, have a significant impact on the position of the axis of the tube, and thus affecting the sealing effect at both ends of the tube. This paper focuses on how to make the central axis of the tube remain in the vicinity of the initial position.First, components and working processes of the hydraulic press of inflation pressure forming automobile axle are introduced briefly. According to the hydraulic press work requirements, the main hydraulic control circuits are designed, and the action sequence of various control elements are elaborated. The selection and calculation of key components also are carried out in line with the proposed technical indicators.Secondly, the models of cartridge direction valve, cartridge relief valve and cartridge proportional throttle valve are established by AMESim. Through continuous debugging the static and dynamic simulation, and comparing with the sample curves, rationality of the system model is verified. For hydraulic system control accuracy requirements, the method of using NLPLQ algorithm to optimize PID controller parameters is proposed, which not only saves conventional tuning time-consuming, but also achieves good control effect.Finally, the system co-simulation model is set up, and the transfer function of long and short stroke cylinder are identified by giving a step signal. On this basis, the dalin controller of pure delay system is designed and replaces the PID controller of the original system. The results show that almost two-cylinder displacement error can achieve the same control result, which also indirectly reflects the reliability of the identification...