| Hydraulic press is one of the facilities which are used abroad in the manufacture of product forming. Because of it's aborad applicability in work, hydraulic press are applied abroad in every department of national economy. With the development of the spaceflight project and the requirement of the modern national defence, it calls for higher precision and larger tonnage hydraulic press machine. 300MN hydraulic press machine is the biggest press machine in both our country and Asia, which is the key facility to manufacture kinds of spaceflight equipment and military establishment. However, the operation system of 300MN hydraulic press is ageing, and it is necessary to be redeveloped. In the course of redecvelopment, the structure of "water control water" was replaced by the new structure of "oil control water". The new oil system plays an important role in the operation system of hydraulic press. In order to realize the properties and the effect factors of the system well, the operated hydraulic system of 300MN hydraulic press was studied in this paper. By modeling and simulation with computer, the properties of the system was realized and the new control strategy was analyzed according to the interference of suddenly load. So the study of this dissertation is of great significance to enhance the hydraulic control precision and efficiency in theory and practice.In this paper, according to the real work situation of 300MN hydraulic press, the structure of the operated system was analyzed at first. A new digital electrical-hydraulic system with the core of electrical-hydraulic proportional technologies was designed, which can control the flow precisely with the electrical system, and then finish the control of the whole hydraulic press.The dynamic model of the hydraulic elements are established base on the basic equations, and then these single model are encapsulated, at last by copying and linking of these single models the complex simulation model is obtained. The complex model was used to simulated in computer, and comparing with the experiment result, the model of this system was correct. The simulation result show that the performance of operated hydraulic system without controller can not meet the need of industry, and it must be adjusted by a new controller.According to the interference of suddenly load, a new control strategy was studied in this paper. The PID control and PID—H_∞control was simulated separately, and the result shows that the PID control can not restrain the interference of load and the performance is bad. The PID—H_∞controller which is combined with PID control and H_∞control can ensure the precision of the output tracking and restrain the interference of load well. The simulation result indicated this is a good control strategy for the operated hydraulic system of hydraulic system. |
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