| It is most important of steel industry for the development of industrial manufacture, which provides the raw material for the municipal infrastructure. It is also the basic of the science researching and “Made in China 2025”. The development of steel industry not only can improve the quality of steel production, but also can promote the equipment manufacturing industry developing fast.The shearing technology is the last process in steel rolling, which affects the production quality of the steel plates directly. This paper based on the hydraulic double sides rolling shear designed by Taiyuan University of Science and Technology mainly researches on the hydraulic system of hydraulic rolling shear and its control strategy, which lays the theory foundation of the intelligent production of double sides rolling shear.The movement feature of the double sides rolling shear is analyzed. And the mechanical structure is simplified to a ten rods mechanical structure with 2 DOF in order to do the motion analysis and force analysis. Then, the velocity and accelerated speed of each rod are calculated by the analytic method. Based on the motion analysis, the force analysis of the cylinder has been done.Based on the production practical, this paper develops the hydraulic system for double sides rolling shear, which adds a regulating loop and takes out counterbalance valve. Then, the reliability of the hydraulic system is researched, which verified the safety of the new hydraulic system is enough. The hydraulic system of double sides rolling shear uses unsymmetrical valve to control the unsymmetrical cylinder, which is a typically nonlinear system. In order to research the characteristics of the hydraulic system and design its control strategy, the math model of the hydraulic system is built. At last, do the simulation by AMEsim, and the results indicate that the new hydraulic system can accelerate the response time and make the output force bigger.For the load force of the rolling shear is variational, and the math model of some nonlinearity factors cannot be built accurately, the paper designs the cascade control based on the disturbance observer, which include a position outer loop and a pressure inner loop, and cascaded by a virtual control law. Do the simulation by AMEsim and MATLAB/Simulink, the results show that the cascade control based on the disturbance observer improve the tracking performance of the cylinders and make them move along the given curve.According to the cascade control based on the disturbance observer, the paper further designs the synchronization control strategy to make the four cylinders move harmoniously to achieve the rolling move to cut off the steel plates. Compared to the PID control strategy by simulation, the results indicates that the double sides rolling shear synchronization control strategy can make the four cylinders can move harmoniously and the control precision is higher than that of PID control.The experiments are conducted on a double sides rolling shear with the new hydraulic system and the new control strategy. Compare with the PID control strategy, shear the plates with different thickness, the experiments results show that the new hydraulic system and its control strategy make the double sides rolling shear cut the steel plates easily, the robustness and stability are also improved obviously. It is an innovative technology that meets the production demands enough.The results of this paper put forward a feasible plan for the hydraulic double sides rolling shear, which is benefit for applying on the engineering. It is also significant for applying on the hydraulic servo system with power load and complex working condition. |
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