| The press mode of full-hydraulic leveler used in mid-thick plate is different from that of traditional leveler. Full-hydraulic driving is applied to the full-hydraulic leveler, which has a lot of characters, such as high control accuracy, high automation and heavy output force. With the higher performance requirements in mid-thick plate, such as high-strength, corrosion-resistant and anti-cracking and so on, production equipment of mid-thick plate are optimized and applied. The full-hydraulic leveler with automatic control and high accuracy control will be the development trend of leveler. The hydraulic press system, which directly decides leveler property, is the core technology of full-hydraulic leveler.The mathematical model of press system of full-hydraulic leveler is built, after the working principle and technical parameters of full-hydraulic leveler are analyzed. The properties of electro-hydraulic position control system and electro-hydraulic control system are analyzed and compared. Aiming at the problem that overload protection doesn’t response in time, a new force switching electro-hydraulic position and force hybrid control system based on the set value is put forward. Combining advantages of fast response and no overshoot in electro-hydraulic position control system and benefits of good stability and high force control precision in electro-hydraulic force control system, the self-protection ability is improved by hybrid control system. Owing to defects of the electro-hydraulic force control system, the controller of auto disturbance rejection control with disturbance feed-forward compensation is built to reduce the influence of disturbance on the straightening, enhance force control accuracy and achieve constant straightening force control. The dynamic performance of control system is analyzed by united simulation of Matlab/Simulink software and AMESim software. Hydraulic system is built by AMESim software and the control system is constructed by Matlab/Simulink software.The actual effect of control system based on the auto disturbance rejection control with disturbance feed-forward compensation is verified by full-hydraulic leveler in laboratory. The research results show that The electro-hydraulic position and force hybrid control system based on the auto disturbance rejection control with disturbance feed-forward compensation not only has faster response speed but also achieves constant force straightening. The control system enhances the ability of overload protection by taking force as controlled volume.The electro-hydraulic position and force hybrid control system of full-hydraulic leveler not only enhances the control precision of straightening force, but also achieves constant force straightening. Meanwhile, the control strategy enhances the ability of over load protection. It will provide theory reference value for other researches on electro hydraulic servo system of heavy load and large equipment. |
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