Research On Optimization And Control Method Of Hydraulic System For Large Gantry Shearing Machine

With the development of China in recent decades,a large amount of “social scrap steel” has appeared in China.Under the strategy of vigorously promoting clean production and actively promoting circular economy in the country,how to quickly recycle “social scrap steel” becomes an urgent problem to be solved.The shearing machine is an ideal equipment for scrap steel processed and recycled.It plays an important role in the scrap steel recycled process.However,the shearing frequency of the existed shearing machine is lower,which cannot meet the requirements of rapidly processing of scrap steel.Based on the hydraulic system of Huahong 800 t gantry shearing machine,this paper designed a high pressure and large flow hydraulic system of 1000 t gantry shearing machine to improve the shearing frequency of the shearing machine.Firstly,in this paper,according to the existing structure of the gantry shears,ABAQUS is used to model and simulate the influence of scrap steel with different void ratio on the counterforce of shearing tool during sheared process.The relationship between the void ratio and the counterforce received by the shearing tool and the change curves of stress and strain in the fracture zone of scrap steel with different void ratio are obtained.According to the conclusion,the motion control strategy of shearing hydraulic cylinder is proposed.Secondly,on the basis of the existing hydraulic system to design a new high pressure and large flow hydraulic system,the new hydraulic system adopts multi-pump coupling method,In the outlet of hydraulic pump,pressure loading valve composed of cartridge valve,reversing valve,overflow valve and check valve is employed to improve the inlet pressure of hydraulic system and save pressure loading time,In the hydraulic system where the large flow through all the use of 80 diameter cartridge valve,in order to reduce oil pressure loss and meet the maximum flow requirements;AMESim software was used to simulate and analyze the dynamic characteristics of the 80-diameter cartridge valve and the hydraulic system of the shearing circuit,and compare the simulation results of the shear circuit hydraulic system with the shear results of the original shear circuit hydraulic system.Finally,in terms of control,the fuzzy control theory is introduced in this paper.The fuzzy controller in the control system of gantry shears is designed and fuzzy rules are edited;The fuzzy controller system,conventional PID control system and fuzzy PID control system are simulated by MATLAB Simulink module,the corresponding conclusions are obtained by comparing the simulation results of three control systems.The results show that the shearing time of shearing circuit of the newly designed high pressure and large flow hydraulic system is 8.1s,which is 22.1% lower than the original 10.4s,the overall operating time of the hydraulic system of the shearing machine is 14.8s,which satisfies the requirement of increasing the shearing frequency of the shearing machine.There are 73 figures,11 tables,and 89 references in this paper.