Research On Non - Impact Control Strategy And Energy Saving Optimization Of 50MN Full Hydraulic Press

Flattening machine is an important device for the wide heavy plate mill’s subsequent finishing, which is used to assist repairing the plate’s problems of bending, buckling and warping. By analyzing the production process of 50 MN full hydraulic press flattening machine in the Shagang 5000 mm hot rolling production line, this thesis found some serious shortages lie in the electromagnetic valve hydraulic press flattening machine. 1. The flattening machine head and plate will have mechanical impact if the speed of head presses is too quickly. If the head’s fast/slow and drop condition directly changed or the working pressure directly constructed will lead to pressure oscillation in the working cylinder. 2. The largest flow needs of flattening machine system is 520L/min, while the operation scope of auxiliaries needs are 46~136L/min. Therefore, if the high pressure pump constantly provides flow of 520L/min for auxiliaries’ action cylinder will cause the extra overflow and hot, which will result in energy waste.First, by studying the coupling and cross relationship and working mechanism of 50 MN flattening machine’s electro-mechanical and hydraulic integrated system, this thesis tries to build the distributed electric control architecture of PLC300+ET200M.Second, to the impact and shock problems caused by hydraulic press flattening machine’s work which controlled by electromagnetic valve, this thesis tries to segment flattening machine head and press and regard the proportional electromagnetic valves as the hydraulic control valves. And in the stage of pressure, a mathematical model between the press quantity and load pressure was built so as to construct a non-impact control strategy based on the location/pressure double-closed loop head control system. To make the head contact the to be repaired steel plate without impact after the fast、slow speed coordination in the stage of empty travel press. And after contacting the steel plate, to build working pressure gradually to maximally moderate the pressure shock of the action cylinder.In addition, to the energy waste problem caused by the mismatch of flow supply and demand when do the auxiliaries action, this thesis tries to adopt Rexroth VT5035 amplifying board closed-loop to control A4 VSO variable displacement pump’s swash plate angle, and use the variable displacement pump’s displacement Vg’s controllability to make proportional pump supply flow according to needs. Besides, we can use the way of variable displacement pump plus fixed displacement pump as an energy source, and build flow matching pump-control strategy. That is to say, proportional pump supply flow according to needs online. While the flattening machine’s head and press work, proportional pump in the full-flow condition loads simultaneously with fixed displacement pump to reduce the flow redundant caused by auxiliaries actions.Last, based on the theory of this paper to do a field debugging of Shagang 50 MN flattening machine, and by contrasting the production data before and after optimize, we find the displacement curve of flattening machine head and press is over smooth, and the pressure fluctuation in the actuator reduces 52%. Besides, the flow redundant caused by auxiliaries actions reduces 68%.