| The flow characteristics of water bucket is directly determined by theperformance of diversion mechanism in pelton turbine, which has a major impact onthe hydraulic efficeieny and running life. Under the background of subjet SystemDesign of Jet-nozzle for Pelton Turbine conducted by Institute of fluid mechanicsand control center together with Harbin Institute of Large Electric Machinery, thisthesis research on the synchronous control of jet-nozzle in diversion mechanism. Inorder to increase the precision of positon control system and its automation level,Electro-hydraulic servo technology is ever firstly introduced to instead of traditionalmechanical control system. Multi-cylinder displacement synchronization control ofhydraulic system is always a difficult point, based on the purpose of improvingsynchronization characteristics of multi-jet-nozzle system during displacementadjustment, the research draws lessons from the strategy of motor synchronizationcontrol, delivers a thoroughly investigation on the promotion effect of severalcoupling control methods and Model Reference Control Adaptive algorithm onsynchronous control through simulation and tests, meanwhile analyses andcomparisons are made.This paper establishs electric servo system models of pros and cons seperatelytaking the dynaminc characteristics difference of non-symmetric cylinder systeminto account, furthermore, uses Z-transformation and difference equation gaining thediscrete control model of hydraulic servo system. Jet-nozzle displacementadjustment demands quite high location precision, requiring for more excellentcontroller. Genetic algorithm is applied optimizing PID control parameters,improming the performance of every single loop. Transplanting relative couplingcontrol, adjacent cross coupling conrol and ring coupling control which are mainlyused in motor sychronization system to hydraulic servo sychronization controlsystem, measuring the superiors and inferiors through simulation with LabVIEW. Inotder to gain better response effect in accuracy and control stability from step signal,designing the Model Reference Adaptive Controller, by combining coupling controlmethods and MRAC, sychronization permformance of the system gets promoted to acertain extent.Experimental researsh is delivered on hydraulic platform of pelton turbineagainst the jet-nozzle system, verifying the simulation result that coupling controlmethods have great influence on system's synchronization behavior. Comparing andanalysing synchronous characteristics of different control methods,which shows out that model reference adaptive control-adjacent cross coupling controller has theoptimal performance, its step signal response synchronization error reduces to26.7%of the original system, sine signal response synchronization error of differentfrequencies are less than16.7%by contrast of original system, meanwhile, standarddeviation of sychronization error also declines, which means the system's controlstability gets enhanced. Research results show that model reference adaptivecoupling control algorithm dramatically improves system's sychronizationperformance, position accuracy, control stability and other indicators are pomoted tocertain extents, meeting the test requirement, ensuring theprecision ofsychronization control in multi-jet-nozzle displacement adjustment system. |
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