Research On Control Algorithm Of Electro-hydraulic Proportional Valve Control Four-cylinder Synchronization

Hydraulic synchronous control systems are widely used in mechanical equipment,such as hydraulic cranes,straightening machines,forging hydraulic machines or large cranes,serving the national economic construction and manufacturing industries.The four-cylinder synchronous control system is a complex electro-hydraulic-coupling system.The system characteristics are not only required to meet the rapidity,accuracy and stability,but also the synchronous rectification ability is very important.It also meets the requirements of the general electro-hydraulic proportional system.High synchronization accuracy requirements.In this paper,the electro-hydraulic proportional valve-controlled four-cylinder synchronous control system is taken as the research target,and the main contents of the four-cylinder synchronous system control principle,synchronous control strategy and control algorithm are studied.First,the three components of the four-cylinder synchronous test bench are analyzed: hydraulic components,electronic control components and detection components.According to the design requirements of the system,the main hydraulic circuit of the synchronous system is designed,and the reasons for the system's unsynchronization are analyzed.Secondly,since the coupling of the signals of each channel of the multi-cylinder synchronous control system is more complicated than that of the single electro-hydraulic proportional valve-controlled cylinder,the control strategy deviation coupling and adjacent cross-coupling commonly used in the multi-cylinder synchronous system are analyzed.In order to simplify the control model,it is necessary to simplify the control model.Therefore,the concept of adjacent cross-coupling error is introduced to improve the adjacent cross-coupling control strategy.The improved control strategy simplifies the control structure and has strict convergence,which is more suitable for the application of engineering actual systems.Finally,the control algorithm of the four-cylinder synchronous control system is analyzed,and according to the characteristics of the electro-hydraulic proportional valve-controlled cylinder,the sliding mode variable structure control is selected.Sliding mode variable structure control is invariant to the parameter perturbation and disturbance of the controlled object system,but the sliding mode variable structure control is essentially discontinuous switching control,which will cause chattering problem.Therefore,a control algorithm combining sliding mode variable structure and fuzzy control is proposed.The nonlinear fuzzy sliding mode control algorithm is adopted to weaken the chattering to improve the control precision.For the electro-hydraulic proportional valve-controlled four-cylinder synchronous control system,the hydraulic system model was established in AMESim,and the control model was established in Simulink for joint simulation.The results show that compared with the traditional integral fuzzy sliding mode control algorithm,the nonlinear fuzzy sliding mode control algorithm uses the nonlinear fuzzy sliding mode control algorithm to achieve faster response,smaller system chattering and higher synchronization accuracy.The improved adjacent cross-coupling control strategy is compared with the parallel control strategy.The simulation results show that the improved adjacent cross-coupling control strategy system synchronization error will also be reduced and the adjustment time will be shortened.The effectiveness of the improved adjacent cross-coupling control strategy and the nonlinear fuzzy sliding mode control algorithm for the control of the electro-hydraulic four-cylinder synchronous system is verified.