Research On Control System Of Double Hanging Point Hydraulic Hoist Based On Synchronous Drive Technology

In large-scale water conservancy and hydropower projects,hoist plays an important role in river closure and flood discharge.Double Hanging Point Hydraulic Hoist has been widely used because of its advantages of small space occupation,convenient installation,stable driving force and large bearing capacity.In this paper,the Double Hanging Point Hydraulic Hoist is taken as the research object.The synchronous driving technology of the Double Hanging Point Hydraulic Hoist is mainly studied to achieve synchronous control of the double hydraulic cylinders and achieve minimum displacement difference.By comparing the control methods of single-cylinder electro-hydraulic proportional system and double-cylinder synchronization system,combining sliding mode control constructed by single-cylinder adaptive reaching law and double-cylinder fuzzy adaptive PI synchronization control,a cross-coupling synchronization control method is proposed,which achieves the goal of controllable double cylinder error.Firstly,the open-loop transfer function and the closed-loop control system of single hydraulic cylinder electro-hydraulic proportional system are designeded.Taking the piston rod as the force object,the force situation of the piston rod with double hydraulic cylinders is analyzed.Taking the piston rod as the object,the force situation of the piston rod with double hydraulic cylinders is analyzed,then the mathematical model of the synchronous drive system with double hydraulic cylinders is established.The mathematical model of dual-cylinder synchronous drive system is established,and the dynamic and static characteristics of dual-cylinder synchronous control are studied.Secondly,the cause of the non-linearity of the single cylinder electro-hydraulic proportional system is analyzed,and the dead-time compensation control of the electro-hydraulic proportional valve is carried out.According to the system nonlinearity caused by asymmetric reciprocating process of hydraulic cylinder and friction characteristics of hydraulic cylinder,an sliding mode control algorithm with adaptive reaching law is proposed and applied.The sliding mod e control algorithm based on exponential reaching law is used to control the position of single hydraulic cylinder electro-hydraulic proportional system.And the simulation results show that the single hydraulic cylinder system running with this algorithm has large sliding mode chattering.In order to reduce sliding mode chattering,adaptive reaching law is used to construct sliding mode control.The simulation results show that the sliding mode chattering is obviously reduced and the dynamic performance of the system is improved.Finally,the PI control algorithm is applied to the dual-cylinder synchronization controller,which greatly reduces the dynamic overshoot and static error of the dual-cylinder.The simulation results show that the synchronization o f displacement of two cylinders is improved.But PI controller has poor adaptability.In order to solve the problem of poor synchronous non-linear control effect caused by uncertain factors such as sudden load change or wave impact,a fuzzy adaptive PI con trol algorithm is proposed.Based on the single cylinder control characteristics,a cross-coupled synchronous drive control is adopted and simulated.The simulation results show that the cross-coupled synchronous drive control has a good inhibition effect on the synchronous overshoot caused by the asymmetry of the oil circuit and the eccentric load of the two cylinders,which verifies the effectiveness of the proposed algorithm.