Research On Electro-hydraulic Control Technology For Security Devices Of Large Shiplift

Shiplift is a navigation building that helps a ship to overcome the waterhead of a channel by its mechanical device,through which the navigation problem of different water systems and the hydropower stations is solved.Wire rope hoist vertical shiplift is the main type of large shiplift at home and abroad.The ship chamber with water is driven by the electric winch to work at tens of meters or even hundreds meters' lift range.Shiplift is a kind of large passenger and cargo dual carrying equipment,its operation safety and reliability has been a topic of great concern in the industry.Because of the elasticity of wire rope and the flowability of the water,how to ensure the stability and safety of the huge ship chamber with water under flexible support system in high altitude is the key to ensure the safety of wire rope hoist shiplift.Locking device for connection and ship chamber leveling device are important hydraulic devices for ensuring the safety of the wire rope hoist vertical ship lift.Therefore,the dissertation will focus on load characteristics and electro-hydraulic control methods of the locking device for connection,ship chamber leveling device and other security hydraulic device on the wire rope hoist vertical shiplift through theoretical modeling,simulation analysis and experimental verification method.The main contents of this dissertation are as follows:In chapter 1,First,the construction significance of shiplift,the working principle of shiplift and its development status at home and abroad are summarized;Then,the research status of fluid structure interaction,free liquid sloshing and shiplift mechanical characteristics are summarized,which influence the safety of wire rope hoist type vertical shiplift.Finally,the origin,the research significance and the research contents of this dissertation are introduced.In chapter 2,the security technology of wire rope vertical lift shiplift is studied.The traditional safety technologies and innovative safety technology of wire rope hoist lift are introduced from three aspects of electric main hoisting technology,detection technology of ship chamber and upper monitoring.Some new measures to ensure the safety of wire rope hoist lift are puts forward on the basis of practical experience from Silin and Shatuo shiplift.The research emphasis of chaper 2 are the three key hydraulic security devices:locking device for connection,ship chamber leveling device and tumble gate on the ship chamber.The load pressure override control of tumble gate,half-approximation levelling algorithm of ship chamber are put forward,which are implemented and verified in the subsequent part of the dissertation.In chapter 3,the fluid structure interaction between the ship chamber and the water in it is discussed.The sloshing of large quantities of water in the ship chamber is one of the biggest hidden dangers for the safety work of the wire rope vertical shiplift.Due to the low damping of the water,the dynamic response of ship chamber under extern load is more complicated and unpredictable than ordinary solid inertial loads in suspension condition because of complex coupling characteristics between the steel wire rope,the ship chamber and the water.The combining methods of linear potential function and equivalent model method is adopted to study the fluid structure interaction characteristics between the ship chamber and the water.The equivalent mechanical model of the sloshing water is established,and the complex flow field of water is equivalent to a more intuitive rigid body mechanical model.The natural frequency,equivalent quality and the additional force and torque acting on the ship chamber of sloshing water are obtained through the equivalent mechanical model,which are the important dynamic parameters affecting the safety of shiplift.The research results provide a theoretical basis for the design of the main hoist of shiplift,the leveling system and the locking device for connection.In chapter 4,the automatic leveling system of ship chamber is investigated.The leveling system of ship chamber is an unconventional leveling system.It is a space parallel redundant drive system with large inertia,low damping and limited stroke of leveling hydraulic cylinder.The mathematical model of the leveling system is established and the ship chamber levelling algorithm based on the half-approximation method and integral synchronization method is put forward in the dissertation.The half-approximation method contributes to the stable leveling without overshoot oscillation,and the integral synchronization method helps to the space trajectory cooperative control of multiple leveling hydraulic cylinders.In chapter 5,the electro-hydraulic control technology of locking device for connection is studied.The locking device for connection is a new device in order to improve the safety of wire rope hoist shiplift,which is used to bear the additional loads during connection and as clamping device in accident condition to guarantee the safety of the ship chamber.The pressure relief synchronous control of four locking devices for connection is the key to ensure the smooth and safe operation of the shiplift.A new pressure relief synchronous control system for high pressure passive small trapped fluid volumes is proposed in the dissertation,and the performance of its intelligent pressure tracking control strategy and pressure synchronous control strategy is verified through experiments.In chapter 6,the main work of the dissertation is summarized.The innovation points and research conclusions are introduced.Finally,the research prospects on electro-hydraulic control technology for security devices of large shiplift is reviewed.