| The ship lift is a navigable building that overcomes the water level difference on the channel by lifting the ship through mechanical devices,integrating mechanical,hydraulic,automatic control and other technologies.It is composed of upper and lower lock heads,carrier carriages,supporting guiding equipment,lifting mechanisms,safety mechanisms,etc.,and has many characteristics such as complex structure,high requirements for running accuracy,heavy load,and large lifting degree difference.As the core of the ship lift,the lifting mechanism involves the safety of ships and passengers crossing the dam,so it is particularly important to analyze the dynamic characteristics and synchronous control of the lifting mechanism of the large ship lift.In this paper,the lifting mechanism of vertical ship lift is taken as the research object,and according to the design criteria,working conditions and stability requirements of vertical ship lift,the motor,reducer,rack and pinion transmission system and locking device are selected and designed,and a three-dimensional solid model of the lifting mechanism of vertical ship lift is established.Based on the basic knowledge of rigid body dynamics and kinematics,the motion equation of the carrier compartment is established,and the kinetic energy and potential energy of the wire rope,pulley,counterweight and bearing compartment are calculated by combining the kinetic energy and potential energy principle,and then the dynamic equation of the lifting mechanism is established according to the second type of equation of Lagrange.Based on the composition mechanism of the lifting mechanism of the vertical ship lift,a virtual prototype model of the lifting mechanism is created,and the dynamic characteristics of the normal working conditions of the lifting mechanism of the vertical ship lift and the special working conditions such as the misloaded water depth,wind load,and wire rope failure of the ship are simulated according to the actual project,and the dynamic simulation results of each working condition are obtained,combined with the synchronous control theory,the control structure of synchronous lifting of the cabin is designed,and the method of speed-position coupling deviation control is proposed on the basis of speed deviation coupling control.Eight motor control models were built in the Simulink environment to simulate the synchronous control of the lifting process of the ship.The results show that the displacement,velocity fluctuation and pitch angle of the ship in the three directions of the water depth of 5cm,10 cm and 20 cm,and the X,Y,and Z of the carriage are larger than the normal working conditions,and increase with the increase of the misload.Under wind load conditions and wire rope failure conditions,the displacement,velocity fluctuation and pitch angle in the three directions of x,y and z of the carriage were larger than normal working conditions.Under the misload water depth condition and wind load condition,the gear and rack of the lifting mechanism meshes well,and the wire rope breaking condition has the greatest impact on the cabin,which will lead to the eccentric load phenomenon of the cabin,affect the synchronization of the cabin lifting and lowering,and the strategy of speed-position deviation coupling synchronous control can effectively realize the smooth lifting and lowering of the ship compartment and further improve the safety of the ship lift operation. |
