The Research On Dynamic Model Of Load Vibration System In Vertical Direction And Damping By Drum-speed Tuning

Due to adopting flexible amplitude,the load of wire rope luffing crane is more likely to vibrate in the vertical direction.Relative to load sway,load vibration in vertical direction would cause larger dynamic load,which will cause the dynamic impact on the crane structure.Beside,crane overturning may occur when it laterally operating in boom working range,which could affect the safety of operations.In this paper,the dynamic analysis of the load vertical vibration system of the wire rope luffing crane was carried out.According to the dynamic characteristics of the system,the theoretical dumping method on drum-speed tuning was put forward and a control scheme of drum-speed tuning was studied,that provided a significant guidance to improve the safety of crane operation.The main research contents of this paper includes:(1)Base on lumped-mass method,pendulum motion of load is neglected and the rope is elastic,by using the principle of dynamic balance established the load vibration system dynamic model in vertical direction of amplitude plane respectively in compensating pulley method and cylindrical drum compensation method.Analyzed its dynamic behavior,then put forward a new vibration reduction method by adjusting rotation rate of luffing and hoisting drum to introduce the system damping and theory formula of the drum-speed tuning under two kinds of rope compensation method was deduced.(2)Through numerical calculation of the dynamic model got the relationship between the dynamic model coefficient and boom angle.By comparing the second order vibration frequency of theoretical calculation with modal analysis result in Adams three-dimensional dynamics model to verify the correctness of the theoretical dynamic model in this paper.Using MATLAB to calculate the load vertical vibration system responses in the initial exciting under undamped system and under the two ways damping system with different damping parameters.It showed that the system vibration can be reduced by suitable drum-speed tuning,and got the better damping parameters.(3)Based on the dynamic model of load vibration system in vertical direction and theory formula of the drum-speed tuning,the conventional PID control system were designed in the first place?Simulink simulation demonstrated the effectiveness of the control system can reduce load nonworking vibration in vertical direction.And,studied the adaptability of conventional PID controllers by changing the quality of load and the length of hoist rope.Then,on this basis the fuzzy self-adaptive PID controllers was designed,in order to realize the parameters online self-tuning of PID control system.Simulation proved that the fuzzy PID control system has strong adaptability to the variation of model parameters,faster response speed,and improve dynamic performance of this control system.