Dynamics Modeling And Vibration Control Of High-speed Elevator Hoisting System

As the transportation of the high-rise building, the elevator has more undetectableinfluences in daily life. There was no doubt that security and comfort are people’s basicrequirements for the performance of elevator. Moreover, due to the defects of the design,manufacture and installation, all kinds of vibration phenomena will occur inevitablyduring the running process of the elevator. And most of the vibration related to theelevator hoisting system. With increase of the elevator hoisting height and speed, thehoisting system is more sensitive to outside interference in the whole running process ofthe elevator. The interference may cause abnormal vibration to the hoisting system. Theconsequences will aggravate the fatigue and wear of the rope, and shorten the service lifeof the rope. At the same time, the vibration may be the source of sounds in the car, theunanticipated vibration of car may bring uncomfortable feeling. And these vibrations canreduce the elevator’s service life and ride comfort. In addition, with the rapid developmentof urbanization process, higher requirements of elevator are brought forward with thedevelopments about security and comfort. However, in order to solve this conflict andhold characteristics and laws of the elevator hoisting system, the dynamic behaviors of thehoisting system must be in-depth and detailed comprehended during the running processof the elevator. Feasible control strategies should be used to control vibration. In this paper,the theoretic analysis, simulation and experiment are combined to investigate the dynamicbehaviors of the elevator hoisting system. At the same time, a controller which candissipate the vibratory energy is derived. Therefore, the study on dynamic behaviors forthe elevator hoisting system provides the theoretical and technical support for the reliableoperation of the hoisting system.The elevator hoisting system is modeled as a taut translating string with a rigid bodyattached at its low end. The nonlinear vibration of elevator hoisting system is investigatedconsidering the multi-body dynamics and the effect of the geometrically non-linearkinematics of deformation. The governing equations of the elevator hoisting system aredeveloped based on the extended Hamilton’s principle. Experiments are performed toevaluate the theoretical model and it is found that the experimental data agree well with the theoretical prediction, which validates the mathematical model of the flexible hoistingsystem.The characteristics of parametric vibration are analyzed based on the couplingvibration model of the elevator hoisting system from three aspects. Firstly, the expressionof total vibration energy of the elevator hoisting system is developed. Lyapunov’s secondmethod are used to analyze the transient stability of the elevator hoisting system. Secondly,the formula of natural frequency of the elevator hoisting system is derived, and theinherent frequency characteristics of hoisting system is analyzed. The causes that thenatural frequency changes in the process of elevator hoisting system running are explained.Thirdly, the influences of structure parameters and running state parameters to the elevatorhoisting system are analyzed in detail.In order to master the vibration characteristics of the hoisting system under theexternal excitation, Finally, the longitudinal-transverse coupled models were built withexternal excitation. The transient responses of the hoisting system were discussed underthe action of rail excitation, traction excitation and parametric excitation. The resultsindicate that the external excitation mainly comes from the factors such as guiding system,traction system and so on, and the factors have more influences on transverse vibration ofthe elevator hoisting system. The structure parameters of the elevator hoisting system maychange during movement of the elevator. The transient resonance may cause when one ofthe hoisting system frequencies coincides with the frequency of external excitation,developing damped beat phenomena. The transient resonance may cause many adverseeffects to the hoisting system. The transient resonance have more influences onlongitudinal vibration of the elevator hoisting system.In order to reduce and control the level of vibration of high-speed elevator hoistingsystem, two different controller are used to restrain the vibration of hoisting system, i.e.,passive control based on rope tension device and active control based on the Lyapunovstability theory. The results of simulation show that the two proposed controller caneffectively restrain vibration of the elevator hoisting systems.To research the vibrations of the elevator, taking into account the contact forcesbetween guide shoe and rail the system dynamic equations of the elevator was developedaccording to Newton’s second law of motion and theorem of moment of momentum. Thecar-frame-rail coupled model may reflect the coupled vibration among the rail, frame andcar and imitate the behavior of contact and separation between guide shoe and rail.All of the results will be beneficial to the theoretic research of the elevator hoistingsystem in the future. All of these results provide an important theoretical foundation forthe studies on ride comfort and security of the elevator. At the same time, they provide some useful means and ideas for impelling the studies on dynamic characteristic andvibration control of the hoisting system.