scholarly journals The Modeling and Analysis for the Self-Excited Vibration of the Maglev Vehicle-Bridge Interaction System

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Jinhui Li ◽  
Jie Li ◽  
Danfeng Zhou ◽  
Lianchun Wang
Keyword(s):  
Ride Comfort ◽  
Interaction Model ◽  
Control Unit ◽  
The Self ◽  
Modeling And Analysis ◽  
Maglev Vehicle ◽  
Interaction System ◽  
Excited Vibration ◽  
Vibration Problems ◽  
The Stability

This paper addresses the self-excited vibration problems of maglev vehicle-bridge interaction system which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the whole system. Firstly, two levitation models with different complexity are developed, and the comparison of the energy curves associated with the two models is carried out. We conclude that the interaction model with a single levitation control unit is sufficient for the study of the self-excited vibration. Then, the principle underlying the self-excited vibration is explored from the standpoint of work acting on the bridge done by the levitation system. Furthermore, the influences of the parameters, including the modal frequency and modal damping of bridge, the gain of the controller, the sprung mass, and the unsprung mass, on the stability of the interaction system are carried out. The study provides a theoretical guidance for solving the self-excited vibration problems of the vehicle-bridge interaction systems.

Self-excited vibration problems of maglev vehicle-bridge interaction system

2014 ◽  
Vol 21 (11) ◽  
pp. 4184-4192 ◽  
Author(s):  
Jin-hui Li ◽  
Jie Li ◽  
Dan-feng Zhou ◽  
Pei-chang Yu
Keyword(s):  
Maglev Vehicle ◽  
Interaction System ◽  
Excited Vibration ◽  
Vibration Problems

scholarly journals A Practical Control Strategy for the Maglev Self-Excited Resonance Suppression

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Jinhui Li ◽  
Dong Fang ◽  
Ding Zhang ◽  
Ying Cai ◽  
Qi Ni ◽  
...  
Keyword(s):  
Control Strategy ◽  
Ride Comfort ◽  
Block Diagram ◽  
Current Feedback ◽  
Positive Effects ◽  
Maglev Vehicle ◽  
Interaction System ◽  
Electrical Damping ◽  
The Stability ◽  
Additional Feedback

This paper addresses the control strategy for the suppression of maglev vehicle-bridge interaction resonance, which worsens the ride comfort of vehicle and degrades the safety of the bridge. Firstly, a minimum model containing a flexible bridge and ten levitation units is presented. Based on the minimum model, we pointed out that magnetic flux feedback instead of the traditional current feedback is capable of simplifying the block diagram of the interaction system. Furthermore, considering the uncertainty of the bridge’s modal frequency, the stability of the interaction system is explored according to an improved root-locus technique. Motivated by the positive effects of the mechanical damping of bridges and the feedback channels’ difference between the levitation subsystem and the bridge subsystem, the increment of electrical damping by the additional feedback of vertical velocity of bridge is proposed and several related implementation issues are addressed. Finally, the numerical and experimental results illustrating the stability improvement are provided.

scholarly journals A model of nonlinear DNA-protein interaction system with Cornell potential and its stability

2017 ◽  
Vol 1 (1) ◽  
pp. 62
Author(s):  
Edy Syahroni ◽  
A Suparmi ◽  
C Cari ◽  
Fuad Anwar
Keyword(s):  
Protein Interaction ◽  
Interaction Model ◽  
The State ◽  
Hamiltonian Equation ◽  
Single Chain ◽  
Cornell Potential ◽  
Interaction System ◽  
Dna Protein Interaction ◽  
Dna Chain ◽  
The Stability

<p class="Abstract">The purpose of this study was to determine the model of a interaction system between the DNA with protein. The interaction system consisted of a molecule of protein bound with a single chain of DNA. The interaction between DNA chain, especially adenine and thymine, and DNA-protein bound to glutamine and adenine. The forms of these bonds are adapted from the hydrogen bonds. The Cornell potential was used to describe both of the interactions. We proposed the Hamiltonian equation to describe the general model of interaction. Interaction system is divided into three parts. The interaction model is satisfied when a protein molecule triggers pulses on a DNA chain. An initial shift in position of protein xm should trigger the shift in position of DNA ym, or alter the state. However, an initial shift in DNA, yn, should not alter the state of a rest protein (i.e. xm = 0), otherwise, the protein would not steadily bind. We also investigated the stability of the model from the DNA-protein interaction with Lyapunov function. The stability of system can be determined when we obtained the equilibrium point.</p>

A model of nonlinear DNA-protein interaction system with Cornell potential and its stability

2017 ◽  
Vol 1 (1) ◽  
pp. 62
Author(s):  
Edy Syahroni ◽  
A Suparmi ◽  
C Cari ◽  
Fuad Anwar
Keyword(s):  
Protein Interaction ◽  
Interaction Model ◽  
The State ◽  
Hamiltonian Equation ◽  
Single Chain ◽  
Cornell Potential ◽  
Interaction System ◽  
Dna Protein Interaction ◽  
Dna Chain ◽  
The Stability

<p class="Abstract">The purpose of this study was to determine the model of a interaction system between the DNA with protein. The interaction system consisted of a molecule of protein bound with a single chain of DNA. The interaction between DNA chain, especially adenine and thymine, and DNA-protein bound to glutamine and adenine. The forms of these bonds are adapted from the hydrogen bonds. The Cornell potential was used to describe both of the interactions. We proposed the Hamiltonian equation to describe the general model of interaction. Interaction system is divided into three parts. The interaction model is satisfied when a protein molecule triggers pulses on a DNA chain. An initial shift in position of protein xm should trigger the shift in position of DNA ym, or alter the state. However, an initial shift in DNA, yn, should not alter the state of a rest protein (i.e. xm = 0), otherwise, the protein would not steadily bind. We also investigated the stability of the model from the DNA-protein interaction with Lyapunov function. The stability of system can be determined when we obtained the equilibrium point.</p>

Self-Excited Vibration of a Plate Supported by Air Pressure in a Floating Conveying Machine

2017 ◽  
Author(s):  
Masakazu Takeda ◽  
Masahiro Watanabe
Keyword(s):  
Air Pressure ◽  
The Self ◽  
Plate Motion ◽  
Bottom Surface ◽  
Fluid Force ◽  
Gap Flow ◽  
Excited Vibration ◽  
Unsteady Fluid ◽  
The Stability ◽  
Work Done

This paper presents experiments and an analysis on self-excited vibration of a plate supported by air pressure in a floating conveying machine. In this study, the instability conditions are examined by theoretical analysis in consideration of the effect of compressibility of air in a chamber. The system’s characteristic equation is derived from the plate motion coupled with equations of the gap flow between the plate and the chamber surface. The vibration characteristics and the instability conditions of the self-excited vibration are examined through experiments. The stability of the plate is affected by an air flow rate, a mass of the plate, a spring stiffness of the plate. We clarified those influences on the instability conditions of the self-excited vibration. The unsteady fluid force acting on the plate (bottom surface) is investigated by measuring the unsteady pressure. The local work done by the unsteady fluid force is also clarified. Lastly, the instability mechanism and important parameters of the self-excited vibration are discussed based on the theoretical model and experimental results.

The Influence of Oil-Film Journal Bearings on the Stability of Rotating Machines

1946 ◽  
Vol 13 (3) ◽  
pp. A211-A220
Author(s):  
A. C. Hagg
Keyword(s):  
Rotational Frequency ◽  
Journal Bearings ◽  
The Self ◽  
Stability Criteria ◽  
Oil Film ◽  
Oil Whip ◽  
Upper Limit ◽  
Excited Vibration ◽  
Tilting Pad ◽  
The Stability

Abstract The self-excited vibration caused by the lubricating films of journal bearings and commonly called oil-film whirl or oil whip is discussed. The upper limit of whirling frequency has been found to be one-half rotational frequency in the general case; actually the phenomenon will manifest itself at a frequency which is invariably below this limit. Stability criteria have been developed for certain common systems in terms of bearing and rotor parameters. The tilting-pad bearing of Michell has been established as a so-called “stable” or “nonwhirling” bearing. This bearing and related types are probably the only oil-film journal bearings which are incapable of exciting oil whip, regardless of the system to which they are applied. Qualitatively the results of the paper appear to be in agreement with observations. In certain cases, results have been substantiated experimentally.

Self-excited Vibration Control of the Flexible Planar Parallel 3-RRR Robot

2018 ◽  
Vol 25 (2) ◽  
pp. 351-361
Author(s):  
Zhi-cheng Qiu ◽  
Jie Yang ◽  
Xian-min Zhang
Keyword(s):  
High Speed ◽  
Parallel Robot ◽  
The Self ◽  
Flexible Robot ◽  
Nonlinear Controller ◽  
Control Approach ◽  
Excited Vibration ◽  
Improve Accuracy ◽  
The Stability ◽  
Fuzzy Control Algorithm

A self-excited vibration active control approach for a 3-RRR flexible planar parallel robot is developed to improve accuracy and stability. The 3-RRR parallel flexible robot experimental setup is constructed. From the motion experiments, it is demonstrated that the residual vibration can be converted to self-excited vibration at a high-speed motion, which will affect the stability and positioning precision of the platform. To suppress the self-excited vibration owing to flexibility, friction, backlash, coupling, and other nonlinear factors, a nonlinear controller and a fuzzy control algorithm are designed to attenuate the self-excited vibration. Experiments are conducted in different positions of the 3-RRR flexible parallel robot. The experimental results demonstrate that the investigated control methods can suppress the self-excited vibration effectively.

scholarly journals On the Existence of Self-Excited Vibration in Thin Spur Gears: A Theoretical Model for the Estimation of Damping by the Energy Method

Symmetry ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 664 ◽  
Author(s):  
Yanrong Wang ◽  
Hang Ye ◽  
Long Yang ◽  
Aimei Tian
Keyword(s):  
Axial Force ◽  
Traveling Wave ◽  
The Self ◽  
Spur Gears ◽  
Contact Ratio ◽  
Symmetric Structure ◽  
Modal Damping ◽  
Excited Vibration ◽  
Cyclic Symmetric ◽  
The Stability

The gear is a cyclic symmetric structure, and each tooth is subjected to a periodic mesh force. These mesh forces have the same phase difference tooth by tooth, which can excite gear vibrations. The mechanism of additional axial force caused by gear bending is shown and examined, which can significantly affect the stability of a self-excited thin spur gears vibration. A mechanical model based on energy balance is then developed to predict the contribution of additional axial force, leading to the proposed numerical integration method for vibration stability analysis. By analyzing the change in the system energy, the occurrence of the self-excited vibration is validated. A numerical simulation is carried out to verify the theoretical analysis. The impacts of modal damping, contact ratio, and the number of nodal diameters on the stability boundaries of the self-excited vibration are revealed. The results prove that the backward traveling wave of the driven gear as well as the forward traveling wave of the driving gear encounter self-excited vibration in the absence of sufficient damping. The model can be used to predict the stability of the gear self-excited vibration.

Self-Excited Vibration of a Rotating Hollow Shaft Partially Filled with Liquid

1980 ◽  
Vol 102 (1) ◽  
pp. 185-192 ◽  
Author(s):  
S. Saito ◽  
T. Someya
Keyword(s):  
Viscous Liquid ◽  
Rotor System ◽  
The Self ◽  
Hollow Shaft ◽  
Excited Vibration ◽  
Negative Damping ◽  
The Stability

The self-excited vibration of a rotating hollow shaft partially filled with viscous liquid is investigated. The motion of liquid and the liquid force is analyzed. The stability of the rotor system is calculated and the influences of factors on the stability are studied. Moreover, the mechanism causing the negative damping which is the reason for the instability is discussed.

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