Lateral Stability of Road and Rail Trailers

1969 ◽  
Vol 91 (4) ◽  
pp. 1069-1074 ◽  
Author(s):  
W. B. Diboll ◽  
D. H. Hagen
Keyword(s):  
Degrees Of Freedom ◽  
Damping Ratio ◽  
Stable Operation ◽  
Lateral Stability ◽  
Energy Term ◽  
Lower Velocity ◽  
Pivot Point ◽  
Dimensionless Energy ◽  
Excited Vibration ◽  
Angular Displacements

The conditions for the lateral stability at a highway or rail trailer are investigated analytically and experimentally with a laboratory size trailer. The motion of the trailer is expressed in two degrees of freedom, the lateral and angular displacements of the trailer. The oscillation was found to be a self-excited vibration which is very dependent upon the lateral springing at the towing pivot point. The variables are expressed as dimensionless parameters. For conventional trailer loading, the most important variables are the damping ratio as a function of the Strouhal number, sω/V, and as a function of a dimensionless energy term, μGz/V2. As higher values of sω/V and μGz/V2 are reached (for example, lower velocity), less damping is needed for stable operation. Although the relationships have not been established precisely, there is good correlation.

Study on Lateral Stability of Vehicle-Trailer System Based on Multi-Body Dynamic Simulation

2013 ◽  
Vol 765-767 ◽  
pp. 345-350
Author(s):  
Ai Jun Ren ◽  
Zhi Cheng Wu ◽  
Jie Bao
Keyword(s):  
Dynamic Model ◽  
Critical Velocity ◽  
Degrees Of Freedom ◽  
Structural Parameters ◽  
Damping Ratio ◽  
Dynamic Responses ◽  
Lateral Stability ◽  
Linear Dynamic ◽  
Multi Body ◽  
Body Dynamic

With a classical 4 degrees of freedom linear dynamic model of vehicle-trailer system in the yaw plane, preliminary study on lateral stability is carried out by means of analyzing systems damping ratio. The results show that structural parameters have important influence on lateral stability of vehicle-trailer system. Based on that study, a concept of critical velocity with zero damping ratio as an index is present. With the help of MSC.ADAMS, a multi-body dynamic model of a real vehicle-trailer system is built subsequently and the dynamic responses of vehicle-trailer system running on flat road and rough road is simulated respectively. The simulation results indicated that the characteristics of lateral stability of both of the linear dynamic model and the multi-body dynamic model running on flat road are similar. The critical velocity of multi-body dynamic model running on rough road decreases due to the disturbance from road. Since effects of road, nonlinear wheels, suspension structure and load transfer are taken into consideration, multi-body dynamic model of vehicle-trailer system running on the rough road could be more perfectly characterizing the lateral stability of vehicle-trailer system.

Control of processing at multi-tool two-support setup

2020 ◽  
pp. 67-73
Author(s):  
N.D. YUsubov ◽  
G.M. Abbasova
Keyword(s):  
Degrees Of Freedom ◽  
Factor Model ◽  
Angular Displacement ◽  
Factor Models ◽  
Technological System ◽  
Displacement Control ◽  
Model Accuracy ◽  
Six Degrees Of Freedom ◽  
Angular Displacements ◽  
And Control

The accuracy of two-tool machining on automatic lathes is analyzed. Full-factor models of distortions and scattering fields of the performed dimensions, taking into account the flexibility of the technological system on six degrees of freedom, i. e. angular displacements in the technological system, were used in the research. Possibilities of design and control of two-tool adjustment are considered. Keywords turning processing, cutting mode, two-tool setup, full-factor model, accuracy, angular displacement, control, calculation [email protected]

Stability of Ring-Type MEMS Gyroscopes Subjected to Stochastic Angular Speed Fluctuation

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Samuel F. Asokanthan ◽  
Soroush Arghavan ◽  
Mohamed Bognash
Keyword(s):  
Angular Velocity ◽  
Degrees Of Freedom ◽  
Microelectromechanical Systems ◽  
Damping Ratio ◽  
Operating Conditions ◽  
System Stability ◽  
System Response ◽  
Ring Type ◽  
Mems Gyroscopes ◽  
The Stability

Effect of stochastic fluctuations in angular velocity on the stability of two degrees-of-freedom ring-type microelectromechanical systems (MEMS) gyroscopes is investigated. The governing stochastic differential equations (SDEs) are discretized using the higher-order Milstein scheme in order to numerically predict the system response assuming the fluctuations to be white noise. Simulations via Euler scheme as well as a measure of largest Lyapunov exponents (LLEs) are employed for validation purposes due to lack of similar analytical or experimental data. The response of the gyroscope under different noise fluctuation magnitudes has been computed to ascertain the stability behavior of the system. External noise that affect the gyroscope dynamic behavior typically results from environment factors and the nature of the system operation can be exerted on the system at any frequency range depending on the source. Hence, a parametric study is performed to assess the noise intensity stability threshold for a number of damping ratio values. The stability investigation predicts the form of threshold fluctuation intensity dependence on damping ratio. Under typical gyroscope operating conditions, nominal input angular velocity magnitude and mass mismatch appear to have minimal influence on system stability.

Lateral Stability Analysis for Car-Trailer Combinations

2016 ◽  
Author(s):  
Eungkil Lee ◽  
Tao Sun ◽  
Yuping He
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Linear Stability Analysis ◽  
Parametric Study ◽  
Degrees Of Freedom ◽  
Linear Quadratic Regulator ◽  
Lateral Stability ◽  
Linear Quadratic ◽  
Lqr Control ◽  
Ct System

This paper presents a parametric study of linear lateral stability of a car-trailer (CT) combination in order to examine the fidelity, complexity, and applicability for control algorithm development for CT systems. Using MATLAB software, a linear yaw-roll model with 5 degrees of freedom (DOF) is developed to represent the CT combination. In the case of linear stability analysis, a parametric study was carried out using eigenvalue analysis based on a linear yaw-roll CT model with varying parameters. Built upon the linear stability analysis, an active trailer differential braking (ATDB) controller was designed for the CT system using the linear quadratic regulator (LQR) technique. The simulation study presented in this paper shows the effectiveness of the proposed LQR control design and the influence of different trailer parameters.

Numerical Investigation of the Influence of Friction Coefficient on Brake Groan

2010 ◽  
Vol 44-47 ◽  
pp. 1923-1927 ◽  
Author(s):  
Xian Jie Meng
Keyword(s):  
Nonlinear Dynamics ◽  
Friction Coefficient ◽  
Degrees Of Freedom ◽  
Equilibrium Points ◽  
Static Friction ◽  
Kinetic Friction ◽  
Dynamics Model ◽  
Excited Vibration ◽  
Nonlinear Dynamics Model ◽  
The Stability

A two degrees of freedom nonlinear dynamics model of self-excited vibration induced by dry-friction of brake disk and pads is built firstly, the stability of vibration system at the equilibrium points is analyzed using the nonlinear dynamics theory. Finally the numerical method is taken to study the impacts of friction coefficient on brake groan. The calculation result shows that with the increase of kinetic friction coefficient /or the decrease of difference value between static friction coefficient and kinetic friction coefficient can prevent or restrain self-excited vibration from happening.

A Study on Leakage Flow Induced Vibration From Engineering Viewpoint

2015 ◽  
Author(s):  
Fumio Inada
Keyword(s):  
Damping Ratio ◽  
Axial Flow ◽  
Engineering System ◽  
Dimensional System ◽  
Leakage Flow ◽  
Fluid Inertia ◽  
Flow Induced Vibration ◽  
One Dimensional ◽  
Annular Gap ◽  
Excited Vibration

Leakage-flow-induced vibration for a relatively short gap is studied analytically to provide useful information to design structures that include a leakage flow. The relationship between the analysis of a one-dimensional system and that of an annular gap is explained first. Then, the mechanism of flutter-type instability is reproduced from previous study after correcting an error. Finally, the self-excited vibration potential of an engineering system is shown from sample calculations. It is shown that an axial flow becomes dominant in the short-gap approximation, and in this case, the analysis of a one-dimensional flow can be expanded to that of an annular flow. The result that negative damping can occur in the case of a divergent passage owing to the delay induced by fluid inertia was obtained from a previous study. It was suggested analytically that the damping ratio could become negative and its absolute value could become more than 10% in a system that is frequently encountered in a plant, if the natural frequency decreases. The value could be sufficient to generate self-excited vibration.

Impact of Large Scale Wind Power Transmission on System Dynamic Stability

2013 ◽  
Vol 448-453 ◽  
pp. 2535-2539
Author(s):  
Jun Cheng ◽  
Qiang Yang ◽  
Tao Zhu ◽  
Ai Meng Wang ◽  
Xue Feng Hu ◽  
...  
Keyword(s):  
Power System ◽  
Dynamic Stability ◽  
Large Scale ◽  
Wind Farm ◽  
System Analysis ◽  
Power Transmission ◽  
Damping Ratio ◽  
Wind Farms ◽  
Stable Operation ◽  
Large Area

With the scale of the wind farm growing fast, its impact on the power system has become increasingly apparent. So the research has a significant meaning on the characteristics of dynamic stability of the power system which contains wind farms, and the stable operation of the large area interconnected power grid. In this paper it realized the application of the double-fed wind turbine grid model by using power system analysis software PSD-BPA. The analysis of the generator power Angle curve which indicate the state after the failure of N-1 shows as follows: with the wind farms integration on the grid, the damping ratio is decreased slightly but little change after the system failure of N-1, which is still live up to the standard of grid stability.

Stability Regions of Vehicle Lateral Dynamics: Estimation and Analysis

2020 ◽  
Vol 143 (5) ◽  
Author(s):  
Yiwen Huang ◽  
Wei Liang ◽  
Yan Chen
Keyword(s):  
Load Transfer ◽  
Equilibrium Points ◽  
Longitudinal Velocity ◽  
Linearization Method ◽  
Stability Control ◽  
Stable Operation ◽  
Lateral Stability ◽  
Ground Vehicles ◽  
Stability Regions ◽  
Road Friction

Abstract A new method is proposed to estimate and analyze the vehicle lateral stability region, which provides a direct and intuitive demonstration for the safety and stability control of ground vehicles. Based on a four-wheel vehicle model and a nonlinear two-dimensional (2D) analytical LuGre tire model, a local linearization method is applied to estimate the vehicle lateral stability regions by analyzing the vehicle stability at each operation point on a phase plane, which includes but not limited to the equilibrium points. As the collections of all the locally stable operation points, the estimated stability regions are conservative because both vehicle and tire stability are simultaneously considered, which are especially important for characterizing the stability features of highly/fully automated ground vehicles (AGV). The obtained lateral stability regions can be well explained by the vehicle characteristics of oversteering and understeering in the context of vehicle handling stability. The impacts of vehicle lateral load transfer, longitudinal velocity, tire-road friction coefficient, and steering angle on the estimated stability regions are presented and discussed. To validate the correctness of the estimated stability regions, a case study by matlab/simulink and CarSim® co-simulation is presented and discussed.

Finite Element Model Based Full Spectrum Response Analysis of a Cracked Rotor With Internal and External Damping

2019 ◽  
Author(s):  
Dipendra Kumar Roy ◽  
Rajiv Tiwari
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Rotor System ◽  
Response Analysis ◽  
Stable Operation ◽  
Internal Damping ◽  
Full Spectrum ◽  
Fault Parameters ◽  
Spectrum Response

Abstract The ratio of internal and external damping is one of the important fault parameters and it leads to instability of a rotor shaft at higher spin speeds. The crack in a rotor is one of the sources of its instability due to the crack internal damping. A rotor with crack internal damping that originates from the rubbing action between the two crack faces. For a sustained stable operation of the rotor, it is imperative to analyze rotor parameters such as the internal and external damping and other parameters, like the additive crack stiffness and disc eccentricity. Therefore, the present work considers a full spectrum response analysis of a transverse cracked shaft based on the finite element method. The rotary and translations of inertia are considered including of gyroscopic effect in the rotor system. The transverse crack is modeled based on the switching crack assumption. The crack in the rotor gives forcing with multiple harmonics with the forward and backward. The equation of motion has been developed for the rotor system having four degrees of freedom at each node and using MATLAB™ Simulink the responses are generated for a numerical example.

Numerical Analysis for Galloping of Iced Quad Bundle Conductors

2012 ◽  
Vol 226-228 ◽  
pp. 30-34
Author(s):  
Jun Yan Cai ◽  
Xi Jun Liu ◽  
Su Xia Zhang
Keyword(s):  
Numerical Analysis ◽  
Degrees Of Freedom ◽  
Damping Ratio ◽  
Simplified Model ◽  
Fluid Density ◽  
Spring Stiffness ◽  
Critical Wind Velocity ◽  
Line Path ◽  
Stiffness And Damping ◽  
Three Degrees Of Freedom

In order to attain the purpose of anti-galloping, a simplified model for iced quad bundle conductors of three degrees of freedom in vertical, horizontal and torsional directions is established by means of the Hamilton principle, in which the effect of spacers stiffness and damping is considered. Based on the model, the influence of related parameters such as fluid density, damping ratio on conductor galloping amplitude and critical wind velocity is analyzed. Simultaneously, the relation curve between elastic property of spacers and conductor galloping is obtained. The results indicate that the conductor galloping can be weakened to some degree with the proper enlargement of damping ratio, the reasonable setting of spring stiffness on spacers and the avoidance of areas such as the wind outlet and windward as much as possible when choosing the line path and so on.

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