Self-Excited Torsional Oscillations under Locked-Wheel Braking: Analysis and Experiments

2015 ◽  
Vol 43 (4) ◽  
pp. 276-296
Author(s):  
Chunjian Wang ◽  
Beshah Ayalew ◽  
John Adcox ◽  
Benoit Dailliez ◽  
Tim Rhyne ◽  
...  
Keyword(s):  
Torsional Oscillation ◽  
Friction Model ◽  
Torsional Stiffness ◽  
Torsional Oscillations ◽  
Stribeck Effect ◽  
Vehicle Velocity ◽  
Wheel Model ◽  
Bifurcation Surface ◽  
Torsionally Flexible ◽  
The Stability

ABSTRACT This paper analyzes the effect of tire/vehicle parameters, specifically of tire/suspension torsional stiffnesses, on the stability of self-excited tire torsional oscillations during locked-wheel braking events. Using a torsionally flexible tire-wheel model and a dynamic tire-ground friction model, two system models for tire oscillations are considered: with suspension torsional compliance included in one but excluded in the other. Bifurcation analysis is conducted on both systems to derive the effect of tire/vehicle parameters on the stability. For the system without suspension torsional compliance, it is highlighted that the primary cause of unstable self-excited oscillations is the “Stribeck” effect in tire-ground friction. Based on the parameters obtained experimentally, the bifurcation surface of vehicle velocity with respect to tire/suspension torsional stiffness is also given. The effect of tire/suspension torsional stiffness to the stability of tire torsional oscillation is qualitatively validated via comparisons between locked-wheel braking simulations and experiments with tires with different torsional stiffnesses.

On the Stability of Tire Torsional Oscillations Under Locked-Wheel Braking

2014 ◽  
Author(s):  
Chunjian Wang ◽  
John Adcox ◽  
Beshah Ayalew ◽  
Benoit Dailliez ◽  
Timothy Rhyne ◽  
...  
Keyword(s):  
Normal Load ◽  
Friction Model ◽  
Torsional Stiffness ◽  
Design Stage ◽  
Torsional Oscillations ◽  
Vehicle Suspensions ◽  
Wheel Model ◽  
Torsionally Flexible ◽  
Torsional Instability ◽  
The Stability

This paper deals with the stability of self-excited tire torsional oscillations during locked-wheel braking events. Using a combination of torsionally flexible tire-wheel model and a dynamic tire-ground friction model, it is highlighted that the primary cause of unstable oscillations is the ‘Stribeck’ effect in tire-ground friction. It is also shown analytically that when suspension torsional compliances are negligible, the bifurcation parameters for the local torsional instability include forward speed, normal load and tire radius. In the presence of significant suspension torsional compliance, it is shown that the stability is also affected by suspension torsional stiffness and damping. Furthermore, the tire torsional stiffness becomes an important bifurcation parameter only in the presence of significant suspension compliance. This analysis gives useful insights for the selection of tire sidewall stiffness ranges and their proper matching with targeted vehicle suspensions at the design stage.

A Novel Backstepping Approach for the Attenuation of Torsional Oscillations in Drill Strings

2016 ◽  
Vol 248 ◽  
pp. 85-92 ◽  
Author(s):  
Farooq Kifayat Ullah ◽  
Franklyn Duarte ◽  
Christian Bohn
Keyword(s):  
Torsional Oscillation ◽  
Friction Model ◽  
Drill String ◽  
Cutting Process ◽  
Underactuated System ◽  
Drilling Process ◽  
Control Input ◽  
Nonlinear Phenomenon ◽  
Stick Slip ◽  
Torsional Oscillations

A common problem in the petroleum drilling process is the torsional oscillation generated by the friction present during the cutting process. Torsional oscillations in drill string are particularly difficult to control because the drill string is an underactuated system, it has a very small diameter to length ratio and it is driven at top end with the cutting process at the other end. These factors make the drill string prone to self-excited torsional vibrations caused by the stick-slip of the cutting bit. The system is modeled as a torsional pendulum with two degrees of freedom, where the upper inertia models the top drive and also part of the drilling pipes. The bottom inertia models the bottom hole assembly (BHA). The drill is considered to be a massless torsional spring-damper. The drill string is subjected to friction, which is formulated using a dry friction model. The friction model takes into account Coulomb friction, stiction and Stribeck effect. The latter friction component is the main nonlinear phenomenon that introduces negative damping at the bit; it leads to self-enforcing stick-slip torsional oscillations.In the approach of this work, for the attenuation of these self-excited oscillations a recursive backstepping control strategy is used and it is carried out in continuous time. The main contribution of this work, which is different from the backstepping approaches reported in the literature, is to use a nonlinear/artificial damping as virtual control input. The stability of the system has been proven in the sense of Lyapunov. The goal of the proposed algorithm is to deal the underactuation of the system and to provide a good response for different operating points. The effectiveness and robustness of the controller has been tested in simulations.

Influence of Nonlinear Stiffness on the Dynamics of a Slender Elastic Beam under Torsional Oscillations

2014 ◽  
Vol 706 ◽  
pp. 159-169
Author(s):  
Marcos Silveira ◽  
Bento R. Pontes ◽  
José M. Balthazar
Keyword(s):  
Numerical Algorithms ◽  
Elastic Beam ◽  
Basins Of Attraction ◽  
Torsional Stiffness ◽  
Nonlinear Stiffness ◽  
Torsional Oscillations ◽  
Before And After ◽  
Stiffness Characteristics ◽  
The Stability ◽  
Helical Buckling

This study focuses on analysing the effects of nonlinear torsional stiffness on the dynam-ics of a slender elastic beam under torsional oscillations, which can be subject to helical buckling.The helical buckling of an elastic beam confined in a cylinder is relevant to many applications. Someexamples include oil drilling, medical cateters and even the conformation and functioning of DNAmolecules. A recent study showed that the formation of the helical configuration is a result of onlythe torsional load, confirming that there is a different path to helical buckling which is not related tothe sinusoidal buckling, stressing the importance of the geometrical behaviour of the beam. A lowdimensional model of an elastic beam under torsional oscillations is used to analyse its dynamical be-haviour with different stiffness characteristics, which are present before and after the helical buckling.Hardening and softening characteristics are present, as the effects of torsion and bending are coupled.With the use of numerical algorithms applied to nonlinear dynamics, such as bifurcation diagramsand basins of attraction, it is shown that the nonlinear stiffness can shift the bifurcations and inducechanges in the stability of the desirable and undesirable solutions. Therefore, the proper modellingof these stiffness nonlinearities seems to be important for a better understanding of the dynamicalbehaviour of such beams

Fore-Aft Forces in Tire-Wheel Assemblies Generated by Unbalances and the Influence of Balancing

1991 ◽  
Vol 19 (3) ◽  
pp. 142-162 ◽  
Author(s):  
D. S. Stutts ◽  
W. Soedel ◽  
S. K. Jha
Keyword(s):  
Mathematical Model ◽  
Elastic Foundation ◽  
Torsional Oscillation ◽  
Vertical Direction ◽  
Torsional Stiffness ◽  
Rolling Motion ◽  
Vertical Force ◽  
Horizontal Force ◽  
Wheel Rim ◽  
Open Question

Abstract When measuring bearing forces of the tire-wheel assembly during drum tests, it was found that beyond certain speeds, the horizontal force variations or so-called fore-aft forces were larger than the force variations in the vertical direction. The explanation of this phenomenon is still somewhat an open question. One of the hypothetical models argues in favor of torsional oscillations caused by a changing rolling radius. But it appears that there is a simpler answer. In this paper, a mathematical model of a tire consisting of a rigid tread ring connected to a freely rotating wheel or hub through an elastic foundation which has radial and torsional stiffness was developed. This model shows that an unbalanced mass on the tread ring will cause an oscillatory rolling motion of the tread ring on the drum which is superimposed on the nominal rolling. This will indeed result in larger fore-aft than vertical force variations beyond certain speeds, which are a function of run-out. The rolling motion is in a certain sense a torsional oscillation, but postulation of a changing rolling radius is not necessary for its creation. The model also shows the limitation on balancing the tire-wheel assembly at the wheel rim if the unbalance occurs at the tread band.

XVII.—On a Fuller Test of the Law of Torsional Oscillation

1914 ◽  
Vol 33 ◽  
pp. 177-182
Author(s):  
James B. Ritchie
Keyword(s):  
Torsional Oscillation ◽  
Torsional Oscillations ◽  
The Law ◽  
Image Position

It has been shown in a former paper that an equation of the formcan be applied to give close representation of results in the determination of the law of decrease of torsional oscillations of wires of different materials, when the range of oscillation is large in comparison with the palpable limits of elasticity.

Friction Identification Using Evolution Strategies and Robust Control of Positioning Tables

1999 ◽  
Vol 121 (4) ◽  
pp. 619-624 ◽  
Author(s):  
Seon-Woo Lee ◽  
Jong-Hwan Kim
Keyword(s):  
Static Friction ◽  
Velocity Model ◽  
Friction Model ◽  
Evolution Strategies ◽  
Linear Feedback ◽  
Control Input ◽  
Identification Technique ◽  
Friction Identification ◽  
The Stability ◽  
And Control

This paper presents an identification technique using evolution strategies (ES) for an integrated friction model of a positioning table. The friction model is based on Karnopp’s friction-velocity model with the rising static friction and spring-like property. Using the (μ + λ)-ES, the system parameters are identified with the experimental input and output data. The proposed control law consists of a conventional linear feedback control input, a friction compensation term and a sliding control input. The proposed control scheme can guarantee the stability of the overall system, even in the presence of the external disturbances and the modeling error between the real friction and the identified model. Experiments on an positioning table, called X-Y table, demonstrate the effectiveness of the proposed identification and control schemes.

Vehicle Stability Control in Anti-Lock Braking System on Split-U Road Surface Considering Driver in the Loop

2013 ◽  
Author(s):  
Liangyao Yu ◽  
Changxi You ◽  
Jian Song
Keyword(s):  
Driver Behavior ◽  
Research Work ◽  
Stability Control ◽  
Road Surface ◽  
Control Law ◽  
Vehicle Stability ◽  
Braking System ◽  
Vehicle Stability Control ◽  
Vehicle Velocity ◽  
The Stability

With the introduction and development of Anti-lock Braking System in modern vehicles, remarkable progress in brake efficiency and brake stability has been achieved. However, it is a significant challenge to deal with the control law in certain critical situations, especially on split-μ road surface. In low vehicle velocity, as some standards and regulations specified, the stability in such situation is comparably easy to be achieved. But with the vehicle velocity increasing, the driver behavior contributes a large impact on the trajectory maintenance and easily causes sympathetic vibration of the vehicle because of the unexpected synchronization between the driver input and control law output, which could be very dangerous. This paper presents the research work in vehicle stability control when Anti-lock Braking System is activated at split-μ road surface. The principal contribution of this work is that the driver behavior is taken into account and the control law is tuned to adapt to this situation, which effectively maintains the stability of the vehicle without compromising the brake efficiency.

scholarly journals A theoretical model of torsional oscillations from a flux transport dynamo model

2010 ◽  
Vol 6 (S273) ◽  
pp. 366-368
Author(s):  
Piyali Chatterjee ◽  
Sagar Chakraborty ◽  
Arnab Rai Choudhuri
Keyword(s):  
Magnetic Field ◽  
Theoretical Model ◽  
Lorentz Force ◽  
High Latitude ◽  
Torsional Oscillation ◽  
Sunspot Cycle ◽  
Dynamo Model ◽  
Flux Transport ◽  
Torsional Oscillations ◽  
The Magnetic Field

AbstractAssuming that the torsional oscillation is driven by the Lorentz force of the magnetic field associated with the sunspot cycle, we use a flux transport dynamo to model it and explain its initiation at a high latitude before the beginning of the sunspot cycle.

A Regularized Contact Model for Multibody System Simulation

2016 ◽  
Author(s):  
Albert Peiret ◽  
Farnood Gholami ◽  
József Kövecses ◽  
Josep M. Font-Llagunes
Keyword(s):  
Multibody Systems ◽  
Large Scale ◽  
Multibody System ◽  
Linear Complementarity Problems ◽  
Friction Model ◽  
Computational Performance ◽  
Unilateral Contacts ◽  
Wheel Model ◽  
Friction Models ◽  
Coulomb Model

Simulation of large-scale multibody systems with unilateral contacts requires formulations with which good computational performance can be achieved. The availability of many solver algorithms for Linear Complementarity Problems (LCP) makes the LCP-based formulations a good candidate for this. However, considering friction in contacts asks for new friction models compatible with this kind of formulations. Here, a new, regularized friction model is presented to approximate the Coulomb model, which allows to formulate the multibody system dynamics as a LCP with bounds. Moreover, a bristle approach is used to approximate the stiction force, so that it improves the numerical behaviour of the system and makes it able to handle redundancy coming from the friction interfaces. Several examples using a 3D wheel model has been carried out, and the proposed friction model shows a better approximation of the Coulomb model compared to other LCP-based formulations.

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