A study on body sway of car-trailer combinations considering dry friction in steering subsystem

2021 ◽  
pp. 095440702110520
Author(s):  
Ning Zhang ◽  
Ke-Ke Geng ◽  
Tian Li ◽  
Jian-Hua Wu ◽  
Guo-Dong Yin
Keyword(s):  
Dynamic Stability ◽  
Dry Friction ◽  
Sliding Friction ◽  
Dynamic Instability ◽  
Lagrange Equation ◽  
Steering System ◽  
Body Sway ◽  
Rotational Inertia ◽  
Nonlinear Dynamic Model ◽  
Steering Characteristics

Considering the stability of vehicle system, static instability and dynamic instability are two different instability problems. Because of the dynamic coupling between car and trailer, the problem of dynamic stability of car-trailer combination (CTC) is more obvious. This instability is called body sway or flutter in engineering, its boundary is often described by dynamic critical speed ( vcrit). It has been proved by experiments that the steering system characteristics have an important impact on the dynamic stability of CTC, but the specific mechanism is not clear. In this paper, the characteristic and influence of steering subsystem are studied for the first time. Firstly, a 6-DOF nonlinear dynamic model of CTC is established by Lagrange equation. The steering subsystem characteristics, incl. stiffness, damping, rotational inertia, and dry friction, are considered in theoretical modeling. On this basis, the influences of steering characteristics, especially the dry friction, on vcrit and axle cornering stiffness of CTC are analyzed. Simulation results show that the vcrit can increase by 16% and 23.2% respectively via adjusting the steering stiffness and the sliding friction factor. Therefore, a fine selection of steering subsystem characteristics can effectively improve the dynamic stability and safety of CTC. The research results of this paper can provide reference for the design of steering system considering dynamic stability.

scholarly journals Dynamic Modeling and Analysis of Nonlinear Compound Planetary System

Machines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 31
Author(s):  
Tingqiong Cui ◽  
Yinong Li ◽  
Chenglin Zan ◽  
Yuanchang Chen
Keyword(s):  
Planetary System ◽  
Lagrange Equation ◽  
Great Influence ◽  
Planetary Gear ◽  
Rotation Frequency ◽  
Rotational Inertia ◽  
Nonlinear Dynamic Model ◽  
Modeling And Analysis ◽  
Time Frequency ◽  
Meshing Stiffness

In the vehicle composite planetary gear transmission system, nonlinear excitations such as time-varying meshing stiffness, backlash and comprehensive error would lead to large vibration and noise, uneven load distribution, unstable operation and other problems. To address these issues, this work focuses on compound planetary gears and develops the bending-torsion coupling nonlinear dynamic model of the system based on the Lagrange equation. There are internal and external multi-source excitations applied to the system. This model is used to study the bending-torsion coupling meshing deformation relationship of each meshing pair along with the translational and torsional directions. The natural frequencies and vibration modal characteristics of the system are extracted from the model, and the influence of rotational inertia and meshing stiffness on the inherent characteristics of the system are studied. The coupling vibration characteristics of the system under operating condition are analyzed in terms of the inherent characteristics and time–frequency characteristics of the system. The simulation results exhibit that the planetary gear system has three modes. The change in natural frequency trajectory has two phenomena: modal transition and trajectory intersection. The main frequencies include engine rotating frequency, meshing frequency and its double frequency, and the rotation frequency and harmonic frequency of the engine have a great influence on the vibration response of the system. Finally, the virtual prototype of the composite planetary system is used to verify the accuracy of the established model from speed, inherent characteristics, meshing force and frequency composition.

A novel electro-hydraulic servo steering system for Ackermann steering of heavy multi-axle vehicle

2021 ◽  
pp. 095440702110633
Author(s):  
Zhizhong Zhang ◽  
Heng Du ◽  
Shumei Chen ◽  
Yuzheng Li ◽  
Han Wang
Keyword(s):  
Test Bench ◽  
Lagrange Equation ◽  
Experimental System ◽  
Steering System ◽  
Nonlinear Dynamic Model ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Cylinder Model ◽  
Hydraulic Servo ◽  
Simulation Results

Ackermann steering is important for the steering performance of heavy multi-axle vehicle. When Ackermann steering condition is not satisfied, it will lead to abnormal tire wear. Traditional trapezoidal mechanism of heavy multi-axle vehicle is a single degree of freedom (DOF) mechanism, which is difficult to completely realize Ackermann steering. In this paper, a new two DOF electro-hydraulic servo steering system (TDEHSSS) by using a variable length tie rod is proposed for solving the issue. First, a complex nonlinear dynamic model of TDEHSSS is established. This model includes the two DOF mechanical model based on a Lagrange equation, the valve-controlled double steering power cylinders model and the valve-controlled tie rod cylinder model. Then, a simulation model is built through MATLAB/Simulink and the simulation results show that TDEHSSS can realize the proposed requirement. At last, a test bench is founded to verify model. It is indicated that the simulation and experimental curves are consistent, showing that mathematical model is in accordance with the experimental system. This research is valuable for analyzing TDEHSSS, designing advanced controllers, and finally realizing Ackermann steering for heavy multi-axle vehicles.

scholarly journals Modelling and Stability Analysis of Articulated Vehicles

2021 ◽  
Vol 11 (8) ◽  
pp. 3663
Author(s):  
Tianlong Lei ◽  
Jixin Wang ◽  
Zongwei Yao
Keyword(s):  
Stability Analysis ◽  
Critical Velocity ◽  
Equations Of State ◽  
Steering System ◽  
Analysis Model ◽  
Nonlinear Dynamic Model ◽  
Equilibrium Equations ◽  
Eigenvalue Method ◽  
Articulated Vehicles ◽  
The Stability

This study constructs a nonlinear dynamic model of articulated vehicles and a model of hydraulic steering system. The equations of state required for nonlinear vehicle dynamics models, stability analysis models, and corresponding eigenvalue analysis are obtained by constructing Newtonian mechanical equilibrium equations. The objective and subjective causes of the snake oscillation and relevant indicators for evaluating snake instability are analysed using several vehicle state parameters. The influencing factors of vehicle stability and specific action mechanism of the corresponding factors are analysed by combining the eigenvalue method with multiple vehicle state parameters. The centre of mass position and hydraulic system have a more substantial influence on the stability of vehicles than the other parameters. Vehicles can be in a complex state of snaking and deviating. Different eigenvalues have varying effects on different forms of instability. The critical velocity of the linear stability analysis model obtained through the eigenvalue method is relatively lower than the critical velocity of the nonlinear model.

Study on Wear-Preventing of Needle Valve in Fuel Injection System Mounted on DME Engine

2011 ◽  
Vol 228-229 ◽  
pp. 1057-1062
Author(s):  
Xin Rong Wen ◽  
Guang De Zhang ◽  
Wei Hua Wang ◽  
Xie Lu ◽  
Sun Jing
Keyword(s):  
Dynamic Stability ◽  
Structural Design ◽  
Fuel Injection ◽  
Dynamic Instability ◽  
Calculation Model ◽  
The Other ◽  
Injection System ◽  
Needle Valve ◽  
Fuel Injection System ◽  
Theoretical Support

The purpose of this paper is to provide theoretical support for the structural design to prevent the wear of needle. The actual wear of the orientation part of the needle in scrapped needles was researched. The presented results showed that the main reason to the wear of the orientation part of needle was the dynamic instability and the abrasives enter into the surface of orientation part which increases the wear, and that the calculation model of dynamic stability was proposed to prevent the wear of needle. This model was a pressure rod, one end of which was fixed, the other was free, and the two ends were pressed on axial force which changes with time. Besides, the classic formula of dynamic stability of pressure rod was changed rationally, so as to correspond with the calculation model. It will play a part in preventing the wear of needle.

Multiple Reflow Influence over the FeCoCrAlTiCuNiMo Coating Obtained by Plasma Metallization on its Wear Resistance under Dry Friction

2021 ◽  
Vol 410 ◽  
pp. 475-481
Author(s):  
Anvar M. Kadyrmetov ◽  
Dmitri A. Popov ◽  
Yevgeny V. Snyatkov
Keyword(s):  
Wear Resistance ◽  
Dry Friction ◽  
Sliding Friction ◽  
Plasma Jet ◽  
Dry Sliding ◽  
Research Results ◽  
Open Atmosphere ◽  
Multicomponent Coating ◽  
Dry Sliding Friction

The article presents the research results of the plasma jet multiple reflow effect over the multicomponent coating FeCoCrAlTiCuNiMo, obtained by plasma metallization in an open atmosphere, on its wear resistance under dry sliding friction. The research results indirectly confirm the influence of the coating entropy over the wear resistance increasing along of the reflow number growth.

Analysis of Elastic Motion Stability of Flexible Manipulator Arm Based on Lyapunov Stability Theory

2014 ◽  
Vol 620 ◽  
pp. 321-329
Author(s):  
Guang Rui Liu ◽  
Wen Bo Zhou ◽  
Rong Fu Liu
Keyword(s):  
Lyapunov Stability ◽  
Stability Theory ◽  
Lagrange Equation ◽  
Lyapunov Stability Theory ◽  
The State ◽  
Flexible Manipulator ◽  
Rotational Inertia ◽  
Control Input ◽  
Motion Stability ◽  
Manipulator Arm

In order to study the elastic motion stability of flexible manipulator arm , to compute the maximum dynamic allowable payload , the partial differential equation of elastic motion of the flexible manipulator arm is solved using the method of Laplace transformation , the dynamic model of flexible manipulator arm carried addition mass on its end position is established ,simplified and truncated using Lagrange equation . the state space expression is established with the state variable and control input and output variable designated , the elastic motion stability rule is built upon and simplified using Lyapunov stability theory . The influence of the end position addition mass and articulation rotational inertia of flexible manipulator arm on its elastic motion stability is analyzed using the stability rule , and the dynamic maximum allowable payload of flexible manipulator arm on its end position is computed in order to guarantee its elastic motion stability . this study is important to the design of robot mechanical manipulator and corresponding drive control system .

Improvement of Wear Resistance of UHMWPE by Adding Solid Lubricating Fillers

2016 ◽  
Vol 712 ◽  
pp. 155-160 ◽  
Author(s):  
Sergey V. Panin ◽  
Lyudmila А. Kornienko ◽  
Vladislav O. Alexenko ◽  
Larisa R. Ivanova
Keyword(s):  
Wear Resistance ◽  
Dry Friction ◽  
Sliding Friction ◽  
Weight Fraction ◽  
Dry Sliding ◽  
Polyethylene Matrix ◽  
Permolecular Structure ◽  
Uhmwpe Composites ◽  
Ultra High Molecular Weight ◽  
Tribotechnical Characteristics

For estimating effectiveness of adding solid fillers for composites with ultra-high molecular weight polyethylene matrix tribotechnical characteristics of UHMWPE mixture with graphite, molybdenum disulfide and polytetrafluoroethylene were investigated under dry friction, boundary lubrication and abrasion. The optimum filler weight fraction was determined in terms of increasing wear resistance. Permolecular structure and surface topography of wear tracks for UHMWPE composites with different weight fraction of the fillers was studied. The mechanisms of wear of polymeric composites “UHMWPE-graphite”, “UHMWPE-PTFE” and “UHMWPE-MoS2” under dry sliding friction and abrasive wear are discussed.

Dynamic Instability of a High-Speed Planing Boat Model

2000 ◽  
Vol 37 (03) ◽  
pp. 146-152
Author(s):  
Eric Thornhill ◽  
Brian Veitch ◽  
Neil Bose
Keyword(s):  
Dynamic Stability ◽  
High Speed ◽  
Research Council ◽  
Dynamic Instability ◽  
National Research Council ◽  
Scale Model ◽  
Clear Water ◽  
Towing Tank ◽  
Stability Limits ◽  
Resistance Tests

A series of bare-hull resistance and self-propulsion tests were carried out on a 1/8 scale model of a 11.8 m long, waterjet-propelled planing hull in the clear water towing tank at the National Research Council of Canada's Institute for Marine Dynamics. The bare-hull resistance tests, performed with the waterjet inlets closed, spanned a range of eight model velocities and nine ballast conditions consisting of three displacements each with three positions of the longitudinal center of gravity. The hull was then fitted with two model waterjet thrusters and tested over the same speeds and ballast conditions. Dynamic instability, or porpoising, was seen during certain high-speed tests. A discussion of this behavior and its relation to published dynamic stability limits is given.

scholarly journals Ternary Logic of Motion to Resolve Kinematic Frictional Paradoxes

Entropy ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 620 ◽  
Author(s):  
Michael Nosonovsky ◽  
Alexander D. Breki
Keyword(s):  
Dry Friction ◽  
Sliding Friction ◽  
Rigid Bodies ◽  
Newtonian Mechanics ◽  
Stability Criteria ◽  
Ternary Logic ◽  
Elastic Bodies ◽  
Logic Approach ◽  
Frictional System ◽  
Painlevé Paradoxes

Paradoxes of dry friction were discovered by Painlevé in 1895 and caused a controversy on whether the Coulomb–Amontons laws of dry friction are compatible with the Newtonian mechanics of the rigid bodies. Various resolutions of the paradoxes have been suggested including the abandonment of the model of rigid bodies and modifications of the law of friction. For compliant (elastic) bodies, the Painlevé paradoxes may correspond to the friction-induced instabilities. Here we investigate another possibility to resolve the paradoxes: the introduction of the three-value logic. We interpret the three states of a frictional system as either rest-motion-paradox or as rest-stable motion-unstable motion depending on whether a rigid or compliant system is investigated. We further relate the ternary logic approach with the entropic stability criteria for a frictional system and with the study of ultraslow sliding friction (intermediate between the rest and motion or between stick and slip).

scholarly journals Dynamic Stability Discrimination Method for Concrete Dam under Complex Geological Conditions

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Liaojun Zhang ◽  
Tianxiao Ma ◽  
Hanyun Zhang ◽  
Dongsheng Chen
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Dynamic Instability ◽  
Limit Equilibrium ◽  
Element Model ◽  
Safety Factors ◽  
Stability Calculation ◽  
Dam Foundation ◽  
Geological Conditions ◽  
Dam Foundations

The instability of dams will bring immeasurable personal and property losses to the downstream, so it has always been a trendy topic worthy of investigation. Currently, the rigid body limit equilibrium method is the most commonly used method for the dynamic stability analysis of dams. However, under the action of earthquakes, the instability of the integral dam-foundation system threatens the safety of the dams and is of great concern. In this paper, a stability analysis method that can reflect the complex geological structural forms of dam foundations is proposed in this paper. The advantages are that this method deals with the difficulty in assuming sliding surfaces and the lack of quantitative criteria for the dynamic instability analysis of dams with complex geological structural forms of dam foundations. In addition, through the method, the sliding channels that may appear in the dam foundations can be automatically searched under random earthquake action, and the safety factors of the dynamic instability of dams be quantitatively obtained. Taking a high RCC gravity dam under construction in China as an example, the proposed method is applied to the three-dimensional finite element model of the dam-foundation system of this dam, and then the dynamic stability calculation is carried out. Through this method, the formation process of the dam foundation’s plastic zone and the failure of sliding channels with different strength reduction coefficients are studied on and analyzed detailedly, and the quantitative acquisition of the safety factors is realized. The results show that the method is reasonable and feasible, and helps provide a new idea and method for the dynamic stability analysis of dams.

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