Modal analysis and dynamic shimmy behavior of vehicle–road system

2021 ◽  
pp. 107754632110482
Author(s):  
Heng Wei ◽  
Jianwei Lu ◽  
Lei Shi ◽  
Hangyu Lu ◽  
Shengyong Ye
Keyword(s):  
Modal Analysis ◽  
Degrees Of Freedom ◽  
Front Wheel ◽  
System Stability ◽  
Largest Lyapunov Exponent ◽  
The Road ◽  
Road Roughness ◽  
Measurement Results ◽  
Wheel Track ◽  
Road System

To analyze the influence of the road roughness excitation on vehicle shimmy, a 12 degrees-of-freedom dynamic model of vehicle–road system is developed. The Hopf bifurcation theory is used to study the system stability. On this basis, the natural frequency and modal properties of the vehicle system are elaborated. It can be found that the roll mode plays a crucial role in the vehicle stability. Then, the dynamic shimmy behavior exposed to the sinusoidal and random road roughness excitations is investigated with the help of the modal analysis and the largest Lyapunov exponent. Furthermore, the numerical results are verified through the measurement results, and the influence of the front wheel track on vehicle shimmy is also examined. The results show that the decrease of the front wheel track is an effective way to attenuate vehicle shimmy for different road roughness excitations.

Bifurcation analysis of vehicle shimmy system exposed to road roughness excitation

2021 ◽  
pp. 107754632098779
Author(s):  
Heng Wei ◽  
Jian-Wei Lu ◽  
Sheng-Yong Ye ◽  
Hang-Yu Lu
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Averaging Method ◽  
Lagrange Equation ◽  
Response Characteristic ◽  
Lateral Force ◽  
Front Wheel ◽  
The Road ◽  
Road Roughness ◽  
The Stability

The vertical load of the tire has a significant influence on the lateral force, so the influence of the dynamic load on vehicle shimmy should be taken into account. Based on the dynamic model of a quarter vehicle, a three-degrees-of-freedom dynamic model of the shimmy system with consideration of the road roughness excitation is established by applying the second Lagrange equation. The response characteristic of the system is investigated by the numerical simulations. Moreover, the complexification-averaging method is used to obtain the analytical expression of the shimmy angle of the front wheel, and then, the stability of periodic solutions of the system is evaluated based on the bifurcation theory. Finally, the saddle-node bifurcation and Hopf bifurcation of the shimmy system are studied. The influence of the system parameters on the bifurcation characteristic of the system is also investigated, and the results obtained by using the complexification-averaging method are compared with the numerical examples.

scholarly journals Road Roughness Estimation Based on the Vehicle Frequency Response Function

Actuators ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 89
Author(s):  
Qingxia Zhang ◽  
Jilin Hou ◽  
Zhongdong Duan ◽  
Łukasz Jankowski ◽  
Xiaoyang Hu
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Gaussian White Noise ◽  
Estimation Method ◽  
Time Shift ◽  
Ride Quality ◽  
The Road ◽  
Road Roughness ◽  
Measured Response

Road roughness is an important factor in road network maintenance and ride quality. This paper proposes a road-roughness estimation method using the frequency response function (FRF) of a vehicle. First, based on the motion equation of the vehicle and the time shift property of the Fourier transform, the vehicle FRF with respect to the displacements of vehicle–road contact points, which describes the relationship between the measured response and road roughness, is deduced and simplified. The key to road roughness estimation is the vehicle FRF, which can be estimated directly using the measured response and the designed shape of the road based on the least-squares method. To eliminate the singular data in the estimated FRF, the shape function method was employed to improve the local curve of the FRF. Moreover, the road roughness can be estimated online by combining the estimated roughness in the overlapping time periods. Finally, a half-car model was used to numerically validate the proposed methods of road roughness estimation. Driving tests of a vehicle passing over a known-sized hump were designed to estimate the vehicle FRF, and the simulated vehicle accelerations were taken as the measured responses considering a 5% Gaussian white noise. Based on the directly estimated vehicle FRF and updated FRF, the road roughness estimation, which considers the influence of the sensors and quantity of measured data at different vehicle speeds, is discussed and compared. The results show that road roughness can be estimated using the proposed method with acceptable accuracy and robustness.

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.

Modeling of nonlinear torsional vibration of the automotive powertrain

2016 ◽  
Vol 24 (9) ◽  
pp. 1774-1786 ◽  
Author(s):  
Sérgio J Idehara ◽  
Fernando L Flach ◽  
Douglas Lemes
Keyword(s):  
Natural Frequency ◽  
Torsional Vibration ◽  
Degrees Of Freedom ◽  
Front Wheel ◽  
Torsional Stiffness ◽  
Bench Test ◽  
Passenger Car ◽  
Engine Torque ◽  
Friction Moment ◽  
Wheel Drive

A vibration model of the powertrain can be used to predict its dynamic behavior when excited by fluctuations in the engine torque and speed. The torsional vibration resulting from torque and speed fluctuations increases the rattle noise in the gearbox and it should be controlled or minimized in order to gain acceptance by clients and manufactures. The fact that the proprieties of the torsional damper integrated into the clutch disc alter the dynamic characteristic of the system is important in the automotive industry for design purposes. In this study, bench test results for the characteristics of a torsional damper for a clutch system (torsional stiffness and friction moment) and powertrain torsional vibration measurements taken in a passenger car were used to verify and calibrate the model. The adjusted model estimates the driveline natural frequency and the time response vibration. The analysis uses order tracking signal processing to isolate the response from the engine excitation (second-order). It is shown that a decrease in the stiffness of the clutch disc torsional damper lowers the natural frequency and an increase in the friction moment reduces the peak amplitude of the gearbox torsional vibration. The formulation and model adjustment showed that a nonlinear model with three degrees of freedom can represent satisfactorily the powertrain dynamics of a front-wheel drive passenger car.

Welchen Weg nimmt die „Straße der Zukunft“? – Digitalisierung der Straße im Sonderforschungsbereich/Transregio 339 „Digitaler Zwilling Straße“/Which route takes the “Road of the Future”? – Digitalization of the road within the Collaborative Research Center/ Transregio 339 „Digital Twin of the Road System“

Bauingenieur ◽  
2022 ◽  
Vol 97 (01-02) ◽  
pp. 29-37
Author(s):  
Michael Kaliske ◽  
Markus Oeser ◽  
Ines Wollny ◽  
Ronny Behnke
Keyword(s):  
Collaborative Research ◽  
Research Center ◽  
Digital Twin ◽  
The Road ◽  
System P ◽  
The Future ◽  
Road System

Die Mobilität von Menschen und Gütern ist ein wesentlicher Stützpfeiler einer funktionierenden Gesellschaft und Grundlage einer leistungsfähigen Wirtschaft. Die Mobilität im Bereich des Straßenverkehrs ist in ihrer derzeitigen Form mit enormen Herausforderungen auf globaler Ebene konfrontiert (Dauerhaftigkeit, Sicherheit, Effizienz, Ökologie, Kosten, Automatisierung etc.). Im Sonderforschungsbereich/Transregio 339, der von der Deutschen Forschungsgemeinschaft seit Januar 2022 gefördert wird, forschen mehrere Institute der TU Dresden und der RWTH Aachen (Bauwesen-Informatik-Gesellschaft) an einem räumlich wie zeitlich mehrdimensionalen, digitalen Abbild (Realitätsmodell in Raum und Zeit) aus Fahrzeug, Reifen und Fahrbahn. Das Realitätsmodell „Digitaler Zwilling Straße“ ist gekennzeichnet durch die intelligente Verknüpfung aller relevanten Informationen über das System „Straße der Zukunft“, einschließlich physikalischer Materialuntersuchungen, numerischer Simulationen sowie informatorischer und verkehrlicher Daten (Sensordaten, Datenmodelle etc.).

Road Adhesion Coefficient Estimation Based on the Steering Wheel Rebound After Steering

2018 ◽  
Author(s):  
Liangyao Yu ◽  
Sheng Zheng ◽  
Xiaohui Liu ◽  
Jinghu Chang ◽  
Fei Li
Keyword(s):  
Stability Control ◽  
Front Wheel ◽  
Intelligent Vehicles ◽  
Steering Wheel ◽  
Adhesion Coefficient ◽  
The Road ◽  
Whole Process ◽  
Friction Moment ◽  
Stability Control System ◽  
The Coefficient Of Friction

Accurately estimating road adhesion coefficient is very important for vehicle stability control system. In this paper, an innovation method to estimate the road adhesion coefficient is proposed. This method can be used in vehicles without additional sensors. And this method is especially suitable to be used in the intelligent vehicle equipped with steer-by-wire (SBW) system. When vehicle steers, releasing the steering wheel suddenly will result in rebound to a certain angle. When the steer wheel turns the same angle on different road whose adhesion coefficients are different, the front wheel rebound angles are different. The friction moment between the road and tire is the main factor to prevent the tire from turning back, and the coefficient of friction is equal to road adhesion coefficient when the vehicle is stationary. In this paper, the detailed dynamical models describing the whole process of the front wheel and tire rebound are established. Furthermore, the Luenberger reduced-order disturbance observer is established to estimate the friction moment, and then the adhesion coefficient is estimated. The SBW system which is usually equipped in intelligent vehicles can control the steer moment and steer angle accurately. When the steer wheel turns to certain angle, the SBW system is able to stop outputting torque quickly and timely, which is important for improving the experiment accuracy. In this paper, the SBW system is used to conduct an experiment on different roads. The experiment results demonstrate the validity of this method.

The Time Domain Simulation of Non-Stationary Road Roughness

2013 ◽  
Vol 423-426 ◽  
pp. 1238-1242
Author(s):  
Hao Wang ◽  
Xiao Mei Shi
Keyword(s):  
Power Spectrum ◽  
Time Domain ◽  
Ride Comfort ◽  
Time History ◽  
Random Excitation ◽  
Power Spectrum Density ◽  
The Road ◽  
Road Roughness ◽  
Spectrum Density ◽  
History Of

The input of road roughness, which affects the ride comfort and the handling stability of vehicle, is the main excitation for the running vehicle. The time history of the road roughness was researched with the random phases, based on the stationary power spectrum density of the road roughness determined by the standards. Through the inverse Fourier transform, the random phases can be used to get the road roughness in time domain, together with the amplitude. Then, the time domain simulation of the non-stationary random excitation when the vehicle ran at the changing speed, would also be studied based on the random phases. It is proved that the random road excitation for the vehicle with the changing speed is stationary modulated evolution random excitation, and its power spectrum density is the stationary modulated evolutionary power spectrum density. And the numerical results for the time history of the non-stationary random inputs were also provided. The time history of the non-stationary random road can be used to evaluate the ride comfort of the vehicle which is running at the changing speed.

scholarly journals Efektifitas Pembayangan yang dihasilkan Pohon dan Bangunan di Koridor Jalan Perkotaan Untuk Mencapai Kenyamanan Termal

2018 ◽  
Vol 4 (1) ◽  
pp. 65-70
Author(s):  
Jockie Zudhy Fibrianto ◽  
Mochamad Hilmy
Keyword(s):  
Thermal Comfort ◽  
Temperature Difference ◽  
Weather Conditions ◽  
The Sun ◽  
The Road ◽  
Analysis Phase ◽  
Measurement Results ◽  
The Difference ◽  
Road Corridors ◽  
East West

The road corridor in Pontianak City has different shading output depending on the sun orientation. The difference has caused a temperature difference that affects the pedestrian thermal comfort along the corridor. Identification and measurement of shading temperatures that occur due to buildings and trees were carried out for three days in each afternoon with relatively similar weather conditions. The road corridor that becomes the research location was at A. Yani St.-Gajah Mada St.-Tanjung Pura St., which has a North-South orientation and Teuku Umar St.-Diponegoro St.-Sisingamangaraja St., who has an East-West direction. The analysis phase is done by comparing the effectiveness of imagery produced by buildings and trees. After that, the identification and measurement results are compared with Indonesian thermal comfort standards SNI T-14-1993-03 to obtain suitable thermal comfort in the road corridors in Pontianak City.

scholarly journals Effect of Road Profile on Suspension System of Heavy Truck

2019 ◽  
Vol 12 (2) ◽  
pp. 71-75
Author(s):  
Salem F. Salman
Keyword(s):  
Steering System ◽  
Suspension System ◽  
The Road ◽  
Road Profile ◽  
Road Roughness ◽  
Road Type ◽  
Heavy Truck ◽  
Main Factors ◽  
On The Road ◽  
The Stability

All vehicles are affected by the type of the road they are moving on it.  Therefore the stability depends mainly on the amount of vibrations and steering system, which in turn depend on two main factors: the first is on the road type, which specifies the amount of vibrations arising from the movement of the wheels above it, and the second on is the type of the used suspension system, and how the parts connect with each other. As well as the damping factors, the tires type, and the used sprungs. In the current study, we will examine the effect of the road roughness on the performance coefficients (speed, displacement, and acceleration) of the joint points by using a BOGE device.

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