scholarly journals Classification Scheme for Random Longitudinal Road Unevenness Considering Road Waviness and Vehicle Response

2009 ◽  
Vol 16 (3) ◽  
pp. 273-289 ◽  
Author(s):  
Oldřich Kropáč ◽  
Peter Múčka
Keyword(s):  
Correction Factor ◽  
Ride Comfort ◽  
Vibration Response ◽  
Suitable Alternative ◽  
The Road ◽  
Novel Approach ◽  
Power Spectral ◽  
Road Profile ◽  
Basic Parameters ◽  
Single Number

A novel approach to the road unevenness classification based on the power spectral density with consideration of vehicle vibration response and broad interval of road waviness (road elevation PSD slope) is presented. This approach enables transformation of two basic parameters of road profile elevation PSD (unevenness index,C, and waviness,w) into a single-number indicatorCwwhen using a correction factorKwaccounting forw. For the road classification proposal two planar vehicle models (passenger car and truck), ten responses (reflecting ride comfort, dynamic load of road and cargo, ride safety) and three different vehicle velocities have been considered. The minimum of ten estimated vibration response ranges sum for a broad waviness interval typical for real road sections (w= 1.5 to 3.5) has been used for the correction factor estimation. The introduced unevenness indicator,Cw, reflects the vehicle vibration response and seems to be a suitable alternative to the other currently used single-number indicators or as an extension of the road classification according to the ISO 8608: 1995, which is based on constant waviness value,w= 2.

Influence of the road profile accuracy on disturbance compensation in active suspension systems

2021 ◽  
Vol 69 (6) ◽  
pp. 485-498
Author(s):  
Felix Anhalt ◽  
Boris Lohmann
Keyword(s):  
Ride Comfort ◽  
Feedforward Control ◽  
Active Suspension ◽  
Disturbance Compensation ◽  
Critical Factors ◽  
The Road ◽  
Suspension Systems ◽  
Active Suspension Systems ◽  
Road Profile ◽  
Profile Accuracy

Abstract By applying disturbance feedforward control in active suspension systems, knowledge of the road profile can be used to increase ride comfort and safety. As the assumed road profile will never match the real one perfectly, we examine the performance of different disturbance compensators under various deteriorations of the assumed road profile using both synthetic and measured profiles and two quarter vehicle models of different complexity. While a generally valid statement on the maximum tolerable deterioration cannot be made, we identify particularly critical factors and derive recommendations for practical use.

scholarly journals Vehicle response on kinematic excitation

2018 ◽  
Vol 211 ◽  
pp. 13001
Author(s):  
Veronika Valašková ◽  
Jozef Melcer
Keyword(s):  
Spectral Density ◽  
Frequency Domain ◽  
Power Spectral Density ◽  
Engineering Problem ◽  
Kinematic Excitation ◽  
The Road ◽  
Power Spectral ◽  
Road Profile ◽  
Vehicle Response ◽  
On The Road

The vehicle - roadway interaction is actual engineering problem solved on many workplaces in the world. At the present time preference is given to numerical and experimental approaches. Vehicle designers are interested in the vibration of the vehicle and the forces acting on the vehicle. Civil engineers are interested in the load acting on the road. Solution of the problem can be carried out in time or in frequency domain. Road unevenness is the main source of kinematic excitation of the vehicle and therefore the main source of dynamic forces acting both on the road and the vehicle. The offered article deals with one of the possibilities of numerical analysis of the vehicle response in frequency domain. It works with quarter model of the vehicle. For the selected computational model of the vehicle it quantifies the Frequency Response Functions (FRF) of both force and kinematic quantities. It considers the stochastic road profile. The Power Spectral Density (PSD) of the road profile is used as input value for the calculation of Power Spectral Density of the response. All calculations are carried out numerically in the environment of program system MATLAB. When we know the modules of FRF or the Power Response Factors (PRF) of vehicle model the calculation of vehicle response in frequency domain is fast and efficient.

Simulation of Bus Ride Comfort under the Excitation of Road Irregularity

2012 ◽  
Vol 510 ◽  
pp. 249-254 ◽  
Author(s):  
Jin Feng ◽  
Yuan Hua Chen
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Ride Comfort ◽  
Temporal Frequency ◽  
Vertical Vibration ◽  
Fe Model ◽  
Analysis Method ◽  
The Road ◽  
Power Spectral ◽  
Bus Structure

Bus vibration is studied by the finite element method (FEM) base on bus structure model. The bus mathematical model of vertical vibration is established and the vibration response variables were deduced with the modal analysis method. The finite element (FE) model is established and decoupled. The transformational relation between spatial frequency displacement power spectral density (PSD) and temporal frequency displacement PSD and the sampling characteristics of the road irregularity PSD in numerical computation are discussed. Road irregularity load is modeled in software. The FE model is solved using modal analysis method and the acceleration PSD of each keypoint can be gained. Finally, a road test experiment is carried on to verify the simulation results. The example indicated that study on vehicle ride comford by FEM has instructive meaning.

The Research of Road Profile Estimation Based on Acceleration Measurement

2012 ◽  
Vol 226-228 ◽  
pp. 1614-1617 ◽  
Author(s):  
Ye Chen Qin ◽  
Ji Fu Guan ◽  
Liang Gu
Keyword(s):  
Dynamic Responses ◽  
The Road ◽  
Physical Measurements ◽  
Power Spectral ◽  
Road Profile ◽  
Road Roughness ◽  
Power Spectral Densities ◽  
Profile Estimation ◽  
The Relationship ◽  
Unsprung Mass

To get the certain response of vehicle during the driving process, it’s necessary to measure the road irregularities. Existing method of gauging the roughness is based on physical measurements and the instrument is installed under the vehicle, which is expensive and will affect the vehicle dynamic responses. This paper shows an easier method to estimate the road roughness by measuring and calculating the power spectral density (PSD) of unsprung mass accelerations. This approach is possible due to the relationship between these two via a transfer function. By comparing the power spectral densities of estimated road and the standard classes, we can classify the current road classes easily. Besides, this paper also shows that it’s feasible to estimate the road profile by calculating the PSD of unsprung mass accelerations directly.

Ride Comfort Simulation of Minibus under Road Pulse Input

2013 ◽  
Vol 467 ◽  
pp. 570-573 ◽  
Author(s):  
Jie Li ◽  
Yan Lei Zhu ◽  
Shao Wei Chen ◽  
Yong Gang Cui
Keyword(s):  
Ride Comfort ◽  
Simulation Software ◽  
Vibration Response ◽  
Absolute Value ◽  
Pulse Input ◽  
Plane Vibration ◽  
The Road ◽  
Vibration Model ◽  
Chinese Standard ◽  
Response Variables

The plane vibration model of minibus with seven degree-of-freedom and its vibration response variables are established according to the plane and linear assumptions. The road pulse input is expressed based on Chinese standard with number of GB/T4970-2009. Ride comfort simulation software of minibus under road pulse input is developed with Matlab and applied to ride comfort analysis of minibus under road pulse input. A minibus is selected to analyze its ride comfort and the maximum absolute value of the vibration response variables are obtained at the speed from 10 to 60 kmh-1. The results show that the model and software can be used to ride comfort simulation of a minibus under road pulse input.

scholarly journals Simulation of Pavement Random Excitation Based on Harmonic Superposition Method

2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Kehui Ma ◽  
Yongguo Zhang ◽  
Xü Zhen
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Ride Comfort ◽  
Random Excitation ◽  
Superposition Method ◽  
Generation Model ◽  
The Road ◽  
Power Spectral ◽  
Control Research ◽  
The Relationship

The road input model is very important in the analysis of vehicle ride comfort and handling stability. Based on the analysis of the relationship between the spatial frequency power spectral density and the time power spectral density of the road, the road signal generation model is established. The simulation is carried out under different vehicle speeds, and the B and C-level random road time excitation signals are generated. The power spectral density is used to compare the simulation results of the model with the road classification standard. The experimental results show that the results are accurate and can provide reliable excitation signals for vehicle control research.

Ride Comfort of Five-Axle Tractor/Semi-Trailer

2000 ◽  
Author(s):  
Zhenyu Jiang ◽  
Moustafa El-Gindy ◽  
Donald Streit
Keyword(s):  
Ride Comfort ◽  
General Concept ◽  
Ride Quality ◽  
Vertical Acceleration ◽  
Gaussian Random Process ◽  
Long Distance ◽  
Power Spectral ◽  
Road Profile ◽  
Computer Based ◽  
Simulation Results

Abstract The issue of ride comfort for vehicle operations has recently generated considerable interest especially in heavy vehicle systems since long-distance drivers are more likely to experience high levels of vibration. This paper introduces the general concept of vibration-related health problems, discusses ride comfort assessment criteria and methods, and then focuses on the methodology of using computer simulation to analyze ride comfort. The computer-based ride comfort model can be divided into three sub-models: vehicle model, driver/seat model, and road profile input model. Several vehicle models and driver/seat models are reviewed and detailed modeling techniques are introduced. A five-axle tractor/semi-trailer/driver combination ride comfort simulation model is developed in this paper using the software DADS. Both four-spring tandem suspension and independent air spring suspension are studied. Road profiles are assumed as static zero mean Gaussian random process. Vertical acceleration at the interface between seat and driver body is obtained from simulation results. Power spectral density and root mean square (RMS) vertical acceleration are calculated based on simulation results. RMS acceleration at ISO classified good and average roads are compared with ISO 8-hour fatigue vibration limit. It is found that RMS acceleration of this particular vehicle simulated in this paper is below the ISO 8-hour fatigue limit for both good and average roads when traveling at the speed of fifty miles per hour. This implies a good ride comfort. Axle dynamic load coefficients (DLC) are calculated for four suspension configurations that are combinations of air springs and steel springs. Results show that large DLC doesn’t necessarily indicate bad ride quality.

scholarly journals Vibration Control of Semi-Active Suspension System using Modified Skyhook with Advanced Firefly Algorithm

2021 ◽  
Vol 2129 (1) ◽  
pp. 012014
Author(s):  
M H Ab Talib ◽  
I Z Mat Darus ◽  
H M Yatim ◽  
M S Hadi ◽  
N M R Shaharuddin ◽  
...  
Keyword(s):  
Firefly Algorithm ◽  
Ride Comfort ◽  
Active Suspension ◽  
The Body ◽  
Matlab Simulation ◽  
The Road ◽  
Vehicle System ◽  
Road Profile ◽  
Control Scheme ◽  
Suspension Control

Abstract The semi-active suspension (SAS) system is a partial suspension device used in the vehicle system to improve the ride comfort and road handling. Due to the high non-linearity of the road profile disturbances plus uncertainties derived from vehicle dynamics, a conventional Skyhook controller is not deemed enough for the vehicle system to improve the performance. A major problem of the implementation of the controller is to optimize a proper parameter as this is an important element in demanding a good controller response. An advanced Firefly Algorithm (AFA) integrated with the modified skyhook (MSky) is proposed to enhance the robustness of the system and thus able to improve the vehicle ride comfort. In this paper, the controller scheme to be known as MSky-AFA was validated via MATLAB simulation environment. A different optimizer based on the original firefly algorithm (FA) is also studied in order to compute the parameter of the MSky controller. This control scheme to be known as MSky-FA was evaluated and compared to the proposed MSky-AFA as well as the passive suspension control. The results clearly exhibit more superior and better response of the MSky-AFA in reducing the body acceleration and displacement amplitude in comparison to the MSky-FA and passive counterparts for a sinusoidal road profile condition.

Load Identification Through Wavelet Parameterization

2001 ◽  
Author(s):  
T. Patrik Nordberg
Keyword(s):  
A Priori ◽  
Linear Optimization ◽  
Unknown Parameters ◽  
The Road ◽  
Novel Approach ◽  
Road Profile ◽  
Simulation Error ◽  
Load Location ◽  
And Performance ◽  
Error Method

Abstract A novel approach based on a simulation error method using a wavelet parameterization is assessed. The present study focuses on the case where the load location is known a priori as it is for the interaction between the road profile and the tyre patch for an automotive vehicle. The proposed method is a time domain technique and the resulting inverse problem is discussed from the viewpoint of two different parameterization approaches. One approach concerns Fourier coefficients and the other advocates the use of wavelet coefficients. The discretized road profile is parameterized into coefficients which greatly reduces the number of unknown parameters in the resulting non-linear optimization problem. Sensor locations are chosen in accordance with the concept of identifiability. Finally, a numerical five degree-of-freedom system illustrates the applicability and performance of the method.

Skyhook control strategy for vehicle suspensions based on the distribution of the operational conditions

2021 ◽  
pp. 095440702110065
Author(s):  
Georgios Papaioannou ◽  
Dimitrios Koulocheris ◽  
Efstathios Velenis
Keyword(s):  
Control Strategy ◽  
Performance Metrics ◽  
Ride Comfort ◽  
Damping Ratio ◽  
Cumulative Distribution ◽  
Operational Conditions ◽  
The Road ◽  
Vehicle Suspensions ◽  
Road Profile ◽  
The Impact

In this work, a novel distribution-based control strategy of semi-active vehicle suspensions is tested under different conditions. The novelty lies in the use of an appropriate threshold in the operational condition of the control algorithm, with which the operational conditions severity is quantified and the state of the damper is controlled according to the magnitude of the operational conditions and not their sign. The value of the threshold depends on the vibrations induced to the sprung mass by the road profile. In order to be evaluated, the operational conditions of the algorithm are fitted to a t-student distribution. The cumulative distribution function of this distribution is used in order to decrease the fraction of the sample operating with the damper’s stiff state. The strategy is applied to traditional SH control algorithms and is tested using a quarter car model excited by different road excitations. A sensitivity analysis for various threshold values is performed, investigating the impact of adopting the cumulative distribution functioned (CDF) controller to various performance metrics. The results illustrate an increase of up to 13% in the ride comfort of the passengers and increase of 6% in the road holding of the vehicle. Both are achieved by minimizing the switches of the damping ratio up to 80%.

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