Analysis on Usage Comfort of Highway Based on Lateral Acceleration and Lateral Acceleration Change Rate

2013 ◽  
Vol 427-429 ◽  
pp. 320-324 ◽  
Author(s):  
Zheng Yu Wang ◽  
Cheng Bing Li ◽  
Jin Xu
Keyword(s):  
Rigid Body ◽  
Three Dimensional ◽  
Driver Model ◽  
Lateral Acceleration ◽  
Mountainous Area ◽  
Vehicle Model ◽  
Change Rate ◽  
Vehicle Simulation ◽  
Peak Value ◽  
Made In

To control the lateral acceleration of driving vehicle and its rate of growth is always an important part in road geometric design. At present, vehicles are simplified as single rigid body when and are calculated, moreover, the calculation is made in two-dimensional plane, which does not comply with the actuality. In this article, Road-Driver-Vehicle simulation system (RDVS) is applied to get and of driving vehicle on 3 test roads selected from the mountainous area of southwestern China. In RDVS, the dynamic vehicle model is driven on three-dimensional roads under the control of driver model, so it is more close to the real driving. The results show: got from RDVS is bigger than that from single rigid body calculation. As RDVS is more reliable, from single rigid body calculation may cause an insufficient estimation: suppose the driver drives at the designed speed, though the designed speed varies, the peak value of of the three objects range in [2.0m/s2, 2.5m/s2], beyond the limit of comfort but within tolerable scope; as for subject C without application of clothoid, will exceed the limit of 1.0m/s3. So it is suggested using clothoid, considering improving the quality.

Driver Model Based on Controller with Open and Close Loop

2014 ◽  
Vol 889-890 ◽  
pp. 958-961
Author(s):  
Huan Ming Chen
Keyword(s):  
Closed Loop ◽  
Driver Model ◽  
Lateral Acceleration ◽  
Vehicle Model ◽  
Vehicle Handling ◽  
Loop Control ◽  
Driving Experience ◽  
Loop Feedback ◽  
Closed Loop Feedback ◽  
Target Path

It is very important to simulate driver's manipulation for people - car - road closed loop simulation system. In this paper, the driver model is divided into two parts, linear vehicle model is used to simulate the driver's driving experience, and closed-loop feedback is used to characterize the driver's emergency feedback. The lateral acceleration of vehicle is used as feedback in closed loop control. Simulation results show that the smaller lateral acceleration requires the less closed-loop feedback control. The driver model can accurately track the target path, which can be used to simulate the manipulation of the driver. The driver model can be used for people - car - road closed loop simulation to evaluate vehicle handling stability.

scholarly journals Optimisation of polynomial railway transition curves of even degrees

2015 ◽  
Vol 35 (3) ◽  
pp. 71-86 ◽  
Author(s):  
Krzysztof Zboiński ◽  
Piotr Woźnica
Keyword(s):  
Simulation Software ◽  
Lateral Acceleration ◽  
Vehicle Body ◽  
Railway Vehicle ◽  
Vehicle Model ◽  
Vehicle Simulation ◽  
Optimisation Methods ◽  
Advanced Model ◽  
Transition Curves

This paper represents new results obtained by its authors while searching for the proper shape of polynomial railway transition curves (TCs). The search for the proper shape means the evaluation of the curve properties based on chosen dynamical quantities and generation of such shape with use of mathematically understood optimisation methods. The studies presented now and in the past always had got a character of the numerical tests. For needs of this work advanced vehicle model, dynamical track-vehicle and vehicle-passenger interactions, and optimisation methods were exploited. In this software complete rail vehicle model of 2-axle freight car, the track discrete model, and non-linear description od wheel-rail contact are used. That part of the software, being vehicle simulation software, is combined with library optimisation procedures into the final computer programme. The main difference between this and previous papers by the authors are the degrees of examinated polynomials. Previously they tested polynomial curves of odd degrees, now they focus on TCs of 6th, 8th and 10th degrees with and without curvature and superelevation ramp tangence in the TC’s terminal points. Possibility to take account of fundamental demands (corresponding values of curvature in terminal points) concerning TC should be preserved. Results of optimisation are compared both among themselves and with 3rd degree parabola. The aim of present article is to find the polynomial TCs’ optimum shapes which are determined by the possible polynomial configurations. Only one dynamical quantities being the results of simulation of railway vehicle advanced model is exploited in the determination of quality function (QF1). This is: minimum of integral of vehicle body lateral acceleration.

Integration of Geometry and Analysis for the Study of Liquid Sloshing in Vehicle System Dynamics

2017 ◽  
Author(s):  
Brynne Nicolsen ◽  
Huailong Shi ◽  
Liang Wang ◽  
Ahmed A. Shabana
Keyword(s):  
Rigid Body ◽  
Vehicle Dynamics ◽  
Three Dimensional ◽  
Rigid Body Dynamics ◽  
Liquid Sloshing ◽  
Inertia Force ◽  
Vehicle Stability ◽  
Vehicle Model ◽  
Rail Vehicle ◽  
Curve Negotiation

Commonly-used sloshing models are either unable to capture changes in the continuous distribution of the fluid free surface, or are not suited for the integration with high fidelity computational multibody system (MBS) algorithms. The objective of this investigation is to address this deficiency by developing a new continuum-based liquid sloshing approach that accounts for the effect of complex fluid and tank geometry and can be systematically integrated with MBS algorithms in order to allow for studying complex motion scenarios. A unified geometry/analysis mesh is used from the outset to examine the effect of liquid sloshing on railroad and highway vehicle dynamics during various maneuvers including braking and curve negotiation [1,2]. Using a non-modal approach, the geometry of the tank and fluid is accurately defined, a continuum-based fluid constitutive model is developed, and a fluid-tank contact algorithm using the penalty approach is employed. In order to examine the effect of liquid sloshing on vehicle dynamics during curve negotiation, a general and precise definition of the outward inertia force is defined, which for flexible bodies does not take the simple form used in rigid body dynamics. During maneuvers, the liquid may experience large displacements and significant changes in shape that can be captured effectively using absolute nodal coordinate formulation (ANCF) finite elements. For rail systems, the liquid sloshing model is integrated with a three-dimensional MBS vehicle algorithm, in which the three-dimensional wheel/rail contact force formulation is used to account for the longitudinal, lateral, and spin creep forces that influence vehicle stability. The effects of fluid sloshing on vehicle dynamics in the case of a tank partially filled with liquid are studied and compared with the equivalent rigid body model in braking and curve negotiation. The results obtained in the study of the rail vehicle model show that liquid sloshing can exacerbate the unbalance effects when the rail vehicle negotiates a curve at a velocity higher than the balance speed, and can significantly increase coupler forces during braking. Analysis of the highway vehicle model shows that the liquid sloshing changes the contact forces between the tires and the ground — increasing the forces on certain wheels and decreasing the forces on other wheels — which in cases of extreme sloshing, can negatively impact the vehicle stability by increasing the possibility of wheel lift and vehicle rollover.

Directional Response of a B-Train Vehicle Combination Carrying Liquid Cargo

1993 ◽  
Vol 115 (1) ◽  
pp. 133-139 ◽  
Author(s):  
R. Ranganathan ◽  
S. Rakheja ◽  
S. Sankar
Keyword(s):  
Free Surface ◽  
Three Dimensional ◽  
Lateral Acceleration ◽  
Flow Conditions ◽  
Vehicle Model ◽  
Liquid Motion ◽  
Directional Response ◽  
Response Characteristics ◽  
Weight Density ◽  
Liquid Movement

Directional dynamics of a B-train tank vehicle is investigated by integrating the three-dimensional vehicle model to the dynamics associated with the movement of free surface of liquid within the partially filled tanks. The motion of the free surface of liquid due to instantaneous tank roll and lateral acceleration is computed assuming steady state fluid flow conditions. The influence of liquid motion on the dynamic response of the rearmost trailer is investigated for both constant and transient steer inputs, assuming constant forward speed. Directional response characteristics of the B-train tank vehicle are compared to those of an equivalent rigid cargo vehicle to demonstrate the destabilizing effects of the liquid movement within the tank vehicle. Directional response characteristics are further discussed for variation in weight density of liquid and thus the fill height, while the axle loads are held constant around maximum permissible values.

Adapting an Articulated Vehicle to the Drivers

1999 ◽  
Author(s):  
Xiaobo Yang ◽  
Subhash Rakheja ◽  
Ion Stiharu
Keyword(s):  
Open Loop ◽  
Roll Angle ◽  
Driver Model ◽  
Lateral Acceleration ◽  
Vehicle Model ◽  
Response Characteristics ◽  
Performance Potentials ◽  
Compensatory Gain ◽  
Steering Effort ◽  
Control Limits

Abstract A yaw plane model with limited roll DOF of a five-axle tractor semitrailer is developed to study the open-loop directional dynamics of the vehicle. A comprehensive driver model incorporating path preview, low and high frequency compensatory gains and time delays, and prediction of tractor lateral acceleration, articulation rate of the combination and the trailer sprung mass roll angle is developed and integrated with the vehicle model. The coupled driver-vehicle model is analyzed to explore the performance potentials of the vehicle design adapted for control limits of the driver. The data reported in the published studies are reviewed to identify range of control limits of the drivers in terms of preview distance, reaction time and compensatory gain. A comprehensive performance index including the path tracking, vehicle dynamic response characteristics and the driver’s steering effort is formulated and minimized using Gauss-Newton method to derive the desirable ranges of the vehicle parameters, including geometric, inertial, suspension, tire and the fifth wheel. The results of the study revealed that a driver with higher skill can easily adapt the vehicle with large size, soft suspension and relative over-steer nature. The adaptability of the vehicle is further examined for different drivers with varying skills. It is concluded that the adaptability and thus the directional performance of the vehicle can be enhanced through variations in the weights and dimensions, and suspension, tire and the fifth wheel properties. The results further show that the driver-adapted vehicle yields up to 33% reduction in the steering effort demand posed on the driver, while the roll angle and yaw rate response decrease by up to 40%.

Establishing design guidelines for compound horizontal curves on three-dimensional alignments

2005 ◽  
Vol 32 (4) ◽  
pp. 615-626 ◽  
Author(s):  
Said Easa ◽  
Essam Dabbour
Keyword(s):  
Three Dimensional ◽  
Design Guidelines ◽  
Simulation Software ◽  
Lateral Acceleration ◽  
Vertical Alignment ◽  
Vehicle Simulation ◽  
Minimum Radius ◽  
Horizontal Curves ◽  
Flat Terrain ◽  
Current Design

In current design guides, the minimum radii of compound horizontal curves are based on the design requirements of simple horizontal curves for each arc on flat terrain. Such a design ignores the effects of compound curvature and vertical alignment. This paper uses computer simulation software to establish the minimum radius requirements for compound curves, considering these effects. The actual lateral acceleration experienced by a vehicle negotiating a two-dimensional (2-D) simple curve is recorded as a base scenario to facilitate the analysis of a compound curve on a flat terrain or combined with vertical alignment (three-dimensional (3-D) compound curves). The vertical alignments examined include upgrades, downgrades, crest curves, and sag curves. Mathematical models for minimum radius requirements were developed for flat and 3-D compound curves. Three types of design vehicles were used. The results show that an increase in the minimum radius ranging from 5% to 26% is required to compensate for the effects of both compound curvature and vertical alignment.Key words: highway geometric design, compound horizontal alignments, side friction, vehicle simulation, 3-D alignments.

scholarly journals 3D IMAGING OF INDIVIDUAL PARTICLES: A REVIEW

2012 ◽  
Vol 31 (2) ◽  
pp. 65 ◽  
Author(s):  
Eric Pirard
Keyword(s):  
Literature Review ◽  
Digital Imaging ◽  
Systems Analysis ◽  
3D Imaging ◽  
Materials Science ◽  
Recent Literature ◽  
Three Dimensional ◽  
Shape Estimation ◽  
Individual Particles ◽  
Made In

In recent years, impressive progress has been made in digital imaging and in particular in three dimensional visualisation and analysis of objects. This paper reviews the most recent literature on three dimensional imaging with a special attention to particulate systems analysis. After an introduction recalling some important concepts in spatial sampling and digital imaging, the paper reviews a series of techniques with a clear distinction between the surfometric and volumetric principles. The literature review is as broad as possible covering materials science as well as biology while keeping an eye on emerging technologies in optics and physics. The paper should be of interest to any scientist trying to picture particles in 3D with the best possible resolution for accurate size and shape estimation. Though techniques are adequate for nanoscopic and microscopic particles, no special size limit has been considered while compiling the review.

Numerical Study on the Effect of Inner Tube Position on Heat Transfer Process in Self-Recuperative Radiant Tube

2011 ◽  
Vol 228-229 ◽  
pp. 676-680 ◽  
Author(s):  
Ye Tian ◽  
Xun Liang Liu ◽  
Zhi Wen
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Numerical Study ◽  
Flame Temperature ◽  
Three Dimensional ◽  
Mathematic Model ◽  
Heat Transfer Process ◽  
Bulk Temperature ◽  
Radiant Tube ◽  
Peak Value

A three-dimensional mathematic model is developed for a 100kw single-end recuperative radiant tube and the simulation is performed with the CFD software FLUENT. Also it is used to investigate the effect of distance between combustion chamber exit and inner tube on heat transfer process. The results suggest that the peak value of combustion flame temperature drops along with the increasing of distance, which leads to low NOX discharging. Also radiant tube surface bulk temperature decreases, which causes radiant tube heating performance losses.

Truck Suspension Design to Minimize Road Damage

1996 ◽  
Vol 210 (2) ◽  
pp. 95-107 ◽  
Author(s):  
D J Cole ◽  
D Cebon
Keyword(s):  
Three Dimensional ◽  
Fourth Power ◽  
Vehicle Model ◽  
Efficient Procedure ◽  
Suspension Parameters ◽  
Articulated Vehicle ◽  
Suspension Stiffness ◽  
Optimal Values ◽  
Dynamic Components ◽  
Stiffness And Damping

The objective of the work described in this paper is to establish guidelines for the design of passive suspensions that cause minimum road damage. An efficient procedure for calculating a realistic measure of road damage (the 95th percentile aggregate fourth power force) in the frequency domain is derived. Simple models of truck vibration are then used to examine the influence of suspension parameters on this road damage criterion and to select optimal values. It is found that to minimize road damage a suspension should have stiffness about one fifth of current air suspensions and damping up to twice that typically provided. The use of an anti-roll bar allows a high roll-over threshold without increasing road damage. It is thought that optimization in the pitch-plane should exclude correlation between the axles, to ensure that the optimized suspension parameters are robust to payload and speed changes. A three-dimensional ‘whole-vehicle’ model of an air suspended articulated vehicle is validated against measured tyre force histories. Optimizing the suspension stiffness and damping results in a 5.8 per cent reduction in road damage by the whole vehicle (averaged over three speeds). This compares with a 40 per cent reduction if the dynamic components of the tyre forces are eliminated completely.

Measurement of Angular Acceleration of a Rigid Body Using Linear Accelerometers

1975 ◽  
Vol 42 (3) ◽  
pp. 552-556 ◽  
Author(s):  
A. J. Padgaonkar ◽  
K. W. Krieger ◽  
A. I. King
Keyword(s):  
Experimental Data ◽  
Rigid Body ◽  
Simple Procedure ◽  
Three Dimensional ◽  
Angular Acceleration ◽  
Theory And Practice ◽  
Body Segments ◽  
Impact Biomechanics ◽  
The Stability ◽  
Definition Of

The computation of angular acceleration of a rigid body from measured linear accelerations is a simple procedure, based on well-known kinematic principles. It can be shown that, in theory, a minimum of six linear accelerometers are required for a complete definition of the kinematics of a rigid body. However, recent attempts in impact biomechanics to determine general three-dimensional motion of body segments were unsuccessful when only six accelerometers were used. This paper demonstrates the cause for this inconsistency between theory and practice and specifies the conditions under which the method fails. In addition, an alternate method based on a special nine-accelerometer configuration is proposed. The stability and superiority of this approach are shown by the use of hypothetical as well as experimental data.

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