The Use of Accident Data in Studying Vehicle Handling Performance

1975 ◽  
Vol 189 (1) ◽  
pp. 243-258 ◽  
Author(s):  
I. S. Jones
Keyword(s):  
Weight Ratio ◽  
Control Measures ◽  
Lateral Acceleration ◽  
Loss Of Control ◽  
Accident Rate ◽  
Vehicle Handling ◽  
Handling Performance ◽  
Handling Characteristics ◽  
Accident Causation ◽  
Accident Data

A study to establish the relation between vehicle handling performance and accident causation. Since deficiencies in handling are likely to be associated with accidents involving loss of control, measures of handling which are likely to express proneness to loss of control are first suggested; emphasis is placed on simplicity of measurement to allow as many different models of car as possible to be included in the study. Accident rates for the various types of accident which are likely to be influenced by these parameters are then determined by model of car. The effect of other factors, such as variation in driver characteristics between different models of car on these rates is then assessed so that the relation between handling characteristics and accident frequency can be defined. Finally, the relative importance of the various measures of handling suggested are assessed. The results suggest that there is a definite relation between handling performance and accident causation although it is relatively small when compared to driver effects. In explaining the variation in the accident rate between different models of car, driver effects account for as much as 70 per cent; if driver effects are removed from the accident rate then handling parameters explain between 35 and 40 per cent of the remaining variation between models of car. The important parameters appear to be weight, a measure of the change in understeer as a function of lateral acceleration and power to weight ratio.

Mechanism for the Reduction of Lateral Friction Capabilities of a Delaminated Tire

2012 ◽  
Author(s):  
Paul T. Semones ◽  
David A. Renfroe ◽  
H. Alex Roberts ◽  
Don Y. Lee
Keyword(s):  
Coefficient Of Friction ◽  
Test Procedure ◽  
Lateral Acceleration ◽  
Test Vehicle ◽  
Vehicle Handling ◽  
Passenger Vehicles ◽  
Handling Characteristics ◽  
Structural Rigidity ◽  
Vehicle Testing ◽  
Lateral Friction

Tire delamination is a significant vehicle dynamics safety problem contributing to the loss of control of passenger vehicles, often resulting in accidents and injuries. This paper examines vehicle handling characteristics after a complete outer tread belt separation on 2-steel belt and 3-steel belt tires. The test vehicle used to examine this phenomenon was a Ford 15-passenger van. The test procedure was the SAE J266 circle test, and the measure of effectiveness was taken to be the lateral acceleration at which the vehicle transitioned to an oversteer characteristic. For a typical tread separation on a 2-steel belted tire, the tire loses one of its steel belts and thus much of its structural rigidity. Vehicle testing using a 3-steel belted tire, in which only the outermost single belt was removed, and the remaining two belts were oriented along opposite diagonals, showed that the vehicle remained in an understeer condition at higher lateral accelerations than with the 2-steel belted tire, indicating that the retention of greater structural rigidity to the impaired tire resulted in it maintaining much of its cornering stiffness. Until now, it has been assumed that the reduction in cornering stiffness of a delaminated tire was predominately due to the low coefficient of friction of the exposed steel belt after delamination. The testing described in this paper suggests that a significant influence on the remaining cornering stiffness of the tire after tread separation is the overall remaining structural rigidity of the tire. From this testing, it is theorized that the rigidity of the delaminated tire is at least as important as the reduced coefficient of friction for the purposes of maintaining vehicle understeer behavior after a delamination.

scholarly journals Detection and analysis of hazardous locations on roads: a case study of the Croatian motorway A1

Transport ◽  
2017 ◽  
Vol 33 (2) ◽  
pp. 418-428
Author(s):  
Dražen Cvitanić ◽  
Biljana Vukoje
Keyword(s):  
Sudden Change ◽  
Design Guidelines ◽  
Lateral Acceleration ◽  
Driver Behaviour ◽  
Vehicle Handling ◽  
Vehicle Accidents ◽  
Vehicle Accident ◽  
Handling Characteristics ◽  
Bicycle Model ◽  
Single Vehicle

The present paper describes research undertaken to identify causes underlying single-vehicle accidents (in terms of road design, driver behaviour and vehicle handling characteristics), which continuously happen in one specific section of Croatian motorway A1. The research resulted in a proposed procedure for a detection of hazardous locations on motorways and analysis of possible causes of single-vehicle accidents. The main part of the procedure involves test-rides with a vehicle equipped with devices (a ball bank indicator and a GPS data logger), which collect data on driver’s behaviour and vehicle handling characteristics (position, speed, longitudinal and lateral acceleration, heading, path radius, etc.). Despite the fact that the motorway was designed in accordance with the design guidelines, test rides performed by higher operating speeds identified two locations with a lateral acceleration change a few times higher than the design value. The collected data are then used for analysing hypotheses about the possible causes of accidents by using a vehicle dynamic model. The hypothesis that a sudden change in lateral acceleration could result in a driver’s inadequate manoeuvre like braking and cause a vehicle accident was analysed with a transient bicycle model. The results of test rides and the transient bicycle model indicate that speed, intensity of deceleration and underinflated tires significantly affect the probability of a single-vehicle accident.

Enhancement of vehicle handling characteristics by suspension kinematic control

2001 ◽  
Vol 215 (2) ◽  
pp. 197-216 ◽  
Author(s):  
S H Lee ◽  
U K Lee ◽  
C S Han
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Lateral Acceleration ◽  
Vehicle Body ◽  
Control Input ◽  
Vehicle Handling ◽  
Kinematic Control ◽  
Front Suspension ◽  
Handling Characteristics ◽  
Suspension Geometry

In this paper, the enhancement of vehicle handling characteristics through the active kinematic control system (AKCS) is investigated. AKCS can improve the stability and ride comfort of a vehicle by automatically controlling suspension geometry in accordance with the running conditions of a vehicle. The variable roll centre suspension concept in a McPherson strut suspension is proposed, and lateral acceleration feedback control is derived to calculate the control input. The independent rear wheel steering system, which controls both rear wheels independently and actively, is also proposed. To achieve this, three suggested positions for controlling the suspension geometry are considered. The first position is between the mounting point of the lower arm of a McPherson front suspension and the vehicle body. The second position is between the mounting point of the strut and the vehicle body. The third position is between the mounting point of the lateral link of the multilink rear suspension and the vehicle body. In order to evaluate the handling performance, a 15 degrees of freedom full vehicle model is constructed using the commercial multibody analysis program ADAMS. The control inputs for integrated control of the front and rear suspensions are defined, and roll centre migration and vehicle behaviour are investigated. In step steering and double lane change manoeuvres, the simulation results demonstrate that integrated kinematic control can adjust the roll centre migration, by which the handling characteristics of the AKCS vehicle such as roll angle, lateral acceleration and yaw rate are much improved.

Handling and driving characteristics for six-wheeled vehicles

2000 ◽  
Vol 214 (2) ◽  
pp. 159-170 ◽  
Author(s):  
K Huh ◽  
J Kim ◽  
J Hong
Keyword(s):  
Relevant Literature ◽  
Lateral Acceleration ◽  
Control Law ◽  
Simulation Tool ◽  
Sideslip Angle ◽  
Handling Performance ◽  
The Road ◽  
Handling Characteristics ◽  
Simulation Results ◽  
Wheeled Vehicles

Handling performance of six-wheeled special-purpose vehicles is investigated in this study. Six-wheel drive (6WD) vehicles are believed to have good performance in off-the-road manoeuvring and to have fail-safe capabilities when one or two of their tyres are blown. However, the handling performance of six-wheel steering (6WS) vehicles is not yet well understood in the relevant literature. In this paper, six-wheeled vehicles are modelled as an 18 degree-of-freedom (DOF) system that considers non-linear vehicle dynamics, tyre models and kinematic effects. The vehicle model is constructed into a simulation tool using MATLAB/SIMULINK so that input/output and vehicle parameters can be changed easily using the modulated approach. Handling performance is analysed not only from the frequency domain but also from the time domain. Simulation results demonstrate that the effect of middle-wheel steering is not negligible from the viewpoint of handling characteristics such as yaw rate, lateral acceleration, etc. The simulation tool is also utilized for the manoeuvring analysis over a rough rigid surface, where the separation between the wheels and the road can be considered. In addition, a new 6WS control law is proposed in order to minimize the sideslip angle. Lane change simulation results show the advantage of 6WS vehicles with the proposed control law.

A suspension system with a variable roll centre for the improvement of vehicle handling characteristics

2001 ◽  
Vol 215 (6) ◽  
pp. 677-696 ◽  
Author(s):  
U Lee ◽  
C Han
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Suspension System ◽  
Lateral Acceleration ◽  
Vehicle Body ◽  
Control Input ◽  
Vehicle Handling ◽  
Body Side ◽  
Handling Characteristics ◽  
Suspension Geometry

In this paper, the improvement of vehicle handling characteristics using variable roll centre suspension (VRCS) is investigated. A vehicle with VRCS can improve stability and ride comfort by automatically controlling suspension geometry in accordance with the running conditions of the vehicle. To achieve this, a variable roll centre concept in the McPherson strut suspension system is suggested, while the two parts most sensitive for controlling the roll centre are suggested. One is between the vehicle body-side connecting portion of the lower arm and the vehicle body (control input, LCZ), and the other is between the vehicle body-side connecting portion of the strut and the vehicle body (control input, STY). Kinematic roll centre analysis, based on the analytic half-car model, shows that the use of two control inputs, LCZ and STY, can decrease migration of the roll centre and centre of gravity according to the side force. In order to quantify the relationship between roll centre and geometry control input and evaluate handling performance, a full vehicle model of 15 degrees of freedom (DOF) is constructed using multi-body dynamic analysis software, ADAMS. In step steering and double lane change manoeuvres, simulation results demonstrate that a vehicle with VRCS adjusts roll centre migration, and handling characteristics such as roll angle, lateral acceleration and yaw rate are much improved.

A comparison of different models of passive seat suspensions

2021 ◽  
pp. 095440702199092
Author(s):  
Raj Desai ◽  
Anirban Guha ◽  
P. Seshu
Keyword(s):  
Human Body ◽  
Separate Analysis ◽  
Vehicle Model ◽  
Human Body Model ◽  
Human Comfort ◽  
Vehicle Handling ◽  
Seat Suspension ◽  
Handling Characteristics ◽  
Suspension Model ◽  
Suspension Models

Long duration exposure to vehicle induced vibration causes various ailments to humans. Amongst the various components of the human-vehicle system, the seat suspension plays a major role in determining the level of vibration transferred to humans. However, optimising the suspension for maximising human comfort leads to poor vehicle handling characteristics. Thus, predicting human comfort through various seat suspension models is a widely researched topic. However, the appropriate seat suspension model to be used has not been identified so far. Neither has any prior work reported integrating models of all the components necessary for this analysis, namely human body, cushion, seat suspension and vehicle chassis, each with the appropriate level of complexity. This work uses a two-dimensional 12 DoF seated human body model with inclined backrest support, a nonlinear cushion model, a seat suspension model and a full vehicle model. Two kinds of road profiles – one with random roughness and one with a bump – have been used. It then compares the performance of five different seat suspension models based on a number of human comfort related parameters (seat to head transmissibility, suspension travel, seat acceleration, cushion contact force and head acceleration in both vertical and fore-aft directions) and vehicle handling parameters (vertical, rolling and pitching acceleration of chassis). The results clearly show the superiority of the configuration which involves a spring parallel to an inclined multi-stage damper. A separate analysis was also done to judge whether the integration of the vehicle model (with its associated complication) was necessary for this analysis. A comparison of the human body’s internal forces, moments, acceleration, and absorbed power with and without the vehicle model clearly indicates the need of using the former.

Assessment of tolerance for reducing yield losses in field pea caused by Aphanomyces root rot

2013 ◽  
Vol 93 (3) ◽  
pp. 473-482 ◽  
Author(s):  
R. L. Conner ◽  
K. F. Chang ◽  
S. F. Hwang ◽  
T. D. Warkentin ◽  
K. B. McRae
Keyword(s):  
Disease Severity ◽  
Root Rot ◽  
Weight Ratio ◽  
Field Pea ◽  
Control Measures ◽  
Effective Control ◽  
Yield Losses ◽  
Plant Vigour ◽  
Shoot Weight ◽  
High Yields

Conner, R. L., Chang, K. F., Hwang, S. F., Warkentin, T. D. and McRae, K. B. 2013. Assessment of tolerance for reducing yield losses in field pea caused by Aphanomyces root rot. Can. J. Plant Sci. 93: 473–482. Aphanomyces root rot, caused by Aphanomyces euteiches Drechs., is a serious disease of peas (Pisum sativum) that can severely reduce seed yield, and few effective control measures are available. The development of pea cultivars with tolerance or partial resistance to Aphanomyces root rot is generally considered to be one of the best options to reduce yield loss. A 4-yr field study was conducted at disease-free sites and at an Aphanomyces root rot site to compare the responses of cultivars and lines in the presence and absence of Aphanomyces root rot, identify breeding lines with tolerance and to evaluate the effects of tolerance on plant growth, disease severity and yield. At the Aphanomyces root rot site, a second test was established in which the phosphite fungicide Phostrol™ was applied as a soil drench treatment to the pea cultivars and lines. Aphanomyces root rot reduced seedling emergence, biomass production and yield in the susceptible pea genotypes. However, line 00-2067 consistently produced relatively high yields at all the field sites. At the Aphanomyces root rot site, yield was closely associated with plant vigour and shoot weight. Small, but significant, differences (P<0.05) in disease severity were observed between susceptible cultivars and tolerant lines indicating that the lines producing high yields at the Aphanomyces root rot site are tolerant rather than partially resistant. The root/shoot weight ratio was very low in the tolerant lines, indicating that even though their root systems were reduced and severely damaged by root rot, they were still able to produce high yields under favourable conditions for the disease. Drench application of the fungicide Phostrol™ did not significantly reduce root rot severity or improve the performance of any of the pea cultivars or lines.

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 Vehicle Cornering Performance Evaluation and Enhancement Based on CAE and Experimental Analyses

2019 ◽  
Vol 9 (24) ◽  
pp. 5428
Author(s):  
Hsing-Hui Huang ◽  
Ming-Jiang Tsai
Keyword(s):  
Steady State ◽  
Suspension System ◽  
Lateral Acceleration ◽  
Phase Lag ◽  
Handling Performance ◽  
Yaw Rate ◽  
Full Vehicle ◽  
Camber Angle ◽  
Simulation Results ◽  
Initial Camber

A full-vehicle analysis model was constructed incorporating a SLA (Short Long Arm) strut front suspension system and a multi-link rear suspension system. CAE (Computer Aided Engineering) simulations were then performed to investigate the lateral acceleration, yaw rate, roll rate, and steering wheel angle of the vehicle during constant radius cornering tests. The validity of the simulation results was confirmed by comparing the computed value of the understeer coefficient (Kus) with the experimental value. The validated model was then used to investigate the steady-state cornering performance of the vehicle (i.e., the roll gradient and yaw rate gain) at various speeds. The transient response of the vehicle was then examined by means of simulated impulse steering tests. The simulation results were confirmed by comparing the calculated values of the phase lag, natural frequency, yaw rate gain rate, and damping ratio at various speeds with the experimental results. A final series of experiments was then performed to evaluate the relative effects of the cornering stiffness, initial toe-in angle, and initial camber angle on the steady-state and transient-state full-vehicle cornering handling performance. The results show that the handling performance can be improved by increasing the cornering stiffness and initial toe-in angle or reducing the initial camber angle.

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