Tire Friction on Wet Roads

1976 ◽  
Vol 49 (3) ◽  
pp. 862-908 ◽  
Author(s):  
K. A. Grosch ◽  
A. Schallamach
Keyword(s):  
Hydrodynamic Lubrication ◽  
Vehicle Control ◽  
Critical Conditions ◽  
Frictional Properties ◽  
Road Surfaces ◽  
Road Friction ◽  
Tire Forces ◽  
The One ◽  
Tire Friction ◽  
Contact Pressures

Abstract Evidence accumulates that tire forces on wet roads, particularly when the wheel is locked, are determined by the dry frictional properties of the rubber on the one hand and by hydrodynamic lubrication in the contact area on the other. The probable reason why they are so clearly separable is that water is a poor lubricant, tending to separate into globules and dry areas under relatively small pressures. Road surfaces and tire profiles are, therefore, designed to create easy drainage and high local contact pressures. The influence of road friction on vehicle control well below the critical conditions is becoming more clearly understood; but more Investigations are required here, in particular under dynamic conditions.

Adaptive Unified Monitoring System Design for Tire-Road Information

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Shuo Cheng ◽  
Ming-ming Mei ◽  
Xu Ran ◽  
Liang Li ◽  
Lin Zhao
Keyword(s):  
Friction Coefficient ◽  
Monitoring System ◽  
Estimation Method ◽  
Recursive Least Squares ◽  
Vehicle Body ◽  
Friction Forces ◽  
Road Friction ◽  
Tire Forces ◽  
Tire Friction ◽  
Road Friction Coefficient

Knowledge of the tire-road information is not only very crucial in many active safety applications but also significant for self-driving cars. The tire-road information mainly consists of tire-road friction coefficient and road-tire friction forces. However, precise measurement of tire-road friction coefficient and tire forces requires expensive equipment. Therefore, the monitoring of tire-road information utilizing either accurate models or improved estimation algorithms is essential. Considering easy availability and good economy, this paper proposes a novel adaptive unified monitoring system (AUMS) to simultaneously observe the tire-road friction coefficient and tire forces, i.e., vertical, longitudinal, and lateral tire forces. First, the vertical tire forces can be calculated considering vehicle body roll and load transfer. The longitudinal and lateral tire forces are estimated by an adaptive unified sliding mode observer (AUSMO). Then, the road-tire friction coefficient is observed through the designed mode-switch observer (MSO). The designed MSO contains two modes: when the vehicle is under driving or brake, a slip slope method (SSM) is used, and a recursive least-squares (RLS) identification method is utilized in the SSM; when the vehicle is under steering, a comprehensive friction estimation method is adopted. The performance of the proposed AUMS is verified by both the matlab/simulinkCarSim co-simulation and the real car experiment. The results demonstrate the effectiveness of the proposed AUMS to provide accurate monitoring of tire-road information.

A Modified Dugoff Tire Model for Combined-slip Forces

2010 ◽  
Vol 38 (3) ◽  
pp. 228-244 ◽  
Author(s):  
Nenggen Ding ◽  
Saied Taheri
Keyword(s):  
Vehicle Dynamics ◽  
Tire Model ◽  
Magic Formula ◽  
Model Based ◽  
Proposed Model ◽  
Road Friction ◽  
On Line ◽  
Double Lane Change ◽  
Tire Forces ◽  
Tire Models

Abstract Easy-to-use tire models for vehicle dynamics have been persistently studied for such applications as control design and model-based on-line estimation. This paper proposes a modified combined-slip tire model based on Dugoff tire. The proposed model takes emphasis on less time consumption for calculation and uses a minimum set of parameters to express tire forces. Modification of Dugoff tire model is made on two aspects: one is taking different tire/road friction coefficients for different magnitudes of slip and the other is employing the concept of friction ellipse. The proposed model is evaluated by comparison with the LuGre tire model. Although there are some discrepancies between the two models, the proposed combined-slip model is generally acceptable due to its simplicity and easiness to use. Extracting parameters from the coefficients of a Magic Formula tire model based on measured tire data, the proposed model is further evaluated by conducting a double lane change maneuver, and simulation results show that the trajectory using the proposed tire model is closer to that using the Magic Formula tire model than Dugoff tire model.

Calculation of Dynamic Tire Forces from Aircraft Instrumentation Data

2010 ◽  
Vol 38 (3) ◽  
pp. 182-193 ◽  
Author(s):  
Gary E. McKay
Keyword(s):  
System Performance ◽  
Equations Of Motion ◽  
Test Laboratory ◽  
Excellent Correlation ◽  
Friction Behavior ◽  
Aircraft Landing ◽  
Data Scatter ◽  
Tire Forces ◽  
Six Degree Of Freedom ◽  
Tire Friction

Abstract When evaluating aircraft brake control system performance, it is difficult to overstate the importance of understanding dynamic tire forces—especially those related to tire friction behavior. As important as they are, however, these dynamic tire forces cannot be easily or reliably measured. To fill this need, an analytical approach has been developed to determine instantaneous tire forces during aircraft landing, braking and taxi operations. The approach involves using aircraft instrumentation data to determine forces (other than tire forces), moments, and accelerations acting on the aircraft. Inserting these values into the aircraft’s six degree-of-freedom equations-of-motion allows solution for the tire forces. While there are significant challenges associated with this approach, results to date have exceeded expectations in terms of fidelity, consistency, and data scatter. The results show excellent correlation to tests conducted in a tire test laboratory. And, while the results generally follow accepted tire friction theories, there are noteworthy differences.

scholarly journals Pedestrian-Vehicle Accidents Reconstruction with PC-Crash®: Sensibility Analysis of Factors Variation

2016 ◽  
Author(s):  
Francisco Martínez Gala
Keyword(s):  
Real World ◽  
Software Tool ◽  
Reconstruction Process ◽  
Vehicle Accidents ◽  
Projection Distance ◽  
Road Friction ◽  
Pedestrian Accidents ◽  
Sensibility Analysis ◽  
The One ◽  
Full Factorial

This paper describes the main findings of a study performed by INSIA-UPM about the improvement of the reconstruction process of real world vehicle-pedestrian accidents using PC-Crash® software, aimed to develop a software tool for the estimation of the variability of the collision speed due to the lack of real values of some parameters required during the reconstruction task. The methodology has been based on a sensibility analysis of the factors variation. A total of 9 factors have been analyzed with the objective of identifying which ones were significant. Four of them (pedestrian height, collision angle, hood height and pedestrian-road friction coefficient) were significant and were included in a full factorial experiment with the collision speed as an additional factor in order to obtain a regression model with up to third level interactions. Two different factorial experiments with the same structure have been performed because of pedestrian gender differences. The tool has been created as a collision speed predictor based on the regression models obtained, using the 4 significant factors and the projection distance measured or estimated in the accident site. The tool has been used on the analysis of real-world reconstructed accidents occurred in the city of Madrid (Spain). The results have been adequate in most cases with less than 10% of deviation between the predicted speed and the one estimated in the reconstructions.DOI: http://dx.doi.org/10.4995/CIT2016.2016.3467

CHARACTERIZATION OF ROAD PROFILES BASED ON FRACTAL PROPERTIES AND CONTACT MECHANICS

2017 ◽  
Vol 90 (2) ◽  
pp. 405-427 ◽  
Author(s):  
Mehran Motamedi ◽  
Saied Taheri ◽  
Corina Sandu ◽  
Pierrick Legrand
Keyword(s):  
Contact Theory ◽  
The Road ◽  
Frictional Properties ◽  
Wet Friction ◽  
Fractal Properties ◽  
Fractal Parameters ◽  
Road Surfaces ◽  
Friction Measurements ◽  
Friction Prediction

ABSTRACT A major challenge in tire and road engineering is to understand the intricate mechanisms of friction. Pavement texture is a feature of the road surface that determines most tire–road interactions, and it can be grouped into two classes of macro-texture and micro-texture. Since the effects of micro-texture and macro-texture dominate the friction measurements at low and high slip speeds, they can help provide sufficient resistance to skidding, if maintained at high levels. A non-contact profilometer is used to measure the macro- and micro-texture of several different road surfaces. The friction number for each surface is measured using the Michigan Department of Transportation's (MDOT) single axle friction trailer. Some fractal parameters of the measured profiles are estimated, and it is proved that all measured profiles display strong fractal behavior. The correlation between texture and fractal parameters and friction is investigated. It is shown that while global fractal quantities fail to classify pavement profiles, the pointwise Hölder exponent as a local fractal parameter, and also the mean square roughness, can discriminate profiles that have different frictional properties. For five road surfaces, two-dimensional (2D) characterization is done using one-dimensional (1D) profile measurements. The hysteretic coefficient of friction is estimated using the contact theory developed by B.N.J. Persson. Good correlation is observed between the wet friction measurements and friction prediction results.

Critical Conditions for Hydrodynamic Lubrication of Porous Metal Bearings

1962 ◽  
Vol 176 (1) ◽  
pp. 761-770 ◽  
Author(s):  
◽  
A. Cameron ◽  
V. T. Morgan ◽  
A. E. Stainsby
Keyword(s):  
Hydrodynamic Lubrication ◽  
Porous Metal ◽  
Critical Conditions

Fundamental studies on a temperature adaptable studded snow tire. Sliding frictional properties and reduced damage of road surfaces.

1987 ◽  
Vol 60 (6) ◽  
pp. 336-344
Author(s):  
Yoshitaka UCHIYAMA ◽  
Toshio MASHITA ◽  
Toshio OCHIAI ◽  
Asahiro AHAGON ◽  
Hiroshi HIRAKAWA
Keyword(s):  
Frictional Properties ◽  
Road Surfaces

Adaptive Vehicle Stability Control With Optimal Tire Force Allocation

2012 ◽  
Author(s):  
Mustafa Ali Arat ◽  
Kanwar Bharat Singh ◽  
Saied Taheri
Keyword(s):  
Stability Control ◽  
Crash Risk ◽  
Slip Angle ◽  
Vehicle Stability ◽  
Successful Implementation ◽  
Tire Force ◽  
Vehicle Stability Control ◽  
Saturation Region ◽  
Road Friction ◽  
Tire Forces

Vehicle stability control systems have been receiving increasing attention, especially over the past decade, owing to the advances in on-board electronics that enables successful implementation of complex algorithms. Another major reason for their increasing popularity lies in their effectiveness. Considering the studies that expose supporting results for reducing crash risk or fatality, organizations such as E.U. and NHTSA are taking steps to mandate the use of such safety systems on vehicles. The current technology has advanced in many aspects, and undoubtedly has improved vehicle stability as mentioned above; however there are still many areas of potential improvements. Especially being able to utilize information about tire-vehicle states (tire forces, tire-slip angle, and tire-road friction) would be significant due to the key role tires play in providing directional stability and control. This paper presents an adaptive vehicle stability controller that makes use of tire force and slip-angle information from an online tire monitoring system. Solving the optimality problem for the tire force allocation ensures that the control system does not push the tires into the saturation region where neither the driver nor the controller commands are implemented properly. The proposed control algorithm is implemented using MATLAB/CarSim® software packages. The performance of the system is evaluated under an evasive double lane change maneuver on high and low friction surfaces. The results indicate that the system can successfully stabilize the vehicle as well as adapting to the changes in surface conditions.

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