A Study on Asymmetries in Tire Forces

1978 ◽  
Vol 6 (2) ◽  
pp. 79-88
Author(s):  
E. Galli ◽  
R. Raggi
Keyword(s):  
Measuring Equipment ◽  
Lateral Force ◽  
Tire Force ◽  
Symmetry Properties ◽  
Tire Forces ◽  
Force Data ◽  
Spurious Signals

Abstract A formalism has been developed to analyze tire force data when asymmetries resulting from the intrinsic characteristics of the tires occur. Identifying and eliminating spurious signals from the measuring equipment has been found to be simple. The formalism is based on the decomposition of the force in independent terms, characterized by well-defined symmetry properties. As an application, lateral force asymmetries are analyzed. Further, the concepts of pseudocamber and pseudoslip are generalized to include slip angles different from zero.

Simultaneous Optimal Distribution of Lateral and Longitudinal Tire Forces for the Model Following Control

2004 ◽  
Vol 126 (4) ◽  
pp. 753-763 ◽  
Author(s):  
Ossama Mokhiamar ◽  
Masato Abe
Keyword(s):  
Lateral Force ◽  
Longitudinal Force ◽  
Equality Constraints ◽  
Steering Wheel ◽  
Slip Angle ◽  
Force Distribution ◽  
Distribution Method ◽  
Tire Force ◽  
Model Following Control ◽  
Tire Forces

This paper presents a proposed optimum tire force distribution method in order to optimize tire usage and find out how the tires should share longitudinal and lateral forces to achieve a target vehicle response under the assumption that all four wheels can be independently steered, driven, and braked. The inputs to the optimization process are the driver’s commands (steering wheel angle, accelerator pedal pressure, and foot brake pressure), while the outputs are lateral and longitudinal forces on all four wheels. Lateral and longitudinal tire forces cannot be chosen arbitrarily, they have to satisfy certain specified equality constraints. The equality constraints are related to the required total longitudinal force, total lateral force, and total yaw moment. The total lateral force and total moment required are introduced using the model responses of side-slip angle and yaw rate while the total longitudinal force is computed according to driver’s command (traction or braking). A computer simulation of a closed-loop driver-vehicle system subjected to evasive lane change with braking is used to prove the significant effects of the proposed optimal tire force distribution method on improving the limit handling performance. The robustness of the vehicle motion with the proposed control against the coefficient of friction variation as well as the effect of steering wheel angle amplitude is discussed.

Measurement of Steady State and Transient Aircraft Tire Forces

1975 ◽  
Vol 3 (2) ◽  
pp. 111-127 ◽  
Author(s):  
H. K. Brewer
Keyword(s):  
Steady State ◽  
Air Force ◽  
Tire Force ◽  
Aircraft Systems ◽  
Directional Control ◽  
Sample Data ◽  
Experimental Facilities ◽  
Air Force Base ◽  
Tire Forces ◽  
Force Data

Abstract Studies of aircraft directional control during takeoff and landing are best carried out with programmed simulators in which the pilot interacts directly with the aircraft systems. A vital input to such simulations is accurate tire force data, which at the present time are difficult to obtain because of lack of experimental facilities. This paper describes new test equipment for measuring aircraft tire forces which is now available at the Air Force Flight Dynamics Laboratory, Wright-Patterson Air Force Base. Sample data are presented and discussed which pertain to conventional and experimental radial ply aircraft tires.

A Universal Approach to Tire Forces Estimation by Accelerometer-Based Intelligent Tire: Analytical Model and Experimental Validation

2021 ◽  
Author(s):  
Guanqun Liang ◽  
Yan Wang ◽  
Mario A. Garcia ◽  
Tong Zhao ◽  
Zhe Liu ◽  
...  
Keyword(s):  
Analytical Model ◽  
Lateral Force ◽  
Lateral Acceleration ◽  
Beam Model ◽  
Vertical Force ◽  
Force Estimation ◽  
Tire Force ◽  
Universal Approach ◽  
Tire Force Estimation ◽  
Tire Forces

ABSTRACT Efforts to improve the performance and safety of vehicles include placing active sensing components (e.g., embedded microsensors) within tires result in intelligent tires. One application of intelligent tire is tire force estimation based on accelerometers. However, its development is limited due to the difficulty of relating the tire force to kinematical information by model-based theory. In this manuscript, a universal approach to tire forces estimation by the accelerometer-based intelligent tire is formulated and experimentally validated. First, a microelectromechanical system accelerometer-based intelligent tire prototype is established with the function of on-board monitoring of tire forces. Then, a theoretical rolling kinematics model is proposed for illustrating the mechanisms of acceleration fields, resulting from the coupling effect of rigid body motion and elastic deformation. An analytical model is formulated to estimate the vertical force in real time. Furthermore, the beam model is adopted to describe lateral deformations of the tire belt, directly linking lateral acceleration and lateral force. Finally, the lateral force can be estimated by lateral acceleration and vertical force already estimated. Based on a universal analytical model, the lateral force estimation method realizes high accuracy under different circumstances, even with unified coefficients, by clarifying and eliminating the influence of ply steer. A field test and two bench experiments have been conducted to fully validate the developed model. It can be concluded that the theoretical-analysis-based estimation model realizes an encouraging tire force estimation application with an intelligent tire hardware system.

Normalization of Tire Force and Moment Data

1993 ◽  
Vol 21 (2) ◽  
pp. 91-119 ◽  
Author(s):  
H. S. Radt ◽  
D. A. Glemming
Keyword(s):  
Surface Water ◽  
Lateral Force ◽  
Slip Angle ◽  
Inflation Pressure ◽  
Slip Ratio ◽  
Tire Force ◽  
Camber Angle ◽  
Potential Benefits ◽  
Overturning Moment ◽  
Semi Empirical

Abstract Semi-empirical theories of tire mechanics are employed to determine appropriate means to normalize forces, moments, angles, and slip ratios. Force and moment measurements on a P195/70R 14 tire were normalized to show that data at different loads could then be superimposed, yielding close to one normalized curve. Included are lateral force, self-aligning torque, and overturning moment as a function of slip angle, inclination angle, slip ratio, and combinations. It is shown that, by proper normalization of the data, one need only determine one normalized force function that applies to combinations of slip angle, camber angle, and load or slip angle, slip ratio, and load. Normalized curves are compared for the effects of inflation pressure and surface water thickness. Potential benefits as well as limitations and deficiencies of the approach are presented.

Tire Characteristics Estimation Method Independent of Road Surface Conditions

2018 ◽  
Vol 30 (1) ◽  
pp. 138-144 ◽  
Author(s):  
Yuuki Shiozawa ◽  
◽  
Hiroshi Mouri
Keyword(s):  
Estimation Method ◽  
Surface Friction ◽  
Road Surface ◽  
Force Estimation ◽  
Tire Force ◽  
Significant Difference ◽  
Vehicle Motion ◽  
Tire Force Estimation ◽  
Tire Forces ◽  
Force Characteristics

To control vehicle behavior, it is essential to estimate tire force accurately at all times. However, it is currently difficult to detect tire performance degradation before the deterioration of vehicle dynamics in real time because tire force estimation is usually conducted by comparing the observed vehicle motion with the onboard vehicle-model motion baseline reference. Such conventional estimators do not perform well if there is a significant difference between the vehicle and the model behavior. The lack of technology to easily predict tire forces and road surface friction is concerning. In this paper, a new tire state estimation method based on tire force characteristics is proposed.

Evaluation of Tire and Suspension Characteristics With 6-DOF Motion Platform

2007 ◽  
Author(s):  
Taichi Shiiba ◽  
Koichiro Yamato ◽  
Kensuke Kobayashi ◽  
Tsuyoshi Okada ◽  
Keisuke Morita
Keyword(s):  
Testing Machine ◽  
Load Condition ◽  
Vertical Displacement ◽  
Lateral Force ◽  
Individual Characteristics ◽  
Suspension System ◽  
Motion Platform ◽  
Tire Force ◽  
The Individual ◽  
Force Characteristics

An accurate description of the tire characteristics is very important for vehicle dynamic analysis. However, the characteristics of a tire are very complex, and it is not easy to develop the analytical model of tire force. It is also well known that the actual tire force is greatly affected by the suspension properties. The geometry of suspension arms determines the wheel alignment specifications such as toe and camber angle, and the stiffness and damping characteristics of suspension elements influences the vertical load of each wheel. In order to investigate the suspension properties upon the tire force characteristics, the authors have developed an original tire and suspension testing machine with 6-DOF motion platform. This system is equipped with a tire, a suspension system of a passenger car, a roller conveyer, and a 6-DOF motion platform. The developed system can evaluate the relationship between the suspension system and the tire, whereas the conventional tire testing machine measures the individual characteristics of a tire. In this paper, we report some test results with developed testing system. First, the lateral force characteristics of a tire in steady-state cornering condition were evaluated with this system, and the compliance steer characteristics of a suspension caused by the lateral force were also investigated at the same time. Next, the tire force characteristics were evaluated under the varying load condition. The random vertical displacement generated by the 6-DOF motion platform was applied to the tire, and the vertical and lateral force were observed. It was shown that the developed system can realize the evaluation of tire and suspension characteristics under various conditions.

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.

Relationship Between Tire Tread Physical Properties and Tire Force and Moment Properties

1989 ◽  
Vol 17 (2) ◽  
pp. 109-125 ◽  
Author(s):  
M. G. Pottinger ◽  
A. M. Fairlie
Keyword(s):  
Physical Properties ◽  
Lateral Force ◽  
Hysteresis Effect ◽  
Design Parameters ◽  
Slip Angle ◽  
Tire Force ◽  
Torque Curve ◽  
Driving Range ◽  
Important Design

Abstract Tire lateral force and aligning torque are the most significant determinants of automotive handling. Tread compound physical properties are important design parameters for determination of tire lateral force and aligning torque behavior. This paper extends the published knowledge of the effects of tread compound physical properties on force and moment to cover the entire range of slip angles encountered in driving. Below 10 degrees slip angle lateral force increases with increasing compound stiffness and hysteresis. At and above 10 degrees slip angle there is a change in the general trend. In this range it appears that an optimal compound stiffness exists and that the hysteresis effect reverses. Aligning torque shows two distinctly different behaviors. One, like that governing lateral force in the general driving range, is valid below the peak of the aligning torque curve. The other, valid above the peak of the aligning torque curve, shows decreasing aligning torque with increasing tread stiffness and no hysteresis effect.

Vehicle and Course Characterization Process for Indoor Tire Wear Simulation

2002 ◽  
Vol 30 (2) ◽  
pp. 100-121 ◽  
Author(s):  
D. O. Stalnaker ◽  
J. L. Turner
Keyword(s):  
Dynamic Load ◽  
Load Transfer ◽  
Longitudinal Velocity ◽  
Test Facility ◽  
Wear Rates ◽  
Tire Force ◽  
Tire Wear ◽  
Inclination Angles ◽  
Transfer Behavior ◽  
Tire Forces

Abstract An empirical methodology is described for separately characterizing vehicles and road courses for subsequent combination to predict tire force histories in tire use or testing. By building a library of vehicle and wear course characterizations, indoor wear test simulations can be selectively constructed by using any combination of “virtual” test vehicles and wear courses. A reliable transient record of vertical, lateral and fore-aft forces and inclination angles can be generated and supplied to drive the indoor wear tire loading fixture. Vehicle characterization involves mapping the basic dynamic load transfer behavior over a range of acceleration, deceleration and cornering maneuvers. A unique indoor vehicle test facility is described for efficiently capturing the tire forces and inclination angles during various maneuvers. All four tire positions can be characterized. Vehicle center of gravity (CG) accelerations and speeds are also recorded during indoor testing. An alternative to experimental measurements is the use of a vehicle computer model for mapping the basic dynamic load transfer behavior. Empirical equations relating vehicle kinematics to tire forces and inclination angles have been developed and are presented. A method of utilizing these equations together with outdoor wear course measurements for predicting transient tire force histories is presented. The method is demonstrated and validated with several vehicle case studies. The tire force component of a wear course can be characterized by measurement of a few parameters: the vehicle CG accelerations and the longitudinal velocity. Course characterization is illustrated using the Department of Transportation's Uniform Tire Quality Grading wear course in the San Angelo, TX area. The full 650 km course was characterized and combined with the laboratory characterization of a 1997 Pontiac Grand Am. Four 650 km drive files were created, one for each tire position, for an indoor wear machine. These consisted of five time-based parameters: radial load, lateral force, wheel torque (acceleration, deceleration forces), inclination angle, and velocity. By sequencing a tire through these four drive files, it was “rotated” as it would have been on the actual vehicle. Examples of tire wear rates and irregular wear are shown for a number of tire constructions, comparing the indoor to the outdoor results. Good correlation was achieved. This simulation technique permits the tire force spectrum of quite complex and lengthy routes to be accurately reproduced in the precisely controlled environment of the laboratory. Each cornering maneuver, each braking and acceleration event, every hill and town can be reproduced in real-time. Only by combining the specific vehicle dynamics of a given vehicle with that of a specific wear route can tire wear be accurately simulated. This tire-vehicle system simulation methodology is referred to as a TS-Sim model.

Tire Lateral Vibration Considerations in Vehicle-Based Tire Testing

2019 ◽  
Vol 47 (3) ◽  
pp. 211-231
Author(s):  
Anton Albinsson ◽  
Fredrik Bruzelius ◽  
P. Schalk Els ◽  
Bengt Jacobson ◽  
Egbert Bakker
Keyword(s):  
Lateral Force ◽  
Testing Procedure ◽  
Operating Conditions ◽  
Tire Model ◽  
Root Cause ◽  
Tire Force ◽  
Model Parameterization ◽  
Tire Testing ◽  
Suspension Model ◽  
Tire Models

ABSTRACT Vehicle-based tire testing can potentially make it easier to reparametrize tire models for different road surfaces. A passenger car equipped with external sensors was used to measure all input and output signals of the standard tire interface during a ramp steer maneuver at constant velocity. In these measurements, large lateral force vibrations are observed for slip angles above the lateral peak force with clear peaks in the frequency spectrum of the signal at 50 Hz and at multiples of this frequency. These vibrations can lower the average lateral force generated by the tires, and it is therefore important to understand which external factors influence these vibrations. Hence, when using tire models that do not capture these effects, the operating conditions during the testing are important for the accuracy of the tire model in a given maneuver. An Ftire model parameterization of tires used in vehicle-based tire testing is used to investigate these vibrations. A simple suspension model is used together with the tire model to conceptually model the effects of the suspension on the vibrations. The sensitivity of these vibrations to different operating conditions is also investigated together with the influence of the testing procedure and testing equipment (i.e., vehicle and sensors) on the lateral tire force vibrations. Note that the study does not attempt to explain the root cause of these vibrations. The simulation results show that these vibrations can lower the average lateral force generated by the tire for the same operating conditions. The results imply that it is important to consider the lateral tire force vibrations when parameterizing tire models, which does not model these vibrations. Furthermore, the vehicle suspension and operating conditions will change the amplitude of these vibrations and must therefore also be considered in maneuvers in which these vibrations occur.

Sign in / Sign up

Export Citation Format

Share Document