A New Method for Estimating Road Friction Coefficient

2010 ◽  
Vol 139-141 ◽  
pp. 2622-2625
Author(s):  
Fen Lin
Keyword(s):  
Friction Coefficient ◽  
Traffic Safety ◽  
Sliding Mode ◽  
Estimation Algorithm ◽  
Longitudinal Force ◽  
Recursive Least Squares ◽  
Force Estimation ◽  
Road Friction ◽  
Vehicle Activity ◽  
Road Friction Coefficient

Road friction coefficient is a critical component in traffic safety. The estimation of tire–road friction coefficient at tires allows the control algorithm in vehicle activity system to adapt to external driving conditions. This paper develops a new tire–road friction coefficient estimation algorithm based on tire longitudinal force estimation and tire slip estimation. Vehicle tire longitudinal forces are estimated by sliding mode observer combined with Kalman filter. Based on the tire forces estimation, road friction coefficient is estimated by recursive least squares algorithm (RLS). The test conditions which contain different friction level road are established in ADAMS/Car. The conclusions validate the reliability and efficiency of the proposed method for estimating the friction coefficient in different adhesion level roads. The research also indicates the theory of slip slope can also be reappeared in virtual experiment based on ADAMS.

scholarly journals Optimal Spacing Policy for Vehicle Platoon Control with Road-Friction Coefficient

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Lei Zuo ◽  
Duo Meng ◽  
Jinqi Zhang
Keyword(s):  
Friction Coefficient ◽  
Sliding Mode ◽  
The Road ◽  
Optimization Framework ◽  
Control Scheme ◽  
Road Friction ◽  
Vehicle Platoon ◽  
Optimal Spacing ◽  
The Stability ◽  
Road Friction Coefficient

This paper investigates the vehicle platoon control problems, in which the road-friction coefficient is taken into consideration. In order to improve the vehicle platoon safety in various road-friction conditions, an optimal spacing policy is proposed for the vehicle platoon. In detail, an intervehicle space optimization framework is developed by using a safety cost function and the gradient decent method. In this way, the optimal intervehicle spacing headway is presented such that the vehicle can be safely driven to the desired platoon under various road-friction conditions. Then, based on the proposed optimal spacing policy, we transform this optimal spacing vehicle platoon control problem into a moving target tracking problem. An adaptive distributed integrated sliding mode (DISM)-based vehicle platoon control scheme is proposed such that the vehicles can effectively follow the presented optimal spacing platoon. Moreover, the stability of the proposed vehicle platoon system is strictly analyzed and numerical simulations are provided to verify the proposed approaches.

scholarly journals Study on Road Friction Database for Automated Driving - Fundamental Consideration of Measuring Device for Road Friction Database -

2021 ◽  
Author(s):  
Tetsunori Haraguchi ◽  
Ichiro Kageyama ◽  
Yukiyo Kuriyagawa ◽  
Tetsuya Kaneko ◽  
Motohiro Asai ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Traffic Safety ◽  
Surface Condition ◽  
Automated Driving ◽  
Friction Coefficients ◽  
Measuring Device ◽  
The Road ◽  
Road Friction ◽  
Road Friction Coefficient ◽  
Fundamental Consideration

This research deals with the possibility for construction of the database on the braking friction coefficient for actual roads from the viewpoint of traffic safety especially for automated driving such as level 4 or higher. In an automated driving such levels, the controller needs to control the vehicle, but the road surface condition, especially the road friction coefficient on wet roads, snowy or icy roads, changes greatly, and in some cases, changes by almost one order. Therefore, it is necessary for the controller to constantly collect environment information such as the road friction coefficients and prepare for emergencies such as obstacle avoidance. However, at present, the measurement of the road friction coefficients is not systemically performed, and a method for accurately measuring has not been established. In order to improve this situation, this study examines a method for continuously measurement for the road friction characteristics such as μ-s characteristics.

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.

Estimation of the Maximum Tire-Road Friction Coefficient

2003 ◽  
Vol 125 (4) ◽  
pp. 607-617 ◽  
Author(s):  
Steffen Mu¨ller ◽  
Michael Uchanski ◽  
Karl Hedrick
Keyword(s):  
Friction Coefficient ◽  
Estimation Algorithm ◽  
Road Surface ◽  
Measurement Noise ◽  
Misclassification Rate ◽  
The Road ◽  
Subtle Effect ◽  
Road Friction ◽  
Friction Estimation ◽  
Road Friction Coefficient

We develop and test a “slip-based” method to estimate the maximum available tire-road friction during braking. The method is based on the hypothesis that the low-slip, low-μ parts of the slip curve used during normal driving can indicate the maximum tire-road friction coefficient, μmax. We find support for this hypothesis in the literature and through experiments. The friction estimation algorithm uses data from short braking maneuvers with peak accelerations of 3.9 m/s2 to classify the road surface as either dry μmax≈1 or lubricated μmax≈0.6. Significant measurement noise makes it difficult to detect the subtle effect being measured, leading to a misclassification rate of 20%.

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