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 Robust Vehicle Dynamics Control for a Sharp Curve With Uncertain Road Condition

2021 ◽  
Vol 9 ◽  
Author(s):  
Jing Miao ◽  
Yifan Dai ◽  
Ou Xie ◽  
Hao Chen ◽  
Fuzhou Niu ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Robust Optimization ◽  
Control Strategy ◽  
Autonomous Vehicles ◽  
Lateral Dynamics ◽  
The Road ◽  
Road Friction ◽  
The Stability ◽  
Vehicle Dynamics Control ◽  
Road Friction Coefficient

Recently, more and more research has been conducted to develop Connected Autonomous Vehicles (CAVs) applications that ensures the safety driving of CAVs under some extreme situations. This brief presents a robust control strategy for CAVs to preserve a precise tracking performance and maintain the stability of lateral dynamics when passing a sharp curve with uncertain road friction coefficient changes. In the proposed robust lateral dynamics control, robust optimization-based lateral dynamics controller is designed to achieve the stability of the lateral dynamics with the consideration of the road friction coefficient uncertainty. Simulation validations are carried out to evaluate the proposed control strategy. The results show that the robust optimization-based lateral dynamics can improve the robustness even with the uncertainty of the road friction coefficient.

A review on identification methods of road friction coefficient

2021 ◽  
Vol 15 ◽  
Author(s):  
Gengxin Qi ◽  
Xiaobin Fan ◽  
Hao Li
Keyword(s):  
Friction Coefficient ◽  
Autonomous Driving ◽  
Research Direction ◽  
Identification Methods ◽  
Research Status ◽  
The Road ◽  
Road Friction ◽  
Coefficient Measurement ◽  
Estimation System ◽  
Road Friction Coefficient

Background: The development of the tire/road friction coefficient measurement and estimation system has far-reaching significance for the active electronic control safety system of automobiles and is one of the core technologies for autonomous driving in the future. Objective: Estimating the road friction coefficient accurately and in real-time has become the leading research direction. Researchers have used different tools and proposed different algorithms and patents. These methods are widely used to estimate the road friction coefficient or other related parameters. This paper gives a comprehensive description of the research status in the field of road friction coefficient estimation. Method: According to the current research status of Chinese and foreign scholars in the field of road friction coefficient recognition, the recognition methods are mainly divided into two categories: Cause-based and Effect-based. Results: This literature review will discuss the existing two types of identification methods (Cause-based and Effect-based), and the applicable characteristics of each algorithm are analyzed. Conclusion: The two recognition methods are analyzed synthetically, and the development direction of road friction coefficient recognition technology is discussed.

Hierarchical Nonlinear Moving Horizon Estimation of Vehicle Lateral Speed and Road Friction Coefficient

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Chi Jin ◽  
Anson Maitland ◽  
John McPhee
Keyword(s):  
Friction Coefficient ◽  
Numerical Optimization ◽  
Optimization Problems ◽  
Global Optimum ◽  
Moving Horizon Estimation ◽  
The Road ◽  
Nominal Model ◽  
Road Friction ◽  
High Level ◽  
Road Friction Coefficient

Abstract In this paper, we address nonlinear moving horizon estimation (NMHE) of vehicle lateral speed, as well as the road friction coefficient, using measured signals from sensors common to modern series-production automobiles. Due to nonlinear vehicle dynamics, a standard nonlinear moving horizon formulation leads to non-convex optimization problems, and numerical optimization algorithms can be trapped in undesirable local minima, leading to incorrect solutions. To address the challenge of non-convex cost functions, we propose an estimator with a two-level hierarchy. At the high level, a grid search combined with numerical optimization aims to find reference estimates that are sufficiently close to the global optimum. The reference estimates are refined at the low level leading to high-precision solutions. Our algorithm ensures that the estimates converge to the true values for the nominal model without the need for accurate initialization. Our design is tested in simulation with both the nominal model as well as a high-fidelity model of Autonomoose, the self-driving car of the University of Waterloo.

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 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.

Robust adaptive anti-slip regulation controller for a distributed-drive electric vehicle considering the driver’s intended driving torque

2017 ◽  
Vol 232 (4) ◽  
pp. 562-576 ◽  
Author(s):  
Zhuoping Yu ◽  
Renxie Zhang ◽  
Xiong Lu ◽  
Chi Jin ◽  
Kai Sun
Keyword(s):  
Friction Coefficient ◽  
Electric Vehicle ◽  
State Feedback Control ◽  
Slip Ratio ◽  
The Road ◽  
Road Friction ◽  
Distributed Drive Electric Vehicle ◽  
Robust Adaptive ◽  
Driving Torque ◽  
Road Friction Coefficient

A robust adaptive anti-slip regulation controller which consists of two components, namely a road friction coefficient estimator and a wheel dynamics controller, is designed for distributed-drive electric vehicles. The road friction coefficient estimator is based on the latest non-affine parameter estimation theory to achieve the peak road friction coefficient. Also, working conditions for the road friction coefficient estimator are proposed to avoid the estimation error caused by a small slip ratio. According to the results of the road friction coefficient estimator, the desired reference slip ratio is obtained and the key parameters of the robust adaptive anti-slip regulation controller are modified to make sure that the road conditions can be made full use of. Then, according to the desired reference slip ratio, a state feedback control law with a conditional integrator is designed on the basis of the Lyapunov stability theory for a wheel dynamics controller by analysis of the non-linear characteristics of the tyres and the driver’s intended driving torque and constraints from the ground–tyre adhesion. In addition, it achieves smooth switching between optimal driving and the driver’s intended driving torque rather than normal switching logic. Multi-condition simulations and experiments show that the controller is adaptive to different road conditions, can improve the driving efficiency of the vehicle and can ensure stability of the vehicle. Finally, with comparative experiments, the distributed-drive electric vehicle with a robust adaptive anti-slip regulation controller proves to be more efficient than the traditional vehicle with a traditional anti-slip regulation controller.

Comprehensive prediction method of road friction for vehicle dynamics control

2009 ◽  
Vol 223 (8) ◽  
pp. 987-1002 ◽  
Author(s):  
L Li ◽  
J Song ◽  
H-Z Li ◽  
D-S Shan ◽  
L Kong ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Control Systems ◽  
Vehicle Dynamics ◽  
Control Mode ◽  
Fusion Method ◽  
The Road ◽  
Comprehensive Method ◽  
Road Friction ◽  
Vehicle Dynamics Control ◽  
Road Friction Coefficient

The contact friction characteristic between a tyre and the road is a key factor that dominates the dynamics performance of a vehicle under critical conditions. Vehicle dynamics control systems, such as anti-lock braking systems, traction control systems, and electronic stability control systems (e.g. Elektronisches Stabilitäts Programm (ESP)), need an accurate road friction coefficient to adjust the control mode. No time delay in the estimation of road friction should be allowed, thereby avoiding the disappearance of the optimal control point. A comprehensive method to predict the road friction is suggested on the basis of the sensor fusion method, which is suitable for variations in the vehicle dynamics characteristics and the control modes. The multi-sensor signal fusion method is used to predict the road friction coefficient for a steering manoeuvre without braking; if active braking is involved, simplified models of the braking pressure and tyre force are adopted to predict the road friction coefficient and, when high-intensity braking is being considered, the neural network based on the optimal distribution method of the decay power is applied to predict the road friction coefficient. The method is validated through a ground test under complicated manoeuvre conditions. It was verified that the comprehensive method predicts the road friction coefficient promptly and accurately.

scholarly journals Distributed Integrated Sliding Mode-Based Nonlinear Vehicle Platoon Control with Quadratic Spacing Policy

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Lei Zuo ◽  
Ye Zhang ◽  
Maode Yan ◽  
Wenrui Ma
Keyword(s):  
Sliding Mode ◽  
Quadratic Function ◽  
External Disturbances ◽  
Time Headway ◽  
Driving Behaviors ◽  
Traffic Capacity ◽  
Control Scheme ◽  
Mode Method ◽  
Vehicle Platoon ◽  
The Stability

This paper investigates the nonlinear vehicle platoon control problems with external disturbances. The quadratic spacing policy (QSP) is applied into the platoon control, in which the desired intervehicle distance is a quadratic function in terms of the vehicle’s velocities. Comparing with the general constant time headway policy (CTHP), the QSP is more suitable to the human driving behaviors (HDB) and can improve the traffic capacity. Then, a novel platoon control scheme is proposed based on the distributed integrated sliding mode (DISM). Since the external disturbances are taken into consideration, the sliding mode method is employed to handle the disturbances. Moreover, the stability and string stability of the proposed platoon control system are strictly analyzed. In final, numerical simulations are provided to verify the proposed approaches.

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