Identification of maximum road friction coefficient and optimal slip ratio based on road type recognition

2014 ◽  
Vol 27 (5) ◽  
pp. 1018-1026 ◽  
Author(s):  
Hsin Guan ◽  
Bo Wang ◽  
Pingping Lu ◽  
Liang Xu
Keyword(s):  
Friction Coefficient ◽  
Slip Ratio ◽  
Optimal Slip Ratio ◽  
Road Friction ◽  
Road Type ◽  
Road Friction Coefficient

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.

Wireless Piezoelectric Sensor for the Measurement of Tire Deformations and the Estimation of Slip Angle

2009 ◽  
Author(s):  
Gurkan Erdogan ◽  
Lee Alexander ◽  
Rajesh Rajamani
Keyword(s):  
Friction Coefficient ◽  
Piezoelectric Sensor ◽  
Slip Angle ◽  
Lateral Deformation ◽  
Test Rig ◽  
Slip Ratio ◽  
Lateral Deflection ◽  
Road Friction ◽  
Tire Forces ◽  
Road Friction Coefficient

This paper introduces a wireless piezoelectric tire sensor whose readings can be utilized for the estimation of various tire variables such as slip angle, slip ratio, tire forces and tire road friction coefficient. In this paper, the proposed sensor is demonstrated for the estimation of tire slip angle. Lateral deformation of the tire is decoupled from radial and longitudinal tire deformations using a special sensor design. The decoupled lateral deflection profile of the tire is employed to estimate the slip angle. A new tire test rig is constructed to experimentally evaluate the performance of the developed sensor. Results show that the tire sensor can accurately estimate slip angles up to values of 5.0 degrees.

scholarly journals Slip Control of Electric Vehicle Based on Tire-Road Friction Coefficient Estimation

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Gaojian Cui ◽  
Jinglei Dou ◽  
Shaosong Li ◽  
Xilu Zhao ◽  
Xiaohui Lu ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Electric Vehicle ◽  
Slip Ratio ◽  
Braking Performance ◽  
Slip Control ◽  
Coefficient Estimation ◽  
Road Friction ◽  
Braking Torque ◽  
Novel Method ◽  
Road Friction Coefficient

The real-time change of tire-road friction coefficient is one of the important factors that influence vehicle safety performance. Besides, the vehicle wheels’ locking up has become an important issue. In order to solve these problems, this paper comes up with a novel slip control of electric vehicle (EV) based on tire-road friction coefficient estimation. First and foremost, a novel method is proposed to estimate the tire-road friction coefficient, and then the reference slip ratio is determined based on the estimation results. Finally, with the reference slip ratio, a slip control based on model predictive control (MPC) is designed to prevent the vehicle wheels from locking up. In this regard, the proposed controller guarantees the optimal braking torque on each wheel by individually controlling the slip ratio of each tire within the stable zone. Theoretical analyses and simulation show that the proposed controller is effective for better braking performance.

Tire–road friction coefficient estimation based on designed braking pressure pulse

2021 ◽  
pp. 095440702098358
Author(s):  
Juqi Hu ◽  
Subhash Rakheja ◽  
Youmin Zhang
Keyword(s):  
Friction Coefficient ◽  
Unscented Kalman Filter ◽  
Estimation Accuracy ◽  
Accurate Estimation ◽  
Vehicle Speed ◽  
Two Stage ◽  
Slip Ratio ◽  
Road Friction ◽  
Vehicle Motion ◽  
Road Friction Coefficient

Knowledge of tire–road friction coefficient (TRFC) is valuable for autonomous vehicle control and design of active safety systems. This paper investigates TRFC estimation on the basis of longitudinal vehicle dynamics. A two-stage TRFC estimation scheme is proposed that limits the disturbances to the vehicle motion. A sequence of braking pressure pulses is designed in the first stage to identify desired minimal pulse pressure for reliable estimation of TRFC with minimal interference with the vehicle motion. This stage also provides a qualitative estimate of TRFC. In the second stage, tire normal force and slip ratio are directly calculated from the measured signals, a modified force observer based on the wheel rotational dynamics is developed for estimating the tire braking force. A constrained unscented Kalman filter (CUKF) algorithm is subsequently proposed to identify the TRFC for achieving rapid convergence and enhanced estimation accuracy. The effectiveness of the proposed methodology is evaluated through CarSim™-MATLAB/Simulink™ co-simulations considering vehicle motions on high-, medium-, and low-friction roads at different speeds. The results suggest that the proposed two-stage methodology can yield an accurate estimation of the road friction with a relatively lower effect on the vehicle speed.

scholarly journals Study on Pre-Warning Method of the Lateral Security of Heavy Vehicle in Deteriorative Weather

2014 ◽  
Vol 8 (1) ◽  
pp. 292-296
Author(s):  
Zhi-Guo Zhao ◽  
Min Chen ◽  
Nan Chen ◽  
Yong-Bing Zhao ◽  
Xin Chen
Keyword(s):  
Friction Coefficient ◽  
Critical Speed ◽  
Warning System ◽  
Heavy Vehicle ◽  
Heavy Vehicles ◽  
Core Technology ◽  
Road Friction ◽  
Turning Radius ◽  
Safety Features ◽  
Road Friction Coefficient

The lateral security of heavy vehicle in deteriorative weather is one of the main causes of accidents of vehicles on roads. Road safety has become a subject of great concern to institutions of higher education and scientific research institutions. There are important theoretical and practical significances to explore applicable and effective lateral safety warning methods of heavy vehicles. One of the purposes of this paper is to provide a good theoretical basis for the core technology of heavy vehicle safety features for our country's independent research and development. Aiming at the issue of lateral security of heavy vehicle for road conditions in deteriorative weather, this paper constructs the framework of the lateral security pre-warning system of heavy vehicles based on cooperative vehicle infrastructure. Moreover, it establishes vehicle lateral security statics model through analysis of the force of the car in the slope with section bending and states the parameters of vehicles for no rollover. The side slip is indexed to calculate critical speed of vehicles in a bend. This paper also analyzes the influence of road friction coefficient, the road gradient and the turning radius on the lateral security of the vehicle with critical speed on the asphalt pavement with surface conditions ranging from wet, dry, snowing or icy. The calculation results show that the bad weather road conditions, road friction coefficient and turning radius have obvious influence on the lateral security critical speed. Experimental results indicate that the critical speed error warning is within 4% and it meets the design requirements.

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