A Sliding Mode Observer for Vehicle Slip Angle and Tire Force Estimation

SUMMARYSliding mode observer is a variable structure system where the dynamics of a nonlinear system is altered via application of a high-frequency switching control. This paper presents a non-linear sliding mode observer for wheel linear slip and slip angle estimation of a single wheel based on its kinematic model and velocity measurements with added noise to simulate actual on-board sensor measurements. Lyapunov stability theory is used to establish the stability conditions for the observer. It is shown that the observer will converge in a finite time, provided the observer gains satisfy constraints based on a stability analysis. To validate the observer, linear and two-dimensional (2D) test rigs are specially designed. The sliding mode observer is tested under a variety of conditions and it is shown that the sliding mode observer can estimate wheel slip and slip angle to a high accuracy. It is also shown that the sliding mode observer can accurately predict wheel slip and slip angle in the presence of noise, by testing the performance of the sliding mode observer after adding white noise to the measurements. An extended Kalman filter is also developed for comparison purposes. The sliding mode observer is better in terms of prediction accuracy.

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Tire Characteristics Estimation Method Independent of Road Surface Conditions

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2018.p0138 ◽

2018 ◽

Vol 30 (1) ◽

pp. 138-144 ◽

Cited By ~ 1

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.

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Estimate Lateral Tire Force Based on Yaw Moment without Using Tire Model

ISRN Mechanical Engineering ◽

10.1155/2014/934181 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Jun Yang ◽

Wuwei Chen ◽

Yan Wang

Keyword(s):

Heuristic Method ◽

Least Square Method ◽

Least Square ◽

Force Estimation ◽

Tire Force ◽

Highly Nonlinear ◽

Road Friction ◽

Estimation Scheme ◽

Tire Force Estimation ◽

Yaw Moment

This paper demonstrates the implementation of a model-based vehicle estimator, which can be used for lateral tire force estimation without using any highly nonlinear tire-road friction models. The lateral tire force estimation scheme has been designed, and it consists of the following three steps: the yaw moment estimation based on a disturbance observer, the sum of the lateral tire force of two front tires and two rear tires estimation based on a least-square method, and individual lateral tire force estimation based on a heuristic method. The proposed estimator is evaluated under two typical driving conditions and the estimation values are compared with simulator data from CarSim and experimental data provided by GM. Results to date indicate that this is an effective approach, which is considered to be of potential benefit to the automotive industry.

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