Simultaneous Estimation of Vehicle’s Center of Gravity and Inertial Parameters Based on Ackermann’s Steering Geometry

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Zitian Yu ◽  
Junmin Wang
Keyword(s):  
Estimation Method ◽  
Lateral Force ◽  
Front Wheel ◽  
Center Of Gravity ◽  
Simultaneous Estimation ◽  
Force Model ◽  
Force Term ◽  
Motion Equations ◽  
Tire Force ◽  
Inertial Parameters

Onboard vehicle parameter estimation is an important procedure for advanced vehicle control tasks, especially for vehicles whose payload configurations vary in day-to-day use. This study presents a newly proposed estimation method based on the Ackermann’s steering geometry (ASG) that aims to estimate multiple vehicle's center of gravity (CG) position and inertial parameters at the same time. In this method, the vehicle planar motion equations are first synthesized into a form where only the lateral force of one front wheel and longitudinal forces appear. This way, the influence of uncertainties in the tire lateral force models is greatly reduced. Then, the condition of eliminating the remaining front wheel lateral force term can be derived, which is exactly the Ackermann’s steering geometry. When the influence of lateral tire force terms are eliminated, regression technique is applied to estimate the needed vehicle parameters. Vehicle’s suspension kinematics is also considered in the processing of dynamic signals. Unlike conventional methods in estimating vehicle’s payload related parameters, the new method requires neither lateral tire force model nor accurate suspension property parameters. Simulations in CarSim®-Simulink environment verified that the proposed method is capable of estimating vehicle parameters such as CG position and inertial parameters at the same time.

A New Method in Estimating Vehicle Center of Gravity Position Parameters Based on Ackermann’s Steering

2016 ◽  
Author(s):  
Zitian Yu ◽  
Junmin Wang
Keyword(s):  
Front Wheel ◽  
Center Of Gravity ◽  
New Method ◽  
Recursive Least Squares ◽  
Vehicle Model ◽  
3 Dimensional ◽  
Tire Force ◽  
Tire Forces ◽  
System Configurations

The determination of vehicle’s center of gravity position is an important but challenging task for control of advanced vehicles such as automated vehicles, especially under daily usage condition where the system configurations and payload condition may change. To address this problem, a new method is proposed in this paper to estimate the vehicle’s 3-dimensional center of gravity position parameters without relying on detailed suspension configuration parameters or lateral tire force models. In the estimation problem, the vehicle’s planar dynamic equations are synthesized together to reduce the number of unknown lateral tire forces, then the condition of Ackermann’s Steering Geometry can be found to eliminate the influence of the remaining unknown front wheel lateral tire forces. When the unknown tire forces are cancelled, the recursive least squares (RLS) regression technique is used to identify the 3-dimensional center of gravity position parameters. The vehicle model with the sprung mass modeled as an inverted pendulum is developed to assist the analysis and conversion of sensor measured signals. Simulations conducted in a high-fidelity CarSim® vehicle model have demonstrated the capability of this proposed method in estimating the vehicle’s center of gravity position parameters.

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.

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.

Steering and Stability of Single-track Vehicles

1951 ◽  
Vol 5 (1) ◽  
pp. 191-213 ◽  
Author(s):  
R. A. Wilson-Jones
Keyword(s):  
Lateral Force ◽  
Front Wheel ◽  
Slip Angle ◽  
Single Track ◽  
Motor Cycle ◽  
Low Mass ◽  
Low Speeds ◽  
The Stability ◽  
Straight Ahead

The author briefly states the elementary principles of equilibrium and claims that the stability of the conventional bicycle or motor cycle is automatic except at very low speeds. This is because the steering automatically turns in the direction in which the machine is leaning and returns to the straight ahead position when the machine is restored to the vertical. The achievement of these effects is largely due to the “trail” of the front wheel. The causes of “steering roll” and “steering wobble” and the purpose of the inclination of the steering head, are examined, as are the effects of high and low mass centres and of the rider leaning with and against the machine. It is shown how the elementary principles of steering apply to various types of vehicle, including single-track vehicles in which the necessary lateral force comes mainly from camber thrust rather than slip angle. The results are given of experiments on varying amounts of “trail”, and a method of measuring slip angles is described which is applicable to motor cycles. Finally, a method of indicating the direction of the torque applied to the handlebars when entering, holding, and leaving a bend is described.

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.

Research on the Cornering Characteristics of Three-Axle Vehicle

2014 ◽  
Vol 945-949 ◽  
pp. 567-570
Author(s):  
Bo Xu ◽  
Sheng Min Cui ◽  
Xiang Yu Wu
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Front Wheel ◽  
Heavy Vehicle ◽  
Sideslip Angle ◽  
Motion Equations ◽  
Dynamic Steering ◽  
Angular Scale ◽  
Control Target ◽  
The Stability

A multi-axle dynamic steering technology was proposed to solve the steering stability and maneuverability problem of heavy vehicle. Two degrees of freedom linear steering-model and motion-equations of three-axle vehicle was established. Taking the zero sideslip angle as the control target and the proportional rear-front wheel angle as control method, we got the angular scale-factor equation and related matrix of the state space and transfer function. The MATLAB software was used to simulate the different steering modes stability steady-state and transient response. The results show that by using proportional control method the sideslip angle can be stabilized near zero and by using multi-axle dynamic steering technology the stability and maneuverability of the vehicle when steering can be improved effectively.

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.

Sign in / Sign up

Export Citation Format

Share Document