Handling Stability Improvement Through Robust Active Front Steering and Active Differential Control (original) (raw)

NOTES on STEERING and STABILITY, Rev. D

Steering is required to control the direction of the vehicle, and for this to occur efficiently it is necessary that tire scrub, which produces disturbance forces, be minimized. Minimization of tire scrub from other causes other than steering, i.e. suspension scrub resulting from lateral linkage movement/toe in-out/camber changes/castor and-or kignpin angle, are also investigated. However, the handling, i.e. steering and stability, character of an automobile depends mainly upon its responses to steering and disturbance inputs. To investigate the nature of automotive steering and stability a simplified (linear relationships, no suspension, low speeds, steady-state) mathematical model is initially presented and then developed further. Therefore this paper begins with the steering geometry…

Modeling the steering wheel influence by the driver on the vehicle's motion stability

E3S Web of Conferences, 2021

In this article, a mathematical model was developed to influence the intensity of the steering wheel turn by the driver on the vehicle's stability. Comparison of the developed mathematical model with the experiment results made it possible to establish their adequacy. The effect of the three conditional drivers on the intensity of the steering wheel was examined. When performing the 'J-turn' maneuver, comparing the indices of the 1st, 2nd and 3rd conditional drivers, their proximity to the requirements of the standard was established. It was found that the indices of the second conditional driver are closest to the standard requirements. When performing the 'Single Lane Change' maneuver by the first conventional driver, the standard deviation value from the specified trajectory was 0.102, and the correlation index was 0.88.

Design and simulation of an integrated active yaw control system for road vehicles

International Journal of Vehicle Design, 2010

Active vehicle safety systems for road vehicles play an important role in accident prevention. In recent years, rapid developments have been observed in this area with advancing technology and electronic control systems. Active yaw control is one of I would like to state my appreciation to Murat Şahin for his patient support and pleasant friendship, Emir Kutluay for his useful advises and company at every part of the study, Görkem Oktay and Hakan Temizsoy for their abundantly helpful and enjoyable attitude throughout this thesis. After all these years, I have got quite a bunch of friends in the department, which I cannot stop without stating my appreciation to all of them. Also, financial support of TÜBĐTAK is also gratefully acknowledged. My endless thankfulness goes to my friend Zeynep Erdoğan, who has stimulated and supported me with patience and wisdom. Without her, this study would never finish. My last, but not the least, thanks go to my valuable family. They have endlessly supported, guided and protected me in all stages of my life. I can never imagine a life without their love and dedication. x

Vehicle Steering Dynamic Calculation and Simulation

International Journal of Innovative Technology and Interdisciplinary Sciences, 2018

This paper presents fundamental mathematical estimations of vehicle sideslip in stationary conditions regarding the influences of the vehicle parameters such as the tire stiffness, the position of gravity centre, the vehicle speed and the turning radius. The vehicle dynamics on steady state and transient responses are also investigated to see the effects of the yaw natural frequency and yaw damping rate on the steering system. Results from this study can be used in designing an automatic control of tracking vehicle in the future.

Vehicle Pure Yaw Moment control using differential tire slip

2009 American Control Conference, 2009

Direct yaw moment control generated by differential friction forces on an axle has been proved to be effective in improving vehicle lateral yaw stability and in enhancing handling performance. It consists of two levels of control tasks: calculating a yaw moment command at vehicle level and regulating the tire slip to deliver the moment at wheel level. Advanced powertrain with electrical in-wheel-motor makes fast wheel level control possible. This paper proposes an adaptive tire slip controller for Pure Yaw Moment Generation, which yields the maximal axle yaw moment by asymmetric axle friction force with no effect on vehicle longitudinal speed. Since the maximal friction is limited by the tire-road contact, control constraints at various vehicle speeds and on different surface conditions has to be taken into account. This algorithm can generate the optimal longitudinal slip ratio at the presence of lateraltireforcebasedona2DModified-LuGre tire model. One major difficulty of such type controllers is the unknown surface condition. A nonlinear adaptive braking/traction torque control is proposed to regulate the tire slip ratio with the estimation of surface condition. Simulation studies show that feeding back the estimate into the slip control makes the delivered friction force and yaw moment adaptive to surface conditions.

Analysis of the loss of vehicle motion stability in the conditions of steering control disturbance

MATEC Web of Conferences

Disturbances in the vehicle motion may be caused by different factors and in many cases are the reason for dangerous traffic incidents. Disturbances within the human-vehicle system are particularly hazardous. An innovative method was designed for analyzing and simulating the process of loss of vehicle motion stability after interference in the steering system, e.g. by acting on the steering wheel by the passenger. The subject of the study is the theoretical and experimental analysis of the vehicle motion path kinematics together with the duration of the disturbance, driver’s reaction time and steering wheel turning angles. PC-Crash simulation software was employed for the purpose of studying the disturbance characteristics and their influence on the loss of vehicle motion stability. It is recognized that the studied issues are as yet poorly understood, the presented results expand our knowledge base in this area and can be employed for the purpose of analysis of actual traffic accid...

An intelligent approach to the lateral forces usage in controlling the vehicle yaw rate

Asian Journal of Control, 2011

A direct yaw moment control system (DYC) is designed to improve the handling and stability of a four-wheel-drive electric vehicle. The main task of this paper is to use the lateral forces in the process of optimally controlling vehicle stability. This is performed by defining a variable optimum region for the slip ratio of each wheel. A hierarchical structure is selected to design the control system. The higher-level control system controls the yaw rate of the vehicle based on the fuzzy logic technique. The lower-level control system, installed in each wheel, maintains the slip ratio of the same wheel within an optimum region using the fuzzy logic technique. This optimum region for each wheel is continuously modified based on the impact of the lateral force on the generated control yaw moment and the friction coefficient of the road. Therefore, an algorithm for estimation of the friction coefficient is proposed. Computer simulations are carried out to investigate the effectiveness of the proposed method. This is accomplished by comparison of the results of control methods with a fixed slip ratio region and the results of the proposed method with a variable slip ratio region in some maneuvers. The robustness of the proposed controller against hard braking and noise contamination, as well as the effect of steering wheel angle amplitude, is verified. The simulation results show that the influence of the proposed method on enhancing vehicle performance is significant.

Influence of Road Excitation and Steering Wheel Input on Vehicle System Dynamic Responses

Applied Sciences, 2017

Considering the importance of increasing driving safety, the study of safety is a popular and critical topic of research in the vehicle industry. Vehicle roll behavior with sudden steering input is a main source of untripped rollover. However, previous research has seldom considered road excitation and its coupled effect on vehicle lateral response when focusing on lateral and vertical dynamics. To address this issue, a novel method was used to evaluate effects of varying road level and steering wheel input on vehicle roll behavior. Then, a 9 degree of freedom (9-DOF) full-car roll nonlinear model including vertical and lateral dynamics was developed to study vehicle roll dynamics with or without of road excitation. Based on a 6-DOF half-car roll model and 9-DOF full-car nonlinear model, relationship between three-dimensional (3-D) road excitation and various steering wheel inputs on vehicle roll performance was studied. Finally, an E-Class (SUV) level car model in CARSIM ® was used, as a benchmark, with and without road input conditions. Both half-car and full-car models were analyzed under steering wheel inputs of 5 • , 10 • and 15 •. Simulation results showed that the half-car model considering road input was found to have a maximum accuracy of 65%. Whereas, the full-car model had a minimum accuracy of 85%, which was significantly higher compared to the half-car model under the same scenario.

Composite Nonlinear Feedback for Vehicle Active Front Steering

In this paper, Composite Nonlinear Feedback (CNF) is applied on Active Front Steering (AFS) system for vehicle yaw stability control in order to have an excellent transient response performance. The control method, which has linear and nonlinear parts that work concurrently capable to track reference signal very fast with minimum overshoot, fast settling time, and without exceed nature of actuator saturation limit. Beside, modelling of 7 degree of freedom for typical passenger car with magic formula to represent tyre nonlinearity behaviour is also presented to simulate controlled vehicle as close as possible with a real situation. An extensive computer simulation is performed with considering a various profile of cornering manoeuvres with external disturbance to evaluate its performance in different scenarios. The performance of the proposed controller is compared to conventional Proportional Integration and Derivative (PID) for effectiveness analysis.

Fuzzy logic based yaw stability control for active front steering of a vehicle

Journal of Mechanical Science and Technology, 2014

Yaw stability control is an important consideration for improving the stability and handling behavior of a vehicle during extreme steering maneuvers. This paper proposes a fuzzy logic based yaw stability controller for an active front steering of a four-wheeled road vehicle by using steer-by-wire system. The proposed control system takes the yaw rate error, the steering angle given by the driver and the vehicle body side slip angle as inputs, for calculating the additional steering angle as output for stabilizing the yaw moment of the vehicle. A three degrees-of-freedom vehicle model is considered. Performance of the proposed system is simulated for sinusoidal, step maneuver using Matlab/Simulink tool, and the results are compared with the existing fuzzy control system which uses two inputs such steering angle and yaw rate. The simulation results show better performance of the proposed fuzzy based yaw controller as compared with the existing control system.