Analyse du risque et détection de situations limites : application au développement des systèmes d'alerte au conducteur.

The problematic of the thesis enter within the framework of the preventive driving assistance systems by the study of the vehicle dynamic behavior and the application of the observers for the detection upstream of driving critical situations. In this work, we proposed a warning unit to provide information or an alarm to the driver, sufficiently in advance, in order to avoid road departure accidents, which takes into account several constraints: Excessive longitudinal speed even on straight road section, excessive lateral dynamic (excessive lateral acceleration and yaw rate), vehicle lateral positioning (excessive lateral displacement and relative yaw angle) and small values of time to lane crossing. To give a solution to the problem of the road departure accidents related to a problem of vehicle dynamics, a new model of critical speed in curve was developed. This model takes into account the evolution of the vehicle dynamics as well as the mechanical parameters. The detection algorithms were tested on several scenarios and alarms obtained correspond well to felt drivers and in the exact places.La problématique de la thèse entre dans le cadre des systèmes préventifs d'aide à la conduite par l'étude du comportement dynamique d'un véhicule automobile et l'application des observateurs en vue de la détection en amont de situations critiques de la conduite. Dans ce travail de thèse, nous avons proposé une unité d'avertissement pour fournir une information ou une alarme au conducteur, suffisamment en avance, afin d'éviter des accidents de type sortie de voie, en tenant compte de plusieurs critères : Vitesse longitudinale excessive, dynamique latérale excessive, positionnement latéral du véhicule et le temps à sortie de voie. Pour donner une solution au problème des accidents par sortie de voie liés à un problème de dynamique du véhicule, un nouveau modèle de vitesse critique en courbe a été développé. Ce modèle prend en compte l'évolution de la dynamique du véhicule ainsi que les paramètres mécaniques. Les algorithmes de détection ont été testés sur plusieurs scénarios et les alertes obtenues correspondent bien aux ressentis des conducteurs et aux endroits exacts

Integrated Driver-Vehicle-Infrastructure Road Departure Warning Unit

International audienceIn this paper, a road-departure warning unit taking into account driver-vehicle-infrastructure (DVI) interactions is proposed. The longitudinal and lateral vehicle dynamics limits are analyzed to detect the road departure on loss of control. Vehicle positioning and time to lane crossing (TLC) are used to detect the road departure on a defect of guidance. Prevention of excessive longitudinal speed is handled through the computation of a critical longitudinal speed when approaching a curve and speed profile generation in the straight road section preceding the curve. For the lateral mode, the vehicle oversteering or understeering, the yaw motion, and the lateral acceleration are analyzed. The vehicle lateral displacement and the TLC values are also examined when the vehicle dynamics are not excessive. Necessary data for detection algorithms, which are not available from measurements, are estimated using an extended Kalman filter. The system consists of several subsystems, which work in parallel and provide warning through a dedicated human-machine interface (HMI). This road-departure warning system is experimentally tested on a test track using a prototype vehicle. It is found to be efficient and robust

Simultaneous vehicle state and road attributes estimation using unknown input Proportional-Integral observer

International audienceIn this paper, a global vehicle state and road attributes estimation method using the unknown input Proportional-Integral (PI) observer is proposed. The goal is to estimate simultaneously, the vehicle dynamics, the road bank angle and road friction coefficient in the presence of disturbance input. The observer gain is obtained as a solution of a Linear Matrix Inequalities (LMI) problem. Finally, an estimation procedure of the road slope angle in the presence of the pitching moment disturbance due to the load transfer during the acceleration or braking phase is proposed. Experimental results provided in the paper show the effectiveness of the approach

Advanced vehicle-infrastructure-driver speed profile for road departure accident prevention

International audienceIn this paper, we present a new method for the calculation of the maximal authorized speed in curves where the three elements of the situation, the vehicle, the driver, and the infrastructure are taken into account. The vehicle dynamics is represented by a four-wheel model that includes longitudinal slip and side-slip angle of the vehicle. Our analysis of the driver behaviour considers his ability during deceleration, taking into account the mobilized friction, while the infrastructure characteristics introduce a precise definition of the road geometry and the maximal available friction

Road departure detection using vehicle dynamics analysis

International audienc

Virtual Sensor: Simultaneous State and Input Estimation for Nonlinear Interconnected Ground Vehicle System Dynamics

This paper proposes a new observer approach used to simultaneously estimate both vehicle lateral and longitudinal nonlinear dynamics, as well as their unknown inputs. Based on cascade observers, this robust virtual sensor is able to more precisely estimate not only the vehicle state but also human driver external inputs and road attributes, including acceleration and brake pedal forces, steering torque, and road curvature. To overcome the observability and the interconnection issues related to the vehicle dynamics coupling characteristics, tire effort nonlinearities, and the tire–ground contact behavior during braking and acceleration, the linear-parameter-varying (LPV) interconnected unknown inputs observer (UIO) framework was used. This interconnection scheme of the proposed observer allows us to reduce the level of numerical complexity and conservatism. To deal with the nonlinearities related to the unmeasurable real-time variation in the vehicle longitudinal speed and tire slip velocities in front and rear wheels, the Takagi–Sugeno (T-S) fuzzy form was undertaken for the observer design. The input-to-state stability (ISS) of the estimation errors was exploited using Lyapunov stability arguments to allow for more relaxation and an additional robustness guarantee with respect to the disturbance term of unmeasurable nonlinearities. For the design of the LPV interconnected UIO, sufficient conditions of the ISS property were formulated as an optimization problem in terms of linear matrix inequalities (LMIs), which can be effectively solved with numerical solvers. Extensive experiments were carried out under various driving test scenarios, both in interactive simulations performed with the well-known Sherpa dynamic driving simulator, and then using the LAMIH Twingo vehicle prototype, in order to highlight the effectiveness and the validity of the proposed observer design

Integrated driver-vehicle-infrastructure road departure warning unit

A road-departure warning unit taking into account driver-vehicle-infrastructure (DVI) interactions is proposed. The longitudinal and lateral vehicle dynamics limits are analyzed to detect the road departure on loss of control. Vehicle positioning and time to lane crossing (TLC) are used to detect the road departure on a defect of guidance. Prevention of excessive longitudinal speed is handled through the computation of a critical longitudinal speed when approaching a curve and speed profile generation in the straight road section preceding the curve. For the lateral mode, the vehicle oversteering or understeering, the yaw motion, and the lateral acceleration are analyzed. The vehicle lateral displacement and the TLC values are also examined when the vehicle dynamics are not excessive. Necessary data for detection algorithms, which are not available from measurements, are estimated using an extended Kalman filter. The systemconsists of several subsystems, which work in parallel and provide warning through a dedicated human-machine interface (HMI). This road departure warning system is experimentally tested on a test track using a prototype vehicle. It is found to be efficient and robust

A human-centred Approach of Steering Control Modelling

International audienceFuture driving assistances will be designed in such a way that their action blends into the perceptual and motor control loops of the driver without yielding negative interference. This objective cannot be reached without integrating into the design process a model that allows making valid predictions on the behaviour of the driver. In that context, this paper will deal with the understanding and modelling of the driver's steering behaviour, with an emphasis on the role of visual information and kinaesthetic feedback. This paper describes strategies of steering and speed control used by the driver and the combined cornering and braking condition is analyzed. For the driver speed control, the information of driver visual direction is used to determinate anticipatory speed control during curve negotiation

Modélisation du conducteur pour le contrôle de la trajectoire d'un véhicule automobile

National audienceLe travail decrit dans ce papier propose un modele cybernetique du conducteur pour le controle de la trajectoire d'un vehicule automobile, qui integre explicitement la dynamique neuromotrice. Le modele conducteur propose prend en compte l'aspect visuel et retour d'effort en considerant le comportement anticipatoire et compensatoire du conducteur. Les parametres inconnus du modelesont identifies en utilisant un concept d'identification "boite grise", ainsi a partir des trajectoires de vehicule simulees, le systeme conducteur-vehicule est analyse par rapport aux variations parametriques. Les resultats de simulation presentes a la fin de l'article montrent bien que le modele developpe peut etre parametre pour representer differents styles de conduite