Abstract

The article considers the active safety system of road freight transport. The stereoscopic computer vision is the core of the system. The article also describes the major algorithms of active safety and the accuracy characteristics of algorithms’ application. Document type: Part of book or chapter of book

Abstract

The main objective of the present thesis focuses on the integration of the in-wheel electric motors into the conception and control of road vehicles. The present thesis is the subject of the grant 186-654 (2010-2013) between the Laboratory of Signals and Systems (L2S-CNRS) and the French Institute of Petrol and New Energies (IFPEN). The thesis work has originally started from a vehicular electrification project, equipped with in-wheel electric motors at the rear axle, to obtain a full electric urban use and a standard extra-urban use with energy recovery at the rear axle in braking phases. The standard internal combustion engines have the disadvantage that complex estimation techniques are necessary to compute the instantaneous engine torque. At the same time, the actuators that control the braking system have some delays due to the hydraulic and mechanical circuits. These aspects represent the primary motivation for the introduction and study of the integration of the electric motor as unique propelling source for the vehicle. The advantages brought by the use of the electric motor are revealed and new techniques of control are set up to maximize its novelty. Control laws are constructed starting from the key feature of the electric motor, which is the fact that the torque transmitted at the wheel can be measured, depending on the current that passes through the motor. Another important feature of the electric motor is its response time, the independent control, as well as the fact that it can produce negative torques, in generator mode, to help decelerate the vehicle and store energy at the same time. Therefore, the novelty of the present work is that the in-wheel electric motor is considered to be the only control actuator signal in acceleration and deceleration phases, simplifying the architecture of the design of the vehicle and of the control laws. The control laws are focused on simplicity and rapidity in order to generate the torques which are transmitted at the wheels. To compute the adequate torques, estimation strategies are set up to produce reliable maximum friction estimation. Function of this maximum adherence available at the contact between the road and the tires, an adequate torque will be computed in order to achieve a stable wheel behavior in acceleration as well as in deceleration phases. The critical issue that was studied in this work was the non-linearity of the tire-road interaction characteristics and its complexity to estimate when it varies. The estimation strategy will have to detect all changes in the road-surface adherence and the computed control law should maintain the stability of the wheel even when the maximum friction changes. Perturbations and noise are also treated in order to test the robustness of the proposed estimation and control approaches.; L'objectif principal de cette thèse est l'étude de l'exploitation de systèmes moteurs-roues (machines électriques intégrées à la roue) pour le contrôle de la dynamique véhicule. Cette thèse est issue d'un co-financement (numéro 186-654, 2010-2013) entre le Laboratoire des Signaux et Systèmes (CNRS) et l'Institut Français du Pétrole et Énergies Nouvelles (IFPEN). Les avantages apportés par l'utilisation du moteur électrique sont avérés et de nouvelles techniques de contrôle sont développées pour optimiser son utilisation. Les lois de contrôle basent généralement sur la grandeur principale du moteur électrique: le couple transmis, qui peut être mesuré via le courant consommé. Une autre caractéristique importante du moteur électrique est son temps de réponse, avec le fait qu'il peut produire des couples négatifs, pour ralentir le véhicule, tout en stockant l'énergie. La nouveauté du présent travail est de considérer le moteur-roue électrique comme seul signal de contrôle dans des phases d'accélération et des phases de ralentissement, simplifiant l'architecture de la conception du véhicule et des lois de contrôle. Pour répondre à la demande conducteur tout en préservant un comportement sain du véhicule, des stratégies d'estimation de la limite d'adhérence seront présentées. En fonction de cette adhérence maximale disponible entre la route et les pneus, un couple adéquat sera calculé pour assurer un comportement stable dans des phases d'accélération aussi bien que de freinage. L'aspect critique étudié dans ce travail est la non-linéarité des caractéristiques d'interaction entre la route et le pneu et la complexité de son estimation dans des conditions variables. La stratégie d'estimation devra détecter tous les changements d'adhérence de route et la loi de contrôle calculée devra maintenir la stabilité véhicule même lorsque la friction maximale change. Certaines formes de perturbation et de bruit seront également prises en compte afin de tester la robustesse des approches d'estimation et de contrôle proposés. Parmi les systèmes de sécurité active les plus importants en phase d'accélération, le système de contrôle de traction (TCS) rétablit la traction si les roues commencent à patiner et le programme de stabilité électronique (ESP) intervient pour prévenir une perte menaçante du contrôle latéral du véhicule. Dans le cas du freinage, le système décisif est le système d'antiblocage (ou ABS), qui empêche le blocage des roues. On peut trouver d'autres systèmes embarqués, comme le système de distribution de force de freinage électronique (EBD), qui assure une distribution optimale de la force de freinage transmise aux roues, pour éviter de déraper et assure un ralentissement stable du véhicule. Les systèmes embarqués qui fournissent les estimations doivent être robustes aux bruits de mesure et aux perturbations. A fortiori, ces calculs doivent être faits en temps réel, donc une complexité réduite et une réponse rapide de la loi de contrôle sont nécessaires. Enfin, l'environnement dans lequel le véhicule fonctionne est dynamique, les caractéristiques d'adhérence peuvent varier en fonction de l'état de la route et de la météo. Ainsi, on ne peut prévoir les réactions du conducteur pouvant influencer la réponse globale du véhicule dans des situations d'urgence. Le contrôleur devrait prendre en compte tous ces aspects pour préserver un comportement stable du véhicule. Bien que le contrôle latéral du véhicule présente une importance majeure dans la stabilité globale du véhicule, le présent travail est concentré sur le contrôle longitudinal du véhicule, puisqu'il représente le point de départ de la dynamique véhicule.

Abstract

dents involving Vulnerable Road Users (VRU) are still a very significant issue for road safety. ´PROactive Safety for PEdestrians and CyclisTs´ is a collaborative research project funded by the European Commission. The objective of PROSPECT is to significantly improve the effectiveness of active VRU safety systems compared to those currently on the market by: (i) expanding the scope of scenarios addressed (ii) improving the overall Autonomous Emergency Braking (AEB) system performance (iii) proposing extensive validation methodologies. Concepts for sensors and control systems will be shown in three vehicle demonstrators and a mobile driving simulator and tested with novel VRU dummy specimen. Those systems address the well-known barriers of current AEB systems such as limited sensors field-of-view, fuzzy path prediction, unreliable intent recognition and slow reaction times for the actuation. The findings contribute not only to the augmentation of state-of-the-art knowledge but as well to technical innovations like assessment methodologies and tools for testing.

Abstract

Objective: We studied which current fatal at-fault crashes would occur despite the most advanced current active safety devices (up to SAE level 2 of driving automation) and how frequent these crashes would be. Methods: We carried out a cross-sectional study of passenger cars that were first registered during the period 1st January 2010 to 31st December 2017 in Finland. To gain the true exposure for these cars, we accessed the national Vehicular and Driver Data Register to obtain the mileage information and the registration count for the study period of 2010-17. Similarly, we accessed the registry of Finnish road accident investigation teams and included all fatal at-fault crashes among the cars in our study for the same period. We used a real world reference technology for each active safety system in our analysis and chose one car brand as an example. This gave us exact system specifications and enabled testing the operation of the systems on the road. We performed field tests to gain further information on the precise operation of the safety systems in different operating conditions. Finally, we gathered all information on the studied active safety systems and analyzed the investigated at-fault fatal crashes case-by-case using our four level method. Results: Cars in our study were the primary party in 113 investigated fatal accidents during the years 2010-17. In 87 of the accidents, the leading cause of death was the injuries due to the crash, and these cases were classified as “unavoidable” (n = 58, 67 %), “avoidable” (n = 26, 30 %) or unsolved (n = 3, 3 %). Of the 58 “unavoidable” crashes 21 (36 %) were suicides, 21 (36%) involved active driver input which would have prevented the safety system operation, 15 (17 %) featured circumstances beyond the safety system performance and in one loss-of-control crash the driver had disabled the relevant safety system (electronic stability control). The registration years of the cars in our study (2010-17) totaled 3,772,864 and during this period, the cars travelled 75.9billion kilometers. The crash incidence of the “unavoidable” at-fault fatal crashes was 0.76-0.80 fatal crashes per billion kilometers and 15-16 fatal crashes per million registration years. Conclusions: We calculated a crash incidence for the “unavoidable” crashes which was 20–27% smaller than the observed crash rate of ESC-fitted passenger cars in our previous study. We concluded that suicides, active driver input until the crash, and challenging weather and road conditions are the most difficult factors for current active safety systems. Our analysis did not account for issues such as system usability or driver acceptance and therefore our results should be regarded as something that is currently theoretically achievable. However, the observed incidence is a good reference for automated driving development and the crash rate of automated cars. Peer reviewed

Abstract

The process of developing new automotive systems includes various testing cycles to assure a save operation in traffic. Physical system testing on test tracks is very important for this purpose, but rather expensive and might only become possible in later stages of the development process. Using a virtual simulation environment offers a safe possibility of testing new systems in early stages of development. Aditionally, driver-in-the-loop tests at test track and in a virtual simulator make it possible to evaluate driver reaction and potential acceptance by the future users of those systems. Within PROSPECT the new functions are investigated under various aspects in several simulator studies and test track studies. This deliverable D7.3 gives detailed information of conduction and results of the each study. Three studies focus exclusively on the for Vulnerable Road Users (VRUs) specifically dangerous urban intersection scenarios. The first of those studies examines the driver behaviour in a turning situation when a byciclist might be crossing. The described phenomena are looked-but-failed-to-see and failed-to-look. The second study, which provides an initial step in this line of research, analyzed the acceptance of issued forward collision warning times. The positioning of the potential accident opponent and the subjective feeling towards the criticality of the situation by the driver were key parameters taken into account. Last, but not least the acceptance of an intersection assist autonomous emergency braking systems was tested regarding the acceptance of potential buyers. The study was run for five days in a row for each participant to be able to judge the behaviour in a comuting situation. Two studies focused on longitudinal scenarios. Both studies followed the same design, but one was conducted on a test track and the other one in a simulator. The main objective was to investigate drivers reactions to FCW warnings and Active Steering interventions in critical VRU scenarios in case of a distraction of the driver. Additionally, the test track study was used to validate the results from the simulator study. The results of those studies are the basis for a wide acceptance evaluation of the systems. No system is an asset in increasing road safety if it is not accepted by the user and therefore turned off, if it is not required the system to be default on in consumer tests. Complemented by an additional acceptance study where the participants had to give their opinion of those systems after they watched videos of dangerous situations, the acceptance was analyzed based on questionnaires developed in PROSPECT and reported in Deliverable 7.2. This wholistic approach allows an expert discussion on the potentials of the PROSPECT functions in the future.