Articles de revues sur le sujet « Braking Maneuvers »
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F. Corzo, Santiago, D. E. Ramajo et N. M. Nigro. « Transient Numerical Assessment of Race Car Dry-Sump Oil Under Extreme Maneuvers ». International Journal of Automotive and Mechanical Engineering 15, no 3 (5 octobre 2018) : 5636–51. http://dx.doi.org/10.15282/ijame.15.3.2018.18.0433.
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A numerical assessment of a dry-sump oil system was performed by Computational Fluid Dynamics (CFD). Unlike conventional cars, race cars are subjected to high accelerations that induce oil sloshing. Hence, dry-sump oil systems are required to collect the oil outside of the engine prior to be pumped inside of it again. To avoid engine malfunctions, the dry-sump must guarantee continuously oil suction in every maneuver. To perform such simulations, the model was subjected to different car maneuvers extracted from data acquisition available from real race car. It has showed that single and combined maneuvers, such as acceleration, braking and turnings can induce downward, upward and lateral accelerations higher than 2 g during several seconds. Therefore, four different single maneuvers (acceleration, deceleration, turn right and turn left) as well as a set of contaminated maneuvers (braking and turning) were studied. Simulations were achieved by mean of the Volume of Fluid Method (VOF) for an air-oil system. The influence of the turbulence modeling was also investigated. First a forerunner design was analyzed and both the race car tests and CFD simulations showed that for the most extreme maneuvers (pure braking and combined with braking and turning right) the original design failed before the end of the maneuvers by air suction in the pump inlet. In consequence, the dry-sump was redesigned and assessed under these extreme conditions until to ensure stable oil aspiration.
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Kremer, Christina, Markus Tomzig, Nora Merkel et Alexandra Neukum. « Using Active Seat Belt Retractions to Mitigate Motion Sickness in Automated Driving ». Vehicles 4, no 3 (11 août 2022) : 825–42. http://dx.doi.org/10.3390/vehicles4030046.
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The introduction of automated-driving functions provides passengers with the opportunity to engage in non-driving related tasks during the ride. However, this benefit might be compromised by an increased incidence of motion sickness. Therefore, we investigated the effectiveness of active seat belt retractions as a countermeasure against motion sickness during inattentive automated driving. We hypothesized that seat belt retractions would mitigate motion sickness by supporting passengers to anticipate upcoming braking maneuvers, by actively tensioning their neck muscles and, thereby, reducing the extent of forward head movement while braking. In a motion base driving simulator, 26 participants encountered two 30 min automated drives in slow-moving traffic: one drive with active seat belt retractions before each braking maneuver and a baseline drive without. The results revealed that there was no difference in perceived motion sickness between both experimental conditions. Seat belt retractions resulted in an increased activity of the lateral neck muscles and supported drivers to anticipate braking maneuvers. However, at the same time, the retractions led to an increased magnitude of head movement in response to braking. This research lays the groundwork for future research on active seat belt retractions as a countermeasure against motion sickness and provides directions for future work.
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Koppa, Rodger J., Daniel B. Fambro et Richard A. Zimmer. « Measuring Driver Performance in Braking Maneuvers ». Transportation Research Record : Journal of the Transportation Research Board 1550, no 1 (janvier 1996) : 8–15. http://dx.doi.org/10.1177/0361198196155000102.
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A simple, reliable instrumentation package with an on-board computer for installation in a test vehicle or the test driver's own vehicle is described. This package was used in a research project recently completed, an empirical investigation of stopping sight distance. Selected data on perception-response time (PRT) and braking performance under artificial and simulated on-the-road emergency conditions are presented. PRTs were less than the AASHTO assumed constant of 2.5 sec even at the 95th percentile. Braking performance in terms of steady deceleration was greater than −0.32 g at the 95th percentile.
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Ming, Zhang, Nie Hong, Wei Xiao‐hui, Qian Xiaomei et Zhou Enzhi. « Modeling and simulation of aircraft anti‐skid braking and steering using co‐simulation method ». COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 28, no 6 (13 novembre 2009) : 1471–88. http://dx.doi.org/10.1108/03321640910992029.
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PurposeThe purpose of this paper is to introduce a co‐simulation method to study the ground maneuvers of aircraft anti‐skid braking and steering.Design/methodology/approachA virtual prototype of aircraft is established in the multibody system dynamics software MSC.ADAMS/Aircraft. The anti‐skid braking control model, which adopts the multi‐threshold PID control method with a slip‐velocity‐controlled, pressure‐bias‐modulated (PBM) system, is established in MATLAB/Simulink. EASY5 is used to establish the hydraulic system of nose wheel steering. The ADAMS model is connected to block diagrams of the anti‐skid braking control model in MATLAB/Simulink, and is also connected to the block diagrams of nose wheel steering system model in EASY5, so that the ground maneuvers of aircraft anti‐skid braking and steering are simulated separately.FindingsResults are presented to investigate the performance of anti‐skid braking system in aircraft anti‐skid simulation. In aircraft steering simulation, the influence of two important parameters on the forces acting on the tires is discussed in detail, and the safe area to prevent aircraft sideslip is obtained.Originality/valueThis paper presents an advanced method to study the ground maneuvers of aircraft anti‐skid braking and steering, and establishes an integrated aircraft model of airframe, landing gear, steering system, and anti‐skid braking system to investigate the interaction of each subsystem via simulation.
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Wu, Xingwei, Linda Ng Boyle et Dawn Marshall. « Drivers’ Avoidance Strategies When Using a Forward Collision Warning (FCW) System ». Proceedings of the Human Factors and Ergonomics Society Annual Meeting 61, no 1 (septembre 2017) : 1939–43. http://dx.doi.org/10.1177/1541931213601964.
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Forward collision warning (FCW) systems help prevent rear-end collisions by identifying and alerting drivers of threats ahead. Understanding drivers’ avoidance strategies i.e. the tendency to brake or steer is important for the design and effectiveness of these systems. A driving simulator study was performed across five US locations to examine three driver avoidance maneuvers: braking only, steering only and combined braking and steering. A log-linear analysis was used to investigate the likelihood of an avoidance maneuver given the driver characteristics (age, gender) and study location. Findings showed that drivers aged 40 years and older were more likely to use a combined braking and steering maneuver to avoid a rearend collision. Drivers from two coastal urban areas (Washington, D.C. and Seattle, WA) were less likely to choose braking only in response to FCW alerts. Younger drivers and drivers that live in more rural areas (Clemson, SC and Iowa City, IA) were more likely to select braking only to avoid a crash, which could be due to their experience in less congested traffic environment. The findings of this study provide some insights on the factors associated with various avoidance strategies among drivers. This understanding can help guide the design of future in-vehicle collision warning systems.
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Jurecki, Rafał S., Tomasz L. Stańczyk et Mateusz Ziubiński. « Analysis of the Structure of Driver Maneuvers in Different Road Conditions ». Energies 15, no 19 (26 septembre 2022) : 7073. http://dx.doi.org/10.3390/en15197073.
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The safety of road users is one of the priority issues taken into account in both the operation and design of vehicles. The presented work is part of a study that aims to develop a method for parametric assessment of driver behavior. The driving style of a driver depends on their skills and psychophysical characteristics, the type and performance of the vehicle used by the driver, and the type of road. This method involves the continuous measurement of the longitudinal and lateral acceleration values of a vehicle body. The paper analyzes how the type of road influences the structure of the maneuvers undertaken by the driver. The paper formulates criteria for distinguishing basic maneuvers (acceleration, braking, and turning). The structure of maneuvers was analyzed for two parameters: the extreme value of acceleration occurring during the execution of a given maneuver and the frequency of maneuvers during the passage of a given route. The analysis presented in this paper confirms that the type of road has a significant influence on the structure of the maneuvers undertaken by the driver.
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Huertas-Leyva, Pedro, Giovanni Savino, Niccolò Baldanzini et Marco Pierini. « Loss of Control Prediction for Motorcycles during Emergency Braking Maneuvers Using a Supervised Learning Algorithm ». Applied Sciences 10, no 5 (4 mars 2020) : 1754. http://dx.doi.org/10.3390/app10051754.
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The most common evasive maneuver among motorcycle riders and one of the most complicated to perform in emergency situations is braking. Because of the inherent instability of motorcycles, motorcycle crashes are frequently caused by loss of control performing braking as an evasive maneuver. Understanding the motion conditions that lead riders to start losing control is essential for defining countermeasures capable of minimizing the risk of this type of crashes. This paper provides predictive models to classify unsafe loss of control braking maneuvers on a straight line before becoming irreversibly unstable. We performed braking maneuver experiments in the field with motorcycle riders facing a simulated emergency scenario. The latter involved a mock-up intersection in which we generated conflict events between the motorcycle ridden by the participants and an oncoming car driven by trained research staff. The data collected comprises 165 braking trials (including 11 trials identified as loss of control) with 13 riders representing four categories of braking skill, ranging from beginner to expert. Three predictive models of loss of control events during braking trials, going from a basic model to a more advanced one, were defined using logistic regressions as supervised learning methods and using the area under the receiver operating characteristic (ROC) curve as a performance indicator. The predictor variables of the models were identified among the parameters of the vehicle kinematics. The best model predicted 100% of the loss of control and 100% of the full control cases. The basic and the more advanced supervised models were adapted for loss of control identification with time series data, and the results detecting in real-time the loss of control events showed excellent performance as well as with the supervised models. The study showed that expert riders may maintain stability under dynamic conditions that normally lead less skilled riders to a loss of control or falling events. The best decision thresholds of the most relevant kinematic parameters to predict loss of control have been defined. The thresholds of parameters that typically characterize the loss of control such as the yaw rate and front-wheel lock duration were dependent on the rider skill levels. The peak-to-root-mean-square ratio of roll acceleration was the most robust parameter for identifying loss of control among all skill levels.
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Koch, Andreas, Jonas Brauer et Jens Falkenstein. « Drivability Optimization of Electric Vehicle Drivetrains for Brake Blending Maneuvers ». World Electric Vehicle Journal 13, no 11 (4 novembre 2022) : 209. http://dx.doi.org/10.3390/wevj13110209.
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Electric vehicle drivetrains are considered a way to reduce greenhouse gas emissions from road traffic. The use of electric drives in automotive vehicles offers advantages, such as the potential to recover energy during braking (regenerative braking). The limitation of the maximum air gap torque of the vehicle drive machine by several factors requires a temporary standalone or simultaneous use of the conventional vehicle wheel brake. In several studies, it is shown that during braking operations, the drive machine and the vehicle wheel brake can induce torsional oscillations in the drivetrain, which have a negative influence on the driving comfort and lead to a high mechanical load. To reduce these oscillations, the simultaneous use of an active anti-jerk control is necessary. Due to the problem of oscillation excitations caused by a brake intervention, the used drivability function (integrated prefilter, anti-jerk control) is investigated and optimized with regard to brake blending maneuvers and the effectiveness for damping torsional oscillations. Therefore, the dynamics of the drivetrain are adapted to the dynamics of the braking system using the prefilter, which leads to precise fulfilment of the driver’s braking desire, even during dynamic brake blending maneuvers. All investigations are carried out with a hardware-in-the-loop test bench to create reproducible results.
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Cai, Haohao, et Xiaomei Xu. « Lateral Stability Control of a Tractor-Semitrailer at High Speed ». Machines 10, no 8 (20 août 2022) : 716. http://dx.doi.org/10.3390/machines10080716.
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To improve the high-speed lateral stability of the tractor-semitrailer, a lateral stability control strategy based on the additional yaw moment caused by differential braking is proposed and investigated based on the co-simulation environment. First of all, a five-degree-of-freedom (5-DOF) yaw-roll dynamic model of the tractor-semitrailer is established, and the model accuracy is verified. Secondly, the lateral stability control strategy of the tractor-semitrailer is proposed, two yaw moment controllers and the braking torque distributor are designed. Then, the effectiveness of the proposed control strategy and the influence of the yaw moment controller on the lateral stability of the tractor-semitrailer are investigated under the high-speed lane-change maneuvers. Finally, the controller robustness is discussed. Research results show that the proposed high-speed lateral stability control strategy can ensure the tractor-semitrailer to perform safely the single lane-change (SLC) maneuver at 110 km/h and the double lane-change (DLC) maneuver at 88 km/h; the yaw moment controller has significant influence on the lateral dynamic performance of the tractor-semitrailer; compared with the proportional-derivative (PD) control, the model predictive control (MPC) can make the tractor-semitrailer obtain better lateral stability under high-speed lane-change maneuvers; MPC and PD controllers exhibit good robustness to the considered vehicle parameter uncertainties.
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Chinnaraj, K., M. Sathya Prasad et C. Lakshmana Rao. « Experimental Analysis and Quasi-Static Numerical Idealization of Dynamic Stresses on a Heavy Truck Chassis Frame Assembly ». Applied Mechanics and Materials 13-14 (juillet 2008) : 271–80. http://dx.doi.org/10.4028/www.scientific.net/amm.13-14.271.
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The current trend in automotive design is to optimize components for weight. To achieve this, automotive designers need to have complete understanding of various stresses prevalent in different areas of the component. The chassis frame assembly of a heavy truck used for long distance goods hauling application is chosen for this investigation and dynamic stress-strain response of the component due to braking and cornering maneuvers are experimentally measured and reported. A quasi-static approach that approximates the dynamic maneuvers into number of small processes having static equilibriums is followed to carry out the numerical simulation, approximating the dynamic behavior of frame rail assembly during cornering and braking. With the help of commercial finite element package ANSYS, the quasi-static numerical simulations are carried out and compared with experimental results. This study helps in understanding prevailing stresses in truck frame rails especially during cornering and braking maneuvers and brings out all geometric locations that may be potential failure initiation locations. This study makes a case for further investigation on the effects of residual and assembly stresses on frame rails.
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Bosso, Nicola, Antonio Gugliotta, Matteo Magelli, Italo Francesco Oresta et Nicolò Zampieri. « Study of wheel-rail adhesion during braking maneuvers ». Procedia Structural Integrity 24 (2019) : 680–91. http://dx.doi.org/10.1016/j.prostr.2020.02.060.
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FANCHER, P., J. BERNARD, C. CLOVER et C. WINKLER. « REPRESENTING TRUCK TIRE CHARACTERISTICS IN SIMULATIONS OF BRAKING AND BRAKING-IN-A-TURN MANEUVERS ». Vehicle System Dynamics 27, sup001 (janvier 1997) : 207–20. http://dx.doi.org/10.1080/00423119708969655.
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Jeusette, J. P., et M. Theves. « Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads ». Tire Science and Technology 20, no 2 (1 avril 1992) : 83–105. http://dx.doi.org/10.2346/1.2139512.
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Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.
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YU, Feng, et Jun XIE. « Simulation analysis of efficiency and stability for vehicle’s ABS control on combined steering and braking maneuvers ». MATEC Web of Conferences 272 (2019) : 01024. http://dx.doi.org/10.1051/matecconf/201927201024.
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Eight degrees of freedom vehicle model was established. Using the method of fuzzy control, the ABS control algorithm was designed based on slip ratio. Simulation analysis was done at speed of 15m/s, 20m/s, 25m/s under turning braking. The results show that the vehicle braking performance and vehicle stability at middle or low speed was improved by using the ABS controller, but qualitative analysis shows that phenomenon of vehicle instability was appeared at high-speed conditions. The turning braking stability under ABS controller was judged quantificationally by the stability judging formula. The results show that the requirements of stability control could not meet with only Anti-lock Braking System.
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Xu, Jinliang, Wenzhen Lv, Chao Gao, Yufeng Bi, Minghao Mu et Guangxun E. « Why Do Drivers’ Collision Avoidance Maneuvers Tend to Cause SUVs to Sideslip or Rollover on Horizontal Curve and Grade Combinations?—An Analysis of the Causes Based on a Modified Multibody Dynamics Model ». International Journal of Environmental Research and Public Health 19, no 23 (29 novembre 2022) : 15877. http://dx.doi.org/10.3390/ijerph192315877.
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The extent to which drivers’ collision avoidance maneuvers affect the safety margins of sideslip and rollover is not captured by road geometric design theory. To quantify the effects of drivers’ collision avoidance maneuvers on the safety margins of sport utility vehicles (SUVs) on horizontal curve and grade combinations, a modified 8-degree-of-freedom multibody model based on SUVs was developed. The model was then used to calculate the design safety margins of sideslip and rollover for steady states and the actual safety margins for collision avoidance maneuvers. Subsequently, the design safety margin reduction rate (the difference between the design and actual safety margins divided by the design safety margin) was calculated and used to assess the safety margins. The results showed that the safety margins of SUVs were significantly reduced by braking, lane changing, and lane changing with braking. The marginal effects indicated that the greater the deceleration and the shorter the lane change duration, the greater the effect on the safety margins, particularly the sideslip safety margin. Furthermore, when the SUV was driven at 80 km·h−1 on grades with a horizontal curve radius of 270 m and 400 m, the sideslip safety margin with emergency braking (deceleration over −4.5 m·s−2) was reduced by 71% and 21%, and the rollover safety margin was reduced by 11% and 5%, respectively. Under these conditions, an emergency lane change (lane change duration less than 2 s) caused the SUV to sideslip and reduced the rollover safety margin by 47% (curve radius 270 m) and 45% (curve radius 400 m). Therefore, drivers’ collision avoidance maneuvers are a factor that cannot be neglected in alignment design.
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Siramdasu, Yaswanth, et Saied Taheri. « A Tool for Tire Handling Performance Evaluation ». Tire Science and Technology 44, no 2 (1 avril 2016) : 74–102. http://dx.doi.org/10.2346/tire.16.440201.
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ABSTRACT In the past, handling performance of the tire–vehicle combination has been evaluated using tire models such as the Pacejka Magic Formula. These models usually lack realistic representation of tire–road interaction and are not suitable for combined steering and braking maneuvers that may activate the antilock braking system. The objective of this study is to develop a computationally simple and accurate tire model, which can be used in the development and evaluation of handling performance of the tire on uneven road surfaces. For an emergency obstacle avoidance maneuver at high speeds, transient tire behavior plays a crucial role in the generation of forces between tire and road. Road undulations and steering inputs both induce high-frequency tire belt vibrations, which have detrimental effects on the handling and tractive behavior of the tire. To meet these requirements, a dynamic six degrees of freedom tire model–based rigid ring approach is developed and integrated with a multiple tandem elliptical cam to include enveloping behavior of the tire. The tire model that is developed in this research is partially based on the work of Schmeitz found in the literature. The tire model was parameterized using experimental parameters found in the literature. The tire model is validated using fixed axle high-speed oblique cleat experimental data. The developed tire model is integrated with the vehicle model in CarSim®. From the simulation of successive step steering input, the increasing influence of tire belt vibrations at higher slip angles was observed due to sudden steering wheel inputs. From the simulation of the step steering input on the bad asphalt road surface with an added cleat and on the flat smooth road surface, it was observed that the lateral performance of the tire at higher slip angles is strongly influenced by the vertical load variations. A single lane change maneuver was simulated on the smooth and bad asphalt road surfaces, demonstrating the strong influence of tire lateral and vertical belt vibrations on the lateral performance of the vehicle. Simulation of high-speed emergency obstacle avoidance braking maneuvers on measured rough and smooth roads showed that the influence of high-frequency vibrations due to road undulations and step steering inputs causes large variations of longitudinal and lateral forces at the axle, thus creating large variations in slip and slip angle of the tire with a degraded braking distance on rough roads.
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Allen, R. Wade, Henry T. Szostak et Theodore J. Rosenthal. « Modeling Driver/Vehicle Performance in Emergency Maneuvers ». Proceedings of the Human Factors Society Annual Meeting 32, no 10 (octobre 1988) : 573–77. http://dx.doi.org/10.1518/107118188786762711.
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The combined performance of the driver and vehicle determine whether accidents result from traffic conflicts, road hazards, etc. This paper describes the driver behavior and hazard scenario aspects of a computer simulation which models both vehicle dynamics and driver steering and braking behavior. The technical aspects of the simulation have previously been published. The issue of how much the driver and vehicle contribute to accident involvement is addressed, and antilock brake evaluation is used as an example.
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Kalinichenko, Yevgeniy, Mykhaylo Kourov et Kateryna Volovyk. « MANEUVER FOR STOPPING THE SHIP IN A SET POINT BY ACTIVE OR PASSIVE BRAKING AND CONCIDERING THE CURRENT ». Technology transfer : fundamental principles and innovative technical solutions 4 (30 novembre 2020) : 25–28. http://dx.doi.org/10.21303/2585-6847.2020.001473.
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The article deals with the use of active or passive braking of a ship to stop it at a given point. To substantiate the relevance of the study, an analysis of the literature on the problem of ensuring the safe maneuvering of ships was carried out, in which the issues of theoretical and experimental studies of the turnability of ships, the adequacy of the existing models of turnability to the real process of turning the ship, as well as the development of a system of autopilot control of the ship's heading using the principles of fuzzy logic were considered. Considerable attention is paid to the development of an information system for simulating the movement of ships with complex dynamic models. The necessary analytical expressions are given that characterize the dependences of the time and the distance traveled to the stop of the ship on the mode of active and passive braking, which are required to solve the problem posed in the work. A formal description of the maneuver for stopping the ship at a given point by active and passive braking is obtained. This description makes it possible to determine the moment of engine stop in case of passive braking or the moment of its reverse – in case of active braking, provided that the ship is following a heading equal to the bearing to a given point. Cases of presence and absence of current in the area of ship maneuver are considered. In the case of the presence of a current, two stages of the ship's movement are considered: from the zero moment of time until the moment of the start of braking, when the speed of the ship is unchanged, and the second stage, from the moment of the start of braking until the stop of the ship, when the speed of the ship decreases. To take into account the flow during braking with an exit to a given point, two methods are proposed. The first one is at a constant flow angle with a lateral displacement relative to the programmed trajectory of motion. And the second – with a variable flow angle at zero displacement relative to it. A successful check of the correctness of the results obtained by simulation computer modeling of maneuvers for stopping the ship at a given point of braking, taking into account the current, has been carried out
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Ali, Mohammad, Esteban R. Gelso et Jonas Sjoberg. « Automotive Threat Assessment Design for Combined Braking and Steering Maneuvers ». IEEE Transactions on Vehicular Technology 62, no 4 (mai 2013) : 1519–26. http://dx.doi.org/10.1109/tvt.2012.2231444.
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Itani, Khaled, et Alexandre De Bernardinis. « Electrothermal Multicriteria Comparative Analysis of Two Competitive Powertrains Applied to a Two Front Wheel Driven Electric Vehicle during Extreme Regenerative Braking Operations ». Energies 15, no 22 (14 novembre 2022) : 8506. http://dx.doi.org/10.3390/en15228506.
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The powertrain performance in an electric vehicle is fully dependent on the electrical and thermal constraints of the static converters ensuring the power transfer taking place between the energy storage systems and the electromechanical machines. These constraints depend on the architectures of the power converters, and their control strategies. Particularly, the maximal limits are reached in maneuvers such as hard regenerative braking circumstances. Indeed, braking recovery is a critical phase in the vehicle’s operation, and its duration and intensity may strongly impact the vehicle’s battery behavior or integrated hybrid storage system. The innovative objective of the paper is to propose an electrothermal multicriteria comparative study based on electrical and thermal criteria for two competitive powertrains. These semi-active power configurations (a 3-level DC/DC converter-based, and a Z-source converter-based) are implemented in a two-front wheel driven electric vehicle during extreme regenerative braking conditions. Open-loop and closed-loop controls were implemented in the Z-source using the maximal constant boost control with 3rd harmonic injection modulation technique. We considered two paralleled IGBT modules instead of the single shoot-through structure. Our approach is based on simulation during an extreme braking maneuver leading to heavy repercussions on the overall powertrain system. The aim is to investigate the challenging structure of the Z-source. Results showed that the proposed 3-level DC/DC-based topology has better performances in terms of power losses, efficiency, thermal behavior, and electromagnetic interference.
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Yarlagadda, Jahnavi, et Digvijay S. Pawar. « Heterogeneity in the Driver Behavior : An Exploratory Study Using Real-Time Driving Data ». Journal of Advanced Transportation 2022 (18 juin 2022) : 1–17. http://dx.doi.org/10.1155/2022/4509071.
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Driver behavior heterogeneity is a significant aspect to understand the individual behavioral variations and develop driver assistance systems. This study characterizes the heterogeneity in driving behavior using real-time driving performance features. In this context, the study investigates the extent of variations in the individual’s driving styles during routine driving. The driving styles are conceptualized using the vehicle kinematic data, that is, speed and accelerations performed during longitudinal control. The data is collected for 42 professional drivers using instrumented vehicle over a defined study stretch. An algorithm is developed for data extraction and total 7548 acceleration and 6156 braking maneuvers and corresponding driving performance features are extracted. The driving maneuver data are analyzed using the unsupervised techniques (PCA and K-means clustering) and three patterns of acceleration and braking are identified, which are further associated with two patterns of speed behavior. The results showed that each driver is found to exhibit different driving patterns in different driving regimes and no driver shows constantly safe or aggressive behavior. The aggression scores are found to be different among drivers, indicating the behavioral heterogeneity. This study results demonstrate that, driver’s level of aggression in different driving regimes is not constant and characterizing the driver by means of abstract driving features is not indicative of the diversified driving behavior. The proposed method identifies the individualized driving behaviors, reflecting the driver’s choice of driving maneuvers. Thus, the insights from the study are highly useful to design driver-specific safety models for driver assistance and driver identification.
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Yan, Menghua, Jinliang Xu, Shuo Han, Tian Xin, Ouyu Wang, Zemin Yi et Zhaoxin Liu. « Permitted speed decision of single-unit trucks with emergency braking maneuver on horizontal curves under rainy weather ». PLOS ONE 16, no 12 (30 décembre 2021) : e0261975. http://dx.doi.org/10.1371/journal.pone.0261975.
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Under adverse weather conditions, visibility and the available pavement friction are reduced. The improper selection of speed on curved road sections leads to an unreasonable distribution of longitudinal and lateral friction, which is likely to cause rear-end collisions and lateral instability accidents. This study considers the combined braking and turning maneuvers to obtain the permitted vehicle speed under rainy conditions. First, a braking distance computation model was established by simplifying the relationship curve between brake pedal force, vehicle braking deceleration, and braking time. Different from the visibility commonly used in the meteorological field, this paper defines "driver’s sight distance based on real road scenarios" as a threshold to measure the longitudinal safety of the vehicle. Furthermore, the lateral friction and rollover margin is defined to characterize the vehicle’s lateral stability. The corresponding relationship between rainfall intensity-water film thickness-road friction is established to better predict the safe speed based on the information issued by the weather station. It should be noted that since the road friction factor of the wet pavement not only determined the safe vehicle speed but also be determined by the vehicle speed, so we adopt Ferrari’s method to solve the quartic equation about permitted vehicle speed. Finally, the braking and turning maneuvers are considered comprehensively based on the principle of friction ellipse. The results of the TruckSim simulation show that for a single-unit truck, running at the computed permitted speed, both lateral and longitudinal stability meet the requirements. The proposed permitted vehicle speed model on horizontal curves can provide driving guidance for drivers on curves under rainy weather or as a decision-making basis for road managers.
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Esmaeili, Naser, Reza Kazemi et S. Hamed Tabatabaei Oreh. « Design of a new integrated controller (braking and steering) to maintain the stability of a long articulated vehicle ». Proceedings of the Institution of Mechanical Engineers, Part C : Journal of Mechanical Engineering Science 234, no 5 (20 novembre 2019) : 981–1013. http://dx.doi.org/10.1177/0954406219888235.
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As demands increase for goods transportation services, long articulated vehicles are introduced as a viable alternative to conventional heavy-duty vehicles. Nowadays, steering control systems are commonly used for enhancing the stability and handling of articulated vehicles. As situations become more difficult for the movement of a vehicle, the ability of the steering actuators decreases and it will not be possible to use this controller alone in critical maneuvers. Another effective way to adjust the directional dynamics of a long articulated vehicle is the simultaneous application of the braking and steering systems. In a situation where the vehicle is close to the ultimate steering limit, it is desirable to reduce the speed, and the steering system can be strengthened through the intervention of the braking system. In this article, a 23 degree of freedom dynamic model of the long articulated vehicle has been developed in MATLAB software. After determining the reference control variables, we will design a sliding mode controller to steer the tractor’s front axle and the semi-trailer’s rear axles. After defining and setting the weight coefficients using a performance indicator, we will design an integrated controller in a way that if maneuvers become more difficult to perform and the efficiency of the steering actuators decreases, the braking forces exerted on the tractor’s rear axle and the semi-trailer’s rear axles will take a share in regulating the vehicle’s movement. The main achievement of this article is the introduction of a new method to integrate braking and steering control systems in long articulated vehicles. The paper aims to prove that only if manoeuvres become more difficult to perform and the performance of steering actuators decreases, then braking forces can take part in regulating the vehicle’s movement.
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Selig, Michael, Boris Lorenz, Dirk Henrichmöller, Karsten Schmidt, Andrew Ball et Bo Persson. « Rubber Friction and Tire Dynamics : A Comparison of Theory with Experimental Data ». Tire Science and Technology 42, no 4 (1 octobre 2014) : 216–62. http://dx.doi.org/10.2346/tire.14.420403.
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ABSTRACT In this contribution, a simple rubber friction law is presented. The model can be used for tire and vehicle dynamics calculations [19]. The friction law is tested by comparing numerical results to the full rubber friction theory [6] and to experimental data. A two-dimensional tire model is introduced. The model combines the rubber friction law with a simple mass-spring description of the tire body. The tire model is very flexible and can be applied to different maneuvers. It can be used for calculating μ-slip curves, the self-aligning torque, braking and cornering, or combined motion (e.g., braking during cornering). The theory predictions are compared to measured data from indoor tire testing on sandpaper substrate. Simulations of antilock braking systems (ABS) using two different control algorithms are also presented.
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Klingbeil, W. W., et H. W. H. Witt. « Some Consequences of Coulomb Friction in Modeling Longitudinal Traction ». Tire Science and Technology 18, no 1 (1 janvier 1990) : 13–65. http://dx.doi.org/10.2346/1.2141691.
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Abstract A three-component model for a belted radial tire, previously developed by the authors for free rolling without slip, is generalized to include longitudinal forces and deformations associated with driving and braking. Surface tractions at the tire-road interface are governed by a Coulomb friction law in which the coefficient of friction is assumed to be constant. After a brief review of the model, the mechanism of interfacial shear force generation is delineated and explored under traction with perfect adhesion. Addition of the friction law then leads to the inception of slide zones, which propagate through the footprint with increasing severity of maneuvers. Different behavior patterns under driving and braking are emphasized, with comparisons being given of sliding displacements, sliding velocities, and frictional work at the tire-road interface. As a further application of the model, the effect of friction coefficient and of test variables such as load, deflection, and inflation pressure on braking stiffness are computed and compared to analogous predictions on the braking spring rate.
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Fauzi, Ahmad, Saiful Amri Mazlan et Hairi Zamzuri. « Modeling and Validation of Quarter Vehicle Traction Model ». Applied Mechanics and Materials 554 (juin 2014) : 489–93. http://dx.doi.org/10.4028/www.scientific.net/amm.554.489.
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This manuscript provides modeling and validation of a quarter car vehicle model to study the wheel dynamics behavior in longitudinal direction. The model is consists of a longitudinal slip model subsystem, a quarter body dynamic and tire subsystems. The quarter vehicle model was then validated using an instrumented experimental vehicle based on the driver input from brake and throttle pedals. Vehicle transient handling dynamic tests known as sudden braking test was performed for the purpose of validation. Several behaviors of the vehicle dynamics were observed during braking maneuvers such as body longitudinal velocity, wheel linear velocity and tire longitudinal slip at a quarter of the vehicle. Comparisons of the experimental results and model responses with sudden braking imposed motions were made. Consequently, the trends between simulation results and experimental data were found almost similar with an acceptable level of error for the application at hand.
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Rawat, Kamini, Vinod Kumar Katiyar et Pratibha Gupta. « Two-Lane Traffic Flow Simulation Model via Cellular Automaton ». International Journal of Vehicular Technology 2012 (22 août 2012) : 1–6. http://dx.doi.org/10.1155/2012/130398.
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Road traffic microsimulations based on the individual motion of all the involved vehicles are now recognized as an important tool to describe, understand, and manage road traffic. Cellular automata (CA) are very efficient way to implement vehicle motion. CA is a methodology that uses a discrete space to represent the state of each element of a domain, and this state can be changed according to a transition rule. The well-known cellular automaton Nasch model with modified cell size and variable acceleration rate is extended to two-lane cellular automaton model for traffic flow. A set of state rules is applied to provide lane-changing maneuvers. S-t-s rule given in the BJH model which describes the behavior of jammed vehicle is implemented in the present model and effect of variability in traffic flow on lane-changing behavior is studied. Flow rate between the single-lane road and two-lane road where vehicles change the lane in order to avoid the collision is also compared under the influence of s-t-s rule and braking rule. Using results of numerical simulations, we analyzed the fundamental diagram of traffic flow and show that s-t-s probability has more effect than braking probability on lane-changing maneuver.
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Mu¨ller, Steffen, Michael Uchanski et Karl Hedrick. « Estimation of the Maximum Tire-Road Friction Coefficient ». Journal of Dynamic Systems, Measurement, and Control 125, no 4 (1 décembre 2003) : 607–17. http://dx.doi.org/10.1115/1.1636773.
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We develop and test a “slip-based” method to estimate the maximum available tire-road friction during braking. The method is based on the hypothesis that the low-slip, low-μ parts of the slip curve used during normal driving can indicate the maximum tire-road friction coefficient, μmax. We find support for this hypothesis in the literature and through experiments. The friction estimation algorithm uses data from short braking maneuvers with peak accelerations of 3.9 m/s2 to classify the road surface as either dry μmax≈1 or lubricated μmax≈0.6. Significant measurement noise makes it difficult to detect the subtle effect being measured, leading to a misclassification rate of 20%.
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Higham, T. E. « Feeding, fins and braking maneuvers : locomotion during prey capture in centrarchid fishes ». Journal of Experimental Biology 210, no 1 (1 janvier 2007) : 107–17. http://dx.doi.org/10.1242/jeb.02634.
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Anistratov, Pavel, Björn Olofsson et Lars Nielsen. « Lane-deviation penalty formulation and analysis for autonomous vehicle avoidance maneuvers ». Proceedings of the Institution of Mechanical Engineers, Part D : Journal of Automobile Engineering 235, no 12 (9 avril 2021) : 3036–50. http://dx.doi.org/10.1177/09544070211007979.
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Autonomous vehicles hold promise for increased vehicle and traffic safety, and there are several developments in the field where one example is an avoidance maneuver. There it is dangerous for the vehicle to be in the opposing lane, but it is safe to drive in the original lane again after the obstacle. To capture this basic observation, a lane-deviation penalty (LDP) objective function is devised. Based on this objective function, a formulation is developed utilizing optimal all-wheel braking and steering at the limit of road–tire friction. This method is evaluated for a double lane-change scenario by computing the resulting behavior for several interesting cases, where parameters of the emergency situation such as the initial speed of the vehicle and the size and placement of the obstacle are varied, and it performs well. A comparison with maneuvers obtained by minimum-time and other lateral-penalty objective functions shows that the use of the considered penalty function decreases the time that the vehicle spends in the opposing lane.
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Yang, Fan, G. Yan et S. Rakheja. « Anti-Slosh Effectiveness of Baffles and Braking Performance of a Partly-Filled Tank Truck ». Applied Mechanics and Materials 541-542 (mars 2014) : 674–83. http://dx.doi.org/10.4028/www.scientific.net/amm.541-542.674.
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The liquid cargo movement within a partly-filled tank truck affects its braking, roll dynamics and directional performance in an adverse manner. In this study, the braking performance of a partly-filled tank truck equipped with different baffles designs is investigated considering dynamic fluid-structure interactions. The validity of the computational fluid dynamic model is examined through laboratory tests conducted on a scale model tank with and without baffles. The measured responses to harmonic excitations revealed three-dimensional nature of the fluid motion and couplings between the lateral and longitudinal fluid slosh. Several spectral components were observed for the transient slosh forces, which could be associated with the excitation, resonance, and beat frequencies. A dynamic pitch plane model of a Tridem truck incorporating three-dimensional fluid slosh dynamics is subsequently developed to analyze the fluid-vehicle interactions under straight-line braking maneuvers. The results show that the vehicle responses are highly influenced by the slosh-induced force and moment.
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Szydłowski, Tomasz, Krzysztof Surmiński et Damian Batory. « Drivers’ Psychomotor Reaction Times Tested with a Test Station Method ». Applied Sciences 11, no 5 (9 mars 2021) : 2431. http://dx.doi.org/10.3390/app11052431.
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The article presents the standard method of the evaluation of car drivers’ psychomotor reaction times. A characteristic feature of this method is the ability to conduct tests using real vehicles equipped with mobile measuring apparatus. Measurements are carried out on people whose task is to initiate specific maneuvers (such as: a braking or turning maneuver, a combined braking and turning maneuver, as well as e.g., the use of an audio signal) in response to external stimuli coming from different directions. The sources of the stimuli are light signals emitted by variable message signs placed around the vehicle. The developed control and measurement equipment allows us to realize various and complex test scenarios. It generates stimulus sequences, assesses the correctness of the driver’s response and measures its time. This method allows us to obtain sets of results from tests carried out under different conditions and variable test durations. The possibility of testing a large number of participants in a relatively short time and in repetitive conditions allows for reliable statistical inference. The paper presents examples of research results obtained on the basis of few thousand tests carried out on a large group of respondents. The registered data was statistically processed and referred to the literature. A high degree of correlation between the analyzed results and the literature reports proves that the presented method may be a source of data for the analysis of phenomena related to the time of the driver’s response, especially the influence of various factors affecting its values.
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Wang, Ziran, Guoyuan Wu et Matthew J. Barth. « Developing a Distributed Consensus-Based Cooperative Adaptive Cruise Control System for Heterogeneous Vehicles with Predecessor Following Topology ». Journal of Advanced Transportation 2017 (2017) : 1–16. http://dx.doi.org/10.1155/2017/1023654.
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Connected and automated vehicle (CAV) has become an increasingly popular topic recently. As an application, Cooperative Adaptive Cruise Control (CACC) systems are of high interest, allowing CAVs to communicate with each other and coordinating their maneuvers to form platoons, where one vehicle follows another with a constant velocity and/or time headway. In this study, we propose a novel CACC system, where distributed consensus algorithm and protocol are designed for platoon formation, merging maneuvers, and splitting maneuvers. Predecessor following information flow topology is adopted for the system, where each vehicle only communicates with its following vehicle to reach consensus of the whole platoon, making the vehicle-to-vehicle (V2V) communication fast and accurate. Moreover, different from most studies assuming the type and dynamics of all the vehicles in a platoon to be homogenous, we take into account the length, location of GPS antenna on vehicle, and braking performance of different vehicles. A simulation study has been conducted under scenarios including normal platoon formation, platoon restoration from disturbances, and merging and splitting maneuvers. We have also carried out a sensitivity analysis on the distributed consensus algorithm, investigating the effect of the damping gain on convergence rate, driving comfort, and driving safety of the system.
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Somà, Aurelio, Marco Aimar et Nicolò Zampieri. « Simulation of the Thermal Behavior of Cast Iron Brake Block during Braking Maneuvers ». Applied Sciences 11, no 11 (28 mai 2021) : 5010. http://dx.doi.org/10.3390/app11115010.
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In recent years, the interest in monitoring the operating conditions of freight wagons has grown significantly to improve the safety of railway vehicles. The railway research group of the Politecnico di Torino has been working for years on the development of solutions to effectively monitor the operating conditions of passenger and freight rail vehicles. As part of the national Cluster ITS Italy 2020 project funded by Italian ministry of education, university and research (MIUR), the Politecnico di Torino has collected a considerable amount of data thanks to the wired and wireless prototypes developed. The data obtained are used in this paper for the validation and calibration of a finite element (FE) model that simulates the temperature variation of a cast iron brake block due to braking operations of an intermodal freight wagon. The developed model can be a useful tool to predict the temperature at the wheel–shoe interface as a function of the current operating conditions since a direct measurement is not easy to perform.
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Yakub, Fitri, et Yasuchika Mori. « Enhancing Rollover Prevention and Vehicle Stability of Heavy Vehicle under Disturbance Effect ». Applied Mechanics and Materials 695 (novembre 2014) : 596–600. http://dx.doi.org/10.4028/www.scientific.net/amm.695.596.
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This study enhances the model predictive control for coordination of active rear steering and direct yaw moment control maneuvers for rollover prevention, lane change maneuver, and vehicle stability in heavy vehicle system under the influence of front steering angle as a disturbance to the system. A single-track mode of lateral-yaw motions based on a linearized vehicle model with linear tire characteristics is used for controller design, while the vehicle model used includes roll dynamic motion for the double-track model with a nonlinear tire model. We tested the vehicle at middle forward speed and we propose braking control algorithm based on left and right of rear wheels instead of front and rear wheels. The simulation results show the proposed coordinated control yielded better performance for rollover prevention, and also useful to maintain and enhance vehicle stability along the desired path, and has the ability to eliminate the effect of disturbance.
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Nazarov, Alexander, Vitalii Kashkanov, Roman Gumenyuk et Evgenui Kotik. « Substantiation of the influence of changes in the coefficient of axle distribution of braking force on the handling of a passenger car ». Journal of Mechanical Engineering and Transport 14, no 2 (janvier 2022) : 72–79. http://dx.doi.org/10.31649/2413-4503-2021-14-2-72-79.
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The article considers the change of the radius of the instantaneous center of rotation of a car moving along a curved trajectory during braking, taking into account the lateral input of the wheels of both axles of cars, both equipped with electronic tracking systems and not equipped with such. A criterion for assessing the controllability of cars moving on a curved trajectory in a braked state, by comparing the ratio of the current speed of the car to the longitudinal base with the ratio of the coefficients of lateral tire input to the product of the longitudinal base of the car, mass and cosines. It is established that the radius of instantaneous rotation of the longitudinal axis of the car moving along a curved trajectory during braking depends on the speed of the center of mass of the car, the coefficient of axle distribution of braking force, physical characteristics of applied tires, steering wheel angle and design and weight parameters. As a result, it allows you to set controllability. The authors obtained dependences that will create new algorithms for the operation of modern electronic control systems for stabilizing the longitudinal axis of a braked car, taking into account the speed of the car, its design and weight characteristics, the main characteristics of its braking system (coefficient of axle braking force distribution), physical characteristics used tires on wheels and connect them to the angles of the steered wheels, controlling the deviation of the longitudinal axis, which allows the driver to maintain the possibility of quite sharp maneuvers directly in the braking process, moving along a curved trajectory.
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Horri, Nadjim, Olivier Haas, Sheng Wang, Mathias Foo et Manuel Silverio Fernandez. « Mode Switching Control Using Lane Keeping Assist and Waypoints Tracking for Autonomous Driving in a City Environment ». Transportation Research Record : Journal of the Transportation Research Board 2676, no 3 (13 novembre 2021) : 712–27. http://dx.doi.org/10.1177/03611981211056636.
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This paper proposes a mode switching supervisory controller for autonomous vehicles. The supervisory controller selects the most appropriate controller based on safety constraints and on the vehicle location with respect to junctions. Autonomous steering, throttle and deceleration control inputs are used to perform variable speed lane keeping assist, standard or emergency braking and to manage junctions, including roundabouts. Adaptive model predictive control with lane keeping assist is performed on the main roads and a linear pure pursuit inspired controller is applied using waypoints at road junctions where lane keeping assist sensors present a safety risk. A multi-stage rule based autonomous braking algorithm performs stop, restart and emergency braking maneuvers. The controllers are implemented in MATLAB® and Simulink™ and are demonstrated using the Automatic Driving Toolbox™ environment. Numerical simulations of autonomous driving scenarios demonstrate the efficiency of the lane keeping assist mode on roads with curvature and the ability to accurately track waypoints at cross intersections and roundabouts using a simpler pure pursuit inspired mode. The ego vehicle also autonomously stops in time at signaled intersections or to avoid collision with other road users.
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Ghaffari, Ghazaleh, et Johan Davidsson. « Female kinematics and muscle responses in lane change and lane change with braking maneuvers ». Traffic Injury Prevention 22, no 3 (10 mars 2021) : 236–41. http://dx.doi.org/10.1080/15389588.2021.1881068.
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Chin, Yao-Wei, Jia Ming Kok, Yong-Qiang Zhu, Woei-Leong Chan, Javaan S. Chahl, Boo Cheong Khoo et Gih-Keong Lau. « Efficient flapping wing drone arrests high-speed flight using post-stall soaring ». Science Robotics 5, no 44 (22 juillet 2020) : eaba2386. http://dx.doi.org/10.1126/scirobotics.aba2386.
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The aerobatic maneuvers of swifts could be very useful for micro aerial vehicle missions. Rapid arrests and turns would allow flight in cluttered and unstructured spaces. However, these decelerating aerobatic maneuvers have been difficult to demonstrate in flapping wing craft to date because of limited thrust and control authority. Here, we report a 26-gram X-wing ornithopter of 200-millimeter fuselage length capable of multimodal flight. Using tail elevation and high thrust, the ornithopter was piloted to hover, fly fast forward (dart), turn aerobatically, and dive with smooth transitions. The aerobatic turn was achieved within a 32-millimeter radius by stopping a dart with a maximum deceleration of 31.4 meters per second squared. In this soaring maneuver, braking was possible by rapid body pitch and dynamic stall of wings at relatively high air speed. This ornithopter can recover to glide stability without tumbling after a 90-degree body flip. We showed that the tail presented a strong stabilizing moment under high thrust, whereas the wing membrane flexibility alleviated the destabilizing effect of the forewings. To achieve these demands for high thrust, we developed a low-loss anti-whirl transmission that maximized thrust output by the flapping wings to 40 grams in excess of body weight. By reducing the reactive load and whirl, this indirect drive consumed 40% less maximum electrical power for the same thrust generation than direct drive of a propeller. The triple roles of flapping wings for propulsion, lift, and drag enable the performance of aggressive flight by simple tail control.
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Khanse, Karan R., Yaswanth Siramdasu et Saied Taheri. « Development of a Simulink-CarSim Interaction Package for ABS Simulation of Discrete Tire Models ». Tire Science and Technology 44, no 1 (1 janvier 2016) : 2–21. http://dx.doi.org/10.2346/tire.16.440101.
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ABSTRACT Automotive and tire companies have to spend extensive amounts of time and money to tune their products through prototype testing at dedicated test facilities. This is mainly because of the limitations in the simulation capabilities that exist today. With greater competence in simulation comes more control over designs in the initial stages, which in turn lowers the demand for the expensive stage of tuning. This article aims at taking today's simulation capabilities a step forward by integrating models that are best developed in different software interfaces. An in-plane rigid ring tire model has been developed to understand the transient response of tires to various high-frequency events such as antilock braking and short-wavelength road disturbances. A rule-based antilock braking systems (ABS) model performed the high-frequency braking operation. The tire and ABS models were created in the Matlab-Simulink environment. A vehicle model was developed in CarSim. The models developed in Simulink were integrated with the vehicle model in CarSim, in the form of a design tool that can be used by tire as well as car designers for further tuning of the vehicle functional performances, as they relate to handling and braking maneuvers. The straight-line ABS performance was predicted using these models for a sample vehicle, and the results were substantiated through physical outdoor tests on the same vehicle to validate the developed integration package. The tool development, simulation results, and the objective test will be discussed.
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Liu, Difei, Stanford Chihuri, Thelma Mielenz, Linda Hill, Carolyn DiGuiseppi, David Strogatz et Guohua Li. « DIABETES MELLITUS AND HARD BRAKING EVENTS IN OLDER DRIVERS ». Innovation in Aging 6, Supplement_1 (1 novembre 2022) : 754. http://dx.doi.org/10.1093/geroni/igac059.2738.
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Abstract There are an estimated 37 million people with diabetes mellitus (DM) in the United States, including 16 million older adults. DM can impair patients’ driving safety due to diabetic peripheral neuropathy, hypoglycemia, or hyperglycemia, and eye diseases. However, few studies have examined the association between DM and driving safety based on naturalistic driving data. Data for this study came from the Longitudinal Research on Aging Drivers (LongROAD) project, a multisite naturalistic driving study of 2990 drivers aged 65–79 years at baseline. Driving data for the study participants were recorded by in-vehicle recording devices for up to 44 months. We used multivariable negative binomial modeling to estimate the incidence rate ratios (IRRs) and 95% confidence intervals (CIs) of hard braking events (i.e., proxies for unsafe driving behavior defined as maneuvers with deceleration rates ≥ 0.4 g) associated with DM. Of the 2856 study participants eligible for this study, 482 (16.9%) reported having DM at baseline. The overall incidence rate of hard braking events was 1.16 per 1000 miles. Adjusted for age, race/ethnicity, marital status, education level, annual household income, urbanicity, history of stroke, and number of medications, drivers with DM had a 10% increased rate of hard braking events compared to drivers without DM (adjusted IRR 1.10; 95% CI: 1.08, 1.12). Results of this study indicates that DM is associated with a significantly increased rate of hard braking events in older drivers, suggesting less safe driving. Driving safety should be incorporated into DM management and care programs.
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Abbassi, Younes, Youcef Ait-Amirat et Rachid Outbib. « Global modeling and simulation of vehicle to analyze the inertial parameters effects ». International Journal of Modeling, Simulation, and Scientific Computing 07, no 03 (23 août 2016) : 1650032. http://dx.doi.org/10.1142/s179396231650032x.
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This paper mainly studies the comparison of the global vehicle models and the effects of the inertial parameters due to the center of gravity (CG) positions when we consider that the vehicle has only one CG. This paper proposes a new nonlinear model vehicle model which considers both unsprung mass and sprung mass CG. The CG positions and inertial parameters effects are analyzed in terms of the published vehicle dynamics models. To this end, two 14 degree-of-freedom (DOF) vehicle models are developed and compared to investigate the vehicle dynamics responses due to the different CG height and inertial parameters concepts. The proposed models describe simultaneously the vehicle motion in longitudinal, lateral and vertical directions as well as roll, pitch and yaw of the vehicle about corresponding axis. The passive and active moments and the forces acting on the vehicle are also described and they are considered as a direct consequence of acceleration, braking and steering maneuvers. The proposed model [Formula: see text] takes both the CG of sprung mass, unsprung mass and total vehicle mass into account. The second model [Formula: see text] assumes that the vehicle is one solid body which has a single CG as reported in majority of literature. The two vehicle models are compared and analyzed to evaluate vehicle ride and handling dynamic responses under braking/acceleration and cornering maneuvers. Simulation results show that the proposed model [Formula: see text] could offer analytically some abilities and driving performances, as well as improved roll and pitch in a very flexible manner compared to the second model [Formula: see text].
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Hu, Qiang-Qiang, et Yong-Liang Yu. « The hydrodynamic effects of undulating patterns on propulsion and braking performances of long-based fin ». AIP Advances 12, no 3 (1 mars 2022) : 035319. http://dx.doi.org/10.1063/5.0083912.
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Bio-inspired long-based undulating fin propulsion is commonly employed in biological autonomous underwater vehicles (BAUVs), while the hydrodynamic characteristics of various undulating patterns are different. To investigate what kind of undulating pattern has outstanding propulsion or braking performance for BAUVs in directional maneuvers, undulations with four basic undulating patterns are numerically examined under the Open-source Field Operation And Manipulation environment at the Reynolds number of 5 × 102, 5 × 103, and 5 × 104, corresponding to viscous, transitional, and inertial flow regimes, respectively. The study is conducted at various non-dimensional phase speeds c (0.5–2.0, normalized by incoming flow speed) at a constant maximum amplitude of 0.08 and a wavelength of 0.5 (both are normalized by the fin cord length) to imitate the long-based fin. The numerical results indicate that the undulating fin motion with the amplitude envelope gradually increasing from the anterior part to the posterior (conical sinusoidal wave) part may be preferable for thrust generation; undulating with the amplitude envelope increasing from the anterior part to the mid part and decreasing toward the posterior (fusiform sinusoidal wave) presents the superior braking performance when the phase speed is low enough. Moreover, the influence of undulating patterns on the wake structure is analyzed. Through further comparative analysis for propulsion and braking performances, the results obtained here may have instructional significance to the propulsion mechanism in bionic design.
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Zhang, Jiaxu, et Jing Li. « Adaptive backstepping sliding mode control for wheel slip tracking of vehicle with uncertainty observer ». Measurement and Control 51, no 9-10 (28 août 2018) : 396–405. http://dx.doi.org/10.1177/0020294018795321.
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The wheel slip tracking control is the basis of automatic braking control systems, and the accurate tracking for the desired wheel slip in the presence of lumped uncertainty is a vital guarantee of automatic braking control systems reliable operation. Therefore, an adaptive backstepping sliding mode control approach with radial basis function neural network is proposed to design the nonlinear robust wheel slip controller based on a quarter-vehicle model with lumped uncertainty. The radial basis function neural network as the uncertainty observer can effectively reduce the chattering of sliding mode by estimating the lumped uncertainty, and the adaptive law for the unknown weight vector of radial basis function neural network is derived by Lyapunov-based method. The influence of changes in tire sideslip angle and camber angle on the tire -road friction coefficient acts as an unknown scaling factor, and the adaptive law for the unknown scaling factor is derived via Lyapunov-based method. Then, the performance of the proposed controller is verified through simulations of various maneuvers on a full-vehicle dynamics simulation software.
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Noonan, T. Zach, Pnina Gershon, Bruce Mehler et Bryan Reimer. « Characterizing the use of Tesla’s Auto Lane Change Feature in Driver-Initiated Maneuvers ». Proceedings of the Human Factors and Ergonomics Society Annual Meeting 66, no 1 (septembre 2022) : 1442–46. http://dx.doi.org/10.1177/1071181322661262.
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Tesla auto lane change is a feature within Autopilot (AP) – a collection of automated driving features designed to assist the driver with automatic steering and adaptive cruise control. In order to determine how drivers engage in maneuvers performed automatically by AP, 5,154 manual and automated lane change events along with video, system data, and vehicle kinematics were extracted from over 691 hours of naturalistic driving from 19 different drivers. Findings indicate that drivers performed manual lane changes more frequently than auto lane changes despite the use of Autopilot being more prevalent than manual driving on motorways. Auto lane changes occurred at higher speed and were associated with fewer acceleration and braking events and narrower distributions of kinematic characteristics. The lower frequency and kinematic variability in auto lane changes may suggest that drivers use this feature in a limited set of circumstances.
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Qian, Yubin, Song Feng, Wenhao Hu et Wanqiu Wang. « Obstacle avoidance planning of autonomous vehicles using deep reinforcement learning ». Advances in Mechanical Engineering 14, no 12 (décembre 2022) : 168781322211396. http://dx.doi.org/10.1177/16878132221139661.
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Obstacle avoidance path planning in a dynamic circumstance is one of the fundamental problems of autonomous vehicles, counting optional maneuvers: emergency braking and active steering. This paper proposes emergency obstacle avoidance planning based on deep reinforcement learning (DRL), considering safety and comfort. Firstly, the vehicle emergency braking and lane change processes are analyzed in detail. A graded hazard index is defined to indicate the degree of the potential risk of the current vehicle movement. The longitudinal distance and lateral waypoint models are established, including the comfort deceleration and stability coefficient considerations. Simultaneously, a fuzzy PID controller is installed to track to satisfy the stability and feasibility of the path. Then, this paper proposes a DRL process to determine the obstacle avoidance plan. Mainly, multi-reward functions are designed for different collisions, corresponding penalties for longitudinal rear-end collisions, and lane-changing side collisions based on the safety distance, comfort reward, and safety reward. Apply a special DRL method-DQN to release the planning program. The difference is that the long and short-term memory (LSTM) layer is utilized to solve incomplete observations and improve the efficiency and stability of the algorithm in a dynamic environment. Once the policy is practiced, the vehicle can automatically perform the best obstacle avoidance maneuver in an emergency, improving driving safety. Finally, this paper builds a simulated environment in CARLA and is trained to evaluate the effectiveness of the proposed algorithm. The collision rate, safety distance difference, and total reward index indicate that the collision avoidance path is generated safely, and the lateral acceleration and longitudinal velocity satisfy the comfort requirements. Besides, the method proposed in this paper is compared with traditional DRL, which proves the beneficial performance in safety and efficiency.
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Braghin, Francesco, et Edoardo Sabbioni. « A Dynamic Tire Model for ABS Maneuver Simulations ». Tire Science and Technology 38, no 2 (1 juin 2010) : 137–54. http://dx.doi.org/10.2346/1.3428971.
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Abstract Due to the dimensions of the tire-road contact area, transients in a tire last approximately 0.1 s. Thus, in the case of abrupt maneuvers such as ABS braking, the use of a steady-state tire model to predict the vehicle’s behavior would lead to significant errors. Available dynamic tire models, such as Pacejka’s MF-Tire model, are based on steady-state formulations and the transient behavior of the tire is included by introducing a first order differential equation of relevant quantities such as the slip angle and the slippage. In these differential equations the most significant parameter used to describe the transient behavior is the so-called relaxation length, i.e., the distance traveled by the tire to settle to a new steady-state condition once perturbated. Usually this parameter is assumed to be constant.
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Liu, Xiaobo, Lijuan Lai, You Kong et Scott Le Vine. « Protected Turning Movements of Noncooperative Automated Vehicles : Geometrics, Trajectories, and Saturation Flow ». Journal of Advanced Transportation 2018 (2018) : 1–12. http://dx.doi.org/10.1155/2018/1879518.
Texte intégralRésumé :
This study is the first to quantify throughput (saturation flow) of noncooperative automated vehicles when performing turning maneuvers, which are critical bottlenecks in arterial road networks. We first develop a constrained optimization problem based on AVs’ kinematic behavior during a protected signal phase which considers both ABS-enabled and wheels-locked braking, as well as avoiding encroaching into oncoming traffic or past the edge-of-receiving-lane. We analyze noncooperative (“defensive”) behavior, in keeping with the Assured Clear Distance Ahead legal standard to which human drivers are held and AVs will likely also be for the foreseeable future. We demonstrate that, under plausible behavioral parameters, AVs appear likely to have positive impacts on throughput of turning traffic streams at intersections, in the range of +0.2% (under the most conservative circumstances) to +43% for a typical turning maneuver. We demonstrate that the primary mechanism of impact of turning radius is its effect on speed, which is likely to be constrained by passenger comfort. We show heterogeneous per-lane throughput in the case of “double turn lanes.” Finally, we demonstrate limited sensitivity to crash-risk criterion, with a 4% difference arising from a change from 1 in 10,000 to 1 in 100,000,000. The paper concludes with a brief discussion of policy implications and future research needs.
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Khussein, Yu M., et O. V. Yanchetskyy. « PERSPECTIVE METHODS OF DIVERGENCE OF VESSELS AND ANALYSIS OF THEIR EFFICIENCY ». Scientific Bulletin Kherson State Maritime Academy 1, no 22 (2020) : 54–63. http://dx.doi.org/10.33815/2313-4763.2020.1.22.054-063.
Texte intégralRésumé :
The article is devoted to the analysis of the most perspective and effective locally-independent methods of divergence of vessels for forming of the system of the automatic warning of collisions, providing safety of perspective autonomous vessels. Development of method of estimation of efficiency of methods of divergence of vessels, which characterizes the degree of safety of completion of process of divergence of vessels, is offered, since the moment of discovery of situation of dangerous rapprochement. The stages of process of decision-making divergence of vessels of necessity are considered at their rapprochement and choice of strategy of divergence. It is shown that a decision-making process contains the following stages: control of environment, including relative position and parameters of relative motion, exposure of situation of rapprochement of vessels, estimation of degree of danger of rapprochement and choice of strategy of divergence. Analytical expressions for formalization of the offered stages of process of decision-making divergence of vessels of necessity are resulted. It is shown that depending on the degree of danger of situation of rapprochement, it is necessary to choose strategy of divergence, coming co-ordination of maneuvers of the drawn together vessels from, foreseen ColReg. Thus character of maneuver of divergence is also determined by the value of situation indignation. As a rule, application of standard maneuver of divergence is foreseen, and in the situation of excessive rapprochement of vessels, in order to avoid the collision it is necessary to use the maneuver of urgent divergence. As the index of efficiency of the analytical collision avoidance systems vessels probability of safe completion of process of divergence, which is work of probabilities of successful finish of stages of process of decision-making on the choice of strategy of divergence, is offered. For the system of the automatic warning of collisions the methods of divergence with one dangerous target are offered by the change of course or speed of ship and with two dangerous targets by the combined maneuver of the repeated change of course of ship. After the preliminary analysis the perspective most effective methods of the mentioned types of maneuvers of divergence were offered. For the operative choice of parameters of maneuver of divergence of ship with a target the regions of impermissible values of parameters of deviation and region of acceptability parameters of deviation and output are offered. For the case of choice of maneuver of divergence of ship by the decline of speed the active or passive braking offers the method of forming of region of impermissible speeds and calculation of its scopes. In the situation of dangerous rapprochement of ship with two targets for the operative choice of parameters of maneuver of divergence of ship in work it is suggested to form the region of acceptability successive courses of deviation.
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Trom, J. D., J. L. Lopez et M. J. Vanderploeg. « Modeling of a Mid-Size Passenger Car Using a Multibody Dynamics Program ». Journal of Mechanisms, Transmissions, and Automation in Design 109, no 4 (1 décembre 1987) : 518–23. http://dx.doi.org/10.1115/1.3258830.
Texte intégralRésumé :
This paper presents a multibody model of a passenger car and correlates the model with experimental data. Included in the model is a simple load-leveling control algorithm for controlling low frequency roll and pitch. The objectives of this paper are: to evaluate the effectiveness of vehicle modeling using a multibody dynamics program; to demonstrate multibody modeling techniques for complex suspension systems without the use of bushing models; and to demonstrate the feasibility of implementing control algorithms in multibody dynamics programs. The paper concludes that using multibody dynamics programs can be an effective method to model ride, handling, and braking of wheeled vehicles. The model presented in this paper shows good correlation in both the linear and nonlinear ranges for most maneuvers.