Search results for "Autonomous vehicles"

Robust Discrete-Time Lateral Control of Racecars by Unknown Input Observers

2023

This brief addresses the robust lateral control problem for self-driving racecars. It proposes a discrete-time estimation and control solution consisting of a delayed unknown input-state observer (UIO) and a robust tracking controller. Based on a nominal vehicle model, describing its motion with respect to a generic desired trajectory and requiring no information about the surrounding environment, the observer reconstructs the total force disturbance signal, resulting from imperfect knowledge of the time-varying tire-road interface characteristics, presence of other vehicles nearby, wind gusts, and other model uncertainty. Then, the controller actively compensates the estimated force and as…

Traffic congestion reduction based on vehicle platoons and intelligent crossroads interactions

2021

Intersections are at the core of urban congestion. For more than a decade, new approaches based on autonomous and connected driving have been proposed. They aim to improve the performance of traffic control at intersections, by harnessing connectivity and driving automation (longitudinal control). These approaches have in common the fact that vehicles can negotiate together their right of way to use the conflicting space. However, they are different in terms of the way they share the space and optimization techniques. The challenge is to define the sequence of access of vehicles to the common space (which one goes first, which is the second, and so on) and the speed profile of vehicles to a…

ROAD SAFETY PERFORMANCES FROM MICRO-SIMULATION CONSIDERING AUTONOMOUS VEHICLES OPERATIONS

2019

Introduction of Autonomous Vehicles in road traffic will remove the impact of the human factor from the driver’s decision-making process, and will transform the criteria for road network design, road infrastructure administration, traffic modeling and assessment tools for road safety management. The paper presents a microsimulation-based approach for safety performance evaluation of roundabouts where different percentages of Autonomous Vehicles are mixed with Conventional Vehicles. The simulated vehicle trajectories exported from VISSIM were used as a basis to estimate traffic conflicts through the Surrogate Safety Assessment Model (SSAM) for a sample of European roundabouts. In order to be…

Racecar Longitudinal Control in Unknown and Highly-Varying Driving Conditions

2020

This paper focuses on racecar longitudinal control with highly-varying driving conditions. The main factors affecting the dynamic behavior of a vehicle, including aerodynamic forces, wheel rolling resistance, traction force resulting from changing tire-road interaction as well as the occurrence of sudden wind gusts or the presence of persistent winds, are considered and assumed to have unknown models. By exploiting the theory on delayed input-state observers and using measurement data about the vehicle and wheel speeds, a dynamic filter that allows the online reconstruction of the above-mentioned unknown time-varying quantities is derived. Moreover, by exploiting the notion of effective tir…

Safety Evaluation of Turbo-Roundabouts with and without Internal Traffic Separations Considering Autonomous Vehicles Operation

2021

The paper presents a microsimulation approach for assessing the safety performance of turbo-roundabouts where Cooperative Autonomous Vehicles “CAVs” have been introduced into the traffic mix alongside conventional vehicles “CVs”. Based on the analysis of vehicle trajectories from VISSIM and subsequent analysis of traffic conflicts through the Surrogate Safety Assessment Model (SSAM), the research aims to evaluate the safety benefits of turbo-roundabouts where the lanes are physically separated by raised curbs, compared to roundabouts without such curbs. The paper will then describe the methodological path followed to build VISSIM models of turbo-roundabouts with and without raised curbs in …

Integrated Simulation and Formal Verification of a Simple Autonomous Vehicle

2018

This paper presents a proof-of-concept application of an approach to system development based on the integration of formal verification and co-simulation. A simple autonomous vehicle has the task of reaching an assigned straight path and then follow it, and it can be controlled by varying its turning speed. The correctness of the proposed control law has been formalized and verified by interactive theorem proving with the Prototype Verification System. Concurrently, the system has been co-simulated using the Prototype Verification System and the MathWorks Simulink tool: The vehicle kinematics have been simulated in Simulink, whereas the controller has been modeled in the logic language of t…

Traffic Flow Variables Estimation: An Automated Procedure Based on Moving Observer Method. Potential Application for Autonomous Vehicles

2019

Abstract The estimation of traffic flow variables (flow, space mean speed and density) plays a fundamental role in highways planning and designing, as well as in traffic control strategies. Moving Observer Method (MOM) allows traffic surveys in a road, or in a road network. This paper proposes a novel automated procedure, called MOM-AP based on Moving Observer Method and Digital Image Processing (DIP) Technique able to automatically detect (without human observers) and calculate flow q, space mean speed vs and density k in case of stationary and homogeneous traffic conditions. In order to evaluate how reliable is the MOM-AP, an experiment has been carried out in a segment of one two-lane si…

Perceived benefits and constraints in vehicle automation: Data to assess the relationship between driver's features and their attitudes towards auton…

2019

This data article examines the association driver's features, perceptions and attitudes towards autonomous vehicles (AVs). The data was collected using a structured self-administrable and online-based questionnaire, applied to a full sample of 1205 Spanish drivers. The data contains 4 parts: the full set of bivariate correlations between study variables; descriptive statistics and graphical trends for each main study variable according to gender, age group and city/town size; and, finally, the dataset for further explorations in this regard. For more information, it is convenient to read the full article entitled “Perceived safety and attributed value as predictors of the intention to use a…

A mixed reality simulator for an autonomous delivery system using platooning

2021

Developments in the field of autonomous vehicles have encouraged research to innovate technology to solve everyday problems. E-commerce has been on the rise and, freighttransportation is considered an environmental nuisance, especially in the city centers. Electric vehicles have been proposed to reduce the environmental impact of transit vehicles. A package delivery system using a platoon of autonomous electric delivery vehicles and established public transport networks in cities can be employed to solve these problems. But autonomous vehicle testing is a point of concern for authorities and the public alike. This paper acknowledges this problem of validating the algorithms used to create a…

Safety evaluation of turbo roundabout with and without internal traffic separations considering autonomous vehicles operation

The paper presents a microsimulation approach for assessing the safety performance of turbo-roundabouts where Cooperative Autonomous Vehicles “CAVs” have been mixed with conventional vehicles “CVs”. Based on the analysis of vehicle trajectories from VISSIM and subsequent analysis of traffic conflicts through the Surrogate Safety Assessment Model (SSAM), the research aims to evaluate the safety benefits of turbo-roundabouts where the lanes are physically separated by raised curbs compared to roundabouts without curbs. The paper shall also lead to describe the methodological path followed to build VISSIM models of turboroundabout with and without raised curbs, to calibrate the simulation mode…