Teresa de Pedro

An RFID-based intelligent vehicle speed controller using active traffic signals.

These days, mass-produced vehicles benefit from research on Intelligent Transportation System (ITS). One prime example of ITS is vehicle Cruise Control (CC), which allows it to maintain a pre-defined reference speed, to economize on fuel or energy consumption, to avoid speeding fines, or to focus all of the driver’s attention on the steering of the vehicle. However, achieving efficient Cruise Control is not easy in roads or urban streets where sudden changes of the speed limit can happen, due to the presence of unexpected obstacles or maintenance work, causing, in inattentive drivers, traffic accidents. In this communication we present a new Infrastructure to Vehicles (I2V) communication and control system for intelligent speed control, which is based upon Radio Frequency Identification (RFID) technology for identification of traffic signals on the road, and high accuracy vehicle speed measurement with a Hall effect-based sensor. A fuzzy logic controller, based on sensor fusion of the information provided by the I2V infrastructure, allows the efficient adaptation of the speed of the vehicle to the circumstances of the road. The performance of the system is checked empirically, with promising results.

Autonomous vehicle based in cooperative gps and inertial systems

A system including Global Positioning Systems (GPS) and digital cartography is a good solution to carry out vehicles guidance. However, it has inconveniences like high sensibility to multipath and interference when the GPS signal is blocked by external agents. Another system is mandatory to avoid this error. This paper presents a cooperative system based on GPS and Inertial Navigation Systems (INS) for automated vehicle position. The control system includes a decision unit to choose which value is the correct. In case GPS is working at top precision, it takes the control. On the other part, GPS signal can be lost and inertial control system guides the car in this occasion. A third possibility is contemplated: we receive the signal from GPS but the accuracy is over one meter. Now, position value is obtained by means of both systems. Experimental results analyze two situations: guidance in an urban area where GPS signal can be occluded by buildings or trees during short time intervals and the possibility of loss of the signal in long time to simulate the circulation in tunnels. Good results have been observed in tests and it demonstrates how a cooperative system improves the automated vehicle guidance.

Modularity, adaptability and evolution in the AUTOPIA architecture for control of autonomous vehicles

Computer systems to carry out control algorithms on autonomous vehicles have been developed in recent years. However, the advances in peripheral devices allow connecting the actuator controllers to the control system by means of standard communication links (USB, CAN, Ethernet…).The goal is to permit the use of standard computers. In this paper, we present the evolution of AUTOPIA architecture and its modularity and adaptability to move the old system based on ISA controller cards to a new system with Ethernet and CAN connected controllers. The results show a comparison between both systems and the improved performance of the new system.

Autonomous driving manoeuvres in urban road traffic environment: a study on roundabouts

Abstract The highway and urban traffic safety has significantly been improved thanks to advanced development of Intelligent Transportation Systems technologies. However, some driving aspects have remained outside of this evolution or they are still in the development stage. Autonomous vehicle performance on roundabouts is one of these. In this paper, a simple and practical approach for the driverless control on roundabouts is described. Firstly, a description of a path planning is explained. Finally, a new concept for lateral control on roundabouts is introduced, taking into account entrances, exits and lane changes inside the roundabouts. The experiments have been tested in a 3D simulator that emulates the behaviour of driverless vehicle from the real world, – Cybercars. The results are promising, and leave the door open for future implementation in real vehicles.

Ultrasonic Sensors in Urban Traffic Driving-Aid Systems

Currently, vehicles are often equipped with active safety systems to reduce the risk of accidents, most of which occur in urban environments. The most prominent include Antilock Braking Systems (ABS), Traction Control and Stability Control. All these systems use different kinds of sensors to constantly monitor the conditions of the vehicle, and act in an emergency. In this paper the use of ultrasonic sensors in active safety systems for urban traffic is proposed, and the advantages and disadvantages when compared to other sensors are discussed. Adaptive Cruise Control (ACC) for urban traffic based on ultrasounds is presented as an application example. The proposed system has been implemented in a fully-automated prototype vehicle and has been tested under real traffic conditions. The results confirm the good performance of ultrasonic sensors in these systems.

Autonomous car fuzzy control modeled by iterative genetic algorithms

The techniques of Soft Computing are recognized as having a strong learning and cognition capability as well as good tolerance to uncertainty and imprecision. These properties allow them to be applied successfully to Intelligent Transportation Systems (ITS), a broad range of diverse technologies that designed to answer many transportation problems. The unmanned control of the steering wheel is one of the most important challenges faced by researchers in this area. This paper presents a method of automatically adjusting a fuzzy controller to manage the steering wheel of a mass-produced vehicle. Information about the state of the car while a human driver is handling it is captured and used to search, via genetic algorithms, for the best fit of an appropriate fuzzy controller. Evaluation of the fuzzy controller will take into account its adjustment to the human drivers actions and the absence of abrupt changes in its control surface, so that not only is the route tracking good, but the drive is smooth and comfortable for the vehicles occupants.

Control basado en PID inteligentes: aplicación al control de crucero de un vehículo a bajas velocidades

A pesar de sus limitaciones, la tecnica de control mas utilizada en el mundo industrial sigue siendo todavia hoy el control PID. En este articulo se presenta un nuevo enfoque, el control basado en PID inteligentes (i-PID), que aprovecha las virtudes que han hecho tan popular al PID, mejorando uno de sus puntos debiles: la perdida de prestaciones en presencia de terminos no-lineales o de dinamicas no modeladas. Para ilustrar las caracteristicas del i-PID, se ha probado su comportamiento en una aplicacion real, el control robusto de velocidad sobre un vehiculo experimental en entornos urbanos.

Making transport safer: V2V-based automated emergency braking system

An important goal in the field of intelligent transportation systems (ITS) is to provide driving aids aimed at preventing accidents and reducing the number of traffic victims. The commonest traffic accidents in urban areas are due to sudden braking that demands a very fast response on the part of drivers. Attempts to solve this problem have motivated many ITS advances including the detection of the intention of surrounding cars using lasers, radars or cameras. However, this might not be enough to increase safety when there is a danger of collision. Vehicle to vehicle communications are needed to ensure that the other intentions of cars are also available. The article describes the development of a controller to perform an emergency stop via an electro-hydraulic braking system employed on dry asphalt. An original V2V communication scheme based on WiFi cards has been used for broadcasting positioning information to other vehicles. The reliability of the scheme has been theoretically analyzed to estimate its performance when the number of vehicles involved is much higher. This controller has been incorporated into the AUTOPIA program control for automatic cars. The system has been implemented in Citroen C3 Pluriel, and various tests were performed to evaluate its operation.

Adelantamiento con vehiculos autónomos en carreteras de doble sentido

Research on cooperation and control among autonomous vehicles is in the vanguard of the Intelligent Transportation Systems (ITS). Some examples are the intersection maneuvers, Adaptive Cruise Control (ACC), and overtaking, among others. Overtaking requires special attention in dynamic environments, especially when there is a vehicle coming from the other direction on a two-way road. In this paper a decision algorithm, a communication system among three vehicles and a fuzzy logic control, to implement the overtaking maneuver are explained. Different use cases has been considered, they evaluate if to finish or to abort in a safe way the overtaking maneuver. The results show a good performance of the fuzzy control based in human knowledge for high risk maneuvers.

AUTOPIA program advances: how to automate the traffic?

Road transport fatalities are one of the major causes of death in developed countries, so the investigation in aid systems for vehicles to reduce these figures is nowadays an open field of research. With this final goal, AUTOPIA program has been working from 1996 in the development of aid driving systems and, specifically, in autonomous systems capable of replacing the driver in some specific tasks, reducing so, the dependence on the human driver. In this paper we present some of the most relevant advances achieved using commercial vehicles. To achieve this objective, prototype vehicles have been equipped with capabilities to permit it to act over the actuators of the vehicle autonomously. Several cooperative maneuvers have been developed during last years toward a final goal: an intelligent traffic control system.