Cooperative Throttle and Brake Fuzzy Control for ACC+Stop&Go Maneuvers

The authors are with the Industrial Computer Science Department, Instituto de Automática Industrial (CSIC), 28500 Madrid, SpainThe goal that a car be driven autonomously is far in the future and probably unreachable, but as a first step in that direction, adaptive cruise control (ACC) and Stop&Go maneuver systems are being developed. These kind of controllers adapt the speed of a car to that of the preceding one (ACC) and get the car to stop if the lead car stops. This paper presents one such system and related experiments performed on a real road with real cars. The driving system gets its input via an RTK DGPS device and communicates its positions to one another via a wireless local area network link. It outputs signals controlling the pressure on the throttle and brake pedals. The control system is based on fuzzy logic, which is considered best to deal with processes as complex as driving. Two mass produced Citroën Berlingo electric vans have been instrumented, providing them with computer controlled actuators over the brake and the throttle to achieve human-like driving. The results of the experiments show that the behavior of the vehicles is very close to human and that they adapt to driving incidences, increasing the safety of the driving and permitting cooperation with manually driven cars.This work was supported in part by the Spanish Ministry of Education under Grant ISAAC CICYT DPI2002-04064-C05-02, by the Spanish Ministry of Public Works under Grant COPOS BOE 280 22/11/2002, and by the Res. 22778, Citroën España S.A. under Contract “Adquirir nuevos conocimientos sobre la introducción de las tecnologías de la información en el mundo del automóvil y para difundirlos en los ámbitos científicos, empresariales y comerciales (AUTOPIA),” and by Cybecars-2 Project UE-STREP 28062, 6th Framework Programme, 2006.Peer reviewe

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 Citroën C3 Pluriel, and various tests were performed to evaluate its operation

Experimental Application of Hybrid Fractional-Order Adaptive Cruise Control at Low Speed

International audienceThis brief deals with the design and experimen-tal application of a hybrid fractional adaptive cruise control (ACC) at low speeds. First, an improved fractional-order cruise control (CC) is presented for a commercial Citroën C3 prototype—which has automatic driving capabilities—at low speeds, which considers a hybrid model of the vehicle. The quadratic stability of the system is proved using a frequency domain method. Second, ACC maneuvers are implemented with two different distance policies using two cooperating vehicles— one manual, the leader, and the other, automatic—also at very low speeds. In these maneuvers, the objective is to maintain a desired interdistance between the leader and follower vehi-cles, i.e., to perform a distance control—with a proportional differential (PD) controller in this case—in which the previously designed fractional-order CC is used for the speed control. Simulation and experimental results, obtained in a real circuit, are given to demonstrate the effectiveness of the proposed control strategies. Index Terms— Adaptive cruise control (ACC), fractional-order control (FOC), hybrid system and control, stability

Comparing fuzzy and intelligent PI controllers in stop-and-go manoeuvres

The aim of this work was twofold: on the one hand, to describe a comparative study of two intelligent control techniques-fuzzy and intelligent proportional-integral (PI) control, and on the other, to try to provide an answer to an as yet unsolved topic in the automotive sector-stop-and-go control in urban environments at very low speeds. Commercial vehicles exhibit nonlinear behavior and therefore constitute an excellent platform on which to check the controllers. This paper describes the design, tuning, and evaluation of the controllers performing actions on the longitudinal control of a car-the throttle and brake pedals-to accomplish stop-and-go manoeuvres. They are tested in two steps. First, a simulation model is used to design and tune the controllers, and second, these controllers are implemented in the commercial vehicle-which has automatic driving capabilities-to check their behavior. A stop-and-go manoeuvre is implemented with the two control techniques using two cooperating vehicles

Low-Speed Cooperative Car-Following Fuzzy Controller for Cybernetic Transport Systems

International audience— This paper describes the development of a Coop-erative Adaptive Cruise Control (CACC) for the future urban transportation system at low-speed. The control algorithm was evaluated using two Cybecars as prototype vehicles. A longitu-dinal response model for the vehicles was developed to design the CACC system. The control algorithm was implemented on a fuzzy logic-based controller that has been tuned to minimize a cost function in order to get a trade-off between a proper car-following gap error and the smoothness of the control signal. The controller was firstly tested in simulation using the developed model. Then, the CACC was implemented in two Cybecars to validate the controller performance in real scenarios