Jules Ghislain Slama

A fuzzy logic approach for car-following modelling

In this communication, the classical car-following theory, which is based on intuitiveness and behavioural representation, is revisited from the point of view of cybernetics theory. Then, a new approach, based on fuzzy modelling, is proposed to estimate the main parameters of the basic car following model. This approach, contrarily to earlier fuzzy logic approaches, maintains the structure of the classical car-following model, limits its complexity and provides means to take into account the main parameters influencing the behaviour of the driver and allows a formal verification of local and global stability of the simulated traffic flow. So, after introducing a new approach based on cybernetics concepts for the modelling of car-following, which provides a theoretical basis for the basic model, the main concepts of fuzzy logic theory and of fuzzy modelling are briefly presented. Then a fuzzy estimation approach is proposed for the main parameters of the basic car-following model. Finally, simulation results making use of the proposed modelling approach are presented.

Motion planning on Mobile Robots using Differential Flatness

One solution for the motion planning in a nonholonomic vehicle, described as mobile robot, is made in this paper. Using the boundary conditions, the desired trajectory is parameterized in a polynomial by means of a point to point steering algorithm. The system is drove trough the trajectory, using the Differential Flatness properties, calculating the input values in order to perform the movement. Simulations and results of the study are presented.

Is DNL appropriate for airport noise zoning

The use of the DNL metric in airport noise zoning is based in the works of Schultz, that were later improved by Fidell. The basic idea is to use the percentage of highly annoyed people as a parameter to organize the area around airports. In urban zoning it is recommended to use the equivalent sound level LAEQ, which uses different criteria to day and night periods to define the land use. With regards to airport noise one may use LAD and LAN metrics which are the equivalent sound levels determined for day and night period, respectively. In this case, the maximum levels chosen to the establishment of the zoning are based on the land use. It is possible, through a simple equation, to determine the DNL level associated to a LAD, LAN pair. The inverse problem, however, has not a unique solution, once this relation depends on the number of daily and night flights of the airport. Thus, the use of DNL in airport noise zoning may lead to completely different results for different airports. Exemples are presented and discussed for two main brazilian airports: Recife and Congonhas.

Neural Inversion of Flight Guidance Dynamics

Differential flatness, a property of some dynamic systems which has been recognized only recently, has made possible the development of new tools to control complex nonlinear dynamic systems. Many dynamic nonlinear systems have been proved to be differentially flat. In this paper, it is shown that the inertial position coordinates of an aircraft can be considered as differential flat outputs for its flight guidance dynamics. Since this differential flatness property is implicit, a neural network is introduced, as a numerical device, to deal with the inversion of the guidance dynamics. Then, once conveniently structured and trained, a neural network is able to generate in real time directives to conventional autopilot systems so that a reference trajectory can be tracked. Numerical results relative to the training of the neural network and to trajectory tracking are displayed and discussed.

Neural Prediction of Aircraft Noise Levels Along a Flight Trajectory

Sustained increase in air transportation as well as urban encroachment have generated noise critical situations around airports. Then the prediction of the noise impact resulting from new departure/arrival procedures and new traffic patterns at airports gains more importance. Until recently this estimation has been performed on statistical grounds through the segmentation of nominal aircraft trajectories. This approach is in general not representative of the temporal dimension of the noise impacts over the airport surrounding population. To go beyond this limitation, a dynamical approach to noise impact estimation taking explicitly into consideration the operated 3D+T aircraft trajectory, is proposed in this communication. This is achieved by taking profit of the differential flatness property of the flight guidance dynamics of transportation aircraft, which allows through inversion to compute the corresponding thrust and aerodynamic conditions which are also responsible for aircraft noise generation. In numerical grounds this is achieved by building a neural network device which produces ground noise levels histories along the trajectories flown by aircraft. The proposed approach is partially validated using for comparison noise levels estimated from the Integrated Noise Model (INM). The proposed tool appears to be useful to analyze the noise impact of complex traffic scenarios including traffic dispersion phenomena.

A NEURAL ADAPTIVE APPROACH FOR RELATIVE GUIDANCE OF AIRCRAFT

ABSTRACT In this study a neural adaptive approach is examined for aircraft trajectory generation. The relative guidance of an aircraft, which is aimed to join in minimum time the track of a leader aircraft, is particularly considered. Neural networks are applied to generate on-line optimized aircraft trajectories associated to the current relative position. In a first place, the minimum time optimization problem is considered. Then the synthesis of a neural approximator of optimal trajectories is discussed. Trained neural networks are used in an adaptive manner to generate intent trajectories during operation. Finally simulation results involving two wide body aircraft are presented where the pursuit trajectory is generated with and without knowledge of the leading aircrafts flight plan.

SIMULAÇÕES DO RUÍDO DE AERONAVES DE CARGA PARA DIFERENTES RECEPTORES CRÍTICOS

O ruido aeroportuario produz varios efeitos adversos nos seres humanos, tais como incomodo, interferencias na comunicacao oral e no sono. Este estudo tem como objetivo analisar a influencia do ruido sobre o sono da populacao, especialmente a causada por avioes de carga, uma vez que sao aeronaves pesadas e barulhentas, com um grande numero de operacoes, pousos e decolagens durante a noite. Os percentuais de interrupcao do sono durante a passagem de n aeronaves serao calculados e estudos de analise de sensibilidade serao realizados considerando diferentes cenarios.