A BI-LEVEL SCHEME FOR ASSESSING THE IMPACT OF AIR TRANSPORTATION ON LOCAL DEVELOPMENT

An approach to assess the impact of the creation or expansion of an air transport infrastructure over regional development is proposed in this paper. Effective long term planning of this costly investment requires performing an overall analysis of socio-economic consequences through long term forecasting, scenario generation and risk analysis. One of main aspects of this task is related with the estimation of future demand over the modified transportation network which attends the considered region. The proposed approach makes use of two complementary models: One model is devoted to demand forecasting taking into account the modified accessibility of the multimodal transportation network, the other one defines the global transport supply according to a profit maximization behavior for the involved transport system. The demand forecasting process is based on an entropy maximization approach with flexible origin-destination levels to determine the intensity and the distribution of new origin-destination vectors. A two level solution technique considering vehicle flows at the first level and the payload/passengers flows at the second level is introduced. The proposed solution scheme is composed of an iterative process between the current solution for demand forecasting and the supply optimization problem: the entropy maximizing distribution problem provides the origin-destination matrix given a cost/capacity structure, while the supply optimization problem provides this cost/capacity structure resulting from the accessibility level, given the updated origin-destination vectors. The proposed approach is illustrated in the case of a fast developing rural agro-industrial area in central Brazil, where the consequences of the installation of a medium size airport are assessed.

A long term demand forecasting framework for a network of airports / Uma estrutura de previsão de demanda de longo prazo para uma rede de aeroportos

The study presented in this paper has been developed with the perspective of generating long term development plans for a network of domestic airports. As a first step towards this objective, the problem of generating long term predictions of demand for a network of domestic airports is considered. This is a step towards the objective of producing long term capacity investments plans allowing to manage adequately a network of airports. Then the different demand flows at airports which are relevant to characterize the need for new airport facilities and upgardes in capacity, are analysed and compatibility constraints between these flows introduced. An appraisal is realized about the basic data necessary to perform these network demand forecasts. A sequential scheme is proposed to generate in a coherent way predictions of the different dimensioning networks and airport flows. Passenger, freight and aircraft flows from and to external airports are also considered in this study

Análise de risco na inserção do planejamento urbano para instalação de empreendimentos de risco: aplicação no terminal de combustíveis / Risk analysis in the insertion of urban planning for the installation of risk ventures: application at the fuel terminal

Os estudos de riscos são instrumentos utilizados para identificar perigos, quantificar os riscos de acidentes e definir as estimativas da extensão de dano às áreas circunvizinhas à instalação.  Constituem assim, um conjunto de procedimentos e técnicas estruturadas para análise das atividades industriais perigosas, conforme destacado nos manuais de licenciamento de empreendimentos da CETESB (2011) e da FEPAM (2001). Nesse processo é contemplado o mapeamento das áreas sensíveis próximas ao projeto, assim como as potenciais regiões vulneráveis aos acidentes postulados. No entanto, incertezas e a variabilidade de resultados podem interferir na qualidade de resultados. Uma das principais fontes é a construção do cenário que depende da definição da fonte acidental, a avaliação da taxa de falhas, o período de ocorrência do evento e a escolha do modelo de simulação. A finalidade da pesquisa foi demonstrar através do estudo quantitativo de risco de um empreendimento industrial a magnitude de impacto na área urbanaconsiderando diferentes cenários acidentais com materiais combustíveis. O cálculo do risco social e da curva de iso-risco foram desenvolvidos para especificar a importância da magnitude de impacto e demonstrar um modelo para uso o planejamento urbano e subsidiar os gestores público para avaliar empreendimentos próximops às áreas urbanas. O conhecimento dos possiveis cenários com cálculo do risco auxilia na elaboração de planos de gestão e ação eficazes sendo primordial para a redução dos índices de acidentes fatais em áreas vulneráveis

A two level non linear inverse control structure for rotorcraft trajectory tracking

International audienceThe purpose of this communication is to investigate the usefulness of the non linear inverse control approach to solve the trajectory tracking problem for a four rotor aircraft. After introducing simplifying assumptions, the flight dynamics equations for the four rotor aircraft are considered. A trajectory tracking control structure based on a two layer non linear inverse approach is then proposed. A supervision level is introduced to take into account the actuator limitations

A soft dynamic programming approach for on-line aircraft 4D-trajectory optimization

International audienceDuring the last decade, Flight Management Systems (FMS) have been introduced on board modern aircraft to reduce operational costs, and flight profiles have been optimized in order to minimize fuel and time-related costs. Today, the integration of next generation FMS in the future air traffic management environment requires the development of new capabilities and among them, on-line real time 4D-trajectory generation has become mandatory. This paper presents a method based on dynamic programming (DP) to generate optimal 4D-trajectories in the presence of multiple time constraints. Soft computing techniques are introduced to improve the DP oriented optimization process by on-line selection of the search space and by cutting down computation time in repetitive performance evaluations

On-Line Optimization for Fault Tolerant Flight Control

International audienceIn this communication the case in which an aerodynamic actuator failure occurs to an aircraft while it has to perform some guidance maneuver is considered. This problem is dealt with the reassignment of remaining operational actuators in order to perform the required maneuver while maintaining the structural integrity of the aircraft. Nonlinear Inverse Control technique is used to generate online nominal moments along the three axes of the aircraft. Taking into account all material and structural constraints as well as the redundant effects from other actuators, a mathematical programming problem to be solved on-line which related to control reallocation can be formulated. Solution techniques, based on dynamic neural networks, active set methods and interior point methods are discussed and the respective performances are compared

Zero-gravity atmospheric flight by robust nonlinear inverse dynamics

International audienceZero gravity flights can be obtained for short periods with common subsonic aircraft. Thus, many valuable experiments and otherwise expensive training can be achieved at low cost. This note considers the design of an autopilot flight control law to realize such a maneuver with a high degree of accuracy. Accurary is impaired by atmospheric turbulence, local aerodynamic perturbations, and thrust fluctuations on one side and by the limited knowledge about the aircraft mechanics that is used in the design of the contro laws on the other side

MPC Based Handling Qualities Assessment for a Transportation Aircraft with Failed Actuators

International audienceThe objective of this study is to contribute to the evaluation of the remaining handling qualities of a transportation aircraft in the situation in which some aerodynamic actuators have failed. The maneuverability issue is in this study concentrated on the control of the three rotations along the main axis of a transportation aircraft. The solution approach adopted here is to perform at first an off-line study using a realistic flight simulation model of the aircraft to design a controller for the deflection of the remaining actuators with the objective of performing in a nominal way the considered reference maneuvers. When the control objective cannot be achieved, downgraded handling qualities are identified. The offline controller design approach follows the main steps of classical Model Predictive Control (MPC). The remaining of this paper describes the way this control approach has been developed to produce a useful tool to estimate the remaining handling qualities of an aircraft with failed actuators

Airline fleet assignment : a state of the art

International audienceWith the hard competitive environment of the air transportation sector, airlines have to cope with more and more complex and large optimization problems at planning and operations levels, especially concerning the fleet management. One of the major tasks consists in assigning profitable aircraft type to each flight, given the sets of flights and aircraft of an airline. The assignment has to meet a large variety of requirements and has to deal with the complementary objectives of maximizing revenue (by matching seat capacity to passenger demand) and minimizing costs (such as fuel, maintenance operations, airport gating ?) over the operated network. In this communication a state of the art relative to the fleet assignment models adopted in the Operations Research literature, is proposed. The different models are compared in terms of applicability to real life problems in a short term operational context. Side problems such as maintenance planning and crew assignment are also considered while performances such as robustness to common perturbations or to strong disruptions are of interest