The Avoiding Manoeuvre Against Aggregated Group of Obstacles Moving Around the Airplane

Successful avoidance of a mid air collision with moving obstacles depends on solutions of some most essential problems, e.g.: quick detection of an obstacle, verification whether detected obstacle is a critical one and making right decision on evasive manoeuvre. This decision – making process requires an appropriate identification of a threat’s nature, including whether detected obstacles should be treated as one aggregated group. Aggregation of obstacles moving in short distance one to the other is a typical case. The paper addresses also the case of inclusion the obstacle to the group objects moving in longer distances one to the other. The algorithm used for deciding whether a moving obstacle should be added to (aggregated with) a given group has been presented. A method for computing its characteristic parameters has been presented too. Selected scenarios of avoiding the aggregated group of moving obstacles have been simulated and results obtained illustrates problems considered.

An evasive manoeuvre, automatically controlled to avoid the one of a group of many obstacles moving in a vicinity of flying airplane

Detection of a collision threat and an appropriate decision on passing by an obstacle are necessary for solving the problem of collision avoidance in case of aircraft motion within the airspace. In the article a method for detecting a threat of collision with the obstacle is presented for the case of many moving objects appearing within the neighbourhood of the aircraft. The analysis of an algorithm for making a preliminary decision on avoiding a collision with more than one moving obstacle was carried out. The shape of a class of evasive trajectories was proposed, and its reliability was proved. Numerical simulations of flight were completed for the considered type of aircraft in aforementioned conditions. The scope of these simulations covered all phases of obstacle avoiding manoeuvre, including a return to a straight-line part of flight trajectory pre-planned before the start. Automatycznie sterowany manewr omijania jednej spośród grupy przeszkód poruszających się w otoczeniu lecącego samolotu Streszczenie: Do rozwiązania problemu unikania przeszkód przez poruszający się samolot w przestrzeni powietrznej niezbędne jest wykrycie zagrożenia kolizji oraz podjęcie właściwej decyzji o sposobie ominięcia przeszkody. W artykule przedstawiono sposób wykrywania niebezpieczeństwa zderzenia z przeszkodą dla przypadku, gdy w otoczeniu samolotu znajduje się wiele ruchomych obiektów. Przeprowadzono analizę algorytmu podejmowania wstępnych decyzji o sposobie unikania kolizji z więcej niż jedną ruchomą przeszkodą. Zaproponowano kształt klasy trajektorii manewru omijania i potwierdzono jej wykonalność na drodze symulacji numerycznej. Wykonano symulację numeryczną lotu przyjętego typu samolotu we wspomnianych warunkach. Zakres tych symulacji obejmował wszystkie fazy manewru omijania przeszkody, włącznie z powrotem do prostoliniowego odcinka lotu, stanowiącego fragment trasy zaplanowanej przed startem. Słowa kluczowe: unikanie przeszkód, systemy antykolizyjne, symulacja komputerowa, dynamika lotu

Influence of Vehicle Model Complexity in Autonomous Emergency Manoeuvre Planning

In this paper the effectiveness of an optimal reference manoeuvre is analysed w.r.t. the complexity of the vehicle model used within the optimal control algorithm. The optimal reference manoeuvre is computed by means of a Nonlinear Receding Horizon planning (NRHP) strategy which is based on a simplified vehicle model. The reference manoeuvre is tracked by a controller implemented on a low level faster loop. The system is able to perform autonomously lane change and obstacle avoidance manoeuvres by tracking the computed reference one. The quality of the performed manoeuvres depends on the reference manoeuvre and consequently on the vehicle model used by the NRHP. For manoeuvres with low or mild lateral accelerations reduced order models might yield realistic and reliable reference manoeuvres. However, critical conditions (e.g. evasive manoeuvre) require a manoeuvre planner able to catch highly non-linear vehicle dynamics that characterizes such situations. On the other hand, being the NRHP computational cost generally high and related to the number of equations of the mathematical model, a trade-off between computational efficiency and model complexity is required. The work analyses the reference manoeuvres produced by two vehicle models of increasing complexity used as reference within the NRHP. Optimal planner performance evaluation on evasive manoeuvre in critical conditions will be presented with simulations results.