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Authors
Advisor(s)
Abstract(s)
O mercado dos pequenos UAVs (unmanned aerial vehicle) está claramente em crescimento graças
à sua versatilidade aliada a um baixo custo e segurança de utilização.
O objetivo principal desta dissertação foi o de desenvolver um sistema que procurasse aumentar
a segurança destas pequenas aeronaves. Para que isto fosse possível incrementou-se um sistema
na aeronave que protegesse a sua estrutura fazendo a proteção do envelope de voo, e um outro
que detetasse possíveis falhas nos atuadores das superfícies de controlo, funcionando os dois de
maneira integrada.
Para a proteção do envelope de voo foi usada uma técnica anteriormente estudada por outros
autores a limitação de controlo dada à aeronave, limitando desta forma o movimento da mesma
e a possível saída dos seus limites físicos estruturais. A deteção de falhas no movimento das
superfícies de controlo foi alcançada com recurso a filtros de Kalman estendidos, uma técnica
bastante reconhecida para previsão do estado atual de um sistema dinâmico tendo por base
medições de estados anteriores, contendo sinais bastante ruído normalmente. Assim será possível
encontrar anomalias no sistema. Estas anomalias podem ser caracterizadas como diferenças
consideráveis nestes dois valores, o estimado pelos filtros de Kalman e o real, aquele que é dado
como como controlo.
Todo o trabalho foi desenvolvido com recurso ao software Matlab e Simulink. Primeiramente foi
construído um subsistema que simulasse o comportamento de uma aeronave e de seguida foram
desenvolvidos os subsistemas de proteção do envelope de voo e outro de deteção de falhas nos
atuadores das superfícies de controlo.
Os resultados obtidos foram satisfatórios e o sistema comportou-se como era esperado. O sistema
detetou facilmente as falhas nos atuadores introduzidas nas simulações para efeitos de estudo,
contudo não conseguiu fazer a atribuição das respetivas probabilidades de falha como era
esperado. Conseguiu adaptar o seu controlo consoante os atuadores onde essas falhas ocorriam.
Concluindo, é expectável que numa situação real estes dois subsistemas o de proteção do envelope
de voo e o detetor de falhas nos atuadores se complementem, e que em conjunto ofereçam uma
boa alternativa para um incremento de segurança neste tipo de aeronaves, para que no futuro se
possam reduzir os acidentes neste tipo de aviação e assim aumentar a segurança associada.
The market for small UAVs (unmanned aerial vehicle) is clearly growing thanks to their versatility, combined with low cost and safety of use. The main objective of this dissertation was to develop a system that sought to increase the safety of these small aircraft. To make this possible, a system was implemented on the aircraft that would protect its structure, protecting the flight envelope, and another one that would detect possible failures in the control surface actuators, both working in an integrated manner. For the protection of the flight envelope, a technique previously studied by other authors was used, which was the control limitation given to the aircraft, limiting its movement and the possible departure from its physical structural limits. The detection of faults in the movement of the control surfaces was achieved using extended Kalman filters, a well-recognized technique for predicting the current state of a dynamic system based on measurements of previous states, with these signals normally having a lot of noise. This will make it possible to find anomalies in the system. These anomalies can be characterized as considerable differences in these two values, the one estimated by Kalman filters and the real one, which is given as a control. All work was developed using Matlab and Simulink software. First, a subsystem was built to simulate the behaviour of an aircraft and then the flight envelope protection subsystems and another one for fault detection in the control surface actuators were developed. The results obtained were satisfactory and the system behaved as expected. The system easily detected the failures in the actuators introduced in the simulations for study purposes, however it was not able to assign the respective failure probabilities as expected. It managed to adapt its control depending on the actuators where these failures occurred. In conclusion, it is expected that in a real situation these two subsystems, the flight envelope protection, and the actuator failure detector, complement each other and that together they offer a good alternative for an increase in safety in this type of aircraft so that in the future can reduce accidents in this type of aviation and in this way increase the associated safety.
The market for small UAVs (unmanned aerial vehicle) is clearly growing thanks to their versatility, combined with low cost and safety of use. The main objective of this dissertation was to develop a system that sought to increase the safety of these small aircraft. To make this possible, a system was implemented on the aircraft that would protect its structure, protecting the flight envelope, and another one that would detect possible failures in the control surface actuators, both working in an integrated manner. For the protection of the flight envelope, a technique previously studied by other authors was used, which was the control limitation given to the aircraft, limiting its movement and the possible departure from its physical structural limits. The detection of faults in the movement of the control surfaces was achieved using extended Kalman filters, a well-recognized technique for predicting the current state of a dynamic system based on measurements of previous states, with these signals normally having a lot of noise. This will make it possible to find anomalies in the system. These anomalies can be characterized as considerable differences in these two values, the one estimated by Kalman filters and the real one, which is given as a control. All work was developed using Matlab and Simulink software. First, a subsystem was built to simulate the behaviour of an aircraft and then the flight envelope protection subsystems and another one for fault detection in the control surface actuators were developed. The results obtained were satisfactory and the system behaved as expected. The system easily detected the failures in the actuators introduced in the simulations for study purposes, however it was not able to assign the respective failure probabilities as expected. It managed to adapt its control depending on the actuators where these failures occurred. In conclusion, it is expected that in a real situation these two subsystems, the flight envelope protection, and the actuator failure detector, complement each other and that together they offer a good alternative for an increase in safety in this type of aircraft so that in the future can reduce accidents in this type of aviation and in this way increase the associated safety.
Description
Keywords
Controlo Falha Limite Matlab Proteção do Envelope de Voo Segurança Simulink