H∞ Orbital Control of a Space Vehicle on a Low Earth Orbit

• Autor(a) principal: Dente, Pedro Miguel Mariano
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.6/10330
• topic: Arrasto Atmosférico; Controlador H∞; J2; Órbita Terrestre Baixa; Veículo Espacial; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica

A Low Earth Orbit (LEO) is the trajectory of a space vehicle such as a satellite, missile or space shuttle relative to the Earth with an altitude of 1,500 km or less. Keplerian orbits only take in account the gravitational forces between bodies, however, in real life applications there are a lot of perturbations that alter the initial trajectory or the “mathematical ideal orbit” of the space vehicle. The perturbations analyzed in this dissertation were the atmospheric drag and the oblateness of the Earth (J2). It is necessary to control this trajectory in order to adjust the orbital elements so that the space vehicle can operate in the surroundings of the initial orbit and perform its mission adequately. There are many types of controllers for these space vehicles like the Linear-Quadratic Regulator (LQR), the Sliding Mode Control (SMC), the Linear Matrix Inequality (LMI) and the H-infinity (H∞) Controller. It is essential to find the best type of controller for each specific mission. Considering the inherent limitations of the methods mentioned above, the H8 Controller was judged to be the most suitable for this application under certain conditions. The focus of this dissertation is the development of an H8 robust controller that can successfully alter the trajectory of a space vehicle with perturbations, so that it follows a referenced Keplerian trajectory with the same initial conditions.