Orientador: Prof. Dr. André Fenili / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Mecânica, 2016. / A medição da espessura de cascos de navios e outras estruturas submarinas por ultra-som criou uma nova e desafiante aplicação para robótica e apresenta vários desafios de controle gerados pela não linearidade, acoplamento de movimentos, incertezas nos parâmetros hidrodinâmicos e forças de perturbação. Este trabalho trata do controle de posição e atitude do Veículo Híbrido Submersível Operado de forma Remota (VHSOR) Proteo da Universidade Federal do ABC (São Paulo, Brasil). Neste trabalho aplicou-se a metodologia de control não linear State-Dependent Riccati Equation (SDRE) num VHSOR e obteve-se um controlador único que leva em consideração todos os estados da dinâmica do veículo, a não linearidade, o acoplamento e incertezas ao mesmo tempo. Também foram modeladas as perturbações externas com a intenção de verificar a capacidade do controlador para superar os problemas que aparecem em ambientes reais (forças e momentos externos gerados pelas correntes marinhas). Neste trabalho mostram-se os resultados obtidos das simulações numéricas do controlador desenvolvido e também os resultados obtidos dos experimentos em tanque de testes da plataforma robótica Proteo. Como parte do projeto de controle, neste trabalho realizou-se a programação da plataforma robótica Proteo provendo um sistema embarcado que faz aquisição de dados dos sensores, estima as variáveis de estado, calcula as ações de controle, ativa os atuadores, comunica a posição e velocidade (de traslação e rotação) à tripulação e recebe as referências em posição e velocidade (de traslação e rotação) enviadas desde um computador externo. Para este computador externo também realizou-se um programa que recebe sinais por meio de um Joystick e envia para o sistema embarcado na plataforma robótica Proteo. / The ultrasonic thickness measurements of ship hulls and other underwater structures has created a new and challenging application for robotics and poses several control challenges generated by non-linearity, coupling movements, uncertainties in the hydrodynamic parameters and disturbance forces. This work is on the development of position and attitude control of Hybrid Remotely Operated Vehicle (HROV) Proteo of the Universidade Federal do ABC (São Paulo, Brazil). In this work we used the nonlinear control methodology State-Dependent Riccati Equation (SDRE) as a unique control system, that takes into account all the states of the vehicle dynamic, non-linearities, coupling and uncertainty at the same time. Also, was modeled external disturbances with the intention to verify the ability of the control system to overcome a problem which is always encountered in real environments (external forces and moments generated by sea currents). This work shows the results obtained from numerical simulations of the developed controller and also the results of the tests of the robotic platform Proteo in a water tank. As part of the control design, in this work was carried out the programming of robotic platform Proteo providing an embedded system on it that makes data acquisition, estimate state variables, calculates control actions, active actuators, communicates position and velocity (of translation and rotation) to the crew and receives position and velocity references (of translation and rotation) from an external computer. For this external computer also was made a program that receives signals from a Joystick and sends to the embedded system in the robotic platform Proteo.

Orientadora: Profª. Drª. Elvira Rafikova / Coorientador: Prof. Dr. Magno Enrique Mendonza Meza / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Mecânica, Santo André, 2018.

This thesis deals with development of guidance laws for advanced applications. Two class of guidance problems, namely, impact angle constrained guidance and pulsed guidance for exo-atmospheric engagements, are considered here. Three impact angle constrained guidance schemes are developed using (i) Proportional navigation guidance (PNG), (ii) State Dependent Riccati Equation (SDRE) technique and (iii) geometric concepts, respectively. A collision course based pulsed guidance law is presented for exo-atmospheric interceptors. Proportional Navigation Guidance (PNG) law is the most widely used guidance law because of its ease of implementation and efficiency. However, in its original form, it achieves only a limited set of impact angles. A two stage PNG law is presented for achieving all impact angles against a stationary target. In the first phase of guidance, an orientation PNG command is used. The orientation navigation constant (N ) is a function of the initial engagement geometry and has a lower value (N less than 2). It is proved that following the orientation trajectory, the interceptor can switch to N = 2 and achieve the desired impact angle. Simulations, with a constant speed and with a realistic interceptor model, show successful interception of the target with all desired impact angles. Feedback implementation of the guidance law results in negligible errors in impact angle with uncompensated autopilot delays. The idea of a two-stage PNG law with impact angle constraint is further used to develop a guidance law for intercepting moving targets. Following the orientation trajectory, the interceptor can switch to N = 3 and achieve the desired impact angle. It is proved that the guidance achieves all impact angles in a surface-to-surface engagement scenario with receding and approaching targets, respectively. In a air-to-surface engagement scenario, it is proved that the guidance law achieves all impact angles in a deterministic set. Constant speed and realistic interceptor models are used for simulations. Results show negligible error in impact angle and miss distance for moving targets. The guidance law, in its feedback implementation form, achieves the desired impact angle for interceptors with delay and with a maneuvering target. The impact angle errors are low with negligible errors in miss distance. Next, the impact angle constrained guidance problem against a stationary target is solved as a non-linear regulator problem using the SDRE technique. The interceptor guidance problems are of finite time nature. As the main contribution of this part of the work, we solve a finite time interceptor guidance problem with infinite horizon SDRE formulation by choosing the state weighting matrix as a function of time-to-go. Numerical simulations are carried out both for a constant speed interceptor model and a realistic interceptor model. Simulations for both the models are carried out for various impact angles and firing angles. Robustness of the proposed guidance law with respect to autopilot lag is also verified by simulations. Results obtained show the efficiency of the SDRE approach for impact angle constrained missile guidance. A geometric guidance scheme is proposed for lateral interception of targets in a planar engagement scenario in the absence of line-of-sight rate information. A kill-band is defined for target initial positions capturable by an arc maneuver, followed by a straight line path by the interceptor. Guidance law for capturing targets inside the kill-band is presented and is further modified for targets outside the kill-band. Based on analytical studies on the kill-band, a guidance law is proposed for lateral interception of maneuvering targets. Simulations are carried with for typical low speed engagements. The concept of kill-band provides an inherent robustness to the proposed guidance law with respect to uncompensated system delays and target maneuver. As the final part of the work, an interceptor endgame pulsed guidance law for exoatmospheric engagements is derived by using the notion of collision heading. The proposed guidance law is derived in steps by (i) Obtaining the collision heading based on the collision triangle engagement geometry and then (ii) Computing the width of the pulse fired by the divert thruster to attain the collision heading. It is shown that this strategy is more effective than the existing zero effort miss (ZEM) based guidance laws for intercepting targets with higher heading angles off the nominal head-on collision course. A result on pulse firing sequence is also presented showing that firing pulses in quick succession results in minimum pulse widths and hence minimum control effort for a desired miss distance. Simulations are carried out for various engagement scenarios. Results show better miss-distance and divert thrust performance as compared to the existing ZEM based law.

Orientador: Prof. Dr. André Fenili / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Mecânica, Santo André, 2018.

This thesis addresses several aerospace guidance and decision making problems using both no cooperative and cooperative game theoretical solution concepts in the differential games framework. In the first part of the thesis, state dependent Riccati equation (SDRE) method has been extended to a zero-sum nonlinear differential games setting. This framework is used to study problems of intercepting a manoeuvring target, with and without terminal impact angle constraints, in the zero-sum differential games theory perspective. The guidance laws derived according to the proposed method are in closed from and online implementable. In the second part of the thesis, cooperative game theoretic concepts are applied to make a group of unmanned aerial vehicles (UAV) achieve rendezvous, in a given finite time horizon. An algorithm has been proposed that enables the UAVs to realize Nash bargaining solution. In this context, criteria for time consistency of a cooperative solution of nonzero-sum linear quadratic differential games have been studied. The problems where the UAVs try to achieve rendezvous by implementing cooperative game theoretic strategies, based on local information structure only, is also addressed.