Este trabalho apresenta aspectos teóricos e práticos relevantes do desenvolvimento do Sistema de Navegação e Controle (SNC) a ser implementado em um Veículo Submarino Semi-Autônomo (VSSA), tipo não carenado e auto propelido, que está em desenvolvimento e construção na Escola Politécnica da USP, para a Petrobrás. Os três graus de liberdade horizontais são controlados para seguirem trajetórias pré-definidas, enviadas como sinais de referência para navegação por uma estação de apoio localizada na superfície, responsável pela guiagem do veículo. Os sinais de referência enviados são acústicos propagados pela água. A implementação física do SNC e o controle dos três graus de liberdade verticais não fazem parte do escopo deste trabalho. O SNC consiste em um controlador determinístico, um seguidor de trajetórias linear quadrático alimentado por um vetor de estados estimado assintoticamente. Por segurança, em caso de falha de algum sensor, e para filtrar ruídos nos sinais medidos, um estimador de estados de ordem plena é utilizado conjuntamente. Pela simplicidade de síntese e implementação, esta arquitetura de controle é considerada a melhor alternativa para capacitar o VSSA a executar os movimentos semi-autônomos desejados. As técnicas de controle utilizadas requerem a linearização do modelo matemático não-linear que descreve o comportamento dinâmico do veículo. O modelo é obtido de maneira simplificada. Os resultados são gerados por simulações com o modelo não-linear. / This work presents theoretical and practical aspects of the development of the Navigation and Control System (NCS) to be implemented into a Petrobras\' Semi-Autonomous Underwater Vehicle (SAUV), an open-frame and self-propelled type, which is being developed and built at Escola Politécnica of the University of São Paulo (EPUSP). The three horizontal Degrees-of-Freedom (DoF) are controlled so that they can follow a pre-defined trajectory sent as navigation reference signals to the NCS by a support ship, responsible for the guidance of the vehicle and placed on the ocean surface. Reference signals are sent as acoustic signals through the ocean water. The implementation and the control of the three vertical DoF are not in the scope of the present work. The NCS is based upon a deterministic controller, a Linear Quadratic (LQ) trajectory follower fed by an asymptotically estimated state vector, even though all the state variables are available by direct measurents. For safety, if some sensor fails, and for filtering noise on measured signals, a full-order state estimator is also designed. Since the LQ controller architecture is rather simple to design and implement, it was elected to control the SAUV manoeuvers. The control techniques require a linear model of the dynamics of the vehicle. Hence, a linearization procedure is applied to the system of nonlinear differential equations that describe the dynamic behavior of the SAUV. The results presented are provided by computer-aided simulations with the nonlinear model of the plant.

Modeling, system identification and controller design for a 16’ catamaran is described with the objective of enhanced operation in the presence of environmental disturbances including wind, waves and current. The vehicle is fully-actuated in surge, sway and yaw degrees of freedom. Analytical and experimental system identification is carried out to create a numerical model of the vehicle. A composite system of a Multiinput multi-output Proportional-Derivative (PD) controller and a nonlinear disturbance observer is used for station-keeping and transiting modes of operation. A waypoint transiting algorithm is developed to output heading and cross-track error from vehicle position and waypoints. A control allocation method is designed to lower azimuthing frequency and incorporate angle saturation and rate limits. Validation is achieved with improvement in simulation with the addition of the nonlinear observer. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Este trabalho apresenta aspectos teóricos e práticos relevantes do desenvolvimento do Sistema de Navegação e Controle (SNC) a ser implementado em um Veículo Submarino Semi-Autônomo (VSSA), tipo não carenado e auto propelido, que está em desenvolvimento e construção na Escola Politécnica da USP, para a Petrobrás. Os três graus de liberdade horizontais são controlados para seguirem trajetórias pré-definidas, enviadas como sinais de referência para navegação por uma estação de apoio localizada na superfície, responsável pela guiagem do veículo. Os sinais de referência enviados são acústicos propagados pela água. A implementação física do SNC e o controle dos três graus de liberdade verticais não fazem parte do escopo deste trabalho. O SNC consiste em um controlador determinístico, um seguidor de trajetórias linear quadrático alimentado por um vetor de estados estimado assintoticamente. Por segurança, em caso de falha de algum sensor, e para filtrar ruídos nos sinais medidos, um estimador de estados de ordem plena é utilizado conjuntamente. Pela simplicidade de síntese e implementação, esta arquitetura de controle é considerada a melhor alternativa para capacitar o VSSA a executar os movimentos semi-autônomos desejados. As técnicas de controle utilizadas requerem a linearização do modelo matemático não-linear que descreve o comportamento dinâmico do veículo. O modelo é obtido de maneira simplificada. Os resultados são gerados por simulações com o modelo não-linear. / This work presents theoretical and practical aspects of the development of the Navigation and Control System (NCS) to be implemented into a Petrobras\' Semi-Autonomous Underwater Vehicle (SAUV), an open-frame and self-propelled type, which is being developed and built at Escola Politécnica of the University of São Paulo (EPUSP). The three horizontal Degrees-of-Freedom (DoF) are controlled so that they can follow a pre-defined trajectory sent as navigation reference signals to the NCS by a support ship, responsible for the guidance of the vehicle and placed on the ocean surface. Reference signals are sent as acoustic signals through the ocean water. The implementation and the control of the three vertical DoF are not in the scope of the present work. The NCS is based upon a deterministic controller, a Linear Quadratic (LQ) trajectory follower fed by an asymptotically estimated state vector, even though all the state variables are available by direct measurents. For safety, if some sensor fails, and for filtering noise on measured signals, a full-order state estimator is also designed. Since the LQ controller architecture is rather simple to design and implement, it was elected to control the SAUV manoeuvers. The control techniques require a linear model of the dynamics of the vehicle. Hence, a linearization procedure is applied to the system of nonlinear differential equations that describe the dynamic behavior of the SAUV. The results presented are provided by computer-aided simulations with the nonlinear model of the plant.

Next-generation wireless cellular networks are morphing into a massive Internet of Things (IoT) environment that integrates a heterogeneous mix of wireless-enabled devices such as unmanned aerial vehicles (UAVs) and connected vehicles. This unprecedented transformation will not only drive an exponential growth in wireless traffic, but it will also lead to the emergence of new wireless service applications that substantially differ from conventional multimedia services. To realize the fifth generation (5G) mobile networks vision, a new wireless radio technology paradigm shift is required in order to meet the quality of service requirements of these new emerging use cases. In this respect, one of the major components of 5G is self-organized networks. In essence, future cellular networks will have to rely on an autonomous and self-organized behavior in order to manage the large scale of wireless-enabled devices. Such an autonomous capability can be realized by integrating fundamental notions of artificial intelligence (AI) across various network devices. In this regard, the main objective of this thesis is to propose novel self-organizing and AI-inspired algorithms for optimizing the available radio resources in next-generation wireless cellular networks. First, heterogeneous networks that encompass licensed and unlicensed spectrum are studied. In this context, a deep reinforcement learning (RL) framework based on long short-term memory cells is introduced. The proposed scheme aims at proactively allocating the licensed assisted access LTE (LTE-LAA) radio resources over the unlicensed spectrum while ensuring an efficient coexistence with WiFi. The proposed deep learning algorithm is shown to reach a mixed-strategy Nash equilibrium, when it converges. Simulation results using real data traces show that the proposed scheme can yield up to 28% and 11% gains over a conventional reactive approach and a proportional fair coexistence mechanism, respectively. In terms of priority fairness, results show that an efficient utilization of the unlicensed spectrum is guaranteed when both technologies, LTE-LAA and WiFi, are given equal weighted priorities for transmission on the unlicensed spectrum. Furthermore, an optimization formulation for LTE-LAA holistic traffic balancing across the licensed and the unlicensed bands is proposed. A closed form solution for the aforementioned optimization problem is derived. An attractive aspect of the derived solution is that it can be applied online by each LTE-LAA small base station (SBS), adapting its transmission behavior in each of the bands, and without explicit communication with WiFi nodes. Simulation results show that the proposed traffic balancing scheme provides a better tradeoff between maximizing the total network throughput and achieving fairness among all network ows compared to alternative approaches from the literature. Second, UAV-enabled wireless networks are investigated. In particular, the problems of interference management for cellular-connected UAVs and the use of UAVs for providing backhaul connectivity to SBSs are studied. Speci cally, a deep RL framework based on echo state network cells is proposed for optimizing the trajectories of multiple cellular-connected UAVs while minimizing the interference level caused on the ground network. The proposed algorithm is shown to reach a subgame perfect Nash equilibrium upon convergence. Moreover, an upper and lower bound for the altitude of the UAVs is derived thus reducing the computational complexity of the proposed algorithm. Simulation results show that the proposed path planning scheme allows each UAV to achieve a tradeoff between minimizing energy efficiency, wireless latency, and the interference level caused on the ground network along its path. Moreover, in the context of UAV-enabled wireless networks, a UAV-based on-demand aerial backhaul network is proposed. For this framework, a network formation algorithm, which is guaranteed to reach a pairwise stable network upon convergence, is presented. Simulation results show that the proposed scheme achieves substantial performance gains in terms of both rate and delay reaching, respectively, up to 3.8 and 4-fold increase compared to the formation of direct communication links with the gateway node. Overall, the results of the different proposed schemes show that these schemes yield significant improvements in the total network performance as compared to current existing literature. In essence, the proposed algorithms can also provide self-organizing solutions for several resource management problems in the context of new emerging use cases in 5G networks, such as connected autonomous vehicles and virtual reality headsets.

Philosophiae Doctor - PhD / Unmanned Aerial Vehicles (UAVs) have recently o ered signi cant technological achievements. The advancement in related applications predicts an extended need for automated data muling by UAVs, to explore high risk places, ensure e ciency and reduce the cost of various products and services. Due to advances in technology, the actual UAVs are not as expensive as they once were. On the other hand, they are limited in their ight time especially if they have to use fuel. As a result, it has recently been proposed that they could be assisted by the ground static sensors which provide information of their surroundings. Then, the UAVs need only to provide actions depending on information received from the ground sensors. In addition, UAVs need to cooperate among themselves and work together with organised ground sensors to achieve an optimal coverage. The system to handle the cooperation of UAVs, together with the ground sensors, is still an interesting research topic which would bene t both rural and urban areas. In this thesis, an e cient ground sensor network for optimal UAVs coverage is rst proposed. This is done using a clustering scheme wherein, each cluster member transmits its sensor readings to its cluster head. A more e cient routing scheme for delivering readings to cluster head(s) for collection by UAVs is also proposed. Furthermore, airborne sensor deployment models are provided for e cient data collection from a unique sensor/target. The model proposed for this consists of a scheduling technique which manages the visitation of UAVs to target. Lastly, issues relating to the interplay between both types of sensor (airborne and ground/underground) networks are addressed by proposing the optimal UAVs task allocation models; which take caters for both the ground networking and aerial deployment. Existing network and tra c engineering techniques were adopted in order to handle the internetworking of the ground sensors. UAVs deployment is addressed by adopting Operational Research techniques including dynamic assignment and scheduling models. The proposed models were validated by simulations, experiments and in some cases, formal methods used to formalise and prove the correctness of key properties.

This work concentrates on the topic of remote sensing using a multispectral imag-ing system for water management and agriculture applications. The platform, which is alight-weight inexpensive runway-free unmanned aerial vehicle (UAV), namely, AggieAir, ispresented initially. A major portion of this work focuses on the development of a light-weight multispectral imager payload for the AggieAir platform, called GhostFoto. Theimager is band-recongurable, covering both visual red, green, and blue (RGB) and nearinfrared (NIR) spectrum, and interfaced with UAV on-board computer. The developmentof the image processing techniques, which are based on the collected multispectral aerialimages, is also presented in this work. One application is to perform fully autonomous rivertracking for applications such as river water management. Simulation based on aerial mul-tispectral images is done to demonstrate the feasibility of the developed algorithm. Othereort is made to create a systematic method to generate normalized difference vegetationindex (NDVI) using the airborne imagery. The GhostFoto multispectral imaging systembased on AggieAir architecture is proven to be an innovative and useful tool.

Unmanned aerial vehicles and unmanned ground vehicles, or UAVs and UGVs respectively, currently perform a large variety of missions usually centered around reconnaissance. Because the platforms may vary for a particular type of mission--everything from small unmanned airplanes and remote control vehicles to large vehicles such as the Yamaha R-MAX helicopter and Hummer--flight and navigation controllers must be changed to allow proper control of the selected platform. Currently, controllers are designed and tested in MATLAB/SIMULINK, but then rewritten in C or Assembly for a specific target platform. When designing controllers in a programming language, changes are often tedious, so producing a working controller takes considerable time. MATLAB/SIMULINK provides a GUI interface and SIMULINK provides excellent testing capabilities, so changes may be quick and easy. However, no automated method for converting a simple controller, such as a PID for example, from MATLAB to implementation on a microcontroller has been presented in literature. To implement current in-house controllers designed in MATLAB/SIMULINK, a system consisting of Real-Time Workshop and a C compiler has been used to produce assembly code for a target microcontroller. To aid in verification of the controllers and C code produced by Real-Time Workshop targeted toward aerial platforms, an interface for the controllers in SIMULINK and a flight simulator (X-Plane) has been created. Thus the overall system allows for rapid changes and implementation on a variety of platforms as well as plug-in/plug-out capabilities in the field for diverse missions. Functionality and diversity of the system is demonstrated through testing of PID VTOL controllers in SIMULINK with X-Plane as well as implementation of UGV controllers onboard a small radio controlled truck.

University of Technology, Sydney. Faculty of Engineering. / The thesis focuses on issues of vehicle modelling incorporating wheel-terrain interaction and low-level control design taking into account uncertainties and input time delay. Addressing these issues is of significant importance in achieving persistent autonomy for outdoor UGVs, especially when navigating on unprepared terrains. The test-bed vehicle used for this research is retrofitted from an all-terrain 20-hp, 0.5-tonne vehicle. Its driveline system consists of an internal combustion engine, continuous variable transmission (CVT), gearbox, differential, chains, and eight wheels. The vehicle is driven in the skid-steering mode, which is popular for many off-road land-vehicle platforms. In this thesis, a comprehensive approach is proposed for modelling the driveline. The approach considers the difference in speed between two outputs of the differential and the turning mechanism of the vehicle. It describes dynamics of all components in the vehicle driveline in an integrated manner with the vehicle motion. Given a pattern of the throttle position, left and right braking efforts as the inputs, the dynamic behaviour of the wheels and other components of the UGV can be predicted. For controlling the vehicle at the low level, PID controllers are firstly used for all actuators. As many components of the vehicle exhibit nonlinearities and time delay, the large overshoots encountered in the outputs can lead to undesirable vehicle behaviours. To alleviate the problem, a novel control approach is proposed for suppression of overshoots resulting from PID control. Sliding mode control (SMC) is employed, for this, with time delay compensated by using an output predictor. As a result, the proposed approach can improve significantly system robustness and reduce substantially step response overshoot. Notably, the design is generic in that it can be applied for many dynamic processes. Knowledge of the interaction between the UGV and the terrain plays an important role in increasing its autonomy and securing the safety for off-road locomotion. In this regard, vehicle kinematic equations are combined with the theory of terramechanics for dynamic modelling of the interaction between the vehicle wheels and a variety of terrain types. Also, a fast algorithm is developed to enable online implementation. The novel interaction model takes into account the relationship between normal stresses, shear stresses, and shear displacement of the terrain that is in contact with the wheels in deriving the three-dimensional reaction forces. Finally, all modelling and control algorithms are integrated into a unique simulator for emulating the vehicle mobility characteristics. In particular, the wheel’s slip and rolling resistance can also be derived to provide useful information for closed-loop control when the UGV is navigating in an unknown environment. The simulator, as a tool for analysing the vehicle mobility, is helpful for further research on relevant topics such as traction control, safe and effective locomotion.

University of Technology, Sydney. Faculty of Engineering. / The thesis focuses on issues of vehicle modelling incorporating wheel-terrain interaction and low-level control design taking into account uncertainties and input time delay. Addressing these issues is of significant importance in achieving persistent autonomy for outdoor UGVs, especially when navigating on unprepared terrains. The test-bed vehicle used for this research is retrofitted from an all-terrain 20-hp, 0.5-tonne vehicle. Its driveline system consists of an internal combustion engine, continuous variable transmission (CVT), gearbox, differential, chains, and eight wheels. The vehicle is driven in the skid-steering mode, which is popular for many off-road land-vehicle platforms. In this thesis, a comprehensive approach is proposed for modelling the driveline. The approach considers the difference in speed between two outputs of the differential and the turning mechanism of the vehicle. It describes dynamics of all components in the vehicle driveline in an integrated manner with the vehicle motion. Given a pattern of the throttle position, left and right braking efforts as the inputs, the dynamic behaviour of the wheels and other components of the UGV can be predicted. For controlling the vehicle at the low level, PID controllers are firstly used for all actuators. As many components of the vehicle exhibit nonlinearities and time delay, the large overshoots encountered in the outputs can lead to undesirable vehicle behaviours. To alleviate the problem, a novel control approach is proposed for suppression of overshoots resulting from PID control. Sliding mode control (SMC) is employed, for this, with time delay compensated by using an output predictor. As a result, the proposed approach can improve significantly system robustness and reduce substantially step response overshoot. Notably, the design is generic in that it can be applied for many dynamic processes. Knowledge of the interaction between the UGV and the terrain plays an important role in increasing its autonomy and securing the safety for off-road locomotion. In this regard, vehicle kinematic equations are combined with the theory of terramechanics for dynamic modelling of the interaction between the vehicle wheels and a variety of terrain types. Also, a fast algorithm is developed to enable online implementation. The novel interaction model takes into account the relationship between normal stresses, shear stresses, and shear displacement of the terrain that is in contact with the wheels in deriving the three-dimensional reaction forces. Finally, all modelling and control algorithms are integrated into a unique simulator for emulating the vehicle mobility characteristics. In particular, the wheel’s slip and rolling resistance can also be derived to provide useful information for closed-loop control when the UGV is navigating in an unknown environment. The simulator, as a tool for analysing the vehicle mobility, is helpful for further research on relevant topics such as traction control, safe and effective locomotion.

This thesis has been written at Linköping University for the company Instrument Control Sweden AB (ICS). ICS is a small company located in Linköping that develops software and hardware for Unmanned Aerial Vehicles, UAV. At present, ICS has a fully functional autopilot called EasyPilot but they want to reduce the autopilot’s size to make it more attractive. The purpose of this thesis was to investigate if it was possible to reduce the size of the autopilot and how, in that case, it would be done. It was also necessary to examine whether the old processors should be replaced by new ones and how hard it would be to convert the old software to these new processors. To succeed with the goals many of the old components had to be changed for new, smaller ones. Some less necessary parts were also completely removed. The results showed that the size could be reduced quite a bit, exactly how much is hard to say since no PCB-layout were done. By doing some programming tests on the new components it could be shown that some parts of the old code could be reused on the new design. It was mainly algorithms and other calculations. However, a lot of new code still had to be written in order to successfully convert the old software to the new hardware.