517 research outputs found

    LeggedWalking on Inclined Surfaces

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    The main contribution of this MS Thesis is centered around taking steps towards successful multi-modal demonstrations using Northeastern's legged-aerial robot, Husky Carbon. This work discusses the challenges involved in achieving multi-modal locomotion such as trotting-hovering and thruster-assisted incline walking and reports progress made towards overcoming these challenges. Animals like birds use a combination of legged and aerial mobility, as seen in Chukars' wing-assisted incline running (WAIR), to achieve multi-modal locomotion. Chukars use forces generated by their flapping wings to manipulate ground contact forces and traverse steep slopes and overhangs. Husky's design takes inspiration from birds such as Chukars. This MS thesis presentation outlines the mechanical and electrical details of Husky's legged and aerial units. The thesis presents simulated incline walking using a high-fidelity model of the Husky Carbon over steep slopes of up to 45 degrees.Comment: Masters thesi

    Routing UAVs to Co-Optimize Mission Effectiveness and Network Performance with Dynamic Programming

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    In support of the Air Force Research Laboratory\u27s (AFRL) vision of the layered sensing operations center, command and control intelligence surveillance and reconnaissance (C2ISR) more focus must be placed on architectures that support information systems, rather than just the information systems themselves. By extending the role of UAVs beyond simply intelligence, surveillance, and reconnaissance (ISR) operations and into a dual-role with networking operations we can better utilize our information assets. To achieve the goal of dual-role UAVs, a concrete approach to planning must be taken. This research defines a mathematical model and a non-trivial deterministic algorithmic approach to determining UAV placement to support ad-hoc network capability, while maintaining the valuable service of surveillance activities

    Flight controller synthesis via deep reinforcement learning

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    Traditional control methods are inadequate in many deployment settings involving autonomous control of Cyber-Physical Systems (CPS). In such settings, CPS controllers must operate and respond to unpredictable interactions, conditions, or failure modes. Dealing with such unpredictability requires the use of executive and cognitive control functions that allow for planning and reasoning. Motivated by the sport of drone racing, this dissertation addresses these concerns for state-of-the-art flight control by investigating the use of deep artificial neural networks to bring essential elements of higher-level cognition to bear on the design, implementation, deployment, and evaluation of low level (attitude) flight controllers. First, this thesis presents a feasibility analyses and results which confirm that neural networks, trained via reinforcement learning, are more accurate than traditional control methods used by commercial uncrewed aerial vehicles (UAVs) for attitude control. Second, armed with these results, this thesis reports on the development and release of an open source, full solution stack for building neuro-flight controllers. This stack consists of a tuning framework for implementing training environments (GymFC) and firmware for the world’s first neural network supported flight controller (Neuroflight). GymFC’s novel approach fuses together the digital twinning paradigm with flight control training to provide seamless transfer to hardware. Third, to transfer models synthesized by GymFC to hardware, this thesis reports on the toolchain that has been released for compiling neural networks into Neuroflight, which can be flashed to off-the-shelf microcontrollers. This toolchain includes detailed procedures for constructing a multicopter digital twin to allow the research and development community to synthesize flight controllers unique to their own aircraft. Finally, this thesis examines alternative reward system functions as well as changes to the software environment to bridge the gap between simulation and real world deployment environments. The design, evaluation, and experimental work summarized in this thesis demonstrates that deep reinforcement learning is able to be leveraged for the design and implementation of neural network controllers capable not only of maintaining stable flight, but also precision aerobatic maneuvers in real world settings. As such, this work provides a foundation for developing the next generation of flight control systems

    INTEROPERABILITY FOR MODELING AND SIMULATION IN MARITIME EXTENDED FRAMEWORK

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    This thesis reports on the most relevant researches performed during the years of the Ph.D. at the Genova University and within the Simulation Team. The researches have been performed according to M&S well known recognized standards. The studies performed on interoperable simulation cover all the environments of the Extended Maritime Framework, namely Sea Surface, Underwater, Air, Coast & Land, Space and Cyber Space. The applications cover both the civil and defence domain. The aim is to demonstrate the potential of M&S applications for the Extended Maritime Framework, applied to innovative unmanned vehicles as well as to traditional assets, human personnel included. A variety of techniques and methodology have been fruitfully applied in the researches, ranging from interoperable simulation, discrete event simulation, stochastic simulation, artificial intelligence, decision support system and even human behaviour modelling

    Top-Down & Bottom-Up Approaches to Robot Design

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    This thesis presents a study of different engineering design methodologies and demonstrates their effectiveness and limitations in actual robot designs. Some of these methods were blended together with focus on providing an easily interpreted project design flow while implementing more bottom-up, or feedback, elements into the design methodology. Typically design methods are learned through experience, and design taught in academia aims to shape and formalize previous experience. Usually, inexperienced engineers are taught approaches resembling the Verein Deutscher Ingenieure (VDI) 2221 process. This method presented by the Association of German Engineers in 2006 is regarded as the general system design process. This introductory process is largely left open to interpretation, and it is often unclear when to implement feedback in the design process. The objective of this thesis is to investigate the roles of top-down and bottom-up processes, and how to integrate them in the robot design methodology. The proposed approach utilizes several components from existing design methods. There are three main conditional loops within the proposed approach. The first loop focuses on defining the problem in a top-down manner through logical decomposition, defining technical requirements, researching solutions, and conducting a trade study. These four steps are done iteratively until reaching the bottom of the system, the most primitive components. This is followed by a modeling and analysis loop. This works from the bottom to the top of the design in preparation for manufacturing and validation. The final loop of the proposed approach focuses on validation and verification. The testing and manufacturing involved allows for alterations to the design to fulfill the original technical requirements. These three loops occur until a proof of concept is achieved. The proposed method is intended to be applied iteratively. The first pass of the method results in a proof of concept, while the second results in a preproduction prototype, and the third in a production model. This assembly of design elements provides a project flow that leaves little to be interpreted and is suitable for small design teams while still flexible enough to be applied to diverse robotics projects. This thesis provides three case studies analyzing the application of the hybrid design approach mentioned above to robotic system development. The first study showcases a complicated system design with a small development team. The second case is of simpler construction with a smaller developer team. This simpler case better demonstrates the benefits of this hybrid approach in robotic system development due to the comparatively higher speed at which the system matures. The third case study shows how this same proposed approach can be applied to the design of a bottom-up controlled swarm. These case studies are for future designers to reference as examples of the hybrid design methodology in application, and what can happen when there is a lack of feedback in design. This proposed hybrid design method can encourage design practices in new engineers that translate better to industrial applications, and therefore encourage faster integration of new engineers into established design engineering practices

    Aerial Vehicles

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    This book contains 35 chapters written by experts in developing techniques for making aerial vehicles more intelligent, more reliable, more flexible in use, and safer in operation.It will also serve as an inspiration for further improvement of the design and application of aeral vehicles. The advanced techniques and research described here may also be applicable to other high-tech areas such as robotics, avionics, vetronics, and space

    MODELLING VIRTUAL ENVIRONMENT FOR ADVANCED NAVAL SIMULATION

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    This thesis proposes a new virtual simulation environment designed as element of an interoperable federation of simulator to support the investigation of complex scenarios over the Extended Maritime Framework (EMF). Extended Maritime Framework is six spaces environment (Underwater, Water surface, Ground, Air, Space, and Cyberspace) where parties involved in Joint Naval Operations act. The amount of unmanned vehicles involved in the simulation arise the importance of the Communication modelling, thus the relevance of Cyberspace. The research is applied to complex cases (one applied to deep waters and one to coast and littoral protection) as examples to validate this approach; these cases involve different kind of traditional assets (e.g. satellites, helicopters, ships, submarines, underwater sensor infrastructure, etc.) interact dynamically and collaborate with new autonomous systems (i.e. AUV, Gliders, USV and UAV). The use of virtual simulation is devoted to support validation of new concepts and investigation of collaborative engineering solutions by providing a virtual representation of the current situation; this approach support the creation of dynamic interoperable immersive framework that could support training for Man in the Loop, education and tactical decision introducing the Man on the Loop concepts. The research and development of the Autonomous Underwater Vehicles requires continuous testing so a time effective approach can result a very useful tool. In this context the simulation can be useful to better understand the behaviour of Unmanned Vehicles and to avoid useless experimentations and their costs finding problems before doing them. This research project proposes the creation of a virtual environment with the aim to see and understand a Joint Naval Scenario. The study will be focusing especially on the integration of Autonomous Systems with traditional assets; the proposed simulation deals especially with collaborative operation involving different types of Autonomous Underwater Vehicles (AUV), Unmanned Surface Vehicles (USV) and UAV (Unmanned Aerial Vehicle). The author develops an interoperable virtual simulation devoted to present the overall situation for supervision considering also the sensor capabilities, communications and mission effectiveness that results dependent of the different asset interaction over a complex heterogeneous network. The aim of this research is to develop a flexible virtual simulation solution as crucial element of an HLA federation able to address the complexity of Extended Maritime Framework (EMF). Indeed this new generation of marine interoperable simulation is a strategic advantage for investigating the problems related to the operational use of autonomous systems and to finding new ways to use them respect to different scenarios. The research deal with the creation of two scenarios, one related to military operations and another one on coastal and littoral protection where the virtual simulation propose the overall situation and allows to navigate into the virtual world considering the complex physics affecting movement, perception, interaction and communication. By this approach, it becomes evident the capability to identify, by experimental analysis within the virtual world, the new solutions in terms of engineering and technological configuration of the different systems and vehicles as well as new operational models and tactics to address the specific mission environment. The case of study is a maritime scenario with a representation of heterogeneous network frameworks that involves multiple vehicles both naval and aerial including AUVs, USVs, gliders, helicopter, ships, submarines, satellite, buoys and sensors. For the sake of clarity aerial communications will be represented divided from underwater ones. A connection point for the latter will be set on the keel line of surface vessels representing communication happening via acoustic modem. To represent limits in underwater communications, underwater signals have been considerably slowed down in order to have a more realistic comparison with aerial ones. A maximum communication distance is set, beyond which no communication can take place. To ensure interoperability the HLA Standard (IEEE 1516 evolved) is adopted to federate other simulators so to allow its extensibility for other case studies. Two different scenarios are modelled in 3D visualization: Open Water and Port Protection. The first one aims to simulate interactions between traditional assets in Extended Maritime Framework (EMF) such as satellite, navy ships, submarines, NATO Research Vessels (NRVs), helicopters, with new generation unmanned assets as AUV, Gliders, UAV, USV and the mutual advantage the subjects involved in the scenario can have; in other word, the increase in persistence, interoperability and efficacy. The second scenario models the behaviour of unmanned assets, an AUV and an USV, patrolling a harbour to find possible threats. This aims to develop an algorithm to lead patrolling path toward an optimum, guaranteeing a high probability of success in the safest way reducing human involvement in the scenario. End users of the simulation face a graphical 3D representation of the scenario where assets would be represented. He can moves in the scenario through a Free Camera in Graphic User Interface (GUI) configured to entitle users to move around the scene and observe the 3D sea scenario. In this way, players are able to move freely in the synthetic environment in order to choose the best perspective of the scene. The work is intended to provide a valid tool to evaluate the defencelessness of on-shore and offshore critical infrastructures that could includes the use of new technologies to take care of security best and preserve themselves against disasters both on economical and environmental ones

    Aerial Robotics for Inspection and Maintenance

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    Aerial robots with perception, navigation, and manipulation capabilities are extending the range of applications of drones, allowing the integration of different sensor devices and robotic manipulators to perform inspection and maintenance operations on infrastructures such as power lines, bridges, viaducts, or walls, involving typically physical interactions on flight. New research and technological challenges arise from applications demanding the benefits of aerial robots, particularly in outdoor environments. This book collects eleven papers from different research groups from Spain, Croatia, Italy, Japan, the USA, the Netherlands, and Denmark, focused on the design, development, and experimental validation of methods and technologies for inspection and maintenance using aerial robots
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