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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

IRIS: Intelligent Roadway Image Segmentation

Brown, Ryan Charles 23 June 2014 (has links)
The problem of roadway navigation and obstacle avoidance for unmanned ground vehicles has typically needed very expensive sensing to operate properly. To reduce the cost of sensing, it is proposed that an algorithm be developed that uses a single visual camera to image the roadway, determine where the lane of travel is in the image, and segment that lane. The algorithm would need to be as accurate as current lane finding algorithms as well as faster than a standard k- means segmentation across the entire image. This algorithm, named IRIS, was developed and tested on several sets of roadway images. The algorithm was tested for its accuracy and speed, and was found to be better than 86% accurate across all data sets for an optimal choice of algorithm parameters. IRIS was also found to be faster than a k-means segmentation across the entire image. IRIS was found to be adequate for fulfilling the design goals for the algorithm. IRIS is a feasible system for lane identification and segmentation, but it is not currently a viable system. More work to increase the speed of the algorithm and the accuracy of lane detection and to extend the inherent lane model to more complex road types is needed. IRIS represents a significant step forward in the single camera roadway perception field. / Master of Science
12

Desenvolvimento de sistema de navegação autônoma por GNSS. / Development of autonomous navigation system through GNSS.

Gonçalves, Luiz Felipe Sartori 15 April 2011 (has links)
Veículos autônomos são objeto de crescente estudo em todo o mundo. Face à Engenharia de Transportes, é tema que deve provocar uma revolução nas próximas décadas, pois é concreta a tendência ao uso destes veículos na sociedade. Podem se citar como grandes beneficiados a segurança, a logística, o fluxo de trânsito, o meio ambiente e também os portadores de deficiências. Com o objetivo de fazer um veículo atingir um ponto com coordenadas conhecidas de forma autônoma, uma plataforma veicular terrestre em escala foi utilizada, a qual recebeu um sistema computacional micro controlado e tecnologias para proporcionar mobilidade através de motores elétricos para tração e servo-motores para direcionamento; posicionamento por satélite através de receptor GNSS e bússola eletrônica para orientação; sensoriamento por ultra-som para evitar colisões; e comunicação sem fio, a fim de se realizar remotamente monitoramento e instrução em tempo real através de um aplicativo para computador pessoal (PC). Foi desenvolvido um algoritmo de navegação que, fazendo uso dos recursos disponíveis, proporcionou autonomia ao veículo, de forma a navegar para pontos com coordenadas conhecidas sem controle humano. Os testes realizados visaram avaliar a capacidade de autonomia do veículo, a trajetória de navegação realizada e a acurácia de chegada aos pontos de destino. O veículo foi capaz de atingir os pontos em todos os testes realizados, sendo considerado funcional seu algoritmo de navegação e também os sistemas de mobilidade, posicionamento, sensoriamento e comunicação. / Autonomous vehicles are an on growing research target around the world. Face to Transports Engineering, it is a subject which is expected to make a revolution on the next decades. The great benefits are on security, logistic, traffic flow, environment and handicap. With the goal to make a vehicle navigate autonomously to known geodesics coordinates, a reduced scale terrestrial vehicular platform was used. This platform received a microcontrolled computational system and technologies to give it mobility, through electrical motors for traction and servo-motors for direction; satellite positioning, through a GNSS receiver and magnetic compass for orientation; ultrasound sensing in order to avoid collision; and wireless communication, in order to do remote monitoring and instruction at real time through a PC application. It was developed a navigation algorithm which, from the available resources, gave autonomy to the vehicle, in order to navigate to known geodesics coordinates without human control. The test set was intended to evaluate the autonomy capacity of the vehicle, the navigation trajectory that was done and the arrival accuracy to the destination points. The vehicle reached the destination points on all tests done, being evaluated as functional its navigation algorithm and also the mobility, positioning, sensing and communication systems.
13

Obemannade markfarkosters militära nytta inom området logistiktransporter : En studie riktad mot Försvarsmaktens motståndarläge i Afghanistan / Unmanned Ground Vehicles Military Use Within The Area Of Logistics Transportation : A study directed towards the Swedish Armed Forces enemy situation in Afghanistan

Lundberg, Johnny January 2012 (has links)
Obemannade markfarkoster är ännu ganska ovanliga i den svenska Försvarsmakten men borde kunna bli allt vanligare. UGV:er används traditionellt till att utföra smutsiga, tråkiga och farliga arbetsuppgifter. Kan de då vara användbara i Afghanistan mot den motståndare som FM möter där idag? I studien undersöker författaren möjligheterna för obemannade markfarkoster att bidra med militär nytta inom området logistiktransporter. De obemannade transportfordonen kan från grunden utgöras av standardlastbilar i FM som har utrustats med så kallade UGV-kit. Dessa UGV-kit har till uppgift att göra standardfordonen fjärrstyrda, autonoma eller både och. Samma princip gäller för eskortfordonen som följer med till stöd för logistiktransporten, en Galt ska exempelvis kunna agera UGV. Den irreguljära och lågteknologiska motståndaren använder ofta IED:er vid eldöverfall vilket har gjort landsvägstransporter till riskfylld verksamhet för personal ute på vägarna. Personalsäkerhet är prioriterad verksamhet i Försvarsmakten och författarens antagande är att UGV:er kan bidra till att göra logistiktransporter och eskortförfaranden till mindre riskabel verksamhet. / Unmanned ground vehicles are still quite rare within in the Swedish Armed Forces but they should become more common. UGV´s are used traditionally for performing dirty, dull and dangerous tasks. Could they also be usefull against the enemy in Afghanistan that the Swedish Armed Forces are confronting there today? In this study the author investigates the possibilities for unmanned ground vehicles to contribute with military benefits to the area of logistics transportation. The unmanned transport vehicles can be ordinary standard trucks from the beginning which have been equipped with a so called UGV-kit. This UGV-kit´s task is to make the standard vehicles remotely controlled, autonomous or both. The same principle applies to the escorting vehicles, a Galt should for example also be able to act as a UGV. The irregular and low technology enemy often uses IED’s when attacking, which have made road transportation to hazardous activities for the personnel on the road. Personnel safety are prioritized activity within the Swedish Armed Forces, and the authors assumtion is that UGV’s can help making logistics transportation and escorting procedures in to less risky activities.
14

Desenvolvimento de sistema de navegação autônoma por GNSS. / Development of autonomous navigation system through GNSS.

Luiz Felipe Sartori Gonçalves 15 April 2011 (has links)
Veículos autônomos são objeto de crescente estudo em todo o mundo. Face à Engenharia de Transportes, é tema que deve provocar uma revolução nas próximas décadas, pois é concreta a tendência ao uso destes veículos na sociedade. Podem se citar como grandes beneficiados a segurança, a logística, o fluxo de trânsito, o meio ambiente e também os portadores de deficiências. Com o objetivo de fazer um veículo atingir um ponto com coordenadas conhecidas de forma autônoma, uma plataforma veicular terrestre em escala foi utilizada, a qual recebeu um sistema computacional micro controlado e tecnologias para proporcionar mobilidade através de motores elétricos para tração e servo-motores para direcionamento; posicionamento por satélite através de receptor GNSS e bússola eletrônica para orientação; sensoriamento por ultra-som para evitar colisões; e comunicação sem fio, a fim de se realizar remotamente monitoramento e instrução em tempo real através de um aplicativo para computador pessoal (PC). Foi desenvolvido um algoritmo de navegação que, fazendo uso dos recursos disponíveis, proporcionou autonomia ao veículo, de forma a navegar para pontos com coordenadas conhecidas sem controle humano. Os testes realizados visaram avaliar a capacidade de autonomia do veículo, a trajetória de navegação realizada e a acurácia de chegada aos pontos de destino. O veículo foi capaz de atingir os pontos em todos os testes realizados, sendo considerado funcional seu algoritmo de navegação e também os sistemas de mobilidade, posicionamento, sensoriamento e comunicação. / Autonomous vehicles are an on growing research target around the world. Face to Transports Engineering, it is a subject which is expected to make a revolution on the next decades. The great benefits are on security, logistic, traffic flow, environment and handicap. With the goal to make a vehicle navigate autonomously to known geodesics coordinates, a reduced scale terrestrial vehicular platform was used. This platform received a microcontrolled computational system and technologies to give it mobility, through electrical motors for traction and servo-motors for direction; satellite positioning, through a GNSS receiver and magnetic compass for orientation; ultrasound sensing in order to avoid collision; and wireless communication, in order to do remote monitoring and instruction at real time through a PC application. It was developed a navigation algorithm which, from the available resources, gave autonomy to the vehicle, in order to navigate to known geodesics coordinates without human control. The test set was intended to evaluate the autonomy capacity of the vehicle, the navigation trajectory that was done and the arrival accuracy to the destination points. The vehicle reached the destination points on all tests done, being evaluated as functional its navigation algorithm and also the mobility, positioning, sensing and communication systems.
15

Text Localization for Unmanned Ground Vehicles

Kirchhoff, Allan Richard 16 October 2014 (has links)
Unmanned ground vehicles (UGVs) are increasingly being used for civilian and military applications. Passive sensing, such as visible cameras, are being used for navigation and object detection. An additional object of interest in many environments is text. Text information can supplement the autonomy of unmanned ground vehicles. Text most often appears in the environment in the form of road signs and storefront signs. Road hazard information, unmapped route detours and traffic information are available to human drivers through road signs. Premade road maps lack these traffic details, but with text localization the vehicle could fill the information gaps. Leading text localization algorithms achieve ~60% accuracy; however, practical applications are cited to require at least 80% accuracy [49]. The goal of this thesis is to test existing text localization algorithms against challenging scenes, identify the best candidate and optimize it for scenes a UGV would encounter. Promising text localization methods were tested against a custom dataset created to best represent scenes a UGV would encounter. The dataset includes road signs and storefront signs against complex background. The methods tested were adaptive thresholding, the stroke filter and the stroke width transform. A temporal tracking proof of concept was also tested. It tracked text through a series of frames in order to reduce false positives. Best results were obtained using the stroke width transform with temporal tracking which achieved an accuracy of 79%. That level of performance approaches requirements for use in practical applications. Without temporal tracking the stroke width transform yielded an accuracy of 46%. The runtime was 8.9 seconds per image, which is 44.5 times slower than necessary for real-time object tracking. Converting the MATLAB code to C++ and running the text localization on a GPU could provide the necessary speedup. / Master of Science
16

Probability Based Path Planning of Unmanned Ground Vehicles for Autonomous Surveillance : Through World Decomposition and Modelling of Target Distribution

Liljeström, Per January 2022 (has links)
The interest in autonomous surveillance has increased due to advances in autonomous systems and sensor theory. This thesis is a preliminary study of the cooperation between UGVs and stationary sensors when monitoring a dedicated area. The primary focus is the path planning of a UGV for different initial intrusion alarms. Cell decomposition, i.e., spatial partitioning, of the area of surveillance was utilized, and the objective function is based on the probability of a present intruder in each cell. These probabilities were modeled through two different methods: ExpPlanner, utilizing an exponential decay function. Markov planner, utilizing a Markov chain to propagate the probabilities. The performance of both methods improves when a confident alarm system is utilized. By prioritizing the direction of the planned paths, the performances improved further. The Markov planner outperforms the ExpPlanner in finding a randomly walking intruder. The ExpPlanner is suitable for passive surveillance, and the Markov planner is suitable for ”aggressive target hunting”.
17

On Cooperative Surveillance, Online Trajectory Planning and Observer Based Control

Anisi, David A. January 2009 (has links)
The main body of this thesis consists of six appended papers. In the  first two, different  cooperative surveillance problems are considered. The second two consider different aspects of the trajectory planning problem, while the last two deal with observer design for mobile robotic and Euler-Lagrange systems respectively.In Papers A and B,  a combinatorial optimization based framework to cooperative surveillance missions using multiple Unmanned Ground Vehicles (UGVs) is proposed. In particular, Paper A  considers the the Minimum Time UGV Surveillance Problem (MTUSP) while Paper B treats the Connectivity Constrained UGV Surveillance Problem (CUSP). The minimum time formulation is the following. Given a set of surveillance UGVs and a polyhedral area, find waypoint-paths for all UGVs such that every point of the area is visible from  a point on a waypoint-path and such that the time for executing the search in parallel is minimized.  The connectivity constrained formulation  extends the MTUSP by additionally requiring the induced information graph to be  kept recurrently connected  at the time instants when the UGVs  perform the surveillance mission.  In these two papers, the NP-hardness of  both these problems are shown and decomposition techniques are proposed that allow us to find an approximative solution efficiently in an algorithmic manner.Paper C addresses the problem of designing a real time, high performance trajectory planner for an aerial vehicle that uses information about terrain and enemy threats, to fly low and avoid radar exposure on the way to a given target. The high-level framework augments Receding Horizon Control (RHC) with a graph based terminal cost that captures the global characteristics of the environment.  An important issue with RHC is to make sure that the greedy, short term optimization does not lead to long term problems, which in our case boils down to two things: not getting into situations where a collision is unavoidable, and making sure that the destination is actually reached. Hence, the main contribution of this paper is to present a trajectory planner with provable safety and task completion properties. Direct methods for trajectory optimization are traditionally based on a priori temporal discretization and collocation methods. In Paper D, the problem of adaptive node distribution is formulated as a constrained optimization problem, which is to be included in the underlying nonlinear mathematical programming problem. The benefits of utilizing the suggested method for  online  trajectory optimization are illustrated by a missile guidance example.In Paper E, the problem of active observer design for an important class of non-uniformly observable systems, namely mobile robotic systems, is considered. The set of feasible configurations and the set of output flow equivalent states are defined. It is shown that the inter-relation between these two sets may serve as the basis for design of active observers. The proposed observer design methodology is illustrated by considering a  unicycle robot model, equipped with a set of range-measuring sensors. Finally, in Paper F, a geometrically intrinsic observer for Euler-Lagrange systems is defined and analyzed. This observer is a generalization of the observer proposed by Aghannan and Rouchon. Their contractivity result is reproduced and complemented  by  a proof  that the region of contraction is infinitely thin. Moreover, assuming a priori bounds on the velocities, convergence of the observer is shown by means of Lyapunov's direct method in the case of configuration manifolds with constant curvature. / QC 20100622 / TAIS, AURES
18

Interaction Design for Remote Control of Military Unmanned Ground Vehicles

Saleh, Diana January 2021 (has links)
The fast technology development for military unmanned ground vehicles (UGVs) has led to a considerable demand to explore the soldier’s role in an interactive UGV system. This thesis explores how to design interactive systems for UGVs for infantry soldiers in the Swedish Armed Force. This was done through a user-centered design approach in three steps; (1) identifying the design drivers of the targeted military context through qualitative observations and user interviews, (2) using the design drivers to investigate concepts for controlling the UGV, and (3) create and evaluate a prototype of an interactive UGV system design. Results from interviews indicated that design drivers depend on the physical and psychological context of the intended soldiers. In addition, exploring the different concepts showed that early conceptual designs helped the user express their needs of a non-existing system. Furthermore, the results indicate that an interactive UGV system does not necessarily need to be at the highest level of autonomy in order to be useful for the soldiers on the field. The final prototype of an interactive UGV system was evaluated using a demonstration video, a Technology Acceptance Model (TAM), and semi-structured user interviews. Results from this evaluation suggested that the soldiers see the potential usefulness of an interactive UGV system but are not entirely convinced. In conclusion, this thesis argues that in order to design an interactive UGV system, the most critical aspect is the soldiers’ acceptance of the new system. Moreover, for soldiers to accept the concept of military UGVs, it is necessary to understand the context of use and the needs of the soldiers. This is done by involving the soldiers already in the conceptual design process and then throughout the development phases.

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