31 research outputs found

    Coordination and navigation of heterogeneous MAV-UGV formations localized by a 'hawk-eye'-like approach under a model predictive control scheme

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    n approach for coordination and control of 3D heterogeneous formations of unmanned aerial and ground vehicles under hawk-eye-like relative localization is presented in this paper. The core of the method lies in the use of visual top-view feedback from flying robots for the stabilization of the entire group in a leader–follower formation. We formulate a novel model predictive control-based methodology for guiding the formation. The method is employed to solve the trajectory planning and control of a virtual leader into a desired target region. In addition, the method is used for keeping the following vehicles in the desired shape of the group. The approach is designed to ensure direct visibility between aerial and ground vehicles, which is crucial for the formation stabilization using the hawk-eye-like approach. The presented system is verified in numerous experiments inspired by search-and-rescue applications, where the formation acts as a searching phalanx. In addition, stability and convergence analyses are provided to explicitly determine the limitations of the method in real-world applications

    Attractor dynamics approach to joint transportation by autonomous robots: theory, implementation and validation on the factory floor

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    This paper shows how non-linear attractor dynamics can be used to control teams of two autonomous mobile robots that coordinate their motion in order to transport large payloads in unknown environments, which might change over time and may include narrow passages, corners and sharp U-turns. Each robot generates its collision-free motion online as the sensed information changes. The control architecture for each robot is formalized as a non-linear dynamical system, where by design attractor states, i.e. asymptotically stable states, dominate and evolve over time. Implementation details are provided, and it is further shown that odometry or calibration errors are of no significance. Results demonstrate flexible and stable behavior in different circumstances: when the payload is of different sizes; when the layout of the environment changes from one run to another; when the environment is dynamice.g. following moving targets and avoiding moving obstacles; and when abrupt disturbances challenge team behavior during the execution of the joint transportation task.- This work was supported by FCT-Fundacao para a Ciencia e Tecnologia within the scope of the Project PEst-UID/CEC/00319/2013 and by the Ph.D. Grants SFRH/BD/38885/2007 and SFRH/BPD/71874/2010, as well as funding from FP6-IST2 EU-IP Project JAST (Proj. Nr. 003747). We would like to thank the anonymous reviewers, whose comments have contributed to improve the paper

    A summary of the users perspective of LANDSAT-D and reference document of LANDSAT users

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    There are no author-identified significant results in this report

    Clatsop County natural hazard mitigation plan : Report for Clatsop County

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    425 pp. Bookmarks modified by UO. Maps, charts, tables, figures, appendices. Published August, 2008. Captured February 11, 2009.The plan goals describe the overall direction that the participating jurisdiction's agencies, organizations, and citizens can take toward mitigating risk from natural hazards. They are as follows: protect life; minimize damage to public and private buildings and infrastructure; reduce economic loss; decrease disruption to critical services; protect natural and cultural resources; increase education and awareness of the risks and hazards in Clatsop County; increase cooperation and collaboration among County partners. [From the Plan]"This Natural Hazard Mitigation Plan was developed through a regional partnership funded by the Federal Emergency Management Agency's Pre- Disaster Mitigation Competitive Grant Program. The Oregon Coast Region grant was awarded to support the development of natural hazard mitigation plans for the region. The region's planning process utilized a four-phased planning process, plan templates and plan development support provided by the Partnership for Disaster Resilience at the University of Oregon.

    Callaborating to Improve Community Resiliency to Natural Disasters

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    https://digitalcommons.memphis.edu/govpubs-tn-advisory-commission-intergovernmental-relations-miscellaneous-reports/1011/thumbnail.jp

    Urban in Nature: Yosemite, Cars, and California\u27s Cities, 1913–1970

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    The impacts of national parks do not stop at their borders, and neither should their histories. Located less than a day’s drive from California’s biggest cities, Yosemite National Park remains a product of their combined influences. “Urban in Nature” is a relational history of the park and its nearby metropolitan areas like Merced (70 miles away), Berkeley (180), San Francisco (200), and Los Angeles (300). Since the advent of the automobile Yosemite has been a mirror of the state’s urban areas, rather than an escape from them. Passenger cars drove Yosemite’s urbanization in two interconnected ways. Firstly, increasing amounts of tourist traffic in the early 1900s forced National Park Service personnel to construct increasingly sophisticated built environment; this process is especially evident in Yosemite Valley, a spectacular chasm containing waterfalls, sheer cliffs, and—most importantly—tens of thousands of humans at any given time. Secondly, automobiles served as cross-pollinators between the park and urban California, facilitating a statewide exchange of ideas, architecture, and political allegiances. In both its physical form and its connections to other cities, Yosemite Valley became “urban in nature.” This study expands the political, economic, and cultural significance of areas that are often considered escapes from urban industrial society. I argue that, on the contrary, places like Yosemite are integral parts of the world outside their gates. It has become common to bemoan the level of development in America’s national parks, but I argue that we must acknowledge their connections with urban spaces in order to reach a more nuanced understanding of the interdependency between nature and civilization

    All That is Solid Melts into Air Travel: Environments, Technologies, and the Modern Nation at Trans-Canada Air Lines

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    This dissertation explores how Trans-Canada Air Lines (1937-1965) built, maintained, and subverted what I call the “modern envirotechnical nation” in its public-facing discourse. Euro-Canadian national identity in the nineteenth and twentieth centuries has been rooted in both the environment—Canada was imagined as very big and very cold—and communications technologies that allowed settlers to traverse long distances and transcend harsh climates. At first blush, these appear both contradictory and self-reinforcing. How can we, for example, celebrate Canada’s size while at the same time technologically annihilating distance? Although clearly commensurate, environmental and technological nationalisms must work for that commensurability, especially in modern, high modern, and late/postmodern Canada. I refer to this work, as well as the discursive products of that work, the “modern envirotechnical nation.” I work mainly with the airline’s public-facing material, including advertisements, publicity images, media reports, press releases, and speeches by executives and sympathetic politicians to explore this phenomenon. As a state airline, TCA was beholden to taxpayers and worked with government advertisers, which meant that it forwarded something of a state-sanctioned narrative of environment, technology, and nation and used its discourse to express larger anxieties about what it meant to be a modern Canadian. TCA worked throughout its first two decades to maintain the modern Canadian envirotechnical nation in this material. Ultimately, it was unable to reconcile the role of air travel in creating new relationships between space, place, time, and the everyday experience of mobility with this paradigm as high-powered jets took Canadians faster and farther than the “modern envirotechnical nation” would allow. I treat air travel in Canada as a high-modern megaproject, a state enterprise designed to forward collective visions of nature, technology, and nation through the implementation of large-scale infrastructure. Therefore, this dissertation brings together the historical study of modernity, business, and the relatively new field of “envirotech.” Bridging environmental history and the history of technology, “envirotech” sits at the nexus of nature, culture, technology, and power, allowing for a multivalent analysis of technological systems as mediators for human experiences with their environments. I push the boundaries of “envirotech” by interrogating the role of technology in changing perceptions of the environment; TCA’s public-facing articulations of the “modern envirotechnical nation” represented Canadian environments not just how they were, but how it ought to and appeared to be to the airline’s passengers
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