Learning and Reacting with Inaccurate Prediction: Applications to Autonomous Excavation

Motivated by autonomous excavation, this work investigates solutions to a class of problem where disturbance prediction is critical to overcoming poor performance of a feedback controller, but where the disturbance prediction is intrinsically inaccurate. Poor feedback controller performance is related to a fundamental control problem: there is only a limited amount of disturbance rejection that feedback compensation can provide. It is known, however, that predictive action can improve the disturbance rejection of a control system beyond the limitations of feedback. While prediction is desirable, the problem in excavation is that disturbance predictions are prone to error due to the variability and complexity of soil-tool interaction forces. This work proposes the use of iterative learning control to map the repetitive components of excavation forces into feedforward commands. Although feedforward action shows useful to improve excavation performance, the non-repetitive nature of soil-tool interaction forces is a source of inaccurate predictions. To explicitly address the use of imperfect predictive compensation, a disturbance observer is used to estimate the prediction error. To quantify inaccuracy in prediction, a feedforward model of excavation disturbances is interpreted as a communication channel that transmits corrupted disturbance previews, for which metrics based on the sensitivity function exist. During field trials the proposed method demonstrated the ability to iteratively achieve a desired dig geometry, independent of the initial feasibility of the excavation passes in relation to actuator saturation. Predictive commands adapted to different soil conditions and passes were repeated autonomously until a pre-specified finish quality of the trench was achieved. Evidence of improvement in disturbance rejection is presented as a comparison of sensitivity functions of systems with and without the use of predictive disturbance compensation

Small business innovation research. Abstracts of completed 1987 phase 1 projects

Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered

Academic plagiarism : understanding it to take responsible action

With the proliferation of the Internet, overcoming plagiarism seems insurmountable for students, teachers and researchers, who tend to find little choice between academia and the law in this regard. With a multidisciplinary approach and twenty years of expertise and research on this topic, Prof. Bergadaà proposes a concrete methodology for addressing this issue, both for the plagiarised and plagiariser, as well as for the institutions and associations. Researchers, students, directors of journals and institutions, as well as other actors in the scientific arena such as policy makers and lawyers are all concerned with preserving the value of integrity at the core of research ethics

NASA Tech Briefs Index, 1977, volume 2, numbers 1-4

Announcements of new technology derived from the research and development activities of NASA are presented. Abstracts, and indexes for subject, personal author, originating center, and Tech Brief number are presented for 1977

Continuous Autonomous UAV Inspection for FPSO vessels

This Master's thesis represents the preliminary design study and proposes the unmanned aerial vehicle (UAV) -based inspection framework, comprising several multirotors with automatic charging and deployment for 24/7 integrity inspection tasks. This project has three main topics. First one describes the operational environment and existing regulations that cover use of UAVs. It forms the basis for proposal of the relevant use-case scenarios. Third part comprises two chapters, where design of concept and framework is being based on the previous factors. It shows that before implementation of fully autonomous inspection system, there is a need to cover both regulatory and technical gaps. It can be explained by the fact that there does not exist any autonomous inspection system today. Thus, this project can be seen as a base for future development of the UAV-based inspection system, as it focuses on creation of a general framework

The Real Winner of the Second World War: Patriotic Consumption and the Formation of a Society of Spin

The unique circumstances in the United States during the Second World War allowed for business to continue as usual on the home front. Advertisers, public relations experts, and big business all worked for the government to promote the war effort. For a period of time major companies in the United States were producing advertisements that persuaded citizens to support rationing, buy war bonds, hate the enemy, and keep their brand names in mind in the post-war years. Companies who supported the war effort had their brands connected with ideas of patriotism and enjoyed the success of brand loyal consumers in the economic post-war boom. The advertisers and public relations experts cemented a place for their professions in the United States by showing their effectiveness to sway the minds of the public to support the war effort. The advertisements produced during the Second World War acted as a form of wartime propaganda that convinced that sold nationalistic ideology and demonization of the enemy alongside a service of product. The advertising campaigns of the Second World War show a period of time where government, public relations, advertising, and business developed a relationship that changed the way Americans viewed consumerism. It is my assertion that by analyzing the advertising campaigns from the Second World War it is possible to trace the rise of consumer culture dominance, the solidification of the fields of public relations and advertising, and the connection between purchasing brand products and patriotism

NASA Tech Briefs, August 1991

Topics: New Product Ideas; NASA TU Services; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

The Trail, 1970-04-10

https://soundideas.pugetsound.edu/thetrail_all/2015/thumbnail.jp

NASA SBIR abstracts of 1991 phase 1 projects

The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included