2,153 research outputs found

    Evaluating the Effect of Integrated System Health Management on Mission Effectiveness

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    This research used systems architecture to develop a model that determined the effect of Integrated System Health Management (ISHM) on mission success rates for unmanned aerial systems (UAS). To evaluate this effect, a simulation model was developed and used to analyze the difference between mission success rates for a theoretical UAS with and without ISHM. Design of Experiments analysis techniques were used to map a response surface that modeled the difference between mission success rates calculated for current health management technology and ISHM. Using representative data for a UAS, the analysis determined that the failure distribution parameters, sensor quality (which determines the relationship between probability of detection and probability of false alarm), and probability of an imminent fault during a mission were significant to the model. The result of the model determined that ISHM can result in a significant improvement on mission assurance, especially when implemented with higher quality sensors and on vehicles where the probability of imminent failure is higher relative to the mission times and time between preventative maintenance. This appears consistent with the premise that ISHM can support an extension of preventative maintenance intervals with an attendant reduction in sustainment cost

    Advanced avionics concepts: Autonomous spacecraft control

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    A large increase in space operations activities is expected because of Space Station Freedom (SSF) and long range Lunar base missions and Mars exploration. Space operations will also increase as a result of space commercialization (especially the increase in satellite networks). It is anticipated that the level of satellite servicing operations will grow tenfold from the current level within the next 20 years. This growth can be sustained only if the cost effectiveness of space operations is improved. Cost effectiveness is operational efficiency with proper effectiveness. A concept is presented of advanced avionics, autonomous spacecraft control, that will enable the desired growth, as well as maintain the cost effectiveness (operational efficiency) in satellite servicing operations. The concept of advanced avionics that allows autonomous spacecraft control is described along with a brief description of each component. Some of the benefits of autonomous operations are also described. A technology utilization breakdown is provided in terms of applications

    Cooperative Virtual Sensor for Fault Detection and Identification in Multi-UAV Applications

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    This paper considers the problem of fault detection and identification (FDI) in applications carried out by a group of unmanned aerial vehicles (UAVs) with visual cameras. In many cases, the UAVs have cameras mounted onboard for other applications, and these cameras can be used as bearing-only sensors to estimate the relative orientation of another UAV. The idea is to exploit the redundant information provided by these sensors onboard each of the UAVs to increase safety and reliability, detecting faults on UAV internal sensors that cannot be detected by the UAVs themselves. Fault detection is based on the generation of residuals which compare the expected position of a UAV, considered as target, with the measurements taken by one or more UAVs acting as observers that are tracking the target UAV with their cameras. Depending on the available number of observers and the way they are used, a set of strategies and policies for fault detection are defined. When the target UAV is being visually tracked by two or more observers, it is possible to obtain an estimation of its 3D position that could replace damaged sensors. Accuracy and reliability of this vision-based cooperative virtual sensor (CVS) have been evaluated experimentally in a multivehicle indoor testbed with quadrotors, injecting faults on data to validate the proposed fault detection methods.Comisión Europea H2020 644271Comisión Europea FP7 288082Ministerio de Economia, Industria y Competitividad DPI2015-71524-RMinisterio de Economia, Industria y Competitividad DPI2014-5983-C2-1-RMinisterio de Educación, Cultura y Deporte FP

    Fault Diagnosis and Fault Handling for Autonomous Aircraft

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    Cooperative Sensor Fault Recovery in Multi-UAV Systems

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    IEEE International Conference on Robotics and Automation (ICRA), 16-21 May 2016 Stockholm, SwedenThis paper presents the design and experimental validation of a Fault Detection, Identification and Recovery (FDIR) system intended for multi-UAV applications. The system exploits the information provided by internal position, attitude and visual sensors onboard the UAVs of the fleet for detecting faults in the measurements of the position and attitude sensors of any of the member vehicles. Considering the observations provided by two or more UAVs in a cooperative way, it is possible to identify the source of the fault, but also implement a Cooperative Virtual Sensor (CVS) which provides a redundant position and velocity estimation of the faulty UAV that can be used for replacing its internal sensor. The vision-based FDIR system has been validated experimentally with quadrotors in an indoor testbed. In particular, fault detection and identification has been evaluated injecting a fault pattern offline on the position measurements, while the CVS has been applied in real time for the recovery phase.Ministerio de Educación Cultura y Deporte ICT-2011-28808

    Autonomous Systems, Robotics, and Computing Systems Capability Roadmap: NRC Dialogue

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    Contents include the following: Introduction. Process, Mission Drivers, Deliverables, and Interfaces. Autonomy. Crew-Centered and Remote Operations. Integrated Systems Health Management. Autonomous Vehicle Control. Autonomous Process Control. Robotics. Robotics for Solar System Exploration. Robotics for Lunar and Planetary Habitation. Robotics for In-Space Operations. Computing Systems. Conclusion

    Space shuttle low cost/risk avionics study

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    All work breakdown structure elements containing any avionics related effort were examined for pricing the life cycle costs. The analytical, testing, and integration efforts are included for the basic onboard avionics and electrical power systems. The design and procurement of special test equipment and maintenance and repair equipment are considered. Program management associated with these efforts is described. Flight test spares and labor and materials associated with the operations and maintenance of the avionics systems throughout the horizontal flight test are examined. It was determined that cost savings can be achieved by using existing hardware, maximizing orbiter-booster commonality, specifying new equipments to MIL quality standards, basing redundancy on cost effective analysis, minimizing software complexity and reducing cross strapping and computer-managed functions, utilizing compilers and floating point computers, and evolving the design as dictated by the horizontal flight test schedules

    An energy-aware architecture : a practical implementation for autonomous underwater vehicles

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    Energy awareness, fault tolerance and performance estimation are important aspects for extending the autonomy levels of today’s autonomous vehicles. Those are related to the concepts of survivability and reliability, two important factors that often limit the trust of end users in conducting large-scale deployments of such vehicles. With the aim of preparing the way for persistent autonomous operations this work focuses its efforts on investigating those effects on underwater vehicles capable of long-term missions. A novel energy-aware architecture for autonomous underwater vehicles (AUVs) is presented. This, by monitoring at runtime the vehicle’s energy usage, is capable of detecting and mitigating failures in the propulsion subsystem, one of the most common sources of mission-time problems. Furthermore it estimates the vehicle’s performance when operating in unknown environments and in the presence of external disturbances. These capabilities are a great contribution for reducing the operational uncertainty that most underwater platforms face during their deployment. Using knowledge collected while conducting real missions the proposed architecture allows the optimisation of on-board resource usage. This improves the vehicle’s effectiveness when operating in unknown stochastic scenarios or when facing the problem of resource scarcity. The architecture has been implemented on a real vehicle, Nessie AUV, used for real sea experiments as part of multiple research projects. These gave the opportunity of evaluating the improvements of the proposed system when considering more complex autonomous tasks. Together with Nessie AUV, the commercial platform IVER3 AUV has been involved in the evaluating the feasibility of this approach. Results and operational experience, gathered both in real sea scenarios and in controlled environment experiments, are discussed in detail showing the benefits and the operational constraints of the introduced architecture, alongside suggestions for future research directions

    Mechatronic Systems

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    Mechatronics, the synergistic blend of mechanics, electronics, and computer science, has evolved over the past twenty five years, leading to a novel stage of engineering design. By integrating the best design practices with the most advanced technologies, mechatronics aims at realizing high-quality products, guaranteeing at the same time a substantial reduction of time and costs of manufacturing. Mechatronic systems are manifold and range from machine components, motion generators, and power producing machines to more complex devices, such as robotic systems and transportation vehicles. With its twenty chapters, which collect contributions from many researchers worldwide, this book provides an excellent survey of recent work in the field of mechatronics with applications in various fields, like robotics, medical and assistive technology, human-machine interaction, unmanned vehicles, manufacturing, and education. We would like to thank all the authors who have invested a great deal of time to write such interesting chapters, which we are sure will be valuable to the readers. Chapters 1 to 6 deal with applications of mechatronics for the development of robotic systems. Medical and assistive technologies and human-machine interaction systems are the topic of chapters 7 to 13.Chapters 14 and 15 concern mechatronic systems for autonomous vehicles. Chapters 16-19 deal with mechatronics in manufacturing contexts. Chapter 20 concludes the book, describing a method for the installation of mechatronics education in schools
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