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The Global ETD Search service is a free service for researchers
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Showing 291 to 299 of 299 (0.061 seconds)Spelling suggestions: "subject:"allsensor Fusion"" "subject:"alfasensor Fusion""
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Enabling Autonomous Operation of Micro Aerial Vehicles Through GPS to GPS-Denied TransitionsJackson, James Scott 11 November 2019 (has links)
Micro aerial vehicles and other autonomous systems have the potential to truly transform life as we know it, however much of the potential of autonomous systems remains unrealized because reliable navigation is still an unsolved problem with significant challenges. This dissertation presents solutions to many aspects of autonomous navigation. First, it presents ROSflight, a software and hardware architure that allows for rapid prototyping and experimentation of autonomy algorithms on MAVs with lightweight, efficient flight control. Next, this dissertation presents improvments to the state-of-the-art in optimal control of quadrotors by utilizing the error-state formulation frequently utilized in state estimation. It is shown that performing optimal control directly over the error-state results in a vastly more computationally efficient system than competing methods while also dealing with the non-vector rotation components of the state in a principled way. In addition, real-time robust flight planning is considered with a method to navigate cluttered, potentially unknown scenarios with real-time obstacle avoidance. Robust state estimation is a critical component to reliable operation, and this dissertation focuses on improving the robustness of visual-inertial state estimation in a filtering framework by extending the state-of-the-art to include better modeling and sensor fusion. Further, this dissertation takes concepts from the visual-inertial estimation community and applies it to tightly-coupled GNSS, visual-inertial state estimation. This method is shown to demonstrate significantly more reliable state estimation than visual-inertial or GNSS-inertial state estimation alone in a hardware experiment through a GNSS-GNSS denied transition flying under a building and back out into open sky. Finally, this dissertation explores a novel method to combine measurements from multiple agents into a coherent map. Traditional approaches to this problem attempt to solve for the position of multiple agents at specific times in their trajectories. This dissertation instead attempts to solve this problem in a relative context, resulting in a much more robust approach that is able to handle much greater intial error than traditional approaches.
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Faktorgraph-basierte Sensordatenfusion zur Anwendung auf einem QuadrocopterLange, Sven 12 December 2013 (has links)
Die Sensordatenfusion ist eine allgegenwärtige Aufgabe im Bereich der mobilen Robotik und darüber hinaus. In der vorliegenden Arbeit wird das typischerweise verwendete Verfahren zur Sensordatenfusion in der Robotik in Frage gestellt und anhand von neuartigen Algorithmen, basierend auf einem Faktorgraphen, gelöst sowie mit einer korrespondierenden Extended-Kalman-Filter-Implementierung verglichen. Im Mittelpunkt steht dabei das technische sowie algorithmische Sensorkonzept für die Navigation eines Flugroboters im Innenbereich. Ausführliche Experimente zeigen die Qualitätssteigerung unter Verwendung der neuen Variante der Sensordatenfusion, aber auch Einschränkungen und Beispiele mit nahezu identischen Ergebnissen beider Varianten der Sensordatenfusion. Neben Experimenten anhand einer hardwarenahen Simulation wird die Funktionsweise auch anhand von realen Hardwaredaten evaluiert.
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Digital Twin Development and Advanced Process Control for Continuous Pharmaceutical ManufacturingYan-Shu Huang (9175667) 25 July 2023 (has links)
<p>To apply Industry 4.0 technologies and accelerate the modernization of continuous pharmaceutical manufacturing, digital twin (DT) and advanced process control (APC) strategies are indispensable. The DT serves as a virtual representation that mirrors the behavior of the physical process system, enabling real-time monitoring and predictive capabilities. Consequently, this facilitates the feasibility of real-time release testing (RTRT) and enhances drug product development and manufacturing efficiency by reducing the need for extensive sampling and testing. Moreover, APC strategies are required to address variations in raw material properties and process uncertainties while ensuring that desired critical quality attributes (CQAs) of in-process materials and final products are maintained. When deviations from quality targets are detected, APC must provide optimal real-time corrective actions, offering better control performance than the traditional open loop-control method. The progress in DT and APC is beneficial in shifting from the paradigm of Quality-by-Test (QbT) to that of Quality-by-Design (QbD) and Quality-by-Control (QbC), which emphasize the importance of process knowledge and real-time information to ensure product quality.</p>
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<p>This study focuses on four key elements and their applications in a continuous dry granulation tableting process, including feeding, blending, roll compaction, ribbon milling and tableting unit operations. Firstly, the necessity of a digital infrastructure for data collection and integration is emphasized. An ISA-95-based hierarchical automation framework is implemented for continuous pharmaceutical manufacturing, with each level serving specific purposes related to production, sensing, process control, manufacturing operations, and business planning. Secondly, investigation of process analytical technology (PAT) tools for real-time measurements is highlighted as a prerequisite for effective real-time process management. For instance, the measurement of mass flow rate, a critical process parameter (CPP) in continuous manufacturing, was previously limited to loss-in-weight (LIW) feeders. To overcome this limitation, a novel capacitance-based mass flow sensor, the ECVT sensor, has been integrated into the continuous direct compaction process to capture real-time powder flow rates downstream of the LIW feeders. Additionally, the use of near-infrared (NIR)-based sensor for real-time measurement of ribbon solid fraction in dry granulation processes is explored. Proper spectra selection and pre-processing techniques are employed to transform the spectra into useful real-time information. Thirdly, the development of quantitative models that establish a link between CPPs and CQAs is addressed, enabling effective product design and process control. Mechanistic models and hybrid models are employed to describe the continuous direct compaction (DC) and dry granulation (DG) processes. Finally, applying APC strategies becomes feasible with the aid of real-time measurements and model predictions. Real-time optimization techniques are used to combine measurements and model predictions to infer unmeasured states or mitigate the impact of measurement noise. In this work, the moving horizon estimation-based nonlinear model predictive control (MHE-NMPC) framework is utilized. It leverages the capabilities of MHE for parameter updates and state estimation to enable adaptive models using data from the past time window. Simultaneously, NMPC ensures satisfactory setpoint tracking and disturbance rejection by minimizing the error between the model predictions and setpoint in the future time window. The MHE-NMPC framework has been implemented in the tableting process and demonstrated satisfactory control performance even when plant model mismatch exists. In addition, the application of MHE enables the sensor fusion framework, where at-line measurements and online measurements can be integrated if the past time window length is sufficient. The sensor fusion framework proves to be beneficial in extending the at-line measurement application from just validation to real-time decision-making.</p>
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Assessment of technologies and response strategies for lone agricultural worker incidentsAaron Etienne (6570041) 08 March 2024 (has links)
<p dir="ltr"><a href="" target="_blank">ABSTRACT</a></p><p dir="ltr">A literature review was conducted, to determine and gain a better understanding of the environmental, technological, physiological, and psychological issues that lone agricultural workers potentially face in the event they are involved in an emergency. An investigation was conducted of communication devices used in other industries where working alone was common, to monitor for and detect incident occurrences. An assessment of currently available emergency alert software and sensing technology for <a href="" target="_blank">communication </a><a href="#_msocom_1" target="_blank">[AE1]</a> devices was also undertaken in this review.</p><p dir="ltr">Three hundred and sixty-eight U.S. cases of fatalities or injuries were analyzed in which working alone was identified as a contributing factor. Cases included lone agricultural workers, between the ages 15-64, who were identified from a convenient sample of incident reports from <a href="" target="_blank">2016-2021</a><a href="#_msocom_2" target="_blank">[AE2]</a> . Of the 368 lone agricultural worker incidents analyzed, 38% (140) were caused by tractor rollover or tractor runover, and ATV/ UTV rollovers. Grain bin entrapments accounted for 13% (48) of all identified cases, of which 86% (42) were fatal. Thirty-three percent (121) of the identified incidents involved equipment roll over (not including runovers), and 50% of identified victims, when age was known, were 57 years of age or older. In 11 cases (3%), the victim was under 15 years old and active in agricultural-related tasks at the time of incident occurrence.</p><p dir="ltr">Geospatial Information Systems (GIS) tools were used to identify the proximity of Emergency Medical Service (EMS) facilities and cellular towers from a convenient sample of 29 fatal and serious agricultural related injuries from 2016-2021, occurring in the state of Indiana. This analysis found that there were substantially fewer EMS facilities within close proximity to documented rural incident locations compared to injuries or fatalities occurring closer to a populated area. There were also fewer cellular towers within close proximity of incidents located primarily on or near rural agricultural land. More densely populated areas tended to have a greater density of EMS and cellular tower locations, with, most likely, more favorable outcomes from injuries due to shorter <a href="" target="_blank">response times.</a><a href="#_msocom_3" target="_blank">[AE3]</a></p><p dir="ltr">An investigation of the physical and operational impact that agricultural equipment would have on the efficacy of commercially available wearable technologies was undertaken, to detect the potential injury-causing agricultural incident. Five experiments were conducted to test the feasibility of these selected wearable devices in detecting agricultural-related incidents with the potential of causing serious injuries. Only one <a href="" target="_blank">simulated agricultural incident</a> <a href="#_msocom_4" target="_blank">[AE4]</a> successfully triggered incident detection. <a href="" target="_blank">Incidents successfully triggered incident detection on one wearable device, the Garmin Vivoactive 4 smartwatch. </a><a href="#_msocom_5" target="_blank">[AE5]</a></p><p dir="ltr">Recommendations included greater emphasis on the hazards associated with lone workers assigned agricultural workplaces, development of new, evidence-based educational resources to incorporate in current prevention strategies directed at farmers, ranchers, and agricultural workers, enhanced supervision of young agricultural workers and compliance with existing child labor regulations, equipping lone workers with appropriate cellphones and/ or wearable technologies to be carried in their vehicles, agricultural equipment, or on their person, use of electronic surveillance or monitoring equipment, written policies and procedures that enhance awareness of worker locations and conditions on a regular basis, and adherence to existing federal and state workplace safety and health regulations related to lone workers.</p><p><br></p><p dir="ltr"><a href="#_msoanchor_1" target="_blank">[AE1]</a>Changed</p><p dir="ltr"><a href="#_msoanchor_2" target="_blank">[AE2]</a>Fixed</p><p dir="ltr"><a href="#_msoanchor_3" target="_blank">[AE3]</a>I’m not sure how to address that more rural people are dying, given the limited scope and criteria for selection of the incidents selected in this study.</p><p dir="ltr"><a href="#_msoanchor_4" target="_blank">[AE4]</a>Not sure if this Is the best way to say it. I may end up cutting this part. I’ll pair the abstract down to ~250 words. For whatever reason, I thought the intro chapter abstract needed to be longer for a dissertation.</p><p dir="ltr"><a href="#_msoanchor_5" target="_blank">[AE5]</a>Shortened this paragraph and removed unnecessary detail, for clarity.</p>
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Towards Inertial Sensor-Based Position Estimation in BoulderingKoller, Tom, Laue, Tim, Frese, Udo 14 October 2022 (has links)
For some years, inertial sensors have become increasingly popular in various sports applications due to their small size and weight. However – due to the problem of sensor drift – additional sensors are usually required to obtain reliable position estimates. In this paper, we present an approach for position estimation in bouldering that relies solely on inertial sensors and domain knowledge that is modeled as a virtual sensor. / Seit einigen Jahren erfreuen sich Inertialsensoren aufgrund ihrer geringen Größe und ihres geringen Gewichts zunehmender Beliebtheit in verschiedenen Sportanwendungen. Aufgrund des Problems des Sensordrifts sind jedoch in der Regel zusätzliche Sensoren erforderlich, um zuverlässige Positionsschätzungen zu erhalten. In diesem Beitrag stellen wir einen Ansatz zur Positionsschätzung beim Bouldern vor, der sich ausschließlich auf Inertialsensoren und Domänenwissen stützt, welches als virtueller Sensor modelliert wird.
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Platform development of body area network for gait symmetry analysis using IMU and UWB technologyPersson, Anders January 2018 (has links)
Having a device with the capability of measure motions from gait produced by a human being, could be of most importance in medicine and sports. Physicians or researchers could measure and analyse key features of a person's gait for the purpose of rehabilitation or science, regarding neurological disabilities. Also in sports, professionals and hobbyists could use such a device for improving their technique or prevent injuries when performing. In this master thesis, I present the research of what technology is capable of today, regarding gait analysis devices. The research that was done has then help the development of a suggested standalone hardware sensor node for a Body Area Network, that can support research in gait analysis. Furthermore, several algorithms like for instance UWB Real-Time Location and Dead Reckoning IMU/AHRS algorithms, have been implemented and tested for the purpose of measuring motions and be able to run on the sensor node device. The work in this thesis shows that a IMU sensor have great potentials for generating high rate motion data while performing on a small mobile device. The UWB technology on the other hand, indicates a disappointment in performance regarding the intended application but can still be useful for wireless communication between sensor nodes. The report also points out the importance of using a high performance micro controller for achieving high accuracy in measurements.
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Sensores virtuales para procesos con medidas escasas y retardos temporalesPeñarrocha Alós, Ignacio 22 December 2008 (has links)
En este trabajo se aborda el problema de controlar un proceso cuya salida se muestrea de forma irregular. Para ello se propone utilizar un predictor que estima las salidas del proceso en instantes regulares de tiempo más un
controlador convencional que calcula la acción de control a partir de las estimaciones del predictor (técnica conocida como control inferencial).
La predicción consiste en estimar las variables de salida que se desean controlar a partir de las mediciones realizadas con diversos sensores utilizando para ello un modelo matemático del proceso. El filtro de Kalman permite hacer la predicción de forma óptima si las perturbaciones tienen una distribución gaussiana de media cero, pero con el inconveniente de requerir un elevado coste computacional cuando se utilizan diferentes sensores con retardos temporales variantes. En este trabajo se propone una estrategia de predicción alternativa
de bajo coste computacional cuyo diseño se basa en el conocimiento de la disponibilidad de mediciones y de los retardos (del proceso, del sistema de medición o del sistema de transmisión de datos) y de la naturaleza de las
perturbaciones. Los predictores propuestos minimizan el error de predicción frente al muestreo aleatorio con retardos variantes, perturbaciones, ruido de medida, error de modelado, retardos en la acción de control e incertidumbre en los tiempos de medición. Las diferentes estrategias de diseño que se proponen se clasifican según el tipo de información que se dispone de las perturbaciones y del coste computacional requerido.
Se han planteado los diseños para sistemas monovariables, multivariables, lineales y no lineales. Asimismo, también se ha elaborado una forma más eficiente de incluir mediciones escasas con retardo en el filtro de Kalman, con el objetivo de reducir el coste computacional de la predicción.
En este trabajo se demuestra que los sistemas de control inferencial que utilizan los predictores propuestos cumplen con el principio de sep / Peñarrocha Alós, I. (2006). Sensores virtuales para procesos con medidas escasas y retardos temporales [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/3882
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Bayes Filters with Improved Measurements for Visual Object Tracking / Bayes Filter mit verbesserter Messung für das Tracken visueller ObjekteLiu, Guoliang 20 March 2012 (has links)
No description available.
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Evaluation of Target Tracking Using Multiple Sensors and Non-Causal AlgorithmsVestin, Albin, Strandberg, Gustav January 2019 (has links)
Today, the main research field for the automotive industry is to find solutions for active safety. In order to perceive the surrounding environment, tracking nearby traffic objects plays an important role. Validation of the tracking performance is often done in staged traffic scenarios, where additional sensors, mounted on the vehicles, are used to obtain their true positions and velocities. The difficulty of evaluating the tracking performance complicates its development. An alternative approach studied in this thesis, is to record sequences and use non-causal algorithms, such as smoothing, instead of filtering to estimate the true target states. With this method, validation data for online, causal, target tracking algorithms can be obtained for all traffic scenarios without the need of extra sensors. We investigate how non-causal algorithms affects the target tracking performance using multiple sensors and dynamic models of different complexity. This is done to evaluate real-time methods against estimates obtained from non-causal filtering. Two different measurement units, a monocular camera and a LIDAR sensor, and two dynamic models are evaluated and compared using both causal and non-causal methods. The system is tested in two single object scenarios where ground truth is available and in three multi object scenarios without ground truth. Results from the two single object scenarios shows that tracking using only a monocular camera performs poorly since it is unable to measure the distance to objects. Here, a complementary LIDAR sensor improves the tracking performance significantly. The dynamic models are shown to have a small impact on the tracking performance, while the non-causal application gives a distinct improvement when tracking objects at large distances. Since the sequence can be reversed, the non-causal estimates are propagated from more certain states when the target is closer to the ego vehicle. For multiple object tracking, we find that correct associations between measurements and tracks are crucial for improving the tracking performance with non-causal algorithms.
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