REAL-TIME ERROR DETECTION AND CORRECTION FOR ROBUST OPERATION OF AUTONOMOUS SYSTEMS USING ENCODED STATE CHECKS

The objective of the proposed research is to develop methodologies, support algorithms and software-hardware infrastructure for detection, diagnosis, and correction of failures for actuators, sensors and control software in linear and nonlinear state variable systems with the help of multiple checks employed in the system. This objective is motivated by the proliferation of autonomous sense-and-control real-time systems, such as intelligent robots and self-driven cars which must maintain a minimum level of performance in the presence of electro-mechanical degradation of system-level components in the field as well as external attacks in the form of transient errors. A key focus is on rapid recovery from the effects of such anomalies and impairments with minimal impact on system performance while maintaining low implementation overhead as opposed to traditional schemes for recovery that rely on duplication or triplication. On-line detection, diagnosis and correction techniques are investigated and rely on analysis of system under test response signatures to real-time stimulus. For on-line error detection and diagnosis, linear and nonlinear state space encodings of the system under test are used and specific properties of the codes, as well as machine learning model based approaches were used are analyzed in real-time. Recovery is initiated by copying check model values to correct error for sensor and control software malfunction, and by redesigning the controller parameter on-the-fly for actuators to restore system performance. Future challenges that need to be addressed include viability studies of the proposed techniques on mobile autonomous system in distributed setting as well as application to systems with soft as well as hard real-time performance constraints.Ph.D

Fault Estimation Schemes of Wireless Networked Control Systems for Real-Time Industrial Applications

Bedingt durch das rasante Wachstum der Mikroelektronik sowie der Informations- und Kommunikationstechnologien wurde viel Aufmerksamkeit der Erforschung von drahtlos vernetzten Regelsystemen (W-NCS) gewidmet. Die Entwicklung der W-NCS schuf neue Herausforderungen für die Technologien zur Fehlerabschätzung (FE) bezüglich Störungen bei der Datenübertragung, wie zum Beispiel Übertragungsverzögerung, Paketverlust und Jitter. Um die Sicherheit und Zuverlässigkeit des Systems zu gewährleisten, ist die Entwicklung eines effektiven FE Ansatzes in vernetzten Systemen von zentraler Bedeutung. Andererseits sollten mit der Ausrichtung auf Anwendungen in der Echtzeit-Industrieautomatisierung die spezifischen Eigenschaften der Netzwerke angemessen berücksichtigt werden. Da die Aufgabe der Übertragung von Messungen und Steuerbefehlen in der Regel über einen Zeitraum deterministisch ist, sollten ein deterministischer Übertragungsmechanismus und die entsprechenden FE Verfahren vorgeschlagen werden. Motiviert durch die weit verbreitete Verwendung von sowohl zentralen und als auch dezentralen Strukturen in industriellen Prozesse, ist die Entwicklung sowohl von zentralen und als auch von dezentralen FE Methoden für W-NCS in der Industrieautomation das primäre Ziel dieser Arbeit. Diese Arbeit widmet sich zuerst der Modellierung der Prozesse und der Kommunikationsstruktur. Für die Modellierung der Kommunikation wird das Medium Access Control (MAC) Protokoll basierend auf dem Mehrfachzugriff im Zeitmultiplex (TDMA) modifiziert, um die Echtzeitfähigkeit zu gewährleisten. Das Prozessmodell wird unter Berücksichtigung der Abtastraten auf Basis der hierarchischen Struktur des W-NCS aufgestellt. Durch die Berücksichtigung der Unsicherheit von Netzwerken und Auswirkungen von Fehlern wird ein linear periodisches (LP) Systemmodell, durch die Integration des Kommunikationsmodells und des Prozessmodells, als Basis für die spätere Entwicklung präsentiert. Die weiteren Untersuchungen konzentrieren sich auf die Entwicklung von FE Modellen für zentrale und dezentrale W-NCS. Um eine erhöhte Robustheit gegen unbekannte Störungen und den Schätzfehler des Anfangszustandes zu erreichen, wird ein zentraler FE Ansatz mit Hilfe des stochastischen Modells im Krein Raum vorgeschlagen. Für die dezentrale FE wird der Algorithmus für jedes Teilsystem implementiert und die Kopplungsbeziehungen zwischen den Teilsystemen entsprechend berücksichtigt. Basierend darauf werden die FE Ansätze mit zwei Arten von Residuensignalen präsentiert, nicht-verteilten Residuen und verteilten Residuen,. Um die Wirksamkeit der entwickelten FE Ansätze darzustellen, wird in dieser Arbeit die Industrieplattform WiNC, zumammen mit einem Dreitanksystem verwendet. Die FE Algorithmen wurden in den drei Datenübertragungsfällen Fehlerfrei, mit Verzögerungen und mit Paketverlust verifiziert, so dass die Robustheit gegenüber einer unvollkommenen Kommunikation demonstriert wird. Darüber hinaus wurde die Leistungsfähigkeit bezüglich Sensor- und Aktuator-FE ausgiebig auf der WiNC Plattform getestet.With the rapid growth of microelectronics, information and communication technologies, much attention has been paid on the research of wireless networked control systems (W-NCSs). The development of W-NCSs raises new challenges in fault estimation (FE) technology regarding to the imperfect data transmission, such as transmission delay, packet loss, jitter and so on. To ensure the system safety and reliability, an effective FE approach over networks is of prime importance to be developed. On the other hand, aiming for the applications on real-time industrial automation, the specific characteristics of network should be properly considered. Since the transmission tasks of measurements and control commands are normally deterministic over a period of time, a deterministic transmission mechanism and the relevant FE scheme should be proposed. Motivated by the widespread popularity of centralized and decentralized structures for industrial processes, development of both centralized and decentralized FE schemes for W-NCSs, which can be applied on industrial automation, is the primary objective of this thesis. This thesis is first dedicated to the modeling of communication and process. For the communication modeling, time division multiple access (TDMA) based medium access control (MAC) protocol is modified to guarantee the real-time performance. The process model is built considering multirate sampling based on the hierarchical structure of W-NCSs. By observing the uncertainty of networks and effects of faults, a linear periodic (LP) system model, which is the integration of communication model and process model, is presented as a basis for the later developments. The further study focuses on the development of FE schemes for both centralized and decentralized W-NCSs. To reach an enhanced robustness against unknown disturbance and initial state estimate error, the centralized FE approach is proposed with the help of stochastic model in Krein space. For decentralized FE, the algorithm is implemented by every sub-system, and the coupling relations between sub-systems should be properly considered. Based on it, the FE approaches are presented with two kinds of residual signals, i.e., non-shared residuals and shared residuals, respectively. To illustrate the effectiveness of the derived FE approaches, an industrial platform WiNC integrated with three-tank system is utilized in this thesis. The FE algorithms have been verified for three data transmission cases, i.e., sampling-based, delay and packet loss, so that the robustness against imperfect communication is demonstrated. Moreover, the performances of sensor and actuator FE have also been tested well on WiNC platform

Technology 2003: The Fourth National Technology Transfer Conference and Exposition, volume 2

Proceedings from symposia of the Technology 2003 Conference and Exposition, Dec. 7-9, 1993, Anaheim, CA, are presented. Volume 2 features papers on artificial intelligence, CAD&E, computer hardware, computer software, information management, photonics, robotics, test and measurement, video and imaging, and virtual reality/simulation

Satellite Communications

This study is motivated by the need to give the reader a broad view of the developments, key concepts, and technologies related to information society evolution, with a focus on the wireless communications and geoinformation technologies and their role in the environment. Giving perspective, it aims at assisting people active in the industry, the public sector, and Earth science fields as well, by providing a base for their continued work and thinking

Applications

Volume 3 describes how resource-aware machine learning methods and techniques are used to successfully solve real-world problems. The book provides numerous specific application examples: in health and medicine for risk modelling, diagnosis, and treatment selection for diseases in electronics, steel production and milling for quality control during manufacturing processes in traffic, logistics for smart cities and for mobile communications

Applications

Volume 3 describes how resource-aware machine learning methods and techniques are used to successfully solve real-world problems. The book provides numerous specific application examples: in health and medicine for risk modelling, diagnosis, and treatment selection for diseases in electronics, steel production and milling for quality control during manufacturing processes in traffic, logistics for smart cities and for mobile communications

Recent Advances in Wireless Communications and Networks

This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters

Middle Atmosphere Program. Handbook for MAP, volume 20

Various topics related to investigations of the middle atmosphere are discussed. Numerical weather prediction, performance characteristics of weather profiling radars, determination of gravity wave and turbulence parameters, case studies of gravity-wave propagation, turbulence and diffusion due to gravity waves, the climatology of gravity waves, mesosphere-stratosphere-troposphere radar, antenna arrays, and data management techniques are among the topics discussed

Research on Teaching and Learning In Biology, Chemistry and Physics In ESERA 2013 Conference

This paper provides an overview of the topics in educational research that were published in the ESERA 2013 conference proceedings. The aim of the research was to identify what aspects of the teacher-student-content interaction were investigated frequently and what have been studied rarely. We used the categorization system developed by Kinnunen, Lampiselkä, Malmi and Meisalo (2016) and altogether 184 articles were analyzed. The analysis focused on secondary and tertiary level biology, chemistry, physics, and science education. The results showed that most of the studies focus on either the teacher’s pedagogical actions or on the student - content relationship. All other aspects were studied considerably less. For example, the teachers’ thoughts about the students’ perceptions and attitudes towards the goals and the content, and the teachers’ conceptions of the students’ actions towards achieving the goals were studied only rarely. Discussion about the scope and the coverage of the research in science education in Europe is needed.Peer reviewe