Modeling Operator Behavior in the Safety Analysis of Collaborative Robotic Applications

Human-Robot Collaboration is increasingly prominent in peo- ple's lives and in the industrial domain, for example in manufacturing applications. The close proximity and frequent physical contacts between humans and robots in such applications make guaranteeing suitable levels of safety for human operators of the utmost importance. Formal veri- cation techniques can help in this regard through the exhaustive explo- ration of system models, which can identify unwanted situations early in the development process. This work extends our SAFER-HRC method- ology with a rich non-deterministic formal model of operator behaviors, which captures the hazardous situations resulting from human errors. The model allows safety engineers to rene their designs until all plausi- ble erroneous behaviors are considered and mitigated

Model-based operator guidance in interactive, semi-automated production processes

This contribution focuses on the task of guiding and supervision of technical processes realized by human operators. The review of publications of the last decades discloses that especially technical processes with strong interconnection of human operator and manufacturing process are not adequately addressed by the evolved automation approaches. Integrating human process knowledge and experience into the resulting automation system is still a major concern. Besides the introduction of automation in a handcrafting process that is increasing the overall system complexity, the design of the human-machine interface to the automation system is of central importance. Within this thesis, the trade-off between manual manufacturing and automation is addressed by a semi-automation approach. The application example is the no-bake molding process, a mold manufacturing process for casts that is traditionally handmade. Within this process the human operator plays a central role (i.e. knowledge and expertise), whereas the (intelligent) automation is carrying out physical operation, which is guided and supervised by the human operator. This is achieved by experimentally identified quality representing process variables that allow for in-process feedback to the human operator. Process guiding assistance is given using a formalization approach of the human-automation-interaction. By deducing situative information of interest from the resulting human-automation-system model with respect to the current process goal, the established process model is used for supervision and assistance of the overall process. The design of the human-machine-interface is based on a detailed analysis of the handcrafted process and is realized as a direct, intuitively usable, marker-based interaction technique. The integrated human-automation-system and the corresponding human-machine-interface with process guidance assistance functionality is initially evaluated. The results are discussed for the future work with respect to the individual, human operator-specific process understanding and process reproducibility.Diese Arbeit befasst sich mit Fachkraftaufgaben in der Führung und Überwachung von technischen Prozessen. Die Übersicht der Publikationen der letzten Jahrzehnte eröffnet, dass insbesondere technische Prozesse mit enger Verknüpfung von Mensch und Herstellungsprozess bei den entwickelten Automatisierungsansätzen nicht hinreichend berücksichtigt werden. Die Integration von Prozesswissen und -erfahrung in das resultierende Automatisierungssystem bleibt eine offene Fragestellung. Neben der Einführung von Automation in Handarbeitsprozesse, die die Komplexität des Gesamtsystems erhöhen, ist die Gestaltung der Mensch-Maschine-Schnittstelle zum Automatisierungssystem von zentraler Bedeutung. Der Konflikt zwischen Handarbeit und Automatisierung wird in dieser Arbeit durch die Einführung einer Teilautomatisierung gelöst. Das Anwendungsbeispiel ist das Kaltharzverfahren, ein traditionell in Handarbeit bewältigter Herstellungsprozess für Gussformen. In diesem Prozess spielt die Fachkraft eine zentrale Rolle (z. B. durch ihr Prozesswissen und ihre Expertise), während die (intelligente) Automatisierung –geführt und überwacht durch die Fachkraft– anfallende physische Aktionen ausführt. Dies wird durch experimentell ermit- telte qualitäts-beschreibende Prozessgrößen erreicht, die eine in-prozess Rückführung zum Bedienpersonal ermöglichen. Prozessführungsassistenz ist basierend auf die Formalisierung der Mensch-Automation-Interaktion gegeben. Durch die Bestimmung von situativen Informationen hoher Wichtigkeit aus dem resultierenden Mensch-Automation-System Modell bezogen auf das aktuelle Prozessziel, wird das bestehende Prozessmodell zur Überwachung und Prozessführungsassistenz des Gesamtprozesses genutzt. Die Gestaltung der Mensch-Maschine-Schnittstelle basiert auf einer detaillierten Analyse des Handarbeitsprozesses und ist als direkte, intuitiv bedienbare, markerbasierte Interaktionstechnik realisiert. Das integrierte Mensch-Automation-System sowie die zugehörige Mensch-Maschine-Schnittstelle inklusive Prozessführungsassistenzfunktionen wurden initial evaluiert. Die erzielten Ergebnisse werden hinsichtlich des individuellen, fachkraftabhängigen Prozesswissens und der Reproduzierbarkeit für den Ausblick diskutiert

Structural usability techniques for dependable HCI.

Since their invention in the middle of the twentieth century, interactive computerised systems have become more and more common to the point of ubiquity. While formal techniques have developed as tools for understanding and proving things about the behaviour of computerised systems, those that involve interaction with human users present some particular challenges which are less well addressed by traditional formal methods. There is an under-explored space where interaction and the high assurances provided by formal approaches meet. This thesis presents two techniques which fit into this space, and which can be used to automatically build and analyse formal models of the interaction behaviour of existing systems. Model discovery is a technique for building a state space-based formal model of the interaction behaviour of a running system. The approach systematically and exhaustively simulates the actions of a user of the system; this is a dynamic analysis technique which requires tight integration with the running system and (in practice) its codebase but which, when set up, can proceed entirely automatically. Theorem discovery is a technique for analysing a state space-based formal model of the interaction behaviour of a system, looking for strings of user actions that have equivalent effects across all states of the system. The approach systematically computes and compares the effects of ever-longer strings of actions, though insights can also arise from strings that are almost equivalent, and also from considering the meaning of sets of such equivalences. The thesis introduces and exemplifies each technique, considers how they may be used together, and demonstrates their utility and novelty, with case studies

From a formal user model to design rules

Design rules sometimes seem to contradict. We examine how a formal description of user behaviour can help explain the context when such rules are, or are not, applicable. We describe how they can be justified from a formally specified generic user model. This model was developed by formalising cognitively plausible behaviour, based on results from cognitive psychology. We examine how various classes of erroneous actions emerge from the underlying model. Our lightweight semi-formal reasoning from the user model makes predictions that could be used as the basis for further usability studies. Although the user model is very simple, a range of error patterns and design principles emerge