Industrial human-robot collaboration: maximizing performance while maintaining safety

The goal of this thesis is to maximize performance in collaborative applications, while maintaining safety. For this, assembly workplaces are analyzed, typical tasks identified, and the potential of collaborative robots is elaborated. Current safety regulations are analyzed in order to identify the challenges in safe human-robot collaboration. Different methods are proposed to solve inefficiency in collaborative applications, in particular, intuitive programming of collaborative robots, efficient control with human-in-the-loop constraints, and a hardware solution, the Robotic Airbag.Das Ziel dieser Arbeit ist die Steigerung der Effizienz in kollaborativen Anwendungen, bei gleichzeitiger Einhaltung der Sicherheitsbestimmungen. Dazu werden Montagearbeitsplätze analysiert und das Potenzial kollaborativer Roboter erarbeitet. Aktuelle Sicherheitsvorschriften werden analysiert, um die Herausforderungen einer sicheren Mensch-Roboter-Zusammenarbeit zu identifizieren. Verschiedene Methoden wie intuitive Programmierung von kollaborativen Robotern, eine effiziente Steuerung mit Human-in-the-Loop Beschränkungen und eine Hardwarelösung - der Robotic Airbag - werden präsentiert

Industrial Human-Robot Collaboration: Maximizing Performance While Maintaining Safety

For many years, separated autonomous robotic systems have been an essential component in industrial manufacturing. In particular, these heavy-payload robots perform a wide range of tasks, where high precision and repeatability is crucial. A flexible adaptation of fast changing tasks or environments as well as the interaction with humans can rather not be realized by these types of robots. Recently, a paradigm shift regarding customer demand could be observed. Short product life-cycles as well as increasing individualization of products require flexible manufacturing processes. Therefore, novel light-weight robot technology was developed, which enables the collaboration of humans and robots. In particular, highly productive robots are combined with the high flexibility of humans. However, only a few collaborative applications have been established in industry, which is mainly due to the low efficiency, i.e., large cycle times caused by safety regulations. The goal of this thesis is to maximize performance in collaborative applications, while maintaining safety. For this, assembly workplaces are analyzed, typical tasks identified, and the potential of collaborative robots is elaborated. Current safety regulations are analyzed in order to identify the challenges in safe human-robot collaboration. Then, a novel control method is presented, which enables intuitive, safe, and efficient control of robots. The Mirroring Human Arm Motions approach presents a velocity-limited trajectory generation, in particular, for orientations in quaternion space. This method is extended to an online via-point trajectory generation in order to enable an adjustment of velocity limits for guaranteeing safety in realtime. Furthermore, in collaborative applications particularly collisions with the human arm are likely to occur. Therefore, human-arm performance is analyzed and experiments similar to typical collaborative scenarios are executed, to determine the dynamic properties. By exploiting the obtained information on human arm dynamics, a novel approach to improve the performance of robot motions is presented. From the experiments, a simplified human arm model is derived, which enables the calculation of movements of the human into the path of the robot. With this approach, a maximum robot velocity depending on kinematic limitations of robots and human-in-the-loop constraints can be determined. This idea is further developed into a nonlinear optimization problem, where minimal-time motions are found and applications with low-cycle times can be realized. In order to enable flexible robot motions within the entire workspace of the robot, a generalization method using Dynamic Movement Primitives is presented. It contains a novel real-time consideration of spacial and kinematic constraints, to fulfill the requirements on safe human-robot collaboration. Experiments on a collaborative workbench prove the effectiveness of the presented methods. Finally, a novel airbag technology is proposed, which enables a protective coverage of dangerous tools and objects and protects humans against injuries, caused by a collision with the robot. The so called Robotic Airbag is inflated with pressured air to create a cushion around sharp edges of tool and object. Intrinsic safety is guaranteed, as the airbag is always inflated before initiating a robot motion. In order to exclude an affect of the tool functionality, the Robotic Airbag can be deflated whenever required. Experiments with a crash-test dummy, and finally with a volunteer, prove the functionality and compliance with current safety standards. In Summary, the presented methods in this thesis enable a significant improvement of efficiency and safety in collaborative applications

Online Motion Generation for Mirroring Human Arm Motion

Motion planning in robotics is a very large field of research. Many different approaches have been developed to create smooth trajectories for robot movement. For example there are optimization algorithms, which optimize kinematic or dynamic properties of a trajectory. Furthermore, nonlinear programming methods like e.g. optimal control, or polynomial based methods are widely used for trajectory generation. Most of these techniques are used to calculate a trajectory in advance, or they are limited to create point-to-point motions, where the robot needs to stop when switching to the next target point, especially, when interpolating in rotational space. In this paper, we combine a low-pass filter and spherical linear interpolation to realize a velocity-limited online trajectory generator for robot orientations in quaternion space. We use the developed motion generator for mirroring a human arm motion with a robot, recorded by a low frequency visual tracking. Using the proposed method, we can replicate the motion of the operator’s arm with very little delay and thereby achieve an easy-to-use interface. Furthermore, as we can strictly limit the velocity of the generated motion, the approach can safely be used in human robot collaboration applications

Intercalibration of Boreal and Tethyan timescales: the magneto-biostratigraphy of the Middle Triassic and the latest Early Triassic from Spitsbergen, Arctic Norway

An integrated bio-magnetostratigraphic study of the latest Early Triassic to the upper parts of the Middle Triassic, at Milne Edwardsfjellet in central Spitsbergen, Svalbard, allows a detailed correlation of Boreal and Tethyan biostratigraphies. The biostratigraphy consists of ammonoid and palynomorph zonations, supported by conodonts, through some 234 m of succession in two adjacent sections. The magnetostratigraphy consists of ten substantive normal–reverse polarity chrons defined by sampling at 150 stratigraphic levels. The magnetization is carried by magnetite and an unidentified magnetic sulphide, and is difficult to fully separate from a strong present-day like magnetization. The bio-magnetostratigraphy from the late Olenekian (Vendomdalen Member) is supplemented by data from nearby Vikinghøgda. The early and mid-Anisian has a high sedimentation rate, comprising over half the ca. 140-m thickness of the Botneheia Formation, whereas the late Anisian and lower Ladinian is condensed into about 20 m. The two latest Boreal Ladinian ammonoid zones are absent due to erosional truncation below the Tschermakfjellet Formation. Correlation to Tethyan bio-magnetostratigraphies shows the traditional base of the Boreal Anisian (base of G. taimyrensis Zone) precedes the base Anisian (using here definitions based on the Desli Caira section in Romania). The Boreal upper Anisian G. rotelliforme and F. nevadanus ammonoid zones correlate to most of the Tethyan Pelsonian and Illyrian substages. The base Ladinian defined in the Tethyan global boundary stratotype and point (GSSP) is closely equivalent to the traditional base of the Boreal Ladinian at the I. oleshkoi Zone. The latest Olenekian to early Anisian magnetic polarity timescale is refined using the Spitsbergen data

Soziotechnisches Assistenzsystem zur lernförderlichen Arbeitsgestaltung in der robotergestützten Montage

Dieser Beitrag der Zeitschrift Gruppe. Interaktion. Organisation. (GIO) widmet sich der lernförderlichen Gestaltung eines roboterbasierten Assistenzsystems für industrielle Montagetätigkeiten. Individualisierte Produkte, kleinere Losgrößen und beschleunigte Prozesse sind Aspekte des digitalen Wandels in der industriellen Fertigung und Teil des Leitbilds einer flexiblen Produktion. Mensch-Roboter-Kollaboration und wissensbasiertes Engineering sind aktuelle Ansätze, um diesen Anforderungen gerecht zu werden. Dieser Artikel stellt an einem Anwendungsbeispiel (Verdrahtung von Schaltschränken) einen ersten Ansatz vor, wie mittels wissensbasierter Technologien (v. a. Ontologien und deren logische Interpretation) Vorschläge zur Arbeitszuteilung zwischen Menschen und Robotern sowohl nach ökonomischen als auch nach Kriterien der humanen Arbeitsgestaltung automatisiert erstellt werden können. Zum einen können für jede Aufgabe ihre Anforderungen mit den individuellen Fähigkeiten und Stärken der Beschäftigten sowie mit denen des kollaborativen Robotersystems in einem Mixed-Skill-Konzept nach betrieblichen Kennziffern (z. B. Zeit, Qualität) abgeglichen werden, um sich so einem optimalen Produktionsablauf anzunähern. Zum anderen können dabei Aspekte einer humanen Gestaltung der Mensch- Maschine-Interaktion (MMI) berücksichtigt werden, die vordringlich mit Blick auf Lernförderlichkeit zusammengeführt werden. Lernförderlichkeit in der MMI setzt Zeit, Handlungsräume und förderliche Inhalte voraus und ist zugleich eine zunehmende Notwendigkeit, um vorausschauend auf den dynamisierten Wandel von Arbeit zu reagieren. Denn gerade mit dem Technikeinsatz ist ein starker Tätigkeitswandel in Richtung Entscheidungsträger und Problemlöser verbunden, der neben Qualifizierung und Weiterbildung auch niedrigschwelliger, arbeitsintegrierter Lerngelegenheiten bedarf. Gerade die kollaborative Robotik als Schlüsseltechnologie der flexiblen Fertigung macht es nötig, neue Konzepte für die Organisation des hybriden Zusammenwirkens von Mensch und Roboter zu entwickeln. Im Folgenden wird aufbauend auf den grundle- genden Ansatz das Konzept eines technischen Demonstrators vorgestellt, welches entlang eines empirischen Fallbeispiels entwickelt wurde. Die prototypische, technische Umsetzung basiert auf einer Arbeitsumgebung mit einem Roboterarm und zugehörigen Werkzeugen, formalen semantischen Beschreibungen der Fähigkeiten und Tätigkeiten von Menschen und Robotern sowie einer intuitiven Benutzeroberfläche, unter anderem für die individuelle Anpassung der generierten Arbeitszuteilungen

Smithian platform-bearing gondolellid conodonts from Yiwagou Section, northwestern China and implications for their geographic distribution in the Early Triassic

Abundant platform-bearing gondolellid conodonts, including Scythogondolella mosheri (Kozur and Mostler), Sc. phryna Orchard and Zonneveld, and Sc. cf. milleri (Müller), have been discovered from the Yiwagou Section of Tewo, together with Novispathodus waageni waageni (Sweet) and Nv. w. eowaageni Zhao and Orchard. This is the first report of Smithian platform-bearing gondolellids from the Paleo-Tethys region. In addition, Eurygnathodus costatus Staesche, E. hamadai(Koike), Parafurnishius xuanhanensis Yang et al., and the genera Pachycladina Staesche, Parachirognathus Clark, and Hadrodontina Staesche have also been recovered from Dienerian to Smithian strata at Yiwagou Section. Three conodont zones are established, in ascending order: Eurygnathodus costatus-E. hamadai Assemblage Zone, Novispathodus waageni-Scythogondolella mosheri Assemblage Zone, and the Pachycladina-Parachirognathus Assemblage Zone. The platform-bearing gondolellids were globally distributed just after the end-Permian mass extinction, but the formerly abundant Clarkina Kozur disappeared in the late Griesbachian. Platform-bearing gondolellids dramatically decreased to a minimum of diversity and extent in the Dienerian before recovering in the Smithian. Scythogondolella Kozur, probably a thermophilic and eurythermic genus, lived in all latitudes at this time whereas other genera did not cope with Smithian high temperatures and so became restricted to the high-latitude regions. However, the maximum temperature in the late Smithian likely caused the extinction of almost all platform-bearing gondolellids. Finally, the group returned to equatorial regions and achieved global distribution again in the cooler conditions of the late Spathian. We conclude that temperature (and to a lesser extent oxygen levels) exerted a strong control on the geographical distribution and evolution of platform-bearing gondolellids in the Early Triassic

Morphological Convergence in Forest Microfungi Provides a Proxy for Paleogene Forest Structure

Amber, fossilized plant resin from gymnosperms and angiosperms, is renowned for preserving a wide range of organisms in microscopic fidelity. These so-called amber inclusions comprise many groups of organisms, ranging from bacteria to arthropods and vertebrates. Calicioid lichens and fungi, which are from now on referred to as “calicioids,” constitute a diverse group of tiny ascomycetes with superficially similar, usually well-stalked ascomata and which often accumulate mature ascospores on top of the apothecial disk to form a true mazaedium. The aim of this study is to use all available information on the morphology and ecology of extant calicioids to reconstruct the substrate and habitat ecology of known fossil calicioids and then to use this information to open new insights into the stand structure and ecological conditions of European Paleogene amber forests. First, we introduce the morphology of extant calicioids and demonstrate that their structural features are intimately linked to habitat ecology and are instrumental for successful dispersal; we also explain the conspicuous morphological convergence between phylogenetically distant calicioid fungi. Then, we show that the adaptive traits of calicioids have not changed since at least the Eocene, and argue that their fundamental niches also have remained unchanged. Finally, we summarize what the diversity and relative abundance of fossil calicioids in amber tells us about the ecological conditions that once prevailed in European amber forests.Peer reviewe

Oxygen as a Driver of Early Arthropod Micro-Benthos Evolution

BACKGROUND: We examine the physiological and lifestyle adaptations which facilitated the emergence of ostracods as the numerically dominant Phanerozoic bivalve arthropod micro-benthos. METHODOLOGY/PRINCIPAL FINDINGS: The PO(2) of modern normoxic seawater is 21 kPa (air-equilibrated water), a level that would cause cellular damage if found in the tissues of ostracods and much other marine fauna. The PO(2) of most aquatic breathers at the cellular level is much lower, between 1 and 3 kPa. Ostracods avoid oxygen toxicity by migrating to waters which are hypoxic, or by developing metabolisms which generate high consumption of O(2). Interrogation of the Cambrian record of bivalve arthropod micro-benthos suggests a strong control on ecosystem evolution exerted by changing seawater O(2) levels. The PO(2) of air-equilibrated Cambrian-seawater is predicted to have varied between 10 and 30 kPa. Three groups of marine shelf-dwelling bivalve arthropods adopted different responses to Cambrian seawater O(2). Bradoriida evolved cardiovascular systems that favoured colonization of oxygenated marine waters. Their biodiversity declined during intervals associated with black shale deposition and marine shelf anoxia and their diversity may also have been curtailed by elevated late Cambrian (Furongian) oxygen-levels that increased the PO(2) gradient between seawater and bradoriid tissues. Phosphatocopida responded to Cambrian anoxia differently, reaching their peak during widespread seabed dysoxia of the SPICE event. They lacked a cardiovascular system and appear to have been adapted to seawater hypoxia. As latest Cambrian marine shelf waters became well oxygenated, phosphatocopids went extinct. Changing seawater oxygen-levels and the demise of much of the seabed bradoriid micro-benthos favoured a third group of arthropod micro-benthos, the ostracods. These animals adopted lifestyles that made them tolerant of changes in seawater O(2). Ostracods became the numerically dominant arthropod micro-benthos of the Phanerozoic. CONCLUSIONS/SIGNIFICANCE: Our work has implications from an evolutionary context for understanding how oxygen-level in marine ecosystems drives behaviour