A Cost Effective and Light Weight Unipolar Electroadhesion Pad Technology for Adhesion Mechanism of Wall Climbing Robot

Electroadhesion technique being employed in variety of fields of science and technology is considered as a clamping technique for wall climbing robots. The focus of this research is to present a cost effective and light weight unipolar electroadhesion pad technology for wall climbing robots (WCR) capable of lifting a reasonable weight vertically. The literature demonstrates that most of the research related electroadhesion has been performed on bipolar electrode pads. The research presented in this paper indicates that unipolar electroadhesion pad showed favourable attachment on melamine and wood substrates giving encouragement for the realisation of unipolar WCR. Design considerations along with the attachment of anti-peeling tail are also considered for the realization of WCR. The controlling mechanism for unipolar wall climbing robot was not complex. In conculsion, unipolar electroadhesion pad of copper and aluminium is a feasible technique to develop a cost effective and light weight unipolar wall climbing robot

New designs for bioinspired microstructures with adhesion to rough surfaces

Adhesion to substrates with surface roughness is a research field with many unsolved questions. A more thorough understanding of the underlying principles is important to develop new technologies with potential implications for instance in robotics, industrial automatization and wearable interfaces. Nature is a vast source of inspiration as animals have mastered climbing on various surfaces at high speed with several attachment and detachment events in a short time. In this work, new designs for dry adhesives inspired by natural blueprints are presented. Different strategies were explored to understand and tune adhesion on a range of substrates from smooth glass to polymers with skin-like roughness. Both the material properties and the geometry of the dry adhesives were utilized to improve adhesion strength. Three concepts are presented in this work: (i) composite structures with tunable interface, (ii) soft pressure sensitive adhesive layers, and (iii) funnel-shaped microstructures. This thesis aims for better understanding of the adhesion behavior as a function of several important factors including hold time, substrate material and roughness. The new concepts for bioinspired structures investigated in the present thesis will contribute to the development of performant, reversible adhesives for a variety of applications where surface roughness is involved.Adhäsion an rauen Oberflächen stellt immer noch ein Forschungsfeld mit vielen ungelösten Problemen dar. Um neue Technologien mit Bedeutung für beispielsweise die Robotik, industrielle Automatisierung und körpernahe Sensorik zu entwickeln, bedarf es eines tieferen Verständnisses der zugrunde liegenden Prinzipien. Hier stellt die Natur eine vielfältige Inspirationsquelle dar, da bestimmte Lebewesen in der Lage sind, auf unterschiedlichsten Untergründen zu haften. Im Rahmen dieser Arbeit werden der Natur nachempfundene Modelle und Lösungen zur Haftung vorgestellt. Zum Verständnis der Haftungsmechanismen und zur Optimierung der Hafteigenschaften auf einer Bandbreite von Substraten, von glattem Glas bis hin zu rauen, hautähnlichen Polymeroberflächen, wurden unterschiedliche Herangehensweisen untersucht. Zur Erhöhung der Haftkraft kamen sowohl Variationen in den verwendeten Materialien, als auch in der Geometrie der Haftstrukturen zum Einsatz. Drei Konzepte werden in dieser Arbeit vorgestellt: (i) Kompositstrukturen mit variablen Grenzflächen; (ii) weiche, drucksensitive Schichten und (iii) trichterförmige Mikrostrukturen. Es wird ein besseres Verständnis des Adhäsionsverhaltens in direktem Zusammenhang mit verschiedenen Struktur-, Substrat- und Messparametern angestrebt. Die in dieser Arbeit vorgestellten, neuen Konzepte für bioinspirierte Strukturen sollen zur Entwicklung performanter, reversibler Haftverbindungen für einen breiten Anwendungsbereich auf rauen Oberflächen beitragen.L’adhésion sur des surfaces rugueuses offre beaucoup de questions ouvertes aux chercheurs. Pour développer des technologies pionnières dans les domaines comme la robotique, automatisation industrielle et les capteurs portables, une connaissance plus détaillée des mécanismes gouvernant ce phénomène est nécessaire. La nature est une source d’inspiration vaste avec une multitude d’animaux possédant la capacité d’escalader diverses surfaces à grande vitesse. Cette thèse présente de nouveaux designs d’adhésifs secs inspirés par la nature. Différentes stratégies ont été explorées afin de comprendre et modifier l’adhésion sur des surfaces variées comme le verre poli ou des polymères avec une texture de surface ressemblant celle de la peau. Les propriétés des matériaux et la géométrie des structures ont été utilisées comme paramètres pour maximiser l’adhésion. Cette thèse comprend trois parties : (i) des structures composites avec interface variable, (ii) des films mous sensibles à la pression, et (iii) des structures en forme d’entonnoir. Les paramètres étudiés englobent entre outre le temps d’attente, le matériau du substrat et sa rugosité. Tous les concepts peuvent être raffinés et optimisé envers certaines applications. Les nouveaux concepts de structures inspirés par la nature présentés ci-dedans ont pour but de contribuer au développement d’adhésifs performants et réversibles pour une variété d’applications pour lesquelles la rugosité joue un important rôle.The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 340929 awarded to Eduard Arzt and by the German Research Foundation (Deutsche Forschungsgemeinschaft) through the grant n. HE 7498/1-1 awarded to René Hensel

Development of a Chain Climbing Robot and an Automated Ultrasound Inspection System for Mooring Chain Integrity Assessment

Mooring chains used to stabilise offshore floating platforms are often subjected to harsh environmental conditions on a daily basis, i.e. high tidal waves, storms etc. Chain breakage can lead to vessel drift and serious damage such as riser rupture, production shutdown and hydrocarbon release. Therefore, integrity assessment of chain links is vital, and regular inspection is mandatory for offshore structures. Currently, structural health monitoring of chain links is conducted using either remotely operated vehicles (ROVs), which are associated with high costs, or by manual means, which increases the risk to human operators. The development of climbing robots for mooring chain applications is still in its infancy due to the operational complexity and geometrical features of the chain. This thesis presents a Cartesian legged magnetic adhesion tracked-wheel crawler robot developed for mooring chain inspection. The crawler robot presented in this study is suitable for mooring chain climbing in air and the technique can be adapted for underwater use. The proposed robot addresses straight mooring chain climbing and a misaligned scenario that is commonly evident in in-situ conditions. The robot can be used as a platform to convey equipment, i.e. tools for non-destructive testing/evaluation applications. The application of ultrasound for in-service mooring chain inspection is still in the early stages due to lack of accessibility, in-field operational complexity and the geometrical features of mooring systems. With the advancement of robotic/automated systems (i.e. chain-climbing robotic mechanisms), interest in in-situ ultrasound inspection has increased. Currently, ultrasound inspection is confined to the weld area of the chain links. However, according to recent studies on fatigue and residual stresses, ultrasound inspection of the chain crown should be further investigated. A new automated application for ultrasonic phased-array full-matrix capture is discussed in this thesis for investigation of the chain crown. The concept of the chain-climbing robot and the inspection technique are validated with laboratory-based climbing experiments and presented in this thesis