Limpet II: A Modular, Untethered Soft Robot

The ability to navigate complex unstructured environments and carry out inspection tasks requires robots to be capable of climbing inclined surfaces and to be equipped with a sensor payload. These features are desirable for robots that are used to inspect and monitor offshore energy platforms. Existing climbing robots mostly use rigid actuators, and robots that use soft actuators are not fully untethered yet. Another major problem with current climbing robots is that they are not built in a modular fashion, which makes it harder to adapt the system to new tasks, to repair the system, and to replace and reconfigure modules. This work presents a 450 g and a 250 × 250 × 140 mm modular, untethered hybrid hard/soft robot—Limpet II. The Limpet II uses a hybrid electromagnetic module as its core module to allow adhesion and locomotion capabilities. The adhesion capability is based on negative pressure adhesion utilizing suction cups. The locomotion capability is based on slip-stick locomotion. The Limpet II also has a sensor payload with nine different sensing modalities, which can be used to inspect and monitor offshore structures and the conditions surrounding them. Since the Limpet II is designed as a modular system, the modules can be reconfigured to achieve multiple tasks. To demonstrate its potential for inspection of offshore platforms, we show that the Limpet II is capable of responding to different sensory inputs, repositioning itself within its environment, adhering to structures made of different materials, and climbing inclined surfaces

Functional surface microstructures inspired by nature – From adhesion and wetting principles to sustainable new devices

In the course of evolution nature has arrived at startling materials solutions to ensure survival. Investigations into biological surfaces, ranging from plants, insects and geckos to aquatic animals, have inspired the design of intricate surface patterns to create useful functionalities. This paper reviews the fundamental interaction mechanisms of such micropatterns with liquids, solids, and soft matter such as skin for control of wetting, self-cleaning, anti-fouling, adhesion, skin adherence, and sensing. Compared to conventional chemical strategies, the paradigm of micropatterning enables solutions with superior resource efficiency and sustainability. Associated applications range from water management and robotics to future health monitoring devices. We finally provide an overview of the relevant patterning methods as an appendix

Functional surface microstructures inspired by nature : From adhesion and wetting principles to sustainable new devices

In the course of evolution nature has arrived at startling materials solutions to ensure survival. Investigations into biological surfaces, ranging from plants, insects and geckos to aquatic animals, have inspired the design of intricate surface patterns to create useful functionalities. This paper reviews the fundamental interaction mechanisms of such micropatterns with liquids, solids, and soft matter such as skin for control of wetting, self-cleaning, anti-fouling, adhesion, skin adherence, and sensing. Compared to conventional chemical strategies, the paradigm of micropatterning enables solutions with superior resource efficiency and sustainability. Associated applications range from water management and robotics to future health monitoring devices. We finally provide an overview of the relevant patterning methods as an appendix

Autonomous and reversible adhesion using elastomeric suction cups for in-vivo medical treatments

Remotely controllable and reversible adhesion is highly desirable for surgical operations: it can provide the possibility of non-invasive surgery, flexibility in fixing a patch and surgical manipulation via sticking. In our previous work, we developed a remotely controllable, ingestible, and deployable pill for use as a patch in the human stomach. In this study, we focus on magnetically facilitated reversible adhesion and develop a suction-based adhesive mechanism as a solution for non-invasive and autonomous adhesion of patches. We present the design, model, and fabrication of a magnet-embedded elastomeric suction cup. The suction cup can be localised, navigated, and activated or deactivated in an autonomous way; all realised magnetically with a pre-programmed fashion. The use of the adhesion mechanism is demonstrated for anchoring and carrying, for patching an internal organ surface and for an object removal, respectively

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

Soft Robotic Grippers

Advances in soft robotics, materials science, and stretchable electronics have enabled rapid progress in soft grippers. Here, a critical overview of soft robotic grippers is presented, covering different material sets, physical principles, and device architectures. Soft gripping can be categorized into three technologies, enabling grasping by: a) actuation, b) controlled stiffness, and c) controlled adhesion. A comprehensive review of each type is presented. Compared to rigid grippers, end-effectors fabricated from flexible and soft components can often grasp or manipulate a larger variety of objects. Such grippers are an example of morphological computation, where control complexity is greatly reduced by material softness and mechanical compliance. Advanced materials and soft components, in particular silicone elastomers, shape memory materials, and active polymers and gels, are increasingly investigated for the design of lighter, simpler, and more universal grippers, using the inherent functionality of the materials. Embedding stretchable distributed sensors in or on soft grippers greatly enhances the ways in which the grippers interact with objects. Challenges for soft grippers include miniaturization, robustness, speed, integration of sensing, and control. Improved materials, processing methods, and sensing play an important role in future research

Dynamic digital shearography for on-board robotic non-destructive testing of wind turbine blades

Structural integrity plays a critical role in development of infrastructural construction and support facilities. During the lifespan of most large-scale equipment, condition monitoring and periodic inspection is indispensable for ensuring structural health and evaluation of service condition. Wind turbine blades are the most important component of wind turbines and demands regular inspection to detect defects, which often occur underneath a blade surface. Current methods used to inspect wind turbine blades include to send NDT operators to climb the tower for on-site inspection of the blades’ surface or to dismantle the blades for inspection on the ground. These approaches are time-consuming, costly and pose risks of injury to human inspectors. Thus, it is necessary to develop a technological method for wind turbine blade on-site inspection of wind turbine blades. Digital shearography based on laser interferometry has demonstrated its prominent capability for inspecting composite material which is the main material used in the construction of wind turbine blades. Shearography is a ramification of holography interferometry and is more efficient to be used as a non-destructive testing (NDT) technique owing to its improved robustness and sensitivity to surface displacement. Robotic climbers, on the other hand, have recently drawn significant interest in NDT applications to replace human inspectors in extreme conditions. Thus, this thesis presents investigations into the development of a robotic NDT method using digital shearography for on-site inspection of wind turbine blades. The development of the shearography unit with correlation fringe pattern acquisition and the integration of this unit with the robotic climber adhering to wind turbine blades using vacuum generators are described in this thesis. The successful conduction of the indoor and outdoor trails for the integrated system verifies that shearography holds the ability to be used as an NDT tool for on-site wind turbine blade inspection, and that the climbing robot is able to access most areas of a wind turbine blade and stabilise itself to remove the impact on the shearography of the high frequencies from the climber’s vacuum motor and the low frequencies from the blade swing. Temporal phase shift shearography, and the fast phase map acquisition methods with less steps are evaluated in the thesis. Experiments are performed in lab with phase maps obtained using different algorithms. Apart from the conventional 4 steps and 3 steps phase shift algorithms, the modified 4+1 and 3+1 temporal phase shifting algorithms are developed for more suitability of semi-dynamic inspection by firstly calculating the correlation fringes and followed by the phase map calculations. The results of these modified methods are compared with the conventional 4 steps and 3 steps methods and are shown with equal qualities. Moreover, the reduced steps of phase shifting, i.e., 2+1 phase shifting methods are conducted for semi-dynamic phase map acquisition. It is found that the temporal phase shifting methods are not suitable for dynamic wind turbine blade inspection, however, the fast semi-dynamic temporal phase shift algorithms are able to produce phase maps with lower clarity. Pixelated spatial phase shift shearography is developed to remedy the limitation of temporal phase shift techniques. It adopts a micro-polarization sensor in the complementary metal oxide semiconductor (CMOS) camera, two linear polarizers, and a quarter waveplate as a new arrangement of optical path to replace the piezoelectric transducer stepper as the phase stepper. Three algorithms are introduced based on this novel developed system. Additionally, the site of view is enlarged for upgrading of the system. The development of the pixelated spatial phase shift shearography has mitigated the static processing limitation on temporal phase shift shearography, which caters for the demands of on-site NDT operation. At the same time, it remedies the current real-time shearography system which is not able to produce phase distributions for further quantitative analysis. The new developed pixelated spatial phase shift shearography system is thus more suitable for WTB on board inspection than both conventional and less-steps temporal phase shift shearography system. The field of view enlargement optimisation in the new developed spatial phase shift system indirectly reduces the distance for the inspection process and meanwhile enlarges the site of view, which consequently reduces the weight and structural complexity of the robotic-shearography integration system. The research addresses and resolves the difficulty of on-board wind turbine blade inspection with a novel robotic NDT approach using digital shearography. The approach is significant for real world industrial applications. Moreover, through the temporal and spatial phase shift evaluation, the research proves the feasibility of dynamically obtaining phase maps by the shearography system for further quantitative analysis without using temporal phase shift devices

Proper maintenance way for the multifunctional windows

Recent developments have helped create windows that can fulfill their contrary functions effectively in addition to generating energy, which are known as multifunctional windows. Permanent maintenance is required for windows to achieve their functions properly, but the current window cleaning methods can harm and are not appropriate for the recently developed multifunctional windows. The author presents a suggested multifunctional window and sheds light on the disadvantages that could be accomplished when using the current methods to clean it. Using analytical and logical methods, this paper shows the proper way of the multifunctional window maintenance. This way depends on the self-cleaning features. The author proposes a solution for the disadvantages that could accompany that features. The main result is the validity of a successful multifunctional window that can be maintained with minimum disadvantages and maximum efficiency. Therefore, this study contributes to the window industry by presenting the proper way of maintaining multifunctional windows. Thus, future maintenance research should be redirected properly to conserve and benefit the efforts spent in impropriate directions and technologie

Climbing and Walking Robots

With the advancement of technology, new exciting approaches enable us to render mobile robotic systems more versatile, robust and cost-efficient. Some researchers combine climbing and walking techniques with a modular approach, a reconfigurable approach, or a swarm approach to realize novel prototypes as flexible mobile robotic platforms featuring all necessary locomotion capabilities. The purpose of this book is to provide an overview of the latest wide-range achievements in climbing and walking robotic technology to researchers, scientists, and engineers throughout the world. Different aspects including control simulation, locomotion realization, methodology, and system integration are presented from the scientific and from the technical point of view. This book consists of two main parts, one dealing with walking robots, the second with climbing robots. The content is also grouped by theoretical research and applicative realization. Every chapter offers a considerable amount of interesting and useful information