A Dexterous Tip-extending Robot with Variable-length Shape-locking

Soft, tip-extending "vine" robots offer a unique mode of inspection and manipulation in highly constrained environments. For practicality, it is desirable that the distal end of the robot can be manipulated freely, while the body remains stationary. However, in previous vine robots, either the shape of the body was fixed after growth with no ability to manipulate the distal end, or the whole body moved together with the tip. Here, we present a concept for shape-locking that enables a vine robot to move only its distal tip, while the body is locked in place. This is achieved using two inextensible, pressurized, tip-extending, chambers that "grow" along the sides of the robot body, preserving curvature in the section where they have been deployed. The length of the locked and free sections can be varied by controlling the extension and retraction of these chambers. We present models describing this shape-locking mechanism and workspace of the robot in both free and constrained environments. We experimentally validate these models, showing an increased dexterous workspace compared to previous vine robots. Our shape-locking concept allows improved performance for vine robots, advancing the field of soft robotics for inspection and manipulation in highly constrained environments.Comment: 7 pages,10 figures. Accepted to IEEE International Conference on Rootics and Automation (ICRA) 202

A novel hydrogel-based connection mechanism for soft modular robots

Connection mechanisms are crucial in reconfigurable robots. In this work, we present a novel approach, based on the self-healing property of a hydrogel synthesized by our group, which allows us to easily attach and detach robotic modules using water as the only trigger element. Our connection mechanism does not need external energy to work and it is reversible and soft, being useful for soft modular robots. Tensile, fatigue and adhesion tests are presented to demonstrate the mechanical performance of our mechanism. Two modular soft robots, manipulator and snake, are featured to show the functionality of our approach.Los mecanismos de conexión son cruciales en los robots reconfigurables. En este trabajo, presentamos un enfoque novedoso, basado en la propiedad de autocuración de un hidrogel sintetizado por nuestro grupo, que nos permite acoplar y desacoplar fácilmente módulos robóticos utilizando el agua como como único elemento activador. Nuestro mecanismo de conexión no necesita energía externa para funcionar y es reversible y suave, siendo útil para los robots modulares blandos. Se presentan ensayos de tracción ensayos de tracción, fatiga y adherencia para demostrar el rendimiento mecánico de nuestro mecanismo. Se presentan dos robots modulares blandos, un manipulador y una serpiente, para para mostrar la funcionalidad de nuestro enfoque

Cruise Report R.V. Poseidon Cruise Nr. 291 [POS291]

Dates, Ports: 26.6.2002 (Reykjavik) – 2.7.2002 (Akureyri) – 14.7.2002 (Reykjavik), Research subject: Hydrothermal studies of Grimsey Field, volcanic studies of Kolbeinsey Ridge, Chief Scientist: Prof. Dr. Colin W. Devey, Univ. Bremen, Number of Scientists: 22 (2 legs), Project: DFG De572/14-1 Fracture Zon

Enhanced Bees Algorithm with fuzzy logic and Kalman filtering

The Bees Algorithm is a new population-based optimisation procedure which employs a combination of global exploratory and local exploitatory search. This thesis introduces an enhanced version of the Bees Algorithm which implements a fuzzy logic system for greedy selection of local search sites. The proposed fuzzy greedy selection system reduces the number of parameters needed to run the Bees Algorithm. The proposed algorithm has been applied to a number of benchmark function optimisation problems to demonstrate its robustness and self-organising ability. The Bees Algorithm in both its basic and enhanced forms has been used to optimise the parameters of a fuzzy logic controller. The purpose of the controller is to stabilise and balance an under-actuated two-link acrobatic robot (ACROBOT) in the upright position. Kalman filtering, as a fast convergence gradient-based optimisation method, is introduced as an alternative to random neighbourhood search to guide worker bees speedily towards the optima of local search sites. The proposed method has been used to tune membership functions for a fuzzy logic system. Finally, the fuzzy greedy selection system is enhanced by using multiple independent criteria to select local search sites. The enhanced fuzzy selection system has again been used with Kalman filtering to speed up the Bees Algorithm. The resulting algorithm has been applied to train a Radial Basis Function (RBF) neural network for wood defect identification. The results obtained show that the changes made to the Bees Algorithm in this research have significantly improved its performance. This is because these enhancements maintain the robust global search attribute of the Bees Algorithm and improve its local search procedure.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Seventh Annual Workshop on Space Operations Applications and Research (SOAR 1993), volume 1

This document contains papers presented at the Space Operations, Applications and Research Symposium (SOAR) Symposium hosted by NASA/Johnson Space Center (JSC) on August 3-5, 1993, and held at JSC Gilruth Recreation Center. SOAR included NASA and USAF programmatic overview, plenary session, panel discussions, panel sessions, and exhibits. It invited technical papers in support of U.S. Army, U.S. Navy, Department of Energy, NASA, and USAF programs in the following areas: robotics and telepresence, automation and intelligent systems, human factors, life support, and space maintenance and servicing. SOAR was concerned with Government-sponsored research and development relevant to aerospace operations. More than 100 technical papers, 17 exhibits, a plenary session, several panel discussions, and several keynote speeches were included in SOAR '93

MICROBE-MINERAL RELATIONSHIPS AND BIOGENIC MINERAL TRANSFORMATIONS IN ACTIVELY VENTING DEEP-SEA HYDROTHERMAL SULFIDE CHIMNEYS

This dissertation uses a combination of microbiology, mineralogy, and geochemistry to understand dissimilatory iron reduction in hyperthermophilic archaea and the role and potential impact of these and other vent microorganisms within active deep-sea hydrothermal vent chimneys. The central objective of the dissertation is to determine if mineral composition and chimney type are among the primary determinants of microbial community composition and hyperthermophilic, dissimilatory iron reducer growth, in addition to other environmental factors such as nutrient availability, temperature, pH, and chlorinity. This is done using samples and organisms collected from the Endeavour Segment of the Juan de Fuca Ridge in the northeastern Pacific Ocean. The goals of this dissertation are: 1) to correlate microbial community compositions within three Endeavour hydrothermal chimneys with their mineral compositions using mineral spectroscopic techniques that have not been applied previously to hydrothermal chimneys, 2) to characterize the growth and Fe2+ production rates and constraints of two novel hyperthermophilic iron reducers isolated from Endeavour hydrothermal chimneys, and 3) to determine the mineral end-products of these iron reducers using mineral spectroscopic techniques that have not been applied previously with hyperthermophiles. This was first done by collecting three active hydrothermal chimneys and their associated high-temperature fluids from the Endeavour Segment, Juan de Fuca Ridge to evaluate the linkages among mineralogy, fluid chemistry, and microbial community composition within the chimneys. To identify mineralogy, Mössbauer, mid-infrared thermal emission, and VNIR spectroscopies were used for the first time on vent chimneys, in addition to thin-section petrography, x-ray diffraction (XRD) and elemental analyses. A chimney from the Bastille edifice was rich in Fe-sulfide and composed primarily of chalcopyrite, marcasite, sphalerite, and pyrrhotite (i.e., type I chimney) while chimneys from the Dante and Hot Harold edifices were rich in anhydrite (type II-III chimneys). The bulk emissivity and reflectance spectroscopies corroborated petrography, XRD, and elemental analyses, demonstrating the potential of these techniques for future shipboard analysis. The microbial community within the Bastille chimney was most closely related to mesophilic and thermophilic anaerobes of the deltaproteobacteria, especially sulfate reducers, and anaerobic hyperthermophilic archaea, while those within the Dante and Hot Harold chimneys were most closely related to mesophilic and thermophilic aerobes of the beta-, gamma- and epsilonproteobacteria. Numerical modeling of energy availability from redox reactions in vent fluids suggests that aerobic oxidation of sulfide and methane should be the predominant autotrophic microbial metabolisms at 25°C and 55°C and that anaerobic oxidation of methane should prevail at 80°C. While the microbial community compositions of all three chimneys show aerobic sulfide-oxidizing epsilonproteobacteria, the predominance of mesophilic sulfate reducers in the Bastille chimney suggests that type I chimneys may promote anaerobic metabolisms. The next two goals, namely characterizing the growth and Fe2+ production rates and constraints of two novel hyperthermophilic iron reducers isolated from Endeavour hydrothermal chimneys, and determining their mineral end-products using mineral spectroscopic techniques that have not been applied previously with hyperthermophiles, were carried out in parallel. Hyperthermophilic iron reducers are common in hydrothermal chimneys found along the Endeavour Segment in the northeastern Pacific Ocean based on culture-dependent estimates. However, information on the availability of Fe(III) (oxyhydr)oxides within these chimneys, the types of Fe(III) (oxyhydr)oxides utilized by the organisms, rates and environmental constraints of hyperthermophilic iron reduction, and mineral end products are needed to determine their biogeochemical significance and are addressed in this study. Thin-section petrography on the interior of a hydrothermal chimney from the Dante edifice at Endeavour showed a thin coat of Fe(III) (oxyhydr)oxide associated with amorphous silica on the exposed outer surfaces of pyrrhotite, sphalerite and chalcopyrite in pore spaces, along with anhydrite precipitation in the pores that is indicative of seawater ingress. The iron sulfide minerals were likely oxidized to Fe(III) (oxyhydr)oxide with increasing pH and Eh due to cooling and seawater exposure, providing reactants for bioreduction. Culture-dependent estimates of hyperthermophilic iron reducer abundances in this sample were 1,740 and 10 cells per gram (dry weight) of material from the outer surface and the marcasite-sphalerite-rich interior, respectively. Two hyperthermophilic iron reducers, Hyperthermus sp. Ro04 and Pyrodictium sp. Su06, were isolated from other active hydrothermal chimneys on the Endeavour Segment. Strain Ro04T grew on peptides, reduced poorly crystalline iron oxide to black ferromagnetic magnetite and produced acetate and minor amounts of ethanol. It did not grow on any other terminal electron acceptor or purely by fermentation. Strain Su06T also catabolized peptides but only when H2 was present and reduced poorly crystalline iron oxide to magnetite and nitrate to N2. They both grew between 82°C and 97°C (Topt 90-92°C) and pH 5.0 and 9.0, but strain Ro04T had a pH optimum of 8.0 while strain Su06T had a pH optimum of 5.0. 16S rRNA gene sequence similarity analysis indicated they are 98.4% identical to each other and are most closely related (\u3e98%) to Hyperthermus butylicus DSM 5456T, Pyrodictium abyssi DSM 6158T, Pyrodictium occultum DSM 2709T and Pyrodictium brockii DSM 2708T. The complete genome for Strain Su06 was obtained and genome comparisons done in silico between Strain Su06T against Hyperthermus butylicus and Pyrolobus fumarii, revealed that Strain Su06 is a novel species. Strain Ro04T had growth characteristics most similar to H. butylicus while strain Su06 was more similar to P. abyssi. However, the ability of the strains to reduce iron and their inability to reduce sulfur compounds clearly distinguished them from all of their closest relatives. Phylogenetic, genomic, and phenotypic data indicate that strain Ro04T is novel species of Hyperthermus and strain Su06T is a novel species of Pyrodictium. The name Hyperthermus hephaesti is proposed for strain Ro04T and Pyrodictium delaneyi is proposed for Su06T. Mössbauer spectroscopy of the iron oxides before and after growth demonstrated that both organisms form nanophase (nm) magnetite [Fe3O4] from laboratory-synthesized ferrihydrite [Fe10O14(OH)2] with no detectable mineral intermediates. They produced up to 40 mM Fe2+ in a growth-dependent manner while all abiotic and biotic controls produced \u3c 3 mM Fe2+. Hyperthermophilic iron reducers may have a growth advantage over other hyperthermophiles in hydrothermal systems that are mildly acidic where mineral weathering at elevated temperatures occurs

Enhanced Bees Algorithm with fuzzy logic and Kalman filtering

The Bees Algorithm is a new population-based optimisation procedure which employs a combination of global exploratory and local exploitatory search. This thesis introduces an enhanced version of the Bees Algorithm which implements a fuzzy logic system for greedy selection of local search sites. The proposed fuzzy greedy selection system reduces the number of parameters needed to run the Bees Algorithm. The proposed algorithm has been applied to a number of benchmark function optimisation problems to demonstrate its robustness and self-organising ability. The Bees Algorithm in both its basic and enhanced forms has been used to optimise the parameters of a fuzzy logic controller. The purpose of the controller is to stabilise and balance an under-actuated two-link acrobatic robot (ACROBOT) in the upright position. Kalman filtering, as a fast convergence gradient-based optimisation method, is introduced as an alternative to random neighbourhood search to guide worker bees speedily towards the optima of local search sites. The proposed method has been used to tune membership functions for a fuzzy logic system. Finally, the fuzzy greedy selection system is enhanced by using multiple independent criteria to select local search sites. The enhanced fuzzy selection system has again been used with Kalman filtering to speed up the Bees Algorithm. The resulting algorithm has been applied to train a Radial Basis Function (RBF) neural network for wood defect identification. The results obtained show that the changes made to the Bees Algorithm in this research have significantly improved its performance. This is because these enhancements maintain the robust global search attribute of the Bees Algorithm and improve its local search procedure