Development of an Instrumented and Powered Exoskeleton for the Rehabilitation of the Hand

With improvements in actuation technology and sensory systems, it is becoming increasingly feasible to create powered exoskeletal garments that can assist with the movement of human limbs. This class of robotics referred to as human-machine interfaces will one day be used for the rehabilitation of paralysed, damaged or weak upper and lower extremities. The focus of this project was the development of an exoskeletal interface for the rehabilitation of the hands. A novel sensor was designed for use in such a device. The sensor uses simple optical mechanisms centred on a spring to measure force and position simultaneously. In addition, the sensor introduces an elastic element between the actuator and its corresponding hand joint. This will allow series elastic actuation (SEA) to improve control and safely of the system. The Hand Rehabilitation Device requires multiple actuators. To stay within volume and weight constraints, it is therefore imperative to reduce the size, mass and efficiency of each actuator without losing power. A method was devised that allows small efficient actuating subunits to work together and produce a combined collective output. This work summation method was successfully implemented with Shape Memory Alloy (SMA) based actuators. The actuation, sensory, control system and human-machine interface concepts proposed were evaluated together using a single-joint electromechanical harness. This experimental setup was used with volunteer subjects to assess the potentials of a full-hand device to be used for therapy, assessment and function of the hand. The Rehabilitation Glove aims to bring significant new benefits for improving hand function, an important aspect of human independence. Furthermore, the developments in this project may one day be used for other parts of the body helping bring human-machine interface technology into the fields of rehabilitation and therapy

Application of precision engineering for nanometre focussing of hard X-rays in synchrotron beam lines

This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University.Many modern synchrotron beamlines are able to focus X-rays to a few microns in size. Although the technology to achieve this is well established, performing routine experiments with such beams is still time consuming and requires careful set up. Furthermore there is a need to be able to carry out experiments using hard X-ray beams with even smaller beams of between 100nm and 10nm. There are focussing optics that are able to do this but integrating these optics into a stable and a usable experimental set up are challenging. Experiments can often take some hours and any change in position of the beam on the sample will adversely affect the quality of the results. Experiments will often require scanning of the beam across the sample and so mechanisms suitable for high resolution but stable scanning are required. Performing routine experiments with nanometre sized beams requires mechanical systems to be able to position the sample, focussing optics, detectors and diagnostics with significantly higher levels of stability and motion resolution than is required from so called micro focus beam lines. This dissertation critically reviews precision engineering and associated technologies that are relevant for building nano focus beamlines, and the following key issues are explored: • Long term position stability due to thermal effects • Short term position stability due to vibration • Position motion with nanometre incremental motion • Results of some tests are presented and recommendations given. Some test results are presented and guidance on designing nano focus beamlines presented.Diamond Light Sourc

A cooling system for s.m.a. (shape memory alloy)based on the use of peltier cells

The aim of this thesis has been the study and the implementation of an innovative cooling system for S.M.A. (Shape Memory Alloy) material by using a Peltier cell. This system has demonstrated a consistent cooling time reduction during the application and so that the solution adopted has confirmed that it can be used for a better operability of the S.M.A. material during the cooling phase. After an accurate selection of possible cooling system to be adopted on these materials the better choice in terms of efficiency and energy consumption reduction has converged on Peltier cell design development. In this context for our research three investigation have been conducted. The first one has concerned an analytic investigation in order to understand the phenomenology and the terms involved during the heat exchange. After this study a numerical investigation through a Finite Element approach by commercial software has been carried out. Also an experimental investigation has been conducted, at the CIRA Smart Structure Laboratory, in order to verify the results obtained by the numerical prediction. The set-up with the Peltier cell used as heater and cooler of the S.M.A. has confirmed the soundness of the solution adopted. Finally, a correlation between numerical and experimental results have been presented demonstrating the validity of the obtained results through the developed investigations. This system, composed of Peltier cell has confirmed also an energy consumption reduction because the cell has been used for heating and cooling phase without additional system as resistive system (Joule effect). This project shall be also industrial involvement in a new cost cut down point of vie

Conference on Thermal Issues in Machine Tools: Proceedings

Inhomogeneous and changing temperature distributions in machine tools lead to sometimes considerable quality problems in the manufacturing process. In addition, the switching on and off of aggregates, for example, leads to further fluctuations in the temperature field of machine tools. More than 100 specialists discussed these and other topics from the field of thermal research at the 1st Conference on Termal Issues in Machine Tools in Dresden from 22 to 23 March.:Efficient modelling and computation of structure-variable thermal behavior of machine tools S. Schroeder, A. Galant, B. Kauschinger, M. Beitelschmidt Parameter identification software for various thermal model types B. Hensel, S. Schroeder, K. Kabitzsch Minimising thermal error issues on turning centre M. Mareš, O. Horejš, J. Hornych The methods for controlled thermal deformations in machine tools A. P. Kuznetsov, H.-J. Koriath, A.O. Dorozhko Efficient FE-modelling of the thermo-elastic behaviour of a machine tool slide in lightweight design C. Peukert, J. Müller, M. Merx, A. Galant, A. Fickert, B. Zhou, S. Städtler, S. Ihlenfeldt, M. Beitelschmidt Development of a dynamic model for simulation of a thermoelectric self-cooling system for linear direct drives in machine tools E. Uhlmann, L. Prasol, S.Thom, S. Salein, R. Wiese System modelling and control concepts of different cooling system structures for machine tools J. Popken, L. Shabi, J. Weber, J. Weber The electric drive as a thermo-energetic black box S. Winkler, R. Werner Thermal error compensation on linear direct drive based on latent heat storage I. Voigt, S. Winkler, R. Werner, A. Bucht, W.-G. Drossel Industrial relevance and causes of thermal issues in machine tools M. Putz, C. Richter, J. Regel, M. Bräunig Clustering by optimal subsets to describe environment interdependencies J. Glänzel, R. Unger, S. Ihlenfeldt Using meta models for enclosures in machine tools F. Pavliček, D. P. Pamies, J. Mayr, S. Züst, P. Blaser, P. Hernández-Becerro, K. Wegener Model order reduction of thermal models of machine tools with varying boundary conditions P. Hernández-Becerro, J. Mayr, P. Blaser, F. Pavliček, K. Wegener Effectiveness of modelling the thermal behaviour of the ball screw unit with moving heat sources taken into account J. Jedrzejewski, Z. Kowal, W. Kwasny, Z. Winiarski Analyzing and optimizing the fluidic tempering of machine tool frames A. Hellmich, J. Glänzel, A. Pierer Thermo-mechanical interactions in hot stamping L. Penter, N. Pierschel Experimental analysis of the heat flux into the grinding tool in creep feed grinding with CBN abrasives C. Wrobel, D. Trauth, P. Mattfeld, F. Klocke Development of multidimensional characteristic diagrams for the real-time correction of thermally caused TCP-displacements in precise machining M. Putz, C. Oppermann, M. Bräunig Measurement of near cutting edge temperatures in the single point diamond turning process E. Uhlmann, D. Oberschmidt, S. Frenzel, J. Polte Investigation of heat flows during the milling processes through infrared thermography and inverse modelling T. Helmig, T. Augspurger, Y. Frekers, B. Döbbeler, F. Klocke, R. Kneer Thermally induced displacements of machine tool structure, tool and workpiece due to cutting processes O. Horejš, M. Mareš, J. Hornych A new calibration approach for a grey-box model for thermal error compensation of a C-Axis C. Brecher, R. Spierling, M. Fey Investigation of passive torque of oil-air lubricated angular contact ball bearing and its modelling J. Kekula, M. Sulitka, P. Kolář, P. Kohút, J. Shim, C. H. Park, J. Hwang Cooling strategy for motorized spindle based on energy and power criterion to reduce thermal errors S. Grama, A. N. Badhe, A. Mathur Cooling potential of heat pipes and heat exchangers within a machine tool spindleo B. Denkena, B. Bergman, H. Klemme, D. Dahlmann Structure model based correction of machine tools X. Thiem, B. Kauschinger, S. Ihlenfeldt Optimal temperature probe location for the compensation of transient thermal errors G. Aguirre, J. Cilla, J. Otaegi, H. Urreta Adaptive learning control for thermal error compensation on 5-axis machine tools with sudden boundary condition changes P. Blaser, J. Mayr, F. Pavliček, P. Hernández-Becerro, K. Wegener Hybrid correction of thermal errors using temperature and deformation sensors C. Naumann, C. Brecher, C. Baum, F. Tzanetos, S. Ihlenfeldt, M. Putz Optimal sensor placement based on model order reduction P. Benner, R. Herzog, N. Lang, I. Riedel, J. Saak Workpiece temperature measurement and stabilization prior to dimensional measurement N. S. Mian, S. Fletcher, A. P. Longstaff Measurement of test pieces for thermal induced displacements on milling machines H. Höfer, H. Wiemer Model reduction for thermally induced deformation compensation of metrology frames J. v. d. Boom Local heat transfer measurement A. Kuntze, S. Odenbach, W. Uffrecht Thermal error compensation of 5-axis machine tools using a staggered modelling approach J. Mayr, T. Tiberini. P. Blaser, K. Wegener Design of a Photogrammetric Measurement System for Displacement and Deformation on Machine Tools M. Riedel, J. Deutsch, J. Müller. S. Ihlenfeldt Thermography on Machine Tools M. Riedel, J. Deutsch, J. Müller, S. Ihlenfeldt Test piece for thermal investigations of 5-axis machine tolls by on-machine measurement M. Wiesener. P. Blaser, S. Böhl, J. Mayr, K. Wegene

Proceeding Of Mechanical Engineering Research Day 2016 (MERD’16)

This Open Access e-Proceeding contains a compilation of 105 selected papers from the Mechanical Engineering Research Day 2016 (MERD’16) event, which is held in Kampus Teknologi, Universiti Teknikal Malaysia Melaka (UTeM) - Melaka, Malaysia, on 31 March 2016. The theme chosen for this event is ‘IDEA. INSPIRE. INNOVATE’. It was gratifying to all of us when the response for MERD’16 is overwhelming as the technical committees received more than 200 submissions from various areas of mechanical engineering. After a peer-review process, the editors have accepted 105 papers for the e-proceeding that cover 7 main themes. This open access e-Proceeding can be viewed or downloaded at www3.utem.edu.my/care/proceedings. We hope that these proceeding will serve as a valuable reference for researchers. With the large number of submissions from the researchers in other faculties, the event has achieved its main objective which is to bring together educators, researchers and practitioners to share their findings and perhaps sustaining the research culture in the university. The topics of MERD’16 are based on a combination of fundamental researches, advanced research methodologies and application technologies. As the editor-in-chief, we would like to express our gratitude to the editorial board and fellow review members for their tireless effort in compiling and reviewing the selected papers for this proceeding. We would also like to extend our great appreciation to the members of the Publication Committee and Secretariat for their excellent cooperation in preparing the proceeding of MERD’16

Long term stability of silicide based thermoelectric materials and modules

Silicide-based thermoelectric generators are potential candidates for waste heat recovery at temperatures below 500  C. For the last two decades, the conversion efficiency of modules based on n-type magnesium silicides and p-type higher manganese silicide has improved significantly. However, the conditions in which thermoelectric generators operate (for example, remote areas in the oil, gas, and telecommunication industries, in automobiles, etc.) are harsh (corrosive, for example) and hostile (due to thermal instability). In this project, there was much focus on the stability of the thermoelectric modules, with special interest given to oxidation of the thermoelectric materials and module stability. The thermal oxidation studies were conducted on higher manganese silicide alloys; the studies mainly investigated the effect of the alloys’ composition, consolidation techniques and the operational atmosphere’s effect on their oxidation potential. Moreover, the choice of matching electrodes and good bonding technology for the module assembly was the ultimate step before finally testing the actual performance and stability of the module over an extended period. The thorough oxidation studies conducted in this thesis revealed the importance of different production processes for the higher manganese silicide thermoelectric materials on the oxidation robustness of the alloys. The study showed that the purity (fewer impurities) of the raw elements and optimal doping level are among the key factors for the alloys to resist oxidation by growing a protective SiO2 protective oxide layer. Moreover, it was also shown that powder consolidation by spark plasma sintering produced stronger bulk pellets, and mechanical strength played a key role in passive oxidation. During the module’s contacts design, silver electrodes and solid liquid interdiffusion bonding technology were used. The contact resistance of the assembled modules were measured using an automated point contact measurement test rig. On the magnesium silicide the specific contact resistance was on average 0.17 m cm2 with 2.1% standard deviation. The higher manganese silicide’s contact interface, on the other hand, the results were dispersed along the bond, where 0.07 m cm2 was the lowest value and 1.12 m cm2 the highest (81.3% standard deviation). Finally, the module stability was investigated by testing the performance of the assembled modules. The tested modules produced up to 7.4mW/cm2 power density at 400  C and sustained more than 300 thermal cycles. The gradual degradation was found to mainly originate from the mechanical failure of the contact interfaces and oxidation of the n-type magnesium silicide relative to the p-type material. Applying a high-temperature coating did not reduce the degradation rate, which showed that it would be better to encapsulate the modules to count-act the effect of oxidation.publishedVersio

Superconducting non-contact linear slider for precision positioning in cryogenic environments

In this thesis, a novel device for precision positioning in a long stroke suitable for cryogenics environments has been proposed, designed, built and tested. The device is based on superconducting magnetic levitation. A set of high temperature superconductors allows a long permanent magnet to levitate stably over them. Furthermore, due to the high translational symmetry of the magnetic field applied on the superconductors for any position of the slider in its path, the superconductors not only provide stable levitation to the slider, but al so guide it. Therefore, a sliding kinematic pair is established between the permanent magnet and the superconductors. Finally, using a pair of coils, the position of the slider can be controlled with an open-Ioop control strategy of the current in the coils with nanometre resolution and reduced power consumption. Besides, a set of design rules has been proposed and experimentally verified at 77 K. Parameters of the performance of the mechanism such as the stroke, sensitivity, stiffness, natural frequency, run outs or the power consumption can be modified and optimized by an appropriate designo After this, two prototypes of a long stroke nanopositioner based on these design rules have been built and tested in a relevant environment (T~15 K, in a high vacuum < 10⁻⁶ Pa). Nanometre resolution in the positioning of a mass of about 170 g has been demonstrated in a stroke up to 18 mm. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------En esta tesis doctoral se propone, diseña, construye y demuestra un dispositivo de alta resolución para posicionado en una carrera larga para entornos criogénicos. Este dispositivo está basado en levitación magnética superconductora de manera que, un conjunto de superconductores de alta temperatura (superconductores de tipo II) permiten a un imán permanente levitar de manera estable sobre ellos y, al mismo tiempo, ser guiado. De hecho, se establece un par cinemático de deslizamiento entre el imán y los superconductores gracias a la alta simetría traslacional del campo magnético aplicado en estos últimos. Además, la posición de la deslizadera puede ser controlada mediante una estrategia de control en bucle abierto de la corriente circulante en un par de bobinas diseñadas específicamente para esta tarea, obteniéndose una excelente resolución y un consumo de energía muy reducido. Así mismo, se proponen una serie de reglas de diseño que fueron verificadas a una temperatura de operación de 77 K. Estas reglas demuestran que hay una serie de parámetros característicos del desempeño del mecanismo como la sensibilidad, la rigidez, la frecuencia natural, las desviaciones o el consumo energético que pueden ser modificados mediante un diseño apropiado. Tras obtener estas reglas de diseño, un par de prototipos de un nanoposicionador de larga carrera han sido diseñados en consecuenCIa, construidos y probados en un ambiente relevante (T ~ 15 K, alto vacío < 10⁻⁶ Pa). Una resolución nanométrica en el posicionamiento de una masa de 170 gramos ha sido demostrada en una carrera de hasta 18 mm

NASA Tech Briefs, March 2011

Topics covered include: Optimal Tuner Selection for Kalman-Filter-Based Aircraft Engine Performance Estimation; Airborne Radar Interferometric Repeat-Pass Processing; Plug-and-Play Environmental Monitoring Spacecraft Subsystem; Power-Combined GaN Amplifier with 2.28-W Output Power at 87 GHz; Wallops Ship Surveillance System; Source Lines Counter (SLiC) Version 4.0; Guidance, Navigation, and Control Program; Single-Frame Terrain Mapping Software for Robotic Vehicles; Auto Draw from Excel Input Files; Observation Scheduling System; CFDP for Interplanetary Overlay Network; X-Windows Widget for Image Display; Binary-Signal Recovery; Volumetric 3D Display System with Static Screen; MMIC Replacement for Gunn Diode Oscillators; Feature Acquisition with Imbalanced Training Data; Mount Protects Thin-Walled Glass or Ceramic Tubes from Large Thermal and Vibration Loads; Carbon Nanotube-Based Structural Health Monitoring Sensors; Wireless Inductive Power Device Suppresses Blade Vibrations; Safe, Advanced, Adaptable Isolation System Eliminates the Need for Critical Lifts; Anti-Rotation Device Releasable by Insertion of a Tool; A Magnetically Coupled Cryogenic Pump; Single Piezo-Actuator Rotary-Hammering Drill; Fire-Retardant Polymeric Additives; Catalytic Generation of Lift Gases for Balloons; Ionic Liquids to Replace Hydrazine; Variable Emittance Electrochromics Using Ionic Electrolytes and Low Solar Absorptance Coatings; Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger; Multi-Mission Power Analysis Tool; Correction for Self-Heating When Using Thermometers as Heaters in Precision Control Applications; Gravitational Wave Detection with Single-Laser Atom Interferometers; Titanium Alloy Strong Back for IXO Mirror Segments; Improved Ambient Pressure Pyroelectric Ion Source; Multi-Modal Image Registration and Matching for Localization of a Balloon on Titan; Entanglement in Quantum-Classical Hybrid; Algorithm for Autonomous Landing; Quantum-Classical Hybrid for Information Processing; Small-Scale Dissipation in Binary-Species Transitional Mixing Layers; Superpixel-Augmented Endmember Detection for Hyperspectral Images; Coding for Parallel Links to Maximize the Expected Value of Decodable Messages; and Microwave Tissue Soldering for Immediate Wound Closure

Aerosol-Jet Printed Nanocomposites for Flexible and Stretchable Thermoelectric Generators

Converting waste heat from the environment into usable electricity, via thermoelectric generators (TEGs) based on thermoelectric (TE) materials, is predicted to be one of the most promising renewable energy solutions of the future. TE materials produce a current when subjected to a temperature gradient as a result of the Seebeck effect, and are characterised by a TE figure of merit, ZT = S2σT/κ, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the operating temperature, and κ is the thermal conductivity. TEGs can be used as an energy source for ‘small-power’ applications, such as wireless sensors and wearable devices. Nonetheless, traditional inorganic TE materials pose significant challenges owing to their high cost, toxicity, scarcity, and brittleness, particularly when it comes to applications requiring flexibility and/or stretchability. On the other hand, organic TE polymers are less expensive, environmentally friendly, and flexible. However, they typically suffer from poor TE performance due to their comparatively low S and σ. This thesis therefore seeks to explore solutions for high-performance and mechanically conformable TEGs based on organic-inorganic TE nanocomposites, adopting a material engineering approach to enhancing TE properties while ensuring the flexibility and/or stretchability of TEGs. In this work, a flexible and robust TEG based on a novel hybrid nanocomposite structure for harvesting energy from low-grade waste heat, has been successfully fabricated via a customised and scalable aerosol-jet printing (AJP) technique. Firstly, Bi2Te3 nanoparticles and Sb2Te3 nanoflakes were fabricated using a solvothermal synthesis approach, and their resulting morphological and microstructural properties were studied. They were then incorporated into a conducting polymer matrix poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) via the AJP method, resulting in well-dispersed TE nanocomposites on flexible polyimide substrates. These TE nanocomposites comprised Bi2Te3/Sb2Te3 nano-inclusions with higher S and σ embedded within a polymeric PEDOT:PSS matrix having lower κ. The compositions were dynamically tuned and controlled by the in-house developed in situ mixing method to optimise the resulting power factor (PF = S2σ). The AJP technique used in this work allows functional materials to be printed from inks with a wide range of viscosities and constituent particle sizes and shapes. The morphological and TE properties of AJ-printed nanocomposite structures were then evaluated as a function of the composition so that optimum ink formulation and printing conditions could be found to maximise the final TE performance. Importantly, these TE nanocomposites were found to be particularly stable and robust upon repeated flexing. They can be directly integrated into high-performance TEGs with minimal post-possessing treatment, making them particularly suitable for flexible TE applications. Subsequently, multiwall carbon nanotubes (MWCNTs) were introduced to enhance σ of AJ-printed nanocomposites, thereby achieving even higher PF values. A novel in situ mixing method was capable of simultaneously incorporating high-S Sb2Te3 nanoflakes and high-σ MWCNTs that could provide good inter-particle connectivity, to significantly enhance the TE performance of PEDOT:PSS. Rigorous flexing and fatigue tests also confirmed the excellent mechanical robustness and stability of these AJ-printed MWCNTs-based TE nanocomposites. The added MWCNTs have led to not only higher σ, but they also have improved the mechanical flexibility and fatigue robustness of the resulting nanocomposites. Since the ZT and PF of TE materials often have a strong dependence on temperature, a single TE material spanning a given temperature range is unlikely to have an optimal ZT or PF across the entire range, leading to the inefficient TEG performance. The temperature-dependent TE properties of AJ-printed TE nanocomposites were therefore studied as a function of the loading fraction, with a view to enhancing the overall TE performance of a TEG by varying its composition accordingly across a given temperature range. For the first time, compositionally graded thermoelectric composites (CG-TECs) have been developed and shown to improve TE performance over TEGs having a single composition across the same temperature range. The composition of the TE nanocomposite was systematically tuned along the length of the TEG in order to optimise the PF along the temperature gradient between which it operates. Lastly, the AJP technique was used to fabricate free-standing and stretchable TE structures, by printing serpentine patterns of the TE ink onto a sacrificial substrate that was subsequently removed. The TE performance and stretchability under different imposed mechanical conditions were evaluated, including testing for the reliability of prolonged stretching cycles. The CG-TEC concept was also incorporated into the stretchable structure to achieve further improvement of TE performance.China Scholarship Council and Cambridge Commonwealth, European and International Trus