Doctor of Philosophy (PhD) / 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.

One of the most devastating effects of tetraplegia is the inability to grasp and manipulate everyday objects necessary to living an independent life. Currently surgery is widely accepted as the solution to improve hand functionality. However, surgery becomes difficult when the user has paralysed wrists as is the case with C5 tetraplegia. The aim of this research was to develop a solution which provided controlled wrist flexion and extension which, when combined with surgery, achieves a 'key pinch' grip. This particular grip is critically important for people with C5 tetraplegia as it is used for countless grasping activities, necessary on a day-to-day basis. A systematic design process was used to evolve the solution to provide controlled wrist flexion and extension. Concept brainstorming identified four alternative solutions which were evaluated to find the preferred concept. The chosen solution was called the Self Powered Wrist Extension Orthosis, more commonly referred to as the 'orthosis'. This concept contained a shoulder harness which provided both energy and control to the wrist harness, which in turn changed the wrist position. The orthosis was developed with the use of a mathematical model which theoretically predicted the functional performance by comparing the required force needed to move the wrist harness to the achievable force supplied by the user's shoulders. Using these parameters, the orthosis was optimized using the matlab Nelder-Mead algorithm which adjusted the wrist harness geometries to maximize the functional performance. A prototype was constructed and tested with the help of two participants who when combined, achieved an average of 18.5° of wrist rotation. The theoretical model however predicted an average range of motion of 28.4°. The discrepancy found between the theoretical and experimental result can be contributed to incorrect assumptions in the theoretical model. This included unaccounted friction and inaccurate modeling of the orthosis dynamics. The feedback from potential users of the orthosis was enthusiastic and encouraging especially towards the simplicity, usability and practicality of the design.

Doctor of Philosophy (PhD) / 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.

This thesis presents a new mechanical design for an exoskeleton actuator to power the sagittal plane motion in the human hip. The device uses a DC motor to drive a Scotch yoke mechanism and series elasticity to take advantage of the cyclic nature of human gait and to reduce the maximum power and control requirements of the exoskeleton. The Scotch yoke actuator creates a position-dependent transmission that varies between 4:1 and infinity, with the peak transmission ratio aligned to the peak torque periods of the human gait cycle. Simulation results show that both the peak and average motor torque can be reduced using this mechanism, potentially allowing a less powerful motor to be used. Furthermore, the motor never needs to reverse direction even when the hip joint does. Preliminary testing shows the exoskeleton can provide an assistive torque and is capable of accurate position tracking at speeds covering the range of human walking. This thesis provides a detailed analysis of how the dynamic nature of human walking can be leveraged, how the hip actuator was designed, and shows how the exoskeleton performed during preliminary human trials.

Musculoskeletal disorders, specifically low back pain, has been well documented andreported by astronauts throughout the space exploration era. Statistics from astronautmemoirs states that 52-68% of astronauts experience moderate to severe lower backpain after prolonged spaceflights. The main cause is atrophy in the paraspinal musclesof the lumbar region. No sufficient countermeasure exists in-flight currently and therehabilitation programs remain ineffective. This thesis presents the first attempt to designand develop a prototype robotic exoskeleton, actuated by pneumatic artificial muscles, asan active countermeasure in-flight where it will be utilised as an equipment for muscularhypertrophy and a supporting device for rehabilitation programs on Earth. It will bemanufactured by additive manufacturing methods for adaptability while remaining lowin weight.A thorough analysis of the spine and lumbar region as a biomechanical system wasmade. Appropriate assumptions was made to simplify the understanding of the complexsystem that is the human spine. The targeted muscles were: multifidus, erector spinaeiliocostalis and erector spinae longissimus. A force analysis of the human torso bendingin the sagittal plane was made, finding that the torques of the torso reaches 244 Nm.The complete exoskeleton design is presented with the parts that will be 3D-printed andthe working principle of the system. Thereafter an extensive model of the exoskeletonis established using Denavit-Hartenberg representation of manipulators as a serial linksystem. The model provides a fundamental understanding of exoskeleton and enablesthe possibility to simulate it accurately. The evaluation protocol for the validation testsis then presented. Active pressure will be tested at 0, 3 and 6 bar and loads of 5 and 11kg will be lifted.Subsequently the assembly, with all the hardware and software selected for the prototypeis demonstrated. Thereafter the results of the evaluation tests are presented followed bya discussion of the results; anomalies, faults and challenges are subjects discussed. Thediscussion concludes that the exoskeleton shows potential for both supporting the motionin a rehabilitation use and enabling muscular hypertrophy in the lumbar region for theresistive tests. Although an extensive heavy-duty evaluation needs to be performed totruly validate the exoskeleton.

The work presented in this paper aims at developing a hydraulic actuation system for an ankle exoskeleton that is able to deliver a peak power of 250 W, with a maximum torque of 90 N.m and maximum speed of 320 deg/s. After justifying the choice of a servo hydraulic actuator (SHA) over an electro hydrostatic actuator (EHA) for the targeted application, some test results of a first functional prototype are presented. The closed-loop unloaded displacement frequency response of the prototype shows a bandwidth ranging from 5 Hz to 8 Hz for displacement amplitudes between +/-5mm and +/- 20mm, thus demonstrating adequate dynamic performance for normal walking speed. Then, a detailed design is proposed as a combination of commercially available components (in particular a miniature servo valve and a membrane accumulator) and a custom aluminium manifold that incorporates the hydraulic cylinder. The actuator design achieves a total weight of 1.0 kg worn at the ankle.

No description available.

Nature develops several materials with remarkable functional properties composed of comparatively simple base substances. Biological materials are often composites, which optime the conformation to their function. On the other hand, synthetic materials are designed a priori, structuring them according to the performance to be achieved. 3D printing manufacturing is the most direct method for specific component production and earmarks the sample with material and geometry designed ad-hoc for a defined purpose, starting from a biomimetic approach to functional structures. The technique has the advantage of being quick, accurate, and with a limited waste of materials. The sample printing occurs through the deposition of material layer by layer. Furthermore, the material is often a composite, which matches the characteristics of components with different geometry and properties, achieving better mechanical and physical performances. This thesis analyses the mechanics of natural and custom-made composites: the spider body and the manufacturing of metallic and non-metallic graphene composites. The spider body is investigated in different sections of the exoskeleton and specifically the fangs. The study involves the mechanical characterization of the single components by the nanoindentation technique, with a special focus on the hardness and Young's modulus. The experimental results were mapped, purposing to present an accurate comparison of the mechanical properties of the spider body. The different stiffness of components is due to the tuning of the same basic material (the cuticle, i.e. mainly composed of chitin) for achieving different mechanical functions, which have improved the animal adaptation to specific evolutive requirements. The synthetic composites, suitable for 3D printing fabrication, are metallic and non-metallic matrices combined with carbon-based fillers. Non-metallic graphene composites are multiscale compounds. Specifically, the material is a blend of acrylonitrile-butadiene-styrene (ABS) matrix and different percentages of micro-carbon fibers (MCF). In the second step, nanoscale filler of carbon nanotubes (CNT) or graphene nanoplatelets (GNP) are added to the base mixture. The production process of composite materials followed a specific protocol for the optimal procedure and the machine parameters, as also foreseen in the literature. This method allowed the control over the percentages of the different materials to be adopted and ensured a homogeneous distribution of fillers in the plastic matrix. Multiscale compounds provide the basic materials for the extrusion of fused filaments, suitable for 3D printing of the samples. The composites were tested in the configuration of compression moulded sheets, as reference tests, and also in the corresponding 3D printed specimens. The addition of the micro-filler inside the ABS matrix caused a notable increment in stiffness and a slight increase in strength, with a significant reduction in deformation at the break. Concurrently, the addition of nanofillers was very effective in improving electrical conductivity compared to pure ABS and micro-composites, even at the lowest filler content. Composites with GNP as a nano-filler had a good impact on the stiffness of the materials, while the electrical conductivity of the composites is favoured by the presence of CNTs. Moreover, the extrusion of the filament and the print of fused filament fabrication led to the creation of voids within the structure, causing a significant loss of mechanical properties and a slight improvement in the electrical conductivity of the multiscale moulded composites. The final aim of this work is the identification of 3D-printed multiscale composites capable of the best matching of mechanical and electrical properties among the different compounds proposed. Since structures with metallic matrix and high mechanical performances are suitable for aerospace and automotive industry applications, metallic graphene composites are studied in the additive manufacturing sector. A comprehensive study of the mechanical and electrical properties of an innovative copper-graphene oxide composite (Cu-GO) was developed in collaboration with Fondazione E. Amaldi, in Rome. An extensive survey campaign on the working conditions was developed, leading to the definition of an optimal protocol of printing parameters for obtaining the samples with the highest density. The composite powders were prepared following two different routes to disperse the nanofiller into Cu matrix and, afterward, were processed by selective laser melting (SLM) technique. Analyses of the morphology, macroscopic and microscopic structure, and degree of oxidation of the printed samples were performed. Samples prepared followed the mechanical mixing procedure showed a better response to the 3D printing process in all tests. The mechanical characterization has instead provided a clear increase in the resistance of the material prepared with the ultrasonicated bath method, despite the greater porosity of specimens. The interesting comparison obtained between samples from different routes highlights the influence of powder preparation and working conditions on the printing results. We hope that the research could be useful to investigate in detail the potential applications suitable for composites in different technological fields and stimulate further comparative analysis.

Exoskeletons are wearable devices that enhance or supplement the user’s natural abilities. They have been demonstrated to be efective in alleviating pain, reducing work related injuries, improving working conditions, and can play a pivotal role in improving recovery times and recovery outcomes. Commercial exoskeletons are expensive, specialised and not easily accessible to the average user. This thesis describes the design and manufacturing processes for the OpenXO, an open-source knee exoskeleton. The focus of the thesis is the design and manufacture of the exoskeleton drive system. It implements a cycloidal drive design. Additionally, a method of designing tapered crossed roller bearings was developed that allows for easy integration into elements of the drive system. The open source aspect is further supported by designing the OpenXO around commercially available additive manufacturing technologies. Rapid prototyping and iterative test-based design methods were used in conjunction with empirical testing and validation of both the design and manufacturing methods. Performance validations were conducted on an unpowered exoskeleton. The tests focus on ease of use and comfort. Validation on the exoskeleton and its components was performed at various stages during the design process. The resulting drive design was signifcantly lighter than commercially available solutions. The stator design implemented allows for press ft accuracy between the rotor and stator while allowing for smooth rotation. The fully assembled exoskeleton was tested by 5 individuals. All participants performed tasks to test the usability the exoskeleton in common day to day activities. The participants managed to perform several tasks with ease. However, the exoskeleton was prone to misalignment in specifc circumstances. Gait analysis on a user wearing the exoskeleton shows that the exoskeleton does infuence gait patterns. However, the user does not experience signifcant impact on their perceived range of motion. These tests do not demonstrate the efectiveness of the exoskeleton when it comes to powered assistance. Further work is needed to test and validate the powered assist functionality of the exoskeleton. / Eksoskeletonit ovat puettavia laitteita, jotka parantavat tai täydentävät käyttäjän luonnollisia kykyjä. Niiden on osoitettu olevan tehokkaita kipujen lievittämisessä, työtapaturmien vähentämisessä, työolosuhteiden parantamisessa ja niillä voi olla keskeinen rooli paranemisaikojen ja toipumistulosten parantamisessa. Kaupalliset eksoskeletonit ovat kalliita, erikoistuneita eivätkä tavallisen käyttäjän helposti saatavilla. Tämä opinnäytetyö kuvaa avoimen lähdekoodin polven eksoskeleton OpenXO:n suunnittelu-ja valmistusprosessit. Erityisesti painopiste on sykloidiseen käyttöjärjestelmään perustuvan ulkopuolisen tukirankajärjestelmän suunnittelussa ja valmistuksessa. Lisäksi kartiorullalaakereiden suunnittelumenetelmä kehitettiin siten, että se mahdollistaa helpon integroinnin käyttöjärjestelmän elementteihin. Avoimen lähdekoodin näkökulmaa tuetaan edelleen suunnittelemalla OpenXO kaupallisesti saatavilla olevien lisäaineiden valmistustekniikoiden ympärille. Nopeaa prototyyppiä ja iteratiivisia testipohjaisia suunnittelumenetelmiä käytettiin sekä suunnittelu-että valmistusmenetelmien empiirisen testauksen ja validoinnin yhteydessä. Suorituskyvyn validointi suoritettiin tehottomalla eksoskeletonilla 5 vapaaehtoisen poolissa. Testit suuntautuivat arjen yleisten toimintojen ympärille ja keskittyivät pääasiassa helppokäyttöisyyteen ja käyttömukavuuteen. Eksoskeleton ja sen komponenttien validointi suoritettiin suunnitteluprosessin eri vaiheissa. Tuloksena saatu käyttörakenne oli huomattavasti kevyempi kuin kaupallisesti saatavilla olevat ratkaisut. Toteutettu staattorin rakenne mahdollisti roottorin ja staattorin välisen puristussovituksen tarkkuuden säilyttäen samalla tasaisen pyörimisen. Osallistujat onnistuivat suorittamaan suurimman osan tehtävistä helposti. Eksoskeleton oli kuitenkin altis kohdistusvirheelle tietyissä olosuhteissa. Eksoskeletonia käyttävän käyttäjän kävelyanalyysi osoittaa, että ulkoinen luuranko vaikuttaa kävelykuvioihin, mutta käyttäjä ei koe merkittävää vaikutusta havaittuun liikerataan. Siitä huolimatta tarvitaan lisätyötä eksoskeletonin tehollisen aputoiminnon testaamiseksi ja validoimiseksi. / <p>Presentation conducted online via the Zoom video conferencing platform.</p>

No description available.