Dissertations / Theses on the topic 'Lower-limb Prostheses'

Sports technology can be any product or system used to facilitate, train or influence an athlete’s performance. The role of prostheses used for disability sport was initially to help facilitate exercise and then ultimately, competition. In able-bodied sport, controversy has occasionally been caused through the adoption or introduction of sports technology. However, scant attention has been paid to sport with a disability with respect to such concerns. This research project provides a novel contribution to knowledge by investigating the use of lower-limb running prostheses in competition by trans-tibial amputees. A novel study using a mixed method approach has investigated the nature, use and assessment of lower-limb running prostheses. It has proposed that the unchecked introduction of such technology has affected the sport negatively. From this, the study conducted a stakeholder assessment of the sport and provided a proposed series of guidelines for lower-limb prostheses technology inclusion. Finally, the recommendation was made that a proactive approach to such technologies’ inclusion in the future should be implemented. These guidelines were further developed by assessing symmetrical and nonsymmetrical lower-limb function and proposed that single and double lowerlimb amputees should be separated in competition in the future. To this end, it was proposed that lower-limb symmetry, stiffness and energy return were important means of monitoring prosthesis performance. Ultimately, a dynamic technique which assesses these qualities was proposed as an assessment strategy for further development in the future.

As is well known, users can make significant contributions to innovations, including innovating themselves. However, much work on user innovation has focussed on developed countries. The question remains whether and how users innovate in a developing country setting. Bodies of literature that explicitly consider innovations in such settings emphasise the influence of limitations. This thesis therefore investigates how limitations shape the creation and sharing of innovations by users. This issue is analysed for medical technologies, because these can have different user groups, including patients, who have been little focussed on, even in developed countries. In this setting, a focus on innovation as defined relatively inclusively is most suitable, and therefore the term 'changes' is often used rather than 'innovations' to express this inclusiveness. By comparing the changes made to the same kind of technology by different groups of users in different settings with different limitations, the influence of these limitations can be analysed. Therefore, data were collected on changes made by patients as well as orthopaedic technicians to lower limb prostheses in two orthopaedic centres in Malawi. First, observations were conducted of the production process for prostheses, followed by semi-structured interviews with orthopaedic technicians and patients, and with additional experts to understand the broader context. It was found that patients and orthopaedic technicians did make many changes. Three kinds of limitations were identified, that influence these changes by users. Like users in developed countries, patients and orthopaedic technicians make these changes to fulfil their needs because available products and services are not satisfactory. Limitations both restrict what products and services are available to users, and also influence the characteristics of the creation and sharing of changes by users. Many users reported on efforts to share their changes with others despite the limitations, often due to a sense of professional collegiality and solidarity. In summary, limitations help to explain how changes by users occur in developing countries, but also how any accumulation of such changes users make is restricted. Improving this situation could help less developed countries in making better use of any user innovations that do occur, and thus contribute to their development more generally.

Background: Cambodia has one of the highest percentages of persons living with disability in the world. Disabled people often encounter stigma in the community, and they do not have the same access to a range of services as the rest of the population. A prosthetic device can enable a disabled person and help them to become more active and participating.   Aim: The aim of this study was to investigate the perception of individuals who have received lower limb prosthesis from Exceed regarding factors that affect their level of activity and participation.  Method: The study is based on recorded qualitative interviews with semi-structured questions. 10 participants between the age of 22-68 who had a prosthesis were included in the study. An inductive content analysis was performed on the data.   Results:The study yielded two main categories which affected the participants activity and participation; Prosthetic limb and a Psychosocial environment. Conclusion: This study gives a deeper understanding of facilitators and barriers affecting activity and participation for individuals with a prosthesis. The results of this study highlight the complexity of the issue and the importance of both the prosthetic device and psychosocial environment. The study gives an insight into factor contributing to different levels of activity and participation and it can help to improve the outcome for prosthetic users.<br>Bakgrund: Kambodja är ett av de länder i världen med störst andel personer med funktionshinder. De stöter ofta påstigma och har inte samma tillgång till en del av de tjänster som resten av befolkningen. En protes kan göra det möjligt för en person med funktionsnedsättning att övervinna svårigheter och att bli mer aktiv och deltagande. Syfte: Syftet med denna studie var att undersöka hur protesanvändare som mottagit sin protes från Exceed uppfattar sin aktivitet och delaktighet och vilka faktorer de anser påverkar detta.    Metod: Inspelade kvalitativa intervjuer med semi-strukturerade frågor användes i studien. 10 deltagare i åldrarna 22–68 deltog i studien. En induktiv content-analys användes för att bearbeta den insamlade datan.    Resultat:Studien resulterade i två huvudkategorier; Protes och Psykosocial miljö, som enligt deltagarna påverkade deras aktivitet och delaktighet Slutsats: Denna studie ger en djupare förståelse för vad som underlättar och hindrar protesanvändare att vara aktiva och delaktiga i vardagen. Studien lyfter också fram ämnets komplexitet där protesen spelar en viktig roll men där även den psykosociala miljön har stor betydelse. Resultatet av denna studie kan hjälpa till att förstå de bakomliggande orsakerna till olika nivåer av aktivitet och deltagande och hjälpa till att förbättra situationen för protesanvändare.

Background: Kiribati has one of the highest rates of diabetes in the world. A major consequence of diabetes is amputation which creates a demand for prosthetic and orthotic services. It is well established that people with amputations who do not have access to a prosthesis experience difficulties with their mobility and participation in society. Aim: To describe activity and participation at home and in the community for individuals who have received a lower limb prosthesis in Kiribati. Method: This study is based on qualitative interviews using a semi-structured approach with seven participants from Kiribati who have been fitted with lower-limb prostheses. Recorded interviews were performed. Results: The study yielded two main categories which led to the participants becoming more independent: the effect of mobility and the importance of relationships. Conclusion: Activity and participation increased in individuals who use a prosthesis as a result of diabetes type 2, compared to those who do not use a prosthesis. Prosthetic use contributes to increased mobility, which affects activity and participation, in turn leading to greater satisfaction in life. Caution should be taken with regard to these conclusions because the gender distribution did not meet the requirements for variation, making it difficult to generalize the results to the population.<br>Bakgrund: Kiribati har en av den högsta prevalensen av diabetes i världen. En stor konsekvens av diabetes är amputation vilket leder till behov av protes- och ortos service. Svårigheter med mobilitet och delaktighet i samhället har visats för personer som är amputerade men inte har tillgång till protes. Syfte: Beskriva aktivitet och delaktighet i hemmet och i samhället för individer som har fått en protes till nedre extremiteten.  Metod: Denna studie är baserad på kvalitativa intervjuer och använder ett semi-strukturerad metod. Sju deltagare från Kiribati med nedre extremitets protes deltog. Inspelade intervjuer genomfördes. Resultat: Studien resulterade i två huvudkategorier, effekten av mobilitet och vikten av relationer. Mobilitet möjliggjorde aktivitet och delaktighet vilket ledde till att deltagarna blev mer självständiga. Nära relationer och hjälp från familjen visade sig viktig efter tillgång till protes. Slutsats: Aktivitet och delaktighet ökade hos individer som till följd av diabetes typ 2 använder sig av protes, i jämförelse med dem som inte använder protes. Protesanvändning bidrar till en ökad mobilitet som påverkar aktivitet och delaktighet vilket leder till högre tillfredställelse i livet. Dessa slutsatser skall dock tas med aktsamhet med anledning av att könsfördelningen inte mötte upp kraven på variation, vilket gör det svårt att generalisera resultatet till populationen.

The introduction of computer-aided tools into the product development process allows improving the quality of the product, evaluating different variants of the same product in a faster way and reducing time and costs. They can play a meaningful role also in designing custom-fit products (especially, those characterized by a tight interaction with the human body), increasing the comfort and improving people’s quality of life. This thesis concerns a specific custom-fit product, the lower limb prosthesis. It is part of a research project that aims at developing a new design platform centred on the digital model of the patient and his/her characteristics. The platform, named Prosthesis Virtual Laboratory (PVL), is being developed by the V&K Research Group (University of Bergamo) and integrates ICT tools and product-process knowledge. It provides two environments: one for prosthesis design (named Prosthesis Modelling Lab), both transfemoral and transtibial, and one for the prosthesis testing (named Virtual Testing Lab). The main objective has been to embed within the Virtual Testing Environment numerical simulation tools to analyse the interaction between the socket and the residual limb under different loading conditions, allowing the prosthetist to automatically run the simulation and optimize socket shape. Simulation tools, such as Finite Element Analysis (FEA), permit to predict the pressures at the interface socket-residual limb, evaluate the comfort of socket and validate the socket design before manufacturing phase. However, the diffusion of simulation tools in orthopaedic laboratories is strongly limited by the high level of competence required to use them. Furthermore, the implementation of the simulation model is time consuming and requires expensive resources, both humans and technological, especially onerous for small orthopaedic labs. To effectively employ the numerical analysis in prosthesis design, the simulation process has been automated and embedded within the virtual design platform. Therefore, in such a context, the specific scientific objectives have been to: • Critically analyse the state of the art with regard to methods and tools to evaluate socket-residual limb interaction. • Identify the key issues to automate the simulation activities. • Define a set of simulation rules and the Finite Element Analysis model. • Implement and integrate within the new design platform the automatic simulation procedure. • Test the integrated design platform with a case study. • Identify future development trends. Research activities have been organized into four main activities as follows. The first activity consisted in an extensive analysis of the last two decades State of the Art on numerical models adopted to study residual lower-limb and prosthetic socket interaction. Starting from literature, the key issues of the simulation process (e.g., geometric models reconstruction, materials characterization, simulation steps, and boundary conditions), the methodologies and procedures have been identified. Particular attention has been also paid to the parameters commonly adopted to evaluate socket comfort. This phase played a fundamental role since it constituted the basis for the implementation of the embedded simulation procedure. It also permitted to highlight that current finite element models are stand-alone and not integrated with prosthetic CAD or Digital Human Modelling (DHM) systems. In the second activity the tools and methods necessary to develop the embedded simulation module have been selected. By using these tools, it was possible to identify the simulation rules and the best practice procedures, which are fundamental to implement an automatic simulation module. Initially, the modelling tools have been considered since they provide the geometric models for the numerical analysis of the socket-residuum interaction and for the virtual gait analysis of the patient’s avatar. Then, particular attention has been paid on the choice of the FE solver, that has been made according to the results of preliminary FE models. They were implemented using two different solvers: Abaqus (commercial) and CalculiX (open-source). The latter has been experimented to verify the possibility to develop a design platform totally independent from commercial tools. However, according to the results, Abaqus has been chosen because it allows managing adequately simulation problems characterized by large deformations and difficult contact conditions, its results are comparable with those found in literature, and its scripting code does not require specific customization. The last considered tool was the Digital Human Modelling system (LifeMOD) since it permits to enhance the accuracy of the numerical analysis. By performing the gait simulation of the patient’s avatar, it provides the directions and the magnitude of forces and moments that act on the socket. The third activity consisted in defining the architecture of the simulation module, implementing the module and the interfaces with the socket CAD tool (namely Socket Modelling Assistant-SMA) to get the geometric models of the involved parts (socket and residual limb) and with the DHM system to acquire forces acting on the socket during patient’s walking. The simulation module has been implemented using the Python language and the integrated environment works as follows. Once the prosthetist has created the 3D socket model, SMA acquires the input for the analysis (e.g., residual limb length, patient’s weight, friction coefficient, material properties), and produces the files required to generate the FE model. Abaqus automatically generates the FE model without any human intervention, solves the analysis and generates the output file containing the pressure values. Results are imported in SMA and visualized with a colour map. SMA evaluates pressure distribution and highlights the areas that should be modified. Geometry modifications are needed in the areas where pressure exceeds the maximum value and are carried out automatically by the system or by the prosthetist using the virtual tools available in SMA. Then, the system re-executes the simulation. Through this iterative process of adjustments, the socket shape is modified and optimized in order to eliminate undercuts, minimize weight and, especially, distribute loads in the appropriate way so that they can be tolerated for the longest period of time. The fourth and last activity concerned the test and validation of the simulation module integrated within the new design platform, by considering a transfemoral patient. The new virtual process and the key issues of the simulation procedure have been tested starting from the patient’s data acquisition to the release of the socket using also data coming from the gait simulation with the DHM system. The geometric model of the residual limb has been reconstructed from MRI images and the socket has been modelled using SMA. Through an iterative process, the socket shape has been optimized until the pressure distribution on the residuum was consistent. Preliminary activity concerning the FE model validation has been performed comparing the pressure distribution experimentally acquired with pressure transducers over the residuum with the simulation results. To accomplish this task, the geometric model of the real socket has been acquired using reverse engineering techniques. Two numerical simulations have been implemented, they differ for the residuum geometric models adopted: from MRI and from 3D scanning. Preliminary results have been considered positive but improvements are necessary. As an example, some geometric inconsistencies, occurred during the acquisition of the geometric model of the residual limb, have reduced the accuracy of the final results. To complete the evaluation of the simulation model, a new residuum geometric model is needed and a refinement of the material model characterization is desirable. To conclude, the simulation module embedded within Virtual Testing Laboratory has improved the prosthesis development process with the goal of assessing and validating the socket shape under different load conditions (static or dynamic) before the manufacturing phase. The testing phase of the new procedure has demonstrated the feasibility of the virtual approach for lower limb prosthesis design. The tests carried out permitted to highlight necessary improvements and future developments, such as the definition of a protocol to acquire the residual limb through MRI and 3D scan, refinement of the FE model (e.g., non-linear viscoelastic behaviour for soft tissues, friction coefficients), parallel computing to improve simulation performances, open-source solvers to implement a design platform totally independent from commercial systems, and a massive test campaign involving transtibial and transfemoral patients to fully validate the FE model and the design platform.<br>L’introduzione di strumenti informatizzati nel processo di sviluppo del prodotto permette di migliorarne la qualità, nonché di valutare diverse varianti del prodotto stesso in modo più veloce, riducendo in tal modo il tempo ed i costi relativi alla progettazione. Per queste motivazioni, tali strumenti possono giocare un ruolo rilevante anche nella realizzazione di prodotti personalizzati (specialmente quelli caratterizzati da una stretta interazione con il corpo umano), aumentandone il comfort e migliorando la qualità di vita delle persone. Il presente lavoro di tesi si concentra nello specifico sull’applicazione di tali strumenti informatizzati nella creazione di protesi per arti inferiori, inserendosi in un progetto di ricerca che ha come obiettivo quello di sviluppare una nuova piattaforma di progettazione centrata sul modello digitale del paziente e sulle sue caratteristiche. La piattaforma, chiamata Prosthesis Virtual Laboratory (PVL), è stata sviluppata dal gruppo di ricerca V&K dell’Università degli Studi di Bergamo nell’ottica di integrare gli strumenti informatici con la conoscenza del prodotto e del processo. La piattaforma è strutturata in modo da offrire due ambienti di lavoro: uno dedicato alla progettazione della protesi (chiamato Prosthesis Modelling Lab), sia transfemorale che transtibiale, e l’altro destinato alla fase di verifica della stessa (chiamato Virtual Testing Lab). L’obiettivo principale del lavoro di tesi è stato quello di integrare, all’interno dell’ambiente virtuale di verifica, gli strumenti di simulazione numerica che consentono di analizzare l’interazione tra l’invaso e l’arto residuo sotto diverse condizioni di carico, permettendo al tecnico protesico di effettuare la simulazione in automatico e di ottimizzare la forma dell’invaso. Gli strumenti di simulazione, come l’analisi agli elementi finiti (FEA), permettono di predire la pressione all’interfaccia tra invaso e moncone, di valutare il comfort dell’invaso e di validare la progettazione dello stesso prima della fase di manifattura. Tuttavia, la diffusione degli strumenti di simulazione nei laboratori ortopedici è fortemente limitata dall’elevato livello di competenze richieste per ottenere risultati significativi. Inoltre, l’implementazione di un modello di simulazione numerica richiede tempo e costose risorse, sia umane che tecnologiche, particolarmente onerose per i piccoli laboratori ortopedici. Affinché l’analisi numerica sia utilizzata nella progettazione delle protesi, è necessario che il processo di simulazione sia automatico ed integrato all’interno di una piattaforma virtuale di progettazione. In questo contesto, gli obiettivi scientifici specifici sono stati: • Analizzare criticamente lo stato dell'arte riguardante i metodi e gli strumenti per valutare l'interazione tra invaso ed arto residuo. • Identificare le questioni chiave per automatizzare le attività di simulazione. • Definire un insieme di regole di simulazione ed il modello per l’analisi ad elementi finiti. • Implementare ed integrare nella nuova piattaforma di progettazione la procedura di simulazione automatica. • Verificare la piattaforma di progettazione integrata con un caso studio. • Identificare le tendenze di sviluppo futuro. Le attività di ricerca sono state organizzate in quattro attività principali, come di seguito presentato nello specifico. La prima attività è consistita in un'analisi approfondita dello stato dell’arte negli ultimi due decenni relativamente ai modelli numerici adottati per studiare l’interazione tra invaso ed arto residuo. Partendo dalla letteratura, sono stati individuati i temi chiave del processo di simulazione (ad esempio la ricostruzione dei modelli geometrici, la caratterizzazione dei materiali, le fasi di simulazione e le condizioni al contorno), nonché le metodologie e le procedure di simulazione. Particolare attenzione è stata posta anche ai parametri comunemente adottati per valutare il comfort dell’invaso. Questa fase ha giocato un ruolo fondamentale in quanto costituisce la base per l’implementazione della procedura di simulazione integrata. Ha permesso altresì di evidenziare come gli attuali modelli agli elementi finiti siano indipendenti e non integrati con i sistemi CAD per protesi o di Digital Human Modelling (DHM). La seconda attività ha avuto come focus la selezione degli strumenti e dei metodi necessari allo sviluppo del modulo di simulazione, per mezzo dei quali è stato possibile identificare le regole di simulazione e le procedure di buona prassi, fondamentali per l’implementazione di un modulo di simulazione automatica. Inizialmente, gli strumenti di modellazione sono stati presi in considerazione in quanto forniscono i modelli geometrici sia per l’analisi numerica dell’interazione tra invaso ed arto residuo che per l’analisi della camminata virtuale dell’avatar del paziente. In seguito, particolare attenzione è stata posta sulla scelta del solutore a elementi finiti, che è stata fatta in accordo con i risultati ottenuti dai modelli preliminari implementati utilizzando due diversi solutori: Abaqus (commerciale) e CalculiX (open-souce). Quest’ultimo è stato impiegato per verificare la possibilità di sviluppare una piattaforma di progettazione totalmente indipendente dagli strumenti commerciali. Tuttavia, in base ai risultati ottenuti, la scelta si è indirizzata verso Abaqus, in quanto permette di gestire in modo adeguato i problemi di simulazione caratterizzati da grandi deformazioni e da difficili condizioni di contatto. L’utilizzo di questo solutore consente di ottenere risultati paragonabili a quelli presenti in letteratura ed inoltre il suo codice di script non richiede specifiche personalizzazioni. L’ultimo strumento utilizzato è stato il sistema DHM (Digital Human Modelling ) che permette di aumentare la precisione dell’analisi numerica. Attraverso l’analisi della camminata virtuale dell’avatar del paziente, questo strumento è in grado di fornire le direzioni e le intensità delle forze e delle coppie che agiscono sull’invaso. La terza attività ha riguardato la definizione dell’architettura del modulo di simulazione, l’implementazione del modulo stesso e del suo interfacciamento prima con lo strumento CAD per l’invaso (chiamato Socket Modelling Assistant - SMA), allo scopo di ottenere i modelli geometrici delle parti coinvolte (invaso ed arto residuo), ed in seguito con il sistema DHM, per acquisire le forze che agiscono sull’invaso durante la deambulazione del paziente. Il modulo di simulazione è stato implementato utilizzando il linguaggio Python e l’ambiente integrato prevede diverse fasi di sviluppo, come di seguito approfondito. Una volta che il tecnico protesico ha creato il modello 3D dell’invaso, lo SMA acquisisce gli input per l’analisi (come la lunghezza dell’arto residuo, il peso del paziente, il coefficiente di attrito, le proprietà dei materiali) e rilascia i file richiesti per generare il modello agli elementi finiti. Abaqus genera automaticamente il modello di simulazione senza che vi sia alcun intervento umano, risolve l’analisi e genera il file di output contenente i valori di pressione. I risultati sono importati nello SMA e visualizzati con una mappa di colore. La modifica della geometria dell’invaso, necessaria nelle aree in cui la pressione eccede i valori massimi, è eseguita in automatico dal sistema o dal tecnico protesico tramite gli strumenti virtuali presenti nello SMA. Il sistema, quindi, riesegue la simulazione. Attraverso questo processo iterativo di rettifica, la forma dell’invaso è modificata ed ottimizzata al fine di eliminare i sottosquadri, minimizzare il peso e soprattutto distribuire i carichi in modo appropriato, così che siano tollerabili per lunghi periodi di tempo. La quarta ed ultima attività ha riguardato la sperimentazione e la validazione del modulo di simulazione integrato all’interno della nuova piattaforma di progettazione considerando un paziente transfemorale. Il nuovo processo virtuale e le questioni chiave della procedura di simulazione sono state testate partendo dall’acquisizione dei dati del paziente fino al rilascio dell’invaso definitivo, utilizzando anche i dati provenenti dalla simulazione della camminata con il sistema DHM. Il modello geometrico dell’arto residuo è stato ricostruito partendo dalle immagini MRI e l’invaso è stato modellato utilizzando lo SMA. Attraverso un processo iterativo, la forma dell’invaso è stata ottimizzata fino ad avere una distribuzione appropriata della pressione sul moncone. L’attività preliminare riguardante la validazione del modello agli elementi finiti è stata eseguita comparando la distribuzione delle pressioni acquisite sperimentalmente sul moncone con i risultati della simulazione. Per realizzare questo compito, il modello geometrico dell’invaso reale è stato acquisito utilizzando tecniche di reverse engineering. Sono state implementate due diverse simulazioni numeriche che differiscono per il modello geometrico del moncone adottato: attraverso MRI nel primo caso, da scansione 3D nel secondo. I risultati preliminari possono considerarsi positivi ma ulteriori sviluppi sono necessari. Ad esempio, alcune incongruenze geometriche che si sono verificate durante l’acquisizione del modello geometrico hanno ridotto la precisione dei risultati finali. Per completare la valutazione del modello di simulazione è quindi necessario utilizzare un nuovo modello geometrico del moncone e sarebbe anche auspicabile raffinare il modello di caratterizzazione del materiale. Concludendo, il modulo di simulazione integrato all’interno del Virtual Testing Laboratory – VTL ha permesso di migliorare il processo di sviluppo della protesi con l’obiettivo di valutare e validare la forma dell’invaso sotto diverse condizioni di carico (statiche o dinamiche), prima della fase di manifattura. La fase di test del nuovo processo ha inoltre dimostrato la fattibilità del nuovo approccio virtuale per la progettazione delle protesi per arti inferiori. I test effettuati hanno indicato quali miglioramenti siano necessari ed i possibili sviluppi futuri, tra cui: la definizione di un protocollo di acquisizione dell’arto residuo attraverso MRI o scansione 3D, il calcolo parallelo per migliorare le prestazioni della simulazione, l’utilizzo di solutori open-source per implementare una piattaforma di progettazione totalmente indipendente dai sistemi commerciali, la realizzazione di una massiccia campagna sperimentale che coinvolga pazienti transtibiali e transfemorali al fine di convalidare pienamente il modello FE e la piattaforma di progettazione.

Misalignment in the lower limb prosthesis can cause great discomfort in the stump- socket interface and disturbance to gait function. In the long run, it could deteriorate the musculoskeletal system. In practice, the assessment still depends heavily on the verbal feedback of an amputee and experiences of a prosthetist. Moreover it is inconsistent amongst the prosthetists. Prosthetic alignment involves the adjustment of the prosthetic components relative to the gait quality. Some methods were proposed, including symmetry index, variation in a step-to-step transition, stability within the zone of integrated balance, matching roll-over shape eROS) to an ideal ROS and etc. It is not clear if the optimum alignment could be achieved. These methods exhibit a few limitations, i.e. limited use of gait variables in a single comparison and non-uniform results when different gait variables are applied. There is a need to provide an objective assessment method that processes high dimensional gait variables and presents them in a simple form. In addition, it could be impractical and expensive clinically to spend excessive time on a patient. An ambulatory gait measurement system could achieve this objective to a certain extent. This research investigates a potential engineering solution that is able to provide an assistive and objective assessment of the lower limb prosthetic alignment that provides optimal gait quality. The effort includes a development of a low-cost ambulatory gait measurement system which could be reliably used during indoor and outdoor trials. Human walking trials using the designed ambulatory system are designed and performed to justify the proposed solution. A novel gait analysis method using Principle Component Analysis and Self-Organizing Feature Map is proposed to process high dimensional gait data into a simple plot and a decision guide. The proposed methodology could help to collect sufficient gait data during indoor and outdoor gaits and could provide an objective gait assessment during the application of lower limb prosthetic alignments.

Le socket prothétique (dit aussi emboiture prothétique), élément d'interface essentiel entre le moignon du patient et le dispositif prothétique, est le plus souvent le lieu où se définit le degré de réussite prothétique. C'est la partie la plus critique de la prothèse, personnalisée pour s'adapter au membre résiduel unique de l'amputé. Sans une forme et un ajustement approprié du socket, la prothèse devient inconfortable, voire inutilisable, et provoque des douleurs et des problèmes de peau. La production prothétique actuelle manque encore de normes numériques universelles pour concevoir un socket. La pratique actuelle est coûteuse et repose sur les raffinements manuels du technicien orthopédiste, et la qualité de l'ajustement est strictement corrélée à ses compétences ainsi qu'aux retours subjectifs du patient lors des phases d’essai de la prothèse fabriquée. La thèse vise à mener une analyse approfondie d'une conception optimale de l'emboîture prothétique en étudiant un processus alternatif de conception assistée par ordinateur. Ce processus est entièrement basé sur le modèle virtuel du membre résiduel du patient et repose sur le calcul de l’interaction emboîture-moignon. Un calcul rapide est favorable dans ce cas, c'est pourquoi nous proposons d'utiliser le système Mass-Spring (MSS) au lieu de la méthode FE largement utilisée pour modéliser les tissus mous du membre résiduel. Une nouvelle configuration du modèle MSS est proposée pour respecter la propriété de non compressibilité des tissus mous en ajoutant des « ressorts correctifs » non linéaires. Le modèle numérique doit être généré à partir du modèle scanné du moignon. À cette fin, nous proposons un schéma de fusion de quatre capteurs de profondeur à bas coût pour un scan rapide et économique avec des techniques de réduction des erreurs. Enfin, le membre résiduel virtuel est utilisé dans la phase de conception du socket. Une méthode de conception paramétrique est proposée et étudiée. Le problème de conception est transformé en problème de satisfaction des contraintes dérivées du calcul inverse de l'interaction socket-moignon. L'approche inverse a été choisie pour éliminer le besoin d'une formulation de contact coûteuse. Ce fait conduit à des calculs rapides, et par conséquent, permet de fournir des retours numériques en temps réel pendant le processus de conception. Le système a été implémenté pas programmation C++ avec une interface graphique où les retours numériques sont donnés sous forme d’une carte de radar. La validation a été faite en comparant les résultats de notre système avec la sortie des simulations FE. Le système a été implémenté avec une interface graphique conviviale et virtuellement testé et validé numériquement. Ce système réduit les limites des pratiques actuelles. Cependant, de nombreux travaux sont encore en cours pour affiner et développer le système et le valider par des expériences cliniques<br>The prosthetic socket, an essential interface element between the patient's stump and prosthetic device, is most often the place where the degree of prosthetic success is defined. It is the most critical part of the prosthesis, customized to fit with the unique residual limb of the amputee. Without a proper socket shape and fit, the prosthesis becomes uncomfortable, or even unusable, and causes pain and skin issues. The state-of-the-art prosthetic production is still missing universal numerical standards to design a socket. The current practice is expensive and relies on the manual refinements of the orthopedic technician, and the fit quality strictly correlates with his skills as well as the subjective feedback of the patient. The thesis aims to conduct a deep analysis of an optimal design of the prosthetic socket by studying and developing an alternative computer-aided design process. This process is fully based on the virtual model of the patient’s residual limb and relies on the calculation of the socket-stump interaction. A fast calculation is favorable in this case, that’s why we propose to use the Mass-Spring System (MSS) instead of the widely used FE method to model the soft tissues of the residual limb. A new configuration of the MSS model is proposed to respect the non-compressibility property of the soft tissues by adding non-linear “Corrective Springs”. The numeric model is to be generated from the scanned model of the stump. For this purpose, we propose a fusion scheme of four RGB-Depth sensors for a rapid and low-cost scan with error reduction techniques. Finally, the virtual residual limb is used in the socket designing phase. A parametric design method is proposed and investigated. The design problem is transformed into a constraint-satisfaction-problem whose constraints are derived from the inverse calculation of the stump-socket interaction. The inverse approach has been chosen to eliminate the need for expensive contact formulation. This fact leads to rapid calculations, and consequently, allows to provide real-time numerical feedback during the designing process. The validation was done by comparing the results of our system with the output of FE simulations. The system has been implemented with a user-friendly graphical interface and virtually tested and numerically validated. This system reduces the limitations of the current practices. However, a lot of works is still ahead to refine and develop the system and validate it with clinical experiments

Alignment of the above-knee prostheses is one of the important factors affecting the success of patient/prosthesis matching. It has been found that the prosthetist and the patient can accept a number of alignments which produce different intersegmental loads and it has been suggested that it is possible to obtain an 'optimal' alignment satisfying certain criteria. In order to enhance the efficiency of the alignment procedure, it is necessary to understand how alignment affects the amputee's gait and the patient compensations for changes in the alignment. Biomechanical gait tests on above-knee amputees were conducted in which the alignment of the prosthesis was changed systematically. The Strathclyde television-computer system was used to record the kinematic data of the amputee, and the ground reactions were measured by two Kistler forceplates. An 8-segment biomechanical model of the above-knee amputee was developed and implemented by a suit of FORTRAN computer programs to analyze and present 3-D kinematic and kinetic data obtained. The effects of alignment changes on the above-knee amputees' gait were studied in terms of the temporal-distance parameters, angular displacements of the lower limbs and the trunk, ground reactions and intersegmental moments. It was found that the angular displacement at the hip joint on the prosthetic side showed compensatory actions of the amputee for the alignment changes. The ground reaction force was sensitive to alignment changes, and in particular, the changes in the characteristics of the fore-aft ground force could be related to the alignment changes. The antero-posterior intersegmental moments about the prosthetic ankle and knee joints were evidently influenced by alignment.

2016 - 2017<br>Hip and knee articulations are the main joints in human body and they have the duty of sustaining heavy loads. This task is normally well performed by a healthy joint but, in some cases, the occurrence of diseases can affect the functionality of the joint: when ambulation is limited, surgery is required. Even if the orthoprosthesis is one of the most effective and successful surgical procedure in the modern medicine, around the 10% of the implanted devices will fail and so require a second surgery. The revision operation is a difficult procedure which needs a long scheduling prior to surgery. Currently, hip and knee joint prostheses are analysed and subjected to simulation tests before receiving the required approval for clinical use. These tests are performed with the aim of establish the behaviour of the prosthesis, assess the wear rate of the components and the surface finishing. However, wear tests on a simulator are long and expensive due to the large number of cycles at low frequency that must be executed. The idea was to move toward an in-silico wear assessment. In order to define which are the most influencing parameters on the tribology of the implants it was investigated the Metal Transfer. It is a migration phenomenon of metal particles found on femoral heads and on acetabular cups of retrieved ceramic hip prostheses, which implies an important alteration of the bearing surface. The presence of transferred metal on ceramic heads changes the surface properties and thus affects lubrication, friction and wear. They were studied 35 ceramics femoral heads of different materials, including zirconia, Biolox® Delta, Biolox® and Biolox® Forte. Differences in surface characteristic appear, as an evidence of the phenomenon, between the affected and unaffected areas... [edited by Author]<br>XVI n.s. (XXX ciclo)

>Magister Scientiae - MSc<br>Persons with lower limb amputations (LLA) experience different challenges in the community. These challenges include the physical, psychological and social function of an individual. Little is known in Malawi on what persons with lower limb amputations go through in the communities where they live. Therefore, the study aimed at exploring and determining community experiences of persons with LLA in Malawi. The study sought to address the following objectives: 1) To determine the functional and psychological status of persons with LLA in the community; 2) To explore and describe experiences on social participation of persons with LLA in the community; 3). To explore experiences on community re-integration following LLA. A mixed method approach was applied where quantitative and qualitative data were collected simultaneously to provide a more holistic overview of the experiences of persons with LLA at one point in time. The study setting was Queen Elizabeth Central Hospital (QECH) and Kamuzu Central Hospitals (KCH) (500 miles), located in Malawi. A sample of 180 participants was recruited to participate in the study. Three self-administered questionnaires (socio-demographic questionnaire, OPUS module of lower extremity functional status, and a Beck’s depression inventory scale) and a semi-structured interview guide were used for data collection. Thematic data analysis was used to analyze qualitative data, while quantitative data was analyzed using descriptive and inferential statistics. Ethical clearance was obtained from the University of the Western Cape Biomedical Research Ethics Committee (BMREC) and College of Medicine Research Ethics Committee (COMREC). Permission to conduct the study was obtained from KCH (500 miles) and QECH. Privacy andconfidentiality was strictly observed such that data obtained was anonymous. It was kept in a secure place, and electronic data was secured using a password.

Relative motion between residual limb and prosthetic socket is an indication of poor fit. Both the fabrication and fitting processes are highly subjective and a favorable result depends upon the technician's expertise. Although numerous methods exist to measure the relative motion, all have limitations and are not well suited for clinical use. A measurement system using optical sensors has been proposed by students at the Technische Universität Darmstadt and evaluations of a functional model have yielded promising results. In this thesis, the existing functional model is improved and expanded to use an array of sensors. A new microcontroller is selected and incorporated into the system. The software and data communication are optimized for fast, reliable performance and the system is then evaluated on a test rig to determine favorable calibration settings and quantify performance. System frequencies up to 1299 Hz are achieved. It is found that the surface microstructure has a dominant effect over short measurement distances; calibrations performed over longer distances are to be preferred. For the chosen calibration factors, the greatest relative errors over a 40 mm distance are found to be 0.90% ± 0.51% in the X direction and -4.76% ± 1.61% in the Y-direction. A systematic drift is also identified. The final system accommodates up to eight sensors and is controlled from a feature-rich MATLAB GUI.<br>Master of Science

ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada<br>Even after rehabilitation, patients with lower-limb amputation may continue to exhibit suboptimal gait. A wireless telemetry system, featuring force sensors, accelerometers, control electronics and a Bluetooth transmission module was developed to measure plantar pressure information and remotely monitor patient mobility. Plantar pressure characterization studies were performed to determine the optimal sensor placement. Finally, the wireless telemetry system was integrated with a previously developed haptic feedback system in order to allow remote monitoring of patient mobility during haptic system validation trials.

This thesis deals with the current state of development of active lower limb prostheses and focuses mainly on own design of active prostheses. The introduction deals with the anatomy of lower limb and briefly describes the walk cycle. In other chapters are summarized amputation techniques in the lower limb, followed by a description of the allocation of prostheses according to the level of amputation, which were described in earlier chapters. The thesis also deals with the division of prostheses according to the patient's activity level and briefly describes the structural differences in these individual cases. Chapter describing the actual development in the field of active prostheses initiates part dealing with the detailed description of the part of the prosthesis. The following chapters deal with the design and implementation of a prototype of active transfemoral prosthesis. The penultimate chapter deals with the software description of all parts of the prosthesis. This chapter is followed by an evaluation of the achieved results.

This report presents the design and manufacturing process of a bionic signal messagebroker (BSMB), intended to allow communication between implanted electrodes andprosthetic legs designed by Ossur. The BSMB processes and analyses the data intorelevant information to control the bionic device. The intention is to carry out eventdetection in the BSMB, where events in the muscle signal are matched to the events ofthe gait cycle (toe-o, stance, swing).The whole system is designed to detect muscle contraction via sensors implantedin residual muscles and transmit the signals wireless to a control unit that activatesassociated functions of a prosthetic leg. Two users, one transtibial and one transfemoral,underwent surgery in order to get electrodes implantable into their residual leg muscles.They are among the rst users in the world to get this kind of implanted sensors.A prototype of the BSMB was manufactured. The process took more time thanexpected, mainly due to the fact that it was decided to use a ball grid array (BGA)microprocessor in order to save space. That meant more complicated routing and higherstandards for the manufacturing of the board. The results of the event detection indicatethat the data from the implanted electrodes can be used in order to get sucient controlover prosthetic legs. These are positive ndings for users of prosthetic legs and shouldincrease their security and quality of life.It is important to keep in mind when the results of this report are evaluated that allthe testing carried out were only done on one user each.

Tissue elasticity assessment is is used in clinical applications from cancer diagnosis to prosthesis fitting. Elastography, using ultrasound to image tissue elasticity to replace digital palpation, includes methods which measure small volume tissue response to high-frequency acoustic excitation and bulk responses following quasi-static loading. Such techniques are well explored and used clinically; however, the goal of quantitative elasticity estimation remains unfulfilled. Additionally, tissue's elastic nonlinearity prevents either approach from providing elasticity information relevant to low-frequency loading as applied by a prosthesis on the lower-limb residuum during gait. This thesis presents research towards the development of a technique utilising the parametric array to exert an acoustic radiation force over small tissue areas under loading frequencies similar to those of gait. The resulting acoustic field magnitude is shown to depend on the elastic properties of the tissue it is developed within. An approach is presented which provides the foundations for a possible medical device to provide high resolution, low frequency, quantitative tissue elasticity information, to aid the prosthetist during fitting or offer the opportunity for automation.

This master thesis deals with lower-limb prosthesis. The aim of the first part of this work is stress-strain analysis of trans-tibial prosthesis, which is understand without prosthetic socket and the foam prosthetic feet. Analysis is made using finite element method in ANSYS Workbench 12.0 software. For the purpose of setting up the computational model it is necessary to make few partial models. Model of geometry of the prosthesis is made in SolidWorks 2009. Based on the outputs of stress-strain analysis and the results evaluation, the critical component is chosen and this one is evaluated according to limite state for fatigue. The algorithm of evaluation of named component in the state of high cycle fatigue is discussed in the second part of this thesis.

Orientador: Marcelo Augusto Assunção Sanches<br>Resumo: Neste trabalho é apresentado o desenvolvimento de um sistema de alinhamento referenciado de prótese de membro inferior, denominado PASyLL (Prosthesis Alignment System of Lower Limbs). A qualidade do alinhamento e ajuste de próteses de membros inferiores é fundamental no processo de reabilitação, principalmente porque contribui para que não ocorra o abandono do uso da prótese. Atualmente, muitos alinhamentos de próteses ainda são realizados de forma subjetiva, sem auxílio de equipamentos, ou seja, apenas com base na experiência e conhecimento do profissional de saúde. Diante disso, desenvolveu-se o PASyLL, um sistema para auxiliar o profissional da saúde no alinhamento de prótese. Este equipamento mede parâmetros importantes para um alinhamento adequado, fornece ao terapeuta dados objetivos, auxiliando-o na tomada de decisão. Com este sistema é possível medir e realizar ajustes no comprimento, medir a distribuição do peso no membro protetizado e não protetizado, verificar a posição do centro de pressão do paciente (COP), desta forma auxiliar no ajuste médio lateral e anteroposterior. O sistema possui fachos laser na horizontal e vertical, permitindo assim um alinhamento referenciado. O erro percentual na medição do peso foi inferior a 1% e na medida do COP, inferior a 5%.<br>Abstract: In this work the development of a referenced alignment system of lower limb prosthesis, called PASyLL (Prosthesis Alignment System of Lower Limbs), is presented. The quality of the alignment and adjustment of lower limb prostheies is fundamental in the rehabilitation process, mainly because it contributes to the abandonment of prosthesis use. Currently, many prosthesis alignments are still performed subjectively, without the aid of equipment, that is, only based on the experience and knowledge of the health professional. Therefore, the PASyLL, a system to assist the health professional in the prosthesis alignment, was developed. This equipment measures important parameters for proper alignment, provides the therapist with objective data, assisting him in decision making. With this system it is possible to measure and adjust the length, measure the weight distribution in the amputated and not amputated limb, verify the position of the patient pressure center (COP) in this way assist in the lateral lateral and anteroposterior adjustment. The system has horizontal and vertical laser beams, allowing a referenced alignment. The percentage error in weight measurement was less than 1% and in the COP, less than 5%.<br>Mestre

A presente pesquisa teve por objetivo a geração de diretrizes de projeto para o desenvolvimento de Próteses de Membros Inferiores, que atendesse as necessidades funcionais dos usuários que resulte na simplificação do objeto. Para isso, investigou-se o usuário, percebendo suas necessidades físicas e psicológicas, com conhecimento de leis federais existentes para o auxílio a esse público. Também, foram examinados a anatomia humana e os procedimentos cirúrgicos para a amputação de membros inferiores, a fim de compreender sua influência na concepção de uma prótese. Outro enfoque da pesquisa foi o estudo da biomecânica para reconhecer os movimentos realizados por uma pessoa sadia durante a deambulação, observando-se as etapas da sua marcha em comparação à marcha de indivíduos amputados que utilizavam próteses. Ainda foram analisados distintos tipos de próteses de membros inferiores e a tecnologia empregada em cada uma de suas partes: sistema de encaixe ao coto, joelho protético e sistema pé-tornozelo. Esses estudos originaram dados empregados na aplicação da metodologia do Design for X, para avaliar as próteses atuais em seus aspectos e construção, com o objetivo de gerar diretrizes de projeto para a elaboração de próteses simplificadas. Constatou-se que a aplicação do método originou diretrizes de projeto que poderão ser empregados durante o desenvolvimento de projetos de próteses de membros inferiores, visando à redução de custo do produto.<br>This research aims to generate design requirements for the development of Lower Limb Prosthetics that meet the functional needs of users, leading to a simplification of the object. For this, we investigated the users regarding their physical and psychological needs, with full knowledge of the existence of federal laws in order to help people. Human anatomy and surgical procedures for lower limb amputation were also examined in order to understand their influence on the design of a prosthesis. Another focus of the research was the study of biomechanics to recognize the movements performed by a healthy person when walking, observing the steps of their march comparing them with the march of amputees who used prosthesis. For the simplified development of prosthesis different types of prosthetic legs have been examined, technology has been employed in each of its parts such as fitting the stump prosthetic knee and the ankle-foot system. These studies yielded useful data used in the application of the methodology of Design for X to assess current prosthetic aspects and construction, to achieve design requirements for the development of simplified prosthesis. It was found that the application of the method originated design requirements that may be employed during the development of lower limb prosthesis projects, aiming to reduce product cost.

Les personnes amputées de membre inférieur (PAMI) sont très diversifiées. Ils’agit d’une population hétérogène, tant par ses origines que par ses niveaux d’amputation, ses capacités et ses projets de vie. A ces profils variés s’ajoutent une multitude de composants prothétiques ainsi que les différentes combinaisons possibles entre ces composants. Il est également important de prendre en compte les différents environnements auxquels la PAMI est confrontée quotidiennement. La Classification Internationale du Fonctionnement (CIF 2001) a été créée par l’Organisation Mondiale de la Santé et repose sur un modèle multidimensionnel. Elle est constituée de deux grandes parties : le fonctionnement d’une part et les facteurs contextuels d’autre part. Ce modèle est capable de décrire de manière globale les modifications de fonctionnement (handicap) à partir d’un problème de santé quelconque. Ainsi, une grande quantité d’informations peut être obtenues à partir du modèle de la CIF. Néanmoins, il demeure nécessaire de développer de nouveaux outils pour mieux exploiter ce modèle afin de le rendre plus intelligible et utilisable en pratique clinique courante. Pour cela, nous nous proposons d’utiliser l’Extraction de Connaissances à partir des Données (ECD). L’ECD est un processus non trivial d'identification des structures inconnues, valide et potentiellement exploitable dans les bases de données, qui permet de transformer un maximum d’informations en connaissances facilement exploitables. A partir du modèle de la CIF et conjointement avec des méthodes d’ECD, l’objectif de cette thèse est de caractériser un groupe de PAMI expertes en termes de capacités locomotrices. Ce groupe et sa liste d’indicateurs pertinents reposant sur le modèle de la CIF ont été déterminés. Ils servent de référence pour la comparaison d’autres PAMI et peuvent guider la prise en charge de cette population particulière<br>The subjects with a lower-limb amputation (LLA) compose a heterogeneouspopulation, by their amputation origins, by their amputation levels, by their abilities and by their life projects. To these various LLA’s profiles we could add a multitude of prosthetic components and the combination of these components. It is also important to take into account the different environments, which the LAA are confronted daily. The International Classification of Functioning, Disability and Health (ICF 2001) was created by the Word Heath Organization and is based on a multidimensional model. The ICF is constituted by two domains: the functioning on one hand and the contextual factors on the other hand. This comprehensive-global model is able to describe the functioning (disability) from any health problem. However it remains necessary to develop new tools to better use the ICF model making it more intelligible and useful in clinical practice. For this, we proposed to use the Knowledge Discovery in Database (KDD). KDD is a non-trivial process of identification of unknown, valid and potentially-exploitable structures in database. KDD permits to transform a maximum of information in easy-exploitable knowledge. From the ICF model conjoint with KDD methods, the aim of this thesis was to characterize an expert group of LLA in terms of locomotion capacity. This group and its list of relevant indicators, based on the ICF model, were determined. They can be used as a reference to compare with others LLA improving making decision of this particular population

The topic of this master’s thesis is design of human leg prosthesis for children. The thesis concerns own design of transbinal prosthesis for children that meet the basic technical, ergonomical and social requi¬rements and also brings a new look and shape as solution to the main topic. The infant incubator is designed in regard to modern materials and technologies.

This masters´s thesis deals with computational modeling of transtibial lower-limb prosthesis. For assesment of loading character and geometrical configuration, the gait analysis of an amputee, including ground reaction force measurement, strain gauge analysis and motion analysis, was accomplished. Information on geometry was obtained using 3D optical scanning procedure. Material model was gathered using non-destructive mechanical testing and mimicked in a FEA software. For loading conditions the static structure analysys using FEM was accomplished. The critical poins in construction was found. Recognition of agreement about experimental and computational model was accomplished.

The aim of this thesis was to determine the biomechanical adaptations made by active unilateral trans-tibial amputees when they used a prosthesis incorporating a hydraulically-damped, articulating ankle-foot device compared to non-hydraulically attached devices. Kinematic and kinetic data were recorded while participants ambulated over a flat and level surface at their customary walking speeds and at speeds they perceived to be faster and slower using the hydraulic device and their habitual foot. Use of the hydraulic device resulted in increases in self-selected walking speeds with a simultaneous reduction in intact-limb work per meter travelled. Use of the device also attenuated inappropriate fluctuations in the centre-of-pressure trajectory beneath the prosthetic foot and facilitated increased residual-knee loading-response flexion and prosthetic-limb load bearing during stance. These changes occurred despite the hydraulic device absorbing more, and returning less, energy than the participants’ habitual ankle-foot devices. The changes were present across all walking speeds but were greatest at customary walking speeds. The findings suggest that a hydraulic ankle-foot device has mechanical benefits, during overground gait, for active unilateral trans-tibial amputees compared to other attachment methods. The findings also highlight that prosthetic ankle-foot device ‘performance’ can be evaluated using surrogate measures and without modelling an ‘ankle joint’ on the prosthetic limb.

The aim of this thesis was to determine the biomechanical adaptations made by active unilateral trans-tibial amputees when they used a prosthesis incorporating a hydraulically-damped, articulating ankle-foot device compared to non-hydraulically attached devices. Kinematic and kinetic data were recorded while participants ambulated over a flat and level surface at their customary walking speeds and at speeds they perceived to be faster and slower using the hydraulic device and their habitual foot. Use of the hydraulic device resulted in increases in self-selected walking speeds with a simultaneous reduction in intact-limb work per meter travelled. Use of the device also attenuated inappropriate fluctuations in the centre-of-pressure trajectory beneath the prosthetic foot and facilitated increased residual-knee loading-response flexion and prosthetic-limb load bearing during stance. These changes occurred despite the hydraulic device absorbing more, and returning less, energy than the participants’ habitual ankle-foot devices. The changes were present across all walking speeds but were greatest at customary walking speeds. The findings suggest that a hydraulic ankle-foot device has mechanical benefits, during overground gait, for active unilateral trans-tibial amputees compared to other attachment methods. The findings also highlight that prosthetic ankle-foot device ‘performance’ can be evaluated using surrogate measures and without modelling an ‘ankle joint’ on the prosthetic limb.

Preface: The research about product development of a prosthetic socket was conducted by two students from Mälardalen University, department of Innovation, Design, and Technology. Background: The most recent public survey shows that an estimated 5 million people in China are amputees, out of which a significantly large portion are below-elbow amputees. Sockets sold to below-elbow amputees are equipped with only two surface electromyography sensors, has low comfortability, has problems with perspiration, and a high weight. The current standard for socket manufacturing has not changed in decades. Research Questions: The following research questions have determined the direction of the research: (1) What measurable factors contribute to a convenient and ergonomic feature design in prosthetic socket from the end-user’s perspective? (2) How can the weight and functionality be improved to achieve a prosthetic socket more suited to the end-user, with respect to the existing prosthetic socket? (3) Which material and manufacturing method is suitable for producing cost-effective and customized prosthetic sockets? Research Method: The research was guided by the 5th edition of Product Design and Development by Ulrich &amp; Eppinger (2012) where the product development process described in five of the six phases from planning to test and refinement were utilized. The data collection and analysis techniques performed in this research was guided by Research Methods for Students, Academics and Professionals by Williamson &amp; Bow (2002). Interviews were conducted with five different stakeholders to find specifications of requirements and concretize subjectivism of what defines quality and ergonomics. Implementation: Currently, below-elbow amputees order sockets from orthopedic clinics. The socket was identified as a product of Ottobock. Investigations were made to find optimal solutions to the specification of requirements. Results: The development of a socket concept was designed for additive manufacturing using a multi-jet fusion printer. Analysis: This concept had significant improvements to parameters: higher grade of customizability, 30 % reduced weight, 48 % cost reduction, a new production workflow with 93,5 % automation, and a 69 % reduction in manual work hours. Conclusions: The data of the research strongly indicate existing potentials in enhancing socket design techniques and outputs by implementation of additive manufacturing processes. This can prove to be beneficial for achieving more competitive prosthetics and associated services.<br>Förord: Denna forskning om produktutvecklingsprocessen av en armprotes genomfördes av två studenter från Mälardalens universitet, avdelningen för innovation, design och teknik. Bakgrund: Den senaste offentliga undersökningen visar att cirka 5 miljoner människor i Kina är amputerade, varav en betydligt stor del är under-armbågsamputerade. Armproteser som säljs till underarmsamputerade individer är utrustade med endast två yt-elektromyografiska sensorer, har låg komfort, har problem med perspiration och hög vikt. Den nuvarande standarden för armproteser har inte förändrats under årtionden. Forskningsfrågor: Följande forskningsfrågor har bestämt riktningen för forskningen: (1) Vilka mätbara faktorer bidrar till en praktisk och ergonomisk funktionsdesign i underarmsproteser ur slutanvändarens perspektiv? (2) Hur kan vikten och funktionaliteten förbättras för att åstadkomma en underarmsprotes som är bättre anpassad för slutanvändaren med avseende på den befintliga underarmsprotesen? (3) Vilket material och tillverkningsmetod är lämpligt för att producera kostnadseffektiva och anpassade underarmsproteser? Forskningsmetod: Forskningsmetoden styrdes av den femte upplagan av Product Design and Development av Ulrich &amp; Eppinger (2012) där produktutvecklingsprocessen är uppdelad i sex faser. I denna forskning användes de fem första faserna från planering till testning och justering. Tekniker för datainsamling och analys som användes i denna forskning styrdes av Research Methods for Students, Academics and Professionals av Williamson &amp; Bow (2002). Intervjuer genomfördes med fem olika intressenter för att hitta kravspecifikationer och för att konkretisera subjektivitet för vad som definierar kvalitet och ergonomi. Implementering:  Underarmsamputerade individer beställer för närvarande armproteser från ortopediska kliniker. Armprotesen identifierades som en produkt av Ottobock. Undersökningar gjordes för att hitta optimala lösningar för kravspecifikationen. Resultat: Konceptutvecklingen av en armprotes utformades för additiv tillverkning med hjälp av en multi-jet-fusion-skrivare. Analys: Det här konceptet hade betydande förbättringar av parametrar: högre grad av anpassningsbarhet, 30 % minskad vikt, 48 % kostnadsreduktion, ett nytt produktionsflöde med 93,5 % automatisering och en 69 % minskning av manuella arbetstider. Slutsatser: Data från denna forskning indikerar att det finns starkt potential för att förbättra designtekniker och utgångar av underarmsproteser genom implementering av additiva tillverkningsprocesser. Detta kan visa sig vara fördelaktigt för att uppnå mer konkurrenskraftiga proteser och tillhörande tjänster.

This Ph.D thesis refers to a research project that aims at developing an innovative platform to design lower limb prosthesis (both for below and above knee amputation) centered on the virtual model of the amputee and based on a computer-aided and knowledge-guided approach. The attention has been put on the modeling tool of the socket, which is the most critical component of the whole prosthesis. The main aim has been to redesign and develop a new prosthetic CAD tool, named SMA2 (Socket Modelling Assistant2) exploiting a low-cost IT technologies (e.g. hand/finger tracking devices) and making the user’s interaction as much as possible natural and similar to the hand-made manipulation. The research activities have been carried out in six phases as described in the following. First, limits and criticalities of the already available modeling tool (namely SMA) have been identified. To this end, the first version of SMA has been tested with Ortopedia Panini and the orthopedic research group of Salford University in Manchester with real case studies. Main criticalities were related to: (i) automatic reconstruction of the residuum geometric model starting from medical images, (ii) performance of virtual modeling tools to generate the socket shape, and (iii) interaction mainly based on traditional devices (e.g., mouse and keyboard). The second phase lead to the software reengineering of SMA according to the limits identified in the first phase. The software architecture has been re-designed adopting an object-oriented paradigm and its modularity permits to remove or add new features in a very simple way. The new modeling system, i.e. SMA2, has been totally implemented using open source Software Development Kit-SDK (e.g., Visualization ToolKit VTK, OpenCASCADE and Qt SDK) and based on low cost technology. It includes: • A new module to automatically reconstruct the 3D model of the residual limb from MRI images. In addition, a new procedure based on low-cost technology, such as Microsoft Kinect V2 sensor, has been identified to acquire the 3D external shape of the residuum. • An open source software library, named SimplyNURBS, for NURBS modeling and specifically used for the automatic reconstruction of the residuum 3D model from medical images. Even if, SimplyNURBS has been conceived for the prosthetic domain, it can be used to develop NURBS-based modeling tools for a range of applicative domains from health-care to clothing design. • A module for mesh editing to emulate the hand-made operations carried out by orthopedic technicians during traditional socket manufacturing process. In addition several virtual widgets have been implemented to make available virtual tools similar to the real ones used by the prosthetist, such as tape measure and pencil. • A Natural User Interface (NUI) to allow the interaction with the residuum and socket models using hand-tracking and haptic devices. • A module to generate the geometric models for additive manufacturing of the socket. The third phase concerned the study and design of augmented interaction with particular attention to the Natural User Interface (NUI) for the use of hand-tracking and haptic devices into SMA2. The NUI is based on the use of the Leap Motion device. A set of gestures, mainly iconic and suitable for the considered domain, has been identified taking into account ergonomic issues (e.g., arm posture) and ease of use. The modularity of SMA2 permits us to easily generate the software interface for each device for augmented interaction. To this end, a software module, named Tracking plug-in, has been developed to automatically generate the source code of software interfaces for managing the interaction with low cost hand-tracking devices (e.g., Leap Motion and Intel Gesture Camera) and replicate/emulate manual operations usually performed to design custom-fit products, such medical devices and garments. Regarding haptic rendering, two different devices have been considered, the Falcon Novint, and a haptic mouse developed in-house. In the fourth phase, additive manufacturing technologies have been investigated, in particular FDM one. 3D printing has been exploited in order to permit the creation of trial sockets in laboratory to evaluate the potentiality of SMA2. Furthermore, research activities have been done to study new ways to design the socket. An innovative way to build the socket has been developed based on multi-material 3D printing. Taking advantage of flexible material and multi-material print possibility, new 3D printers permit to create object with soft and hard parts. In this phase, issues about infill, materials and comfort have been faced and solved considering different compositions of materials to re-design the socket shape. In the fifth phase the implemented solution, integrated within the whole prosthesis design platform, has been tested with a transfemoral amputee. Following activities have been performed: • 3D acquisition of the residuum using MRI and commercial 3D scanning systems (low cost and professional). • Creation of the residual limb and socket geometry. • Multi-material 3D printing of the socket using FDM technology. • Gait analysis of the amputee wearing the socket using a markerless motion capture system. • Acquisition of contact pressure between residual limb and a trial socket by means of Teskan’s F-Socket System. Acquired data have been combined inside an ad-hoc developed application, which permits to simultaneously visualize pressure data on the 3D model of the residual lower limb and the animation of gait analysis. Results and feedback have been possible thanks to this application that permits to find correlation between several phases of the gait cycle and the pressure data at the same time. Reached results have been considered very interested and several tests have been planned in order to try the system in orthopedic laboratories in real cases. The reached results have been very useful to evaluate the quality of SMA2 as a future instruments that can be exploited for orthopedic technicians in order to create real socket for patients. The solution has the potentiality to begin a potential commercial product, which will be able to substitute the classic procedure for socket design. The sixth phase concerned the evolution of SMA2 as a Mixed Reality environment, named Virtual Orthopedic LABoratory (VOLAB). The proposed solution is based on low cost devices and open source libraries (e.g., OpenCL and VTK). In particular, the hardware architecture consists of three Microsoft Kinect v2 for human body tracking, the head mounted display Oculus Rift SDK 2 for 3D environment rendering, and the Leap Motion device for hand/fingers tracking. The software development has been based on the modular structure of SMA2 and dedicated modules have been developed to guarantee the communication among the devices. At present, two preliminary tests have been carried out: the first to verify real-time performance of the virtual environment and the second one to verify the augmented interaction with hands using SMA2 modeling tools. Achieved results are very promising but, highlighted some limitations of this first version of VOLAB and improvements are necessary. For example, the quality of the 3D real world reconstruction, especially as far as concern the residual limb, could be improved by using two HD-RGB cameras together the Oculus Rift. To conclude, the obtained results have been evaluated very interested and encouraging from the technical staff of orthopedic laboratory. SMA2 will made possible an important change of the process to design the socket of lower limb prosthesis, from a traditional hand-made manufacturing process to a totally virtual knowledge-guided process. The proposed solutions and results reached so far can be exploited in other industrial sectors where the final product heavily depends on the human body morphology. In fact, preliminary software development has been done to create a virtual environment for clothing design by starting from the basic modules exploited in SMA2.<br>La presente tesi di dottorato è stata sviluppata nell’ambito di un progetto di ricerca che ha come obiettivo lo sviluppo di un framework innovativo per la progettazione di protesi per arto inferiore (per amputazioni sia transfemorali sia transtibiali) che permetta di gestire l’intero processo in un unico ambiente integrato dove ciascuna attività è supportata in modo diretto dalla conoscenza di dominio specifica. L’attenzione è stata posta sullo sviluppo di un’applicazione per la progettazione dell’invaso, il componente più critico dell’intera protesi. L’obbiettivo principale del lavoro di tesi è stato, quindi, la reingegnerizzazione e lo sviluppo di un nuovo sistema CAD prostetico, denominato SMA2 (Socket Modelling Assistant2, basato sull’impiego di tecnologie innovative a basso costo, quali ad esempio periferiche per il tracciamento di mani e dita, per permettere l’interazione uomo-macchina il più naturale possibile. Le attività di ricerca sono state organizzate in sei fasi principali come segue. Durante la prima fase, i limiti e le criticità della prima versione del sistema di modellazione (denominato SMA) sono stati identificati. A tal fine, SMA è stato testato con il personale tecnicno dell’ortopedia Panini e con i ricercatori del gruppo di ricerca in ortopedia della Salford University di Manchester utilizzando casi di studio reali. Sono state identificate le seguenti criticità a: (i) difficoltà nella ricostruzione del modello 3D dell’arto amputato partendo da immagine mediche, (ii) prestazioni delle modalità di modellazione 3D dell’invaso non adeguate e (iii) interazione con l’ambiente virtuale basata esclusivamente su periferiche classiche come tastiera e mouse e non era possibile emulare le tipiche operazioni di modifica dell’invaso. La seconda fase ha riguardato la riprogettazione del sistema di modellazione SMA in funzione dei limiti identificati nella prima fase. L’architettura software è stata riprogettata seguendo i paradigmi della progettazione orientata agli oggetti e la sua modularità permette di rimuovere o aggiungere nuovi moduli in modo semplice. Il nuovo sistema di modellazione, SMA2, è stato totalmente implementato usando Software Development Kit (SDK) con licenza open-source (in particolare Visualization ToolKit VTK, OpenCASCADE e Qt SDK) e basato su tecnologia a basso costo. Il sistema comprende: • Un nuovo modulo per la ricostruzione automatica dell’arto residuo partendo da immagini MRI. In aggiunta, una nuova procedura basata su tecnologia a basso costo, come Microsoft Kinect v2, è stata identificata ed utilizzata per acquisire il modello 3D dell’arto residuo. • Una libreria software open-souce, denominata SimplyNURBS, per la modellazione di superfici NURBS e specificatamente utilizzata per la ricostruzione automatica dell’arto amputato partendo dalle imamgini MRI. Anche se SimplyNURBS è stata sviluppata nell’ambito della progettazione di protesi per arti inferiori, essa può essere usata all’interno di altre applicazioni, sia in ambito medico sia in ambito industriale per quei prodotti la cui modellazione richiede l’utilizzo di modelli NURBS, quali ad esempio capi di abbigliamento. • Un modulo per la modifica di mesh triangolari per emulare le operationi manuali effettuate dai tecnici ortopedici durante il processo di sviluppo prodotto dell’invaso. Inoltre, sono stati sviluppati strumenti di modellazione virtuali per simulare quelli utilizzati dal tecnico ortopedico, quali ad esempio il metro per misurare l’arto residuo o la matita per evidenziare le zone critiche dell’invaso. • Una Natural User Interface (NUI) che permette di interagire con i modelli dell’arto residuo e dell’invaso attraverso periferiche di hand-tracking. • Un modulo per generare il modello geometrico dell’invaso per la realizzazione dello stesso mediante tecnologie di produzione additive. La terza fase ha riguardato lo studio e la progettazione dell’interazione aumentata con particolare attenzione allo sviluppo di una Natural User Interface per l’uso di periferiche di hand-tracking e di force-feedback. La NUI è basata sull’uso della periferica di hand-tracking Leap Motion. Un insieme di gesti, principalmente iconici e adatti al dominio considerato, sono stati indentificati tenendo in considerazione vincoli ergonomici (per esempio, la postura delle braccia) e la facilità di utilizzo. La modularità di SMA2 ha permesso di generare in modo semplice un’interfaccia software per ogni dispositivo di hand-tracking preso in considerazione. Inoltre, è stato sviluppato un modulo software, denominato Tracking plug-in, che permette di generare in automatico il codice sorgente per la creazione di interfacce per l’interazione con dispositivi di hand-tracking, come ad esempio Leap Motion e Intel Gesture Camera. In questo modo è possibile replicare/emulare le operazioni che vengono eseguite durante la progettazione di prodotti custom-fit, quali protesi e capi di abbigliamento. Per quanto riguarda i dispositivi per l’interazione tattile, sono stati considerati il Novint Falcon e un mouse aptico sviluppato ad hoc. Durante la quarta fase, sono state studiate ed analizzate le tecnologie di Additive Manufacturing, ponendo particolare attenzione alla tecnologia FDM. Tale tecnologia è stata utilizzata per realizzare l’invaso di un paziente progettato con SMA2 e verificarne le potenzialità. Inoltre, sono state condotte attività di ricerca per valutare nuove modalità di progettazione dell’invaso. In particolare, è stata considerata la possibilità di progettare e realizzare l’invaso utilizzando una stampante FDM multi materiale. Sfuttando possibilità di utilizzare materiali flessibili e la stampa di oggetti con materiali diversi, è possibile realizzare un invaso composto da parti flessibili e parti più rigide. A tal fine sono stati presi in considerazione aspetti, quali le modalità di riempimento (infill) durante la stampa 3D, i materiali per la realizzazione delle diverse parti ed il Durante la quinta fase, il sistema implementato, integrato all’interno dell’intera piattaforma per la progettazione di protesi, è stato sperimentato con un paziente con amputazione transfermorale. Sono state svolte le seguenti attività: • Acquisizione dell’arto amputato mediante Risonanza Magnetica e sistemi commerciali di acquisizione 3D (sia a basso coste sia professionali). • Creazione della geometria 3D dell’arto residuo e dell’invaso. • Stampa 3D multi materiale dell’invaso utilizzando la tecnologia FDM. • Analisi della camminata dell’amputato mediante un sistema di acquisizione del movimento. • Acquisizione delle pressioni di contatto tra invaso e arto residuo mediante il sistema Teskan F-Socket System. Mediante un’applicazione sviluppata ad hoc, è stato possibile rimappare sul modello 3D dell’invaso i valori di pressione acquisiti mediante mappe di colore e simultaneamente visualizzare l’animazione della camminata acquisita. Questa applicazione permette di identificare eventuali correlazioni tra le differenti fasi del ciclo della camminata ed i valori di pressione acquisiti. I risultati raggiunti si sono rilevati d’interesse e sono stati pianificati ulteriori test per validare il sistema con altri pazienti. I risultati ottenuti hanno, inoltre permesso di valutare le potenzialità di SMA2 ed il suo impiego presso laboratori ortopedici. La soluzione ha il potenziale per diventare un prodotto commerciale e quindi sostituire la procedura manuale seguita per progettazione dell’invaso. La sesta fase ha riguardato l’evoluzione di SMA2 come ambiente di Mixed Reality. La soluzione proposta, denominata Virtual Othopedic Laboratory (VOLAB), è sempre basata su dispositivi a basso costo e librerie software open source (OpenCL e VTK). In particolare, l’architettura hardware comprende tre Microsoft Kinect v2 per il tracciamento del corpo umano, il sistema di visione 3D Oculus Rift SDK 2 per il rendering dell’ambiente virtuale ed il dispositivo Leap Motion per il tracciamento della mani/dita. Lo sviluppo software è basato sulla struttura modulare di SMA2 e moduli dedicati che sono stati sviluppati per garantire la comunicazione tra i vari dispositivi coinvolti. Attualmente, sono stati svolti due test preliminari: il primo per verificare le prestazioni real-time dell’ambiente virtuale ed il secondo per verificare l’interazione con i dispositivi di hand-tracking durante l’utilizzo degli strumenti di modellazione virtuale messi a disposizione da SMA2. I risultati ottenuti sono molto promettenti, ma sono necessari ulteriori miglioramenti. Per esempio, la qualità della ricostruzione dell’ambiente virtuale, in particolare del modello dell’arto residuo, potrebbe essere migliorata utilizzando due camere HD-RGB in aggiunta all’Oculus Rift. Per concludere, i risultati ottenuti sono stati considerati molto interessanti ed incoraggianti dallo staff tecnico dei laboratori ortopedici. SMA2 renderà possibile un importante cambiamento del modo di progettare un invaso per protesi d’arto inferiore, da un processo tradizionalmente manuale ad un nuovo processo basato su approccio virtuale e l’impiego di strumenti computer-aided. Le soluzioni proposte ed i risultati raggiunti possono essere utilizzati anche in altri settori industriali dove il prodotto finale dipende fortemente dalla morfologia del corpo umano. Infatti, sono stati sviluppati alcuni moduli software per la progettazioni di capi di abbigliamento partendo dai moduli base sviluppati per SMA2.

Human upright locomotion emerged about 6 million years ago. It is achieved by a complex interaction of the biological infrastructure and the neural control. Bones, muscles, tendons, central nervous commands and reflex mechanisms interact to provide robust and efficient bipedal movement patterns like walking or running. Next to these locomotion tasks humans can also perform complex movements like climbing, dancing or jumping. Diseases or traumatic events may cause the loss of parts of the biological infrastructure or the ability to control the lower limbs. Thus an identification of the required framework helps to improve on the artificial lower limb design and the control for bipedal robots, exoskeletons, orthoses or prostheses. A first artificial leg design was reported about 5000 years ago. After losing one leg in a battle an iron leg was fitted to Queen Vishpla to get her back on the battlefield. Since this time major changes in the structure, the material and the functionality led to improved prosthetic restoration of physically disabled. The characteristics of the biological leg structure are imitated by technical components. Using carbon fiber for the design of prosthetic feet made it possible to benefit from the elastic recoil like in the Achilles tendon in stance phase. Dampers in prosthetic knee joints are able to mimic eccentric muscle work during the gait cycle. Clutch-like mechanisms are used to lock the knee during stance. Such a function is comparable to isometric muscle work. Semiactive knee joints allow changes in damping ratio to adapt the mechanical joint properties to the requirements. Using integrated force or inertial sensors, movement tasks can be identified. An adaptation of damping to different walking speeds and conditions, such as walking inclines, declines, or climbing stairs is possible. All these developments permitted that amputees gait got closer to the natural human gait pattern. However, until the end of the 20th century prostheses were not able to reproduce concentric muscle work. External positive energy is required to compensate for energy losses during locomotion. For climbing stairs or walking inclines not only the ankle, but also the knee joint contributes net positive work to lift the body center of mass. To achieve desired joint motion, a power source like a motor would be required that can inject energy to mimic the concentric function of the muscle fascicles. The thesis comprises an analysis of joint requirements, it evaluates the current prosthetic design approaches and develops models on artificial muscles to mimic lower limb biomechanics in walking and running. The developed models are biologically inspired, while motors represent the function of muscle fibers and springs represent the function of the tendons. These systems are optimized for criteria like minimum joint peak power or minimum required energy for the power source (motor). Results demonstrate that elastic elements can highly decrease the actuator requirements. The springs are able to store energy in one phase of the gait cycle and to release it later when high peak power is required. Without the elastic assistance the reproduction of human joint behavior is hardly possible using current motor technology. The optimized interaction of motor and elasticity is evaluated in walking and running, using a prototype of a powered ankle prosthesis (Walk-Run ankle, Springactive). Next to experiments with a nonamputee, where the prosthesis was fitted in parallel to the fixed healthy ankle joint (Bypass), also experiments with a female unilateral transtibial amputee were performed. The optimized model behavior was compared to experimental observations and showed good agreement. Furthrmore, a concept on the improvement of an optimized walking motor pattern was successfully tested. By smoothening the motor curve to the main characteristics (low-pass filter) it was possible to increase the mechanical work output, to improve the system efficiency, and to decrease the electrical energy consumption and the noise. To further improve the prosthetic performance, the push off timing and the causes for prosthesis noise should be analyzed. Weight reductions and psychoacoustic analysis can additionally help to improve on the amputees acceptance. In addition it must be evaluated how training can effect amputees gait patterns when using powered prostheses. To further reduce the power and the energy requirements, an improvement on the powered prosthesis efficiency is recommended. The efficiency can be further increased by using higher efficiency parts and improving the interaction of the prosthesis and the amputee. The human - machine interaction depends on the prosthesis mechanics and the control algorithm. Similar to the human biarticular muscles, couplings from biological to artificial joints may provide additional benefits for the amputee. The muscles from existing proximal joints would be able to transfer energy to the distal artificial joints. Also the inverse of this principle would be possible. A coupling between the hip and the knee (transfemoral amputees) and between the knee and the ankle (transfemoral and transtibial amputees) would be possible. Due to geometrical constraints, the elemental locomotion control might improve. The results of the thesis, on the efficient cooperation of motors and springs, can be used to improve the design and the control of powered lower limb prostheses. Similar technologies can be used to improve on exoskeleton design to assist elderly and subjects with mobility impairments. Elastic exoskeletons may also augment human performance in daily life or workers environments. Next to assisting the human movement, the elastic actuators may advance the gait performance, the gait robustness, and the operation time of bipedal robots. Thus the results of the thesis Powered Lower Limb Prostheses are not limited to the specific field of prosthetics but may also be useful for applications like exoskeletons and legged robots.

Dissertação de mestrado integrado em Engenharia Biomédica<br>The increasing rate of amputations reinforce the need to improve the prostheses currently on the market and develop new solutions, to provide a better quality of life for the amputees. The suspension systems have a fundamental role in adapting to the prosthesis and amputee’s rehabilitation. These systems guarantee a firm attachment between the residual limb and prosthesis. The suspension systems available in the currently market, do not provide the quality of life that the lower limb amputees deserve, since do not ensure the total safety and comfort enough to use the prosthesis in long term. These limitations are associated with the difficulties on donning and doffing the prosthesis. This dissertation proposes a novel approach to solve some of these limitations. The proposed suspension system was obtained following the Design methodology, to understand the amputees’ needs, define the statement-problem, create several alternative solutions, and prototyping and testing the selected solution. The new suspension system is a combination of a guiding and fixation mechanisms, that improves the donning and doffing of prosthesis and, consequently, increases the amputee’s satisfaction. Motion analysis, safety and functional tests were done to evaluate the performance of the prototype and ensure that the proposed solution is viable and follows all the requirements and specifications stablished. Due to some technical issues, it was not possible to test all the functionalities of the prototype of the suspension system. However, the proposed suspension system presented an effective fixation of the serrated pin. Additional tests are still needed to evaluate the proposed system with the intention of being tested on amputees. In short, the new suspension system is a good alternative system to improve the life quality of amputees with lower activity level on the daily basis. With this dissertation, were published abstract for the Regional HELIX'17 conference and a paper for the International Journal of Mechatronics and Applied Mechanics, and a paper for the ICEUBI 2017 conference.

The normal daily human activities include different levels of energy and strength needs, and this applies also for walking such that walking at high speeds needs more stiff muscles compared with walking slowly, and walking during carrying heavy loads or on inclined surfaces needs more energy than during doing the light housekeeping activities. For a healthy individual the human foot has already the ability to change its stiffness and to store and return a part of the elastic energy in a compliant structure of muscle fibres and series elastic elements. In the case of amputations in the lower limbs the amputated limbs are replaced with artificial limbs. A problem appears by this replacement that the new artificial limbs are designed to satisfy some described tasks and any change in these tasks or in the boundary conditions leads to an incompliance and unsatisfactory motion of the amputees. For example, the use of soft foot for walking at high speeds leads to a larger motion of the body centre of mass compared with walking at the preferred walking speed. In order to overcome these problems or reduce their effects, the need arises to design adaptive prostheses that have the ability to change their properties according to the surrounding conditions. This work has the goal to evaluate the usefulness of using adaptive elastic foot prosthesis, through the numerical modelling and simulation of the human gait of an above-knee amputee with an adaptive elastic foot. The body of the amputee is divided into a limited number of rigid bodies (segments) connected together by hinge joints. A two dimensional model of the human body is built from these segments using a commercial multibody simulation program. The initial conditions of the system, some of the body segments relative motions and forces are given as inputs in the model. In order to integrate the adaptive elastic foot in the rigid bodies system a numerical model of the foot is built using the finite element method and then reduced by static condensation. The reduced elastic model is then integrated in the rigid bodies’ model of the human gait. This model is used to simulate the stance period of the human gait. Four parameters, the vertical ground reaction force (GRF), the body centre of mass (BCoM), the ankle joint moment and the hip joint rotation are considered as defining characteristics of the human gait. These characteristics are used in the evaluation of the model results and latterly in the evaluation of the adaptive foot usefulness. The simulation model is validated through comparison with experimental results of the human gait. The model shows good consistency with experimental results and can be further used in simulating the human gait using prosthetic feet with different mechanical properties and positions. Different prosthetic foot properties and walking conditions are studied for the adaptive elastic prosthetic foot. The stiffness of the foot sole is changed for normal walking on level and inclined surfaces and for fast walking on level surfaces. The changes in stiffness show changes in the vertical BCoM motion which improve the gait form for walking faster than the normal walking speed but show no significant changes on the other parameters. The ankle joint inclination is also changed for walking on uphill inclined surfaces; the results show that increasing the inclination angle reduces the vertical GRF and increases the horizontal motion of the BCoM and relatively the step size, which improves the uphill motion on inclined surfaces. Also designs of beam elements with changeable stiffness that could be used in an adaptive prosthetic foot’s sole are considered. In this part two concepts are developed and studied theoretically then two models are manufactured and proved experimentally. The results show good changes in the stiffness of the models, then the first model consisting of two plates sliding one in the other shows experimentally a change of ± 8.5% in the stiffness and the second model consisting of two plates screwed together gives experimentally an average change of ±18% in the stiffness. Since these models are designed to be used as replacements for human limbs (where the available external energy sources are limited) attention was given to model a light weight system with minimum energy consumption for controlling and driving it. Also attention was given to design a system that could be used with the different commercially available prosthetic feet without the need to make large changes in the original models designs and sizes.

abstract: Lower-limb prosthesis users have commonly-recognized deficits in gait and posture control. However, existing methods in balance and mobility analysis fail to provide sufficient sensitivity to detect changes in prosthesis users' postural control and mobility in response to clinical intervention or experimental manipulations and often fail to detect differences between prosthesis users and non-amputee control subjects. This lack of sensitivity limits the ability of clinicians to make informed clinical decisions and presents challenges with insurance reimbursement for comprehensive clinical care and advanced prosthetic devices. These issues have directly impacted clinical care by restricting device options, increasing financial burden on clinics, and limiting support for research and development. This work aims to establish experimental methods and outcome measures that are more sensitive than traditional methods to balance and mobility changes in prosthesis users. Methods and analysis techniques were developed to probe aspects of balance and mobility control that may be specifically impacted by use of a prosthesis and present challenges similar to those experienced in daily life that could improve the detection of balance and mobility changes. Using the framework of cognitive resource allocation and dual-tasking, this work identified unique characteristics of prosthesis users’ postural control and developed sensitive measures of gait variability. The results also provide broader insight into dual-task analysis and the motor-cognitive response to demanding conditions. Specifically, this work identified altered motor behavior in prosthesis users and high cognitive demand of using a prosthesis. The residual standard deviation method was developed and demonstrated to be more effective than traditional gait variability measures at detecting the impact of dual-tasking. Additionally, spectral analysis of the center of pressure while standing identified altered somatosensory control in prosthesis users. These findings provide a new understanding of prosthetic use and new, highly sensitive techniques to assess balance and mobility in prosthesis users.<br>Dissertation/Thesis<br>Doctoral Dissertation Biomedical Engineering 2017

碩士<br>國立陽明大學<br>醫學工程研究所<br>98<br>Background: The direct skeletal attachment of prosthetic limbs (osseointegrated prostheses) has been suggested to be an excellent alternative to lower-limb amputees having problems with their traditional prostheses. However, it has not been adopted universally due to the issues of ensuring mechanical fixation to the bone. Considerations are given to mechanisms of mechanical failure of the implant system and the femur as well as bone-remodeling subsequent to the altered loading conditions. Method: Using “Finite element model” to simulate the actual conditions. To establish the femur and the market standard bone screw model. Femur node ranger is 14935~15532, element range is 63811~70112; bone screw node range is 8710~8922, element range is 26002~27712. Using C3D4 is as element type. In this proposed study, loading regimes from this group’s previous force measurements of transfemoral amputees using osseointegrated prostheses will be simulated. Bone density dropped up to 25%、40%，thread length is 30mm、60mm、105mm、120mm、150mm. Attempt will be made to predict mechanical failure of the bone and the implant system and bone-remodeling using the computed stresses and some developed theories. required. Result: It shows that smooth stress distribution by the fillet and lend angle in medical bone screw. Osseointegrated lower limb prosthesis is only for bone density 40% higher than the normal one. The ratio of bone screw and residual limb length to be 1:2 will have the best beneficial result. It can decrease bone and implant stress when the osseointegration is more complete, the interface is more nearly bonded. Conclusion: According to the theory that the maximum principal stress is over the yield strength of implant, the biggest interferences that the bone can endure were obtained. For future, we want to change the abutment design if it possible leads bone stress decreased. This study suggests the importance of assessing the bone quality for amputees receiving implanted prostheses, and rehabilitation to promote bone growth Showing the possibility of bone fracture in osteoporosis with higher load conditions when using an osseointegrated prosthesis.

abstract: Robotic lower limb prostheses provide new opportunities to help transfemoral amputees regain mobility. However, their application is impeded by that the impedance control parameters need to be tuned and optimized manually by prosthetists for each individual user in different task environments. Reinforcement learning (RL) is capable of automatically learning from interacting with the environment. It becomes a natural candidate to replace human prosthetists to customize the control parameters. However, neither traditional RL approaches nor the popular deep RL approaches are readily suitable for learning with limited number of samples and samples with large variations. This dissertation aims to explore new RL based adaptive solutions that are data-efficient for controlling robotic prostheses. This dissertation begins by proposing a new flexible policy iteration (FPI) framework. To improve sample efficiency, FPI can utilize either on-policy or off-policy learning strategy, can learn from either online or offline data, and can even adopt exiting knowledge of an external critic. Approximate convergence to Bellman optimal solutions are guaranteed under mild conditions. Simulation studies validated that FPI was data efficient compared to several established RL methods. Furthermore, a simplified version of FPI was implemented to learn from offline data, and then the learned policy was successfully tested for tuning the control parameters online on a human subject. Next, the dissertation discusses RL control with information transfer (RL-IT), or knowledge-guided RL (KG-RL), which is motivated to benefit from transferring knowledge acquired from one subject to another. To explore its feasibility, knowledge was extracted from data measurements of able-bodied (AB) subjects, and transferred to guide Q-learning control for an amputee in OpenSim simulations. This result again demonstrated that data and time efficiency were improved using previous knowledge. While the present study is new and promising, there are still many open questions to be addressed in future research. To account for human adaption, the learning control objective function may be designed to incorporate human-prosthesis performance feedback such as symmetry, user comfort level and satisfaction, and user energy consumption. To make the RL based control parameter tuning practical in real life, it should be further developed and tested in different use environments, such as from level ground walking to stair ascending or descending, and from walking to running.<br>Dissertation/Thesis<br>Doctoral Dissertation Electrical Engineering 2020

Although dynamic prosthetic alignment is an important process for the rehabilitation of transtibial amputees, such alignment technique is subjective and inconsistent. Using biomechanical variables and questionnaire assessments, this study compared an instrument-assisted dynamic alignment technique using the Compas™ system and conventional alignment techniques on nine adults with unilateral transtibial amputation. A focus group discussion was conducted with six prosthetists to understand clinical practice of dynamic alignment and their perception of the Compas™ system. Results found that Compas™ produced more anterior weight line displacement and greater varus moment on the prosthesis than conventional alignment techniques. Alignment changes did not affect pelvic acceleration, and the instrument-assisted alignment technique produced certain biomechanical changes but not necessarily better alignments. Although the current version of the Compas™ system is not clinically feasible, it can be used as a teaching/justification tool. Further investigation with larger sample size and ankle alignment or moment measures is needed.