Anthropomorphically Inspired Design of a Tendon-Driven Robotic Prosthesis for Hand Impairments

This thesis presents the design of a robotic prosthesis, which mimics the morphology of a human hand. The primary goal of this work is to develop a systematic methodology that allows a custom-build of the prosthesis to match the specific requirements of a person with hand impairments. Two principal research questions are addressed toward this goal: 1) How do we cater to the large variation in the distribution of overall hand-sizes in the human population? 2) How closely do we mimic the complex morphological aspects of a biological hand in order to maximize the anthropomorphism (human-like appearance) of the robotic hand, while still maintaining a customizable and manageable design? This design approach attempts to replicate the crucial morphological aspects in the artificial hand (the kinematic structure of the hand skeleton, the shape and aspect ratios of various bone-segments, and ranges of motion). The hand design is partitioned into two parts: 1) A stiff skeleton structure, comprising parametrically synthesized segments that are simplified counterparts of nineteen bone-segments—five metacarpals, five proximal phalanges, four middle phalanges, and five distal phalanges—of the natural hand-skeleton and simplified mechanical substitutes of the remaining eight carpal bones. 2) A soft skin-like structure that encompasses the artificial skeleton to match the cosmetics and compliant features of the natural hand. A parameterized CAD model representation of each synthesized segment is developed by using the feature of design-tables in SolidWorks, which allows easy customization with respect to each person. Average hand measurements available in the literature are used to guide the dimensioning of parameters of each synthesized segment. Tendon-driven actuation of the fingers allows the servo actuators to be mounted remotely, thereby enabling a sleek finger design. A prototype of the robotic hand is constructed by 3D-printing all the parts using an Object 30 Prime 3D printer. Results reported from physical validation experiments of the robotic hand demonstrate the feasibility of the proposed design approach

Development of a Body-powered Hand Prosthesis with Flexible Materials by Additive Manufacturing

The research on prostheses made by Additive Manufacturing (AM) has been increasing, as they solve some of the issues of the most common prostheses. However, despite their growth, these prostheses have a high rejection rate, especially in children, due to their low level of anthropomorphism. The main goal of this study was to develop an aesthetically appealing three-dimensional (3D) printed body-powered prosthesis for a four-year-old child with a transverse metacarpal total deficiency. The development of the prosthesis started through an assessment of the anatomical features of the extremities of patient’s both upper limbs, performed with body casting, simple measurements and 3D-scanning of the cast. The whole prosthesis was designed using the Fusion 360 CAD software and produced using The Original Prusa i3 MK3S and polylactic acid (PLA) and Filaflex filaments. The prosthesis was designed through an iterative process, whereby the prosthesis’ appearance and functionality were optimised. During the design stages, several design configurations and printing settings were tested. Some printed models were evaluated using pull tests. The developed prosthesis possessed a high level of anthropomorphism, consisting of a solution that is quite similar to a human hand. Despite all the generated concepts focused on increasing the performance of 3D-printed body-powered prostheses, the developed prosthesis presented a low functionality. However, the device was cheaper and lighter than the existing 3D-printed body-powered prostheses. Moreover, the performed tests revealed that a better printing quality implied higher forces to flex the prosthesis and consequently, lower functionality. The final prototype was presented to the child and his family, which provided their feedback using the System Usability Survey and a custom-made assessment questionnaire. The resulting scores classified the device as "Excellent". Despite being promising, further work is still required for this device to be used by children with upper limb defects.A investigação em próteses feitas através de Manufatura Aditiva tem aumentado, uma vez que as mesmas solucionam alguns dos problemas das próteses mais comuns. Porém, apesar deste crescimento, estas próteses apresentam uma elevada taxa de rejeição, principalmente em crianças, devido ao seu baixo nível de antropomorfismo. O objetivo principal deste estudo consistiu no desenvolvimento de uma prótese body-powered esteticamente apelativa, impressa a três dimensões, para uma criança de quatro anos com uma deficiência total transversal do metacarpo. O desenvolvimento da prótese começou com uma avaliação das características anatómicas das extremidades de ambos os membros superiores do paciente, realizada através de extração de moldes, medições simples e scanning tridimensional dos moldes. Toda a prótese foi desenhada com o software Fusion 360 CAD e produzida através da impressora The Original Prusa i3 MK3S com filamentos de ácido polilático (PLA) e Filaflex. A prótese foi desenvolvida através de um processo iterativo, em que a aparência e a funcionalidade da prótese foram otimizadas. Durante as fases de design, foram testadas várias configurações de design e impressão. Alguns modelos impressos foram avaliados através de testes de tração. A prótese desenvolvida possui um elevado nível de antropomorfismo, consistindo numa solução bastante semelhante a uma mão humana. Apesar de todos os conceitos gerados com o objetivo de aumentar o desempenho das próteses body-powered impressas a três dimensões, a prótese desenvolvida apresentou uma baixa funcionalidade. No entanto, o dispositivo é mais barato e mais leve do que outras próteses body-powered impressas a três dimensões. Além disso, os testes realizados revelaram que uma melhor qualidade de impressão implica maiores forças para flexionar a prótese e, consequentemente, uma menor funcionalidade. O protótipo final foi apresentado à criança e sua família, os quais forneceram feedback através do questionário de usabilidade "System Usability Survey" e de um questionário personalizado. As pontuações resultantes classificaram o dispositivo como "Excelente". Apesar de promissor, é necessário trabalho futuro para que este dispositivo seja utilizado por crianças com deficiências dos membros superiores

On the development of a cybernetic prosthetic hand

The human hand is the end organ of the upper limb, which in humans serves the important function of prehension, as well as being an important organ for sensation and communication. It is a marvellous example of how a complex mechanism can be implemented, capable of realizing very complex and useful tasks using a very effective combination of mechanisms, sensing, actuation and control functions. In this thesis, the road towards the realization of a cybernetic hand has been presented. After a detailed analysis of the model, the human hand, a deep review of the state of the art of artificial hands has been carried out. In particular, the performance of prosthetic hands used in clinical practice has been compared with the research prototypes, both for prosthetic and for robotic applications. By following a biomechatronic approach, i.e. by comparing the characteristics of these hands with the natural model, the human hand, the limitations of current artificial devices will be put in evidence, thus outlining the design goals for a new cybernetic device. Three hand prototypes with a high number of degrees of freedom have been realized and tested: the first one uses microactuators embedded inside the structure of the fingers, and the second and third prototypes exploit the concept of microactuation in order to increase the dexterity of the hand while maintaining the simplicity for the control. In particular, a framework for the definition and realization of the closed-loop electromyographic control of these devices has been presented and implemented. The results were quite promising, putting in evidence that, in the future, there could be two different approaches for the realization of artificial devices. On one side there could be the EMG-controlled hands, with compliant fingers but only one active degree of freedom. On the other side, more performing artificial hands could be directly interfaced with the peripheral nervous system, thus establishing a bi-directional communication with the human brain

Development of an Upper Limb Myoelectric Prothesis in Flexible/Hybrid Material, for Application in Young Patients

With the recent developments in the Additive Manufacturing (AM) industry, new methods of prostheses production have taken over the prosthetic industry. These new prostheses models produced using 3-Dimensional (3D)-printing methods solve some of the issues of the most common prostheses, such as cost and weight, but, despite their growth, still present high rejection rates, especially in children. These rejections are mostly related to the low levels of anthropomorphism and limitations in terms of functionality associated to 3D printed prostheses. The main goal of this study was to develop an aesthetically appealing 3D printed myoelectric prosthesis for a four year old child with a transverse metacarpal total deficiency. The development of the prosthesis was based on the assessment and improvement of current 3D printable prosthetic models, and the integration of a myoelectric classifier and the electronic components into the model. The whole prosthesis was designed using a combination of the Fusion 360 CAD and SolidWorks CAD 2021 softwares, and produced using The Original Prusa i3 MK3S with polyactic acid (PLA) or Filaflex filaments. The prosthesis was designed through an iterative process, where several prototypes were developed in order to optimise its appearance and functionality. Some printed models were subjected to pull tests, that evaluated its flexibility and allowed the development of the electronic sector of the prosthesis. The developed prosthesis possessed a high level of anthropomorphism and functionality, consisting of a solution that is quite similar to the human hand and was able to simulate the intended movements, although with some limitations. Additionally, the device was relatively cheap and light when compared to existing 3D-printed myoelectric prostheses. Although this thesis has some limitations, it certainly contributed to clarify many of the doubts that still exist in the scientific community. Hopefully, it will help to further develop the prosthetic industry.Nos últimos anos, o desenvolvimento de técnicas de Manufactura Aditiva (MA) tem permitido a evolução nos métodos de produção de próteses. Esses novos modelos de próteses produzidos usando métodos de impressão 3D resolvem alguns dos problemas das próteses mais comuns no mercado, como custo e peso, mas, apesar destes avanços, ainda apresenta altas taxas de rejeição, principalmente em crianças. Essas taxas de rejeição estão muitas vezes relacionadas com os baixos níveis de antropomorfismo e funcionalidade destes modelos. O principal objetivo deste estudo tornou-se então desenvolver uma prótese mioelétrica esteticamente atraente, produzida através de impressão 3D, para ima criança de quatro anos e com deficiência total do metacarpo transverso. O desenvolvimento da prótese deu-se por meio da avaliação do modelos atuais de próteses produzidos por impressão 3D, melhoria das suas características e integração de um classificador mioeletrico e os componentes eletrônicos associados. A prótese foi toda projetada usando uma combinação dos softwares Fusion 360 CAD e SolidWorks CAD 2021 e produzido utilizando a The Original Prusa i3 MK3S e filamentos de PLA ou Filaflex. A prótese foi concebida através de um processo iterativo, onde vários protótipos foram desenvolvidos de forma a otimizar a sua aparência e funcionalidade. Alguns dos modelos impressos foram submetidos a testes de tração, de forma a avaliar a sua flexiblidade e desenvolver as componentes eletrónicas da prótese. A prótese desenvolvida possuía um alto nível de antropomorfismo e funcionalidade, obtendo-se uma solução bastante semelhante à mão humana capaz de simular, embora com algumas limitações, os movimentos pretendidos. Além disso, o dispositivo é relativamente barato e leve quando comparado com outros modelos de próteses produzidos por impressão 3D. Embora o protótipo final tenha algumas limitações, certamente contribui para o desenvolvimento do modelo prótetico e esclarece alguns dos problemas em modelos antigos. Espera-se que este estudo ajude a aprofundar e desenvolver a indústria das próteses

Design of a non-invasive device to measure bone strength recovery of distal radius fractures for use with HR-pQCT Imaging

Distal radius fractures are the most common bone injury in adults, with the majority occurring in postmenopausal women. Often these fractures result in painful healing defects, leading to extended treatment and even surgery. Currently, there is no clinical method to quantify the extent of bone healing beyond the limited capabilities of standard x-rays. The goal of this project is to develop a device, which can determine the strength of a healing fracture. This is achieved by applying a known bending load to the distal radius and measuring the displacement of the bone in High Resolution CT images. The device created was manufactured via 3D printing. Validation of device performance was performed using cadaver wrist models

Investigation of 3DP technology for fabrication of surgical simulation phantoms

The demand for affordable and realistic phantoms for training, in particular for functional endoscopic sinus surgery (FESS), has continuously increased in recent years. Conventional training methods, such as current physical models, virtual simulators and cadavers may have restrictions, including fidelity, accessibility, cost and ethics. In this investigation, the potential of three-dimensional printing for the manufacture of biologically representative simulation materials for surgery training phantoms has been investigated. A characterisation of sinus anatomical elements was performed through CT and micro-CT scanning of a cadaveric sinus portion. In particular, the relevant constituent tissues of each sinus region have been determined. Secondly, feedback force values experienced during surgical cutting have been quantified with an actual surgical instrument, specifically modified for this purpose. Force values from multiple post-mortem subjects and different areas of the paranasal sinuses have been gathered and used as a benchmark for the optimisation of 3D-printing materials. The research has explored the wide range of properties achievable in 3DP through post-processing methods and variation of printing parameters. For this latter element, a machine-vision system has been developed to monitor the 3DP in real time. The combination of different infiltrants allowed the reproduction of force values comparable to those registered from cadaveric human tissue. The internal characteristics of 3D printed samples were shown to influence their fracture behaviour under resection. Realistic appearance under endoscopic conditions has also been confirmed. The utilisation of some of the research has also been demonstrated in another medical (non-surgical) training application. This investigation highlights a number of capabilities, and also limitations, of 3DP for the manufacturing of representative materials for application in surgical training phantoms

Modeling & Analysis of Design Parameters for Portable Hand Orthoses to Assist Upper Motor Neuron Syndrome Impairments and Prototype Design

Wearable assistive robotics have the potential to address an unmet medical need of reducing disability in individuals with chronic hand impairments due to neurological trauma. Despite myriad prior works, few patients have seen the benefits of such devices. Following application experience with tendon-actuated soft robotic gloves and a collaborator\u27s orthosis with novel flat-spring actuators, we identified two common assumptions regarding hand orthosis design. The first was reliance on incomplete studies of grasping forces during activities of daily living as a basis for design criteria, leading to poor optimization. The second was a neglect of increases in muscle tone following neurological trauma, rendering most devices non-applicable to a large subset of the population. To address these gaps, we measured joint torques during activities of daily living with able-bodied subjects using dexterity representative of orthosis-aided motion. Next, we measured assistive torques needed to extend the fingers of individuals with increased flexor tone following TBI. Finally, we applied this knowledge to design a cable actuated orthosis for assisting finger extension, providing a basis for future work focused on an under-represented subgroup of patients

Design and Development of a Myoelectric Transradial Prosthesis

The loss of a limb is a life-changing event and reality for 441,000 transradial amputees in the United States. Limb loss can have substantial physical, social, psychological, and economic consequences. A prototype prosthesis was created that has sophisticated hand functionality, an adjustable and comfortable socket, and a lightweight yet durable design utilizing 3D printing, all available at a reasonable price point. The prosthesis integrated force sensors, servo motors, and a myoelectric means of control so the user may perform activities of daily living. The overall outcome was a prosthesis that met its design requirements, offering increased usability, functionality, and availability

Design and Development of a Myoelectric Transradial Prosthesis

The loss of a limb is a life-changing event and reality for 441,000 transradial amputees in the United States. Limb loss can have substantial physical, social, psychological, and economic consequences. A prototype prosthesis was created that has sophisticated hand functionality, an adjustable and comfortable socket, and a lightweight yet durable design utilizing 3D printing, all available at a reasonable price point. The prosthesis integrated force sensors, servo motors, and a myoelectric means of control so the user may perform activities of daily living. The overall outcome was a prosthesis that met its design requirements, offering increased usability,functionality, and availability