Background: Commercially available upper limb prostheses for playing guitar require professional assistance for proper fitting and usage. For people who lack this opportunity, alternatives are offered as research models or open-source models. However, adjustable models still require fitting assistance while parameter adjustment is extremely limited. This limits the user’s ability to play more complex music.

Goal: This project proposes the design of a low-cost passive adjustable 3D printed upper limb prosthesis for people with no access to professional prosthetic assistance.

Methods: Both design and evaluation methods were applied. Regarding design, early concepts were designed and selected using a Morphological table and Harris profile, applying rapid prototyping for initial comparison. Regarding evaluation, a parameter measurement and a device functionality test with users with and without upper limb differences were performed.

Results: The final model was successfully printed using Fused Deposition Modeling. The model was evaluated via parameters measurements and a user device functionality test. Results showed that the device allowed the user to put the elbow as a reference point to aid mental mapping of the prosthesis. Speed and accuracy measured during the test suggest a positive outcome for end users.

Conclusion: This design presents an accessible and reliable solution for users with upper limb differences who want to improve their guitar playing skills without the need of professional assistance.

This research focuses on the design and evaluation of a fully passive variable damping transfemoral prosthesis, aiming to provide a low-cost alternative to existing microprocessor-controlled prosthetic knees (MPKs). Current MPKs, such as the Otto Bock C-Leg 4 and Össur Rheo Knee XC, offer advanced functionality by adjusting knee damping based on sensory input. However, their high cost make them inaccessible to many individuals, particularly in low-income regions. This study addresses this issue by developing a fully passive low-cost transfemoral prothesis with variable knee damping in the swing phase.

The design process involved defining functional requirements, identifying key subfunctions, and generating three concept designs.

The final design provides stability in the stance phase and controlled motion during the swing phase. The main innovation of this design is a centrifugal force-based damping mechanism. The foot’s centrifugal acceleration generates a force that is transmitted through a cable system to a friction brake in the knee joint, effectuating velocity-dependent damping. Additionally, knee stability in the stance phase is ensured by a spring latch lock mechanism, which engages at the end of the swing phase and disengages at the end of the stance phase through ankle dorsiflexion. An ankle spring mechanism provides ankle stability in the stance phase, and it provides energy for push-off. The final design is produced using laser-cut metal, 3D-printed components, and off-the-shelf parts to keep production costs low.

The evaluation phase included two key tests:

\textit{Swing phase test} – Assessed the velocity-dependent damping mechanism by suspending the prosthesis and measuring knee moment at various angular velocities. The results showed some velocity-dependent damping, but inconsistencies due to hysteresis were observed.

\textit{Ankle stiffness test} – Evaluated the rotational stiffness of the ankle joint using force and displacement measurements. The results showed slightly lower than expected ankle stiffness.

While the prototype shows the feasibility of a fully passive variable damping knee, several limitations were identified. The main limitation was that significant hysteresis was present the damping mechanism, leading to inconsistent results. Furthermore, the swing phase was performed only at walking speeds lower than occur at natural gait, so no conclusion can be drawn on its effectiveness in real world use.

Future research should focus on improving the robustness of the damping mechanism, reducing the hysteresis and conducting full gait cycle tests on human subjects. Additionally, implementing a delay between force sensing and damping activation could enhance the resemblance to natural gait.

In conclusion, this study demonstrates that a low-cost, fully passive variable damping prosthetic knee is possible, demonstrating a promising initial step towards the development of low-cost \textit{K3} prostheses. However, further development and testing is required before the design can be classified as a functional \textit{K3} prosthesis.

Background: Computational musculoskeletal models are valuable for understanding finger biomechanics and aiding in medical applications such as postoperative therapy and surgical planning. These models simulate various scenarios and predict outcomes by representing the biomechanical system through equations of motion. However, the complex mechanics of the human finger, particularly the role of the Lateral Bands in coordinated joint flexion, have primarily been studied in static simulations. Their role in dynamic simulations, especially with the inclusion of other key tendons and ligaments, has not been researched.
Aim: This study aims to develop a musculoskeletal model to enhance our understanding of the contribution of Lateral Bands to coordinated finger flexion, by combining insights from previous research to address existing gaps in finger biomechanics. The model will replicate the anatomical joints and Lateral Band structures of an anthropomorphic mechanical finger, offering a simplified design to reduce simulation complexity and enhance verification reliability.
Method: An adapted anthropomorphic mechanical finger was created based on previous work, scaled down to reduce weight and required actuation force. The simulation model was developed in OpenSim, using bone geometries from CAD files and direct measurement attachment location of tendons and ligaments from the mechanical finger for improved accuracy. Model verification involved comparing the model’s behavior with the mechanical finger through experiments focusing on finger flexion under external deep flexor tendon load, using motion capture data, inverse kinematics (IK), and forward dynamics (FD). Results The simulation model accurately replicated the mechanical finger’s joint kinematics, with an average squared error ranging from 1.54e−3 mm to 9.55e−3 mm and an average marker RMSE of ±0.65 mm. Tendon displacement and moment arm were verified with average errors ±1 mm and ±1.23 mm, respectively, indicating that the model closely matches the mechanical finger’s tendon force and joint torque relationships. The model demonstrated that Lateral Bands are essential for interphalangeal joint (IPJ) coupling, as they adjust their tension by becoming taut or slack during finger flexion to distribute forces effectively. Without these Lateral Bands, finger flexion leads to unrealistic joint movements in mechanical finger models. Additionally, the Lateral Bands play a significant role in generating tension in the deep flexor tendon during IPJ coupling.
Conclusion: This study demonstrated the role of Lateral Bands during dynamic finger flexion by incorporating anatomically-based structures and replicating their behavior. The findings provide deeper insights into their function and set a new foundation for future research. Additional studies could further explore how Lateral Bands influence force distribution and joint mechanics, potentially leading to better understanding and treatment of finger injuries and disorders.

Background : There have been several advancements in modelling the behaviour of the finger and its internal anatomical structures and in the development of anthropomorphic fingers. Most studies that include ligaments focus on force distribution in the tendon-ligament network for a particular task. In the design of anthropomorphic fingers, especially in two recent projects, ligament attachments have been decided through iterative trials and the the tendon network has been used to control the range of motion of the finger. However, the collateral ligaments also play a major role in limiting the range of motion of the finger in addition to contributing to medial-lateral joint stability.
Aim : The aim of this project is to develop an algorithm to automatically compute coordinates for collateral ligament attachment sites for the Distal Inter-Phalangeal (DIP) joint of the finger, given a required range of motion in terms of maximum flexion and extension angles.
Method : The DIP joint was described in two dimensions (in the sagittal plane) with one degree of freedom (flexion-extension). Constraints were formulated based on geometry and observed and reported ligament length ranges. The model formulation was also informed by insights from the dissection of three preserved human index fingers. The algorithm named ’Auto-LINC’ (Automating Ligament Insertion Coordinates) involved two stages. The first was a combinatorial approach used to establish the best possible combination of attachment sites out of a set of feasible solutions. This was used to seed the second stage - a continuous domain approach used for local optimisation. The algorithm was designed in such a way that the two stages can be used separately or in combination depending on the application.
Results : The attachment sites computed using the combined approach were used to add ligaments to an existing OpenSim simulation model of an anthropomorphic DIP joint to verify that the required range of motion was achieved. The process was illustrated with an example in which 99.6% of the required range of motion was achieved using ligaments with attachment sites computed by Auto-LINC.
Discussion : The use of an algorithm with geometric constraints and objective function yielded feasible solutions in a short time. By adapting the constraints to suit differences in geometry, Auto-LINC
can also be used to predict collateral ligament attachment sites for other flexion-extension joints such as the Proximal Inter-Phalangeal (PIP) joint. Auto-LINC has potential for use in the design of anthropomorphic fingers as it automates the process of deciding ligament attachment sites. It also has potential for use in guiding robot-assisted reconstruction surgery. It can be made more detailed and versatile by adding material properties and constitutive equations and by extension into three dimensions.
Conclusion : Auto-LINC is already usable in its current form to compute form based on function, and has potential for use in automating anthropomorphic design and guiding reconstruction surgery. In
contrast to other published research, Auto-LINC computes ligament attachment sites based on range of motion - in other words, it focuses on moving from function to form rather than form to function.

Background: Currently, there is no accurate method to objectively assess transtibial prosthetic socket fit. This study aims to evaluate the use of infrared thermography (IRT) to analyse temperature changes in response to pressure points, and their relation to pain and comfort assessments. This study also explores the reliability and agreement parameters of IRT.
Methods: A within-subject study was conducted on seven participants wearing a vacuum or pin suspension socket. Each participant was examined with two sockets: their prescribed socket (unmodified) and their prescribed socket modified with added pressure pads inside the prosthetic socket at the fibular head and distal tibia end. Thermal images were obtained after 10 minutes of walking with the unmodified socket (TW1), after a subsequent 15-minute resting period (TR1), after 10 minutes of walking with the modified socket (TW2), and after a second resting period (TR2). Difference maps showing temperature changes relative to the baseline (TR1) were created. Subjective assessments included localised pain and Socket Comfort Scores. Regions of interest (ROI) for temperature analysis were selected at the fibular head, distal tibia end, popliteal fossa, and gastrocnemius belly. Reliability and agreement were assessed using the Intraclass Correlation Coefficient (ICC), standard error of measurement (SEM), SEM%, smallest detectable change (SDC), SDC%, and Bland-Altman plots.
Results: Visual inspection and ROI temperature values revealed hotspots in 86% (6/7) of participants at the fibular head post-walking with the modified socket, contrasting with the unmodified socket in the majority of cases. Pain corresponded with the presence of hotspots at this location. Hotspots at the distal tibia end post-walking with the modified socket were observed in 43% (3/7) of participants, but without apparent difference from the unmodified socket. Only two-thirds of these coincided with reported pain. Reliability of IRT was very good to excellent across the residual limb and ROIs (ICC ≥ 0.85), except for fair reliability at the fibular head ROI (ICC 0.55). For TR1 and TR2 test-retest agreement, SEM ranged from 0.3 °C (1.0%) to 0.7 °C (2.1%), with SDC from 0.9 °C (2.8%) to 2.0 °C (5.9%). On the difference maps of unmodified and modified sockets, SEM ranged from 0.6 to 0.8 °C, and SDC from 1.7 to 2.1 °C.
Conclusion: Based on the observed thermal response to pressure in the majority of cases, IRT demonstrated potential in identifying peak pressure points and pain through increased temperature measurements at the fibular head, but had limited capability in detecting these at the distal tibia end. This limitation is likely due to differences in circulation, socket suspension effects, and uncertainty about the exerted pressure. Future research should simplify the protocol to enhance clinical applicability, enabling IRT to complement subjective socket fit assessments and improve prosthetic socket designs and patient outcomes.

Prosthetic care is often inaccessible in Low and Middle-Income Countries (LMICs) due to limited resources and lack of trained professionals. Additionally, prosthetic sockets are frequently abandoned due to poor fit, discomfort, and inability to accommodate residual limb volume changes. 3D-printing, Computer-Aided Design (CAD), and adjustable prosthetic sockets offer solutions to increase access to prosthetic care in LMICs. This study aims to design an adjustable 3D-printed transradial prosthetic socket, and a simple and robust fitting method tailored for use in LMICs. The focus is on customisation, patient comfort, and ease of production and implementation by local prosthetists. An adjustable 3D-printed transradial prosthetic socket was designed using the ACCREx method to expand the solution space. Concepts were formed through a morphological chart. The final designs were converted into simulation models suited for non-amputees. These models were then fitted, customized, and evaluated. Both objective and subjective data verified and validated the designs, emphasizing functionality, comfort, practicality, and compatibility between the prosthetic socket and fitting method. The prosthetic socket is fully 3D-printed and features proximal-distal rings and a condyle brace with a reversible zip-tie-inspired adjustment mechanism. The fitting method includes a modular fitting model and a (semi-)automated parametric CAD-model. Results indicated sufficient compatibility between the prosthetic socket and fitting method, and a generally perceived correct socket fit. The fitting method enables easy socket customisation, requiring minimal training and active labour. This study offers a proof of concept for an easier, more robust, and less labour-intensive solution for comfortable prosthetic socket customisation, suited for LMICs. The developed 3D-printed prosthetic socket and fitting method represent a significant step towards accessible prosthetic sockets in LMICs and the global democratisation of prosthetic care.

Optimal settings and designs for prosthetic parameters, such as knee stiffness, are required to achieve effective and stable sit-to-stand (STS) movements for individuals with lower limb prostheses but remain inadequately defined. One possible solution is prosthetic modeling and predictive simulations. However, current literature primarily focuses on inverse kinematics, inverse dynamics, and most likely, gait. There remains a gap in optimizing the parameters during STS movement through predictive simulation. By utilizing SCONE (Simulated Controller OptimizatioN Environment for predictive simulating), this study aims to find the optimized prosthetic parameters and investigate the effect of varying transfemoral prosthetic knee joint stiffness on biomechanics and validate this approach. A modified musculoskeletal model with a prosthesis and neuromuscular controllers are combined for predictive sit-to-stand simulation. The control parameters for neuromuscular controllers and the prosthetic parameters are optimized by SCONE with predefined objective functions to obtain energy-oriented results. The simulation results were analyzed in terms of joint load, stability, kinematics, and energy cost. Lastly, the results were validated by comparison with an existing experimental dataset. The simulations indicated that prosthetic knee stiffness affects joint loads, stability, kinematics, and energy expenditure during STS movements. Higher knee stiffness generally leads to increased prosthetic side joint loads and contribution but requires higher damping ratios to ensure a successful STS movement, while extreme stiffness should be avoided. Optimal stiffness settings were identified near 70 Nm/rad with the damping ratio of 22 Nms/rad. Validation shows the feasibility of this approach as well as its limitations. This study demonstrates the potential and insights of predictive simulations in optimizing prosthetic knee parameters. However, the current approach is limited by the model, methodological, theoretical, and practical issues. Therefore, further validation and refinement are necessary. Future work may focus on building complex and customized models and exploring other movements.

The knee is the most common joint affected by osteoarthritis (OA). Evaluating knee cartilage in MRI is usually done under non-loading conditions. However, load-bearing is a key capacity of cartilage, so using compression may be a tool for clinicians to identify early OA. A loading device could simulate weight-bearing conditions in a supine position. This report presents the development of an MRI-compatible knee loading device, following the double diamond method and the V-model.

The most important requirement are that the device must apply an axial, accurate, and adjustable load through the foot to the patient’s knee in a supine position. The device should be able to apply different small knee flexion angles. Existing loading devices, MRI procedures, knee biomechanics, and potential risks were analyzed to establish a comprehensive set of requirements. A knee loading device has been developed where a balance needed to be found between feasibility, functionality and complexity, with feasibility as the main priority to ensure a working foundation for further enhancements.

A biomechanical analysis was conducted to understand the impact of applying compression to the knee in a supine position on the internal joint moments, which reflects the effort that needs to be provided by the patient. Adjustments in knee flexion angle and the height of the applied load at the foot were made to evaluate their effect. The results showed that a 10° knee flexion with a load application through the ankle requires the least effort from the patient, making it the most feasible loading condition to maintain stable for several minutes. For the design, this meant that the height of the footplate was set twice the distance between the bottom of the calcaneus and the position where the load goes through the ankle. Although 10° knee flexion might the most feasible loading condition, it does not necessarily mean it is
the best indicator for early OA. Therefore, the device still needs to enable different knee flexion angles.

The load is applied at the foot through a footplate, which slides along axes. To generate the load, elongating elastic material was chosen because of its practicality and safety. Suspended weights were excluded, as they require an inconvenient set-up and are not safe in case of emergency. Since a setup with suspended weights requires more space and covers both the patient bed and MRI table, it is not possible to disconnect the MRI table from the MRI scanner rapidly. The final design of the MRI knee loader ensures the patient can be positioned, and the load could be applied without having to change the position. To make the load generation feasible for radiology laboratory personnel, a driving wheel and pulley systems were incorporated to reduce the force required at the wheel. Additionally, a knee support is implemented to apply a knee flexion angle to the patient.

A prototype has been manufactured to evaluate the functional application of the applied load and knee flexion angle, as well as patient compatibility. It included the essential functional components: the footplate, knee support and the plates they are connected to. The prototype demonstrated the capability of applying a load to the foot in an experimental set-up. A linear relation was found between the input force and the measured force at the footplate, mimicking the load that is applied at the foot. Unfortunately, the measured force was not sufficiently accurate and the variation between the repeated measurements was found substantial. It was argued that this was due to the friction in the current design.

Further design improvements are required to overcome the limitations of this design. Compromises were done to improve feasibility, but it could be analysed how the functionality and accuracy could be improved. A starting point could be to find a better fit between the bearings in the footplate and the axes, to reduce friction and ensure a more accurate application of the load. The footplate should be redesigned so it does not clamp. Moreover, the complete final design of the MRI knee loader (including the footplate, knee support and their connection plate, as manufactured in the prototype, as well as the driving wheel and the table with the double bottom embedding the cable and elastic) must be produced to verify and validate the device’s overall functionality, patient compatibility, suitability within the MRI
environment and workflows, and operational ability by the MRI laboratory personnel.

Background
Rheumatoid arthritis (RA) is a progressive, chronic, inflammatory, autoimmune disorder, affecting 0.5-1.5% of the world's population. Current RA disease activity assessment methods rely on subjective, labor-intensive methods. Therefore, an unmet need exists for objectively assessing RA disease activity through a low-labor method. It is hypothesized that a correlation exists between passive MCP joint stiffness and RA disease activity.

Objective
The objective of this study is to design, develop, and evaluate a measurement tool that can assess passive MCP joint stiffness of the index-, middle-, and ring fingers of both hands objectively. The tool will be evaluated on healthy participants.

Design methods
A structured approach is adopted for the design of the measurement tool. The design challenges are mapped out by writing down the requirements into four categories. In the next design phase, the partial functions and their corresponding potential solutions are worked out. Three concepts are developed which combine different sets of potential solutions. The most promising concept is determined through a multicriteria analysis and worked out into a final design. Before the evaluation process commences, the final design is reflected on and improved where necessary.

Evaluation methods
Firstly, the tool is verified by subjecting it to a linear torsion spring rather than a human MCP joint. Secondly, the passive resistance behavior of a human MCP joint is analyzed during a full cycle of flexing and moving back to the initial position. Thirdly, the tool is used for an inter-day evaluation to determine the precision of the tool when used on human MCP joints (expressed as coefficient of variation (CV)). Finally, a repetition test is performed to determine the influence of setup-related causes on the precision of the tool.

Results
The linear spring evaluation showed that the mechanical system of the tool is very precise, exhibiting a coefficient of variation of 0.6%. The continuous cycle evaluation showed that the passive resistance of the MCP joint behaves nonlinearly and that the MCP joints have viscoelastic properties. The calculated CV for the inter-day precision evaluation is equal to 33.0%. The CVs for the repetition tests were equal to 13.4% and 27.7% for the fixed and non-fixed approaches respectively. Other evaluated aspects are the weight of the tool (1.6 kg), volume of the tool (10.8 dm³), comfort for the user (9 out of 10), and full six-joint assessment time (7.5 min).

Discussion
The CV of 33.0% for the inter-day precision evaluation is too large to subject the tool to RA patients. However, the repetition test showed when the hand under assessment is consistently aligned and orientated, the system is much more precise, exhibiting a CV of 13.4%. So, when design components are included that assist with the alignment and orientation of the hand under assessment, the tool can be subjected to actual RA patients to evaluate the increase in passive MCP joint stiffness during (the early stages of) inflammation.

Running Specific Prostheses (RSPs) enable running for athletes with lower limb amputations. The RSP design is inspired by human ankle behaviour while running, aiming to replicate its dynamic properties. RSPs are produced using carbon fiber composites that exhibit elastic properties, allowing them to store and return energy. Unlike biological legs, RSPs cannot generate net positive mechanical power. Furthermore, current RSP designs limit ground reaction forces (GRFs) while running. In addition, current RSP designs lack stiffness adaptation to running speed, which is required to optimize running speed. Running speed is a crucial performance indicator, influenced by step length, step frequency, and ground reaction forces (GRFs). This study explores the design of an innovative RSP running blade with improved push-off and load-dependent stiffness, focusing on how it can affect running gait, speed, and user satisfaction for lower limb amputees. This research aims to provide insights into the performance of the RSP. Mechanical compression tests were performed to characterize prototype stiffness. In addition, insights into user satisfaction and running biomechanics were obtained through qualitative feedback and quantitative gait analysis from amputee participants.

Semi-active lower limb prostheses currently use variable damping to generate the gait cycle. This, however, only dissipates energy. Variable stiffness can store and release energy, making prostheses more efficient for walking. This study aims to design and evaluate a semi-active adjustable stiffness ankle-knee prosthesis that can change its stiffness during a single gait cycle. A Knee-ankle prosthesis that can change its stiffness from a high to low mode in a gait cycle was designed, tested and evaluated. The principle for stiffness change in this design is a leaf spring for which the force application point on the leaf spring moves. The design can move the application point quickly over a length since the rotation of the outer frame is converted into a linear motion of the application point. The stiffness, movement range, power usage and rate of stiffness change were evaluated with different tests. One test is for the stiffness and movement range, and one is for the power usage and stiffness rate of change. The ankle joint’s high and low stiffness modes were 1.4 N m/° and 0.6 N m/° respectively. The movement range for the ankle’s high and low stiffness mode was 0° - 15° and 0° - 20° respectively. The knee joint’s high and low stiffness modes were 2.4 N m/° and 0.2 N m/° respectively. The movement range for the knee’s high and low stiffness mode was 0° - 10° and 0° - 40° respectively. The stiffness is changeable from high to low mode in 0.4s, and the power usage is 9W. The prosthesis did not have a high enough stiffness for both joints. And the movement range of the low stiffness of the knee joint is too low. Nevertheless, the prosthesis has the novel ability to change the stiffness of both joints with only one motor. Furthermore, the linear movement of the force application point through a rotation has also not been done before, making the stiffness change fast. Still, more research and future designs are needed to make the prototype functional as an ankle-knee prosthesis. Nevertheless, the design is a promising first step to designing an efficient semi-active adjustable stiffness ankle-knee prosthesis.

Energy harvesting has gained lots of interest over the past few decades. This study explores the application of energy harvesting in lower limb prosthetic devices. The control system of a lower limb prosthesis includes sensors, wireless
systems and other active components which all require battery power. In order to save some of this battery power, reduce weight, and have the devices have a longer runtime, a form of energy regeneration is desired. Therefore the goal of
this study is to design and experimentally evaluate an energy harvesting system to power the control system of lower limb prostheses. The final prototype is designed following the process of setting up functional requirements, constraints and wishes. This leads to three derived concepts. After an evaluation against performance criteria and an in-depth evaluation concerning the power output, the compliant spring design is chosen to be worked out further and evaluated with a newly designed vibration shaker table. The relevant findings are laid out in the results. From these findings, interpretations and implications are discussed further, concerning advantages and limitations of the energy harvesters and the experiment. Results from the conducted experiment show a peak power output of 25.8 mW at an input amplitude of 12 mm and a frequency of 9 Hz. A power mass ratio of 0.21W/kg is achieved. The design meets the power demand requirements to power microprocessors and sensors of the control system of a lower limb prosthesis and extends runtime with 15.7%. However it is still important to investigate the power requirements for state of the art lower limb prostheses. Furthermore, it is recommended to improve overall efficiency in future studies, compare the results with state of the art energy harvesters based on vibrations, and execute a gait test for further design validation. The results from this study demonstrate comparable data and present the innovations possible in prosthesis design and the advancements in utilizing ambient power sources for energy harvesting. Enhancing the overall efficiency of this design, and promoting comparable results to other designs in the existing literature, could emphasize on the potential of energy harvesting applications.

Background: Lower limb amputations significantly impact an individual’s mobility and quality of life. Passive-elastic prosthetic feet are often prescribed to restore ambulatory functions; however, selecting the correct prosthesis for patients is challenging due to the diverse mechanical properties and designs of commercially available prostheses. Furthermore, prosthetic prescriptions rely heavily on clinical judgment rather than patient feedback. Current alternatives for prosthetic foot trials face logistical and practical limitations.

Objective: This study aims to develop and evaluate a novel ankle prosthesis emulator capable of emulating the mechanical behaviour of multiple commercial passive-elastic prosthetic feet, allowing for rapid back-to-back trials in both clinical and real-world environments.

Methods: The Variable Stiffness Prosthetic Ankle (VSPA) was modified to accommodate a multicam mechanism, allowing the emulation of five different prosthetic feet. Mechanical properties, such as the torque-angle relationship, were characterized for the emulated feet using finite element analysis (FEA) and mechanical testing with a 3D-printed prototype. The FEA predicted results and experimental results were compared with the original commercial prosthetic feet data to validate the emulator.

Results: The FEA predicted torque-angle relationship of the emulated prosthetic feet closely matched the mechanical properties of their corresponding commercial feet, with percentage errors of 2.87% in dorsiflexion and 9.28% in plantarflexion. The torque-angle relationship generated from the 3D-printed multicam mechanism exhibited a similar nature to the experimental data. However, the torque magnitudes were significantly less than the actual prostheses. The switching mechanism of the cam profiles was also successfully demonstrated by the 3D-printed setup.

Conclusion: Based on FEA the novel ankle prosthesis emulator can effectively replicate the mechanical behavior of commercial prosthetic feet, demonstrating its potential as a cost-effective and time-efficient tool for patient trials and prosthesis selection. However, the same needs to be validated based on real-world tests using the manufactured prototype. The 3D-printed multicam mechanism was not able to effectively emulate the commercial feet due to the dissimilarities in material properties of the 3D-printed and proposed components. Future work should focus on manufacturing the mechanism using the proposed materials and optimizing the structure to reduce weight and complexity for long-term clinical applications.

This research addresses the need to ensure the safety and accessibility of roller coasters for people with lower extremity prostheses. Current roller coasters, particularly floorless roller coasters, pose sig- nificant risks to prosthetic leg users due to the intense forces exerted during the ride. These forces may cause the prosthesis to dislodge and eject, leading to accidents and injuries to riders and bystanders. To solve this problem, this research aimed to develop a product that ensures the secure attachment of prosthetic legs that can withstand the dynamic forces of roller coasters while ensuring user comfort, ease of use, and adherence to safety standards.
The methodology involved conducting G-force measurements on roller coasters, interviews with stake- holders, and analysing different prosthetic designs. A risk assessment was performed to identify po- tential hazards associated with the detachment of the prosthesis. The research led to the development of two primary concepts: the SafeStrap and the MeshSafe. These designs were prototyped and eval- uated under real-life conditions using user feedback from prosthetic leg individuals and testing with a dummy.
The SafeStrap, with its compact design and adaptable components, emerged as the most promising solution, offering a practical and user-friendly mechanism to secure prosthetic legs during roller coaster rides. Its ease of manufacturing, compactness, and versatility make it a stronger candidate for further development into a commercial product. Additionally, the SafeStrap can be adapted for use in other extreme sports such as skydiving, further expanding its potential application.
This research advances inclusivity and accessibility in the amusement and leisure industry for people with lower extremity prostheses by introducing the SafeStrap, a reliable and comfortable solution that enhances their safety and experience in amusement parks.

Energy dissipation plays a crucial role in mitigating noise and vibration in a wide range of applications. In the field of assistive devices, energy dissipation is used to improve the stability of joint motion and protect the musculoskeletal system from excessive loads. It is not surprising that considerable effort has gone into developing effective energy dissipation mechanisms for this application. However conventional devices are bulky, expensive, and rigid. They are known to cause discomfort, and skin trauma to the patients. With the advances in soft robotics, novel soft exoskeletons that demonstrate bio-mimetic functionality, increased comfort, and cost-effective designs are being developed. This work proposes a novel soft, passive damper, intended for operation as an energy dissipator in assistive devices. The study begins with an overview of the state of the art in assistive devices, and energy dissipation mechanisms. A comparison is made of the various modes of energy dissipation for the intended application, and the most suitable one is selected. A proof-of-concept passive flexible damper is designed. A prototype is assembled and its working is experimentally verified. The study concludes with the successful demonstration of a novel soft damper, comments on the current limitations, and suggests future research directions to improve on this approach. This work is a contribution to the development of a new class of soft energy dissipators.

In the context of prosthetic devices, the absence of natural sensory feedback poses a significant challenge, leading to limited proprioceptive sensation and reduced control over artificial limbs. This study explores the potential of establishing a magnetic connection between prosthetic devices and muscles to enhance proprioceptive feedback and facilitate more intuitive control of prosthetic limbs. The primary objective is to ascertain the safe range of forces that can be transmitted magnetically from a prosthesis to a muscle, with ethical considerations guiding the allocation of muscle resources.
Preliminary experiments conducted using Silicone Ecoflex 0030, chosen for its stress behaviour similarity to natural muscle tissue, serve as the cornerstone for this research. A novel methodology is introduced to predict the forces generated when magnets snap, particularly when one magnet is embedded within an elastic medium like silicone, replicating the force distribution characteristics of muscle tissue. The theoretical model guiding these predictions is based on empirical data collected from experiments that investigate the magnetic force interactions between magnets and the distinct properties of silicone materials. Validation of the theoretical model for predicting the snapping point is achieved through a comprehensive series of final experiments.
This study demonstrates that the monopole model, tailored for magnets with parallel-aligned poles, yields highly accurate predictions when compared to empirically measured data concerning magnet force modelling. Additionally, within silicone, the force-displacement relationship exhibits linearity, with stiffness primarily contingent on the length of the implanted object. Force transmission experiments involving a magnet embedded in silicone reveal that magnets snap at forces of less than 3 Newtons.
A significant outcome of this research is the development of a validated methodology for predicting the force when a pair of magnet become unstable and snap. This methodology is applicable to scenarios involving magnets embedded in elastic media like silicone and holds the potential for extending predictions to snap forces in muscle tissue. The implications of this study are promising, suggesting the feasibility of employing magnets as sensors to detect muscle intent and as activators to provide feedback by mobilizing implanted magnets, thereby stimulating muscle spindles. These findings open new avenues for enhancing proprioception and control in prosthetic devices.

Spinal cord injury(SCI) is a life-altering event that often leads to wheelchair confinement and a lifetime of secondary health complications. Gait orthoses aim to restore mobility and improve the quality of life for these individuals. However, they are often rejected due to the high energy expenditure required by the individual. This project focuses on the Cloud Walker, a novice reciprocating gait orthosis aiming to make a difference. This project aims to decrease the energy expenditure required to walk with the Cloud Walker, making it more likely to be used by individuals with SCI. It was hypothesized that by changing the locked ankle and knee joint of the original Cloud Walker with a passive knee joint and a stance control knee joint, the energy expenditure would go down and the self-selected speed would go up. Two randomized cross-over experiments validated the modified Cloud Walker. Participants wore both the original and the new orthoses while their metabolic values were being monitored. The results showed a 16.9% decrease in oxygen uptake, 7.1% lower heart rate, 16.5% lower energy consumption per hour, and 17.3% fewer calories burned with the new orthosis. Specifically, the knee joint alone accounted for a 13.0% decrease in oxygen uptake, 5.3% lower heart rate, 13.03% lower energy uptake, and 16.7% reduction in calorie expenditure. The self-selected walking speed increased by 30%, however this was not statistically significant. Overall the new version of the Cloud Walker showed to be a significant improvement to the original and is a step closer to helping people with spinal cord injury.

Background: Through technological development, a variety of mechanical finger joints have been produced. No current design takes inspiration from nature enough to develop a synovial inspired single finger joint. Due to this the potential performance is unknown, while natural joints out perform mechanical finger joints with respects to the coefficient of friction.

Goal & Research question: The goal is to construct a novel 3D printed 1-DOF mechanical synovial proximal interphalangeal(PIP) joint to explore the parameters of influence. In the exploration of these parameters, the following research question is formulated: To what extend does each of the following variables effect the coefficient of friction, the joint stiffness and hysteresis of a synovial joint? In which the material selection, contact surface roughness, capsule influence and fluid selection is considered.

Methods: Design requirements and performance criteria were formulated to guide the design process, from which the final design was generated. The design was measured with an optical profilometer to determine the surface quality and the performance evaluated with a custom build friction test bench.

Results: Through the process of this paper, a novel 1-DOF mechanical synovial joint was designed with a range of motion of 100 degree, along with a proof of concept design with 100 degrees in flexion and 8 degree in hyperextension. The synovial joint was successfully tested to access the performance and evaluate to which extend each of the parameters stated in the research question effected the performance.

Conclusion: The joint was successfully produced and allowed for evaluation of the desired parameters. Overall, the contact surface material and the contact surface roughness are the main contributors to the performance of the joint. The capsule has mixed influence while the lubrication shows some improvement with coated low roughness samples over the dry friction conditions. For all other cases the dry sliding baseline joints outperform the encapsulated lubricated joints.

Automation within an industrial sector has now for years been an obvious factor. Everywhere mechanical instruments and sensors are implemented for fast and precise processes. The agricultural sector is some steps behind in relation to other sectors. Reason being that there are many irregularities which in other sectors have been made into uniform variables. One of the problems that needs to be tackled within the agricultural sector is having the leaves of crops removed.
Rijk Zwaan has created a new variety of broccoli and to make this commercially viable, a harvest machine is required. One of the aspects of this harvesting process is removing the leaves. This has to be achieved in one continuous session, with at least a ground speed of 1 km/h, while the broccoli's are still in the field. With a focus on the best performance for the least destructive working principle. After listing all the requirements, ideas are structured in a morphological overview. A weighted criteria table will be used to select three ideas, which will be made into prototypes.
Results from the initial testing period will reveal the best concept, which will be optimised. This was the Metal Wire design, which exist of multiple stainless steel wires attached perpendicular to a rotating shaft. An important aspect that boosted the performance was the unravelled ends of these wires. These rotating shaft had the wires removing the leaves, while beating the leaves down from both sides.
After optimization, the current prototype could ensure a 60% of the top section and 80% of the middle section with 20% of the broccoli’s destroyed. Which was not enough to satisfy the goal, however the promising results could be improved with an upgraded machine. A clear trade-off was found between the performance and destruction. Significant improvements in results could be achieved by incorporating additional features such as a funnel and designing a more robust structure with fewer obstructions, controllable ground/rotational speed, and better alignment with the beds. Therefore at the current state the leaf removal machine operates substandard, but has potential to be developed into the desired product.

Immobilisation devices are commonly used for the treatment of extra-articular distal radius fractures. However, conventional immobilisation devices such as plaster casts and fibreglass casts may lead to complications and discomfort. Another disadvantage of present-day conservative fracture treatment is that the casts have to be replaced after one or two weeks when the swelling subsides. In this thesis, an alternative distal radius fracture treatment device was designed, prototyped and evaluated. The main goal of this design was to make the immobilisation device adaptable to swelling while fitting most patients.

The device was designed using a three-step iterative design process and four successive iterations. The steps that were performed in each iteration were setting the requirements, generating solutions and evaluating and deciding. The development of the design was done in the following steps: generating design directions, developing a conceptual design, embodiment of the design and detailing the design. A prototype of the device was created to demonstrate the device's functionality. The design and the prototype were evaluated using diverse methods. Ten healthy volunteers provided feedback after wearing the device, an orthopaedic surgeon offered his expert opinion and several aspects were assessed using calculations and literature. After the prototype was made and evaluated with healthy participants an additional iteration was done to improve the function of the design.

In the first stage, 16 design directions were generated, and the three most promising design directions, the Cushioned Clamp, the Filled Sleeve and the Friction Slots were selected. In the next stage, these design directions were further developed into conceptual designs. The Cushioned Clamp was chosen as the best solution. The Cushioned Clamp consists of interconnected rings around the forearm, wrist and hand with pads that can be adapted in height. In the next step, an embodied design was made. This design had a large offset on the arm and therefore the rings were made adjustable during the detailing phase. Also, the usability of the device was improved. The final design is a device with three adjustable rings with pads that can separately be adjusted for swelling of the limb. The rings are connected with telescopic mechanisms. With a few additional size parts, the single immobilisation device can be adapted to fit 90\% of the adult population. The device was prototyped using aluminium, SLA-printed Form Tough 1500 and Draft Resin, FDM-printed PLA and foam. The prototype allowed too much movement of the wrist, this was addressed and solved after the tests with healthy volunteers. The device is reusable, which reduces waste as less material is used and disposed of. Furthermore, the device is waterproof which reduces skin complications and improves hygiene. The device allows thumb movement which improves the hand function. Furthermore, the mass of the device is 437~grams, which is less than a conventional plaster cast. Volunteers were generally satisfied with the device and the device is quick in application. The medical experts shared concerns about comfort, robustness and applicability for different fracture types. During the improvement phase, several aspects of the device were discussed and improvements were made. Most importantly, additional telescopic mechanisms and connections were designed to prevent movement in the device. Further, the comfort, X-ray permeability and play in the prototype were addressed.

The device is adjustable and adaptable to swelling while allowing skin ventilation. Further, good hand function, a sustainable design and clean applications are advantages of this design. However, the functionality of the design and the prototype can be improved by reducing play and improving robustness. Furthermore, the comfort of the device can be increased by making the device more compact and distributing the pressure better.