Background
An upper limb amputee currently has two choices for a body-powered prosthesis, a Voluntary Opening (VO) or Voluntary Closing (VC) hand prosthesis. Which type is best, depends on the task and the individual. Currently, there are no good options for VO and VC in one design.
Objectives
To design a proof-of-principle of a hand prosthesis and to validate the feasibility of the prosthesis. The hand prosthesis must have two different modes, the VO mode and the VC mode. Changing between these modes can be done without using the other hand..
Methods
First, a list of requirements and wishes was made, where cable forces are important because too much cable force can cause discomfort, fatigue or make the prosthesis difficult to control.
A new design was created and a prototype was built for user testing. SHAP was used as the outcome measure.
Results
The prototype allowed the user to change between VO and VC and SHAP showed promising Linear Index of Functionality (LIF) values. The calculated cable forces were mostly within the requirements. However, because the prototype of this design was produced with an FDM-printer, not all the tests could be done and the calculated forces could not be verified.
Conclusions
A prototype of a hybrid hand prosthesis with VO and VC modes showed promise, with positive test results. However, limitations in the prototype's construction hindered some tests. The calculated cable forces mostly met requirements, except for a slightly high pinch grip force. Further development is needed, and there are material and design recommendations. This concept demonstrates feasibility but requires more work to become a functional hand prosthesis.

Goal: Nerve injury is a typical complication of a fasciectomy, a surgical treatment for Dupuytren's contracture. This research focuses on the creation of a surgical device to prevent this medical complication.
Design: A mechanical feedforward-based device with a spreading and cutting mechanism was proposed. Stretching the target tissue causes a larger biomechanical difference between this tissue and the nerves. This helps to avoid damaging the nerves during the dissection phase. The DisDis prototype with a precision handling grip was develop. It uses a nitinol tube for the spreading mechanism and a conventional scalpel for the cutting mechanism.
Evaluation: The performance and ergonomics of the prototype are disappointing, compared to the conventional fasciectomy dissection method. Despite this unfavourable result, it is thought that mechanical feedforward-based devices could be still make a positive impact.

Background: Scoliosis is a three-dimensional abnormal curvature of the spine, with Adolescent Idiopathic Scoliosis (AIS) being the most common type. Current fusion treatment is highly invasive and removes all mobility of the fused spinal segments. To tackle this problem, non-fusion techniques were developed, that try to correct the abnormal spinal curvature while maintaining healthy spinal mobility. The state of the art of non-fusion treatment includes techniques that have highly inefficient methods of correction, contain long and hefty structures leading to large surgical scars, or cause the need for revision surgery. Most importantly though, all of the current techniques have high complication rates. It was therefore deemed necessary to design a mechanism that facilitates minimal invasive and local, non-fusion correction in a mechanically effective way, by applying constant force in the appropriate direction.

Methods: The anatomy and mechanics of a thoracic spinal segment were analyzed, showing the challenges that are at hand. From there, lists of requirements and wishes were generated that initiated the conceptualization process. Concepts were then generated, categorized, and selected after which it was shown that the concept of a single buckled leaf spring with joints was the most suitable. Future vision figures were made showing how an implant could look like that contains this mechanism. The mechanism was then further developed and an experimental setup was designed and built. This setup was used to carry out four proof of principle experiments that examined the viability of the buckled leaf spring as functional mechanism. The relation between thickness and buckling force was tested, as well as the hysteresis of the mechanism. Furthermore, the effect of misaligning
the mechanism both translationally and rotationally has been examined. Finally, the mechanism was placed inside soft tissue phantoms to examine the effect of the presence of surrounding soft tissues.

Results: A buckled leaf spring that fits the size and material requirements was manufactured and the results of the proof of principle experiments show that it manages to create a constant buckling force of desired magnitude for correction. However, misaligning the implant did show effects on the force profile, with the effects of translational misalignment being the most significant. Finally, little hysteresis was perceived, which significantly increased when the leaf spring was placed within a soft tissue phantom.

Discussion and Conclusion: The mechanism is as of yet not suitable for clinical implementation. Further design steps must be conducted and an extensive analysis of the anatomical and mechanical effects of placing the implant against the spinous processes must be carried out. Further recommendations have been made to improve the design and functioning of the mechanism. This study has demonstrated the potential that the mechanism of a buckled leaf spring has in the constant force correction of scoliosis.

Post-mortem interval estimation (PMI) is a key part of forensic investigation. Accurately obtaining a PMI early in the investigative process improves the reconstruction of events, directs follow-up research and narrows down suspects in case of homicide. Currently, PMI is determined using Henssge’s nomogram requiring ambient temperature, rectal temperature, an estimated body weight and an estimated correcting factor to account for the clothing of the deceased. These body weight and correcting factor estimates are subjective and can lead to errors of up to 14 hours from the actual PMI.
To improve the accuracy of the PMI Academic Medical Centre (AMC) in Amsterdam, TU Delft, the Dutch Forensic Institute and the Dutch police initiated the Therminus project. Using the Wilks Model [1]with specialised equipment can increase the accuracy of the PMI by up to a 15-minute margin of error under ideal circumstances and up to 3.2 hours under non-ideal circumstances.
For the Wilks model, the weight of the deceased remains an important input and the QuickScale was developed as a specialised tool to provide this information to forensic investigators at the crime scene. This report contains the development of the second iteration of the QuickScale, the QuickScale 2.0. Objectives of this development were:
1. To Finish the QuickScale prototype, design the modules needed for building in the electronics and for adding user-friendly, intuitive controls.
2. To design and conduct usability studies with forensic investigators and use the obtained information to further improve the QuickScale construction, electronics and usability.
Using a design analysis and usability engineering approach for the QuickScale design and user interface respectively. The QuickScale design was calibrated, and validated and possible improvements were identified. Three different user interfaces were developed and usability studies were conducted for groups of students and forensic investigators. New design requirements were derived from both the design analysis and usability studies.
The resulting QuickScale 2.0 design incorporated the user interface that resulted in the least user errors. It met 27 out of the total 30 design criteria and contains:
• An ambidextrous user interface.
• Correcting springs for the non-linearity of the load cell when measuring weights below 20kg.
• Handlebars with improved grip which can easily be extended to accommodate more users.
• Safety labels with an abbreviated guide on the field use and stickers indicating the controls

The un-met design criteria were an indicator of remaining battery life and the possibility that both units can display a difference in weight larger than 0.5 kgs, especially at the start of weight measurements. As this design still needs to be produced, it needs to be tested and evaluated. Special care should be taken when calibrating the QuickScale 2.0 and altering the calibrating method might be necessary. Furthermore, it is recommended to integrate the QuickScale 2.0 with other Therminus equipment in future evaluations.

All in all the QuickScale 2.0 is a user-oriented step toward more accurate post-mortem interval estimation.

Introduction - Grasping unknown objects is an important ability for robots in logistic environments. While humans have an excellent understanding of how to grasp objects because of their visual perception and understanding of the 3D world, robotic grasping is still a challenge. Due to the fast-growing development of deep learning methods, it is now possible to train deep neural networks on this grasp task.

Objective - This thesis proposes a bin-picking pipeline that uses deep learning to take care of the perception and estimation task. The pipeline can predict grasps for known and unknown objects with a two-fingered pinch-gripper in real-world environments in a single object and multi-object scenes.

Method - A grasp annotation tool has been developed to generate a wide variety of grasps in the training data that are antipodal and collision-free. Together with annotated objects, the generated grasps are used to train Grasp-RCNN. The developed Grasp-RCNN combines an object- and a grasp-detection network to predict objects masks and grasps, and a decision algorithm that picks the best-estimated grasp based on a grasp score.

Results - Robotic experiments demonstrate that the proposed method allows a robot gripper to grasp both known and unknown objects in single-object and multi-object scenes with a total success-rate of 89.7% and 81.0% with average process-times of 616 ms and 739 ms per scene respectively. In a bin-picking scene a success-rate of 87.5% with a process-time of 1235 ms is achieved.

Conclusion - These results indicate that the proposed Grasp-RCNN is able to grasp known and unknown objects with an accuracy that is comparable to the state-of-the-art. For production purposes, the speed of the network still can be improved.

Fruit and vegetable production is increasing worldwide, and farmers currently face a tough challenge in finding enough agricultural workers. Automation of the labour-intensive task of crop harvesting could help fill in this gap between supply and demand. However, picking soft fruits is challenging, as they can be easily damaged if not carefully handled. This paper focuses on designing and evaluating a novel robotic gripper for gently harvesting blackberries, which is nicknamed the Twisting-Tube gripper. The gripper consists of a fabric tube which closes in an enveloping manner due to a motorized twisting action of the ends of the tube. A custom tensile-testing bench was used to test blackberry detachment, release, and damage rates for three types of tubes: radially elastic, fully elastic, and compressible. These tubes were manufactured out of different combinations of foam padding, spandex and food-safe cotton cheesecloth and compared to a handpicked control. The results showed that compressible, thicker cheesecloth outperformed radially elastic or fully elastic or extremely compressible tubes with 82% successful detachment and 95% successful release rates. Furthermore, the Twisting-Tube gripper with thick cheesecloth discoloured at least one drupelet of 19% of the blackberries after 48 hours, which is less than the 33% measured in the handpicked control group, but still more than the 10% of the unhandled berries with discolouration. Moreover, the gripper with thick cheesecloth caused leakage to at least one drupelet for 29% of the successfully harvested blackberries compared to 13% of the hand-harvested control. It can be concluded that the presented Twisting-Tube gripper prototype shows promising results for harvesting small soft fruits.

There is an increasing need for transfemoral prostheses that provide gait support, stability, safety and comfort. Although there are many prostheses available in different levels of complexity and price, there is still room for improvement. It has been proved that the cost of transport (CoT) for walking is significantly increased for transfemoral amputees with respect to their healthy peers. Assisting push-off is one of the main challenges in prosthesis design. Push-off is normally achieved by plantarflexion of the ankle joint. Prosthesis designs should aim to restore this function in order to lower the amount of energy needed for walking.

This study aims to investigate the effect of prosthesis design on the gait pattern through musculoskeletal modelling and predictive simulations. Two prosthesis designs are modelled for these purposes, after which several variations on these models are made. It is hypothesised that the prosthesis that assists in push-off through ankle plantarflexion, should result in a gait pattern that is closer to a healthy one. It should also decrease the CoT. Furthermore, we aim to evaluate the use of modelling and simulations in the customisation of prostheses.

OpenSim was used to create a total of eight models based on a model with 9 degrees of freedom and 18 muscles: a healthy person, a conventional prosthesis model, two scaled versions of the conventional prosthesis model, the walkMECH prosthesis and three variations on the walkMECH. SCONE was used to find an optimal gait pattern for each of the models through the CMA-ES method. CoT-, gait-, degrees of freedom- and reaction force objectives were minimised. The results were evaluated by comparing the CoT, joint angles, ground reaction forces and muscle activation of each model.

The CoT for the healthy model was found to be higher than reported before, based on both experimental and simulation studies. As a result, we have little confidence in the CoT estimation of our models. This is further exacerbated by the finding of a lower CoT for the conventional prosthesis than for the healthy model, in contrast to earlier reports. The results for most other measures were irregular, making it difficult to draw conclusions from them. It is expected that the predictive optimisations did not reach a global minimum, and that the results are therefore not accurate. Future research should aim to solve this problem. It should also be attempted to find the cause of the difference in CoT between our simulations and those of others.

No conclusions could be drawn from the results. Nonetheless, there is a clear potential for the use of musculoskeletal modelling and predictive simulation in the investigation of the effects of prosthesis design on gait.

Fluid-controlled actuators are widely used in lower limb prostheses. Most fluid-controlled actuators have valves integrated into the cylinder systems and require complex manufacturing steps, making these systems expensive. A cost-effective production method for these complex actuator valve systems is 3D-printing. The goal of this research is to study the possibility of creating a pneumatic and hydraulic cylinder with integrated valves using 3D-printing and evaluate their performance. A 3D-printed pneumatic cylinder with integrated valves was designed, manufactured and tested on static and dynamic leakage for different pressure levels on a designed test rig. To evaluate the performance, the leakage data was compared with the performance of a commercial pneumatic cylinder. A 3D-printed hydraulic cylinder was designed and built according to the earlier design insights. The 3D-printed hydraulic cylinder was tested on hysteresis and internal and external leakage in open and closed valve mode. Overall the commercial pneumatic cylinder performs better on static and dynamic leakage. In static leakage, a maximum pressure loss of 0.0095 MPa was measured at 0.6 MPa starting pressure after 20 minutes in the 3D-printed pneumatic cylinder. In dynamic leakage tests, a larger pressure difference of 0.035 MPa is measured at 0.5 MPa after 20 minutes in the 3Dprinted cylinder. The higher leakage profiles of the 3D-printed cylinder are caused by a difference in roughness and clearance of the sealing seatings causing movement of the seals. The 3D-printed hydraulic cylinder did not work as expected with 20 N force for moving the cylinder over its stroke, internal leakage of 0.007 MPa at a 0.01 MPa dynamic test and an average external leakage of 8.7 mL after 20 minutes. The tests gave important insights into sealing selection, which was not optimal for the hydraulic application. All in all, this study shows that it is possible to create functional 3D-printed pneumatic cylinders for static applications. Thereby it gives important design insights into improving the performance of 3D-printed pneumatic cylinders for dynamic applications and 3D-printed hydraulic cylinders.

A common method to investigate multisensory integration is using multisensory illusions. The rubber hand illusion is one of the best-known multisensory illusion used in clinical applications. By stroking a visible rubber hand and the participant’s occluded hand, the illusion arises that the rubber hand belongs to the participant. Possible applications based on this illusion are for neurorehabilitation or developing robotic devices. These applications are still in a very initial state, and this thesis aims to take these possible applications a step further. The thesis provides the results of a rubber hand illusion experiment over time and a dynamic model related to the embodiment of the rubber hand. The dynamical model can visualize the proprioceptive drift that arises from the illusion and predict the time it takes to experience it. The results of the experiment and other empirical findings from the literature form the basis of the model. The experiment measured these factors and the feeling of ownership and agency over time. The results from this experiment have much variance but are in line with the literature. The dynamical model fails to visualize the body ownership and agency results. Adding extensions and improvements could make this dynamic model more complete and applicable in many research fields.

Duchenne Muscular Dystrophy (DMD) patients suffer from a severe form of progressive muscular weakness. Consequently, as the disease progresses these patients become more and more dependent on assistive devices for their daily activities. For instance lifting their arms against gravity already becomes challenging. So far, a considerable amount of effort has been put in the development of assistive devices. However, compensating the weight of the hand remains challenging as the required balancing torques are dependent on the position of the hand and the orientation of the forearm.

In this research a solution is proposed to passively compensate the weight of the hand by making use of a simplified torque profile (a constant torque). The effectiveness of this profile was assessed experimentally in a group of healthy subjects. For this the wrist muscle activity required to lift the hand against gravity was measured through surface electromyography, for several types of compensation. From this experiment the conclusion can be drawn that a constant torque profile performs similar to the theoretically ideal type of balancing, showing a similar reduction in the anti-gravity muscle activity.

Based on these findings, a mechanism has been developed capable of providing an adjustable constant force, by making use of a combination of positive and negative stiffness springs, for implementation in a wrist support for DMD patients.

Background: Current challenges in the design of anthropomorphic robot fingers is the implementing of anatomically accurate tendon-ligament structures, specifically for the collateral ligaments, volar plates, and the extensor apparatus. The development of robot fingers with these structures could aid in the further understanding of the functional anatomy and biomechanics of the human finger. It has been suggested that these fibrous structures can be emulated as a set of individual, non-elastic strings. The configuration of these tendon-ligament structures result in the specific motions of the finger.
Aims: The aims of this thesis were to develop and manufacture an anthropomorphic finger prototype with fully anthropomorphic tendon-ligament systems. So the prototype could be functionally actuated as a human finger, and would perform humanoid motion mechanisms, such as the Interphalangeal joint
coupling, an ab-adduction/axial rotation coupling.
Methods: A parametric finger model was derived from CT images of human finger bones, with a focus on the soft tissue connection to the joints and the tendon pulley system attached to the phalanges. The finger segments were designed as a shell structures with functionally anthropomorphic shapes. The finger contained the metacarpal bone, the proximal, middle and distal phalanx and included
humanoid joints, tendons, and ligaments. These finger bone shells had fine rosters of perforations for the attachment of joint ligaments and supporting ligaments, implemented as a collection of individually attached dyneema strings, allowing for the precise and iterative attachment of these strings. The strings
had adjustment possibilities to accurately determine their functional lengths. This model was then produces by FDM additive manufacturing on a scale of 5:1 with PLA as a material. To reduce the friction around the joints, friction experiments were performed, where graphite in an epoxy resin was found to be an appropriate coating for the joint surfaces. The tendons and ligaments systems were developed as a collection of non-elastic Dyneema strings, where the string lengths and positioning were identified according to biomechanical finger models.
Results: The result was the creation of a finger prototype with anthropomorphically realistic pulley systems for the tendons with joint surfaces of minimal friction, so that the finger could be actuated by the tendons to simulate realistic humanoid behaviour. The humanoid motion, and coupling mechanisms
were verified with 2D motion tracking software and manual measurements by performing possible
movements done by actuating the muscle tendons of the finger prototype and by comparing the resulting
motion with that of a human finger. Where the finger prototype performed similar motions as a human finger.
Conclusions: This research project successfully developed an anthropomorphic finger with humanoid joint-ligament systems connecting the finger segments, and tendon configurations. It showed the possibility of constructing these systems and configurations as a set of individual strings that could emulate the structures found in the human body. The resulting anthropomorphic finger can form a
basis for further research in the complex mechanics, relation, and dependencies of the human hand and in doing so, aid in the study of a wide range of pathologies in the finger and the hand, as well as support surgeons in reconstructive surgery and rehabilitation.

Introduction: Amputees may be eligible to use a socket or osseointegrated (OI) prosthesis after losing a limb. A lot is known about the stump-socket interface in transtibial (TT) amputees. However, there are hardly any articles that explain the load transfers between the tibia and an OI prosthesis. For this reason, this study will focus on the load pattern at the bone-implant interface. The aim is to investigate how the osseointegrated loading for TT amputees is compared to able-bodied subjects. Method: Two generic musculoskeletal models were created in OpenSim: a transtibial osseointegrated (TTO) model and an able-bodied model. The able-bodied model includes all muscles in the lower limb, where the TTO model had no muscles around the tibia. Two datasets, consisting of five able-bodied participants (healthy control (HC)) and five transtibial amputees (TTA) with a socket prosthesis, were used. The internal reaction forces and moments were analysed for the affected side during the stance phase of the gait cycle. These normalized forces and moments were expressed in bodyweight (BW) and bodyweight x height (BWH), respectively. Results: The largest forces at the bone-implant interface were measured in the longitudinal direction (-6.92 BW) for the able-bodied model, the lowest in the mediolateral direction (-0.09 BW) for the TTO model. The loading differences were the highest between the able-bodied model and the TTO model with TTA data. Around the antero-posterior axis, the largest moments were found. The able-bodied model measured 0.027 BWH, where the TTO model with HC data found 0.023 BWH and 0.017 BWH for the TTA data. Conclusion: Transtibial amputees have decreased loading at the bone-implant interface compared to able-bodied subjects. The muscles play the most prominent role in comparison with the gait pattern.

According to the World Health Organization 40 million amputees are living in developing countries1. An amputation has a great impact on the quality of life of a patient. In general, patients have limited mobility, often lack of confidence and consequently are at times excluded from participating in society2. Prosthetic rehabilitation could help to overcome these obstacles. However, only 5–15% of the amputees in developing countries have access to a prosthesis. Patients are often not able to afford a prosthesis and facilities are not in immediate vicinity

Two major challenges in the field of agriculture are the need for increases in food production due to the ever-increasing world population and simultaneously climate change caused by global warming. The increasing world population requires more food, and the food needs to be of a higher standard. Currently, the increase and high quality food production by farming are becoming difficult due to more inconsistency of the climate. Plant breed companies use old-fashioned science in their attempts to overcome the agriculture challenges. For plant breeding, multiple plants are combined to develop a plant crop with desired characteristics that can withstand to the environmental challenges, produce high quality crops and provide the production volumes according to the required specifications. If such a crop is developed using breeding, a batch of plant seeds will be produced to sell the plant seeds all over the world. Two main problems do come from breeding and production of these newly developed crops, firstly breeders need information about the plants for efficient plant breeding, and secondly, the quality of the produced plant seeds has to be ensured. The quality of the plant seeds is an important factor to sell the produced plant seeds over the world to growers and farmers. To ensure the quality of the seeds, phenotype experts obtain the information and perform quality assessments of the seeds and grown plants. To obtain information on plants, the experts use plant phenotyping in which the characteristics of the plant are described and evaluated. The evaluation of the plant characteristics provides a quality assessment of the batch of produced plant seeds. The quality assessment is done by growing the plant seed to seedlings and compare the grown seedlings with each other. The visual comparison between the seedlings is used to give a quality label to the produced batch of seeds. At the moment this visualization and subjective comparison of seedlings is the state of the art. Experts did not believe it is possible to assess the seedlings otherwise. To move away from the subjective approach, Rijk Zwaan BV is looking into more objective measurement systems to obtain plant information. The objective plant information of the seedlings provides solutions of objectively assessing quality and inform plant breeders with extra information making the plant breeding process more efficient. In this study, the feasibility of a digital phenotyping system able to give plant information and a quality assessment of the seedlings was examined. To show the possibilities of the system a model of a digital seedling quality system was developed. By applying the literature of plant phenotyping systems, a phenotype and quality assessment data pipeline were established. The data pipeline was developed to be understandable and transparent for the experts to ensure acceptance of a digital system. The plant phenotype pipeline consists out of multiple components. Each component of the plant phenotype data pipeline has been developed to form the seedling quality system model. The developed model is called SeeQS (Seedling Quality System) and is able to seek out the quality of the seedlings and provide phenotype information of the seedlings. SeeQS was evaluated using multiple samples of pepper seedlings to show the performance and capabilities of a digital phenotyping-based quality system. The system performance shows to be very capable and accurate to assess the quality of seedlings and give plant measurements. The model shows that it is possible to assess the quality of seedlings using a digital phenotyping-based system. Due to the transparency of the developed model, the experts understand the versatility of the digital system. Now, the phenotype experts accept the possibility of a digital system to obtain plant information and give a quality assessment. Due to these positive results, the company wants to continue with the development and implementation of a digital seedling quality and phenotyping system.

Various neuromuscular disorders such as spinal cord injury, Charcot-Marie-Tooth disease and poliomyelitis lead to calf muscle weakness, which limits the patient's ability to propel their body forward during gait. Their abnormal gait pattern is characterized by increased ankle dorsiflexion, excessive knee flexion during stance and reduced ankle push-off power which leads to decreased walking speed and increased energy cost of gait. To improve walking ability, dorsal leaf spring (DLS) ankle-foot orthoses (AFOs) are often worn that provide stiffness around the ankle joint which is its most important characteristic. Selecting optimal AFO stiffness is important because it can substantially reduce the net metabolic cost of gait, while improper AFO stiffness can lead to discomfort, fatigue and overall reduced activity. Experimental data shows that the effect of AFOs is dependent on the individual characteristics of the patients, such as level of muscle weakness, spasticity and body mass. Despite the importance of AFO stiffness, empirically determining the stiffness of the applied AFO remains time-consuming and ad hoc. This master thesis aims to uncover the mechanism relating AFO stiffness to the metabolic cost of transport (CoT) as observed in experimental trends from individuals with calf muscle weakness. We used predictive forward musculoskeletal simulations to reproduce the experimental trends and analyzed our simulations to explain the relationship between AFO stiffness and metabolic CoT. The predicted optimal AFO stiffness was within 1 Nm/deg of the patient's experimentally measured one. From the experimentally observed effects, all kinematic and kinetic trends were predicted within 0.5-2.5 SD from the mean of the experimental slopes of all patients' results. Moreover, the differences between the slopes of the simulation results were mostly lower compared to the modelled patient's individual experimental slopes than compared to the experimental slope of the group average results. We identified a reduction in the vasti muscle metabolic cost due to larger external knee extension moments with increasing AFO stiffness as the main mechanism resulting in the net metabolic CoT trend. Limitations on translating our findings to patient behavior include: modelled calf muscle strength, where the model may be significantly stronger or weaker than the patient, and the relative importance of metabolic cost minimization to other goals during walking, such as minimizing the loading rate at heel strike.

The detachment of a product from a suction cup gripper is a challenge that emerged in recent years in the high-speed case packing of packaged food. In this industry suction cups are used to temporarily attach a product to a case packing robot. The detachment of products from the suction cup gripper threatens throughput. In, some cases, the industry notes robots to operate at only 40 picks per minute. This is 30 % of their maximum throughput.
This study aims to gain a better understanding of the dynamic grasping strength
of suction cups. This was done by reviewing the state-of-the-art from industry and state-of-the-practice from literature. It was found that suction cups are the best overall gripper class, and that actuation time poses the main limiting factor for other grippers to perform well in this industry.
Secondly, a six-axis force moment sensor that passes airflow for gripper actuation and without limiting the pull-out load measurement performance was designed, fabricated, and validated. With the current sensor technology, the vacuum hose must be placed over the sensor, leading to the generation of parasitic loads. Passing the airflow through the senor structure is essential to eliminate loads otherwise induced by the stiff vacuum hose. The sensor was designed using strain gauges and a Maltese cross sensor structure. Finite Element Modeling and optimization using sequential quadratic programming was used to determine the dimensions of the sensor. The sensor validation showed a maximum measurement error of 8% in the z direction.
Lastly, with the validated sensor, the dynamic grasping strength of compliant and stiff suction cups was measured using motion paths and products that are typically seen in the packaged food industry. For both the stiff and compliant suction cups, the moment around the axis perpendicular to the plane of motion showed to be a leading factor in detachment of a product from a suction cup gripper. The failure of stiff suction cups is explained by impulse loading, this results in peaks in the load in the force in horizontal direction and the moment perpendicular to the plane of motion. For the compliant suction cups, the detachment was found to be caused by accelerating downwards while the product was not in the center of the gripper. These results have led to the recommendation of two gripper designs. The first, is a suction cup-underactuated hybrid gripper. The second design intently provides rotation freedom to reduce the moment loading on the suction cup. The second design
requires input-shaping to reduce the vibrations at the end of the motion cycle.

Background
Elephants that wander onto the fields of farmers in Myanmar are being shot with makeshift guns. By doing this, the farmers are able to make these animals leave the area without killing them. This results in elephants walking around with bullets inside their body and wounds that need to be looked after. Traditional methods for bullet removal are not allowed in Myanmar as the government does not allow surgery on these government-owned animals.
Method
A set of requirements was determined based on a case research provided by a veterinarian. It was determined that a gripper needed to be designed that is able to reach down a 1 m deep fistula with a diameter of 8 mm. The gripper has to be able to provide visual assistance and rinse the fistula during the procedure. The focus of this research was placed on the gripper head, as there are already flexible and steerable shafts designed. The best gripper was to be determined by a pulling test where the maximum pulling force was measured. Another important requirement was the versatility of the gripper. The shape and size are not 100\% certain so the gripper must be able to grasp multiple bullet shapes. \newline Results The important requirements were met in the final design. For the test phase, multiple prototypes were made with slight alterations in the design. Force measurements determined a higher pulling force on an 8 mm spherical bullet with 4 arms (Median= 16.59 N, IQR= 4.7) than with 3 arms (Median= 13.07 N, IQR= 2.3). The pulling force on that bullet was highest with a tip length of 3 mm (Median= 17.49 N, IQR= 2.9). The final design was used in a gelatin 'phantom' to show its usefulness in a more realistic setting. The gripper was able to remove the bullet five out of five times.
Conclusion
The 4 armed 3 mm tipped gripper is able to travel through the bullet wound without creating new holes and able to grasp and retract from the wound with the dexterity of a veterinarian.

The flash visual evoked potential (FVEP) is an electrical potential recorded with electroencephalogram (EEG) at the occipital cortex. Current FVEP assessment may be elaborated with the acquisition of stimulus response (SR) relation of the visual system. A drawback of this adjustment is the time required for data acquisition. This study aimed to develop an optimal (rapid) stimulus paradigm for assessing the SR relationship using FVEP.SR relationships were obtained using two different protocols in eight healthy participants; one considered 100 stimuli for 10 different intensity levels (standard technique), the other considered 1000 stimuli of varying intensity levels within a fixed intensity range (novel technique). Hypothetically the novel technique produces a similar SR relationship but requiring reduced number of stimuli. However, the present study did not find a significant intensity dependency on the FVEP. Consequently, no mathematical model for the SR relation was fit to the data, and exploration of the novel technique was excluded. Instead, the present study investigated the minimal number of stimuli required to acquire a representative FVEP component. Secondly, the potential change of FVEP components during the experiment was investigated. This study demonstrates that it is possible to acquire a reliable FVEP component with on average 54 stimuli (gross mean (39) + 1 SD (14)), independent of stimulus intensity. Additionally, this study demonstrated that the FVEP components change significantly (p<0.05) for most stimulus intensities when 1000 or more flashes are used; amplitudes increased with time for low intensity stimulation, while amplitudes reduced with time for high intensity stimulation. Although the present study did not find an intensity dependency of the FVEP component, it demonstrated that stimulation time is an important parameter when acquiring SR relationships using FVEP. The stimulation time certainly influenced the SR relationship calculated in the present study. Further studies can and should reduce the number of stimuli to produce a representative SR relationship using FVEP.

Problem: Due to high rejection rates regarding prostheses’ use, the assessment of the amputee’s use of the prosthesis has become more critical. Today’s prosthesis research is limited to assessing a users’ performance to perform tasks in a controlled environment. Therefore, these studies cannot wholly assess how the prosthesis is used in the daily lives of amputees. Purpose: The purpose of this thesis project is to create, test, and examine the performance of methods that can be used to enhance prostheses' research and evaluation. Results: We have created several enhancements and extensions regarding prosthesis research and evaluation for three sensor scenarios. In the first scenario, we only use an accelerometer, which allowed us to create a new method for creating a vector magnitude (VM) that can show us what type of arm movement is made; additionally, we created a novel scoring system to determine the intensity of movements that are performed. In our second scenario, we used an additional gyroscope, which opened up possibilities for using more advanced Sensor Fusion (SF) techniques. We created an accurate tilt estimation algorithm that remains robust against high levels of gyroscope noise, accelerometer outliers, and measurement model violations. With the gyroscope, we were also able to create a VM from rotational velocity, which displays information about the arms’ rotational movement. Additionally, we created a novel scoring system that also shows the intensity of the performed movements. Our last scenario considers the use of two Inertial Measurement Units (IMUs); we present a novel algorithm for estimating the relative sensor orientation. This algorithm uses a joint kinematic estimation method that incorporates the connection between adjacent segments within a SF algorithm that remains accurate in the vicinity of common real-world disturbances, among which are; high levels of gyroscope noise, accelerometer outliers, and Soft-Tissue-Artifacts (STA). Conclusion: The best way to enhance the analysis for prostheses research and evaluation is to start incorporating gyroscopes into the research process. This can either be in the form of the single sensor case or the double sensor system. The additional gyroscope(s) will enable the use the SF techniques and methods as discussed in this report.

The muscles around the ankle (calf and dorsal flexors) are essential for performing activities in daily life, like walking. Neurological and muscular pathologies, such as stroke, cerebral palsy, spinal cord injury, muscle atrophy and post-polio syndrome, affect the ability of voluntary muscle control and/or muscle strength of such muscles. This severely impairs the gait function of many people worldwide. An ankle-foot orthosis (AFO) or ankle brace, which is an assistive device that provides support to the ankle and foot, are in many cases a solution. Therefore, patients are fitted with an AFO to promote a functional gait pattern. To optimize the resulting gait pattern, the mechanical characteristics of the AFO should be matched to the specific malfunctioning muscles of a patient. This especially holds for the stiffness of the AFO. Generally, the AFO should be stiff enough to support the ankle's function, but also compliant enough to not restrict voluntary motion.

The optimal stiffness of an AFO for a patient can vary a lot, as the severity of the pathology differs and hence, the consequences, ranging from spastic to paralyzed muscles. It was found that issuing a sub-optimal AFO in the longer term may contribute to deterioration of physical function and gait. Thus, finding the optimal AFO joint stiffness for this group of patients and improving the speed of doing so, is an important clinical treatment goal.

Currently, this is achieved by a trial-and-error method consisting of fitting the patient with several orthoses. This method is time consuming and can possibly result in a sub-optimal AFO prescription. Ideally a human-in-the-loop setup is developed to find the AFO characteristics during tests using an AFO simulator. The corresponding AFO can then be fabricated and fitted to that specific patient. Hence, increasing the speed and quality of providing an AFO to a patient. However, current solutions are too expensive.

This assignment aims to create a proof of principle of a simplified, affordable, human-in-the-loop solution to vary the AFO stiffness, that enables clinicians to tune the AFO stiffness to a specific patient. This report describes the process of designing a lightweight AFO simulator with a continuously variable stiffness mechanism (VSM) and a predetermined torque-angle curve. The resulting design combines two key elements: A leaf spring of varying stiffness by changing the active length, and a cam part the serves as the transmission between the leaf spring and the AFO mockup. The design was fabricated and then validated with a dedicated AFO stiffness tester (BRUCE) based on manual deflection of the ankle-foot orthosis.

It was shown that the predicted plantarflexion stiffness range closely resembled the measured stiffness values. However, the measured dorsiflexion stiffness range was roughly two times smaller than predicted.

Concluding, the designed AFO simulator can change its stiffness, while being compact and lightweight. The potential of the design has been shown. Now it can be developed further into a fully functional AFO simulator system that can be worn by patients in a clinical gait laboratory setting.