This design project marks the collaborative efforts of Translas, a prominent welding company based in the Netherlands, and Skelex, a scale-up enterprise specializing in exoskeleton design. Translas developed the 8XE fume extractor torch. However, a common complaint of the new torch is its decreased usability and potential ergonomic risk. To address this problem, Skelex and Translas have united their expertise to develop an exoskeleton-lite solution, aimed at assisting welders in carrying the torch. The aim is to alleviate the physical strain of welding and enhance overall ergonomics. A literature review of welding, ergonomics, and exoskeletons reveal that musculoskeletal disorders form a significant societal problem with large financial losses, which provide opportunities for cutting-edge companies as Translas and Skelex, and form the groundwork for a problem definition, design goal, and drivers. Through a numerical model the specific ergonomic concerns of the 8XE torch are analysed, which is also used to assess the final design. It was found that generally static welding forces with the 8XE are within safe parameters as recommended by ergonomic experts. The bending stiffness of the 8XE cable contributes significantly to the wrist moment, being estimated to reach values of 0.5Nm in conventional welding, compared to the 0.7Nm contribution due to weight. Friction in the ball-and-socket joint, and inertia ore comparatively low, and do not significantly cause ergonomic concerns. An iterative prototyping phase diverges to explore various ways to offload the 8XE’s weight on the wrist to stronger body parts, converging to two good concepts. A simple strap off loading the weight on the wrist to the lower arm for a limited amount of welding positions, and an exoskeleton worn on the waist and shoulders carrying the full weight of the torch using a tool balancer. After three user tests, two of which with welders in industry, both concepts were combined which led to the creation of AeroGrip. AeroGrip is an exoskeleton-lite product that eases welding by changing the weight distribution on the upper extremities, improving ergonomics and helping welders ‘be their ultimate’; they can weld safely for longer, with more precision, whilst experiencing less strain. It is a system that attaches to the welding cable through a ladder strap and buckle. A hook attached to a Kevlar cable can be pulled out and attached to the special AeroGrip Gloves, which feature a leather tab with grommet. The Kevlar cable is attached to a power spring via a spool in the casing, which ultimately results in a Tension of ~12N. Two final user tests, and comparative numerical analysis show that AeroGrip eases welding, provides an ergonomic benefit, and is convenient to use. FEM analysis and friction analysis ensure feasibility, whilst an assembly plan and business case ensure viability.

Objective: To develop a steerable neuroendoscopic instrument (SNI) based on user requirements found by several means of user research, and to evaluate this instrument on usability and safety. Only 5% of the potential intraventricular neuroendoscopy (INE) cases are currently treated with endoscopy. For the other 95%, an endoscopic approach is impossible, due to the risk of damaging the surrounding tissue by movement of the endoscopic system, needed to reach the affected areas inside the ventricles. A hand-held SNI is theorised to overcome these problems. Methods: A human-centered design (HCD) approach was taken to come to engineering solutions. Expert interviews, surveys and secondary research were performed to acquire the design input. Intermediary prototypes were developed and tested. For the final experiment, 10 participants, of which one neurosurgeon, performed a task in a box trainer. The endoscope was equipped with markers, used to evaluate the movement of the endoscope during the test by means of video analysis, comparing a rigid instrument and the new prototype in a two-tailed paired T-test. Usability was measured through a questionnaire. The spans between digit 1-2, 2-5 and 1-5 of the dominant hand of the participants was measured. Results: A biopsy forceps with a shaft length of 290mm, with a laser-cut articulating portion of 14mm and maximum bending of 40° was developed. Handle dimensions were based on a grip between the distal phalanges and the thenar area of the palm of 10th percentile hand measurements to enforce a stable grip. Significantly less non-angular movement than in the old instrument(p=0.009) was observed. Angular movement reduction was significant in one direction (p=0.032) but not in both (p=0.063). The handle prototype is slightly too large. The forces on the controls were comfortable. No relationship was detected between the finger span measurements and the usability score per participant. Conclusion: The prototype consists of a handle design based on human factor guidelines and multiple user evaluations, and an articulate tip based on DEAM’s technology, now with dimensions optimised for INE biopsy and ETV. Safety is improved by significantly limiting movement in the system during use.

The human body, although seemingly symmetrical, can in fact be highly asymmetrical. Our bodies are predetermined by our DNA and co-shaped by our environment. This leads to most of the world's population having a discrepancy in leg length either from birth or developed during their life time. It is completely natural and goes unnoticed, as changes are incremental and people get used to it. On the contrary, when undergoing total hip replacement surgery and waking up with one leg longer than the other, the change is almost instantaneous and immediately noticeable. Current surgical solutions do not address this issue in a practical manner within the operating theatre, leading to surgical teams developing their own methods and procedures to evaluate the change in patient's leg length.   Introducing new workflows to medical professionals often entails neglecting the protocols they spent years practicing. This thesis identified this bottleneck and instead of introducing new methods and procedures, it was decided to build on existing ones. This was done by exploring common surgical workflows in respect to total hip replacement and determining an approach to enhance surgical team's capabilities in evaluating leg length discrepancy.. Important in achieving this goal it to make any given design solution effortless, reliable and undisruptive to various workflows In order to do so, user research was performed by joining multiple surgical teams within the OR, thereby observing and evaluating their methods. One method in particular stood out, which is best described as the 'loaded assessment'. During this assessment the surgeon or circulating nurse will centre the patient's feet, apply pressure to the heels and try to evaluate the discrepancy. Although this method being seemingly simple, its execution is difficult to perform by a single person and varying pressure differences may confuse the assessment. Following the initial research phase, co-creation sessions with technical experts were organised, after which various concepts were developed and tested on the basis of feasibility, desirability and viability. Finally, a functional prototype based on the loaded assessment principle was developed and tested for its functionality and conceptual expectation.