Background: Currently colonoscopies are difficult procedures to complete without complications. Due to the limitations in the state of the art flexible colonoscopes specialized maneuvers are required in order to allow the colonoscope to travel into the colon and reduce colon stretching. This thesis proposes a novel self-propelling mechanism designed to enhance the current flexible colonoscopes allowing for a better completion rate and fewer complications in colonoscopies. Methods: First an analysis was made of the fundamental types of propulsion and how well they could be used for locomotion inside the human colon. In order to determine the conditions the design has to meet a list of requirements was made. A wide variety of concepts were considered, which were then reduced to the three most promising concepts. These concepts were further developed and out of these, the most promising design was chosen. This design was adjusted in order to create a proof-of-principle prototype which was used to validate the design and give new insights into the type of self-propulsion used. Results: The prototype is able to perform locomotion in all tested tube/instrument diameter combinations, including tubes with a significant larger diameter than the instrument. Furthermore, the prototype is also able to perform well in tubes with an irregular shape and with a conical shape, both with and without lubrication. The effect of added weight to the tubes was also investigated and showed no significant effect. The efficiency of the prototype, as determined by the slip ratio, showed no significant variation during these tests. Discussion and Conclusion: The proof-of-principle experiments demonstrated that the design is capable of performing locomotion in the tested scenarios with better than expected efficiency. The lack of significant variation of slip ratio in tubes with a larger diameter than the prototype itself were unexpected and could significantly change the design of future iterations of the instrument. The issues which came up during the experiment gave new insights into the working of this type of locomotion which were used to make recommendations for future iterations of the design and recommendations for further tests, which could be performed to investigate unexplained results. The current design meets all the requirements set out for it and gave valuable new insights which will be useful for future iterations of the design making it a good first step towards developing a better colonoscope.

In the history of medicine and surgery, a slow transition is made from open surgery to minimally invasive surgery. Nowadays, natural orifice transluminal endoscopic surgery (NOTES) is investigated and tested. A NOTES procedure includes flexible instruments, which are inserted through natural orifices such as the mouth, nose, anus or vagina. The instrument then passes transluminally towards the areas of interest. Benefits of this surgery method compared to conventional open surgery include, among others: the reduction in tissue trauma, no external scar tissue, less blood loss and a shorter recovery period. However, the method requires highly advanced medical devices that are slender and able to bend and form different paths to reach the area of interest. Bio-inspired by the movement and the propulsion of a snake, new instruments are being developed that provide a follow-the-leader motion (FTL-motion). In a follow-the-leader mechanism, the user steers the tip of the instrument. The position given to the tip is stored and passed on proximally from segment to segment. This thesis aims to improve the existing mechanically controlled FTL-mechanisms, in which the shaft is controlled with four-cable control. In this research, a cylindrical mechanical path-planning module is designed and manufactured: the Cryptex Programmable Memory Mechanism (CPMM). The cylindrical shape improves cable-control, as it can simultaneously steer one cable and its antagonist, and control the motion of a compliant shaft in one plane. Two prototypes were developed: a machined prototype and a 3D printed prototype. Both designs were manually tested in four phases: individual components and subassemblies; the key component solely; integrated design excluding the key component; completely integrated design. It is concluded that the design of the 3D printed prototype is limited by the accuracy of the parts and the material properties. The machined prototype shows promising results, as it can form diagonal and curved paths as an output. Even though the performance of the CPMM prototype leaves room for improvement, it validates that the proposed concept can provide the follow-the-leader motion.

The human brain integrates tactile sensory information from the fingertips to efficiently manipulate objects. Sensory impairments due to neurological disorders, e.g. stroke, largely reduce hand dexterity and the ability to perform daily living activities. Several feedback augmentation techniques have been investigated for rehabilitative purposes with promising outcomes. However, they often require the use of unpractical, expensive, or complex devices. In this work we propose the delivery of vibrotactile feedback based on the Discrete Event-driven Sensory feedback Control (DESC)to promote motor learning in post stroke rehabilitation. For this purpose, we prototyped a novel wearable device, namely the DESC glove. It consisted of a soft glove instrumented with PolyVinylidene Fluoride (PVDF) sensors at the fingertips and eccentric-mass vibration actuators to be worn on the forearm. We proceeded with the characterization of the device, which resulted in promising outcomes.
The DESC glove was tested with ten healthy participants subsequently in a pick and lift timed task. The effects of augmented vibrotactile feedback were assessed comparing it to a baseline, consisting of wearing the device unpowered. The results of this pilot study showed a decrease in the time necessary to perform the task, a reduction in the time delay from load force to grip force activation and a diminishing of the grip force applied on the object, which led to a lower breakage rate in the intervention condition. These promising outcomes encourage further experiments with stroke survivors to validate the effectiveness of the device to improve hand dexterity and promote stroke rehabilitation.

Background: During minimally invasive procedures, tissue damage can be limited by using smaller incisions and by using naturally occurring body orifices to reach the intervention site. During these procedures the need can arise to transport tissue. Think of a biopsy or the removal of polyps. This calls for a tool that can transport tissue and is also flexible such that the tool can be introduced via natural occurring body orifices. Currently either suction based techniques or forceps are used for these procedures. However, both show suboptimal behaviour. Friction-based transport, which is based on the egg laying principle of parasitoid wasps, is not prone to these sub-optimal behaviour modes but is not yet used in flexible systems. Methods: A mechanical analysis was conducted to generate an overview of the challenges that arise in flexible friction-based transport. This resulted in a list of requirements based on which possible concept solutions were analysed. Themost promising design for a flexible friction-based transport mechanism has a flexible shaft that consists of a number of wire ropes in combination with ring magnets. This shaft was manufactured and validated by transporting gelatin tissue phantoms with different material properties with the shaft in straight and in a curved position. After validation of the flexible shaft, an ergonomic handle was designed resulting in the final prototype. This final prototype was also tested by transporting gelatin tissue phantoms. Results: From the results can be concluded that the flexible shaft is able to transport tissue phantoms with different material properties while in straight and curved (R=59mm) position. The final prototype is showed that continuous transport was possible from the tip of the flexible shaft to the end of the handle with the shaft in straight and in curved position. The position of the shaft (straight vs. curved) did not result in a significant difference in the transport rate. Discussion and Conclusion: It can be concluded that friction-based transport is possible in a flexible tool. The mean transport rate in straight position ( 2.3 § 0.29 mm/cycle) is comparable to the transport rate of a rigid friction-based transport mechanism with comparable dimensions. This new flexible friction-based transport mechanism shows great potential to be beneficial for a number of medical procedures.