Fleet Cleaner B.V. is a Dutch company which deploys a wheeled hull-fixed Remotely Operated Vehicle (ROV) to clean biofouling off the Vertical Sides (VSs) and the Flat Bottom (FB) of the hull of seagoing cargo vessels, while berthed at the harbour. To ensure maximal cleaning coverage, accurate localization to keep track of the robot trajectory on the ship hull is essential, but also challenging. Contrary to the VS case, drift-free localization from motion sensors is not applicable on the FB. Instead, the current system relies heavily on operator input, who in turn relies on features (such as the quay wall, a line feature) appearing on imagery from a Forward Looking Sonar (FLS) to determine the robot pose. Human inattentiveness caused by the high workload of cleaning operations makes this method error-prone and sensitive to drift. In the future, Fleet Cleaner aims to develop an autonomous robot to relieve the operators from the task of localization and improve cleaning performance. As no previous work was performed on this matter, this thesis is a contribution to this vision, by developing a sonar-based framework enabling drift-free localization of a ship hull cleaning robot on FBs. Before the conceptual phase, two objectives are formulated to achieve the thesis goal. The first is to provide a sonar-based algorithm measuring the line parameters of the quay wall, as lateral and heading reference. The second objective seeks to fuse the FLS-based measurements with motion sensors to achieve drift-free localization. From there, the operating conditions relevant to the systems are defined, and both functional and performance requirements are formulated, where the latter define metrics that measure the accuracy of the systems w.r.t. manually defined ground truths. For the first objective, three candidate solutions for tracking the quay wall line parameters are selected. These are first implemented with recorded data in an iterative tuning procedure, then validated where the Total Least-Squares (TLS)-based line tracker with Gaussian filtering arises as a proof of concept. Although the algorithm is fast enough to function for each incoming sonar image, it does not fulfill the requirements for accuracy and robustness, a problem solvable by tuning with better data and the use of filters. For the second objective, also three sensor fusion algorithms are selected. Analysis of their properties with regards to performance revealed the Extended Kalman Filter (EKF) as the most suitable solution, where tuning was performed heuristically. Validation tests again showed partial success, with fast computation times and greatly improved but still insufficient accuracy of the FLS measurements, although localization drift was reduced within the required limits. Mainly, the poor predictions from auxiliary sensors degrade performance, but also the imperfect nature of manually defined ground truths exaggerate the errors. To improve and complete the localization system, it is recommended to implement trajectory optimization for an improved fit of estimated poses with sensory data, and Simultaneous Localization And Mapping (SLAM) based on weld line detection to reduce longitudinal drift.

Over the past decades Minimally Invasive Surgery (MIS) has become a standard in abdominal surgery. Due to limited dexterity and bad ergonomics the field of MIS is shifting towards Robot-Assisted MIS (RAMIS). Simultaneously, the field is using increasingly small and steerable instruments to reduce invasiveness. Surgeon now work with fragile instruments and tissues and are not able to feel the forces they apply. This can lead to unwanted damage to patient and instrument. In an effort to reduce the risk of accidental damage, this work presents a force sensing strategy that is able to measure tip forces in RAMIS using 3mm shaft actuated tip articulated instruments. The system uses a sensorized trocar fixed to the same frame as the instrument to eliminate interfering forces occurring at the trocar. Bending in the instrument due to the applied force at the tip is measured using Hall effect sensors with a silicone transducer. Prototype testing and validation show the proposed sensing system is both accurate and reusable.

At this moment there are more than 150 different designs of CMMA in existence. To aid the designer to develop a new or improved CMMA or choose what the design to use, a classification system is developed during the literature research. It is based on the geometrical advantage (GA) of the CMMA, and on the input and output port motion paths. Their properties resulted in 5 different classes, with a total of 50+ CMMA designs. The mechanical efficientcy (ME) of CMMA or compliant mechanisms in general can be non- optimal because of the elastic energy storage during motion. A technique called static balancing, can be applied to improve the efficiency of the device. A new way to apply the static balancing, without manual preloading, is developed for a straight-line micro mechanism. This technique allows applying static balancing on batch scale that was not available before. A MEMS design is developed and a prototype fabricated and tested. Another step closer in creating statically balanced for compliant mechanical micro motion amplifiers.

The use of optical fibres as distributed vision sensor within a contactless handling system is discussed in this study. The three primary light colours and a volume diffuser will be used to detect the edge of an object levitating on an air-bearing table. One building block of a bigger system is used that consists of one receiving fibre in the centre surrounded by three transmitting fibres, with each transmitting one primary light colour. Various experiments were executed to find a range where the object edge can be detected. The transition range for horizontal and vertical movement is found. The backscattering of light within the volume diffuser turned out to be much larger than thought. This backscattering causes a small light intensity range. Also, some disruptions in the emitted light caused no logical transition ranges. A model is made to see what happens to the transition ranges when the disruptions are eliminated. The red transmitting fibre is investigated to see the individual contribution to the light intensity received in the receiving fibre. The transition range got from that measurement is translated into the transition range for the green and blue transmitting fibres. Through interpolating the ranges, a total measurement range is found where the object edge can be detected at whatever angle the object is positioned. A bigger system can be made by connecting more building blocks. The proposal for future research is to investigate the positive or negative effects of connecting multiple building blocks.

The offshore industry is adopting Autonomous Underwater Vehicles (AUVs), to decrease the costs associated with surveying underwater sites. Despite requiring less human supervision, AUVs still depend on costly servicing from a vessel, before and after deployment. Combining an AUV with an Unmanned Surface Vessel (USV), a survey vessel that operates without humans on board, could drastically reduce operational costs. This thesis focuses on the crucial requirement of this combination: the autonomous docking of the AUV to the USV. Current studies focused on the AUV-USV combination lack effective solutions for docking in rough ocean conditions, while this is key for its operational employability. These studies have explored horizontal docking approaches, while an unexplored alternative is a vertical docking approach from below the USV. This approach may experience reduced influence of waves, as the wave disturbance acting on the AUV and the USV are phase synchronized. The objective of this study is to evaluate the viability of vertically docking an AUV to a USV in rough seas, using the Lobster Scout AUV as a case study for an initial performance evaluation. This study first identified and scoped the key elements for this initial performance evaluation, which included the waves, the USV, the Lobster Scout, the Docking Station (DS), and vertical docking Guidance Navigation and Control (GNC). Furthermore, the scope was limited to the critical docking stage, where the vehicles are within meters of each other. The study used simulation as the primary method to investigate the thesis objective and a 2-Dimensional (2D) model was developed to simulate the system dynamics, which was fitted and verified using a variety of methods, including analytical calculations, mesh convergence studies, experiments, and visual analysis. To determine the viability of the vertical docking approach of the USV-AUV combination, a probability distribution-based method was developed. Viability was expressed in terms of the maximum operational sea state and the estimated operational up-time. Since docking success under the presence of waves is described probabilistically, the requirement was set that at least 991 out of a 1000 docks should be successful. Furthermore, Monte Carlo simulations were used to obtain the docking performance over a variety of sea states, navigational settings, and different guidance and control methods. A target state vertical guidance method using way-points was designed with various Proportional-Integral-Derivative (PID) based controllers to guide the Lobster Scout to the DS. It was also determined whether kinematic prediction or polynomial prediction could improve docking performance and the impact of navigation on docking performance was investigated. It was found that the vertical docking approach shows promise for enabling a reliable AUV-USV combination for the Lobster Scout in medium to rough seas, with a significant wave height of 1.65 m and 3.6 m respectively, resulting in an estimated annual operational up-time of 59 % to 94 % in the North Sea. Furthermore, there is potential to achieve even higher sea states with improved GNC methods. Overall, this study suggests that the vertical docking approach can lead to a viable AUV-USV combination with improved operational employability compared to current docking studies using horizontal approaches, although the author is of the opinion that both approaches require further investigation.

The Atalanta is a palm-sized, insect-inspired, flapping-wing micro air vehicle developed by the University of Technology Delft. In its current form, the Atalanta has a lift-to-mass ratio of 0.12 which inhibits it from taking off. Getting the Atalanta to fly would greatly benefit the research into areas such as aerodynamic modelling, on-board electronics, control and navigation and more. Designing and realizing a new, energy-efficient wing-system capable of producing 1.5 gram lift is found to be the most effective solution, with an expected lift-to-mass ratio of 0.85. Developing this new wing-system requires the design, manufacturing and integration of two parts: a wing and a compliant hinge. The wing is a wing-shaped, rigid plate that pushes air around to generate lift. The hinge is the interface between the Atalanta body and the wing, and allows the wing to passively rotate, i.e.: pitch, around its spanwise axis. For the fabrication of the wing, a hybrid structure is created by stacking sheets of different materials on top of each other, each with its own purpose. The sheets are laser cut before assembly to distributed material only where needed. The result is a wing consisting of a carbon frame for stiffness, a Mylar sheet for enclosing the wing surface area and a double-sided adhesive layer to bond the two together. For the compliant pitching hinge, a cross axis configuration of three leaf-flexures is selected. The combined pure bending motion of all three flexures allows the wing to rotate around its pitching axis. The flexures are fabricated and subsequently integrated into the wing structure, forming the new wing-system. The two main tests qualitatively asses the performance of the new wing-system. The first test measures the average stiffness of four hinges, and finds it to be a factor 27.8 higher than was expected. Measurement errors, incorrect input parameters, hinge flexure misalignment and corrugation at the edges of the flexures all can reduce the factor to 13.9, but the dominant reason is estimated to be curving of the flexures along their width. The second test determines the kinematic profile of the new wing-system; i.e. the sweeping and pitching angles during a single stroke. The results show that the wing-system operates at its resonance frequency of 8.5 Hz. This indicates that the energy efficiency of the new wing-system should be improved compared to the current wing-system. The 8.5 Hz sweeping frequency does mean a lower lift generation than expected, but this can be improved by reducing the mass of the wing and optimizing its topology. With some weight saving improvements the new wing-system should be more energy efficient while producing more lift compared to the current wing-system. The design and manufacturing processes are more flexible and consistent which makes experimental optimization of the mechanical properties of the wing-system easier. The novel cross axis hinge concept proves to be a valuable addition to the wing, although its fabrication can be improved upon.

Drones are becoming an ever increasing part of our lives. From airshows to surveillance systems, their use varies greatly and, as technology improves, this variety will continue to increase. As drones get smaller, new applications arise. For example, drones for monitoring crops or searching for survivors in hard to reach places in disaster areas. One of the main fields of improvement to drone design is energy efficiency. The more energy efficient a drone is, the longer it can fly and the more it can carry. This is the objective of the Atalanta project. It seeks to develop a drone with a wingspan smaller than 15 cm and an improved energy efficiency over other drones. It does this by two means. Firstly, it uses a bio-inspired flapping wing solution, mimicking the methods used by insects to fly. This carries a greater efficiency over the more ubiquitous rotary wing design. Secondly, it looks to apply resonance, allowing more energy conservation between wing flaps. In its current state, the Atalanta project has gathered an expansive amount of theoretical knowledge, but lacks the validation a prototype would provide. This report gathered the knowledge contained within the Atalanta project and supplemented it with new information generated in the last two years. It identified three main challenges to overcome and provided a set of guidelines to overcome them. The challenges are as follows: Firstly, the total design is too heavy for the theoretical lift generated by the wings. Secondly, the wings, in their current form, are too heavy for an actuator to operate at the right frequency. Thirdly, little documentation exists on the design of the resonant element the design has to be built around. If all three of these challenges are addressed, it should be possible to create a flying prototype for the Atalanta project using an external power source and external control. To overcome the limits of the generated lift, varying actuators were evaluated. As no actuator was found meeting the projects requirements, a gearbox solution was sought instead. Through the use of a linear frequency divider, the available power from an actuator could be doubled by doubling the operating frequency of the actuator without changing the flapping frequency of a wing. A linear frequency divider was developed for this purpose. As this element also fulfils the role of the Atalanta body, the third challenge was also addressed through this element by designing it to function as a resonant element, vibrating at the desired frequency. This linear frequency divider was successfully developed, but was unable to be integrated into the prototype within the available time. To address the weight of the wings, a vacuum forming method was investigated. By applying heat to a film of plastic and pulling it over a mold using a vacuum, a wing of a desired shape can be created. By introducing localised folds in this wing, it can be reinforced and be made stiffer. Although this seemed promising, no suitably light wing was produced using this method, but further research is likely to produce positive results. As only mylar was investigated in this paper, evaluation of other materials could prove productive. Alternatively, using a combination of vacuum forming and local reinforcements may well create a near rigid wing. Despite the increase in losses due to the heavier than desired wings, the drone presented in this paper could theoretically fly for short periods of time, as the losses of the flight are compensated for by the energy provided by the used actuator. It was originally predicted that the Atalanta would have a power density requirement of 30 W/kg. Despite the heavier wings and the increase in weight from the components added by the linear frequency divider, the new loss to mass ratio is only 38.4 W/kg. The weight of the prototype has increased as well, however. Despite all this, the actuator is predicted to be able to deliver 1.15 watts of power with the losses being 0.713 watts. As such, with the addition of the linear frequency divider, the prototype can theoretically fly, if integrated properly. Also of note is the lack of optimisation for the linear frequency divider. As this is the first paper investigating this part, a substantial amount of time was spent evaluating the effectiveness of the part. As such, further investigation in this area could lead to further optimisation or even the inclusion of a second divider, allowing the frequency of the actuator, therefore its power, to be doubled again.

Atrial fibrillation is a cardiac arrhythmia resulting from abnormal electrical conduction and impulse formation within the atria. To address this condition, a minimally invasive procedure called cardiac ablation is performed. Real-time visual feedback during this procedure plays a critical role in determining its success. Photoacoustic imaging is a technique capable of providing real-time visual feedback. Integrating photoacoustic capabilities into existing Radiofrequency ablation catheters poses a significant challenge, which this thesis addresses. The proposed integrated solution employs optical fibers for light delivery and an ultrasound transducer for signal reception. This work investigates the design of two light delivery systems for integrated photoacoustic-guided surgery. Monte Carlo simulations are employed to study three-dimensional light propagation in tissue, informing the catheter design specifications. Optimal fiber distances and orientations within the catheter are determined based on normalized fluence values and illumination spot size—critical parameters for assessing the amount of delivered light, its area of coverage, and depth of penetration. The methodology presented applies to various photoacoustic applications. The simulation study was able to successfully inform design specifications and it was able to establish a relation between design variables and the evaluation criteria such that it can be referred to for future designs. The comparative study yielded a better-performing design configuration and its optimal specifications were found out. This proves the use of a simulation-based evaluation to design a photoacoustic intracardiac catheter. In the final phase of this research, an experiment is set up to validate the light delivery of the design, which provides a clear outlook for the future of these designs into fabricated products.

A future version of the DEMCON Needle Placement System (NPS) for use in the Magnetic Resonance Imaging (MRI) scanner requires accurate and small actuators that are MR (Magnetic Resonance) safe; actuators that can safely operate without interfering with the MR environment. The pneumatic stepper motor was chosen for actuation of the aiming segments of the future NPS. The pneumatic stepper motor can be made out of MR safe materials and its actuation principle is MR safe. MR safe, small size pneumatic stepper motors that produce high resolution motion however, do not exist. The goal of this thesis is to design and prototype such a pneumatic stepper motor and test its performance. An MR safe, high resolution pneumatic stepper motor was designed. This motor, called the PneuScape, was designed to fit in the orientation module of the NPS. The design of the PneuScape is based on an escapement mechanism. A torque is applied to move the output and the escapement anchor indexes this movement, creating a step. The PneuScape currently has the smallest designed step size st = 0.83º of any MR safe pneumatic stepper motor. A prototype of the Pneuscape was developed using rapid prototyping techniques and its performance was evaluated. The total prototype did not meet all design requirements, in particular the requirement of maximum positioning error. Torque application does not work reliably and results in the motor skipping steps, diminishing the motor's accuracy. The escapement mechanism however, shows promising results in its performance. Recommendations were given to improve the prototype. If the prototype is improved with aid of the recommendations, a future version of the PneuScape is expected to meet the design requirements. Finally, the work in this thesis has made science take a step towards high resolution MR safe actuation.

The ever-growing demand for high-performance materials and more functional 3D printing has raised tremendous interest in advancing Multi-Material Additive Manufacturing (MMAM). Developing C-FRTP 3D printing through FDM Technology opens new scalable FRP solutions. These components possess exceptional properties such as specific strength, recyclability, impact/chemical resistance, and geometrical complexity. Researchers have successfully exploited FDM technology to print C-FRTP composites but lack high interface bonding between the reinforcing fibers and thermoplastic polymer matrix. Moreover, C-FRTP is limited to weak frictional forces and mechanical interlocking. Besides, porosities are observed at the interface, which results in overall mechanical weakness. Various Meso-level C-FRTP 3D printing methods and print heads have been developed and standardized, but more knowledge is needed of essential 'In-Nozzle' C-FRTP impregnation dynamics. During In-Nozzle impregnation, solid-dry fiber and molten Thermoplastic polymer matrix bond inside the print head before extrusion. This master thesis explores the challenges and potential solutions by conceptualizing a functional ’In-Nozzle’ impregnation extruder capable of extruding proper C-FRTP composites using FDM printing. Initially, a theoretical framework is presented on melt impregnation dynamics and Interface adhesion, followed by experiments as validation. Based on the melt impregnation analysis observations, a limited permeability of Thermoplastic polymer melt is observed. These are primarily from the high viscosity of the thermoplastic materials (PLA) and the dense fibers. Applying an overflow of melt with extensive external pressure achieves a smoother and faster melt flow around the interface. Tensile strength experiments underscored the dependency on the exposure time and encapsulation of fibers by matrix and showed an increase in IFSS compared to the neat thermoplastic polymer. Further research is recommended to augment contact surfaces between fibers and the matrix. This research highlights the current challenges and lays the foundation for future advancements in C-FRTP 3D printing through in-nozzle impregnation, offering insights into improving material compatibility, impregnation quality, and interfacial bonding.

With the ever-increasing demand for a more efficient production process, the thickness of silicon wafers for the solar cell industry has shown a decreasing trend over the years. This makes the substrates more and more fragile, with an increasing breakage rate as a result. Research at the TU Delft has been done on contactless handling, using air bearings and actuators. A suitable and integrated sensor system in the air bearings would complete the package of actuator and sensor. The sensor should be able to detect and track objects floating above an air bearing transport system. Previous work on this subject investigated the possibilities of using optical fibers as a vision distributor for a camera sensor. This proved to be a promising concept, but the optical fibers showed to have a limited reach. This research focusses on increasing the detection range of an individual optical fiber. A commercial light diffuser plate is used to increase the vision of an optical fiber. The effect of the light diffuser is experimentally tested with a test setup that can simulate the motion of a moving rectangular object that resembles a solar cell. Different transmission trends observed by the optical fiber are received for various angles of motion of the moving object. The detection range of an individual optical fiber is increased up to an 8mm radius around the optical fiber, dependant on the angle of motion of the object. The distributed sensor concept is verified by tracing the observed signals from the optical fiber back to object position and angle of motion.

The Atomic Force Microscope (afm) is a small scale measuring device, with a lot of benefits over other existing measuring techniques. Unfortunately, measurement speed is not one of them. Many have tried and succeeded to improve the measurement speed, but there is still room for improvement. By passively lowering the Q-factor, a measurement can be sped up, while still be compatible with other speed improvement techniques. To passively lower the Q-factor, we propose measuring in a medium more dense then air. First in a liquid, de-mineralized water, to prove the effect, and later in a gas, co2, to keep the samples clean. Our models predict a speed increase of 0.3559 ms per measured point, or 6.941 min per image of 5 μm × 5 μm with 512 lines in liquid. The experiments show an increase of 0.4180 ms per point, or 8.155 min per measurement. In the much less dense gas a 0.031 01 ms per point or 0.6550 min per frame is calculated. The experiments show an increase of 0.027 29 ms per point with a total of 0.5300 min per frame. Both in liquid and in gas an improvement is observed. When measuring in a liquid, the speed increase of 8.155 min per frame is noticeable when a small area on a single sample is measured. Measurements in gas, with an increase of 0.5300min per frame only become interesting when multiple frames need to be measured, since a gas measurement does take longer to set up. Changing the used measurement gas to a more dense gas could make single frame measurements more interesting.

Large multi-object spectroscopy telescopes measure the light from millions of stars and galaxies for the use in astronomical studies. One part of these telescopes is the fiber positioner, where a few thousand of optical fibers need to be individually positioned very accurately. The problem with current fiber positioners is the small patrol area, the long production times and the light loss due to the incorrect movement of the tip. The goal of this research is to design a new type of positioner which solves the mentioned problems; large patrol area, fast production and reduction of light loss. The final design is an r-theta design with one rotating motor and a displacement mechanism to move the fiber horizontally over the focal plane. The design is based on the best suitable straight line mechanism from the Reuleaux collection: the Scott-Russell linkage. Flexures are used in the final design. This eliminates backlash and slip-stick effects in therefore improves the accuracy. An experiment with a scale model has been done to show that an exact horizontal positioning with the fiber exactly orthogonal is possible with this design. By adjusting two parameters in the design, the movement and the angle between the horizontal and the fiber can be adjusted. This means an exact movement can be finetuned in order to reduce light loss. The flexure based displacement system is monolithic and can be made by laser cutting. This reduces the production and assembly time of the system drastically. The design meets the patrol area requirement and shows large potential to increase this area up to an estimated 4 times the pitch. In order to validate the remaining requirements of this very promising design, additional experiments with a real scale fully functional prototype is needed.

The goal of this study is to develop a measurement setup that can accommodate the water-cooled modules present in the innovative e-beam lithography tool developed by Mapper Lithography and to perform flow verfication measurements on them. The overall objective is to verify the stage-stability requirements set for the Matrix-machine with regards to FIV by observing the induced cooling forces. This requires measuring in 6-DOF, over a wide frequency range (10-300 Hz) and at a very low noise level (e-11 N^2/Hz). Most challenging for this design is to be able to observe the FIV while in the presence of a variety of dominant environmental disturbances. The final design consists of a mass-optimized triple mass-spring-damper (MSD) system, weighting 828 kg. It uses six low-noise piezoelectric force transducers to observe the 6-DOF reaction-forces exerted by the modules. These modules under testing are supported by the piezos through custom designed stiff-flexible struts with a high axial/radial stiffness ratio. This improves measured signal and protects the piezos from damaging bending moments. This sensitive part of the measurement setup is isolated from floor vibrations by a double MSD Vibration Isolation (VI) platform (granite stones on airmounts). Acoustic shielding has been achieved by a custom designed enclosure that disconnects at the bottom granite stone. Flow vibrations in the supply tubing are discharged at various stages. Water flow is provided under constant pressure and flow rate by a hydrostatic pressure vessel. This prevents measuring distinct resonances from asynchronous motor characteristics inherent to a centrifugal pump. Verification measurements have been performed showing a noise floor characteristic at the level of the theoretically predicted effect of all disturbances combined (2.5 e-11 N^2/Hz). The main findings of this study are: - when aiming to measure very low-level dynamic reaction forces (0.35 microN-rms) in the presence of dominant disturbances that transmit through parasitic stiffnesses, quartz piezoelectric sensors proof to be a better solution when compared to (seismic) accelerometers. - flow vibrations induced in supply tubing can have a significant impact on the measured signal, if the stiffness train that connects the sensor with the measurement setup is relatively low. An effective method to minimize this disturbance is to discharge the bulk of the input to different stages of the vibration isolation platform, if present. - of all disturbances, environmental acoustics have shown to be most difficult to shield. The most effective means to reduce its effect is to fully enclose the sensitive part of the measurement setup and to rigidly connect this casing to a heavy mass with an attractive transfer path to the sensor e.g. the bottom stage of a two MSD VI platform. - when measuring direct forces using sensitive piezoelectric sensors that cannot withstand transverse loading / bending moments, stiff-flexible support struts with a high axial/radial stiffness ratio (roughly > 500) are found to be a solution. Concluding, the design process detailed in this thesis describes a method on how to effectively design a low-level reaction force measurement system, while in the presence of a variety of disturbances. In the report, generic design guidelines are listed that can serve as a reference to others when aiming to measure low-level FIV.

Both quadcopter Micro Aerial Vehicles (MAVs) and Flapping Wing MAVs (FWMAVs) are constrained in Size, Weight and Processing power (SWaP) in order to achieve flight tasks that include attitude and velocity stabilisation, as well as obstacle avoidance. Conventional sensory and control approaches, such as those relying on inertial, visual and Global Positioning System (GPS) sensors, can fulfil these tasks using sensor fusion. However such approaches do not score well in terms of SWaP criteria. Very simple proportional feedback control laws using single optical flow vectors from very basic high frame-rate low-resolution cameras provide a promising path to achieve aforementioned tasks. This thesis shows that in theory these control laws are well suited for stabilising a FWMAV, and could be used for a high-drag adapted quadcopter MAV within bounds. Simulations confirm these findings and illustrate robustness to noise and additional emergent behaviour such as sideways wall avoidance and trajectory following, however simulations also show that disparity between walls can lead to unintended rotational behaviour during vertical translation. The system is tested in experiment on a quadcopter-like setup with onboard processing, using only ADNS 9800 computer mouse optical flow sensors for flight control. Results show that the system behaves similarly to simulation, however the sensory configuration used is highly dependent on texture in environment and light conditions. For future work it is recommended to investigate optical flow sensors in more detail to obtain reliable output on a vibrating platform (such as a FWMAV) in a broader range of texture and light conditions. Preliminary results from theory, simulation and experiment indicate that the addition of derivative feedback could strongly enhance performance on a quadcopter MAV and remove the requirement for high drag.

The work presented in this report is an attempt to allow density-based topology optimization algorithms to take into account machining costs when optimizing. To this end, and estimation model for the cost of 2.5-axis CNC milling was developed based on the principles of Design for Manufacturing. This estimation model was implemented in a generic topology optimization algorithm in five steps of complexity. The behaviour of the model was evaluated at each step by means of a set of experiments, showing how the addition of the cost estimation influences the optimization results. The most promising results from the experiments are validated with Autodesk Fusion 360, with which the designs were programmed to be machined on a CNC mill. The machining times from this software were used to calculate the actual machining costs and these were compared to the machining costs estimated by the optimizer. Two formulations of the method were found to be useful for estimating the machining cost of designs. A simple formulation that uses the shape factor and the differentiation between internal and external pockets to estimate the cost resulted in a cost saving of 13% at the expensive of a compliance increase of 9%. The more complex formulation uses multiple pocket domains to evaluate pocket-specific properties. This allowed a more accurate estimation of the costs, but did not result in a better performing optimization. The cost saving was comparable at 12%, but the compliance increased by 16%. It was concluded that there is a use for both methods. The simple formulation allows to find cheaper designs, but does not allow much control in the cost estimation. The complex formulation however can be used to fine-tune the method for a specific situation, which could enable it to perform better that the simple formulation.

Multi­-material 3D inkjet printing has great potential for rapid prototyping and manufacturing of functional mesoscale structures when novel inks are combined into a fully integrated AM-process. This process can be faster and cheaper than conventional methods to produce functional structures. Research is conducted on a large range of potentially inkjet­-printable materials to extend current possibilities with 3D inkjet printing. Material incompatibility together with strict fluid properties limit the range of multifunctional inks available for an integrated print process. This raises challenges such as printing with three or more materials, and finding inkjet printable materials that can be cured simultaneously using the same curing method. The aim of this research is to print functional structures using at least three materials consisting of a structural, support, and conductive material, requiring only one curing technique involving UV light exposure. An experimental setup of PiXDRO LP50 inkjet printers and various printhead assemblies are used to conduct experiments. Suitable off the shelf available inks are selected after a state of the art literature review. Stratasys Vero­series and Stratasys SUP706B are industry standard, compatible materials and cure using UV induced photopolymerisation. They are chosen as structural and support material, respectively. Novacentrix Metalon JS­B25P and Mitsubishi NBSIJ­MU01 silver nanoparticle inks are chosen as conductive inks. First, multi­material printing is set up and extended to 3D printing using the structural and support material inks only. Afterwards, conductive inks are tested for resistivity and behaviour on different substrates before integrating with the structural and support material ink into a multi­material 3D print. Conductive nanoparticle inks show good conductivity on photopaper substrate, but not when printed on top of structural material. Several experiments are performed to document ink behaviour and optimise performance. A workflow is designed allowing the conversion of complex CAD models to inkjet ­printable files. Custom support material density for stronger supports can be generated using an in-­house developed conversion application. Proof­ of ­concept multi­-material functional structures are printed showcasing success of the proposed methodology.

The Lunar Zebro is a small moon rover that needs an advanced chassis to endure the harsh environment that the moon brings. To arrive at a solution for such a frame or chassis creativity and hard work are necessary. Whereas hard work is a given, creativity is not and it may need a helping hand. Design synthesis methods, of which brainstorming is a basic example, aid engineers and designers with reaching better solutions. Currently, however, which method works best for a given scenario is unknown. The purpose of this research is to determine which synthesis method works best for concept generation, with the focus lying on generating innovative solutions for frame design. A meta-method is created to evaluate the performance of different synthesis methods when applied to design cases. This meta-method consists of executing fifty case-method combinations, built up from pairing ten design synthesis methods with five design cases, which are focused on frame design primarily. The combinations are then evaluated using a self-made rubric. In the end, it became apparent that different methods apply well at different stages of the design process and at different system levels. Some work well to orient, understand the supersystem and therefore have an positive yet indirect influence on the final outcome. Some work well to generate concepts, bring new ideas at system level. Others apply well after a concept is already generated, only being useful to improve subsystems.