TU Delft Repository

This thesis explores the use of reset control to improve disturbance rejection in systems subjected to wideband noise. In the high-tech industry, there is a continuous push for improved performance, particularly in achieving fast and stable motion with nanometer-level precision. Linear controllers, though industry-standard, are constrained by limitations such as Bode's gain-phase relation. Reset control offers a promising alternative, but its behaviour under wideband disturbances remains unexplored. However, such excitation is common in the context of active vibration isolation. The wide-spectrum excitation may result in dominant slow or excessive resetting, depending on the system. In both cases, the behaviour of the reset element will be different than designed. Also, the traditional method of Describing Function (DF) will not sufficiently represent the reset element's behaviour under such conditions, as it is defined for single sinusoidal excitation. This thesis studies the Power Spectral Density (PSD) of the reset triggering signal of the reset element to understand the resetting behaviour. The method of Best Linear Approximation (BLA) is applied to enable the analysis of the reset element in frequency domain. Furthermore, a novel method is developed to shape the reset triggering signal, to achieve the desired behaviour of the reset element at the frequency of interest. Both simulations and experiments showed the feasibility of the method in achieving the desired behaviour of the reset element. Depending on the properties of the system, this will result in improvement of the disturbance rejection.

Amsterdam's extensive network of bridges and quay walls is facing a critical maintenance backlog due to structural underfunded infrastructure maintenance. The many upcoming bridge maintenance projects to ensure safety are expected to cause significant more hindrance to road users. However, complex road networks with high traffic density in urban areas like Amsterdam make it difficult to foresee how the effects of different maintenance projects interact and how the projects can be planned efficiently to reduce hindrance.
This study aims to optimise the planning of a given set of bridge maintenance projects to reduce hindrance to road users, combining a genetic algorithm with traffic simulations using a new estimation method to improve the assessment of simultaneous closures. The genetic algorithm selects the optimal starting time and execution duration for each bridge while minimising maintenance cost and additional travel times for the modalities car, freight and bicycle. Using the fast static traffic simulation of the Urban Strategy Tool of TNO, a new estimation method for evaluating simultaneous closures is proposed, accounting for interdependencies between bridges. Results of a case study on four urban bridges in Amsterdam show that the new method provides more accurate estimates of additional travel time compared to previous methods and generates better solutions. Moreover, the fast proposed optimisation framework makes it possible to evaluate multiple scenarios in reasonable time to assist in decision making of maintenance planning.

Scalp electroencephalography (EEG) is a widely used, noninvasive tool to assess brain activity. EEG is valuable for various neurological conditions like epilepsy and migraine. Conventional EEG uses gel-based electrodes, ensuring good signal quality but requiring complex setup and the removal of patients from their natural environments. Portable EEG devices with water electrodes offer easier home measurements but pose signal quality concerns. This thesis aims to evaluate the signal quality of water electrodes compared to gel electrodes and investigate the feasibility of home-based EEG measurements.
Three experimental protocols were used: resting-state (RS), single visual evoked potentials (SVEP) and 12 Hz steady-state visual evoked potentials (SSVEP). These signals were measured 1) in the lab, once with a gel cap and once with a water cap; and 2) at home with a water cap. Signal quality was assessed with the artefact proportion, the signal-to-noise ratio (SNR), the relative 12 Hz SSVEP power, the relative alpha band eyes-closed RS power, the presence of the Berger effect, and the SVEP waveforms.
In the lab setting, the water and gel cap showed similar signal quality as illustrated by a similar SNR, relative alpha power, alpha band presence and SVEP waveform. However, an increase in artefacts and slight decrease in relative 12 Hz power and SVEP amplitude show remaining shortcomings of the water cap compared to the gel cap. When comparing the water cap between lab and home settings, the performance closely matches. This is demonstrated by the similar SNR, relative 12 Hz power, alpha presence and SVEP waveform and amplitude. Differences were a decrease in artefacts and an increase in relative alpha band power for the signal measured at home.
Provided that the limitations of the water cap can be mitigated by further developments, the otherwise relatively comparable signal quality between the gel and water caps suggests that water-based EEG systems could be a viable alternative to traditional gel-based systems. Furthermore, the positive home study results suggest that home-based EEG measurements could be a viable alternative to lab-based studies with the help of a water electrode EEG cap.

The project “Other Traditions” explores diverse knowledge systems, emphasizing oral traditions and ecological knowledge exchanges. Set in Stockholm, Sweden, the project focuses on the Stockholm City Library, a significant architectural landmark, and its surrounding areas, including Observatory Hill. The initiative addresses three key issues: optimizing library spaces for informal meetings, creating inclusive spaces for minority groups, particularly refugees, and enhancing biodiversity.
The project proposes connecting the library with a nearby annex using small workrooms, creating an urban forest as a living laboratory, and incorporating culturally resonant spaces like the Qa’a for storytelling and language learning. The urban forest expansion aligns with Stockholm’s environmental goals, enhancing air quality and providing leisure space. The design integrates with the local landscape, ensuring accessibility and monumentality, while also respecting the historical significance of the site.

This graduation project explores the problem of teaching engineering education through the course Understanding Product Engineering (UPE) to first year bachelor students at the TU Delft faculty of Industrial Design Engineering, which is a significant issue in the context of the reduction of time allocated to technical subjects in the programme. Moreover, students are not applying their engineering knowledge and skills in their design projects, possibly meaning the way it is educated is not effective. The primary goal of this research is to design an experiential machine, aiming to address the lack of practical, hands-on learning experiences in early engineering education through the development of a prototype and accompanying educational module. This is guided by the Productive Failure learning approach.

The project began with an initial exploration phase, where the different subjects of UPE were explored, a questionnaire was conducted and literature was reviewed to understand the end users’ needs and how to effectively teach subjects. From this, several key findings emerged, including the choice of direction for statics with a focus on beam bending. Additionally, it was discovered that teaching relies heavily on the way motivation in students is created.

Based on these insights, the next phase involved generating design concepts and developing a proof of concept for an experiential machine, guided by the requirements that followed from a deeper look into the subject of statics and beam bending. This concept phase culminated in the embodiment of the Educational Deflection Analyser (EDA), which was further refined through technical assessments and user tests.

To validate the design, two user tests were conducted, and the results indicated that the EDA is a functional proof-of-concept with the potential to engage students by sparking their curiosity to learn something new. Despite requiring some future iterations concerning the usability and full integration in the educational context, the project successfully developed a setup to teach first year students the fundamentals of product engineering.

In conclusion, this report demonstrates that with continued development, the EDA holds the potential to become an effective learning tool in the future to make engineering education enjoyable and see the application reflected in design projects. Future work could focus on the improvement of the user-friendliness, elaborate evaluation and digital integration of the electronics.