Fakultät Technologie und Bionik
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Institute
Strategic Obsolescence Management: Developing a Process-Oriented and Financially Viable Concept
(2025)
Industrial machinery is designed for long operating periods, but many electronic and mechatronic components used in these systems are discontinued after a short product lifecycle.
This situation causes challenges for Strama-MPS, especially in the Global Service division, where long-term spare-parts availability and reliable customer support are required. When components are no longer available, urgent procurement, redesigns under time pressure, longer downtimes and higher service costs put additional load on internal departments and can negatively affect customer relationships.
This thesis develops a structured and financially viable approach to obsolescence management for Strama-MPS. The current situation was analysed using expert interviews and SAP and PRO.FILE data for the period 2018 to September 2025. The evaluation of more than 13,000 obsolete materials showed fragmented communication, insufficient lifecycle documentation and that only a few large suppliers systematically send PCN notifications, while many others do not. To summarise the results, a Power BI dashboard was created that shows portfolio age, part criticality, successor availability and supplier concentration. The analysis identified an average part age of 6.75 years, a cost-at-risk of around €1 million and a high-risk group mainly consisting of electrical and control components.
In a second step, the active parts portfolio was evaluated to identify future risks. Using manually cleansed Excel files and Power BI models, a lifecycle forecast was developed for the period 2026–2029. It highlights early-warning patterns in connectors, sensors, I/O modules and control units with short technology cycles and high dependency. These results enable earlier evaluation of alternatives, more controlled last-time-buy decisions and more proactive customer communication.
Based on these findings, the thesis proposes a target framework in line with DIN EN IEC 62402:2025-05. It defines responsibilities, decision and communication paths, and workflows between the relevant departments. A dedicated Obsolescence Manager is assigned as the central process owner and is supported by SmartPCN-compatible input formats, lifecycle dashboards and an implementation plan that starts with an internal pilot and later includes the roll-out of PCN Global as the OM software.
The strategic options were assessed using an MCDA, comparing reactive, proactive and strategic approaches. The results show that a dedicated role combined with suitable software offers a good balance between cost control, early-warning capability and acceptance. The financial analysis indicates that the concept can pay back within the first year by reducing emergency sourcing, redesign work and service delays, while also improving collaboration,
decision quality and long-term service performance. Overall, the proposed structure provides a clear basis for more consistent and reliable lifecycle handling across the organisation.
The primary aim of this research project was to determine the effects of shearing on the structure of a blend of biopolymers (PLA+PBAT) through tailored screw designs in a twin-screw extruder. To achieve this, 3 different twin intermeshing co-rotating screw designs of an extruder were used. The designs were mainly focused on the kneading and mixing part of the screw which has a shearing effect on the biopolymer. The experiments were carried out by keeping the temperature, screw speed and feed rate constant. To carry out the experiment, a 60:40 blend of PBAT and PLA was utilized.
The compounded pellets produced from the 3 screw designs were then used in a Blown Film machine. Furthermore, tensile test was conducted on the resulting samples. The shear strength and strain of the films were calculated. Tear test of the films were additionally carried out to validate the findings. Fourier Transform Infrared (FTIR) test was conducted to study the functional groups, identifying the chemical interactions and phase compatibility of the of PLA&PBAT blend.
The results showed that the screw with 3 kneading blocks (HS) and 2 kneading blocks (MS) exhibited almost similar ultimate strength and ultimate strain. The screw design with only conveying elements had lower ultimate strength and strain. The kneading blocks played a role on the mixing and shearing of the biopolymer structure in the blend.
This thesis represents the design and implementation of a virtual gearbox functionality as a system with an end goal to be used on the Electric Gokart platform.
The design includes a 3-part solution consisting of:
- Human-machine interface (HMI) – that is a physical hardware as a separate unit with its own housing
- Intermediary software for transfer of input information and output feedback of the user – as software code
- Control Model – MATLAB Simulink model to be run on the main computer of the platform to facilitate the motion control
Due to the system complexity and multidomain solution the work has been broken down and documented to focus on a specific aspect for each deliverable. The human machine interface focuses on the hardware aspect of the functionality – research on and evaluation of different components for the input, feedback and communication and the impact of each component to the further development of the intermediary software. The software part is focused on choosing and implementing an efficient and logical handling
of the sampling and relay of information to prevent the potential problem of
communication network overload. And finally, the Simulink Control Model will focus on investigating input information, processing and motion control realised via torque control. The information is to be used used in developing a system response model evaluating it on the prototype and allowing tuning via system identification in the MATLAB Simulink development environment.
Development of selection criteria and systematic methodology for the design of novel hydrogels
(2025)
Hydrogels are a broad field of materials with applications in many niche areas. To advance the state of the art, research should explore new combinations of chemical and practical components to discover syntheses with novel emergent properties. However, given the vast amount of information available, it is challenging to systematically narrow the search to an effective comparison of a few select candidates.
This work proposes a selection and evaluation methodology for building a comparative scope to decide on a set of hydrogel recipe components. Recipe design needs are determined using an existing bibliometric analysis of a hydrogel subfield, and available options are sourced from literature reviews, then assessed based on properties discussed in the literature. Candidates for the crosslinking initiation mechanism, the monomer system, and the crosslinking control method are evaluated separately and sequentially. Recipe permutations are possible as multiple choices are scored. The resultant recipe is a photoinitiated (LAP; irradiated at 380.5nm), thiol-ene (TMPMP-Maleimide), light-patterned (maskless PWM-DLP) hydrogel that swells and bends in response to water due to osmolyte (D-Sorbitol) diffusion. This novel formulation is not currently present in the literature; however, it does not exhibit any chemical or practical incompatibilities. A range of component concentrations, possible failure scenarios, and recommended fixes are provided for initial testing.
This thesis develops bio-inspired, multi-segment tendon-driven continuum manipulator through a structured, iterative design process. Combining piecewise constant-curvature modeling, for design validation, with hybrid soft-rigid joint fabrication, three prototypes explore trade-offs among anatomical scale, actuation efficiency, and structural compliance. Novel, internal, soft-rigid components, buckling-mitigation features and internally routed tendons are integrated and evaluated under a common experimental frame work. Demonstrations include single-finger grasps and coordinated bimanual object handling, confirming the manipulator’s viability for humanoid end-effector tasks. The final design produced a tip-load of ≈ 17N for a pinching grasp and ≈ 12N in a power grasp, with 4 degrees of freedom and a maximum bending angle of 209°. Future work will focus on closed-loop control, dynamic interaction testing, and scaling to multi-digit hands.
This thesis explores how origami-inspired modular structures—specifically uniformly thick, load-carrying designs—can be prototyped using accessible 3D printing work flows. We focus on translating geometric folding principles into real materials and hinges suitable for repeated deployment by designing printable panels and connectors, and by validating performance with a bar-and-hinge simulation approach.
Physical prototypes are fabricated and tested for packing ratio, deployment re
peatability, and stiffness-to-mass. Results indicate that thick-panel origami can
be produced with consumer 3D printers while retaining compact storage, rapid deployment, and promising structural behavior. The work outlines a practical path toward portable, reusable, and more sustainable engineering systems that minimize material use, support repair and reuse through modularity, and simplify logistics through high packing ratios.
This work presents a multidisciplinary evaluation of Carbon Fibre Reinforced Polyether Ether Ketone (CF-PEEK) as a core material for hybrid dental crowns, combined with lithium disilicate (E-max) veneers.
The objective was to assess the mechanical, manufacturing, and economic feasibility of introducing CF-PEEK into restorative dentistry through an engineering-driven approach.
A systematic literature review compared the elastic modulus, flexural strength, and density of CF-PEEK with conventional materials such as zirconia and porcelain-fused-to-metal.
Results show that CF-PEEK exhibits a modulus close to natural dentin and lower density, offering improved biomechanical compatibility and reduced stress transmission.
Additive manufacturing (3D printing) was identified as the most flexible and sustainable production method, minimising material waste and enabling customised crown fabrication.
The study concludes that the CF-PEEK + E-max hybrid crown is mechanically viable and aligns with sustainability goals, though improvements in bonding, colour masking, and clinical validation remain necessary.
This approach demonstrates how industrial engineering tools including TRIZ, QFD, and KANO can effectively guide innovation in dental materials and workflows.
This thesis presents the design and implementation of an automated control system for a laboratory-scale SETUR (Sedlacek's Blade-less Rolling Fluid Turbine) hydro turbine test rig. The goal was to enable precise and repeatable experiments by automating the regulation of the turbine’s water level and data acquisition process. The developed system integrates multiple sensors, including discrete liquid level sensors, pressure transducers, and a flow meter, interfaced with an Arduino-based controller.
A PID-based control algorithm with gain scheduling was designed to adapt to the nonlinear flow dynamics across different operating regimes of the turbine. The control loop operates at a 0.5 s sampling rate and employs layered signal filtering and calibration routines to compensate for sensor noise, offset, and scaling errors. The complete hardware setup includes signal conditioning circuits for analog sensors, digital communication for actuator control, and real-time data monitoring via serial output.
Experimental results demonstrate that the system achieves stable water-level regulation within approximately two minutes after pump activation and maintains steady-state operation without overshoot or sustained valve saturation. The overall measurement uncertainties were quantified as ±3.06 % FS for pressure and ±5.2 % FS for flow, meeting the predefined accuracy requirement of ≤ 5 % FS.
The developed automation platform provides a reliable foundation for further research on the SETUR turbine, including efficiency characterization, advanced control development, and future integration of IoT-based supervisory monitoring and data analysis tools.
This thesis explores how an already built Mini Mars Rover can autonomously navigate an uncharted maze, first by mapping it and then by applying different pathfinding strategies.
The Mini Mars Rover uses IR sensors for wall detection, encoder-based odometry for tracking movement, an IMU for heading corrections, for input for more accurate localization.
The strategy combines exploration techniques with practical path execution on real hardware, focusing on the challenges that come up when algorithms meet the physical world.
Exploration applied by using a combination of Breadth-First Search (BFS) with the Travelling Salesman Problem (TSP) approach, as well as a Partially Observable Markov Decision Process (POMDP) strategy. Although both methods showed promising results in simulation, in hardware testing same results were not gathered.
For the path planning, three pathfinding algorithms Flood Fill, Dijkstra’s, and A* are implemented and compared. The results of those algorithms and the strategy to adopt them into the robot is implemented.
The project demonstrates a possibility of adaptation of those algorithms and their feasibility.
The Mini MarsRover serves as a solid base for further development and improvements.
This thesis investigates the design and simulation-based evaluation of a yaw-rate control system using torque vectoring for an all-wheel-drive electric go-kart with independently driven wheels. The work is conducted within a purely model-based framework, employing MATLAB and Simulink to replicate the vehicle dynamics and control interactions in a controlled virtual environment.
Torque vectoring describes the distribution of drive torque between individual wheels to influence the yaw moment of the vehicle. This enables targeted improvements in stability, responsiveness, and cornering performance beyond what is achievable with steering input alone. In this study, yaw rate is selected as the primary control variable. A reference yaw rate is derived from the linear bicycle model, and the control objective is to minimize the error between the reference and the simulated actual yaw rate by applying corrective yaw moments through differential torque allocation.
A Proportional-Integral-Derivative (PID) controller is implemented to track the reference yaw rate. Gain tuning is performed using MATLAB’s PID Tuner, leveraging the system transfer function extracted from the simulation model. The complete control system is integrated into a modular Simulink model of the go-kart, which incorporates the 2-DOF bicycle model for lateral and yaw dynamics, as well as subsystems for maneuver generation and torque vectoring logic.
Controller performance is assessed through standard vehicle dynamics test maneuvers, including ramp steer, step steer, and double lane change. For each maneuver, simulations are performed both with and without torque vectoring, allowing quantitative comparison of yaw rate tracking accuracy, stability, and trajectory.
The results demonstrate that torque vectoring substantially improves yaw rate tracking and reduces the understeer tendency of the simulated vehicle, particularly during transient maneuvers. Even in a simplified small-scale vehicle model, the benefits of active yaw moment control are evident, underscoring the relevance of torque vectoring for enhancing dynamic performance in electric vehicles with independent wheel actuation. The modular simulation framework developed in this work also provides a foundation for future experimental validation on the physical research platform as well as further developments on the simulation model.