Chalmers Open Digital Repository
Not a member yet
26247 research outputs found
Sort by
Arduino/ROS2 Control Software Development for an Elbow Exoskeleton - The development of the exoskeleton software contributes to the modularity and scalability of the system
No full textThe following work presents the development of control software for an elbow exoskeleton, utilizing Arduino and ROS2. The exoskeleton is modeled as a 1-degree-offreedom system with the primary goal of providing support for the user and assisting with movements. Additionally, the system is designed to be modular and scalable, allowing for future adaptations.
To achieve these objectives, research questions were created to more precisely understand what needed to be done to achieve the goals. The questions were also based on the limitations of the projects that were set to make the project feasible since it could easily become very complex. The limitations included using a preexisting frame of the orthosis to focus on software development rather than mechanical design,
focusing on development for one arm with a range of motion of 0-90 degrees, and using a basic user interface based on touch sensors.
The development process began with a preliminary study to identify suitable components and pre-existing orthosis. The hardware configuration and system architectures were then established to prepare the hardware for the software implementation and to facilitate easy identification and debugging. The software was developed separately for ROS2 and Arduino. The Arduino software was developed to interface with hardware components ( touch sensors, encoder, and motor) while enabling serial communication with ROS2. ROS2 was structured into two primary nodes, one for the trajectory and the other for serial communication. Finally, the system underwent testing, beginning with partial tests to verify individual components, followed by full system testing to ensure functionality and seamless interaction.
The results are validated through experimental testing, demonstrating that the exoskeleton provides assisted movement when the sensors are pressed. The system is adjustable to user preference, with movement data visualized in a graph. Additionally, ROS2 allows the user to change to the preferred range of motion. The modular architecture allows for the creation of additional ROS2 nodes for specific tasks.
Challenges encountered during the development, such as actuator torque limitations, are discussed, along with potential future improvements. These include changing to a more powerful actuator to provide better assistance or to fully compensate for the loss of upper arm muscle functions.
In summary, this report presents the development of a modular and scalable elbow exoskeleton using ROS2 and Arduino to facilitate assisted movements, offering opportunities to enhance performance and expand its functionalitie
TAILORING LUXURY RETAIL STRATEGIES Exploring Consumer Needs in the Swedish Market
No full textAs consumer heterogeneity grows, firms in the Swedish luxury industry face increasing
challenges in responding to the distinct preferences of emerging generational cohorts,
particularly Generation Z, while retaining the loyalty of traditional consumers such as
Generation X. Due to the conservative nature of the luxury sector, characterized by
institutional inertia and resistance to change, response to shifts in the industry is often
slow and cautious. Existing research on generational differences in luxury consumption
has largely focused on international markets, leaving the Swedish context underexplored.
This study investigates how Generation X and Generation Z consumers in Sweden
perceive luxury, what motivates their luxury purchases, and how they navigate the luxury
customer journey. Drawing on 24 exploratory and 10 in-depth semi-structured
interviews, the findings reveal that Generation X views luxury through a product-centric
lens, emphasizing quality, durability, and heritage. In contrast, Generation Z consumers
perceive luxury more aesthetically and symbolically, often associating it with peer
validation, indulgence, and as a sustainable alternative to fast fashion. The study identifies
clear differences in generational customer journey behaviors, with Generation Z favoring
digital engagement and seamless transitions across channels, while Generation X values
physical experiences and longer-term relationships. A distinctly Swedish perspective
also emerged, such as understatement and Scandinavian aesthetic. Based on these
insights, the study proposes three strategic focus areas for luxury firms: Locally tailored
assortment, Personalizing for loyalty, and Seamless customer journeys. Together, these
provide a roadmap for shifting from traditional luxury strategies to a more customer-
centric approach that aligns with generationally diverse expectations of luxury
Multi camera extrinsic calibration
No full textAutonomous driving has the potential of increasing traffic safety and enabling greater automation in our society. These systems rely on high precision sensor data, not the least from cameras, in order to detect and map out the environment around a vehicle. In doing this, knowledge about how the sensors are mounted is of crucial importance. This is typically calibrated in a static rig upon manufacturing a vehicle, but after driving for a while the orientation of sensors might change due to bumps and vibrations, thus requiring regular recalibration.
This thesis presents an automated refinement method for the rotations of cameras mounted on a car. There are four fisheye cameras with a wide field of view, that together can be used to form a 360◦ view of the surrounding ground. This is what you typically see on the display when parking a modern car. There are also three regular cameras, of which one is looking forwards and two are looking backwards but slightly to the left and right, respectively. Given images taken by the cameras at the same time, we find pixel coordinates that correspond to the same real world point for cameras with pairwise overlapping fields of view. Using this information we then optimize all camera poses simultaneously, starting from an initial pose estimate.
The performance is evaluated by two criteria. Firstly, we consider the surround view images that are created by stitching together fisheye camera images projected onto the ground plane. Looking at the overlap between cameras, the alignment of e.g. lane markings and shadows in the ground plane indicates the quality of a calibration. Secondly, we manually annotate point correspondences for each overlapping camera pair in each scenario. These are used to calculate a quantitative error metric, essentially telling us how close the pixel coordinates are to actually originate from the same real world point for the given camera poses.
The results indicate that our method achieves an accuracy comparable to that of a static calibration rig. This is a very promising result, since the time and space consuming rig calibration could possibly be switched for a calibration method that can run while the car is driving. Additionally, the fisheye camera calibration appears to achieve an accuracy comparable to other state of the art methods, while also being
applicable to a wide range of driving environments and allowing for other cameras to be included in the calibration as well
Circularity in Product Development - a case at SKF
No full textAs we are facing environmental challenges globally, the traditional take-make-disposal
liner model is no longer sustainable and society as a whole must evolve. Organizations
and industries currently operate under such traditional liner model should
particularly be at the forefront of the transformation. Circular economy, driven
by product life extension, reuse, remanufacture, recycle, etc., is recognized as a
sustainable economic system and has been an area of research to develop frameworks,
methods and tools to support organizations in making the shift. SKF, a
Swedish company which has a high vision of sustainability, has initiated a Circularity
Program and determined to implement circular product development within the
organization. Therefore, a master thesis project was kicked off to explore collaborative
approaches to implement circularity in product development. A backcasting
approach was taken in the project to establish goals, identify the gaps between the
future and the present, and define key initiatives for the organization to make future
planning. The project aims to develop a methodology, building upon existing
theories and concepts related to sustainable and circular product development, to
implement circularity in product development at the case company. Meanwhile, the
project outcome could give inspirations to other manufacturing organizations on
circularity implementation, as well as to academia on future researches in the area
of circular product developmen
Characterization and Hydrotreatment of Model Compounds and Industrial Feedstocks for Renewable Diesel Production
No full textEnhancing Information Circularity in Generic Discrete Event Simulation Development - Creating a Simulation Model that Utilizes a Developed User-Friendly Interface for Evaluating Production Lines
No full textIn global manufacturing organizations, effectively sharing operational knowledge across geographically dispersed sites remains a significant challenge. This master’s
thesis, conducted in collaboration with SKF’s Manufacturing Development department, addresses this issue by developing a generic discrete event simulation (DES)
model integrated with a user-friendly interface. This thesis aims to support knowledge sharing and benchmarking across SKF’s production lines while simplifying
simulation adoption, especially for users without prior expertise in simulation. The developed solution integrates Siemens Tecnomatix Plant Simulation with Microsoft’s
Power Platform tools such as Power Apps, Power Automate, and SharePoint to enable structured data input and automated model generation through a user-friendly
interface by emphasizing customizability and reusability. This allows users to configure machine setups, process parameters, and layout alternatives without the need
for advanced programming background. Focusing on the context of bearing manufacturing, the solution illustrates how standardization and simplified user interaction
can enhance information circularity within a global industrial enterprise. The research methodology combines a literature review with qualitative interviews and quantitative analysis
of SKF’s production systems to identify critical simulation parameters, user interface requirements, and overarching organizational goals. The resulting concept supports efficient, accessible,
and simulation-driven decision-making and internal benchmarking. It enables manufacturing sites to visualize and assess production scenarios with minimal manual effort.
This work contributes to both academic research and industrial practice by enhancing the usability of DES and promoting scalable knowledge transfer through the application of digital technologies
Radarbaserad närvarodetektion i grupprum
No full textEffektiv användning av gemensamma utrymmen, såsom grupprum på universitet,
är viktigt för både resursoptimering och förbättrad tillgänglighet. Traditionella bokningssystem
saknar stöd för att visa faktisk närvaro, vilket ofta leder till att resurser
förblir outnyttjade. Detta projekt undersöker användandet av en frequencymodulated
continuous wave-radar för att detektera närvaro i grupprum.
Den använda radarmodulen, Texas Instruments AWR1843BOOST, arbetar i 76-
81 GHz-bandet. En initial analys av radarns utdata visade att både position och
hastighet hos detekterade objekt kunde extraheras. Ett program utvecklades för
att klassificera ett rum som ledigt eller upptaget baserat på information om de
detekterade punkterna. Ett rum betraktades som ledigt om inga punkter uppvisade
hastighet under en definierad tidsperiod. Däremot, om två punkter med hastighet var
belägna inom både ett visst avstånd och tidsintervall från varandra, klassificerades
rummet som upptaget.
Slutgiltiga tester visade att systemet korrekt klassificerade tomma och upptagna
rum under både korta och långa testperioder. Vid test av tio specialfall misslyckades
endast ett fall, vid två av tre försök. Resultaten visar att radarbaserad närvarodetektion
i grupprum är möjlig, och att detta system framöver skulle kunna integreras
i en lösning som täcker hela campusområden
Design and synthesis of TQ-based conjugated polymers with hybrid glycolated side chains for improved packing and performances in organic photovoltaics
No full textHeavy-duty truck simulator: a tool to plan charging and charger layouts
No full textDigital Twins (DTs) and simulation tools are virtual representations of physical objects or processes that can collect information from the real environment to represent, validate, and replicate the physical twin’s present and future behaviour [1]. The aim of this thesis has been to gather the data requirements needed to prepare virtual tools capable of assessing mining sites, where traditional diesel-powered trucks are replaced by electric vehicles, with the organisation, analysis and incorporation of mining haul electric trucks in mines. This shift is driven by the need to reduce carbon emissions and improve sustainability in the mining sector. For the correct functioning of these virtual tools data requirements have to be recruited to make these tools work correctly. An iterative research method has been chosen for this, reviewing the improvements in each step until the desired result is achieved. The research method used begins with a comprehensive literature review to know which is the status of the electrification in mines in the actuality and the existence of related virtual tools. The following step was to determine which were the research questions and elaborate the corresponding experiments modifying the backbone code, iterating all the needed times. This thesis has explored the limitations in the existence of literature when referring to the simulation of mining heavy duty trucks in open pit mines, mostly due to the absence of real available data. Nevertheless, it has been demonstrated the potential of DTs and simulation models in optimizing the operation of electric mining fleets. The developed simulator provides a valuable tool for planning charging strategies, managing fleet sizes, and responding to dynamic environmental conditions. The study contributes to the goal of achieving efficient mining operations through the adoption of advanced digital technologies
Friction Models and Friction Compensation for Real-Time Actuator Control
No full textAbstract
Friction is a non-linear disturbance present in all electromechanical systems, which produces an opposing force or torque that resists motion. The effects become apparent and particularly problematic at low velocities, where the nonlinear friction characteristic reveals itself through phenomena such as limit cycles and stick-slip motion. This complex behavior presents significant challenges in high precision motion control systems. This thesis investigates methods for friction compensation in electromechanical actuators. Compensation strategies are implemented on an Engine Control Unit (ECU) which controls an Electronic Throttle Control (ETC) unit in real-time. Experimental results demonstrate that friction compensation techniques
can significantly enhance the tracking performance and accuracy of the ETC at low velocities. Furthermore, the thesis highlights the trade-off between control signal activity and tracking performance, showing that different methods of compensation exhibit different characteristics in how they balance these objectives