In this paper, we focus on how the qualitative vocabulary of Dynalearn, which is used for describing dynamic systems, corresponds to the mathematical equations used in quantitative modeling. Then, we demonstrate the translation of a qualitative model into a quantitative model, using the example of an object falling with air resistance.
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An important issue in the field of motion control of wheeled mobile robots is that the design of most controllers is based only on the robot’s kinematics. However, when high-speed movements and/or heavy load transportation are required, it becomes essential to consider the robot dynamics as well. The control signals generated by most dynamic controllers reported in the literature are torques or voltages for the robot motors, while commercial robots usually accept velocity commands. In this context, we present a velocity-based dynamic model for differential drive mobile robots that also includes the dynamics of the robot actuators. Such model has linear and angular velocities as inputs and has been included in Peter Corke’s Robotics Toolbox for MATLAB, therefore it can be easily integrated into simulation systems that have been built for the unicycle kinematics. We demonstrate that the proposed dynamic model has useful mathematical properties. We also present an application of such model on the design of an adaptive dynamic controller and the stability analysis of the complete system, while applying the proposed model properties. Finally, we show some simulation and experimental results and discuss the advantages and limitations of the proposed model.
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De zogenoemde “21th century skills” worden, aldus het Ministerie van Onderwijs, steeds belangrijker. Het zijn eigenschappen die we terugvinden in de eindtermen van vrijwel alle hbo-opleidingen en die – in de woorden van Donald Schön – de kern zijn van een “reflective practitioner” : een vakvrouw of –man, die zichzelf in complexe situaties kan sturen en daardoor productief blijft. Eerder onderzoek van het lectoraat Pedagogiek van de Beroepsvorming heeft aangetoond dat een leeromgeving gericht op zelfsturing aan drie condities moet voldoen: er moet sprake zijn van praktijkgestuurd onderwijs, studenten moeten de kans krijgen een dialoog aan te gaan over de zin en betekenis van hun ervaringen in het praktijkgestuurde onderwijs en studenten moeten medezeggenschap hebben over hun eigen leerproces. Met name het realiseren van een dialoog blijkt echter heel moeilijk te zijn. Zowel docenten als studenten (en ook de onderwijsmanagers) zijn gewend aan onderwijs waarin zin en betekenis nauwelijks ter discussie staat. Het gevolg is dat ze vooral gericht zijn op reproductief en niet op betekenis-gericht leren. Zelfsturing vereist evenwel deze laatste vorm van leren. Zelfsturing vereist een dialoog over de zin en betekenis van ervaringen die de student “raken”. Dergelijke ervaringen roepen veelal emoties op die in eerste instantie niet begrepen worden. Zin en betekenis zijn “geen dingen in een doosje”; ze worden gaandeweg duidelijk in een gesprek waarin de docent verklaart noch verheldert, maar samen met de student op zoek gaat naar de juiste woorden. Dat zijn woorden waarvan de student voelt dat ze haar in staat stellen iets uit te drukken dat voorheen nog niet onder woorden gebracht kon worden. In dit boek wordt vanuit verschillende perspectieven en op basis van empirisch onderzoek ingegaan op de vraag in hoeverre het hbo er in slaagt een dergelijke dialoog met haar studenten te realiseren. Tevens wordt stilgestaan bij methoden om zo’n dialoog te realiseren.
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The COVID19 pandemic highlighted the vulnerability in supply chain networks in the healthcare sector and the tremendous waste problem of disposable healthcare products, such as isolation gowns. Single-use disposable isolation gowns cause great ecological impact. Reusable gowns can potentially reduce climate impacts and improve the resilience of healthcare systems by ensuring a steady supply in times of high demand. However, scaling reusable, circular isolation gowns in healthcare organizations is not straightforward. It is impeded by economic barriers – such as servicing costs for each use – and logistic and hygiene barriers, as processes for transport, storage and safety need to be (re)designed. Healthcare professionals (e.g. purchasing managers) lack complete information about social, economic and ecological costs, the true cost of products, to make informed circular purchasing decisions. Additionally, the residual value of materials recovered from circular products is overlooked and should be factored into purchasing decisions. To facilitate the transition to circular procurement in healthcare, purchasing managers need more fine-grained, dynamic information on true costs. Our RAAK Publiek proposal (MODLI) addresses a problem that purchasing managers face – making purchasing decisions that factor in social, economic and ecological costs and future benefits from recovered materials. Building on an existing consortium that developed a reusable and recyclable isolation gown, we design and develop an open-source decision-support tool to inform circular procurement in healthcare organizations and simulate various purchasing options of non-circular and circular products, including products from circular cascades. Circular procurement is considered a key driver in the transition to a circular economy as it contributes to closing energy and material loops and minimizes negative impacts and waste throughout entire product lifecycles. MODLI aims to support circular procurement policies in healthcare organizations by providing dynamic information for circular procurement decision making.
The Ph.D. candidate will investigate the seismic response of connection details frequently used in traditional Dutch construction practice, specifically in the Groningen area. The research will focus on the experimental and numerical definition of the complete load-deflection behaviour of each considered connection; specifically, the tests will aim at identifying stiffness, strength, ductility, and dissipative behaviour of the connections. The experiments will be conducted on scaled or full-scale components that properly resemble the as-built and retrofitted as well connection details. The tests will involve monotonic and cyclic loading protocols to be able to define the load and displacement response of the connection to reversal loads, such as earthquakes, as well as the development of failure mechanisms under such loading cases. Possibly, also dynamic tests will be performed. Numerical models will be created and calibrated versus the experimental findings. Characteristic hysteretic behaviours of the examined connection types will be provided for the use of engineers and researchers.
