14 research outputs found

    Optimized state feedback regulation of 3DOF helicopter system via extremum seeking

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    In this paper, an optimized state feedback regulation of a 3 degree of freedom (DOF) helicopter is designed via extremum seeking (ES) technique. Multi-parameter ES is applied to optimize the tracking performance via tuning State Vector Feedback with Integration of the Control Error (SVFBICE). Discrete multivariable version of ES is developed to minimize a cost function that measures the performance of the controller. The cost function is a function of the error between the actual and desired axis positions. The controller parameters are updated online as the optimization takes place. This method significantly decreases the time in obtaining optimal controller parameters. Simulations were conducted for the online optimization under both fixed and varying operating conditions. The results demonstrate the usefulness of using ES for preserving the maximum attainable performance

    Adaptive multivariable intermittent control: theory, development, and applications to real-time systems

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    Intermittent Control, as a control scheme that switches between open and closed-loop configurations, has been suggested as an alternative model to describe human control and to explain the intermittency observed during sustained control tasks. Additionally, IC might be beneficial in the following scenarios: 1 - in the field of robotics, where open-loop evolution could be used for computationally intensive tasks such as constrained optimisation routines, 2 - in an adaptation context, helping to detect system and environmental variations. Based on these ideas, this thesis explored the application of real-time multivariable intermittent controllers in humanoid robotics as well as adaptive versions of IC implemented on inverted pendulum structures

    Proceedings of the ECCOMAS Thematic Conference on Multibody Dynamics 2015

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    This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: ● Formulations and Numerical Methods ● Efficient Methods and Real-Time Applications ● Flexible Multibody Dynamics ● Contact Dynamics and Constraints ● Multiphysics and Coupled Problems ● Control and Optimization ● Software Development and Computer Technology ● Aerospace and Maritime Applications ● Biomechanics ● Railroad Vehicle Dynamics ● Road Vehicle Dynamics ● Robotics ● Benchmark ProblemsPostprint (published version

    Ein mobiler Serviceroboter zur Automatisierung der Probenahme und des Probenmanagements in einem biotechnologischen Pilotlabor

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    Scherer T. A mobile service robot for automisation of sample taking and sample management in a biotechnological pilot laboratory. Bielefeld (Germany): Bielefeld University; 2004.In biotechnologischen Laboratorien ist die Qualität der typischerweise pharmazeutischen Produkte ein wortwörtlich lebenswichtiges Ziel. Die Qualität der Zellkultivierungen wurde historisch nur durch off-line Messungen von physikalischen Prozessparametern wie pH und pO2 sichergestellt. Biologische Parameter wie die Zelldichte und -viabilität wurden nur off-line gemessen, weil das dazu notwendige Probenmanagement hochkomplizierte Manipulationen und Analysen beinhaltet und deshalb nicht automatisiert werden konnte. Es gibt zwar mehrere automatisierte Geräte, um einem Labortechniker zu assistieren, aber kein System, welches das gesamte Probenmanagement automatisiert. In dieser Arbeit wird ein neuer Typ von Serviceroboter präsentiert, der aus einem auf einer mobilen Plattform montierten Roboterarm besteht und diese Lücke schließt. Dieser Roboter muss eine ganze Reihe von Problemen bewältigen: Er muss seine Position im Labor bestimmen können (Lokalisation), er muss eine kollisionsfreie Bahn zu den beteiligten Geräten finden können (Bahnplanung mit Hindernisvermeidung), er darf bei seinen Bewegungen keine Menschen gefährden oder Laborausrüstung beschädigen (Kollisionsvermeidung), er muss die zu bedienenden Geräte erkennen und ihre Position präzise messen können (Bildverarbeitung), er muss sie bedienen können (Armsteuerung), er muss Objekte greifen können (Greifer und Finger) und er muss sie gefügig handhaben können, um sie nicht zu beschädigen (Kraftregelung). Er muss autonom sein, um nur die allernotwendigste Menge an Benutzereingriffen zu benötigen, und doch durch ein Laborsteuerprogramm kontrollierbar sein, um Eingriffe zu erlauben. Schließlich muss er einfach durch ungeschultes Personal zu warten sein. All diese Aspekte werden von dem in dieser Arbeit präsentierten neuen Robotersystem abgedeckt.In biotechnolgical laboratories, the quality of the typically pharmaceutical product is a literally life-important goal. Historically, the quality of the cell cultivations was ensured by on-line measurements of physical process parameters like pH and pO2 only. Biological parameters like cell density and viability were only measured off-line, because the necessary sample management involves highly complicated manipulations and analyses and could therefore not be automated. Various automated devices to assist a laboratory technician do exist, but so far no system to automate the entire sample management. In this work a novel type of service robot consisting of a robot arm mounted on a mobile platform is presented that closes this gap. This robot has to master a multitude of problems: It must be able to locate its position in the laboratory (localisation), it must be able to find a collision-free path to the involved devices (path planning with obstacle avoidance), it must not endanger humans or damage laboratory equipment while moving (collision avoidance), it must be able to recognize the devices to be manipulated and measure their precise position (computer vision), it must be able to manipulate them (arm control), it must be able to grasp objects (gripper and fingers) and it must be able to handle them with compliance in order to not damage them (force control). It must be autonomous in order to only require the least possible amount of user intervention, and yet controllable by a laboratory control program in order to allow intervention. Finally, it must be easily maintainable by non-expert personell. All these aspects are covered by the novel robot system presented in this thesis
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