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Dissertations / Theses on the topic 'Shaping machine'
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Dubovský, Dávid. "Analýza rizik nástrojářské dílny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232113.
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This master`s thesis deals with a hazard analysis of selected machinery according to an actual legislative documents in Slovakia, which were taken over from Europien Union directives. The thesis is focused on exploring legislation related to the safety of toolroom workshop in the Czech Republic and Germany. Because of that was done the recherché of harmonized standards in these countries. Subsequently is made the identification of hazards under recherched standards and assessment of control system based on the performance level of the system. In the end are all obtained data evaluated and the precautionary measures are suggested. With taking care of economic factors are finally proposed the possibilities of the elimination of risks.
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Stewart, Gregory Edward. "Two dimensional loop shaping controller design for paper machine cross-directional processes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0015/NQ56628.pdf.
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Valtazanos, Aris. "Decision shaping and strategy learning in multi-robot interactions." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8091.
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Recent developments in robot technology have contributed to the advancement of autonomous behaviours in human-robot systems; for example, in following instructions received from an interacting human partner. Nevertheless, increasingly many systems are moving towards more seamless forms of interaction, where factors such as implicit trust and persuasion between humans and robots are brought to the fore. In this context, the problem of attaining, through suitable computational models and algorithms, more complex strategic behaviours that can influence human decisions and actions during an interaction, remains largely open. To address this issue, this thesis introduces the problem of decision shaping in strategic interactions between humans and robots, where a robot seeks to lead, without however forcing, an interacting human partner to a particular state. Our approach to this problem is based on a combination of statistical modeling and synthesis of demonstrated behaviours, which enables robots to efficiently adapt to novel interacting agents. We primarily focus on interactions between autonomous and teleoperated (i.e. human-controlled) NAO humanoid robots, using the adversarial soccer penalty shooting game as an illustrative example. We begin by describing the various challenges that a robot operating in such complex interactive environments is likely to face. Then, we introduce a procedure through which composable strategy templates can be learned from provided human demonstrations of interactive behaviours. We subsequently present our primary contribution to the shaping problem, a Bayesian learning framework that empirically models and predicts the responses of an interacting agent, and computes action strategies that are likely to influence that agent towards a desired goal. We then address the related issue of factors affecting human decisions in these interactive strategic environments, such as the availability of perceptual information for the human operator. Finally, we describe an information processing algorithm, based on the Orient motion capture platform, which serves to facilitate direct (as opposed to teleoperation-mediated) strategic interactions between humans and robots. Our experiments introduce and evaluate a wide range of novel autonomous behaviours, where robots are shown to (learn to) influence a variety of interacting agents, ranging from other simple autonomous agents, to robots controlled by experienced human subjects. These results demonstrate the benefits of strategic reasoning in human-robot interaction, and constitute an important step towards realistic, practical applications, where robots are expected to be not just passive agents, but active, influencing participants.
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Rhim, Sungsoo. "Limitations and improvements of time-delay command shaping filters for flexible machine control." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/18876.
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Yu, Yang. "Synchronous Machine for Unidirectional Application." Thesis, KTH, Elektrisk energiomvandling, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105832.
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This master thesis investigates the possibilities for performance improvements of synchronous machines with unidirectional application.The literature review part presents theories and applications of asymmetrical machine. Four categories regarding asymmetrical machine, namely mixed pole, saturation mitigation, pole shifting and asymmetrical pole shaping, are summarized. It is shown that asymmetrical concept offers characteristic improvement in one or both rotational directions. A field winding synchronous model was used in FEM simulation (FLUX 2D). Armature reaction effecton this machine is investigated. It is found that armature reaction has different effects with varying current angle.Two ideas regarding asymmetrical pole shaping are investigated. First of all, pole shoe cutting idea is investigated. It leads to increased airgap length and less output torque. Secondly, progressive airgap idea shows reduced armature reaction effect and improved power factor, but higher torque ripple.Furthermore, an improved idea is suggested to reduce the torque ripple. Performance improvement by assisted permanent magnet is also studied. Four ideas of this field are investigated. It is found that permanent magnet can be used to reduce saturation, improve power factor and output torque. The reasons for limited improvements are analyzed.
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Rezayi, Khoshdarregi Mohammad. "Vibration avoidance and contour error compensation in high speed five-axis machine tools using command shaping techniques." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43210.
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The present machine tools travel at high velocities with large acceleration and jerk, which creates large inertial loads with wide frequency content, resulting in excitation of the natural frequencies of the machine. This thesis presents a command shaping module which avoids structural vibrations and improves contouring accuracy in five-axis machine tools.
Inertial-induced vibrations of feed drives are avoided by applying a sequence of input shaping impulses on the axis position commands as a function of natural frequencies of the machine. Input shapers block those harmonics of the command which can excite the modes of the machine. While command shaping avoids the excitation of transient vibrations caused by inertial loads, it introduces a time delay which increases the contouring errors in multi-axis motion control systems.
Although input shaping can effectively avoid vibrations, it distorts the toolpath in multi-axis contouring due to added time delays. The distortion increases the contour errors caused by the limited bandwidth of axis servo drives, resulting in relatively large geometric errors and violation of the required tolerance. The transfer function of the axis drives and kinematic configuration of the machine tool are used to estimate the contouring error, which is decoupled into axis components, and compensated prior to sending the position commands to each drive.
The proposed integrated input shaping and contour error compensation module can be applied on any arbitrary trajectory, and the shaped-compensated command results in vibration-free and accurate contouring of the desired path. The input shaping and contouring error compensation techniques introduced in the thesis have been experimentally validated in single, two and five axis machine tools.
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Wondergem, Ashley, and Monika Ivantysynova. "The Impact of Micro-Surface Shaping of the Piston on the Piston/Cylinder Interface of an Axial Piston Machine." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200169.
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Axial piston machines of the swashplate type are commonly used in various hydraulic systems and with recent developments in displacement control, it is essential to maximize their efficiency further reducing operation costs as well as improving performance and reliability. This paper reports findings of a research study conducted for the piston-cylinder interface utilizing a novel fluid structure thermal interaction model considering solid body deformation due to thermal and pressure effects in order to accurately predict the transient fluid film within the gap. A large reduction in energy dissipation is possible due to reduced clearances allowable due to the surface shaping of the piston resulting in a reduction in leakage. From this study, it is shown that surface shaping of the piston in combination with a reduced clearance is not only beneficial by improving the efficiency of a machine, but also increases the reliability and the performance of the machine as the load support is enhanced.
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Barker, David W. "Machine Tool Spare Parts Provisioning for Manufacturers: A Study and Application for Industries Engaged in Aluminum Cutting and Shaping." Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc331260/.
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This study identifies the concepts of reliability, cost of downtime, cost of spare parts, and procurement lead time as the four key moderators of spare parts availability. These concepts are used to establish a model to manage spare parts inventories. Reliability was assessed in terms of developing failure predictions for major component categories. Cost of downtime was evaluated by identifying various methods for determining costs associated with downtime. Cost of spare parts was examined to find correlations with economic indicators. These correlations were used to predict future price movements. Yearly changes in lead time were identified and correlated with economic indexes to develop movement predictability.
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Mi, Yongcui. "Novel beam shaping and computer vision methods for laser beam welding." Licentiate thesis, Högskolan Väst, Avdelningen för produktionssystem (PS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-16970.
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Laser beam welding has been widely applied in different industrial sectors due to its unique advantages. However, there are still challenges, such as beam positioning in T-joint welding, and gap bridging in butt joint welding,especially in the case of varying gap width along a joint. It is expected that enabling more advanced control to a welding system, and obtaining more in-depth process knowledge could help to solve these issues. The aim of this work is to address such welding issues by a laser beam shaping technology using a novel deformable mirror together with computer vision methods and also to increase knowledge about the benefits and limitations with this approach. Beam shaping in this work was realized by a novel deformable mirror system integrated into an industrial processing optics. Together with a wave front sensor, a controlled adaptive beam shaping system was formed with a response time of 10 ms. The processes were monitored by a coaxial camera with selected filters and passive or active illumination. Conduction mode autogenous bead-on-plate welding and butt joint welding experiments have been used to understand the effect of beam shaping on the melt pool geometry. Circular Gaussian, and elliptical Gaussian shapes elongated transverse to and along the welding direction were studied. In-process melt pool images and cross section micrographs of the weld seams/beads were analyzed. The results showed that the melt pool geometry can be significantly modified by beam shaping using the deformable mirror. T-joint welding with different beam offset deviations relative to the center of the joint line was conducted to study the potential of using machine learning to track the process state. The results showed that machine learning can reach sufficient detection and estimation performance, which could also be used for on-line control. In addition, in-process and multidimensional data were accurately acquired using computer vision methods. These data reveal weaknesses of current thermo-fluid simulation model, which in turn can help to better understand and control laser beam welding. The obtained results in this work shows a huge potential in using the proposed methods to solve relevant challenges in laser beam welding.Lasersvetsning används i stor utsträckning i olika industrisektorer på grund av dess unika fördelar. Det finns emellertid fortfarande utmaningar, såsom rätt positionering av laserstrålen vid genomträngningssvetsning av T-fogar och hantering av varierande spaltbredd längs fogen vid svetsning av stumfogar. Sådana problem förväntas kunna lösas med avancerade metoder för automatisering, metoder som också förväntas ge fördjupade kunskaper om processen. Syftet med detta arbete är att ta itu med dessa problem med hjälp av en teknik för lasereffektens fördelning på arbetsstycket, s.k. beam shaping. Det sker med hjälp av en ny typ av i realtid deformerbar spegel tillsammans med bildbehandling av kamerabilder från processen. För- och nackdelar med detta tillvägagångssätt undersöks.Beam shaping åstadkoms med hjälp av ny typ av deformerbart spegelsystem som integreras i en industriell processoptik. Tillsammans med en vågfrontsensor bildas ett adaptivt system för beam shaping med en svarstid på 10 ms. Processen övervakas av en kamera linjerad koaxialt med laserstrålen. För att kunna ta bilder av svetspunkten belyses den med ljus av lämplig våglängd, och kameran är försedd med ett motsvarande optiskt filter. Försök har utförts med svetsning utan tillsatsmaterial, direkt på plåtar, svetsning utan s.k. nyckelhål, för att förstå effekten av beam shaping på svetssmältans geometri. Gauss fördelade cirkulära och elliptiska former, långsträckta både tvärs och längs svetsriktningen har studerats. Bilder från svetssmältan har analyserats och även mikrostrukturen i tvärsnitt från de svetsade plåtarna. Resultaten visar att svetssmältans geometri kan modifieras signifikant genom beam shaping med hjälp av det deformerbara spegelsystemet. Genomträngningssvetsning av T-fogar med avvikelser relativt foglinjens centrum genomfördes för att studera potentialen i att använda maskininlärning för att fånga processens tillstånd. Resultaten visade att maskininlärning kan nå tillräcklig prestanda för detektering och skattning av denna avvikelse. Något som också kan användas för återkopplad styrning. Flerdimensionell processdata har samlats i realtid och analyserats med hjälp av bildbehandlingsmetoder. Dessa data avslöjar brister i nuvarande simuleringsmodeller,vilket i sin tur hjälper till med att bättre förstå och styra lasersvetsning.Resultaten från detta arbete uppvisar en god potential i att använda de föreslagna metoderna för att lösa relevanta utmaningar inom lasersvetsning.
Till licentiatuppsats hör 2 inskickade artiklar, som visas inte nu.
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Sorensen, Khalid Lief. "Operational Performance Enhancement of Human Operated Flexible Systems." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24773.
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Recent decades have been witness to explosive leaps in manufacturing productivity. Advances in communication technology, computing speed, control theory, and sensing technology have been significant contributors toward the increased productivity and efficiency that industry has exhibited. The continued growth of technological equipment and engineering knowledge challenges engineers to fully utilize these advancements in more sophisticated and useful automation systems.
One such application involves enhancing bridge and gantry crane operation. These systems are used throughout the globe, and are critical aspects of industrial productivity. Consequently, improving the operational effectiveness of cranes can be extremely valuable.
Effective control of cranes can be largely attributed to two distinct, but related aspects crane manipulation: 1) the expertise of operators, which are responsible for issuing commands to the structures, and 2) the dynamic properties of cranes, which influence how the structures respond to issued commands. Accordingly, the operational efficiency of cranes can be influenced by changing both the way that operators issue commands to cranes, and also how the crane responds to issued commands.
This thesis is concerned with dynamic control theory of flexible machines, and human/machine interaction, especially as these areas relate to industrial crane control. In the area of dynamic control, this thesis investigates control strategies that are specifically suited for use on systems that possess common actuator nonlinearities, like saturation, rate limiting, dead-zone, backlash, and finite-state actuation. In the area of human/machine interaction, this thesis investigates the effects of different crane interface devices on the operational efficiency of cranes.
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Maleki, Ehsan A. "Control of human-operated machinery with flexible dynamics." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50305.
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Heavy-lifting machines such as cranes are widely used at ports, construction sites, and manufacturing plants in a variety of material-transporting applications. However, cranes possess inherent flexible dynamics that make fast and precise operation challenging. Most cranes are driven by human operators, which adds another element of complexity. The goal of this thesis is to develop controllers that allow human operators to easily and efficiently control machines with flexible dynamics. To improve the ease of human operation of these machines, various control structures are developed and their effectiveness in aiding the operator are evaluated. Cranes are commonly used to swing wrecking balls that demolish unwanted structures. To aid the operator in such tasks, swing-amplifying controllers are designed and their performance are evaluated through simulations and experiments with real operators. To make maneuvering of these machines in material-transporting operations easier, input-shaping control is used to reduce oscillation induced by operator commands. In the presence of external disturbances, input shaping is combined with a low-authority feedback controller to eliminate unwanted oscillations, while maintaining the human operator as the primary controller of the machine. The performance and robustness of the proposed controllers are thoroughly examined via numerical simulations and a series of experiments and operator studies on a small-scale mobile boom crane and a two-ton dual-hoist bridge crane.
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Rangra, Subeer. "Performance shaping factor based human reliability assessment using valuation-based systems : application to railway operations." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2375/document.
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L'homme reste l'un des éléments essentiels des opérations de transport modernes. Les méthodes d'analyse de la fiabilité humaine (HRA) fournissent une approche multidisciplinaire pour évaluer l'interaction entre les humains et le système. Cette thèse propose une nouvelle méthodologie HRA appelée PRELUDE (Performance shaping factor based human REliability assessment using vaLUation-baseD systems). Les facteurs de performance sont utilisés pour caractériser un contexte opérationnel dangereux. Le cadre de la théorie des fonctions de croyance et des systèmes d'évaluation (VBS) utilise des règles mathématiques pour formaliser l'utilisation de données d'experts et la construction d'un modèle de fiabilité humaine, il est capable de représenter toutes sortes d'incertitudes. Pour prédire la probabilité d'erreur humaine dans un contexte donné, et de fournir une remontée formelle pour réduire cette probabilité. La deuxième partie de ce travail démontre la faisabilité de PRELUDE avec des données empiriques. Un protocole pour obtenir des données à partir de simulateurs, et une méthode de transformation et d'analyse des données sont présentés. Une campagne expérimentale sur simulateur est menée pour illustrer la proposition. Ainsi, PRELUDE est en mesure d'intégrer des données provenant de sources (empiriques et expertes) et de types (objectifs et subjectifs) différents. Cette thèse aborde donc le problème de l'analyse des erreurs humaines, en tenant compte de l'évolution du domaine des méthodes HRA. Elle garde la facilité d'utilisation de l'industrie ferroviaire, fournissant des résultats qui peuvent facilement être intégrés avec les analyses de risques traditionnelles. Dans un monde de plus en plus complexe et exigeant, PRELUDE fournira aux opérateurs ferroviaires et aux autorités réglementaires une méthode permettant de s'assurer que le risque lié à l'interaction humaine est compris et géré de manière appropriée dans son contexteHumans are and remain one of the critical constituents of modern transport operations. Human Reliability Analysis (HRA) methods provide a multi-disciplinary approach: systems engineering and cognitive science methods to evaluate the interaction between humans and the system. This thesis proposes a novel HRA methodology acronymed PRELUDE (Performance shaping factor based human REliability assessment using vaLUation-baseD systEms). Performance shaping factors (PSFs) are used to characterize a dangerous operational context. The proposed framework of Valuation-based System (VBS) and belief functions theory (BFT) uses mathematical rules to formalize the use of expert data and construction of a human reliability model capable of representing all kinds of uncertainty. PRELUDE is able to predict the human error probability given a context, and also provide a formal feedback to reduce the said probability. The second part of this work demonstrates the feasibility of PRELUDE with empirical data from simulators. A protocol to obtain data, a transformation and data analysis method is presented. An experimental simulator campaign is carried out to illustrate the proposition. Thus, PRELUDE is able to integrate data from multiple sources (empirical and expert) and types (objective and subjective). This thesis, hence address the problem of human error analysis, taking into account the evolution of the HRA domain over the years by proposing a novel HRA methodology. It also keeps the rail industry’s usability in mind, providing a quantitative results which can easily be integrated with traditional risk analyses. In an increasingly complex and demanding world, PRELUDE will provide rail operators and regulatory authorities a method to ensure human interaction-related risk is understood and managed appropriately in its context
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Peng, Chen-Chih. "Methods for improving crane performance and ease of use." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50343.
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Cranes are widely used in material-handling and transportation applications, e.g. in shipyards, construction sites, and warehouses. As they are critical to the economic vitality of modern-day industries, improving crane performance and ease of use are important contributors to industrial productivity, low production costs, and workplace safety.
In a typical crane operation, a payload is lifted, moved to its destination, and then lowered into place. This dissertation aims to improve crane performance and reduce task difficulty for the human operator in the movements mentioned above, namely: 1) Moving payloads laterally in the horizontal plane, 2) Lifting payloads off the ground, and 3) Lowering or laying down payloads on the ground.
The design of a novel and intuitive human-machine control interface is the focus for improving operations that involve moving payloads laterally. The interface allows operators to drive a crane by simply moving a hand-held device through the desired path. The position of the device, which is tracked by sensors, is used to generate command signals to drive the crane. This command is then input-shaped such that payload oscillations are greatly reduced, making it much easier for the operator to drive the crane. Several facets of this crane control method are examined, such as control structure and stability, usability contexts, modes of operation, and quantitative measures (by means of human operator studies) of performance improvements over standard crane control interfaces.
Lifting up a payload can be difficult for the operator, if the hoist is not properly centered above the payload. In these potentially dangerous and costly ``off-centered" lifts, the payload may slide on the ground and/or oscillate in the air after it is hoisted. Newtonian and Coulomb friction models that focus on the stiction-sliding-separation contact dynamics are derived and experimentally verified to study off-centered lifts. Then, with the goal of aiding operators during lift operations, simple but practical, self-centering solutions are proposed and implemented.
Laying down or lowering a payload to the ground can also be challenging for operators in certain situations. For example, laying down a long, slender payload from a vertical orientation in the air, to a horizontal position on a flat surface. If the operator does not properly coordinate the motions of the crane in the vertical and horizontal directions simultaneously, then the potential hazards that may occur during these operations include: 1) slipping of the pivot about which the payload rotates, leading to sudden and dangerous payload movements; and 2) excessive hoist cable angles that lead to ``side-pull" problems. Newtonian and Coulomb friction models are derived to describe this lay-down scenario. The forces and motions experienced by the payload are then used to determine the motion trajectories that the crane and payload should follow to execute a successful lay-down maneuver.
Finally, a special chapter is included to address the oscillation control of systems that have on-off nonlinear actuators, such as cranes powered by relay-controlled circuits. Due to their simplicity, ruggedness, and long service life, this type of crane can be commonly found in older factories or in applications where precise motion control is not a strict requirement. However, controlling payload oscillations on this type of crane is challenging for two reasons: 1) Relays that can only be turned on or off allow for only limited control over the crane velocity; and 2) These cranes typically have nonlinear asymmetrical acceleration and deceleration properties. Methods are derived for determining the relay switch-times that move single-pendulum and double-pendulum payloads with low residual oscillations.
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Pergolini, Diego. "Reinforcement Learning: un caso di studio nell'ambito della Animal-AI Olympics." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19415/.
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Il Reinforcement Learning (RL) ha ottenuto grandi risulti negli ultimi anni, superando l'uomo nei giochi Atari, nel GO ed in e-sports come Starcraft e Dota2. Può però il RL affrontare sfide complesse che richiedono varie abilità cognitive per superare brillantemente situazioni complesse e variegate, come potrebbe fare un animale o un umano? Per dimostrarlo sarà necessario un benchmark robusto e significativo, come la competizione Animal-AI Olympics. I suoi organizzatori hanno messo a disposizione un'arena in cui un agente si muoverà ed interagirà con vari oggetti, con l’obiettivo di procurarsi del cibo. La competizione include 10 categorie di test, ognuna atta a dimostrare il possesso di una certa capacità cognitiva. L’agente avrà due input sensoriali: visione monoculare e percezione della propria velocità. In questo lavoro si è utilizzato PPO come algoritmo di RL, semplificando i dati della visione considerando solo i colori legati a stimoli positivi e negativi e dividendo l’immagine in quadranti, così da avere input più significativi. L'addestramento è stato coadiuvato da curriculum learning e reward shaping, unitamente alla definizione di scenari istruttivi per l’agente. Con il primo si è voluto insegnare all'agente dapprima la relazione fra oggetti e punteggio ricevuto, per poi addestrarlo ad agire in ambiente più complessi. Con il secondo, qui basato sulle velocità percepite, si è spinto PPO a trovare strategie intelligenti per esplorare l’arena ed ottenere premi. Sono state inoltre condotte delle sperimentazioni su approcci multi-modello, analizzandone i risultati ottenuti. Alcune indagini preliminari hanno riguardato il problema dello SLAM. Il risultato finale è stato un 9° posto su 64 partecipanti, oltre ad un premio sulla categoria 2 (esibizione di preferenze). I risultati dimostrano la bontà delle scelte intraprese sopratutto nell'esibire abilità cognitive più basilari, motivo per cui il percorso per arrivare ad un modello davvero generale è ancora lungo.
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Fortgang, Joel D. "Combined Mechanical and Command Design for Micro-Milling Machines." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10430.
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The utilization of micro-scale technologies is limited by the speed of their manufacture. Micro-milling is one particular technology used to manufacture micro-scale parts which could benefit extensively from an increase in throughput. Micro-milling involves a rotating cutter slightly thicker than a human hair removing material while spinning at speeds often over one hundred thousand revolutions per minute.
An obvious solution to the throughput bottleneck is to move current micro-mills faster using existing technology; however, simply increasing the operational speed of existing micro-mills will lead to vibration and trajectory following problems. If a micro-mill cannot be positioned precisely, then part tolerances cannot be maintained. Thus any increase in throughput would be counterproductive in terms of overall performance.
This dissertation presents techniques to improve the performance of micro-mills, as well as other flexible machines. Theses improvements are possible through the utilization of the vibration suppression scheme of input shaping. By thoughtfully altering the commands sent to flexible systems, their vibration can be significantly reduced. Input shaping was effectively applied to an existing micro-mill, which improved part tolerances and increased operational speed. However, at extremely high speeds, traditional input shaping is not effective at following complicated trajectories. Therefore, new input shaping techniques were developed specifically for trajectory tracking of extremely fast motions on micro-mills and other flexible systems. Often machines cannot achieve these high speeds while maintaining their accuracy because of the mechanical design of the machines themselves. If the mechanical design of micro-mills and other machines consider flexible and lightweight design alternatives that utilize input shaping for vibration suppression instead of stiff and heavy designs, then faster machine motion will be possible. By considering input shaped flexible systems as part of traditional mechanical design processes, these flexible solutions allow vast performance improvement. Specifically, embodiment design can be improved through consideration of input shaping performance requirements. Through these advancements, this dissertation improves the design, control, and performance of micro-mills and other flexible machines.
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Suay, Halit Bener. "Reinforcement Learning from Demonstration." Digital WPI, 2016. https://digitalcommons.wpi.edu/etd-dissertations/173.
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Off-the-shelf Reinforcement Learning (RL) algorithms suffer from slow learning performance, partly because they are expected to learn a task from scratch merely through an agent's own experience. In this thesis, we show that learning from scratch is a limiting factor for the learning performance, and that when prior knowledge is available RL agents can learn a task faster. We evaluate relevant previous work and our own algorithms in various experiments. Our first contribution is the first implementation and evaluation of an existing interactive RL algorithm in a real-world domain with a humanoid robot. Interactive RL was evaluated in a simulated domain which motivated us for evaluating its practicality on a robot. Our evaluation shows that guidance reduces learning time, and that its positive effects increase with state space size. A natural follow up question after our first evaluation was, how do some other previous works compare to interactive RL. Our second contribution is an analysis of a user study, where na"ive human teachers demonstrated a real-world object catching with a humanoid robot. We present the first comparison of several previous works in a common real-world domain with a user study. One conclusion of the user study was the high potential of RL despite poor usability due to slow learning rate. As an effort to improve the learning efficiency of RL learners, our third contribution is a novel human-agent knowledge transfer algorithm. Using demonstrations from three teachers with varying expertise in a simulated domain, we show that regardless of the skill level, human demonstrations can improve the asymptotic performance of an RL agent. As an alternative approach for encoding human knowledge in RL, we investigated the use of reward shaping. Our final contributions are Static Inverse Reinforcement Learning Shaping and Dynamic Inverse Reinforcement Learning Shaping algorithms that use human demonstrations for recovering a shaping reward function. Our experiments in simulated domains show that our approach outperforms the state-of-the-art in cumulative reward, learning rate and asymptotic performance. Overall we show that human demonstrators with varying skills can help RL agents to learn tasks more efficiently.
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Wang, Kai. "Novel rotor shaping and stator winding of permanent magnet brushless AC machines." Thesis, University of Sheffield, 2013. http://etheses.whiterose.ac.uk/5092/.
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Guy, Katherine. "A design perspective on shaping possibilities with new technology v bed knitting machines." Thesis, Nottingham Trent University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250446.
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Chen, Changhe. "Robot feasibility for trimming and shaping field-grown nursery plants." Connect to resource, 1987. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1201633112.
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Manning, Raymond Charles. "Improving the control of two-mode flexible systems with input shaping." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22566.
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Pridgen, Brice. "Comparison of polynomial profiles and input shaping for industrial applications." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39547.
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Command shaping creates reference commands that reduce residual vibrations in a flexible system. This thesis examines the use of command shaping for flexible system control in three industrial applications: cam-follower systems, sloshing liquids, and cherrypickers. One common type of command shaping is command smoothing which creates a smooth transition between setpoints. A specific type of command smoothing used in cam-follower systems is the polynomial profile. An alternative technique to reduce vibration in flexible systems is input shaping. In this thesis, input-shaped commands are compared to polynomial profiles for applications requiring both vibration suppression and fast motion. Simulation and experimental results show that input shaping is faster than polynomial profiles and provides a simple approach to suppressing residual vibration.
Secondly, significant experimental contributions have been made in the area of slosh control. The oscillation of liquids in a container can cause liquid spillage or can cause stability issues, especially in space vehicles. In the past, a number of control techniques have been proposed, but only a few recommend the use of input shaping. This thesis describes the use of command shaping to limit slosh. Results are supported by numerical and experimental testing. Input-shaped commands reduce residual slosh amplitude compared to unshaped commands and polynomial profiles. Input-shaped commands can also accommodate uncertainties and changes in the sloshing frequencies.
Lastly, a small-scale cherrypicker was constructed to study the use of input-shaping control on these types of aerial lifts. Cherrypickers have flexible dynamic effects that can cause dangerous and life-threatening situations. To study this class of machines and to provide future students an experimental testbed, several design criteria were established before construction began. The resulting machine achieved most design objectives, including a simple-to-use graphical user interface and accurate state measurements. Robust input-shaping controllers were implemented to limit endpoint vibration. The design of the cherrypicker is discussed and experimental results are reported.
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Bourquin, Yannyk Parulian Julian. "Shaping surface waves for diagnostics." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/4167/.
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Infectious diseases continue to kill millions of people every year and are a significant burden on the socio-economic development of developing countries. After many years of international policy aimed at containing diseases, it has recently become an explicit aim to move towards elimination of infectious diseases. However, if this is to occur, it will be necessary to have highly eficacious diagnostic tools to ensure infected individuals are identified and treated. However, the diagnosis of infectious diseases in the developed and developing world requires the full integration of complex assays in easy-to-use platforms with robust analytical performances at low cost. Many relevant bioanalytical technologies have been developed for use in laboratories and clinics, including the current gold standard for the diagnosis of tuberculosis and malaria. The miniaturization and integration of complex functions into lab-on-a-chip (LOC)technologies using microfluidics have only had limited success in translating diagnosis assays out of a centralized laboratory to point-of-care (POC) settings, because they still remain constrained due to chip interconnection and they are either not likely to go out of research laboratories or are not appropriate for low resource settings. In this thesis, a new microfluidic platform was developed that reduced the dependency of the diagnostic procedure on large laboratory instruments providing simplicity of use, enabling the patient sample to be processed and diagnosed on a low cost, disposable biochip. Surface acoustic wave (SAW) devices, which are commonly used in mobile phone technologies, were adapted to provide controlled microfluidic functions by shaping the SAW using particular designs of electrodes and phononic structures. The control of lateral positioning of the SAW was demonstrated using a slanted finger interdigitated transducer (IDT) in a frequency tuneable manner allowing microfluidic functions such as mixing, moving and merging, sequentially performed using a single IDT both on the substrate and on a disposable chip. Alternatively, phononic bandgaps were designed to break the symmetry of the SAW in a tuneable manner and gradient index phononic crystals (GRIN-PC) lenses were designed to focus the SAW and successfully increased the amplitude of the wave by a factor 3 while the focal position could be tuned with the frequency. The potential of these techniques was demonstrated by controlling the amplitude and direction of water jet towers by the use of a phononic horn structure that allowed the enhancement of energy at defined positions and by propelling and directing a macrometer scale object in water using a slanted IDT. As proof of concepts of diagnostic devices for the developing world, an immunoassay for tuberculosis using only mobile phone technologies (SAW, light-emitting diode(LED) and complementary metaloxidesemiconductor (CMOS) camera) was demonstrated with a limit of detection of 1 pM, which is the limit required in an interferon-release assay. This limit of detection was only achievable because of the ability of SAW to increase the mixing and to reduce the non-specific binding. Furthermore, a method to enrich malaria infected cells, based on SAW and isopycnic gradient, was also demonstrated and showed an enrichment up to 100x in the equivalent of a fingerprick of blood in 3 seconds. This technique will allow to reduce the limit of detection of the current gold standard. This platform not only opens a clear road toward POC diagnostics due to its size, cost, versatility and ease in integration, but has also the potential to provide useful tools in laboratory settings for large scale, high throughput technologies.
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Islam, Mohammed Rakibul. "Cogging Torque, Torque Ripple and Radial Force Analysis of Permanent Magnet Synchronous Machines." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1239038005.
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Babu, Sailesh. "A material based approach to creating wear resistant surfaces for hot forging." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1101836555.
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Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xxii, 185 p.; also includes graphics (some col.). Includes bibliographical references (p. 178-185).
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Liao, Shiou-Ho, and 廖修鶴. "Development of Configuration Evaluation System for Multi-Axis Machine Tool Utilizing Form-Shaping Function." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/21648005068699119431.
Full textAbstract:
碩士國立成功大學
機械工程學系碩博士班
97
Multi-axes machine tool plays an important role in manufacturing recently, especially in mold surface and aerospace product. It could not only be a rapid and accurate tool but also reduces errors in workpiece set-up. However, in general manufacturing processes, engineers are usually not able to determine the set-up orientation before planning of toolpath so must be considerated about the rotary and traverse range of machine tool after the toolpath has generated. If a system could used to help CAPP engineers to increase the efficiency of process development, the problem can be sloved. In this research, homogeneous coordinate transformation and configuration synthesis are used to develop an evaluation system for choosing machine tool and workpiece set-up. First, the configurations of 3,4and 5-axis machine tools were synthesized afterward, a form-shaping function is used to construct its configuration. The last step is to solve for the movement of every component according to inverse kinematics, evaluation configuration by cutter location file, and modified workpiece orientation by using spherical coordinate correspond to homogeneous coordinate transformation matrix. This thesis proposed a method of manufacturability evaluation to provide CAPP engineers in toolpath planning, It could reduce the time required for feedback which is determined by modifying workpiece orientation. The results of the proposed method may provide a recommended choise of configuration to the engineers.
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"Filtering Techniques for Improving Radio-Frequency Identification Machine Control." Master's thesis, 2012. http://hdl.handle.net/2286/R.I.14919.
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abstract: Human operators have difficulty driving cranes quickly, accurately, and safely because of the slow response of heavy crane structures, non-intuitive control interfaces, and payload oscillations. Recently, a novel hand-motion crane control system has been proposed to improve performance by coupling an intuitive control interface with an element that reduces the complex oscillatory behavior of the payload. Hand-motion control allows operators to drive a crane by simply moving a hand-held radio-frequency tag through the desired path. Real-time location sensors are used to track the movements of the tag and the tag position is used in a feedback control loop to drive the crane. An input shaper is added to eliminate dangerous payload oscillations. However, tag position measurements are corrupted by noise. It is important to understand the noise properties so that appropriate filters can be designed to mitigate the effects of noise and improve tracking accuracy. This work discusses implementing filtering techniques to address the issue of noise in the operating environment. Five different filters are used on experimentally-acquired tag trajectories to reduce noise. The filtered trajectories are then used to drive crane simulations. Filter performance is evaluated with respect to the energy usage of the crane trolley, the settling time of the crane payload oscillations, and the safety corridor of the crane trajectory. The effects of filter window lengths on these parameters are also investigated. An adaptive filtering technique, namely the Kalman filter, adapts to the noise characteristics of the workspace to minimize the tag tracking error and performs better than the other filtering techniques examined.Dissertation/Thesis
M.S. Bioengineering 2012
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Huang, shui-tien, and 黃水田. "Application Of A Recurrent Neural Fuzzy Network To Mold Temperature Control Of A Rubber Shoot Shaping Machine." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/51193374700583101966.
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碩士國立中興大學
電機工程學系
92
Abstract Based on the direct inverse control approach, temperature control by TSK-type recurrent neural fuzzy network (TRNFN) controller is proposed in this thesis. The mold temperature control of a shoot shaping machine system is experimented by using TRNFN controller based direct inverse control. There are no rules initially in TRNFN; they are constructed by concurrent structure and parameter learning. The TRNFN has the following advantages： (1) mathematical model and system order are not required. (2) powerful learning ability, which can model the inverse of the plant accurately. (3) on-line learning ability, i.e. the TRNFN can deal with unpredictable changes in the control environment. In the experiment, we will show that without reassigning the input variables in TRNFN, a good control performance is achieved even when the sampling period changes. The same experiment is also performed by PI and fuzzy controllers. From comparisons, the aforementioned advantages of TRNFN have been verified.
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Kuan-AnChen and 陳冠安. "Investigation on Effect of Assembly Error of Five-axis Machine Tool on Volumetric Error Using Form-Shaping Function." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/39250941773057596794.
Full textAbstract:
碩士國立成功大學
機械工程學系碩博士班
98
Five-axis machine tool is widely used in machining freeform surfaces. Accuracy of machine tool becomes one of the most critical considerations for both manufacturer and user. The geometric errors of machine tool contribute to the major part of tool position error. Many previous works have established mathematical models for analyzing the errors of machine tool, in order to allocating errors in design stage or to compensating errors after measurement. However, the effect of error terms in the model was seldom studied and clearly derived. It plays an important role in either error allocation or error compensation. Therefore, the purpose of this paper is to present a mathematical analysis method for investigating on the effect of each translational and angular error terms on the tool center point error of the machine tool based on form-shaping function. This model not only is clear in physical meaning but also easy to identify the errors which can be compensated directly from the property of matrix. Numerical values are substituted for error terms to perform the sensitivity analysis. The contribution of each error term to the volumetric error has been compared. Monte Carlo method is used to simulate the interval values. Finally, a case study is given for analyzing geometric errors due to assembly errors of machine tool using the presented methodology. An evaluation interface for machine tool designer or user has been developed. It provides for the system user to analyze the different configuration of machine tool and suggest the one with minimum error of tool center point position. It can be used as a tool in assembly tolerance design of machine tool according to a given workpiece.
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Hui-LingHsu and 許慧玲. "Value Co-creation Perspective on Shaping Co-Creation Platform for the Injection Molding Machine : A Case Study of Company F." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/cn9k76.
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Pan, Kai-Ming, and 潘楷明. "Research on the Development of a Precision Meso-Scale Machine Tool and the Shaping Process Using a Single Crystal Diamond Tool." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/93104878691396865999.
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博士國立臺灣科技大學
機械工程系
103
The objective of this research is to develop a mso-scale machine tool which is mainly constructed by a XY coplanar stage and a Z-axis diamond tool clamping mechanism supported by a co-axial counter-balance mechanism, and to investigate the shaping process using a single crystal diamond tool. The developed machine tool was actuated by the Galil motion controller for the precision motion control of the ultrasonic motors. Regarding the control interface, a set of software programmed using Visual Basic 6.0 was used to control the Galil motion controller. Based on the test results, the closed loop mseo-scale machine tool was able to provide precision positioning with the travel of 20 mm along XY-axis and the travel of 14 mm along Z-axis. By utilizing the Galil motion controller with the PID closed-loop control, the positioning capability of X-axis was about 2 nm, Y-axis was about 2 nm, and Z-axis was about 100 nm. Base on the liner displacement compensation results, the system uncertainty along X-axis was 5.039 μm, Y-axis was 2.496 μm, and Z-axis was 6.449 μm. A circular positioning test with the radius of 2 mm was tested, and the overall roundness error was about 4.745 μm. The diamond shaping process has been applied to fabricate the micro V-grooves. The result shows that the optimal depth of cut for bulk metallic glass material is 40 μm. The micro V-grooves and the micro pyramid cutting tests of the polished oxygen free copper using a single crystal diamond tool have been tested on the meso-scale machine tool. The measured cutting forces for the depth of cut of 5, 10, 15 μm were 1.2 N, 1.6 N and 2.4 N, respectively.
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(10135868), Meike H. Ernst. "Enabling High-Pressure Operation with Water for the Piston-Cylinder Interface In Axial Piston Machines." Thesis, 2021.
Find full textAbstract:
Water is inflammable, non-toxic, environmentally friendly--- desirable traits, for a hydraulic fluid. However, its extremely low viscosity diminishes the load-bearing and sealing capacity of lubricating interfaces. Case in point: axial piston machines of swash plate design are compact, highly efficient positive displacement machines at the heart of hydraulic systems in forestry, construction, aerospace, and agricultural equipment, as well as industrial applications (presses, etc.); however, the three main lubricating interfaces decisive to the performance of such units in terms of both component life and efficiency are challenged by the use of water as working fluid. Especially during high-pressure operation, this low-viscosity lubricant can cause the these interfaces to fail in carrying the imposed load, resulting in severe wear, or even pump failure. The piston-cylinder interface is particularly challenging to design for water because it stands under obligation to carry the heavy side load that acts on the pistons of these machines, which increases with operating pressure. Furthermore, the architecture of axial piston machines of swash plate design does not allow this interface to be hydrostatically balanced.
Through the development of a methodology that separates the fluid pressure fields of the three main lubricating interfaces of axial piston machines into their hydrostatic and hydrodynamic components, the present work enables a direct comparison of these interfaces in terms of how they support load. A case study of a 75 cc unit running on hydraulic oil conducted via this methodology at three different operating conditions (low pressure/low speed, low pressure/high speed, and high pressure/low speed) demonstrates that in the piston-cylinder interface, the force from hydrostatic pressure reaches such high magnitudes over the high-pressure stroke that less than half of it is needed to counter the load. The excess force from hydrostatic pressure then becomes the load. Consequentially, hydrodynamic pressure must counter a force from hydrostatic pressure that exceeds the original load. In the other two interfaces, by contrast, over half the load is being carried by hydrostatic pressure, thus significantly diminishing the amount of hydrodynamic pressure the interfaces are required to generate in order to achieve full load support. Moreover, nearly all of the moment on the piston is countered by hydrodynamic pressure, while less than half of the moment on the block is countered by hydrodynamic pressure, and the moment on the slipper is negligible by comparison.
While this case study only investigates one pump, it shows how critical hydrodynamic pressure can be to load support in the piston-cylinder interface. The use of a low-viscosity fluid, e.g. water, reduces the hydrodynamic pressure that is generated in this interface, which, at challenging operating conditions, can lead to metal-to-metal contact. However, the performance of the interface can be improved via micro surface shaping, i.e. by giving the surface of the piston, or the bore that it moves through, a shape on the order of microns in height. The aim of present work is to pursue design trends leading to surface shapes that will enable this interface to function at higher pressures than currently achievable.
This pursuit takes the form of systematic virtual design studies, an optimization procedure, and an algorithm developed specifically for tailoring the bore surfaces through which the pistons travel to piston tilt and deformation. From this emerges not only a set of design trends corresponding to the dimensions of two particularly powerful types of micro surface shaping, but also a profound insight into the behavior of the water-lubricated piston-cylinder interface fluid film, and how that behavior can be manipulated by changing the component surfaces that constitute its borders. Furthermore, in collaboration with Danfoss High Pressure Pumps, a physical prototype of a 444 cc axial piston pump with surface shaping generated via the aforementioned algorithm has been constructed and tested, achieving a total pump efficiency roughly 3% higher than that achievable by the commercial unit that the geometry of the prototype is based on.
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Knox, William Bradley. "Learning from human-generated reward." 2012. http://hdl.handle.net/2152/19472.
Full textAbstract:
Robots and other computational agents are increasingly becoming part of our daily lives. They will need to be able to learn to perform new tasks, adapt to novel situations, and understand what is wanted by their human users, most of whom will not have programming skills. To achieve these ends, agents must learn from humans using methods of communication that are naturally accessible to everyone. This thesis presents and formalizes interactive shaping, one such teaching method, where agents learn from real-valued reward signals that are generated by a human trainer. In interactive shaping, a human trainer observes an agent behaving in a task environment and delivers feedback signals. These signals are mapped to numeric values, which are used by the agent to specify correct behavior. A solution to the problem of interactive shaping maps human reward to some objective such that maximizing that objective generally leads to the behavior that the trainer desires.
Interactive shaping addresses the aforementioned needs of real-world agents. This teaching method allows human users to quickly teach agents the specific behaviors that they desire. Further, humans can shape agents without needing programming skills or even detailed knowledge of how to perform the task themselves. In contrast, algorithms that learn autonomously from only a pre-programmed evaluative signal often learn slowly, which is unacceptable for some real-world tasks with real-world costs. These autonomous algorithms additionally have an inflexibly defined set of optimal behaviors, changeable only through additional programming. Through interactive shaping, human users can (1) specify and teach desired behavior and (2) share task knowledge when correct behavior is already indirectly specified by an objective function. Additionally, computational agents that can be taught interactively by humans provide a unique opportunity to study how humans teach in a highly controlled setting, in which the computer agent’s behavior is parametrized.
This thesis answers the following question. How and to what extent can agents harness the information contained in human-generated signals of reward to learn sequential decision-making tasks? The contributions of this thesis begin with an operational definition of the problem of interactive shaping. Next, I introduce the tamer framework, one solution to the problem of interactive shaping, and describe and analyze algorithmic implementations of the framework within multiple domains. This thesis also proposes and empirically examines algorithms for learning from both human reward and a pre-programmed reward function within an MDP, demonstrating two techniques that consistently outperform learning from either feedback signal alone. Subsequently, the thesis shifts its focus from the agent to the trainer, describing two psychological studies in which the trainer is manipulated by either changing their perceived role or by having the agent intentionally misbehave at specific times; we examine the effect of these manipulations on trainer behavior and the agent’s learned task performance. Lastly, I return to the problem of interactive shaping, for which we examine a space of mappings from human reward to objective functions, where mappings differ by how much the agent discounts reward it expects to receive in the future. Through this investigation, a deep relationship is identified between discounting, the level of positivity in human reward, and training success. Specific constraints of human reward are identified (i.e., the “positive circuits” problem), as are strategies for overcoming these constraints, pointing towards interactive shaping methods that are more effective than the already successful tamer framework.text
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"Exploring socio-technical relations : perceptions of Saskatoon Transit’s go-pass smartcard and electronic fare system." Thesis, 2012. http://hdl.handle.net/10388/ETD-2012-12-915.
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It is essential to consider what new technologies mean to the people who use them and the ways in which they are experienced and used. In the context of public transit services in Saskatoon, understanding what the recent changes from a manual to an electronic/automated system means to users and the broader community is critically important to the overall assessment of the service. Investigating users’ lived experiences and interpretations of technical artifacts is valuable to understanding socio-technical relations or the embodied interactions of humans and machines as “technologies-in-practice.”
Research into socio-technical relations has primarily focused on large scale technological systems and expert practices while less attention has been paid to “seemingly mundane” technologies or technical artifacts routinely used in everyday life. At the same time, this preoccupation has overshadowed or downplayed the importance of exploring users’ experiences and interpretations of technologies.
The goal of this research is to contribute to the sociological understanding of mundane technologies-in-practice and socio-technical relations more broadly. In order to gain insight into this relationship, this thesis focuses on bus riders’ (users) and the community’s perceptions of the Go-Pass smartcard and electronic fare system used by the public transit service in Saskatoon. The perspectives of Go-Pass users and community stakeholders (n=15) were investigated using qualitative semi-structured interviews to gain deeper understanding into the complex relationship between users and technologies.
Drawing from Science and Technology Studies (STS) and the sociology of technology literature, I propose that a sociomaterial theoretical perspective following a mutual shaping framework offers insight into socio-technical relations. Both critical and feminist technology studies literature has been helpful for developing an understanding of the wider social and political contexts of technical use which underscores this study. In particular, the conceptual insights of “socio-technical assemblages” (Suchman, 2007) and “intra-action” (Barad, 2003) have been helpful tools for exploring agency, subjectivity and power which is key to uncovering the intricacies of socio-technical relations and human-machine interaction. The four main themes emerging from this study were: 1) shifting human-machine roles and relationships; 2) the socio-technical construction of the bus rider; 3) configuring users’ and technologies; and 4) structural issues and social justice implications of technologies-in-practice.
The findings demonstrate that the use of this new system is mutually co-constructed by both social and technical factors whereby both the users and the technology inform perceptions and use. There was also the unexpected connection between users’ everyday situated uses, experiences and interpretations of the Go-Pass technologies to wider social-political contexts. There were a number of issues raised in relation to the implementation of the Go-Pass system which had negative effects or unintended social and technical consequences particularly for those most marginalized economically. At the same time, there were important benefits and positive effects on riders’ quality of life and use of the service. Finally, participants’ perspectives have contributed to understanding what the Go-Pass technologies mean to them, the ways in which they are used in practice and the ways in which the mixing of people and seemingly mundane technologies shape relations in everyday settings.
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Skinner, James. "Input current shaping in inverters driving brushless DC machines." 1990. http://catalog.hathitrust.org/api/volumes/oclc/23661922.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1990.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 29).
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Белянцева, И. В., and I. V. Belyantseva. "Разработка принципов построения схем зубофрезерного станка с безгитарным приводом : магистерская диссертация." Master's thesis, 2017. http://hdl.handle.net/10995/48444.
Full textAbstract:
Relevance of this research is conditioned by necessity of increasingmetalworking machines efficiency in modern machinery building.
One of the main constructive elements of gear milling machines is mechanical gear train (speed gear train, feed gear train, dividing gear train, differential gear train). The adjustment of all these shaping moves is important objective.
Though mechanical gear trains do not provide high tooling precision.That’s why precision can be increased by developing ways of replacing mechanical gear trains by hydraulic and electronic analogs. These ways were poorly considered before.
Goal of the work: analyzing of existing principal gear milling machine schemes, analyzing of possible ways of shaping moves electronic adjustment, descrying of various frequent divisor structures. Calculation unevennessof impulses following for divisors, that work in different codes and improving schemes of machines with electric step motor and adjustable electric motor by way of increasing tooling precision.
Master’s dissertation consists of 6 chapters:
Chapter 1: Modern gear milling machines principal schemes.
This chapter describes function of gear trains, structure of cutting moves in gear milling and schemes of existing gear milling machines with mechanical and electronic gear trains.
Chapter 2: Analysis of ways and tools of electronic (“Non-gear-train”) adjustment of machine’s shaping moves.
This chapter describes ways of coordinating an adjustable electronic motor and electronic step motor, ways of coordinating two adjustable electronic motors.
Chapter 3: modern constructions of impulse frequency divisors. Schemes andfunctioning of divisors.
This chapter analyze various schemes of frequency divisors, ways of divisor selecting for gear milling machine, calculating the unevenness of impulses, transferring with divisors for various codes.
Chapter 4: Improvement of gear milling machines with electric step motor
Suggestion of improved kinematic schemes for electric step motor milling machines.
Chapter 5: Improvement in schemes of gear milling machines with adjustable electric motor.
Suggestion of improved kinematic schemes for adjustable electric motor milling machines.
Chapter 6: Work out of technical proposal for gear milling machine with adjustable electric motor.
Chapter contains selection of electric motor for chosen kinematic scheme with electronic gear train, kinematic and robustness calculation, comparison of mechanical and electronic gears’ precision.
Master’s dissertation consist of 128 pages, containing demonstrational materials, calculations and text description, and 17 graphic documents.Актуальность темы исследования обусловлена необходимостью повышения эффективности металлорежущих станков в современном машиностроении. Одними из основных конструктивных элементов зубофрезерного станка являются механические гитары (скоростей, подач, деления, дифференциала). Важной задачей является согласовать всеэти формообразующие движения. Но механические гитары не обеспечивают высокой точности обработки. Поэтому были разработаны способы повышения точности путем замены механических гитар гидравлическими и электронными. Ранее эти способы были рассмотрены поверхностно. Цель работы: проведение анализа существующих принципиальных схем зубофрезерных станков, анализ возможных способов электронного согласования формообразующих движений, рассмотрение различных конструкций делителей частоты, расчет неравномерности следования импульсов для делителей, работающих в различных кодах, и совершенствование схем станков с шаговым и регулируемым электроприводами для повышения точности обработки. Магистерская диссертация состоит из 6 глав: Глава 1: Принципиальные схемы современных зубофрезерных станков В главе рассматривается назначение гитар, структура рабочего движения при зубофрезеровании, а также существующие кинематические схемы зубофрезерных станков с механическими и электронными гитарами. Глава 2: Анализ способов и средств электронного («безгитарного») согласования формообразующих движений в станке В главе описываются способы согласования работы регулируемого и шагового приводов, и согласование работы двух регулируемых приводов. Глава 3: Современные конструкции делителей частоты импульсов, их устройство и работа В главе анализируются различные конструкции делителей частоты, также производится выбор делителя, применительно к зубофрезерному станку. Производится расчет неравномерности следования импульсов, передаваемых через делители для различных кодов. Глава 4: Совершенствование зубофрезерных станков с шаговым электроприводом Предлагаются усовершенствованные кинематические схемы станков с шаговыми электроприводами. Глава 5: Совершенствование схем зубофрезерных станков с регулируемыми электроприводами Предлагаются усовершенствованные кинематические схемы станков с регулируемыми электроприводами. Глава 6: Разработка технического предложения зубофрезерного станка с регулируемыми электроприводами В главе выбирается электродвигатель для выбранной кинематической схемы с электронной гитарой, производится кинематический и прочностной расчет и сравниваются по точности механическая и электронная гитары. Магистерская диссертация выполнена на 128 страницах, содержащих демонстрационные материалы, расчеты и описание, и включает 17 графических документов.
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(5930510), Ashkan Abbaszadeh Darbani. "EFFECTS OF SLIPPER SURFACE SHAPING AND SWASHPLATE VIBRATION ON SLIPPER-SWASHPLATE INTERFACE PERFORMANCE." Thesis, 2019.
Find full textAbstract:
This thesis investigates the effects of swashplate vibration and slipper surface geometry on the performance of the slipper-swashplate interface. The lubricating interfaces within a swashplate type axial piston machine are the most complicated part of the design process. These interfaces are supposed to provide support to the significant loads they experience during operation and to prevent continuous contact of the sliding surfaces. Therefore a proper slipper-swashplate interface design ensures full film lubrication during operation and provides sufficient load support while minimizing viscous and volumetric losses at the same time. The effects of two factors on the performance of the slipper-swashplate are examined during this work; swashplate vibration and slipper surface micro-geometry. An already existing model of the slipper-swashplate interface was used to carry out the results for this work however some modifications were made to the model to suit the needs of this research. Swashplate vibration is a phenomenon that has not been implemented in the model before, therefore its effects on the performance of the interface were analyzed. Thickness of the fluid film in the lubricating regime corresponds with its performance and is directly affected by the micro-geometry of the sliding interfaces. Therefore the effects of slipper surface micro-geometry is crucial to study in order to find the optimal slipper-swashplate interface design.