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Esrafilian, Omid. "Learning from the sky : design of autonomous radio-enabled unmanned aerial vehicles in mobile cellular networks." Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS307.
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L'utilisation de drones dans les réseaux sans fil a récemment suscité un vif intérêt. La première partie de cette thèse vise à étudier les travaux actuels sur les communications sans fil assistées par des drones et à développer de nouvelles méthodes pour le placement et la conception de la trajectoire d'un drone en tant que RAN volant dans les réseaux sans fil. Nous soulignons comment l'utilisation de cartes 3D des villes peut apporter des avantages substantiels pour l'autopositionnement fiable des radios volantes.Quel que soit l'emplacement ou la conception du chemin, tous les algorithmes fonctionnent sur la base d'un ensemble d'informations telles que la localisation GPS du nœud, la carte 3D de la ville, etc. permettant de prédire l'intensité des signaux radio. Si ces données peuvent être collectées par le réseau avant le vol réel du drone, une partie ou la totalité des informations peuvent également devoir être apprises par le drone. À cet égard, une partie de cette thèse est consacrée à la discussion sur la façon d'apprendre ces informations à partir des mesures prises par le drone. Dans l'hypothèse d'une connectivité cellulaire sûre, les drones deviennent prometteurs pour un large éventail d'applications telles que les transports, etc. Le principal défi dans ces domaines est la conception de trajectoires qui garantissent une connectivité cellulaire fiable tout au long du trajet tout en permettant l'accomplissement de la mission du drone. Ainsi, dans la deuxième partie de cette thèse, nous proposons une nouvelle approche pour la conception optimale de trajectoires entre un point initial et un point terminal en s'appuyant sur une carte de couvertureThe use of UAVs in wireless networks has recently attracted significant attention. The first part of this thesis aims to investigate current works of UAV-aided wireless communications and develop novel methods for both the placement and path design of a UAV as a flying RAN in wireless networks. We highlight how the use of city 3D maps can bring substantial benefits for the reliable self-placement of flying radios.Regardless of the placement or path design, all algorithms operate on the basis of an array of information such as node GPS location, the city 3D map, etc. allowing the prediction of radio signal strengths. While such data may be collected via the network before the actual UAV flight, part or all of the information may also have to be learned by the UAV. In this regard, a part of this thesis is devoted to discussing how to learn such information from the UAV-borne measurements.Assuming the availability of safe cellular connectivity, UAVs are becoming promising for a wide range of applications such as transportation, etc. The main challenge in these areas is the design of trajectories that guarantee reliable cellular connectivity all along the path while allowing the completion of the UAV mission. Hence, in the second part of this thesis, we propose a novel approach for optimal path design between an initial and terminal points by leveraging on a coverage map. Lastly, we discuss the experimental verification of the placement algorithm of a UAV relay in LTE networks
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Al-Chami, Oussama. "Contribution à l'intégration Robotique/Vision en manipulation automatisée : modélisation de la tache, placement d'une caméra mobile et localisation fine d'objet." Grenoble INPG, 1994. http://www.theses.fr/1994INPG0118.
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Pour qu'un robot puisse manipuler un objet connu (saisir, demonter, etc) il doit connaitre sa position/orientation. Par ailleurs, pour localiser un objet par la perception visuelle, il faut plusieurs images qui doivent remplir des conditions imposees par le processus de localisation mis en jeu. La position/orientation de la camera utilisee ainsique sa mise au point, font partie de ces conditions. Cette camera est embarquee sur un robot qui assure son deplacement. Dans cette these, nous contribuons a l'integration robotique/vision en considerant les aspects suivants: 1 la modelisation des taches et des environnements partiellement connus. Pour cela, nous presentons un systeme de simulation et de modelisation mixte: cao-robotique et donnees perceptives. 2 le developpement d'une methode de positionnement automatique d'une camera mobile en fonction d'une tache perceptive (localisation, controle d'execution visuelle, etc). 3 la localisation fine d'un objet de forme quelconque a l'aide des donnees de la perception visuelle. 4 l'integration de l'ensemble des methodes developpees et les outils adoptes dans le systeme act de cao-robotique
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Moutran, Serge Riad. "Feasible Workspace for Robotic Fiber Placement." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/32738.
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Online consolidation fiber placement is emerging as an automated manufacturing process for the fabrication of large composite material complex structures. While traditional composite manufacturing techniques limited the productsâ size, geometrical shapes and laminate patterns, robotic automation of the fiber placement process allows the manufacture of complex bodies with any desired surface pattern or towpregâ s direction. Therefore, a complete understanding of the robot kinematic capabilities should be made to accurately position the structureâ s substrate in the workcell and to compute the feasible product dimensions and sizes.
A Matlab algorithm is developed to verify the feasibility of straight-line trajectory paths and to locate all valid towpreg segments in the workspace, with no focus on optimization. The algorithm is applied preliminary to a three-link planar arm; and a 6-dof Merlin robot is subsequently considered to verify the towpreg layouts in the three-dimensional space. The workspace is represented by the longest feasible segments and plotted on parallel two-dimensional planes. The analysis is extended to locate valid square areas with predetermined dimensions. The fabrication of isotropic circular coupons is then tested with two different compaction heads. The results allow the formulation of a geometric correlation between the end-effector dimensional measures and the orientation of the end-effector with respect to the towpreg segments.Master of Science
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Saunders, Benjamin R. (Benjamin Robert). "Optimal trajectory design under uncertainty." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76902.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 121-123).
Reference trajectory design for atmospheric reentry vehicles can be accomplished through trajectory optimization using optimal control techniques. However, this method generally focuses on nominal vehicle performance and does not include robustness considerations during trajectory design. This thesis explores the use of linear covariance analysis to directly include trajectory robustness in the design process. The covariance matrix can be propagated along a trajectory to provide the expected errors about the nominal trajectory in the presence of uncertainties. During the optimization process, the covariance matrix is used as a performance metric to be minimized, directly penalizing expected errors so that the trajectory is shaped to reduce its sensitivity to uncertainties. This technique can penalize the open-loop covariance of the trajectory or the closed-loop covariance with the inclusion of a feedback guidance law. This covariance shaping technique is applied to reference trajectory design for a generic small reentry vehicle. A baseline trajectory is generated without any robustness considerations, along with an open-loop covariance shaped trajectory and a closed-loop covariance shaped trajectory, which uses a feedback guidance law based on a linear quadratic regulator scheme. Uncertainties in initial conditions, atmospheric density, aerodynamic coefficients, and unmodeled dynamics are applied to each trajectory and performance is analyzed using linear covariance analysis and Monte Carlo simulations. The results show that when the vehicle is flown closed-loop with feedback, shaping using the open-loop covariance produces a trajectory that is less robust than the baseline trajectory, while shaping using the closed-loop covariance generates a trajectory with reduced sensitivity to uncertainty for more robust performance.
by Benjamin R. Saunders.
S.M.
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Macdonald, Malcolm. "Analytical methodologies for solar trail trajectory design." Thesis, University of Glasgow, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425065.
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Fisher, Callen. "Trajectory Optimisation Inspired Design for Legged Robotics." Doctoral thesis, Faculty of Engineering and the Built Environment, 2021. http://hdl.handle.net/11427/33715.
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Control of legged robots is a non-trivial task, especially when looking at aperiodic (non-steadystate) manoeuvres such as rapid acceleration and deceleration. Observing nature, animals are seen to effortlessly perform these rapid transient manoeuvres, however, robust walking is still considered a complex task in the robotics literature. For robots to successfully explore the unknown world outside of the laboratory environment, these transient manoeuvres need to be thoroughly understood and mastered. As controlling and designing legged robots is an extremely complex task, this thesis argues that trajectory optimisation methods can be employed to make various aspects of design more tractable. First trajectory optimisation methods were employed to determine how legged robots should accelerate. In nature animals are seen to leap straight into the desired gait, however, in the robotics literature, robots often perform multiple discrete gait transitions, or accelerate extremely slowly. The results of the study revealed that the optimal method to accelerate was to launch straight into the desired gait (for both bipeds and quadrupeds), with a sliding mass template model emerging for all results. Another discrepancy between the literature and nature is that animals have active spines which have been shown to aid in rapid locomotion tasks. In the robotics literature a number of spines exists, however, which is the optimal morphology for transient manoeuvres? Using Monte Carlobased trajectory optimisation methods, the rigid, revolute and prismatic spine morphologies were compared, with results showing the prismatic spine was the optimal configuration for long-time-horizon tasks. Due to transient locomotion requiring accurate and complex whole-body models, resulting in computationally expensive optimisation problems, an “optimisation-inspired” approach (akin to “bioinspiration”) was taken to identify heuristics and trends for a monopod robot. Initially, optimal trajectories for a two link leg monopod were analysed. Interestingly, during the stance phase, the axial force of the leg behaved in a “bang-bang” like fashion with fine hip torque control. Furthermore the aerial phase showed correspondence to the popular Raibert style controller. This resulted in the development of a hybrid pneumatic-electric monopod robot as a test-bed. Trajectories were then optimised for the robot to determine if these heuristics held. From these results, a stance phase PD controller for the hip actuator was developed and simulated under disturbances to test robustness. The resulting controller and heuristic was successfully tested on the platform, performing a long-time-horizon motion, which included transient phases of acceleration and deceleration.
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Sankaranarayanan, S. "Topology optimization with simultaneous analysis and design." Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-05042006-164513/.
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Curzi, Giacomo. "Trajectory design of a multiple flyby mission to asteroids." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
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In designing the trajectory for a multiple flyby mission to asteroids the choice of the targets is the most challenging problem.
This dissertation faces this problem in the framework of the recently issued medium-size mission call (M5) from ESA: CASTAway.
Starting from the preliminary work done in [6], this thesis develops a methodology for sequencing the potential targets in a multiple flyby mission.
In order to reduce the computational time, the complete database of known small bodies is firstly pruned on the base of heuristic considerations.
Using the assumption of small manoeuvres, a chief orbit concept could be used. Thus, two heuristic thresholds are defined in order to exclude non-promising targets given a chief orbit.
The sequencing process takes chief orbit and promising targets as inputs and gives a set of candidate sequences.
The results of such a process are analysed in the CASTAway framework and the best feasible sequence studied in details.
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Piggott, Scott. "Solar sail trajectory design and control in unrestricted frames." Diss., Connect to online resource, 2005. http://wwwlib.umi.com/cr/colorado/fullcit?p1425788.
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Petropoulakis, L. "Design of digital trajectory tracking systems for robotic manipulators." Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384976.
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Mandy, Christophe Ph (Christophe Philippe). "Trajectory design and control for formation flying spaceborne interferometers." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/51633.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2009.Includes bibliographical references (p. 125-127).
Spaceborne interferometry promises to greatly expand our knowledge of astronomy and astrophysics, and open the doors to many new discoveries. The purpose of this study is to investigate optimal resource management techniques for separated space-craft interferometers to successfully synthesize images. Assuming optimal imaging configurations that satisfy astronomical requirements have been selected, a two-step approach is taken to satisfy these requirements: (1) develop a framework to man-age control effort among different satellites during observation and retargeting of the spacecraft formations, to thereby maximize the number of observations that can be taken with a given amount of consumables, and (2) determine computationally efficient control techniques to minimize control effort while meeting image synthesis metrics. First, issues relating to planning optimal trajectories that trade imaging metrics for spacecraft design metrics such as mission length and spacecraft mass are addressed. The determination of optimal spacecraft locations or trajectories for image acquisition is studied to satisfy astronomical constraints. These positioning requirements lead to the computation of trajectories for the retargeting of formation flying interferometers to capture images of a new astronomical target. Second, the trajectories planned under this approach are used in the formulation of a tracking control problem for spaceborne interferometric apertures.
(cont.) The assumptions made in the control problem are used as a basis for the development of different control techniques that trade image quality for fuel expenditure, and evaluated according to scenarios involving different properties relevant to synthetic imaging. The result from these two steps are then applied to the SPHERES testbed, a six-degree-of-freedom facility designed for the incremental maturation of formation flight technologies in a risk-tolerant microgravity environment. Results from simulations and experiments on board the space station are presented and compared to their theoretical outcomes.
by Christophe Ph. Mandy.
S.M.
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Berahzer, Damien M. "Scroll Placement and Handedness." Thesis, School of Information and Library Science, 2005. http://hdl.handle.net/1901/165.
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This study explored how individuals categorized on handedness (being left or right hand dominant) reacted to having the vertical scroll bar of a web browser relocated to the left side of the screen. The relocation of the vertical scroll bar served as an alternative to the relocation of the prominent left aligned main navigation menu for most websites. Fifteen participants were recruited for the study. Each participant interacted with two versions of a web site in a modified browser to complete a set of ten short tasks. Participants completed tasks by interacting with a traditional and non-traditional vertical browser alignment. Left and right-handed participants were determined to be strikingly different in operation. Vertical scroll relocation produced some interesting results and responses.
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Guo, Pei-Ning. "Floorplan and placement approaches for VLSI physical design /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9914071.
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Grant, Michael James. "Rapid simultaneous hypersonic aerodynamic and trajectory optimization for conceptual design." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43685.
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Traditionally, the design of complex aerospace systems requires iteration among segregated disciplines such as aerodynamic modeling and trajectory optimization. Multidisciplinary design optimization algorithms have been developed to efficiently orchestrate the interaction among these disciplines during the design process. For example, vehicle capability is generally obtained through sequential iteration among vehicle shape, aerodynamic performance, and trajectory optimization routines in which aerodynamic performance is obtained from large pre-computed tables that are a function of angle of attack, sideslip, and flight conditions. This numerical approach segregates advancements in vehicle shape design from advancements in trajectory optimization. This investigation advances the state-of-the-art in conceptual hypersonic aerodynamic analysis and trajectory optimization by removing the source of iteration between aerodynamic and trajectory analyses and capitalizing on fundamental linkages across hypersonic solutions.
Analytic aerodynamic relations, like those derived in this investigation, are possible in any flow regime in which the flowfield can be accurately described analytically. These relations eliminate the large aerodynamic tables that contribute to the segregation of disciplinary advancements. Within the limits of Newtonian flow theory, many of the analytic expressions derived in this investigation provide exact solutions that eliminate the computational error of approximate methods widely used today while simultaneously improving computational performance. To address the mathematical limit of analytic solutions, additional relations are developed that fundamentally alter the manner in which Newtonian aerodynamics are calculated. The resulting aerodynamic expressions provide an analytic mapping of vehicle shape to trajectory performance. This analytic mapping collapses the traditional, segregated design environment into a single, unified, mathematical framework which enables fast, specialized trajectory optimization methods to be extended to also include vehicle shape.
A rapid trajectory optimization methodology suitable for this new, mathematically integrated design environment is also developed by relying on the continuation of solutions found via indirect methods. Examples demonstrate that families of optimal hypersonic trajectories can be quickly constructed for varying trajectory parameters, vehicle shapes, atmospheric properties, and gravity models to support design space exploration, trade studies, and vehicle requirements definition. These results validate the hypothesis that many hypersonic trajectory solutions are connected through fast indirect optimization methods. The extension of this trajectory optimization methodology to include vehicle shape through the development of analytic hypersonic aerodynamic relations enables the construction of a unified mathematical framework to perform rapid, simultaneous hypersonic aerodynamic and trajectory optimization. Performance comparisons relative to state-of-the-art methodologies illustrate the computational advantages of this new, unified design environment.
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Chong, Gregory Chow Ye. "Trajectory-scheduling control systems and their multi-objective design automation." Thesis, University of Glasgow, 2006. http://theses.gla.ac.uk/3728/.
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This thesis encompasses the analysis of TSN systems and their multi-objective design methods. TSN nodes are networked through interpolation and activation, similar to a gain-scheduling or local model/controller network. However, to achieve accuracy and ease of commissioning without requiring a large number of nodes, an algorithm has been developed first to identify optimum transition nodes within the entire operating envelope. Then the TSN approaches a nonlinear plant globally, not just locally, without requiring linearization. If desired or necessary, global optimisation provides an enhancement in the design process for TSNs. Since optimising only one aspect (a single objective) of performance while compromising others is undesirable, multi-objective designs have been developed concurrently to deliver or improve multiple aspects of performance. Following the development of a TSN, it is applied to nonlinear system modelling, and this TSN is termed a Trajectory-Scheduling Model (TSM). A TSM possesses the same properties and design features as the TSN generic framework. A nonlinear system, a coupled liquid-tank, is used to examine this modelling technique. Results verify the feasibility and effectiveness of the methods developed and validates the TSM. Further, the TSN technique is applied to nonlinear controller design, by way of a Trajectory-Scheduling Controller (TSC) network. It is illustrated through the design of a networked, easy-to-understand and easy-to-use PID control system for the coupled liquid-tank. Results show that the methods developed offer a high-performance linear control system with nonlinear capabilities to handle practical systems operating in a broad range and to cope with conflict between setpoint following at transient and disturbance rejection at steady state. This method is then applied to the PID network design problems for two nonlinear chemical processes.
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Basset, Gareth. "Virtual Motion Camouflage Based Nonlinear Constrained Optimal Trajectory Design Method." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5116.
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Nonlinear constrained optimal trajectory control is an important and fundamental area of research that continues to advance in numerous fields. Many attempts have been made to present new methods that can solve for optimal trajectories more efficiently or to improve the overall performance of existing techniques. This research presents a recently developed bio-inspired method called the Virtual Motion Camouflage (VMC) method that offers a means of quickly finding, within a defined but varying search space, the optimal trajectory that is equal or close to the optimal solution. The research starts with the polynomial-based VMC method, which works within a search space that is defined by a selected and fixed polynomial type virtual prey motion. Next will be presented a means of improving the solution's optimality by using a sequential based form of VMC, where the search space is adjusted by adjusting the polynomial prey trajectory after a solution is obtained. After the search space is adjusted, an optimization is performed in the new search space to find a solution closer to the global space optimal solution, and further adjustments are made as desired. Finally, a B-spline augmented VMC method is presented, in which a B-spline curve represents the prey motion and will allow the search space to be optimized together with the solution trajectory. It is shown that (1) the polynomial based VMC method will significantly reduce the overall problem dimension, which in practice will significantly reduce the computational cost associated with solving nonlinear constrained optimal trajectory problems; (2) the sequential VMC method will improve the solution optimality by sequentially refining certain parameters, such as the prey motion; and (3) the B-spline augmented VMC method will improve the solution optimality without sacrificing the CPU time much as compared with the polynomial based approach. Several simulation scenarios, including the Breakwell problem, the phantom track problem, the minimum-time mobile robot obstacle avoidance problem, and the Snell's river problem are simulated to demonstrate the capabilities of the various forms of the VMC algorithm. The capabilities of the B-spline augmented VMC method are also shown in a hardware demonstration using a mobile robot obstacle avoidance testbed.ID: 031001346; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: .; Title from PDF title page (viewed April 18, 2013).; Thesis (Ph.D.)--University of Central Florida, 2012.; Includes bibliographical references (p. 110-116).
Ph.D.
Doctorate
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering
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Allaoui, Chafik. "Evolutionary design of digital trajectory-tracking controllers for robotic manipulators." Thesis, University of Salford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299204.
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Bouadi, Hakim. "Contribution to flight control law design and aircraft trajectory tracking." Thesis, Toulouse, INSA, 2013. http://www.theses.fr/2013ISAT0001/document.
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Compte tenu de la forte croissance du trafic aérien aussi bien dans les pays émergents que dans les pays développés soutenue durant ces dernières décennies, la satisfaction des exigences relatives à la sécurité et à l’environnement nécessite le développement de nouveaux systèmes de guidage. L’objectif principal de cette thèse est de contribuer à la synthèse d’une nouvelle génération de lois de guidage pour les avions de transport présentant de meilleures performances en terme de suivi de trajectoire. Il s’agit en particulier d’évaluer la faisabilité et les performances d’un système de guidage utilisant un référentiel spatial. Avant de présenter les principales approches utilisées pour le développement de lois de commande pour les systèmes de pilotage et de guidage automatiques et la génération de directives de guidage par le système de gestion du vol, la dynamique du vol d’un avion de transport est modélisée en prenant en compte d’une manière explicite les composantes du vent. Ensuite, l’intérêt de l’application de la commande adaptative dans le domaine de la conduite automatique du vol est discuté et une loi de commande adaptative pour le suivi de pente est proposée. Les principales techniques de commande non linéaires reconnues d’intérêt pour le suivi de trajectoire sont alors analysées. Finalement, une loi de commande référencée dans l’espace pour le guidage vertical d’un avion de transport est développée et est comparée avec l’approche temporelle classique. L’objectif est de réduire les erreurs de poursuite et mieux répondre aux contraintes de temps de passage en certains points de l’espace ainsi qu’à une possible contrainte de temps d’arrivéeSafety and environmental considerations in air transportation urge today for the development of new guidance systems with improved accuracy for spatial and temporal trajectory tracking.The main objectives of this thesis dissertation is to contribute to the synthesis of a new generation of nonlinear guidance control laws for transportation aircraft presenting enhanced trajectory tracking performances and to explore the feasibility and performances of a flight guidance system developed within a space-indexed reference with the aim of reducing tracking errors and ensuring the satisfaction of overfly time constraints as well as final arrival time constraint. Before presenting the main approaches for the design of control laws for autopilots and auto-guidance systems devoted to transport aircraft and the way current Flight Management Systems generates guidance directives, flight dynamics of transportation aircraft, including explicitly the wind components, are presented. Then, the interest for adaptive flight control is discussed and a self contained adaptive flight path tracking control for various flight conditions taking into account automatically the possible aerodynamic and thrust parametric changes is proposed. Then, the main recognized nonlinear control approaches suitable for trajectory tracking are analyzed. Finally an original vertical space-indexed guidance control law devoted to aircraft trajectory tracking is developed and compared with the classical time-indexed approach
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Rodrigues, M. R. D. "A tree-based algorithm for component placement." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376139.
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Burby, Martin Laurence. "Design and evaluation of variable fuel-placement airblast atomizers." Thesis, University of Manchester, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.548665.
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Whittle, Jessica Kaye. "Strategic placement of viscous dampers for seismic structural design." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:58ea0592-a6de-438d-bc8c-5cc3cf1cf9ea.
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Seismic design with viscous devices is an effective means of dissipating seismic energy and protecting the main structural system from permanent damage. Despite numerous damper placement methods available, there lacks consensus on the best method, thus leaving design engineers without recommended placement strategies. The purpose of this research is to investigate strategic placement of viscous dampers for seismic design and to offer design recommendations for placing dampers, vertically and horizontally. Five damper placement techniques were selected for investigation, including standard methods, Uniform and Stiffness Proportional damping, and advanced methods, the Simplified Sequential Search Algorithm (SSSA method), the Optimal Damper Placement for Minimum Transfer Functions (Takewaki method), and the Fully-stressed Analysis/Redesign method (Lavan A/R method). Effectiveness of the techniques for distributing linear fluid viscous dampers for two building examples was evaluated under a suite of twenty ground motions, two seismic hazard levels, and in terms of peak interstorey drifts, absolute accelerations, and residual drifts using nonlinear time history analysis. The advanced methods showed comparable performance based on performance indicators. Therefore, usability is recommended as the selection criteria. The Lavan A/R method was found to be the most effective and usable method. It is recommended that multiple design ground motions be used for the SSSA Mode and Lavan A/R methods as well as caution against removal of upper storey damping, which prompts susceptibility to larger roof drifts due to higher-mode effects. Various brace-damper arrangements were explored to determine strategic horizontal damper placement. It was found that brace-damper arrangements with diagonals and multiple brace- damper sets per floor pose effective means of distributing the axial damper force and protecting the lower-storey columns from overstressing. Behavioural testing of two nonlinear viscous devices was performed, and results were used to determine analytical models for the nonlinear fluid viscous and fluid spring devices based on fitted parameters. It was found that the stress-relaxation models better captured the nonlinearity of the devices than standard models but yielded only marginally decreased energy dissipation per cycle. Thus, it is recommended that standard models are adequate for analysis of damped structures with these nonlinear viscous devices.
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Avnaïm, Francis. "Placement et déplacement de formes rigides ou articulées." Besançon, 1989. http://www.theses.fr/1989BESA2018.
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Parkinson, Jonathan Roger. "Optimizing Product Variant Placement to Satisfy Market Demand." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/855.
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Many companies use product families in order to offer product variants that appeal to different market segments while minimizing costs. Because the market demand is generally not uniform for all possible product variants, during the design phase a decision must be made as to which variants will be offered and how many. This thesis presents a new approach to solving this problem. The product is defined in terms of performance parameters. The market demand is captured in a preference model and applied to these parameters in order to represent the total potential market. The number and placement of the product variants are optimized in order to maximize percentage of the potential market that they span. This method is applied to a family of mountain bikes and a family of flow-regulating disks used in industrial applications. These examples show that usage of this method can result in a significant increase in potential market and a significant reduction in production costs.
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Huda, Md Nazmul. "Design, analysis and trajectory tracking control of underactuated mobile capsule robots." Thesis, Bournemouth University, 2016. http://eprints.bournemouth.ac.uk/24994/.
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The research on capsule robots (capsubots) has received attraction in recent years because of their compactness, simple structure and their potential use in medical diagnosis (e.g. capsule endoscopy), treatment and surgical assistance. The medical diagnostic capability of a capsule endoscope - which moves with the aid of visceral peristalsis - in the GI (gastro-intestinal) tract can be improved by adding propulsion to it e.g. legged, magnetic or capsubot-type propulsion. Driven by the above needs this thesis presents the design, analysis, trajectory tracking control and implementation of underactuated mobile capsule robots. These capsule robots can be modified and used in in-vivo medical applications. Researches on the capsubottype underactuated system focus on the stabilization of the robot and tracking the actuated configuration. However trajectory tracking control of an unactuated configuration (i.e. the robotmotion)was not considered in the literature though it is the primary requirement of any mobile robot and also crucial for many applications such as in-vivo inspection. Trajectory tracking control for this class of underactuated mechanical systems is still an open issue. This thesis presents a strategy to solve this issue. This thesis presents three robots namely a one-dimensional (1D) capsule robot, a 2D capsule robot and a 2D hybrid capsule robot with incremental capability. Two new acceleration profiles (utroque and contrarium) for the inner mass (IM) - internal moving part of the capsule robot - are proposed, analysed and implemented for the motion generation of the capsule robots. This thesis proposes a two-stage control strategy for the motion control of an underactuated capsule robot. A segment-wise trajectory tracking algorithm is developed for the 1D capsule robot. Theoretical analysis of the algorithm is presented and simulation is performed in the Matlab/Simulink environment based on the theoretical analysis. The algorithm is implemented in the developed capsule robot, the experimentation is performed and the results are critically analyzed. A trajectory tracking control algorithm combining segment-wise and behaviour-based control is proposed for the 2D capsule robot. Detailed theoretical analysis is presented and the simulation is performed to investigate the robustness of the trajectory tracking algorithm to friction uncertainties. A 2D capsule robot prototype is developed and the experimentation is performed. A novel 2D hybrid robot with four modes of operation - legless motion mode, legged motion mode, hybrid motion mode and anchoring mode - is also designed which uses one set of actuators in all operating modes. The theoretical analysis, modelling and simulation is performed. This thesis demonstrates effective ways of propulsion for in-vivo applications. The outer-shape of the 1D and 2D capsule robots can be customized according to the requirement of the applications, as the propulsion mechanisms are completely internal. These robots are also hermetically sealable (enclosed) which is a safety feature for the in-vivo robots. This thesis addresses the trajectory tracking control of the capsubot-type robot for the first time. During the experimentation the 1D robot prototype tracks the desired position trajectory with some error (relative mean absolute error: 16%). The trajectory tracking performance for the 2D capsubot improves as the segment time decreases whereas tracking performance declines as the friction uncertainty increases. The theoretical analysis, simulation and experimental results validate the proposed acceleration profiles and trajectory tracking control algorithms. The designed hybrid robot combines the best aspects of the legless and legged motions. The hybrid robot is capable of stopping in a suspected region and remain stationary for a prolonged observation for the in-vivo applications while withstanding the visceral peristalsis.
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Colombo, Camilla. "Optimal trajectory design for interception and deflection of Near Earth Objects." Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/1819/.
Full textAbstract:
Many asteroids and comets orbit the inner solar system; among them Near Earth Objects (NEOs) are those celestial bodies for which the orbit lies close, and sometimes crosses, the Earth’s orbit. Over the last decades the impact hazard they pose to the Earth has generated heated discussions on the required measures to react to such a scenario. The aim of the research presented in this dissertation is to develop methodologies for the trajectory design of interception and deflection missions to Near Earth Objects. The displacement, following a deflection manoeuvre, of the asteroid at the minimum orbit intersection distance with the Earth is expressed by means of a simple and general formulation, which exploits the relative motion equations and Gauss’ equations. The variation of the orbital elements achieved by any impulsive or low-thrust action on the threatening body is derived through a semi-analytical approach, whose accuracy is extensively shown. This formulation allows the analysis of the optimal direction of the deflection manoeuvre to maximise the achievable deviation. The search for optimal opportunities for mitigation missions is done through a global optimisation approach. The transfer trajectory, modelled through preliminary design techniques, is integrated with the deflection model. In this way, the mission planning can be performed by optimising different contrasting criteria, such as the mass at launch, the warning time, and the total deflection. A set of Pareto fronts is computed for different deflection strategies and considering various asteroid mitigation scenarios. Each Pareto set represents a number of mission opportunities, over a wide domain of launch windows and design parameters. A first set of results focuses on impulsive deflection missions, to a selected group of potentially hazardous asteroids; the analysis shows that the ideal optimal direction of the deflection manoeuvre cannot always be achieved when the transfer trajectory is integrated with the deflection phase. A second set of results includes solutions for the deviation of some selected NEOs by means of a solar collector strategy. The semi-analytical formulation derived allows the reduction of the computational time, hence the generation of a large number of solutions. Moreover, sets of Pareto fronts for asteroid mitigation are computed through the more feasible deflection schemes proposed in literature: kinetic impactor, nuclear interceptor, mass driver device, low-thrust attached propulsion, solar collector, and gravity tug. A dominance criterion is used to perform a comparative assessment of these mitigation strategies, while also considering the required technological development through a technology readiness factor. The global search of solutions through a multi-criteria optimisation approach represents the first stage of the mission planning, in which preliminary design techniques are used for the trajectory model. At a second stage, a selected number of trajectories can be optimised, using a refined model of the dynamics. For this purpose, the use of Differential Dynamic Programming (DDP) is investigated for the solution of the optimal control problem associated to the design of low-thrust trajectories. The stage-wise approach of DDP is exploited to integrate an adaptive step discretisation scheme within the optimisation process. The discretisation mesh is adjusted at each iteration, to assure high accuracy of the solution trajectory and hence fully exploit the dynamics of the problem within the optimisation process. The feedback nature of the control law is preserved, through a particular interpolation technique that improves the robustness against some approximation errors. The modified DDP-method is presented and applied to the design of transfer trajectories to the fly-by or rendezvous of NEOs, including the escape phase at the Earth. The DDP approach allows the optimisation of the trajectory as a whole, without recurring to the patched conic approach. The results show how the proposed method is capable of fully exploiting the multi-body dynamics of the problem; in fact, in one of the study cases, a fly-by of the Earth is scheduled, which was not included in the first guess solution.
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Abidin, Zainal. "Design of digital high-accuracy trajectory tracking systems for multivariable plants." Thesis, University of Salford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304589.
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Huntington, Geoffrey Todd 1979. "Trajectory design and analysis of a Mars-orbit rendezvous flight experiment." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/82798.
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McGregor, Andrew E. "A combined design and trajectory optimisation algorithm for an orbiter vehicle." Thesis, Cranfield University, 1995. http://dspace.lib.cranfield.ac.uk/handle/1826/10426.
Full textAbstract:
This thesis describes the
development of a computer program to optimise the design of
a rocket
powered orbiter vehicle, by combining a design synthesis with consideration
of both the ascent and
re-entry trajectories. This work is a extension of an existing
trajectory optimisation program.
Firstly the background to the problem is examined and a summary of previous work is
presented. The objectives of this research program are examined and there follows a
discussion of the mission
requirements for such a vehicle and a description of the
baseline
design.
The
development of this problem as a integrated optimal control problem is discussed
and is followed
by a description of the mathematical models which are used to evaluate
the vehicle. These include the geometry and packing model, the estimation of the
orbiter's mass
properties, the evaluation of the aerodynamics and the simulation of the
trajectories. The mathematical details of these models are presented in detail i the
appendices. The architecture and philosophy behind the writing of the program are
then discussed. A user's
guide is also presented as an appendix.
Results are
given for the solutions to a variety of orbiter design problems. These
problems include a variety of separation conditions for air-launched vehicles, various
re-entry cross-range conditions and a number of differing objective functions. A
investigation into the optimality of the solutions and their sensitivity to changes in the
optimisable parameters is also considered. The difficulty in obtaining optimal solutions
is discussed in full.
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Dedman, Phoebe Elizabeth. "Design of a Multi-objective Landing Trajectory Using Artificial Neural Networks." Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10837984.
Full textAbstract:
During approach and landing, the HL-20 follows a typical reusable launch vehicle (RLV) autoland trajectory: deep descent, followed by a parabolic flare, and final descent. The trajectory shape is determined by six independent parameters. An artificial neural network (ANN) is designed to generate the trajectory parameters for the HL-20 based on desired objectives using MATLAB®’s Neural Network Toolbox. This research examines three mission objectives: specifying flight time, specifying the final downrange position error, and specifying the average error between the desired angle of attack and actual angle of attack. The ANN successfully produces parameters that meet mission objectives and, in some cases, improve upon nominal errors. It is also demonstrated that the ANN structure and ANN training vectors have a profound impact on the success of the neural network.
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Ionescu, Stefan, and Kaj Jonsson. "Design Trade-offs in Optimisation Based Trajectory Planning for Autonomous Racing." Thesis, KTH, Mekatronik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254448.
Full textAbstract:
The autonomous vehicle industry is fast developing with many companies vying to release the first fully autonomous passenger vehicle. However, the advancement of the field also drives forward related areas such as autonomous racing. This paper aims to investigate how to optimally control an autonomous race car such that its progression across a previously unknown race track is maximised. This paper is inspired by the Formula Student race. The paper investigates using a Model Predictive Controller, MPC, to convert current vehicle position to a set of control inputs through the use of a vehicle model. Two different models have been investigated, the first focusing purely on the kinematics of the system, whilst the second encodes tyre forces for a dynamic approach. Further, the planning horizon of the MPC has been investigated to see how changes to it affect the performance of the controller and thus obtain insight into the trade-off between model complexity and planning horizon. Finally the limitations of both models was investigated. A modular real time implementation has been developed with the help of The CT Toolbox, a fast, C++ based, MPC implementation control toolbox. Small track segments and a full track have been used to evaluate the performance between the two models. Results showed that the computational difference from a more complex model is not a major limiting factor for the update rate of the MPC. However, the performance of the two models was significantly different with the dynamic based MPC far outperforming the kinematic. Constraining lateral accelerations of the car is critical when designing the controller as failure to do so will allow the controller to plan unfeasible paths. The dynamic model, through encoding the tyre forces, accomplishes this successfully completing the lap. However, the kinematic model, which assumes zero slip, fails as the speed gets high with sharp corners. It was also found that too short planning horizons do not allow sufficient information to flow to the controller causing poor trajectories. As one increases the planning horizon, diminishing returns appear as computational complexity increases with little improvements to the trajectory from the extra information. Finally it was found that sharp corners especially when chained together caused the most performance issues, however given an appropriate planning horizon, the dynamic model handles them well proposing a path similar to that of professional drivers. The paper outlines related works in the autonomous racing field, and gives an overview of the theory behind MPC. The focus then shifts onto how the system was setup, including the necessary theory, with an indepth look at the system architecture.Utvecklingen inom autonoma fordon är idag ett område som snabbt går framåt. Företag kämpar med att vara först ut på marknaden med full autonom styrning för fordon. Genom denna utveckling utforskas även närliggande områden, såsom racing. Arbetet kommer att fokusera på hur en autonom bil kan maximera hastigheten på en bana. Närmare bestämt optimal reglering för en autonom racing-bil. Arbetet har inspirerats av tävlingen Formula Student race, som är en tävling mellan universitet världen över. En modellbaserad kontrollstrategi implementeras, Model Predictive Control (MPC), som genom att modellera bilens dynamik tar beslut om bilens agerande. I arbetet så har två bilmodeller implementerats och jämförts. En kinematisk modell, där bilens agerande kan beskrivas med geometriska samband. Samt en dynamisk modell, som även tar hänsyn till de dynamiska sambanden som ges av bilens däck. Vidare så har olika tidshorisonter för kontrollern analyserats. Då både modellkomplexitet och tidshorisont ger ett negativt anspråk på beräkningstid, undersöks den avvägning som uppstår mellan varierande komplexitet hos modell vägt mot längd på tidshorisont. Slutligen så har det undersökts vilka begränsningar som är förknippade med modellerna. Implementering har gjorts med CT Toolbox, ett tidseffektivt C++ baserad ramverk för MPC styrning. Implementationen har sedan utvärderats genom att undersöka prestationen för modellerna på olika bansegment. Resultatet visade att skillnaden i beräkningstid för de två modellerna ej var en stor faktor för uppdateringsfrekvensen. Prestationen för de två modellerna visade sig skilja signifikant. I och med möjligheten att begränsa accelerationen i sidled för den dynamiska modellen kunde bilen justera hastigheten i kurvor, till skillnad ifrån den kinematiska modeller, där antagande om perfekt grepp gjorts. Undersökningen visade även att vid för kort tidshorisont, får kontrollern ej tillräckligt med nödvändig information, vilket resulterar i bristande planering. Vid ökning av tidshorisont, ökar beräkningstiden. Det påverkar prestandan positivt, men bara till en viss nivå, då för mycket information ej är tillämpbar av kontrollern. Detta arbete använder sig av tidigare gjord forskning inom autonoma racing-fordon, och ger en övergripande teori inom styrning med hjälp av MPC. Arbetet skiftar sedan till att implementera ett autonomt system vad gäller planering och styrning. Slutligen presenteras resultaten och en medföljande diskussion med förslag på hur detta kan förbättras vid framtida implementation.
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Okura, Yuki. "Trajectory Design Based on Robust Optimal Control and Path Following Control." Kyoto University, 2019. http://hdl.handle.net/2433/242499.
Full textAbstract:
付記する学位プログラム名: デザイン学大学院連携プログラムKyoto University (京都大学)
0048
新制・課程博士
博士(工学)
甲第21761号
工博第4578号
新制||工||1713(附属図書館)
京都大学大学院工学研究科航空宇宙工学専攻
(主査)教授 藤本 健治, 教授 泉田 啓, 教授 太田 快人
学位規則第4条第1項該当
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Stefanidis, Peter. "Pole-placement design of multivariable control systems using algebraic methods /." Title page, abstract and contents only, 1989. http://web4.library.adelaide.edu.au/theses/09ENS/09enss816.pdf.
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Almohanadi, A. H. "Application of analytical placement techniques for floorplanning in VLSI design." Thesis, University of Kent, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233396.
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Collins, Robert James. "Design of a Helicopter Slung Vehicle for Actuated Payload Placement." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/31882.
Full textAbstract:
Helicopters have been used in applications where they need to carry a slung load for years. More recently, unmanned (UAV) helicopters are being used to deliver supplies to military units on the ground in theaters of war. This thesis presents a helicopter slung vehicle used to carry the payload and furthermore, provide a means of actuation for the payload. This provides more control authority to the system and may ultimately allow a helicopter to fly higher with a longer tether.
The vehicle designed in this thesis was designed for use with 100kg class helicopters, such as the Yamaha RMAX operated by the Virginia Tech Unmanned Systems Lab. Each system on the vehicle was custom designed â including the propulsion system, wall detection / localization system, and controller. Three shrouded propellers provided thruster actuation. A scanning laser range finder and inertial measurement unit (IMU) were used to provide localization. A first attempt at a linear full state feedback controller with a complementary filter was used to control the vehicle.
All of the systems were tested individually for functionality. The shrouded propellers met their design goals and were capable of producing .7lbf of thrust each. The wall detection system was able to detect walls and windows reliably and with repeatability. Results from the controller however were less than ideal, as it was only able to control yaw in an oscillatory motion, most likely due to model deficiencies. A reaction wheel was used to control yaw of the vehicle with more success.Master of Science
35
Amarchinta, Sumanth. "High performance subthreshold standard cell design and cell placement optimization /." Online version of thesis, 2009. http://hdl.handle.net/1850/10740.
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Fogaça, Mateus Paiva. "A new quadratic formulation for incremental timing-driven placement." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/164067.
Full textAbstract:
O tempo de propagação dos sinais nas interconexões é um fator dominante para atingir a frequência de operação desejada em circuitos nanoCMOS. Durante a síntese física, o posicionamento visa espalhar as células na área disponível enquanto otimiza uma função custo obedecendo aos requisitos do projeto. Portanto, o posicionamento é uma etapa chave na determinação do comprimento total dos fios e, consequentemente, na obtenção da frequência de operação desejada. Técnicas de posicionamento incremental visam melhorar a qualidade de uma dada solução. Neste trabalho, são propostas duas abordagens para o posicionamento incremental guiado à tempos de propagação através de suavização de caminhos e balanceamento de redes. Ao contrário dos trabalhos existentes na literatura, a formulação proposta inclui um modelo de atraso na função quadrática. Além disso, o posicionamento quadrático é aplicado incrementalmente através de uma operação, chamada de neutralização, que ajuda a manter as qualidades da solução inicial. Em ambas as técnicas, o comprimento quadrático de fios é ponderado pelo drive strength das células e a criticalidade dos pinos. Os resultados obtidos superam o estado-da-arte em média 9,4% e 7,6% com relação ao WNS e TNS, respectivamente.The interconnection delay is a dominant factor for achieving timing closure in nanoCMOS circuits. During physical synthesis, placement aims to spread cells in the available area while optimizing an objective function w.r.t. the design constraints. Therefore, it is a key step to determine the total wirelength and hence to achieve timing closure. Incremental placement techniques aim to improve the quality of a given solution. Two quadratic approaches for incremental timing driven placement to mitigate late violations through path smoothing and net load balancing are proposed in this work. Unlike previous works, the proposed formulations include a delay model into the quadratic function. Quadratic placement is applied incrementally through an operation called neutralization which helps to keep the qualities of the initial placement solution. In both techniques, the quadratic wirelength is pondered by cell’s drive strengths and pin criticalities. The final results outperform the state-of-art by 9.4% and 7.6% on average for WNS and TNS, respectively.
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Bini, Cosimo. "A pick-and-place robot for coffee capsules: virtualization and trajectory design." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Find full textAbstract:
Even if Virtual Commissioning is not widely spread among industries yet, it offers plenty of advantages for the manufacturing of productive plants, that consist of reduced commissioning time, optimization of the code, better synergy between mechanical and software design. However, due to the cost of the requested investments, only big firms employ it in their production processes. This work aims at providing an example of how Virtual Commissioning can be applied to an automatic machine and how it can be used to improve the kinematic behaviour of two degrees of freedom manipulator, that moves coffee capsules into carton boxes. In particular, the simulations deal with the modifications of the parameters of the current trajectory and the test of a different kind of path for the robot, paying attention to collisions with the other parts of the machine.
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Anderson, Rodney L. "Low thrust trajectory design for resonant flybys and captures using invariant manifolds." Diss., Connect to online resource, 2005. http://wwwlib.umi.com/cr/colorado/fullcit?p3190349.
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Millard, Matthew. "Mechanics and Control of Human Balance." Thesis, 2011. http://hdl.handle.net/10012/5842.
Full textAbstract:
A predictive, forward-dynamic model and computer simulation of human gait has important medical and research applications. Most human simulation work has focused on inverse dynamics studies to quantify bone on bone forces and muscle loads. Inverse dynamics is not predictive - it works backwards from experimentally measured motions in an effort to find the forces that caused the motion. In contrast, forward dynamics determines how a mechanism will move without the need for experimentation. Most of the forward dynamic gait simulations reported consider only one step, foot contact is not modeled, and balance controllers are not used. This thesis addresses a few of the shortcomings of current human gait simulations by contributing an experimentally validated foot contact model, a model-based stance controller, and an experimentally validated model of the relationship between foot placement location and balance.
The goal of a predictive human gait simulation is to determine how a human would walk under a condition of interest, such as walking across a slippery floor, using a new lower limb prosthesis, or with reduced leg strength. To achieve this goal, often many different gaits are simulated and the one that is the most human-like is chosen as the prediction for how a person would move. Thus it is necessary to quantify how `human-like' a candidate gait is. Human walking is very efficient, and so, the metabolic efficiency of the candidate gait is most often used to measure the performance of a candidate gait. Muscles consume metabolic energy as a function of the tension they develop and the rate at which they are contracting. Muscle tension is developed, and contractions are made in an effort generate torques about joints in order to make them move. To predict human gait, it is necessary for the simulation to be able to walk in such a way that the simulated leg joints use similar joint torques and kinematics as a human leg does, all while balancing the body. The joint torques that the legs must develop to propel the body forward, and balance it, are heavily influenced by the ground reaction forces developed between the simulated foot and the ground. A predictive gait simulation must be able to control the model so that it can walk, and remain balanced while generating ground reaction force profiles that are similar to experimentally observed human ground reaction force profiles.
Ground reaction forces are shaped by the way the foot interacts with the ground, making it very important to model the human foot accurately. Most continuous foot contact models present in the literature have been experimentally validated using pendulum impact methods that have since been shown to produce inaccurate results. The planar foot contact model developed as part of this research was validated in-vivo using conventional force plates and optical tracking markers. The experimental data was also highly useful for developing a computationally efficient foot model by identifying the dominant contact properties of a real foot (during walking), without the complexity of modelling the 26 bones, 33 joints, over 90 ligaments, and the network of muscles that are in a real foot.
Both ground reaction forces and the balance of the model are heavily influenced by the way the stance limb is controlled. Anthropomorphic multibody models typically have a fragile sense of balance, and ground reaction force profiles that do not look similar to experimentally measured human ground reaction force profiles. In contrast, the simple point-mass spring-loaded-inverted-pendulum (SLIP) can be made to walk or run in a balanced manner with center-of-mass (COM) kinematics and ground reaction force profiles that could be mistaken for the equivalent human data. A stance limb controller is proposed that uses a planar SLIP to compute a reference trajectory for a planar anthropomorphic multibody gait model. The torso of the anthropomorphic model is made to track the computed trajectory of the SLIP using a control system. The aim of this partitioned approach to gait simulation is to endow the anthropomorphic model with the human-like gait of the simpler SLIP model.
Although the SLIP model-based stance-controller allows an anthropomorphic gait model to walk in more human-like manner, it also inherits the short comings of the SLIP model. The SLIP can walk or run like a human, but only at a fixed velocity. It cannot initiate or terminate gait. Fall preventing movements, such as gait termination and compensatory stepping, are of particular relevance to kinesiologists and health care professionals. Kinesiologists have known for nearly a decade that humans restore their balance primarily by systematically altering their foot placement location. This thesis presents a human experimental validation of a planar foot placement algorithm that was originally designed to restore the balance of bipedal robots. A three-dimensional (3D) theoretical extension to the planar foot placement algorithm is also presented along with preliminary human experimental results. These models of foot placement can be used in the future to improve the capabilities of gait simulations by giving simple models human-like compensatory stepping abilities. The theoretical extension also provides some insight into how instability and balance performance can be quantified. The instability and balance performance measures have important applications for diagnosing and rehabilitating balance problems.
Despite all of the progress that has been made, there is still much work to be done. Work needs to be continued to find methods that allow the anthropomorphic model to emulate the SLIP model more faithfully. Experimental work needs to be completed to realize the potential diagnostic and rehabilitation applications of the foot placement models. With continued effort, a predictive, balanced, multi-step gait simulation can be developed that will give researchers the time-saving capability of computerized hypothesis testing, and medical professionals improved diagnostic and rehabilitation methods.
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Ke, Hao-Yuan, and 柯皓元. "Projectile Trajectory and Placement Estimation Based on Stereo Vision." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/4862hx.
Full textAbstract:
碩士國立勤益科技大學
電機工程系
105
Projectile trajectory estimation systems are often used in military defense such as missiles, rockets and other parabolic trajectory prediction. However, they usually use radar or sonar detection methods, which can only provide local and passive information. When a human takes a flying projectile, fast he looks attentively at the projectile to estimate the object flight path, and then takes the object. In this paper, we propose projectile trajectory estimation systems based on stereo vision. Two parallel network cameras simulate the human eyes. The stereo vision algorithm is used to capture the target from images. The target’s images are calculated with SAD (Sum of Absolute Difference) algorithm for image matching to calculate the target’s position and height in images. Kalman Filter (KF) and Unscented Kalman Filter (UKF) are used to estimate the trajectory and the landing position of the projectile, when it flies in the space. Experiments are carried out in different illumination background, different volume and weight of projectiles. Experiments of projectile trajectory estimation by KF and UKF correspond closely to the real trajectory. The projectile trajectory estimations by UKF correspond more closely to the real trajectory than those by KF.
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Brennan, Martin James. "Patched conic interplanetary trajectory design tool." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-12-4849.
Full textAbstract:
One of the most important aspects of preliminary interplanetary mission planning entails designing a trajectory that delivers a spacecraft to the required destinations and accomplishes all the objectives. The design tool described in this thesis allows an investigator to explore various interplanetary trajectories quickly and easily. The design tool employs the patched conic method to determine heliocentric and planetocentric trajectory information. An existing Lambert Targeting routine and other common algorithms are utilized in conjunction with the design tool’s specialized code to formulate an entire trajectory from Earth departure to arrival at the destination. The tool includes many options for the investigator to accurately configure the desired trajectory, including planetary gravity assists, deep space maneuvers, and various departure and arrival conditions. The trajectory design tool is coded in MATLAB, which provides access to three dimensional plotting options and user adaptability. The design tool also incorporates powerful MATLAB optimization functions that adjust trajectory characteristics to find a configuration that yields the minimum spacecraft propellant in the form of change in velocity.text
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藍翰煌. "Automatic placement and parametric design." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/38402100961122084315.
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YUE, CHIH-SEM, and 游志聖. "ON THE ROBUST POLE-PLACEMENT DESIGN." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/83061266914985771190.
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碩士國立海洋大學
航運技術研究所
85
Robust pole-placement design is very important for the linear time-invariant controllable system. Our objective, in this thesis,is to develop a parametric solution for the robust control problem via the approach of hypothetical loop-decoupling and theconcept of hypothetical output. By taking advantages ofparametrization, we may tune these effective free parameters embeddedtherein such that the Frobenius norm of closed-loop system matrix can be made minimized. This thesis shows that the explicit linear parametric form for thefeedback gain matrix representing the class of controllers and alsopoints out that the flexibility of pole arrangement for the controlloops subjecting to the same set of controllability indices can also affect robustness of performance. We believe that parametrization can be useful in simultaneous pole-placement and optimal-performancedesign. The excellence of parametrization proposed in the thesis is illustrated by several numerical examples and by simulating these examples with free responses, with and without perturbations.
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Wu, Tsung-Han, and 吳宗翰. "Design Hierarchy Aware Routability Driven Placement." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/61169789757435038813.
Full textAbstract:
碩士國立交通大學
資訊科學與工程研究所
101
Placement plays a key role in physical design automation. Not only determining routing wire length lower bound, but also defining circuit design target density. Moreover, placement has a great impact on power consumption、timing and routability. At the same time with the technology node evolution, routing becomes more and more complex which makes routability becomes more and more important. Therefore this study implements ASIC global placer and integrates global router to get congestion information. This global placer mainly composed by three steps: I. Initial wire-length optimization. II. Design hierarchy aware initial global placement. III. Routability driven global placement including uses global router to get congestion map and using the information to do cell bloating.
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Bian, Huimin. "Placement By Marriage." Thesis, 2008. http://hdl.handle.net/1807/11133.
Full textAbstract:
As the field programmable gate array (FPGA) industry grows device
capacity with Moore's law and expands its market to high performance
computing, scalability of its key CAD algorithms emerges as a new
priority to deliver a user experience competitive to parallel
processors. Among the many walls to overcome, placement stands out due
to its critical impact on both frontend synthesis and backend routing.
To construct a scalable placement flow, we present three innovations
in detailed placement: a legalizer that works well under low
whitespace; a wirelength optimizer based on bipartite matching; and a
cache-aware annealer. When applied to the hundred-thousand cell IBM benchmark
suite, our detailed placer can achieve 27% better wirelength and
8X faster runtime against FastDP, the fastest academic
detailed placer reported, and our full placement flow can achieve 101X faster runtime, with 5% wirelength overhead, against VPR,
the de facto standard in FPGA placements.
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Chen, Chia-Han, and 陳佳漢. "Trajectory Control Design for Multi-Axis Motion Platform." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/80493176545622252629.
Full textAbstract:
碩士國立雲林科技大學
電機工程系
102
A PC-Based 3-axis XYZ control system is developed in this thesis. The Real-Time Workshop (RTW) tool in Matlab/Simulink software is used to execute the motion control. The time domain system identification method is applied here to obtain the X-axis and Y-axis system model. The Ziegler-Nichols rule is used to design the PID controller parameters. We also develop a Visual Basic software interface to control the platform with ADLINK motion control card. The P-command and V-command mode control are designed to evaluate the system performances. Four contour trajectories, like square, triangle, star and circle, are conducted successfully. It is shown that our proposed method provide the better performances on average tracking error and standard deviation for different contour tracking.
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陳柏璁. "Design and Implementation of Pattern-Aware Trajectory Search." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/68924946750561833716.
Full textAbstract:
碩士國立交通大學
資訊科學與工程研究所
97
In recent years, GPS-equipped devices are widely used in daily life. People can record their trajectories and share them on the Internet. As such data increases dramatically, several issues on trajectories have arisen. However, exploring meaningful trajectories from a trajectory database is important. In the traditional trajectory search, users can query a range to derive all trajectories in a trajectory database passing the region, or query a trajectory to derive trajectories in a trajectories database with higher similar- ities. In this paper, we intent to rank trajectories in a trajectory database and search top-k meaningful trajectories from the database with a given query range. We introduce a framework of pattern-aware trajectory search. In this framework, we propose a PageRank-like approach to discover implicit patterns from a trajectory database, and a pruning approach to improve the eciency for searching pattern-aware trajectories from a large database. We collect shared trajectories in Taiwan from several travel websites to evaluate the performance of our proposed approaches. Experimental results show effectiveness and eciency of our proposed approaches.
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Ren, Haoxing. "Incremental placement for modern VLSI design closure." Thesis, 2006. http://hdl.handle.net/2152/2626.
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Liu, Shih-Ying, and 劉時穎. "Algorithms on Placement Migration for Design Closure." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/eb88c8.
Full textAbstract:
博士國立交通大學
電子工程學系 電子研究所
102
To achieve design closure, design constraints including timing, power or routability are becoming more challenging as design complexity increases. Due to increase in design complexity, placement along is insufficient to simultaneously optimize multiple objectives. Thus, a general approach is to reserve additional white space to make room for gate sizing, buffer insertion and reduce routing overflow. However, reserving white space is a only a general approach and difficult to address specific objective. In addition, reserving white space increases die area can only be use conservatively. Thus, deploying optimizations at post-placement stage is a practical approach to optimize specific objective while maintaining the integrity of the original placement. Post-placement optimization techniques can be referred as placement migration, which is the movement of cells based on an existing placement solution to address a specific objective such as timing, routability or heat distribution. The key criterion of placement migration is to preserve the integrity of the original placement while optimizing the target objective. The integrity of the original placement can be measured through routing overflow, timing of critical paths, number of violation paths, etc. However, measuring these criteria is time consuming. A more efficient method to maintain the integrity of the original placement is to minimize displacement of cells. Total displacement and maximum displacement of cells can be controlled during placement migration. In this dissertation, we present three different approaches to achieve placement migration, each approach is targeted on specific objective with different method to move cells but all share common criterion, which minimize perturbation of cells. Integrity of original placement is kept by minimizing total displacement of cells. The first approach discusses flip-flop merging and re-allocation for multi-bit flip-flops. The second approach discusses on heat distribution for maximum temperature reduction based on network flow approach. The third approach presents an incremental placement engine based on Gaussian smoothing which is designed to improve relative order of cells at post-placement stage.
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Hu, Chun-Jui, and 胡峻睿. "Integrating Synthesis and Placement for Datapath Design." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/96145972212134570589.
Full textAbstract:
碩士國立清華大學
資訊工程學系
88
As the growth of design complexity and usage of datapath, the design flow for datapath has become important part of a whole design flow. This paper presents an integrated and iterative design flow to minimize the total wire length of a datapath. We divide the problem into three phases: synthesis, floorplan and placement. In order to generate regular layout, we present mixed synthesis option method for preserving regularity of design. In floorplan and placement phases, we analyze the connections of each datapath module to get proper placement option. For datapath and control logic mixed design, we also present an integrated design flow from RTL code to layout.