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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Vision-Based Motion for a Humanoid Robot

Alkhulayfi, Khalid Abdullah 13 July 2016 (has links)
The overall objective of this thesis is to build an integrated, inexpensive, human-sized humanoid robot from scratch that looks and behaves like a human. More specifically, my goal is to build an android robot called Marie Curie robot that can act like a human actor in the Portland Cyber Theater in the play Quantum Debate with a known script of every robot behavior. In order to achieve this goal, the humanoid robot need to has degrees of freedom (DOF) similar to human DOFs. Each part of the Curie robot was built to achieve the goal of building a complete humanoid robot. The important additional constraints of this project were: 1) to build the robot from available components, 2) to minimize costs, and 3) to be simple enough that the design can be replicated by non-experts, so they can create robot theaters worldwide. Furthermore, the robot appears lifelike because it executes two main behaviors like a human being. The first behavior is tracking where the humanoid robot uses a tracking algorithm to follow a human being. In other words, the tracking algorithm allows the robot to control its neck using the information taken from the vision system to look at the nearest human face. In addition, the robot uses the same vision system to track labeled objects. The second behavior is grasping where the inverse kinematics (IK) is calculated so the robot can move its hand to a specific coordinate in the surrounding space. IK gives the robot the ability to move its end-effector (hand) closer to how humans move their hands.
12

Design, modelling and simulation of 2 novel 6 DOF hybrid machines.

Shaik, Ahmed Asif. January 2012 (has links)
Industrial robot arms are an essential part of automated manufacturing, and perform tasks such as component assembly, welding, light machining, spray painting, etc. They are highly repeatable, can be calibrated to be sufficiently accurate and they eliminate human error. The serial robot architecture is by far the most ubiquitous in modern day manufacturing, as the technology is highly refined in its current state; the machine architecture provides great dexterity and it has a large useful workspace. This architecture however does have some problems, one of which is a large machine moving mass. The primary reason for this lies in the location of its motors and gearboxes. Due to the robot's significant inertia it utilizes a large amount of energy. This thesis focused on the mechanical design, mathematical modelling and simulation of 2 robotic arm designs which had a hybrid nature. They were classified as hybrid due to the fact that their architectures departed from both the classic definitions of serial kinematics manipulators/machines (SKMs) and parallel kinematics manipulators/machines (PKMs). The primary design goal was to merge some of the advantages of both architectures, i.e. a large workspace to footprint ratio and high end-effector dexterity which was found in serial robots, combined with the low inertia of a parallel robot for improved dynamics. Serial and parallel robots were complementary, and these design goals could not co-exist in a single purist robot architecture. The designs had a full complement of 6 DOFs (degrees of freedom), 3 DOFs for spatial position of the wrist and 3 DOFs for orientation of that wrist. They also had a lower machine moving mass, a fact that was thought to improve speed and energy usage. A major contribution of this research PhD project was a comparative energy usage study, which was performed against the serial robot as a measure. This was done for both hybrid designs as well as another model which represented 2 existing patented designs. The purpose of that was to determine if lowering the machine moving mass would improve energy efficiency, and to determine which design was best. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.
13

Synthèse de mouvement pour des personnages virtuels en environnements contraints / Motion planning and synthesis for virtual characters in constrained environments

Tonneau, Steve 27 February 2015 (has links)
Avec la complexité croissante des environnements virtuels apparaît le besoin de doter les personnages qui les peuplent d'une plus grande autonomie de mouvement. En plus de marcher, courir et sauter, les simulations interactives actuelles requièrent des personnages qu'ils rampent, escaladent, poussent ou tirent des objets... Ces tâches sont caractérisées par les environnements contraints dans lesquelles elles sont réalisées, qui présentent un risque fort de collision et réduisent fortement les possibilités de mouvement; elles le sont aussi par les forces importantes qui doivent être exercées afin de les réaliser, résultant de la création de contacts. Ces deux aspects rendent la synthèse automatique de mouvements très difficile dans ce contexte. Cette thèse a pour objectif de proposer une méthode automatique pour la synthèse de mouvements en environnements contraints. Pour ce faire, deux problématiques de recherche ont été posées et étudiées. La première partie de la thèse porte sur la question de la génération de contacts pertinents pour la réalisation des tâches considérées. Une nouvelle heuristique appelée EFORT (Extended FORce Transmission ratio) est présentée ; elle permet d’évaluer la compatibilité d’une posture de contact avec la tâche demandée. Cette heuristique est au coeur d’une méthode pour la génération temps réel de postures de contact. Cette méthode s’applique pour des personnages et des environnements arbitraires, et peut être directement intégrée au sein de simulations interactives telles que les jeux vidéo. La deuxième partie porte sur le problème plus global de la recherche d’une trajectoire pertinente dans un environnement contraint. Cette recherche de trajectoire passe par la recherche d’une séquence de postures de contact qui vont permettre le mouvement. Une nouvelle méthode de planification de mouvement s’appuyant sur EFORT est donc proposée. Parce qu’elle est une des premières à simultanément considérer la complexité de l’environnement et la pertinence des configurations générées au regard de la tâche à accomplir, notre méthode constitue un pas significatif vers une plus grande autonomie de mouvement pour les personnages virtuels. / With the growing complexity of virtual environments comes the need to provide virtual characters with a larger autonomy of motion. Additionally to walking, running and jumping, state of the art virtual applications require characters to climb, crawl, pull or push objects... Those tasks are characterized by the constrained environments in which they are achieved, where the risk of collision is high and motion capabilities are limited; they are also associated with important force exertion, resulting from contact creation. In this context, automatic motion synthesis is really difficult. This thesis aims at proposing an automatic method for motion synthesis in constrained environments. To achieve these goals, two research problems have been identified and studied. The first part is dedicated to the issue of generating contact postures compatible to achieve the considered tasks. We propose a new heuristic called EFORT (Extended FORce Transmission ratio). EFORT is used to evaluate the compatibility of a contact posture with the requested task. EFORT lies at the center of a new method for the real time generation of task efficient contact configurations. This generator finds its applications for arbitrary virtual characters and environment, and as such can be directly integrated within video game applications. The second part of this thesis focuses on the more global issue of computing a relevant trajectory in a constrained environment. This issue is seen as the search for a sequence of task efficient contact postures, suited for achieving the task. Consequently a new motion planner based on EFORT is proposed. Because it is one of the first to simultaneously address the complexity of the environment and task efficiency, our motion planner is a significant step towards an enhanced autonomy of motion for virtual characters.
14

Universal Event and Motion Editor for Robots' Theatre

Bhutada, Aditya 01 January 2011 (has links)
Most of work on motion of mobile robots is to generate plans for avoiding obstacles or perform some meaningful and useful actions. In modern robot theatres and entertainment robots the motions of the robot are scripted and thus the performance or behavior of the robot is always the same. In this work we want to propose a new approach to robot motion generation. We want our robot to behave more like real people. People do not move in mechanical way like robots. When a human is supposed to execute some motion, these motions are similar to one another but always slightly or not so slightly different. We want to reproduce this property based on the introduced by us new concept of probabilistic regular expression, a method to describe sets of interrelated similar actions instead of single actions. Our goal is not only to create motions for humanoid robots that will look more naturally and less mechanically, but also to program robots that will combine basic movements from certain library in many different and partially random ways. While the basic motions were created ahead of time, their combinations are specified in our new language. Although now our method is only for motions and does not take inputs from sensors into account, in future the language can be extended to input/output sequences, thus the robot will be able to adapt the motion in different ways, to some sets of sequences of input stimuli. The inputs will come from sensors, possibly attached to limbs of controlling humans from whom the patterns of motion will be acquired.
15

DESIGN AND SYSTEM IDENTIFICATION OF A MOBILE PARALLEL ROBOT

Han Lin (18516603) 08 May 2024 (has links)
<p dir="ltr">The research presents the structure and a prototype an innovative parallel robotic structure using 3 mobile bases for actuation and hybrid motion. A system identification was performed to verify the model of the robot.</p>
16

Recurrent neural networks for inverse kinematics and inverse dynamics computation of redundant manipulators.

January 1999 (has links)
Tang Wai Sum. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 68-70). / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Redundant Manipulators --- p.1 / Chapter 1.2 --- Inverse Kinematics of Robotic Manipulators --- p.2 / Chapter 1.3 --- Inverse Dynamics of Robotic Manipulators --- p.4 / Chapter 1.4 --- Redundancy Resolutions of Manipulators --- p.5 / Chapter 1.5 --- Motivation of Using Neural Networks for these Applications --- p.9 / Chapter 1.6 --- Previous Work for Redundant Manipulator Inverse Kinematics and Inverse Dynamics Computation by Neural Networks --- p.9 / Chapter 1.7 --- Advantages of the Proposed Recurrent Neural Networks --- p.11 / Chapter 1.8 --- Contribution of this work --- p.11 / Chapter 1.9 --- Organization of this thesis --- p.12 / Chapter 2 --- Problem Formulations --- p.14 / Chapter 2.1 --- Constrained Optimization Problems for Inverse Kinematics Com- putation of Redundant Manipulators --- p.14 / Chapter 2.1.1 --- Primal and Dual Quadratic Programs for Bounded Joint Velocity Minimization --- p.14 / Chapter 2.1.2 --- Primal and Dual Linear Programs for Infinity-norm Joint Velocity Minimization --- p.15 / Chapter 2.2 --- Constrained Optimization Problems for Inverse Dynamics Com- putation of Redundant Manipulators --- p.17 / Chapter 2.2.1 --- Quadratic Program for Unbounded Joint Torque Mini- mization --- p.17 / Chapter 2.2.2 --- Primal and Dual Quadratic Programs for Bounded Joint Torque Minimization --- p.18 / Chapter 2.2.3 --- Primal and Dual Linear Programs for Infinity-norm Joint Torque Minimization --- p.19 / Chapter 3 --- Proposed Recurrent Neural Networks --- p.20 / Chapter 3.1 --- The Lagrangian Network --- p.21 / Chapter 3.1.1 --- Optimality Conditions for Unbounded Joint Torque Min- imization --- p.21 / Chapter 3.1.2 --- Dynamical Equations and Architecture --- p.22 / Chapter 3.2 --- The Primal-Dual Network 1 --- p.24 / Chapter 3.2.1 --- Optimality Conditions for Bounded Joint Velocity Min- imization --- p.24 / Chapter 3.2.2 --- Dynamical Equations and Architecture for Bounded Joint Velocity Minimization --- p.26 / Chapter 3.2.3 --- Optimality Conditions for Bounded Joint Torque Mini- mization --- p.27 / Chapter 3.2.4 --- Dynamical Equations and Architecture for Bounded Joint Torque Minimization --- p.28 / Chapter 3.3 --- The Primal-Dual Network 2 --- p.29 / Chapter 3.3.1 --- Energy Function for Infinity-norm Joint Velocity Mini- mization Problem --- p.29 / Chapter 3.3.2 --- Dynamical Equations for Infinity-norm Joint Velocity Minimization --- p.30 / Chapter 3.3.3 --- Energy Functions for Infinity-norm Joint Torque Mini- mization Problem --- p.32 / Chapter 3.3.4 --- Dynamical Equations for Infinity-norm Joint Torque Min- imization --- p.32 / Chapter 3.4 --- Selection of the Positive Scaling Constant --- p.33 / Chapter 4 --- Stability Analysis of Neural Networks --- p.36 / Chapter 4.1 --- The Lagrangian Network --- p.36 / Chapter 4.2 --- The Primal-Dual Network 1 --- p.38 / Chapter 4.3 --- The Primal-Dual Network 2 --- p.41 / Chapter 5 --- Simulation Results and Network Complexity --- p.45 / Chapter 5.1 --- Simulation Results of Inverse Kinematics Computation in Re- dundant Manipulators --- p.45 / Chapter 5.1.1 --- Bounded Least Squares Joint Velocities Computation Using the Primal-Dual Network 1 --- p.46 / Chapter 5.1.2 --- Minimum Infinity-norm Joint Velocities Computation Us- ing the Primal-Dual Network 2 --- p.49 / Chapter 5.2 --- Simulation Results of Inverse Dynamics Computation in Redun- dant Manipulators --- p.51 / Chapter 5.2.1 --- Minimum Unbounded Joint Torques Computation Using the Lagrangian Network --- p.54 / Chapter 5.2.2 --- Minimum Bounded Joint Torques Computation Using the Primal-Dual Network 1 --- p.57 / Chapter 5.2.3 --- Minimum Infinity-norm Joint Torques Computation Us- ing the Primal-Dual Network 2 --- p.59 / Chapter 5.3 --- Network Complexity Analysis --- p.60 / Chapter 6 --- Concluding Remarks and Future Work --- p.64 / Publications Resulted from the Study --- p.66 / Bibliography --- p.68
17

Estudo de uma estrutura em pórtico para utilização em um veículo agrícola autônomo / Study of a portal frame structure for use in an autonomous agriculture vehicle

Rafael Rodrigues de Freitas 28 May 2008 (has links)
Avanços nas pesquisas em Veículos Agrícolas Autônomos (VAA\'s) e de Robôs Agrícolas Móveis (RAM\'s) têm sido conquistados nos últimos anos. Entretanto, um número limitado de trabalhos foca o desenvolvimento das estruturas destes veículos. O presente trabalho apresenta uma revisão de materiais encontrados na literatura e no mercado. Estudou-se modelagem cinemática de veículos autônomos que possuem configurações de suas estruturas projetadas para ter mobilidade melhorada. Estudaram-se estruturas mecânicas de máquinas que atuam em vários estádios de desenvolvimento de lavouras típicas brasileiras. Baseado no levantamento e esse estudo, foi projetado e construído um veículo com conceito modular e de pórtico para ser uma plataforma robótica no qual é utilizado para o sensoriamento em área agrícola. Uma modelagem cinemática simplificada do veículo foi realizada, fundamentada nos conceitos básicos de cinemáticas em robôs móveis. Por fim é apresentado o desenvolvimento da estrutura em pórtico do veículo. Pretende-se que o resultado auxilie no desenvolvimento de projeto de VAA\'s. / Advance on AAV (Autonomous Agriculture Vehicle) and MAR (Mobile Agriculture Robots) research are noticed in the recent years. However, a limited number of works focus in the structure development of such vehicles. This work introduces a review of the materials found in literature and market. Kinematics models of Autonomous Vehicles that have its structures designed to have mobility improved have been studied. It was studied mechanical structures of machines that act in various stages of typical brazilians crops. Based on this study and survey, a vehicle has been built with a modular concept and portal frame structure format to be used as a robotic platform in which it performs remote sensing in agricultural areas. A simplified Kinematic model have been done using basics concepts of mobile robots kinematics. At the end of this work is presented the portal frame structure development. The results obtained may assist in the design development of AAV\'s.
18

Estudo de uma estrutura em pórtico para utilização em um veículo agrícola autônomo / Study of a portal frame structure for use in an autonomous agriculture vehicle

Freitas, Rafael Rodrigues de 28 May 2008 (has links)
Avanços nas pesquisas em Veículos Agrícolas Autônomos (VAA\'s) e de Robôs Agrícolas Móveis (RAM\'s) têm sido conquistados nos últimos anos. Entretanto, um número limitado de trabalhos foca o desenvolvimento das estruturas destes veículos. O presente trabalho apresenta uma revisão de materiais encontrados na literatura e no mercado. Estudou-se modelagem cinemática de veículos autônomos que possuem configurações de suas estruturas projetadas para ter mobilidade melhorada. Estudaram-se estruturas mecânicas de máquinas que atuam em vários estádios de desenvolvimento de lavouras típicas brasileiras. Baseado no levantamento e esse estudo, foi projetado e construído um veículo com conceito modular e de pórtico para ser uma plataforma robótica no qual é utilizado para o sensoriamento em área agrícola. Uma modelagem cinemática simplificada do veículo foi realizada, fundamentada nos conceitos básicos de cinemáticas em robôs móveis. Por fim é apresentado o desenvolvimento da estrutura em pórtico do veículo. Pretende-se que o resultado auxilie no desenvolvimento de projeto de VAA\'s. / Advance on AAV (Autonomous Agriculture Vehicle) and MAR (Mobile Agriculture Robots) research are noticed in the recent years. However, a limited number of works focus in the structure development of such vehicles. This work introduces a review of the materials found in literature and market. Kinematics models of Autonomous Vehicles that have its structures designed to have mobility improved have been studied. It was studied mechanical structures of machines that act in various stages of typical brazilians crops. Based on this study and survey, a vehicle has been built with a modular concept and portal frame structure format to be used as a robotic platform in which it performs remote sensing in agricultural areas. A simplified Kinematic model have been done using basics concepts of mobile robots kinematics. At the end of this work is presented the portal frame structure development. The results obtained may assist in the design development of AAV\'s.
19

A neuro-evolutionary multiagent approach to multi-linked inverted pendulum control

Sills, Stephen 29 May 2012 (has links)
Recent work has shown humanoid robots with spinal columns, instead of rigid torsos, benefit from both better balance and an increased ability to absorb external impact. Similarly, snake robots have shown promise as a viable option for exploration in confined spaces with limited human access, such as during power plant maintenance. Both spines and snakes, as well as hyper-redundant manipulators, can simplify to a model of a system with multiple links. The multi-link inverted pendulum is a well known benchmark problem in control systems due to its ability to accommodate varying model complexity. Such a system is useful for testing new learning algorithms or laying the foundation for autonomous control of more complex devices such as robotic spines and multi-segmented arms which currently use traditional control methods or are operated by humans. It is often easy to view these systems as single-agent learners due to the high level of interaction among the segments. However, as the number of links in the system increases, the system becomes harder to control. This work replaces the centralized learner with a team of coevolved agents. The use of a multiagent approach allows for control of larger systems. The addition of transfer learning not only increases the learning rate, but also enables the training of larger teams which were previously infeasible due to extended training times. The results presented support these claims by examining neuro-evolutionary control of 3-, 6-, and 12-link systems with nominal conditions as well as with sensor noise, actuator noise, and the addition of more complex physics. / Graduation date: 2012
20

Motion planning for redundant manipulators and other high degree-of-freedom systems

Keselman, Leo 22 May 2014 (has links)
Motion planning for redundant manipulators poses special challenges because the required inverse kinematics are difficult and not complete. This thesis investigates and proposes methods for motion planning for these systems that do not require inverse kinematics and are potentially complete. These methods are also compared in performance to standard inverse kinematics based methods.

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