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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.
771

En studie av en industrirobots beteende vid borrning / A study of the behaviour of an Industrial Robot during drilling

Svernestam, Jonas January 2005 (has links)
In the assembly process of airframe structures there are many drilled holes and on some parts the holes are mainly drilled manually with pneumatic handheld drilling machines. During conventional drilling in metal, burrs appear. To remove these burrs the parts of the structure must be separated and deburred before they can be put together for fastening. This is a time consuming measure and therefore expensive. To facilitate this process and lower production costs some parts of the process needs to be automated. A part of this thesis was a project in co-operation with Saab, Novator, Specma Automation and the University of Linköping. The purpose of this project was to investigate the ability of an industrial robot to drill holes in aeroplane structures using orbital drilling. How the project tests were carried out and the results of these tests are presented in the first part of this thesis. The tests showed that slip-stick appeared when a force was applied on the working object by the robot. Because of the movement of the pressure foot the drilled hole will be in the wrong position and if the movement appears during drilling the quality of the hole is being poor. Several different tests were performed using different amounts of forces and different pressure feet trying to prevent slip-stick from appearing. Finally tests were performed with good results concerning the quality of the holes. In the second part of this thesis the proceeding tests that were carried out are presented. The purpose of these tests was to find out how the robot acts when a static pressure is applied on a work object by the robot and try to find out what the cause of the slip-stick was. Several tests were done where the robot applied a force on several different points on the fixture and the slip-stick was measured. The tests that were carried out during this thesis showed that an industrial robot can be used to drill holes in aeroplane structures. To make sure that the quality of the drilled holes is sufficient for the high demands of the aeroplane industry the working area of the robot is limited to a small area in front of the robot. The slip-stick that appears when the robot is extended into a position on the far side of the robot is too large for the robot to drill the hole in an accurate position. / Vid flygplansmontering borras det många olika hål och på vissa delar borras större delen av dessa hål manuellt med pneumatiska handborrmaskiner. Vid konventionell borrning i metall bildas oönskade grader. Strukturen plockas därför isär så att graderna kan tas bort innan strukturens delar kan passas samman igen för att sammanfogas. Detta är en tidskrävande åtgärd och därmed dyr och i ett steg att förenkla denna process och få en billigare produktion vill man automatisera vissa steg i denna process. En del av detta examensarbete var ett projekt i samarbete med Saab, Novator, Specma Automation och Linköpings Universitet vars syfte var att klargöra en robots förmåga att borra hål i flygplansmaterial med orbitalborrningsteknik. I första delen av detta examensarbete redovisas genomförande och resultat av projektets tester. Testerna visade att tryckfoten gled på testmaterialets yta när roboten lade en tryckkraft på testplåten, så kallad slip-stick uppkom. Denna glidning gör att det borrade hålet inte hamnar på rätt position och sker glidningen under borroperationen så försämras hålets kvalité. Flera olika tester gjordes med varierad tryckkraft och med olika tryckfötter för att försöka förhindra att slip-stick uppkom. Tester genomfördes där hål borrades med bra kvalité. I den andra delen av denna rapport redovisas fortsättningen på examensarbetet som var en vidareundersökning av de tidigare genomförda testerna. Syftet med denna del var att undersöka hur en industrirobot beter sig när den används för att lägga på en tryckkraft mot ett material samt att försöka ta reda på vad som är orsaken till slip-sticken. Fler tester gjordes där roboten tryckte på olika punkter på en fixtur och de uppkomna slip-sticken mättes upp. Testerna under detta examensarbete har visat att det går att använda en industrirobot till att borra hål i flyglansmaterial. För att kvaliteten på de borrade hålen ska klara de höga krav som ställs inom flygplansindustrin är robotens arbetsområde begränsat till ett litet fönster mitt framför roboten. De glidningar som uppkommer när robotarmen är utsträckt långt åt sidan om roboten är alldeles för stora för de positioneringskrav som är på hålens placering på flygplansstrukturen.
772

Sensorsystem till hinderhanterande robot / Sensor System for Obstacle Handling Robot

Lichtermann, Johan January 2005 (has links)
The projects goal is to construct and program a robot that is controlled from a computer but also have an obstacle handling function that allows the robot to navigate around the object by itself. The robot is a simple construction and the number of components and functions is kept at a minimum. A tricycle construction was chosen because it’s the simplest. Communication between the robot and the computer also kept as simple as possible. / Målet med projektet är att konstruera och programmera en robot som går att styra från en dator men det skall även finnas en hinderhanterande funktion som gör att roboten kan åka runt hinder av sig själv. Roboten är en enkel konstruktion där antalet komponenter och funktioner hålls nere till ett minimum. En trehjuling valdes då det är den enklaste konstruktionen. Kommunikationen mellan roboten och datorn hålls också så enkel som möjligt.
773

Design of a Multiple-User Intelligent Feeding Robot for Elderly and Disabled

Pourmohammadali, Homeyra 17 May 2007 (has links)
The number of elderly people around the world is growing rapidly. This has led to an increase in the number of people who are seeking assistance and adequate service either at home or in long-term- care institutions to successfully accomplish their daily activities. Responding to these needs has been a burden to the health care system in terms of labour and associated costs and has motivated research in developing alternative services using new technologies. Various intelligent, and non-intelligent, machines and robots have been developed to meet the needs of elderly and people with upper limb disabilities or dysfunctions in gaining independence in eating, which is one of the most frequent and time-consuming everyday tasks. However, in almost all cases, the proposed systems are designed only for the personal use of one individual and little effort to design a multiple-user feeding robot has been previously made. The feeding requirements of elderly in environments such as senior homes, where many elderly residents dine together at least three times per day, have not been extensively researched before. The aim of this research was to develop a machine to feed multiple elderly people based on their characteristics and feeding needs, as determined through observations at a nursing home. Observations of the elderly during meal times have revealed that almost 40% of the population was totally dependent on nurses or caregivers to be fed. Most of those remaining, suffered from hand tremors, joint pain or lack of hand muscle strength, which made utensil manipulation and coordination very difficult and the eating process both messy and lengthy. In addition, more than 43% of the elderly were very slow in eating because of chewing and swallowing problems and most of the rest were slow in scooping and directing utensils toward their mouths. Consequently, one nurse could only respond to a maximum of two diners simultaneously. In order to manage the needs of all elderly diners, they required the assistance of additional staff members. The limited time allocated for each meal and the daily progression of the seniors’ disabilities also made mealtime very challenging. Based on the caregivers’ opinion, many of the elderly in such environments can benefit from a machine capable of feeding multiple users simultaneously. Since eating is a slow procedure, the idle state of the robot during one user’s chewing and swallowing time can be allotted for feeding another person who is sitting at the same table. The observations and studies have resulted in the design of a food tray, and selection of an appropriate robot and applicable user interface. The proposed system uses a 6-DOF serial articulated robot in the center of a four-seat table along with a specifically designed food tray to feed one to four people. It employs a vision interface for food detection and recognition. Building the dynamic equations of the robotic system and simulation of the system were used to verify its dynamic behaviour before any prototyping and real-time testing.
774

A Platform for Robot-Assisted Intracardiac Catheter Navigation

Ganji, Yusof January 2009 (has links)
Steerable catheters are routinely deployed in the treatment of cardiac arrhythmias. During invasive electrophysiology studies, the catheter handle is manipulated by an interventionalist to guide the catheter's distal section toward endocardium for pacing and ablation. Catheter manipulation requires dexterity and experience, and exposes the interventionalist to ionizing radiation. Through the course of this research, a platform was developed to assist and enhance the navigation of the catheter inside the cardiac chambers. This robotic platform replaces the interventionalist's hand in catheter manipulation and provides the option to force the catheter tip in arbitrary directions using a 3D input device or to automatically navigate the catheter to desired positions within a cardiac chamber by commanding the software to do so. To accomplish catheter navigation, the catheter was modeled as a continuum manipulator, and utilizing robot kinematics, catheter tip position control was designed and implemented. An electromagnetic tracking system was utilized to measure the position and orientation of two key points in catheter model, for position feedback to the control system. A software platform was developed to implement the navigation and control strategies and to interface with the robot, the 3D input device and the tracking system. The catheter modeling was validated through in-vitro experiments with a static phantom, and in-vivo experiments on three live swines. The feasibility of automatic navigation was also veri ed by navigating to three landmarks in the beating heart of swine subjects, and comparing their performance with that of an experienced interventionalist using quasi biplane fluoroscopy. The platform realizes automatic, assisted, and motorized navigation under the interventionalist's control, thus reducing the dependence of successful navigation on the dexterity and manipulation skills of the interventionalist, and providing a means to reduce the exposure to X-ray radiation. Upon further development, the platform could be adopted for human deployment.
775

Human-Inspired Robot Task Teaching and Learning

Wu, Xianghai 28 October 2009 (has links)
Current methods of robot task teaching and learning have several limitations: highly-trained personnel are usually required to teach robots specific tasks; service-robot systems are limited in learning different types of tasks utilizing the same system; and the teacher’s expertise in the task is not well exploited. A human-inspired robot-task teaching and learning method is developed in this research with the aim of allowing general users to teach different object-manipulation tasks to a service robot, which will be able to adapt its learned tasks to new task setups. The proposed method was developed to be interactive and intuitive to the user. In a closed loop with the robot, the user can intuitively teach the tasks, track the learning states of the robot, direct the robot attention to perceive task-related key state changes, and give timely feedback when the robot is practicing the task, while the robot can reveal its learning progress and refine its knowledge based on the user’s feedback. The human-inspired method consists of six teaching and learning stages: 1) checking and teaching the needed background knowledge of the robot; 2) introduction of the overall task to be taught to the robot: the hierarchical task structure, and the involved objects and robot hand actions; 3) teaching the task step by step, and directing the robot to perceive important state changes; 4) demonstration of the task in whole, and offering vocal subtask-segmentation cues in subtask transitions; 5) robot learning of the taught task using a flexible vote-based algorithm to segment the demonstrated task trajectories, a probabilistic optimization process to assign obtained task trajectory episodes (segments) to the introduced subtasks, and generalization of the taught task trajectories in different reference frames; and 6) robot practicing of the learned task and refinement of its task knowledge according to the teacher’s timely feedback, where the adaptation of the learned task to new task setups is achieved by blending the task trajectories generated from pertinent frames. An agent-based architecture was designed and developed to implement this robot-task teaching and learning method. This system has an interactive human-robot teaching interface subsystem, which is composed of: a) a three-camera stereo vision system to track user hand motion; b) a stereo-camera vision system mounted on the robot end-effector to allow the robot to explore its workspace and identify objects of interest; and c) a speech recognition and text-to-speech system, utilized for the main human-robot interaction. A user study involving ten human subjects was performed using two tasks to evaluate the system based on time spent by the subjects on each teaching stage, efficiency measures of the robot’s understanding of users’ vocal requests, responses, and feedback, and their subjective evaluations. Another set of experiments was done to analyze the ability of the robot to adapt its previously learned tasks to new task setups using measures such as object, target and robot starting-point poses; alignments of objects on targets; and actual robot grasp and release poses relative to the related objects and targets. The results indicate that the system enabled the subjects to naturally and effectively teach the tasks to the robot and give timely feedback on the robot’s practice performance. The robot was able to learn the tasks as expected and adapt its learned tasks to new task setups. The robot properly refined its task knowledge based on the teacher’s feedback and successfully applied the refined task knowledge in subsequent task practices. The robot was able to adapt its learned tasks to new task setups that were considerably different from those in the demonstration. The alignments of objects on the target were quite close to those taught, and the executed grasping and releasing poses of the robot relative to objects and targets were almost identical to the taught poses. The robot-task learning ability was affected by limitations of the vision-based human-robot teleoperation interface used in hand-to-hand teaching and the robot’s capacity to sense its workspace. Future work will investigate robot learning of a variety of different tasks and the use of more robot in-built primitive skills.
776

Design, Fabrication and Control of a Magnetic Capsule Robot for the Human Esophagus

Hosseini, Saman 18 February 2010 (has links)
Biomedical engineering is the application of engineering principles and techniques to the medical field. It combines the design and problem solving skills of engineering with medical and biological sciences to improve healthcare diagnosis and treatment. As the result of improvements in robotics and micro technology science in the 20th century, micro electromechanical system technology has joined with medical applications which results in micro robotic medical applications. Drug delivery is one of the most important and controversial topics which scientists and engineers have tried to improve in medical applications. For diseases like cancer, localized drug delivery is a highlight target involving bombarding a small area of a human’s body and this technology has not been completely achieved yet. The ultimate objective of this thesis is the development of wireless capsule robot controlled by a magnetic drive unit. A magnetic drive unit is a system that consists of electromagnets, which produce the magnetic field from outside of the patient’s body. The capsule robot, which is the slave robot in the system, moves inside a human’s gastrointestinal tract. This project is focused mainly on a human esophagus and all the experiments are done in a prototype of the human’s esophagus. Drug delivery for diseases like cancer is the objective of the capsule robot. The proposed design consists of a slave permanent magnet for the motion of capsule robot in a tube, a reservoir of drug, and a micro mechanical mechanism for drug release. The capsule robot is fabricated and developed in a 12mm length and 5mm diameter with the weight of 1.78 grams without the built-in permanent magnet. The drug delivery system is a semi-magnetized system, which can be controlled by an external magnetic field. It consists of a mechanical plunger and spring, which can be open and close through an external magnetic field manipulation. The amount of drug for a desired location can be controlled by manipulating the external magnetic field. To achieve this target, analytical modeling is conducted. A numerical simulation and an experimental setup demonstrate that a capsule robot in a human esophagus in a simple and multi channel system. Horizontal control is set for the capsule robot, using a custom-designed controller and a colored liquid is released with the external magnetic field. The present study with its fabricated prototype is a research is this area to prove the concept of wireless control of a robot inside a human body and the potential for a drug delivery system. It is expected that the results achieved in this project will help realize and promote capsule robot for medical treatments.
777

Quadrotor Position Estimation using Low Quality Images

Gariepy, Ryan January 2011 (has links)
The use of unmanned systems is becoming widespread in commercial and military sectors. The ability of these systems to take on dull, dirty, and dangerous tasks which were formerly done by humans is encouraging their rapid adoption. In particular, a subset of these undesirable tasks are uniquely suited for small unmanned aerial vehicles such as quadrotor helicopters. Examples of such tasks include surveillance, mapping, and search and rescue. Many of these potential tasks require quadrotors to be deployed in environments where a degree of position estimation is required and traditional GPS-based positioning technologies are not applicable. Likewise, since unmanned systems in these environments are often intended to serve the purpose of scouts or first--responders, no maps or reference beacons will be available. Additionally, there is no guarantee of clear features within the environment which an onboard sensor suite (typically made up of a monocular camera and inertial sensors) will be able to track to maintain an estimate of vehicle position. Up to 90% of the features detected in the environment may produce motion estimates which are inconsistent with the true vehicle motion. Thus, new methods are needed to compensate for these environmental deficiencies and measurement inconsistencies. In this work, a RANSAC-based outlier rejection technique is combined with an Extended Kalman Filter (EKF) to generate estimates of vehicle position in a 2--D plane. A low complexity feature selection technique is used in place of more modern techniques in order to further reduce processor load. The overall algorithm was faster than the traditional approach by a factor of 4. Outlier rejection allows the abundance of low quality, poorly tracked image features to be filtered appropriately, while the EKF allows a motion model of the quadrotor to be incorporated into the position estimate. The algorithm is tested in real-time on a quadrotor vehicle in an indoor environment with no clear features and found to be able to successfully estimate position of the vehicle to within 40 cm, superior to those produced when no outlier rejection technique was used. It is also found that the choice of simple feature selection approaches is valid, as complex feature selection approaches which may take over 10 times as long to run still result in outliers being present. When the algorithm is used for vehicle control, periodic synchronization to ground truth data was required due to nearly 1 second of latency present in the closed--loop system. However, the system as a whole is a valid proof of concept for the use of low quality images for quadrotor position control. The overall results from the work suggest that it is possible for unmanned systems to use visual data to estimate state even in operational environments which are poorly suited for visual estimation techniques. The filter algorithm described in this work can be seen as a useful tool for expanding the operational capabilities of small aerial vehicles.
778

A Novel Approach for Performance Assessment of Human-Robotic Interaction

Abou Saleh, Jamil 16 March 2012 (has links)
Robots have always been touted as powerful tools that could be used effectively in a number of applications ranging from automation to human-robot interaction. In order for such systems to operate adequately and safely in the real world, they must be able to perceive, and must have abilities of reasoning up to a certain level. Toward this end, performance evaluation metrics are used as important measures. This research work is intended to be a further step toward identifying common metrics for task-oriented human-robot interaction. We believe that within the context of human-robot interaction systems, both humans' and robots' actions and interactions (jointly and independently) can significantly affect the quality of the accomplished task. As such, our goal becomes that of providing a foundation upon which we can assess how well the human and the robot perform as a team. Thus, we propose a generic performance metric to assess the performance of the human-robot team, where one or more robots are involved. Sequential and parallel robot cooperation schemes with varying levels of task dependency are considered, and the proposed performance metric is augmented and extended to accommodate such scenarios. This is supported by some intuitively derived mathematical models and some advanced numerical simulations. To efficiently model such a metric, we propose a two-level fuzzy temporal model to evaluate and estimate the human trust in automation, while collaborating and interacting with robots and machines to complete some tasks. Trust modelling is critical, as it directly influences the interaction time that should be directly and indirectly dedicated toward interacting with the robot. Another fuzzy temporal model is also presented to evaluate the human reliability during interaction time. A significant amount of research work stipulates that system failures are due almost equally to humans as to machines, and therefore, assessing this factor in human-robot interaction systems is crucial. The proposed framework is based on the most recent research work in the areas of human-machine interaction and performance evaluation metrics. The fuzzy knowledge bases are further updated by implementing an application robotic platform where robots and users interact via semi-natural language to achieve tasks with varying levels of complexity and completion rates. User feedback is recorded and used to tune the knowledge base where needed. This work intends to serve as a foundation for further quantitative research to evaluate the performance of the human-robot teams in achievement of collective tasks.
779

Motion Control of 3 Degree-Of-Freedom Direct-Drive Robot

Gullayanon, Rutchanee 18 April 2005 (has links)
Modern motion controllers of robot manipulators require knowledge of the system's dynamics in order to intelligently predict the torque command. The main objective for this thesis is to apply various motion controllers on a parallel direct drive robot in simulations and verify if one can take advantage of the model knowledge to improve performance of controllers. The controllers used in this thesis varied from simple PD control with position and velocity reference only applied independently at each joint to more advanced PD control with full dynamic feedforward term and computed torque control, which incorporate full dynamic knowledge of the manipulator. In the first part, a thorough study of deriving dynamic equation using Lagrange formulation has been presented as well as the actual derivation of dynamic equations for MINGUS2000. Next, in order to prepare proper sets of inputs for the simulations, detailed discussions of end effector trajectory path planning and inverse kinematics determination have been presented. Finally, background theories of various controllers used in this thesis have been presented and their simulation results on the closed-chain direct drive robot have been compared for verification purposes.
780

Implementation of A Swing System Based on Fuzzy Control

Si Tou, Tat-seng 11 August 2011 (has links)
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