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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.
71

Concept and simulation of robotized assembly application

Tullock, Hanna January 2018 (has links)
Assa OEM is a manufacturer of locks and fittings for windows, doors and cabinets. To be more competitive, automating the production is an advantage. Assa assembles six different types of left and right reversible hinges. One product stands for 80 % of the assembly time on the line. For this product Assa wants to implement a robotized assembly solution in one of the three assembly stations. The remaining 20% still needs to be assembled manually. The aim of this study is to investigate three assembly stations, select one assembly station to automate, give three concepts at half-time of the project for the selected assembly station and simulate one final automated concept. The assembly line produces approximately 2000 reversible hinges each day. For the stations in the assembly line the cycle time is around 16 seconds. In the three assembly stations the assembly tasks are similar, it is the number of rivets or parts that differ. In assembly station three there is one additional task that is not included in the first two assembly stations. In this task the arm is lifted and turned 180 degrees, and then placed over three rivets. This is more complex for a robot to perform and will require more equipment. There are similarities between assembly station one and two and therefore concepts for both stations will be given. Three layout concepts are presented for the first assembly station and for the second assembly station one concept is presented. Also, two concepts of combining assembly station one and two are presented. On April 17th, 2018, a meeting at Assa was held to discuss the different concepts and layouts. The discussion led to the conclusion that a further investigation on implementing a robot will be carried out for the concept in assembly station two. The main result is that the cycle time of 16 seconds is difficult to accomplish. The path must be well planned to achieve this with a collaborative robot. To attain the cycle time the end-effector must be designed so that no tool change will be necessary. The rivet is small and therefore a gripper would have difficulty gripping the rivets. Therefore, other methods such as ferromagnetic or vacuum are recommended. The feeder system of the rivet is suggested to have a vibrating bowl feeder due to the orientation of the rivets. The frames’ feeder system needs to be designed for the purpose in assembly station two. The frame that is to be assembled on to the fixture exposes a risk for an operator if working beside the robot. To minimize the risk area from the frame, relocation of the frame feeder and planning the path differently is suggested. The layout will require safety equipment and the suitable safety equipment depends on the flexibility Assa requires.
72

A Flexible, Low-cost Approach to Slippage Detection using Pyroelectricity

Larsson, Anders Robin January 2020 (has links)
Myoelectric prosthesis on the market today are mostly very expensive and rarely allow the amputee any feedback, leaving the users separated from their own robotic arm. Integrating sensory systems into an arm which needs to be replaced several times during a lifetime may also not be cost efficient. With a sensory system tted in a removable and re-sizeable glove, the sensory system will not require a replacement unless broken. Using a exible, durable, low-cost material, sensitive to both change in pressure and temperature, this may be achieved. Using the pyroelectric properties of thin-film Polyvinylidene Fluoride, a sensor able to detect the incipient of slippage and its initial direction is achieved.
73

Kalibreringsstation : Kalibrering av pallgafflar

Johansson, Mattias, Bengtsson, Ander January 2020 (has links)
The work is about designing a calibration station as an integral component of a company's existing product. The product is a robotic cell that automates the production of pallets. The purpose of the calibration station is to rectify an angular error that occurs on the pallet forks, which is mounted on the robot's tool, whose task is to lift and stack the pallets the robot cell manufactures. The company has theories as to why the angular error occurs and believes that there are a number of factors that influence. The purpose of the calibration station is to be able to calibrate the pallet forks when an angular error occurs and to correct all rotations and translations within an approved tolerance. Methods used to carry out the work are to study the problem and investigate how others have solved similar problems and to gather knowledge in the area of ​​calibration. The calibration station design and sensors are evaluated and discussed to determine which sensor and design will solve the task. Algorithms are programmed to find, calculate and correct angular errors that have occurred. The result of the calibration station that has been designed shows that it works for angular errors less than ten degrees in rotation and for translation in millimeters. After a calibration has been performed on the pallet forks, the result of the calibration falls within the requirements of the tolerances specified in the work. The work concludes with an evaluation of how the calibration station can be developed to perform better. / Arbetet handlar om att konstruera en kalibreringsstation som en ingående komponent i ett företags befintliga produkt. Produkten är en robotcell som automatiserar tillverkningen av pallar. Kalibreringsstationens syfte är att åtgärda ett vinkelfel som uppstår på pallgafflarna, som sitter på robotens verktyg, vars uppgift är att lyfta och stapla de pallar robotcellen tillverkar. Företaget har teorier om varför vinkelfelet uppstår och menar att det är ett flertal faktorer som påverkar. Kalibreringsstationens mål är att kunna kalibrera pallgafflarna när ett vinkelfel uppstår och korrigera alla rotationer och translationer inom en godkänd tolerans. Metoder som används för att genomföra arbetet är att studera problemet och undersöka hur andra har löst liknande problem samt samla kunskap inom området kalibrering. Kalibreringsstationens design samt sensorer utvärderas och diskuteras, för att komma fram till vilken sensor och design som skall lösa uppgiften. Algoritmer programmeras för att hitta, beräkna och korrigera vinkelfel som har uppstått. Resultatet för kalibreringsstationen som har konstruerats visar att den fungerar för vinkelfel mindre än tiotal grader i rotation samt för translation i millimeter. Efter att en kalibrering har utförts på pallgafflarna hamnar resultatet av kalibreringen inom kraven på toleranserna som angivits i arbetet. Arbetet avslutas med en utvärdering hur kalibreringsstationen kan utvecklas för att prestera bättre.
74

Understanding and communicating intentions in human-robot interaction

Morvan, Jérémy January 2015 (has links)
This thesis is about the collaboration and interaction between a robot and a human agent. The goal is to use the robot as a coworker, by implementing the premises of an interaction system that would make the interaction as natural as possible. This involves that the robot has a vision system that allows understanding of the intentions of the human. This thesis work is intended to be part of a larger project aimed at extending the competences of the programmable industrial robot, Baxter, made by Rethink Robotics. Due to the limited vision abilities of this robot, a Kinect camera is added on the top of its head. This thesis covers human gestures recognition through the Kinect data and robot reactions to these gestures through visual feedback and actions.
75

Road Condition Analysis For Autonomous Haulers

Söderlund, Karl, Friberg, Simon January 2023 (has links)
With autonomous vehicles becoming more common and established, there are some problems to overcome before their full potential can be reached. One of these problems is the lack of information about the condition of the road, which traditionally would be acquired from the driver operating the vehicle. Volvo Autonomous Solutions are developing an autonomous hauler, made for operating in off-road workplaces, such as quarries and mines. In these off-road workplaces, road maintenance is limited and often performed only when deemed necessary by a driver. This thesis investigates the issue of detecting irregularities in the road on an autonomous vehicle. To achieve this data from an Inertial Measurement Unit (IMU) and a Global Navigation Satellite System (GNSS) unit mounted on the vehicle is collected, analysed, and classified to find any irregularities in the road. In order to improve confidence in the classification of the irregularities, false positives are reduced by using an occupancy grid solution. The results show that the use of IMU data can be used to detect irregularities and that the use of an occupancy grid increases the confidence of detected irregularities.
76

Teleoperation of an Autonomous Ground-Penetrating Radar for Non-Destructive Surveying: Design and Implementation

Beyer, Rasmus January 2023 (has links)
A lot of features that need to be scanned underground should not be disturbed, from waterlines to unmarked graves. A non-invasive way of probing underground is Ground-Penetrating Radar (GPR). GPR finds differences in materials with radar waves. However, GPR is human-operated and its position is generally determined with a GPS. In some cases, the presence of a human operator can be dangerous, and in other cases, the GPS is not reliable (i.e. mines, glaciers). Therefore there are situations where an autonomous and non-GPS-reliant solution is preferable. The current state of the autonomous GPR system targeted in this work has a non-intuitive GUI that requires an experienced hand to operate. I present an updated hardware and software platform with an intuitive GUI. This updated autonomous system continuously builds a map of its surroundings with Simultaneous Mapping And Localization (SLAM). SLAM localizes itself within the map through sensor-fused position estimates. After the survey is completed the positions are saved and integrated with radar data to be visualized. Robot Operating System 2 (ROS2) is the software I used that allows communications between hardware components, software systems, and the GUI. The new hardware package uses only one source of power and is built using quick connectors that allow for quick removal from the GPR platform. This system allows for intuitive autonomous survey planning and execution in any field paired with a simple way of visualizing data.
77

Development of an Automatic Control Platform for Food Waste Management

Modin, Ivan January 2021 (has links)
According to the facts presented by The United Nations in their 12th goal - ensure sustainable consumption and production patterns - of the 17 sustainability goals, an estimated third of all food produced each year ends up wasted, in the bins of consumers and retailers or spoiling, due to poor transportation and harvesting practices. Reducing food waste is therefore one of the indispensable tasks to accomplish this goal.   This degree project aims to develop, as proof of concept, an automatic control platform for food waste management and implement it in a form of a prototype. The platform is intended to handle the workflow automatically, taking in food waste, weighing it, getting it photographed for image recognition and transporting it to a specified bin according to the classification of food waste using image recognition. The classification part is, however, not included in this project.    The prototype of the control platform consists of a mechanical construction, a weighing scale, a stepper motor, a servomotor and a Raspberry Pi single-board computer. The mechanical construction was designed using CAD (computer aided design) and made with a 3D printer. On the top of the construction is an open flat platform, for placing food waste, which has two walls on the sides, one opening in the front and a robot arm in the back. The robot arm is moved forward, to offload food waste, and backward by a servomotor. The platform is mounted a base with a stand which supports the mechanical construction. It is rotated using a stepper motor installed in the base and stops at three different postions at 90, 180 and 270 degrees, respectively, which are to represent the three different categories of food waste that is to be classified using image recognition. The Raspberry Pi is the controller that is programmed to coordinate the whole workflow.   The prototype is finished and tested. The test results have shown that it works well as a control platform that can handle the workflow, starting at the position to take in food waste, then weighing it and transporting it to three different specified positions, respectively.
78

Digitalized contract definition and negotiations for the agreement of rights and obligations in electronic auctions

Chiquito, Eric January 2022 (has links)
Negotiations of different kinds are used to trade goods and services. Within these, the creation of a signed agreement or contract that is binding for the agreeing parties helps also the gathering of evidence that can be used in case of disputes and for adjudication. Traditionally, contracts are established on paper agreements that are signed by all the involved parties and by a law enforcement entity that ensure its legality in a court of law. These contracts have evolved with the introduction of Information Technology (IT) where the negotiation of goods and services is mainly virtual and/or automatized. The consistency and processing time of the computers allow for negotiations to be more efficient than ever.  Digitalized negotiations allow for auctioning systems providing a mechanism to efficiently match demand and supply in the exchange of goods and services. Such suctioning systems allow multiple users to iteratively or non-iteratively compete against one another to achieve allocative efficiency. Lately, digitalized auctions are implemented using Blockchain systems with the use of Smart Contracts to archieve decentralization. These are implemented as a digital script that may encode any set of rules written as code, with the validity of the code being enforced by the Blockchain's consensus mechanism. These Smart Contracts computations however tend to be expensive when executed and limited by the blocksize.   This thesis studies the creation of digitized negotiation protocols and contract definition following the needs of traditional trading and auctioning systems. We investigate the use of Ricardian Contracts for flexible representation of rights and obligations of entities in the context of circular economy in both single and multi-attribute auctions. We analyze the implication of digitized agreements in the context of data sharing. Furthermore, we analyze how usage control policies can be represented into Ricardian Contracts in the context of intellectual property protection, compliance with regulations, and digital rights management.Finally, we analyze the properties that a system that supports the mentioned models should have and how to implement it in the context of distributed auctioning systems by contrasting available state-of-the-art.  The main contributions of the thesis are: (1) The creation of a multi-attribute auctioning protocol for the circular economy which implements Ricardian Contracts for the representation of rights and obligations. (2) A method to negotiate obligations and access provisions with multi-level Ricardian contracts, and automatically enforce those provisions with access control. (3) A state-of-art analysis on distributed and decentralized auctioning systems where the key properties of auctioning systems are identified and are evaluated against the current implementations.
79

Routing of autonomous vehicles with lane change possibilities

Raveendran, Vishnu Pradheep January 2021 (has links)
An autonomous vehicle has to understand the surrounding dynamic environment to make the driving decisions such as lane change by giving way to the dynamic obstacles. Motion planning is a challenging problem for an autonomous vehicle while changing a lane in the complex dynamic environment, as the optimal solution for routing must be computed in real time. This thesis provides a framework for an autonomous vehicle to analyse the lane change possibilities. Information from the digital map and estimation of the surrounding objects evaluate a method to find the trajectory for a lane change. The method involves constrained optimization problem of trajectory planning by incorporating interpolated optimal route as the sampling points. Numerical simulations show the effectiveness of the proposed technique in a scenario emulating a driving context for the autonomous vehicle. The result shows that, in a complex dynamic environment, the innovation of deploying model of the road descriptions, graph search and trajectory planning together makes the proposed method far better than the other methods applied in the researches done before for the lane change.
80

Localization and Mapping for Outdoor Mobile Robots with RTK GPS and Sensor Fusion : An Investigation of Sensor Technologies for the Automower Platform

Stenbeck, Filip, Lobell, Oden January 2017 (has links)
The following thesis addresses the problem of localizing an outdoor mobile robot and mapping the environment using the state of the art of consumer grade RTK GPS. The thesis investigates limitations and possibilities for sensor fusion to increase reliability and usability. The main subject of research is a robotic lawn mower from Husqvarna, the Automower 430x, connected to existing hardware on the product with an auxiliary real time kinematic global positioning system, the Emlid Reach. The test conducted showed that the auxiliary RTK GPS module is currently unsatisfactory as sole absolute position sensor for the Automower platform, mainly due to inconsistent performance. This thesis is meant as a preliminary study for future use of GNSS sensors for outdoor mobile robots and as a suggestive study of the current performance of the increasingly popular Emlid Reach GPS module.

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