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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.
311

Adaptive Warning Field System

Vaidya, Varun, Bheemesh, Kushal January 2017 (has links)
This thesis is based on the work carried out in the field of safety systems for Autonomous Guided Vehicles(AGV). With autonomous vehicles being more prominent today, safe traversing of these is a major concern. The same is true for AGVs working in industry environment like forklift trucks etc. Our work applies to industrial robots. The method described here is developed by closely following an algorithm developed for safe traversing of a robot using a warning field. The report describes the literature review with work related to the safe traversing, path planning and collision avoidance in robots. The next part is dedicated to describing the methodology of implementation of the Adaptive Warning Field Method and the Dynamic Window Approach. The evaluation of the Adaptive Warning Method with the previous developed Warning Field Methods is done and test cases are designed to test the working of the designed method. Vrep simulation environment and Industrial data is used to run a simulation of the robot using the method developed in this work. We find that the method performs better compared to the previous methods in the designed scenarios. Lastly we conclude the report with the future work that can be carried out to improve and extend the algorithm.
312

Automation of depowdering step in binder-jet additive manufacturing : Commissioning of KUKA robot

Kolluri, Sowjanya January 2017 (has links)
The aim of this thesis is to automate the depowdering step in binder-jet additive manufacturing using KUKA kr6 robot. The major tasks involved in this thesis work are commissioning of the KUKA kr6 robot, plan the actions required for automation process of binder jet considering the scaling factor of green bodies. For this purpose KUKA robot with a standard KUKA compact controller (KRC4) and KUKA system software 8.3 (KSS) has been used. In Peter Corke Matlab toolbox (Matlab toolbox), KUKA kr6 robot model has been simulated to understand forward kinematics problem which shows the study the motion of end effector of robot in space for picking process. These transformations between the Joint coordinate systems and Cartesian coordinate systems give the forward and inverse kinematics. Firstly, a KUKA kr6 robot has been programmed in a KUKA Robot Language (KRL) using an algebraic approach with geometric operator to automate the picking process of green bodies. These are fragile bodies thereby many number of tests have been conducted to improve the program. Also additional effort has been placed to test the customized gripper used for the layered pick and place of the components, customized vacuum cleaner for the vacuum cleaning in between the layers and to consider the scaling factor during the sintering step of the binder jet. Finally, KUKA kr6 robot model has been simulated in Matlab toolbox. The picking point in the space has been simulated to study the forward kinematics and to understand how the robot reaches a position and orientation in space. Cartesian trajectory has been simulated. Also, the Jacobian matrix, its rank and determinant are studied to understand the singularities in KUKA kr6 robot, basing on which the thesis work can be continued and enhanced further.
313

Design och konstruktion av roterande LiDAR-system för 360 graders objektdetektering

Ask, Simon, Lindh, Rickard January 2017 (has links)
Although laser rangefinder technologies have been around for decades in military, cartography, building, industrial and research applications it is only in recent years that more generally applicable and cheaper consumer grade laser range finder sensors have become available. This project investigates the possibilities and limitations of creating a mobile 360 degree, two-dimensional obstacle detection system using off-the-shelf available electronic components. Using a Lidar Lite 3 from Garmin Ltd., an Arduino compatible microcontroller based on Atmel 328P, a Raspberry Pi 3 from The Raspberry Pi Foundation and an electronic speed controlled brushless DC motor driving the rotation, it is shown how range data measurements can be collected, communicated, processed and displayed at measurement rates between 500 and 1000 Hz. At 5 Hz update rate of a complete 360-degree data set, this translates to a worst case angular resolution of 2.5 degrees at ranges reaching 10 meters depending on target reflectivity. Configured for these faster measurement rates, at static measurements of a white painted wall, the measurements show a standard deviation of 0.06 m at a five-meter range, going up to 0.19 m at a range of 10 meters. A modular and mobile prototype was designed and built. The modularity allowed testing and verification of two configurations. Configuration A uses a slip ring for power and data transfer to the rotating sensor. Configuration B allows the laser range finder to be stationary and instead rotates a first surface aluminum mirror positioned at 45 degrees above the sensor. The measurement results show that increasing range has a notable adversely effect on the number of successful readings in a setting demanding faster measurement rates of above 500 Hz. The number of successful readings decreases at ranges above 5 meters, and this decrease of successful readings is more pronounced in the configuration using a mirror to reflect the measurement. The mirror reflected version does on the other hand allow an electromechanically simpler, more silent and durable system. Using a density based clustering algorithm it is shown how person sized objects in the point cloud data can be robustly detected at ranges up to 5 meters.
314

A Comparative Study of Process Mining Software for Supporting Bottleneck Analysis of Production Systems

Vaithianathan, Suntharaseelan January 2021 (has links)
Process mining (PM) has already found its place in analyzing and visualizing business processes across different sectors such as banking, healthcare, insurance, and logistics. However, its application is very limited in production systems. Production systems are very complex and dynamic, hindering the accurate capture of different process chain events. Generating the event log data out of the recorded events requires a proper understanding of the processes. The results of the bottleneck analysis can help the production experts to optimize the process. This study analyzes three to four PM tools to select an appropriate tool that can perform bottleneck analysis. The initial research will focus on various features of the PM tools such as modeling support, user friendliness, flexibility, stability, animation support, and BPMN modeling support. The feature analysis uses the event-log data generated from simulating the process model created in a Simulation-based Optimization tool FACTS Analyzer. Some PM tools can generate the BPMN model from the process model; animation support and modeling support features are vital for the bottleneck analysis. The PM tool's ability to create the process model automatically from the event log data can help save time involved in data collection through a physical visit to the site, conducting interviews, observations, etc. In contrast, the bottleneck analysis used simulated event log data and an event log generated from a real-world production system. The study focuses on finding whether PM can support the bottleneck analysis of the real-world production systems and find the appropriate PM tool available in the market for the same application. The use of process mining tools in the bottleneck analysis requires human intervention in identifying the bottlenecks in the process as the PM tools are incapable of recognizing them on their own. But, appropriate use of the PM tools in the bottleneck analysis can help save a considerable amount of time in manually building the simulation model. Performing iterative optimization could lead to socio, economic, and environmental sustainability as it helps avoid wastages in time, material, and energy.
315

Closed Loop Control of PMSM Motor : Field Oriented Control Using Hall Sensors

Baral, Shawon Kumar January 2021 (has links)
Fossil-fuel vehicles are one of the main causes of CO2 emissions nowadays. As we are moving toward cleaner environment electrification of vehicles are becoming more and more popular. With the environment in mind, the recent improvement in battery technology and electronics has drawn a lot of attention to Brushless DC or BLDC  motors. Due to their high torque output and robust design, BLDC motors are a popular choice as the main propulsion unit in electric vehicles.  Permanent magnet synchronous motor, PMSM, is also a brushless dc motor with minor changes in design. So the word BLDC and PMSM is used interchangeably. In this thesis, two motor control algorithms were investigated. 6-Step control and Field oriented control or FOC. A three-phase inverter allows these motors to be driven by a battery. But when battery voltage goes down the speed of the motor also goes down. This thesis investigates a method to maintain the same speed at lower dc voltage. Also running of other motors than the control system was designed for. The control system performs well in simulation for two of the motor tested with the FOC algorithm. Simulation results show that the control system can track speed and current references with minimum error. Speed controller and current controllers control each parameter independently to control the motor. Low battery simulations provide useful data that shows how the field weakening technique makes it possible to achieve higher speed at low dc voltages. / Fossildrivna fordon är en av de främsta orsakerna till koldioxidutsläpp i dag. I och med att vi går mot en renare miljö blir elektrifieringen av fordon allt mer populär. Med miljön i åtanke har den senaste tidens förbättring av batteriteknik och elektronik dragit mycket uppmärksamhet till Brushless DC- eller BLDC-motorer som ska användas som huvudframdrivningsenhet. På grund av dess höga vridmomentutgång och robusta design så är BLDC-motorer mer populära. En permanent magnetisk synkronmotor, PMSM, är också en borstlös dc-motor med mindre förändringar i designen. Så orden BLDC och PMSM används omväxlande. I denna avhandling undersöktes två motoriska styralgoritmer. 6-stegskontroll och fältorienterad kontroll eller FOC. En trefas växelriktare gör att dessa motorer kan drivas av ett batteri. Men när batterispänningen går ner går motorns hastighet också ner. Denna avhandling undersöker en metod för att bibehålla samma hastighet vid lägre likspänning, men även drift av andra motorer än vad styrsystemet var konstruerat för. Styrsystemet fungerar bra i simulering för två av de motorer som testas med FOC-algoritmen. Simuleringsresultat visar att styrsystemet kan spåra hastighet och aktuella referenser med minimalt fel. Hastighetsregulator och aktuella styrenheter kontrollerar varje parameter individuellt för att styra motorn. Simuleringar med lågt batteri ger användbara data som visar hur fältförsvagningstekniken gör det möjligt att uppnå högre hastighet vid låg likströmsspänning.
316

Evaluation of a robotic testing dashboard (RTD) used to compare autonomous robots with human pilots

Bergenholtz, Claes, Isacsson, John January 2021 (has links)
Autonomous robots are becoming a bigger part of our society. This thesis aims to evaluate a robot testing dashboard (RTD) that can be used as a new way of finding improvements when developing autonomous robots that do not use machine learning. The method that is used is design science research, which is used when creating and evaluating an artifact to address a practical problem. In our case the artifact isthe RTD. This project was performed at a company called Greenworks, which among other things develops and sells autonomous lawn mowers. The company wants to find new testing methods to help develop their autonomous lawnmowers. The RTD is created to visualize the inputs that the lawn mower utilizes to perform its tasks. A human pilot will then control the lawn mower, by only looking at that visualized data. If the pilot using the RTD can execute the same tasks as the lawn mower in its autonomous mode, the test results can be analyzed to see whether the human has done some parts of the tasks differently. The best outcome from the analysis of the test results is to find areas of improvement that can be implemented into the autonomous lawn mower design, both in software and hardware. For this purpose, an RTD was built and tested at Greenworks. From the tests using the RTD we concluded that it is helpful in the testing process, and we could find areas of improvements after analysis of our tests. However, the use of the RTD will require more time and resources compared to other methods. Each company that uses a similar dashboard concept will have to evaluate if the benefits are worth the time. Furthermore, the concept may not suit all areas of robotics but does seem to suit situations where a human can have an advantage over robots, such as in creative problem solving.
317

Processautomation med robot : En studie av möjligheter till automation av en hårdlödningsprocess / Process automation with robot : A study of possibilities to automation for a brazing process

Teodorsson, Carl-Philip January 2021 (has links)
This report is a Bachelor thesis and has been done within the area of mechanical engineering at Linköping university. The thesis has been performed as a project upon request from the company Bosch Thermoteknik AB in Tranås, Sweden. The company produces heat pumps, and in the process, brazing is used as a method to build the pipe modules the pumps contain. The brazing is currently made in terms of craftmanship in the production at the company. The purpose of this project was to investigate the possibilities to automate a brazing process and present a possible solution the company can use. The solution should mainly be based on the use of an industrial robot together with an equipment for induction heating.An iterative concept-generating process for production development was used as method to perform the project. Based on the method, a result consisting of two main areas were acquired. The first area was a study of the prerequisites for the project – the process demands and a review of the technique the resources used. The other area was the concept solution for how a brazing process can be automated.The concept itself was built by two areas. One physical part in the shape of a fixture to carry the pipe-modules during the process as well as tools and aids for the robot function. The other area was the program that forms the robot’s function. The program was based on solutions to enable identification of the modules, positioning of the robot arm with tool and a verification part to ensure the brazing has been done. The robot program was founded on a written program script to control the robot.
318

Virtual Commissioning of an industrialwood cutter machine : A software in the loop simulation

Edgar Alexander, Montero Vera January 2020 (has links)
The methods used today for the commissioning and validation of industrial machines requires theconstruction of physical prototypes. Those prototypes help the engineers to e.g. validate if theprogram code meant to control a machine works as intended. In recent years the development ofnew techniques for the commissioning and validation of industrial machines has changed rapidlythanks to the development of new software. The method used in this thesis is called simulationin the loop. Another method that can be benecial to use is hardware in the loop. Using thosemethods for the commissioning of a machine is called virtual commissioning. The simulation inthe loop method is used to simulate both the machine and the control system that operate thatmachine. This is called a digital twin, a virtual copy of the physical hardware and its control systemthat can be used without the need for a real prototype to be available.The software used in this thesis comes all from the company Siemens and those are TIA Portal,Mechatronics Concept Designer, SIMIT and PLCSim Advanced. By using those programs it waspossible to build a digital twin with rigid body dynamics and its control system of the industrialmodel that was given by the company Renholmen AB. This model contained all the necessarycomponents needed for a virtual commissioning project to be done without the need to be at thefactory oor.The results showed that it was possible to achieve a real time simulation, allowing the possibilityto trim the controller parameters without the need of a physical prototype. Design errors were alsofound thanks to the results of the simulation.This new technique has shown to be a useful tool due to most of the work could be done on a digitalmodel of the machine. Simulations can reduce the time to market for industrial machines and alsohelp engineers to validate and optimize the product at an early stage. This tool that can be usedto validate industrial machines before they are created.
319

Evaluating Multi-Uav System with Text to Spech for Sitational Awarness and Workload

Lindgren, Viktor January 2021 (has links)
With improvements to miniaturization technologies, the ratio between operators required per UAV has become increasingly smaller at the cost of increased workload. Workload is an important factor to consider when designing the multi-UAV systems of tomorrow as too much workload may decrease an operator's performance. This study proposes the use of text to speech combined with an emphasis on a single screen design as a way of improving situational awareness and perceived workload. A controlled experiment consisting of 18 participants was conducted inside a simulator. Their situational awareness and perceived workload was measured using SAGAT and NASA-TLX respectively. The results show that the use of text to speech lead to a decrease in situational awareness for all elements inside the graphical user interface that were not directly handled by a text to speech event. All of the NASA-TLX measurements showed an improvement in perceived workload except for physical demand. Overall an improvement of perceived workload was observed when text to speech was in use.
320

APPLYING UAVS TO SUPPORT THE SAFETY IN AUTONOMOUS OPERATED OPEN SURFACE MINES

Hamren, Rasmus January 2021 (has links)
Unmanned aerial vehicle (UAV) is an expanding interest in numerous industries for various applications. Increasing development of UAVs is happening worldwide, where various sensor attachments and functions are being added. The multi-function UAV can be used within areas where they have not been managed before. Because of their accessibility, cheap purchase, and easy-to-use, they replace expensive systems such as helicopters- and airplane-surveillance. UAV are also being applied into surveillance, combing object detection to video-surveillance and mobility to finding an object from the air without interfering with vehicles or humans ground. In this thesis, we solve the problem of using UAV on autonomous sites, finding an object and critical situation, support autonomous site operators with an extra safety layer from UAVs camera. After finding an object on such a site, uses GPS-coordinates from the UAV to see and place the detected object on the site onto a gridmap, leaving a coordinate-map to the operator to see where the objects are and see if the critical situation can occur. Directly under the object detection, reporting critical situations can be done because of safety-distance-circle leaving warnings if objects come to close to each other. However, the system itself only supports the operator with extra safety and warnings, leaving the operator with the choice of pressing emergency stop or not. Object detection uses You only look once (YOLO) as main object detection Neural Network (NN), mixed with edge-detection for gaining accuracy during bird-eye-views and motion-detection for supporting finding all object that is moving on-site, even if UAV cannot find all the objects on site. Result proofs that the UAV-surveillance on autonomous site is an excellent way to add extra safety on-site if the operator is out of focus or finding objects on-site before startup since the operator can fly the UAV around the site, leaving an extra-safety-layer of finding humans on-site before startup. Also, moving the UAV to a specific position, where extra safety is needed, informing the operator to limit autonomous vehicles speed around that area because of humans operation on site. The use of single object detection limits the effects but gathered object detection methods lead to a promising result while printing those objects onto a global positions system (GPS) map has proposed a new field to study. It leaves the operator with a viewable interface outside of object detection libraries.

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