{"id":{"repo_id":"freiburg-diss","oai_identifier":"oai:freidok.uni-freiburg.de:1632"},"canonical_url":"https://search.dev.ndltd.org/etd/freiburg-diss/oai:freidok.uni-freiburg.de:1632","repository":{"repo_id":"freiburg-diss","name":"University of Freiburg","base_url":"https://freidok.uni-freiburg.de/oai/oai2.php"},"display":{"title":"Mapping with mobile robots","abstract":"Today, mapping is largely considered the most difficult perceptual <br>problem in robotics. Different problems like the statistical <br>dependence, the correspondence problem, or dynamic elements makes <br>mapping so hard. The basic technique for mapping is incremental scan <br>matching. We present a method, which maximizes the likelihood of a <br>scan, given a motion model and the map built so far. This approach is <br>the constitutive techniques for further methods which addresses <br>special topics of the previous described problems. In this thesis we <br>describe following methods: <br> <br>We present a technique which combines a people tracker in the mapping <br>process to filter measurements caused by walking people. Additional <br>to the fact that maps contains less spurious objects, the accuracy of <br>the results can be increased. <br> <br>We present a second technique which is able to filter measurements <br>caused by dynamic objects. This time dynamic objects are not limited <br>to walking persons, every dynamic object can be filtered out if the <br>place of this object was seen as both: as free space as well as <br>occupied space. An EM-technique is used to optimize the mapping <br>results and in several practical experiments we will show that this <br>approach can effectively filter beams of different dynamic objects <br>like humans, cars etc. <br> <br>A famous problem in mapping is the so called closing loop problem. <br>When closing the cycle, the robot has to find out where it is relative <br>to its previously built map. This problem is complicated by the fact <br>that at the time of cycle closing, the robot's accumulated pose error <br>might be unboundedly large. We describe an efficient version of the <br>Rao-Blackwellized mapping approach. Using a Rao-Blackwellized <br>particle filter is a good techniques for estimating the posterior. In <br>combination with the scan matching technique we can decrease the <br>number of particles, so that it can be executed online. <br> <br>The Rao-Blackwellized mapping approach suffers from the inherent <br>problem of all particle filters: the particle depletion problem. We <br>present a new algorithm for data association in SLAM. In essence, our <br>approach searches the combinatorial tree of possible data association <br>decisions. The search is lazy: only when an alternative assignment <br>shows promise will it be evaluated. We tested our approach, and <br>consistently found that it produces accurate maps, even if for maps <br>with many large cycles. <br> <br>It can be difficult to distinguish places with data from range sensors <br>as measurements can look the same at different positions. RFID tags <br>have to nice property to be unique, they can report their <br>identification numbers which are easy to distinguish. Unfortunately <br>they don't provide any distance information, so that estimating the <br>location of the RFID tags is a difficult problem. We present an <br>approach to generate maps of RFID tags with mobile robots. We present <br>a sensor model that allows us to compute the likelihood of tag <br>detections given the relative position of the tag with respect to the <br>robot. Additionally we describe how to compute a posterior about the <br>position of a tag after the trajectory and the map is generated with a <br>highly accurate Rao-Blackwellized mapping algorithm for laser range <br>scans. <br> <br>We propose a technique for simultaneous scan registration and scan <br>deformation for modeling nonrigid objects. The deformation is made <br>possible through the definition of (soft) links between neighboring <br>scan points, whose configuration is calculated during registration. <br>To tackle the resulting optimization problem efficiently, we describe <br>a hierarchical optimization techniques that operate on thinned graphs. <br>Experimental results obtained using a mobile robot illustrate the <br>viability of this approach. <br> <br>Finally, we present two examples for complete systems which are able <br>to map their environment. The first system designed to autonomously <br>explore and acquire 3D maps of abandoned mines is a 1,500 pound <br>vehicle, nicknamed \"Groundhog\". The core of the Groundhog navigation <br>system is comprised of a software package that solves the SLAM problem <br>by acquiring 2D maps. Our research demonstrates that the autonomous <br>acquisition of maps of abandoned mines is indeed feasible with <br>autonomous robotic systems. The second system is an instrumented <br>helicopter platform for 3D ground modeling. A real-time algorithm is <br>developed that integrates pose estimates from multiple sensors with <br>range data, acquired by a 2D laser range finders oriented <br>perpendicular to the vehicle's flight direction. The algorithm uses a <br>fast optimization technique to generate maps in real-time.","abstract_html":"Today, mapping is largely considered the most difficult perceptual &lt;br&gt;problem in robotics. Different problems like the statistical &lt;br&gt;dependence, the correspondence problem, or dynamic elements makes &lt;br&gt;mapping so hard. The basic technique for mapping is incremental scan &lt;br&gt;matching. We present a method, which maximizes the likelihood of a &lt;br&gt;scan, given a motion model and the map built so far. This approach is &lt;br&gt;the constitutive techniques for further methods which addresses &lt;br&gt;special topics of the previous described problems. In this thesis we &lt;br&gt;describe following methods: &lt;br&gt; &lt;br&gt;We present a technique which combines a people tracker in the mapping &lt;br&gt;process to filter measurements caused by walking people. Additional &lt;br&gt;to the fact that maps contains less spurious objects, the accuracy of &lt;br&gt;the results can be increased. &lt;br&gt; &lt;br&gt;We present a second technique which is able to filter measurements &lt;br&gt;caused by dynamic objects. This time dynamic objects are not limited &lt;br&gt;to walking persons, every dynamic object can be filtered out if the &lt;br&gt;place of this object was seen as both: as free space as well as &lt;br&gt;occupied space. An EM-technique is used to optimize the mapping &lt;br&gt;results and in several practical experiments we will show that this &lt;br&gt;approach can effectively filter beams of different dynamic objects &lt;br&gt;like humans, cars etc. &lt;br&gt; &lt;br&gt;A famous problem in mapping is the so called closing loop problem. &lt;br&gt;When closing the cycle, the robot has to find out where it is relative &lt;br&gt;to its previously built map. This problem is complicated by the fact &lt;br&gt;that at the time of cycle closing, the robot&#x27;s accumulated pose error &lt;br&gt;might be unboundedly large. We describe an efficient version of the &lt;br&gt;Rao-Blackwellized mapping approach. Using a Rao-Blackwellized &lt;br&gt;particle filter is a good techniques for estimating the posterior. In &lt;br&gt;combination with the scan matching technique we can decrease the &lt;br&gt;number of particles, so that it can be executed online. &lt;br&gt; &lt;br&gt;The Rao-Blackwellized mapping approach suffers from the inherent &lt;br&gt;problem of all particle filters: the particle depletion problem. We &lt;br&gt;present a new algorithm for data association in SLAM. In essence, our &lt;br&gt;approach searches the combinatorial tree of possible data association &lt;br&gt;decisions. The search is lazy: only when an alternative assignment &lt;br&gt;shows promise will it be evaluated. We tested our approach, and &lt;br&gt;consistently found that it produces accurate maps, even if for maps &lt;br&gt;with many large cycles. &lt;br&gt; &lt;br&gt;It can be difficult to distinguish places with data from range sensors &lt;br&gt;as measurements can look the same at different positions. RFID tags &lt;br&gt;have to nice property to be unique, they can report their &lt;br&gt;identification numbers which are easy to distinguish. Unfortunately &lt;br&gt;they don&#x27;t provide any distance information, so that estimating the &lt;br&gt;location of the RFID tags is a difficult problem. We present an &lt;br&gt;approach to generate maps of RFID tags with mobile robots. We present &lt;br&gt;a sensor model that allows us to compute the likelihood of tag &lt;br&gt;detections given the relative position of the tag with respect to the &lt;br&gt;robot. Additionally we describe how to compute a posterior about the &lt;br&gt;position of a tag after the trajectory and the map is generated with a &lt;br&gt;highly accurate Rao-Blackwellized mapping algorithm for laser range &lt;br&gt;scans. &lt;br&gt; &lt;br&gt;We propose a technique for simultaneous scan registration and scan &lt;br&gt;deformation for modeling nonrigid objects. The deformation is made &lt;br&gt;possible through the definition of (soft) links between neighboring &lt;br&gt;scan points, whose configuration is calculated during registration. &lt;br&gt;To tackle the resulting optimization problem efficiently, we describe &lt;br&gt;a hierarchical optimization techniques that operate on thinned graphs. &lt;br&gt;Experimental results obtained using a mobile robot illustrate the &lt;br&gt;viability of this approach. &lt;br&gt; &lt;br&gt;Finally, we present two examples for complete systems which are able &lt;br&gt;to map their environment. The first system designed to autonomously &lt;br&gt;explore and acquire 3D maps of abandoned mines is a 1,500 pound &lt;br&gt;vehicle, nicknamed &quot;Groundhog&quot;. The core of the Groundhog navigation &lt;br&gt;system is comprised of a software package that solves the SLAM problem &lt;br&gt;by acquiring 2D maps. Our research demonstrates that the autonomous &lt;br&gt;acquisition of maps of abandoned mines is indeed feasible with &lt;br&gt;autonomous robotic systems. The second system is an instrumented &lt;br&gt;helicopter platform for 3D ground modeling. A real-time algorithm is &lt;br&gt;developed that integrates pose estimates from multiple sensors with &lt;br&gt;range data, acquired by a 2D laser range finders oriented &lt;br&gt;perpendicular to the vehicle&#x27;s flight direction. The algorithm uses a &lt;br&gt;fast optimization technique to generate maps in real-time.","abstract_has_math":false,"creators":["Hähnel, Dirk"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Burgard, Wolfram"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":null,"date_issued":"","date_published":null,"updated_at":"2026-07-24T02:22:22Z","subjects":["Mobile Roboter","Zustandsschätzung","Kartenbau","mobile robots","state estimation","map building"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://freidok.uni-freiburg.de/data/1632","outbound_label":"Repository record","outbound_source":"source_url"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Burgard, Wolfram"]},{"key":"dc:creator","label":"Author","values":["Hähnel, Dirk"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["DoctoralThesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Mobile Roboter","Zustandsschätzung","Kartenbau","mobile robots","state estimation","map building"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Today, mapping is largely considered the most difficult perceptual <br>problem in robotics. Different problems like the statistical <br>dependence, the correspondence problem, or dynamic elements makes <br>mapping so hard. The basic technique for mapping is incremental scan <br>matching. We present a method, which maximizes the likelihood of a <br>scan, given a motion model and the map built so far. This approach is <br>the constitutive techniques for further methods which addresses <br>special topics of the previous described problems. In this thesis we <br>describe following methods: <br> <br>We present a technique which combines a people tracker in the mapping <br>process to filter measurements caused by walking people. Additional <br>to the fact that maps contains less spurious objects, the accuracy of <br>the results can be increased. <br> <br>We present a second technique which is able to filter measurements <br>caused by dynamic objects. This time dynamic objects are not limited <br>to walking persons, every dynamic object can be filtered out if the <br>place of this object was seen as both: as free space as well as <br>occupied space. An EM-technique is used to optimize the mapping <br>results and in several practical experiments we will show that this <br>approach can effectively filter beams of different dynamic objects <br>like humans, cars etc. <br> <br>A famous problem in mapping is the so called closing loop problem. <br>When closing the cycle, the robot has to find out where it is relative <br>to its previously built map. This problem is complicated by the fact <br>that at the time of cycle closing, the robot's accumulated pose error <br>might be unboundedly large. We describe an efficient version of the <br>Rao-Blackwellized mapping approach. Using a Rao-Blackwellized <br>particle filter is a good techniques for estimating the posterior. In <br>combination with the scan matching technique we can decrease the <br>number of particles, so that it can be executed online. <br> <br>The Rao-Blackwellized mapping approach suffers from the inherent <br>problem of all particle filters: the particle depletion problem. We <br>present a new algorithm for data association in SLAM. In essence, our <br>approach searches the combinatorial tree of possible data association <br>decisions. The search is lazy: only when an alternative assignment <br>shows promise will it be evaluated. We tested our approach, and <br>consistently found that it produces accurate maps, even if for maps <br>with many large cycles. <br> <br>It can be difficult to distinguish places with data from range sensors <br>as measurements can look the same at different positions. RFID tags <br>have to nice property to be unique, they can report their <br>identification numbers which are easy to distinguish. Unfortunately <br>they don't provide any distance information, so that estimating the <br>location of the RFID tags is a difficult problem. We present an <br>approach to generate maps of RFID tags with mobile robots. We present <br>a sensor model that allows us to compute the likelihood of tag <br>detections given the relative position of the tag with respect to the <br>robot. Additionally we describe how to compute a posterior about the <br>position of a tag after the trajectory and the map is generated with a <br>highly accurate Rao-Blackwellized mapping algorithm for laser range <br>scans. <br> <br>We propose a technique for simultaneous scan registration and scan <br>deformation for modeling nonrigid objects. The deformation is made <br>possible through the definition of (soft) links between neighboring <br>scan points, whose configuration is calculated during registration. <br>To tackle the resulting optimization problem efficiently, we describe <br>a hierarchical optimization techniques that operate on thinned graphs. <br>Experimental results obtained using a mobile robot illustrate the <br>viability of this approach. <br> <br>Finally, we present two examples for complete systems which are able <br>to map their environment. The first system designed to autonomously <br>explore and acquire 3D maps of abandoned mines is a 1,500 pound <br>vehicle, nicknamed \"Groundhog\". The core of the Groundhog navigation <br>system is comprised of a software package that solves the SLAM problem <br>by acquiring 2D maps. Our research demonstrates that the autonomous <br>acquisition of maps of abandoned mines is indeed feasible with <br>autonomous robotic systems. The second system is an instrumented <br>helicopter platform for 3D ground modeling. A real-time algorithm is <br>developed that integrates pose estimates from multiple sensors with <br>range data, acquired by a 2D laser range finders oriented <br>perpendicular to the vehicle's flight direction. The algorithm uses a <br>fast optimization technique to generate maps in real-time.","Einer der entscheidenden Faktoren bei der Konstruktion eines <br>vollständig autonomen mobilen Roboters ist das Erstellen von Karten. <br>Diese Arbeit bietet Lösungsmöglichkeiten für unterschiedliche <br>Fragestellungen, die beim Kartenbau auftreten. Üblicherweise <br>beinhalten Karten nur die Beschreibungen von statischen Objekten in <br>der Umgebung, wie zum Beispiel Wände, Gebäude oder Straßen. <br>Dynamische Elemente, umhergehende Menschen oder ähnliches sind im <br>Allgemeinen nicht erwünscht. Ziel ist es daher, die Messungen, die <br>durch diese dynamischen Objekte verursacht werden, zu erkennen und zu <br>filtern. Neben der Reduzierung von unerwünschten Gegenständen in der <br>Karte kann dadurch auch die Genauigkeit der Karte erhöht werden. In <br>zahlreichen Experimenten wird demonstriert, dass die gefundenen <br>Methoden effektiv Messungen von diversen dynamischen Objekten, wie zum <br>Beispiel von Personen oder Autos detektieren und filtern können. Der <br>inkrementelle Vergleich von Abstandsbildern, das so genannte <br>\"Incremental Scan Matching\", ist ein elementarer Bestandteil vieler <br>hier gezeigter Ansätze. Diese Methode ermöglicht die Korrektur <br>lokaler Fehler und erlaubt die Erzeugung örtlich konsistenter Karten. <br>Kleinere Ungenauigkeiten in der Positionsbestimmung können sich <br>allerdings über die Zeit akkumulieren, und es kann daher leicht <br>passieren, dass eine globale Inkonsistenz eintritt, sobald ein vorher <br>gesehener Bereich wieder betreten wird. Eine weitere Schwierigkeit <br>beim Kartenbau ist demzufolge häufig das korrekte Schließen von <br>Zyklen. Hierbei muss der Roboter den akkumulierten Positionsfehler <br>erkennen und korrigieren, auch wenn dieser Fehler erheblich sein <br>sollte. Für diese Problematik werden zwei unterschiedliche Lösungen <br>vorgestellt. Die Erste basiert auf dem Einsatz von Rao-Blackwellized <br>Partikelfiltern, der allerdings die Notwendigkeit von erheblichen <br>Berechnungen impliziert. Es wird gezeigt, dass durch eine Kombination <br>mit dem vorgenannten Scan Matching, eine Realisierung in Echtzeit <br>möglich wird. Daneben wird ein Verfahren vorgestellt, das <br>Kartenabschnitte kombinatorisch verwaltet und Beziehungen zwischen den <br>Abschnitten nachträglich ändern kann, sofern ein Fehler erkannt wird. <br>In Experimenten wird gezeigt, dass mit Hilfe dieser Methoden Karten <br>von Umgebungen mit zahlreichen, auch verschachtelten, Schleifen <br>erstellt werden können. Neben des Problems der Erstellung von <br>geometrischen Karten werden in der vorliegenden Arbeit Techniken zur <br>Ermittlung von Position und Form einzelner Objekte vorgestellt. Zur <br>eindeutigen Identifizierung der Objekte werden in der Praxis <br>RFID-Systeme immer populärer. Die genaue Ortung der so genannten <br>RFID-Marken ist jedoch schwierig, da sie ihrerseits keine <br>Abstandsinformationen liefern und der Detektionsbereich der Antennen <br>mehrere Meter betragen kann. Es wird ein Verfahren gezeigt, das mit <br>Hilfe von mobilen Robotern detaillierte Karten dieser RFID-Marken <br>erstellt. Eine andere Technik ermöglicht es, aus Teilansichten eines <br>deformierbaren Objekts ein komplettes Modell zu generieren. Zur <br>Berechnung der Deformation werden die genauen Konfigurationen von <br>beweglichen Verbindungen zwischen benachbarten Messpunkten <br>herangezogen. Um das resultierende Optimierungsproblem zu <br>vereinfachen, wird eine hierarchische Darstellung benutzt. <br>Experimentelle Resultate zeigen die Realisierbarkeit des Ansatzes. <br>Schließlich werden, als Anwendungen der dargestellten Techniken, zwei <br>komplexe Systeme vorgestellt, die in der Lage sind, autonom ihre <br>Umgebung zu modellieren. Das erste System, das entwickelt wurde, um <br>dreidimensionale Karten von stillgelegten Minen zu erstellen, ist ein <br>800 kg schwerer Roboter mit dem Namen \"Groundhog\". Das <br>Basisnavigationssystem beinhaltet ein Softwarepaket, das das Problem <br>des Kartenbaus mittels zweidimensionaler Karten löst. Daneben wurde <br>ein mit unterschiedlichen Sensoren ausgestatteter Modellhelikopter <br>entwickelt, der eine dreidimensionale Karte eines Geländes erzeugen <br>kann. Ein zweidimensionales Lasermesssytem, das senkrecht zur <br>Flugrichtung orientiert ist, erlaubt es, in Echtzeit diese Karten zu <br>generieren."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Mapping with mobile robots","Kartenbau durch mobile Roboter"]}]}],"canonical_facts":{"dc:contributor":["Burgard, Wolfram"],"dc:creator":["Hähnel, Dirk"],"dc:description.abstract":["Today, mapping is largely considered the most difficult perceptual <br>problem in robotics. Different problems like the statistical <br>dependence, the correspondence problem, or dynamic elements makes <br>mapping so hard. The basic technique for mapping is incremental scan <br>matching. We present a method, which maximizes the likelihood of a <br>scan, given a motion model and the map built so far. This approach is <br>the constitutive techniques for further methods which addresses <br>special topics of the previous described problems. In this thesis we <br>describe following methods: <br> <br>We present a technique which combines a people tracker in the mapping <br>process to filter measurements caused by walking people. Additional <br>to the fact that maps contains less spurious objects, the accuracy of <br>the results can be increased. <br> <br>We present a second technique which is able to filter measurements <br>caused by dynamic objects. This time dynamic objects are not limited <br>to walking persons, every dynamic object can be filtered out if the <br>place of this object was seen as both: as free space as well as <br>occupied space. An EM-technique is used to optimize the mapping <br>results and in several practical experiments we will show that this <br>approach can effectively filter beams of different dynamic objects <br>like humans, cars etc. <br> <br>A famous problem in mapping is the so called closing loop problem. <br>When closing the cycle, the robot has to find out where it is relative <br>to its previously built map. This problem is complicated by the fact <br>that at the time of cycle closing, the robot's accumulated pose error <br>might be unboundedly large. We describe an efficient version of the <br>Rao-Blackwellized mapping approach. Using a Rao-Blackwellized <br>particle filter is a good techniques for estimating the posterior. In <br>combination with the scan matching technique we can decrease the <br>number of particles, so that it can be executed online. <br> <br>The Rao-Blackwellized mapping approach suffers from the inherent <br>problem of all particle filters: the particle depletion problem. We <br>present a new algorithm for data association in SLAM. In essence, our <br>approach searches the combinatorial tree of possible data association <br>decisions. The search is lazy: only when an alternative assignment <br>shows promise will it be evaluated. We tested our approach, and <br>consistently found that it produces accurate maps, even if for maps <br>with many large cycles. <br> <br>It can be difficult to distinguish places with data from range sensors <br>as measurements can look the same at different positions. RFID tags <br>have to nice property to be unique, they can report their <br>identification numbers which are easy to distinguish. Unfortunately <br>they don't provide any distance information, so that estimating the <br>location of the RFID tags is a difficult problem. We present an <br>approach to generate maps of RFID tags with mobile robots. We present <br>a sensor model that allows us to compute the likelihood of tag <br>detections given the relative position of the tag with respect to the <br>robot. Additionally we describe how to compute a posterior about the <br>position of a tag after the trajectory and the map is generated with a <br>highly accurate Rao-Blackwellized mapping algorithm for laser range <br>scans. <br> <br>We propose a technique for simultaneous scan registration and scan <br>deformation for modeling nonrigid objects. The deformation is made <br>possible through the definition of (soft) links between neighboring <br>scan points, whose configuration is calculated during registration. <br>To tackle the resulting optimization problem efficiently, we describe <br>a hierarchical optimization techniques that operate on thinned graphs. <br>Experimental results obtained using a mobile robot illustrate the <br>viability of this approach. <br> <br>Finally, we present two examples for complete systems which are able <br>to map their environment. The first system designed to autonomously <br>explore and acquire 3D maps of abandoned mines is a 1,500 pound <br>vehicle, nicknamed \"Groundhog\". The core of the Groundhog navigation <br>system is comprised of a software package that solves the SLAM problem <br>by acquiring 2D maps. Our research demonstrates that the autonomous <br>acquisition of maps of abandoned mines is indeed feasible with <br>autonomous robotic systems. The second system is an instrumented <br>helicopter platform for 3D ground modeling. A real-time algorithm is <br>developed that integrates pose estimates from multiple sensors with <br>range data, acquired by a 2D laser range finders oriented <br>perpendicular to the vehicle's flight direction. The algorithm uses a <br>fast optimization technique to generate maps in real-time.","Einer der entscheidenden Faktoren bei der Konstruktion eines <br>vollständig autonomen mobilen Roboters ist das Erstellen von Karten. <br>Diese Arbeit bietet Lösungsmöglichkeiten für unterschiedliche <br>Fragestellungen, die beim Kartenbau auftreten. Üblicherweise <br>beinhalten Karten nur die Beschreibungen von statischen Objekten in <br>der Umgebung, wie zum Beispiel Wände, Gebäude oder Straßen. <br>Dynamische Elemente, umhergehende Menschen oder ähnliches sind im <br>Allgemeinen nicht erwünscht. Ziel ist es daher, die Messungen, die <br>durch diese dynamischen Objekte verursacht werden, zu erkennen und zu <br>filtern. Neben der Reduzierung von unerwünschten Gegenständen in der <br>Karte kann dadurch auch die Genauigkeit der Karte erhöht werden. In <br>zahlreichen Experimenten wird demonstriert, dass die gefundenen <br>Methoden effektiv Messungen von diversen dynamischen Objekten, wie zum <br>Beispiel von Personen oder Autos detektieren und filtern können. Der <br>inkrementelle Vergleich von Abstandsbildern, das so genannte <br>\"Incremental Scan Matching\", ist ein elementarer Bestandteil vieler <br>hier gezeigter Ansätze. Diese Methode ermöglicht die Korrektur <br>lokaler Fehler und erlaubt die Erzeugung örtlich konsistenter Karten. <br>Kleinere Ungenauigkeiten in der Positionsbestimmung können sich <br>allerdings über die Zeit akkumulieren, und es kann daher leicht <br>passieren, dass eine globale Inkonsistenz eintritt, sobald ein vorher <br>gesehener Bereich wieder betreten wird. Eine weitere Schwierigkeit <br>beim Kartenbau ist demzufolge häufig das korrekte Schließen von <br>Zyklen. Hierbei muss der Roboter den akkumulierten Positionsfehler <br>erkennen und korrigieren, auch wenn dieser Fehler erheblich sein <br>sollte. Für diese Problematik werden zwei unterschiedliche Lösungen <br>vorgestellt. Die Erste basiert auf dem Einsatz von Rao-Blackwellized <br>Partikelfiltern, der allerdings die Notwendigkeit von erheblichen <br>Berechnungen impliziert. Es wird gezeigt, dass durch eine Kombination <br>mit dem vorgenannten Scan Matching, eine Realisierung in Echtzeit <br>möglich wird. Daneben wird ein Verfahren vorgestellt, das <br>Kartenabschnitte kombinatorisch verwaltet und Beziehungen zwischen den <br>Abschnitten nachträglich ändern kann, sofern ein Fehler erkannt wird. <br>In Experimenten wird gezeigt, dass mit Hilfe dieser Methoden Karten <br>von Umgebungen mit zahlreichen, auch verschachtelten, Schleifen <br>erstellt werden können. Neben des Problems der Erstellung von <br>geometrischen Karten werden in der vorliegenden Arbeit Techniken zur <br>Ermittlung von Position und Form einzelner Objekte vorgestellt. Zur <br>eindeutigen Identifizierung der Objekte werden in der Praxis <br>RFID-Systeme immer populärer. Die genaue Ortung der so genannten <br>RFID-Marken ist jedoch schwierig, da sie ihrerseits keine <br>Abstandsinformationen liefern und der Detektionsbereich der Antennen <br>mehrere Meter betragen kann. Es wird ein Verfahren gezeigt, das mit <br>Hilfe von mobilen Robotern detaillierte Karten dieser RFID-Marken <br>erstellt. Eine andere Technik ermöglicht es, aus Teilansichten eines <br>deformierbaren Objekts ein komplettes Modell zu generieren. Zur <br>Berechnung der Deformation werden die genauen Konfigurationen von <br>beweglichen Verbindungen zwischen benachbarten Messpunkten <br>herangezogen. Um das resultierende Optimierungsproblem zu <br>vereinfachen, wird eine hierarchische Darstellung benutzt. <br>Experimentelle Resultate zeigen die Realisierbarkeit des Ansatzes. <br>Schließlich werden, als Anwendungen der dargestellten Techniken, zwei <br>komplexe Systeme vorgestellt, die in der Lage sind, autonom ihre <br>Umgebung zu modellieren. Das erste System, das entwickelt wurde, um <br>dreidimensionale Karten von stillgelegten Minen zu erstellen, ist ein <br>800 kg schwerer Roboter mit dem Namen \"Groundhog\". Das <br>Basisnavigationssystem beinhaltet ein Softwarepaket, das das Problem <br>des Kartenbaus mittels zweidimensionaler Karten löst. Daneben wurde <br>ein mit unterschiedlichen Sensoren ausgestatteter Modellhelikopter <br>entwickelt, der eine dreidimensionale Karte eines Geländes erzeugen <br>kann. Ein zweidimensionales Lasermesssytem, das senkrecht zur <br>Flugrichtung orientiert ist, erlaubt es, in Echtzeit diese Karten zu <br>generieren."],"dc:format.medium":["application/pdf"],"dc:subject":["Mobile Roboter","Zustandsschätzung","Kartenbau","mobile robots","state estimation","map building"],"dc:title":["Mapping with mobile robots","Kartenbau durch mobile Roboter"],"dc:type":["DoctoralThesis"]},"updated_at":"2026-07-24T02:22:22Z"}