@inproceedings{Lin2021-PCTMA-NET, author = {Lin, Jianjie and Rickert, Markus and Perzylo, Alexander and Knoll, Alois}, title = {PCTMA-Net: Point Cloud Transformer with Morphing Atlas-based Point Generation Network for Dense Point Cloud Completion}, booktitle = {Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)}, year = {2021}, month = sep, address = {Prague, Czech Republic}, abstract = {Inferring a complete 3D geometry given an incomplete point cloud is essential in many vision and robotics applications. Previous work mainly relies on a global feature extracted by a Multi-layer Perceptron (MLP) for predicting the shape geometry. This suffers from a loss of structural details, as its point generator fails to capture the detailed topology and structure of point clouds using only the global features. The irregular nature of point clouds makes this task more challenging. This paper presents a novel method for shape completion to address this problem. The Transformer structure is currently a standard approach for natural language processing tasks and its inherent nature of permutation invariance makes it well suited for learning point clouds. Furthermore, the Transformer's attention mechanism can effectively capture the local context within a point cloud and efficiently exploit its incomplete local structure details. A morphing-atlas-based point generation network further fully utilizes the extracted point Transformer feature to predict the missing region using charts defined on the shape. Shape completion is achieved via the concatenation of all predicting charts on the surface. Extensive experiments on the Completion3D and KITTI data sets demonstrate that the proposed PCTMA-Net outperforms the state-of-the-art shape completion approaches and has a 10% relative improvement over the next best-performing method.}, keywords = {robotics}, } @incollection{Kessler2021, author = {Kessler, Ingmar and Perzylo, Alexander and Rickert, Markus}, editor = {Garoufallou, Emmanouel and Ovalle-Perandones, Maria-Antonia}, title = {Ontology-Based Decision Support System for the Nitrogen Fertilization of Winter Wheat}, booktitle = {Metadata and Semantics Research (MTSR 2020)}, publisher = {Springer International Publishing}, pages = {245--256}, year = {2021}, month = mar, address = {Cham}, abstract = {Digital technologies are already used in several aspects of agriculture. However, decision-making in crop production is still often a manual process that relies on various heterogeneous data sources. Small-scale farmers and their local consultants are particularly burdened by increasingly complex requirements. Regional circumstances and regulations play an essential role and need to be considered. This paper presents an ontology-based decision support system for the nitrogen fertilization of winter wheat in Bavaria, Germany. Semantic Web and Linked Data technologies were employed to both reuse and model new common semantic structures for interrelated knowledge. Many relevant general and regional data sources from multiple domains were not yet available in RDF. Hence, we used several tools to transform relevant data into corresponding OWL ontologies and combined them in a central knowledge base. The GUI application of the decision support system queries it to parameterize requests to external web services and to show relevant information in an integrated view. It further uses SPARQL queries to automatically generate recommendations for farmers and their consultants.}, isbn = {978-3-030-71903-6}, doi = {10.1007/978-3-030-71903-6_24}, keywords = {robotics, farmexpert}, } @article{Profanter2021, author = {Profanter, Stefan and Perzylo, Alexander and Rickert, Markus and Knoll, Alois}, title = {A Generic Plug \& Produce System Composed of Semantic OPC UA Skills}, journal = {IEEE Open Journal of the Industrial Electronics Society}, volume = {2}, pages = {128--141}, year = {2021}, month = jan, abstract = {Typical industrial workcells are composed of a plenitude of devices from various manufacturers, which rely on their own specific control interfaces. To reduce setup and reconfiguration times, a hardware-agnostic Plug & Produce system is required. In this paper, we present a system architecture that uses generic and semantically augmented OPC UA skills for robots, tools, and other system components. Standardized skill interfaces and parameters facilitate flexible component interchange and automatic parametrization with a focus on reusability of skills across different platforms and domains. The hierarchical composition of such skills allows for additional abstraction through the grouping of functionalities. Through the extension of OPC UA discovery services, available skills are dynamically detected whenever a manufacturing system's component is updated. The introduced Plug & Produce system is evaluated in multiple industrial workcells composed of robots, tool changer, electric parallel gripper, and vacuum gripper - all controlled via the proposed OPC UA skill interface. The evaluation of our system architecture demonstrates the applicability of the Plug & Produce concept in the domain of robot-based industrial assembly. Although it is necessary to adapt existing hardware to comply with the semantic skill concept, the initial one-time effort yields reoccurring efficiency gains during system reconfiguration. In particular, small lot production benefits from reduced changeover times.}, issn = {2644-1284}, doi = {10.1109/OJIES.2021.3055461}, } @inproceedings{Lin2020a, author = {Lin, Jianjie and Rickert, Markus and Knoll, Alois}, title = {{6D} Pose Estimation for Flexible Production with Small Lot Sizes based on {CAD} Models using {G}aussian Process Implicit Surfaces}, booktitle = {Proceedings of the {IEEE}/{RSJ} International Conference on Intelligent Robots and Systems ({IROS})}, year = {2020}, month = oct, address = {Las Vegas, NV, USA}, abstract = {We propose a surface-to-surface (S2S) point registration algorithm by exploiting the Gaussian Process Implicit Surfaces for partially overlapping 3D surfaces to estimate the 6D pose transformation. Unlike traditional approaches, that separate the corresponding search and update steps in the inner loop, we formulate the point registration as a nonlinear non-constraints optimization problem which does not explicitly use any corresponding points between two point sets. According to the implicit function theorem, we form one point set as a Gaussian Process Implicit Surfaces utilizing the signed distance function, which implicitly creates three manifolds. Points on the same manifold share the same function value, indicated as \{1, 0, -1\}. The problem is thus converted into finding a rigid transformation that minimizes the inherent function value. This can be solved by using a Gauss-Newton (GN) or Levenberg-Marquardt (LM) solver. In the case of a partially overlapping 3D surface, the Fast Point Feature Histogram (FPFH) algorithm is applied to both point sets and a Principal Component Analysis (PCA) is performed on the result. Based on this, the initial transformation can then be computed. We conduct experiments on multiple point sets to evaluate the effectiveness of our proposed approach against existing state-of-the-art methods.}, keywords = {robotics}, } @inproceedings{Perzylo2020a, author = {Perzylo, Alexander and Kessler, Ingmar and Profanter, Stefan and Rickert, Markus}, title = {Toward a Knowledge-Based Data Backbone for Seamless Digital Engineering in Smart Factories}, booktitle = {Proceedings of the IEEE International Conference on Emerging Technologies And Factory Automation (ETFA)}, pages = {164--171}, year = {2020}, month = sep, address = {Vienna, Austria}, abstract = {Digital transformation efforts in manufacturing companies bear the potential to reduce product costs and increase the flexibility of production systems. The semantic integration of data and information along the value chain enables the automated interpretation of interrelations between its different aspects such as product design, production process and manufacturing resources. These interrelations can be used to automatically generate semantic process descriptions and execute corresponding robot motions. An initial one-time effort to model the required knowledge of a particular application domain can make the manufacturing of high-variant products in small batches or even lot size one production more efficient. This paper introduces a knowledge-based digital engineering concept to automate engineering and production activities without human involvement. The concept was integrated and evaluated in a physical robot workcell where automotive fuse boxes are autonomously fitted with different fuse configurations.}, doi = {10.1109/ETFA46521.2020.9211943}, keywords = {robotics, data backbone}, url = {https://youtu.be/PtPd3YvTTzw}, } @article{Weckesser2020a, author = {Weckesser, Fabian and Peisl, Sebastian and Beck, Michael and Hartmann, Anja and R{\"{o}}hrl, Gerhard and Kessler, Ingmar and Perzylo, Alexander and Rickert, Markus}, title = {Daten vernetzen, unabh{\"{a}}ngig beraten}, journal = {Bayerisches Landwirtschaftliches Wochenblatt}, volume = {16}, year = {2020}, month = apr, abstract = {Mit einem Forschungsprojekt steigt das Landeskuratorium f{\"{u}}r pflanzliche Erzeugung in die digitale Beratung ein. FarmExpert 4.0 soll eine F{\"{u}}lle an Daten in einer Softwarearchitektur zum Nutzen der Landwirte vernetzen. Landwirte und Berater m{\"{u}}ssen bei pflanzenbaulichen Fragestellungen oft von Hand Fachwissen in Datenquellen nach-schlagen und miteinander kombinieren. Hinzu kommt, dass die gesetzlichen Rahmenbedingungen komplexer werden. Ein aktuelles Beispiel daf{\"{u}}r ist die D{\"{u}}ngeverordnung (D{\"{u}}V). Sonder- und Ausnahmeregelungen machen die Entscheidungsfindung f{\"{u}}r den Landwirt nicht einfacher. Der Betriebsleiter w{\"{u}}nscht sich Unterst{\"{u}}tzung beim Management seines Betriebes und bei der Erf{\"{u}}llung seiner Dokumentationspflichten. Es w{\"{a}}re viel gewonnen, wenn es hierf{\"{u}}r eine neutrale Softwarearchitektur g{\"{a}}be, die zu den Fragen des Landwirts die wichtigsten Informationen auf all seinen mobilen Endger{\"{a}}ten bereitstellt.}, keywords = {robotics,farmexpert}, url = {http://www.hswt.de/fileadmin/download/Forschung/Forschungsprojekte/1093_FarmExpert/WB_Daten_vernetzen_unabhaengig_beraten.pdf}, } @inproceedings{Wildgrube2019a, author = {Wildgrube, Fabian and Perzylo, Alexander and Rickert, Markus and Knoll, Alois}, title = {Semantic Mates: Intuitive Geometric Constraints for Efficient Assembly Specifications}, booktitle = {Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)}, pages = {6180--6187}, year = {2019}, month = nov, address = {Macao, China}, abstract = {In this paper, we enhance our knowledge-based and constraint-based approach of robot programming with the concept of Semantic Mates. They describe intended mechanical connections between parts of an assembly. This allows deriving appropriate assembly poses from the type of connection and the geometric properties of the involved parts. The paper presents an ontology-based representation of Semantic Mates that is used to augment object models with additional information regarding their potential use in an assembly. Such semantically annotated object models can be used in our instruction framework to program a robot to perform assembly tasks through simple drag-and-drop operations in a graphical user interface. We conducted a user study with 21 participants in order to evaluate the efficiency and usability of the Semantic Mates concept based on a use-case from the domain of mechanical assembly. Across different experience levels in robotics, the participants achieved a significantly faster workflow and improved perceived usability compared to the manual specification of constraint-based assembly operations.}, doi = {10.1109/IROS40897.2019.8968041}, keywords = {robotics, smecobot}, url = {https://youtu.be/o5EiAut3N2c}, } @inproceedings{Perzylo2019c, author = {Perzylo, Alexander and Profanter, Stefan and Rickert, Markus and Knoll, Alois}, title = {{OPC} {UA} NodeSet Ontologies as a Pillar of Representing Semantic Digital Twins of Manufacturing Resources}, booktitle = {Proceedings of the IEEE International Conference on Emerging Technologies And Factory Automation ({ETFA})}, pages = {1085--1092}, year = {2019}, month = sep, address = {Zaragoza, Spain}, abstract = {The effectiveness of cognitive manufacturing systems in agile production environments heavily depend on the automatic assessment of various levels of interoperability between manufacturing resources. For taking informed decisions, a semantically rich representation of all resources in a workcell or production line is required. OPC UA provides means for communication and information exchange in such distributed settings. This paper proposes a semantic representation of a resource's properties, in which we use OWL ontologies to encode the information models that can be found in OPC UA NodeSet specifications. We further combine these models with an OWL-based description of the resource's geometry and -- if applicable -- its kinematic model. This leads to a comprehensive semantic representation of hardware and software features of a manufacturing resource, which we call semantic digital twin. Among other things, it reduces costs through virtual prototyping and enables the automatic deployment of manufacturing tasks in production lines. As a result, small-batch assemblies become financially viable. In order to minimize the effort of creating OWL-based UA NodeSet descriptions, we provide a software tool for the automatic transformation of XML-based NodeSet specifications that adhere to the OPC Foundation's NodeSet2 XML schema.}, doi = {10.1109/ETFA.2019.8868954}, keywords = {robotics, data backbone, basys 4.0}, } @inproceedings{Profanter2019b, author = {Profanter, Stefan and Breitkreuz, Ari and Rickert, Markus and Knoll, Alois}, title = {A Hardware-Agnostic OPC UA Skill Model for Robot Manipulators and Tools}, booktitle = {Proceedings of the {IEEE} International Conference on Emerging Technologies And Factory Automation ({ETFA})}, year = {2019}, month = sep, address = {Zaragoza, Spain}, abstract = {The current trend to lot-size-one production requires reduced integration effort and easy reuse of available devices inside the production line. These devices have to offer a uniform interface to fulfill these requirements. This paper presents a hardware-agnostic skill model using the semantic modeling capabilities of OPC~UA. The model provides a standardized interface to hardware or software functionality while offering an intuitive way of grouping multiple skills to a higher hierarchical abstraction. Our skill model is based on OPC~UA Programs and modeled as an open source NodeSet. We hereby focus on the reusability of the skills for many different domains. The model is evaluated by controlling three different industrial robots and their tools through the same skill interface. The evaluation shows that our generic OPC~UA skill model can be used as a standardized control interface for device and software components in industrial manufacturing. With our solution new components can easily be exchanged without changing the interface. This is not only true for industrial robots, but for any device which provides a controllable functionality.}, keywords = {robotics, data backbone}, } @article{Perzylo2019a, author = {Perzylo, Alexander and Rickert, Markus and Kahl, Bj{\"{o}}rn and Somani, Nikhil and Lehmann, Christian and Kuss, Alexander and Profanter, Stefan and Billeso Beck, Anders and Haage, Mathias and Rath Hansen, Mikkel and Tofveson Nibe, Malene and Roa, M{\'{a}}ximo A. and S{\"{o}}rnmo, Olof and Gesteg{\aa}rd Robertz, Sven and Thomas, Ulrike and Veiga, Germano and Topp, Elin Anna and Kessler, Ingmar and Danzer, Marinus}, title = {{SME}robotics: Smart Robots for Flexible Manufacturing}, journal = {{IEEE} Robotics & Automation Magazine}, volume = {26}, number = {1}, pages = {78--90}, year = {2019}, month = mar, abstract = {Current market demands require an increasingly agile production environment throughout many manufacturing branches. Traditional automation systems and industrial robots, on the other hand, are often too inflexible to provide an economically viable business case for companies with rapidly changing products. The introduction of cognitive abilities into robotic and automation systems is, therefore, a necessary step toward lean changeover and seamless human–robot collaboration. In this article, we introduce the European Union (EU)-funded research project SMErobotics, which focuses on facilitating the use of robot systems in small and medium-sized enterprises (SMEs). We analyze open challenges for this target audience and develop multiple efficient technologies to address related issues. Real-world demonstrators of several end users and from multiple application domains show the impact these smart robots can have on SMEs. This article intends to give a broad overview of the research conducted in SMErobotics. Specific details of individual topics are provided through references to our previous publications.}, doi = {10.1109/MRA.2018.2879747}, keywords = {robotics, smerobotics}, } @incollection{Nafissi2019a, author = {Nafissi, Anahita and Weckesser, Fabian and Kessler, Ingmar and Rickert, Markus and Pfaff, Matthias and Peisl, Sebastian and Beck, Michael}, editor = {Meyer-Aurich, Andreas and Gandorfer, Markus and Barta, Norbert and Gronauer, Andreas and Kantelhardt, Jochen and Floto, Helga}, title = {{W}issensbasierte digitale {U}nterst{\"{u}}tzung in der {P}flanzenbauberatung}, booktitle = {Referate der 39. GIL-Jahrestagung in Wien: Informatik in der Land-, Forst- und Ern{\"{a}}hrungswirtschaft Fokus: Digitalisierung f{\"{u}}r landwirtschaftliche Betriebe in kleinstrukturierten Regionen -- ein Widerspruch in sich?}, publisher = {Gesellschaft f{\"{u}}r Informatik}, series = {Lecture Notes in Informatics}, volume = {287}, pages = {145--150}, year = {2019}, month = feb, address = {Bonn, Germany}, abstract = {Obwohl die Landwirtschaft schon immer technologische Neuerungen in der Produktion einsetzt, ist gerade die landwirtschaftliche Beratung bisher noch verh{\"{a}}ltnism{\"{a}}{\ss}ig wenig digitalisiert. Oft ist es g{\"{a}}ngige Praxis f{\"{u}}r Landwirte und Berater, gesetzliche Regelungen, Fachliteratur und Betriebsdaten in Papierform nachzuschlagen und in unstrukturierten, digitalen Dokumenten einzutragen. Zur Unterst{\"{u}}tzung der Landwirte und der Pflanzenbauberatung wird ein Entscheidungshilfesystem entwickelt, welches die Beratung in der Landwirtschaft digital unterst{\"{u}}tzen und erleichtern soll, indem es aktuelles Fach- und Expertenwissen sowie individuelle Betriebsdaten abruft, aufbereitet und zweckgebunden auswertet. Daf{\"{u}}r ist es notwendig, das entsprechende Fachwissen aus vielf{\"{a}}ltigen heterogenen Datenquellen in einer einheitlichen Wissensbasis verf{\"{u}}gbar zu machen. Der hier beschriebene Ansatz verwendet Semantic-Web-Technologien wie OWL-Ontologien und SPARQL-Abfragen, um diese Daten hinsichtlich ihrer Bedeutung, d.h. semantisch, zu modellieren und abzufragen.}, isbn = {9783885796817}, keywords = {farmexpert, robotics}, url = {https://www.gil-net.de/Publikationen/139_145.pdf}, } @inproceedings{Profanter2019a, author = {Profanter, Stefan and Tekat, Ayhun and Dorofeev, Kirill and Rickert, Markus and Knoll, Alois}, title = {OPC UA versus ROS, DDS, and MQTT: Performance Evaluation of Industry 4.0 Protocols}, booktitle = {Proceedings of the {IEEE} International Conference on Industrial Technology ({ICIT})}, year = {2019}, month = feb, address = {Melbourne, Australia}, abstract = {Ethernet-based protocols are getting more and more important for Industry 4.0 and the Internet of Things. In this paper, we compare the features, package overhead, and performance of some of the most important protocols in this area. First, we present a general feature comparison of OPC UA, ROS, DDS, and MQTT, followed by a more detailed wire protocol evaluation, which gives an overview over the protocol overhead for establishing a connection and sending data. In the performance tests we evaluate open-source implementations of these protocols by measuring the round trip time of messages in different system states: idle, high CPU load, and high network load. The performance analysis concludes with a test measuring the round trip time for 500 nodes on the same host.}, doi = {10.1109/ICIT.2019.8755050}, keywords = {robotics, smecobot}, } @inproceedings{Lin2018a, author = {Lin, Jianjie and Somani, Nikhil and Hu, Biao and Rickert, Markus and Knoll, Alois}, title = {An Efficient and Time-Optimal Trajectory Generation Approach for Waypoints under Kinematic Constraints and Error Bounds}, booktitle = {Proceedings of the {IEEE}/{RSJ} International Conference on Intelligent Robots and Systems ({IROS})}, year = {2018}, month = oct, address = {Madrid, Spain}, abstract = {This paper presents an approach to generate the time-optimal trajectory for a robot manipulator under certain kinematic constraints such as joint position, velocity, acceleration, and jerk limits. This problem of generating a trajectory that takes the minimum time to pass through specified waypoints is formulated as a nonlinear constraint optimization problem. Unlike prior approaches that model the motion of consecutive waypoints as a Cubic Spline, we model this motion with a seven-segment acceleration profile, as this trajectory results in a shorter overall motion time while staying within the bounds of the robot manipulator's constraints. The optimization bottleneck lies in the complexity that increases exponentially with the number of waypoints. To make the optimization scale well with the number of waypoints, we propose an approach that has linear complexity. This approach first divides all waypoints to consecutive batches, each with an overlap of two waypoints. The overlapping waypoints then act as a bridge to concatenate the optimization results of two consecutive batches. The whole trajectory is effectively optimized by successively optimizing every batch. We conduct experiments on practical scenarios and trajectories generated by motion planners to evaluate the effectiveness of our proposed approach over existing state-of-the-art approaches.}, doi = {10.1109/IROS.2018.8593577}, keywords = {robotics, trajectory generation}, } @incollection{Rickert2018a, author = {Rickert, Markus and Gaschler, Andre and Knoll, Alois}, editor = {Goswami, Ambarish and Vadakkepat, Prahlad}, title = {Applications in {HHI}: Physical Cooperation}, booktitle = {Humanoid Robotics: A Reference}, publisher = {Springer}, year = {2018}, month = oct, abstract = {Humans critically depend on permanent verbal and nonverbal interaction - for aligning their mental states, for synchronizing their intentions and goals, and also for performing joint tasks, such as carrying a heavy object together, manipulating of objects in a common workspace, or handing over components and building or assembling larger structures in teams. Typically, physical interaction is initiated by a short joint planning dialog and then further accompanied by a stream of verbal utterances. For obtaining a smooth interaction flow in a given situation, humans typically use all their communication modalities and senses, and this often happens even unconsciously. As we move toward the introduction of robotic co-workers that serve humans - some of them will be humanoids; others will be of a different shape - humans will expect them to be integrated into the execution of the task at hand, just as well as if a human co-worker was involved. Such a flawless replacement will only be possible if these robots provide a number of basic action primitives, for example, handover from human to robot and vice versa. The robots must also recognize and anticipate the intention of the human by analyzing and understanding the scene as far as necessary for jointly working on the task. Most importantly, the robotic co-worker must be able to carry on a verbal and nonverbal dialog with the human partner, in parallel with and relating to the physical interaction process. In this chapter, we give an overview of the ingredients of an integrated physical interaction scenario. This includes methods to plan activities, to produce safe and human-interpretable motion, to interact through multimodal communication, to schedule actions for a joint task, and to align and synchronize the interaction by understanding human intentions. We summarize the state of the art in physical human-humanoid interaction systems and conclude by presenting three humanoid systems as case studies.}, isbn = {9789400760455}, doi = {10.1007/978-94-007-6046-2_129}, keywords = {robotics, human-robot interaction, humanoid robotics}, url = {https://link.springer.com/content/pdf/10.1007%2F978-94-007-7194-9_129-1.pdf}, } @inproceedings{Cheng2018a, author = {Cheng, Chih-Hong and Diehl, Frederik and Hinz, Gereon Michael and Hamza, Yassine and N{\"{u}}hrenberg, Georg and Rickert, Markus and Rue{\ss}, Harald and Truong Le, Michael}, title = {Neural Networks for Safety-Critical Applications - {C}hallenges, Experiments and Perspectives}, booktitle = {Proceedings of the Design, Automation \& Test in Europe Conference \& Exhibition (DATE)}, pages = {1005--1006}, year = {2018}, month = mar, address = {Dresden, Germany}, abstract = {We propose a methodology for designing dependable Artificial Neural Networks (ANNs) by extending the concepts of understandability, correctness, and validity that are crucial ingredients in existing certification standards. We apply the concept in a concrete case study for designing a highway ANN-based motion predictor to guarantee safety properties such as impossibility for the ego vehicle to suggest moving to the right lane if there exists another vehicle on its right.}, doi = {10.23919/DATE.2018.8342158}, keywords = {autonomous driving, robotics, neural networks, safety}, } @inproceedings{Rickert2017a, author = {Rickert, Markus and Gaschler, Andre}, title = {{R}obotics {L}ibrary: An Object-Oriented Approach to Robot Applications}, booktitle = {Proceedings of the {IEEE}/{RSJ} International Conference on Intelligent Robots and Systems (IROS)}, year = {2017}, month = sep, address = {Vancouver, BC, Canada}, abstract = {We discuss the architecture and software engineering principles of the Robotics Library (RL). Driven by requirements of robot systems, research projects, industrial applications, and education, we identify relevant design requirements and present an approach to manage hardware and real-time, provide a user-friendly, object-oriented interface to powerful kinematics and dynamics calculations, and support various platforms. After over ten years of development that started in 2004 and evaluating many variants of the architecture, we discuss the design choices for the components of the library in its current version.}, doi = {10.1109/IROS.2017.8202232}, keywords = {robotics, robotics library}, url = {https://www.roboticslibrary.org/}, } @inproceedings{Kraft2017a, author = {Kraft, Martin and Rickert, Markus}, title = {How to Teach Your Robot in 5 Minutes: Applying {UX} Paradigms to Human-Robot-Interaction}, booktitle = {Proceedings of the {IEEE} International Symposium on Robot and Human Interactive Communication ({RO-MAN})}, year = {2017}, month = aug, address = {Lisbon, Portugal}, abstract = {When creating modern and visually appealing user experiences for the interaction with industrial robots, previously known and universally applicable paradigms in app and web design can be utilized to increase accessibility and usability of the to be created service. This is especially the case when the expected user group consists of untrained and inexperienced users and therefore system interaction focus is laid more on build progress overview, safety for human and robot, as well as overall simplification of complicated features. In this paper, we present four of the most important paradigms of modern graphical user experiences in web and app design that can be used to forward the concept of interacting with an industrial robot without any experience-related thresholds. By redesigning an existing interaction concept of a working robot cell system for assembly tasks in a small and medium-sized enterprise environment the presented paradigms are being utilized. The achieved improvements are then examined in a before-after user study to analyze the paradigm's success in suiting the user's expectation and anticipation using the redesigned service.}, doi = {10.1109/ROMAN.2017.8172416}, keywords = {robotics, smerobotics}, } @inproceedings{Chen2017a, author = {Chen, Chao and Rickert, Markus and Knoll, Alois}, title = {Motion Planning under Perception and Control Uncertainties with Space Exploration Guided Heuristic Search}, booktitle = {Proceedings of the {IEEE} Intelligent Vehicles Symposium}, year = {2017}, month = jun, address = {Redondo Beach, CA, USA}, abstract = {Reliability and safety are extremely important for autonomous driving in real traffic scenarios. However, due to imperfect control and sensing, the actual state of the vehicle cannot be flawlessly predicted or measured, but estimated with uncertainty. Therefor, it is important to consider the execution risk advance in motion planning for a solution with a high success rate. The Space Exploration Guided Heuristic Search (SEHS) method is extended to deal with perception and control uncertainty in its two planning stages. First, the localization uncertainty is evaluated with a simple probabilistic robot model by the Space Exploration to find a path corridor with sufficient localization quality for the desired motion accuracy. Then, a trajectory controller is modeled with nonholonomic kinematics for the belief propagation of a robot state with primitive motions. The dynamic model and the control feedback are approximated in a close neighborhood of the reference trajectory. In this case, the Heuristic Search can propagate the state uncertainty as a normal distribution in the search tree to guarantee a high probability of safety and to achieve the required final accuracy. The belief-based SEHS is evaluated in several simulated scenarios. Compared to the basic SEHS method that assumes perfection, motions with higher execution successful rate are produced, especially the human-like behaviors for driving through narrow passages and precise parking. This confirms the major contribution of this work in exploiting the uncertainties for motion planning in autonomous driving.}, doi = {10.1109/IVS.2017.7995801}, keywords = {robotics, autonomous driving, path planning}, } @article{Somani2017a, author = {Somani, Nikhil and Rickert, Markus and Knoll, Alois}, title = {An Exact Solver for Geometric Constraints with Inequalities}, journal = {{IEEE} Robotics and Automation Letters}, volume = {2}, number = {2}, pages = {1148--1155}, year = {2017}, month = apr, note = {Accepted for presentation at ICRA 2017}, abstract = {CAD/CAM approaches have been used in the manufacturing industry for a long time, and their use in robotic systems is becoming more popular. One common element in these approaches is the use of geometric constraints to define relative object poses. Hence, approaches for solving these geometric constraints are critical to their performance. In this work, we present an exact solver for geometric constraints. Our approach is based on mathematical models of constraints and geometric properties of constraint nullspaces. Our constraint solver supports non-linear constraints with inequalities, and also mixed transformation manifolds, i.e., cases where the rotation and translation components of the constraints are not independent. Through several applications, we show how inequality constraints and mixed transformation manifolds increase the expressive power of constraint-based task definitions. The exact solver provides repeatable solutions with deterministic runtimes and our experiments show that it is also much faster than comparable iterative solvers.}, doi = {10.1109/LRA.2017.2655113}, keywords = {robotics}, } @inproceedings{Perzylo2016a, author = {Perzylo, Alexander and Somani, Nikhil and Profanter, Stefan and Kessler, Ingmar and Rickert, Markus and Knoll, Alois}, title = {Intuitive Instruction of Industrial Robots: Semantic Process Descriptions for Small Lot Production}, booktitle = {Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)}, pages = {2293--2300}, year = {2016}, month = oct, address = {Daejeon, Republic of Korea}, abstract = {In this paper, we introduce a novel robot programming paradigm. It focuses on reducing the required expertise in robotics to a level that allows shop floor workers to use robots in their application domain without the need of extensive training. Our approach is user-centric and can interpret underspecified robot tasks, enabling communication on an abstract level. Such high-level task descriptions make the system amenable for users that are experts in a particular domain, but have limited knowledge about robotics and are thus not able to specify low-level details and instructions. Semantic models for all involved entities, i.e., processes, workpieces, and workcells, enable automatic reasoning about underspecified tasks and missing pieces of information. We showcase and evaluate this methodology on two industrial use cases from the domains of assembly and woodworking, comparing it to state-of-the-art solutions provided by robot manufacturers.}, doi = {10.1109/IROS.2016.7759358}, keywords = {robotics, smerobotics}, url = {https://youtu.be/bbInEMEF5zU}, } @inproceedings{Somani2016a, author = {Somani, Nikhil and Rickert, Markus and Gaschler, Andre and Cai, Caixia and Perzylo, Alexander and Knoll, Alois}, title = {Task Level Robot Programming using Prioritized Non-Linear Inequality Constraints}, booktitle = {Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)}, pages = {430--437}, year = {2016}, month = oct, address = {Daejeon, Republic of Korea}, abstract = {In this paper, we propose a framework for prioritized constraint-based specification of robot tasks. This framework is integrated with a cognitive robotic system based on semantic models of processes, objects, and workcells. The target is to enable intuitive (re-)programming of robot tasks, in a way that is suitable for non-expert users typically found in SMEs. Using CAD semantics, robot tasks are specified as geometric interrelational constraints. During execution, these are combined with constraints from the environment and the workcell, and solved in real-time. Our constraint model and solving approach supports a variety of constraint functions that can be non-linear and also include bounds in the form of inequalities, e.g., geometric interrelations, distance, collision avoidance and posture constraints. It is a hierarchical approach where priority levels can be specified for the constraints, and the nullspace of higher priority constraints is exploited to optimize the lower priority constraints. The presented approach has been applied to several typical industrial robotic use-cases to highlight its advantages compared to other state-of-the-art approaches.}, doi = {10.1109/IROS.2016.7759090}, keywords = {robotics}, url = {https://youtu.be/baet9IkTK04}, } @inproceedings{Chen2016a, author = {Chen, Chao and Rickert, Markus and Knoll, Alois}, title = {Combining Task and Motion Planning for Intersection Assistance Systems}, booktitle = {Proceedings of the {IEEE} Intelligent Vehicles Symposium}, pages = {1242--1247}, year = {2016}, month = jun, address = {Gothenburg, Sweden}, abstract = {A hybrid planning approach is developed for intersection assistance systems up to fully automated driving through intersections. Route planning, task planning and motion planning methods are integrated in a hierarchical planning framework to deal with the various information and constraints in different layers. The navigation agent provides a global driving direction at an intersection according to the selected route. The task planner decides a sequence of actions to accomplish the driving mission taking into consideration traffic rules and semantic conditions. The motion planner generates detailed trajectories to execute the tasks. Meanwhile, the task sequence and the motion trajectory are verified periodically against the actual traffic situation, and re-planning is triggered when necessary in the motion planning or task planning level. The hierarchical planning framework is evaluated in several intersection scenarios. The result shows that it can handle the complex planning problems with dynamic objects and provide a modular solution for automated driving that can be easily extended for different traffic rules and applications.}, doi = {10.1109/IVS.2016.7535549}, keywords = {autonomous driving}, } @article{Rickert2016a, author = {Rickert, Markus and Perzylo, Alexander}, title = {{I}ndustrieroboter f{\"{u}}r {KMU}: {F}lexible und intuitive {P}rozessbeschreibung}, journal = {{I}ndustrie {M}anagement}, volume = {32}, number = {2}, pages = {46--49}, year = {2016}, month = apr, abstract = {Die Produktion in kleinen und mittelst{\"{a}}ndischen Unternehmen (KMU) findet oft im Rahmen von Kleinserien oder sogar Einzelfertigung statt. Um diese KMU durch Roboter-basierte Automatisierung zu unterst{\"{u}}tzen, bedarf es eines Umdenkens in der Ausgestaltung der Bedienkonzepte. In diesen Anwendungsszenarien gewinnt die effiziente Programmierung und Adaption enorm an Stellenwert. Zudem muss das ben{\"{o}}tigte Vorwissen im Umgang mit Robotern soweit reduziert werden, dass Facharbeiter ohne gro{\ss}en Ausbildungsaufwand Robotersysteme selbst bedienen k{\"{o}}nnen. In diesem Beitrag stellen wir einen wissensbasierten Ansatz vor, der die genannten Herausforderungen behandelt.}, keywords = {robotics, smerobotics}, } @inproceedings{Somani2015c, author = {Somani, Nikhil and Perzylo, Alexander and Cai, Caixia and Rickert, Markus and Knoll, Alois}, title = {Object Detection Using Boundary Representations of Primitive Shapes}, booktitle = {Proceedings of the {IEEE} International Conference on Robotics and Biomimetics ({ROBIO})}, pages = {108--113}, year = {2015}, month = dec, address = {Zhuhai, China}, abstract = {In this paper, an approach for matching of primitive shapes detected from point clouds, to boundary representations of primitive shapes contained in CAD models of objects/workpieces is presented. The primary target application is object detection and pose estimation from noisy RGBD sensor data. This approach can also be used to determine incomplete object poses, including those of symmetrical objects. Detection and reasoning about these under-specified object poses is useful in several practical applications such as robotic manipulation, which are also presented in this paper.}, doi = {10.1109/ROBIO.2015.7414632}, keywords = {robotics, smerobotics}, } @inproceedings{Cai2015a, author = {Cai, Caixia and Somani, Nikhil and Rickert, Markus and Knoll, Alois}, title = {Prioritized Motion-Force Control of Multi-Constraints for Industrial Manipulators}, booktitle = {Proceedings of the IEEE International Conference on Robotics and Biomimetics (ROBIO)}, pages = {952--957}, year = {2015}, month = dec, address = {Zhuhai, China}, abstract = {To synthesize whole-body behaviors interactively, multiple tasks and constraints need to be simultaneously controlled, including those that guarantee that the constraints imposed by the robot's structure and the external environment are satisfied. In this paper, we present a prioritized, multiple-task control framework that is able to control forces in systems ranging from humanoids to industrial robots. Priorities between tasks are accomplished through null-space projection. Several relevant constraints (i.e., motion constraints, joint limits, force control) are tested to evaluate the control framework. Further, we evaluate the proposed approach in two typical industrial robotics applications: grasping of cylindrical objects and welding.}, doi = {10.1109/ROBIO.2015.7418894}, keywords = {robotics}, } @inproceedings{Roitberg2015a, author = {Roitberg, Alina and Somani, Nikhil and Perzylo, Alexander and Rickert, Markus and Knoll, Alois}, title = {Multimodal Human Activity Recognition for Industrial Manufacturing Processes in Robotic Workcells}, booktitle = {Proceedings of the {ACM} International Conference on Multimodal Interaction ({ICMI})}, pages = {259--266}, year = {2015}, month = nov, address = {Seattle, WA, USA}, abstract = {We present an approach for monitoring and interpreting human activities based on a novel multimodal vision-based interface, aiming at improving the efficiency of human-robot interaction (HRI) in industrial environments. Multi-modality is an important concept in this design, where we combine inputs from several state-of-the-art sensors to provide a variety of information, e.g. skeleton and fingertip poses. Based on typical industrial workflows, we derived multiple levels of human activity labels, including large-scale activities (e.g. assembly) and simpler sub-activities (e.g. hand gestures), creating a duration- and complexity-based hierarchy. We train supervised generative classifiers for each activity level and combine the output of this stage with a trained Hierarchical Hidden Markov Model (HHMM), which models not only the temporal aspects between the activities on the same level, but also the hierarchical relationships between the levels.}, doi = {10.1145/2818346.2820738}, keywords = {robotics, smerobotics}, } @inproceedings{Perzylo2015c, author = {Perzylo, Alexander and Somani, Nikhil and Profanter, Stefan and Gaschler, Andre and Griffiths, Sascha and Rickert, Markus and Knoll, Alois}, title = {Ubiquitous Semantics: Representing and Exploiting Knowledge, Geometry, and Language for Cognitive Robot Systems}, booktitle = {Proceedings of the Workshop Towards Intelligent Social Robots - Current Advances in Cognitive Robotics, {IEEE}/{RAS} International Conference on Humanoid Robots ({HUMANOIDS})}, year = {2015}, month = nov, address = {Seoul, South Korea}, abstract = {In this paper, we present an integrated approach to knowledge representation for cognitive robots. We combine knowledge about robot tasks, interaction objects including their geometric shapes, the environment, and natural language in a common ontological description. This description is based on the Web Ontology Language (OWL) and allows to automatically link and interpret these different kinds of information. Semantic descriptions are shared between object detection and pose estimation, task-level manipulation skills, and human-friendly interfaces. Through lifting the level of communication between the human operator and the robot system to an abstract level, we achieve more human-suitable interaction and thus a higher level of acceptance by the user. Furthermore, it increases the efficiency of communication. The benefits of our approach are highlighted by examples from the domains of industrial assembly and service robotics.}, keywords = {robotics, smerobotics}, } @inproceedings{Perzylo2015b, author = {Perzylo, Alexander and Somani, Nikhil and Rickert, Markus and Knoll, Alois}, title = {An Ontology for {CAD} Data and Geometric Constraints as a Link Between Product Models and Semantic Robot Task Descriptions}, booktitle = {Proceedings of the {IEEE}/{RSJ} International Conference on Intelligent Robots and Systems ({IROS})}, pages = {4197--4203}, year = {2015}, month = sep, address = {Hamburg, Germany}, abstract = {In this paper, we introduce an approach for leveraging CAD description to a semantic level, in order to link additional knowledge to CAD models and to exploit resulting synergy effects. This has been achieved by designing a description language, based on the Web Ontology Language (OWL), that is used to define boundary representations (BREP) of objects. This involves representing geometric entities in a semantic meaningful way, e.g., a circle is defined by a coordinate frame and a radius instead of a set of polygons. Furthermore, the scope of this semantic description language also covers geometric constraints between multiple objects. Constraints can be specified not only on the object level, but down to single edges or faces of an object. This semantic representation is used to improve a variety of applications, ranging from shape-based object recognition to constraint-based robot task descriptions. Results from a quantitative evaluation are presented to assess the practicability of this approach.}, doi = {10.1109/IROS.2015.7353971}, keywords = {robotics, smerobotics}, } @inproceedings{Profanter2015a, author = {Profanter, Stefan and Perzylo, Alexander and Somani, Nikhil and Rickert, Markus and Knoll, Alois}, title = {Analysis and Semantic Modeling of Modality Preferences in Industrial Human-Robot Interaction}, booktitle = {Proceedings of the {IEEE}/{RSJ} International Conference on Intelligent Robots and Systems ({IROS})}, pages = {1812--1818}, year = {2015}, month = sep, address = {Hamburg, Germany}, abstract = {Intuitive programming of industrial robots is especially important for small and medium-sized enterprises. We evaluated four different input modalities (touch, gesture, speech, 3D tracking device) regarding their preference, usability, and intuitiveness for robot programming. A Wizard-of-Oz experiment was conducted with 30 participants and its results show that most users prefer touch and gesture input over 3D tracking device input, whereas speech input was the least preferred input modality. The results also indicate that there are gender specific differences for preferred input modalities. We show how the results of the user study can be formalized in a semantic description language in such a way that a cognitive robotic workcell can benefit from the additional knowledge of input and output modalities, task parameter types, and preferred combinations of the two.}, doi = {10.1109/IROS.2015.7353613}, keywords = {robotics, smerobotics}, } @inproceedings{Somani2015b, author = {Somani, Nikhil and Gaschler, Andre and Rickert, Markus and Perzylo, Alexander and Knoll, Alois}, title = {Constraint-Based Task Programming with {CAD} Semantics: From Intuitive Specification to Real-Time Control}, booktitle = {Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)}, pages = {2854--2859}, year = {2015}, month = sep, address = {Hamburg, Germany}, abstract = {In this paper, we propose a framework for intuitive task-based programming of robots using geometric inter-relational constraints. The intended applications of this framework are robot programming interfaces that use semantically rich task descriptions, allow intuitive (re-)programming, and are suitable for non-expert users typically found in SMEs. A key concept in this work is the use of CAD semantics to represent geometric entities in the robotic workcell. The robot tasks are then represented as a set of geometrical inter-relational constraints, which are solved in real-time to be executed on the robot. Since these constraints often specify the target pose only partially, the robot can be controlled to move in the constraints' null space in order to handle external disturbances or further optimize the robot's pose during runtime. Geometrical inter-relational constraints are easy to understand and can be intuitively specified using CAD software. A number of applications common in industrial robotic scenarios have been chosen to highlight the advantages of the presented approach vis-{\`a}-vis the state-of-the-art approaches.}, doi = {10.1109/IROS.2015.7353770}, keywords = {robotics}, url = {https://youtu.be/qRJ1JmNoFEw}, } @inproceedings{Lenz2015a, author = {Lenz, David and Rickert, Markus and Knoll, Alois}, title = {Heuristic Search in Belief Space for Motion Planning under Map and Actuator Uncertainties}, booktitle = {Proceedings of the {IEEE}/{RSJ} International Conference on Intelligent Robots and Systems ({IROS})}, pages = {2659--2665}, year = {2015}, month = sep, address = {Hamburg, Germany}, abstract = {In order to fully exploit the capabilities of a robotic system, it is necessary to consider the limitations and errors of actuators and sensors already during the motion planning phase. In this paper, a framework for path planning is introduced, that uses heuristic search to build up a search graph in belief space, an extension to the deterministic state space considering the uncertainty associated with this space. As sources of uncertainty, actuator errors and map uncertainties are considered. We apply this framework to various scenarios for a non-holonomic vehicle and compare the resulting paths to heuristic state space planners and LQG-MP with the help of simulations. As a result, paths generated with this framework could either not be found with worst-case assumptions or have a higher probability of being successfully executed compared to planners with more relaxed constraints.}, doi = {10.1109/IROS.2015.7353740}, keywords = {autonomous driving, robotics}, } @inproceedings{Chen2015c, author = {Chen, Chao and Rickert, Markus and Knoll, Alois}, title = {Kinodynamic Motion Planning with Space-Time Exploration Guided Heuristic Search for Car-Like Robots in Dynamic Environments}, booktitle = {Proceedings of the {IEEE}/{RSJ} International Conference on Intelligent Robots and Systems ({IROS})}, pages = {2666--2671}, year = {2015}, month = sep, address = {Hamburg, Germany}, abstract = {The Space Exploration Guided Heuristic Search (SEHS) method solves the motion planning problem, especially for car-like robots, in two steps: a circle-based space exploration in the workspace followed by a circle-guided heuristic search in the configuration space. This paper extends this approach for kinodynamic planning in dynamic environments by performing the exploration in both space and time domains. Thus, a time-dependent heuristic is constructed to guide the search algorithm applying a kinodynamic vehicle model. Furthermore, the search step-size and state resolution are adapted incrementally to guarantee resolution completeness with a trade-off for efficiency. The performance of Space-Time Exploration Guided Heuristic Search (STEHS) approach is verified in two scenarios and compared with several search-based and sampling-based methods.}, doi = {10.1109/IROS.2015.7353741}, keywords = {autonomous driving, robotics}, url = {https://www.youtube.com/watch?v=AmyweePd1HU}, } @inproceedings{Somani2015a, author = {Perzylo, Alexander and Somani, Nikhil and Profanter, Stefan and Rickert, Markus and Knoll, Alois}, title = {Multimodal Binding of Parameters for Task-Based Robot Programming Based on Semantic Descriptions of Modalities and Parameter Types}, booktitle = {Proceedings of the Workshop on Multimodal Semantics for Robotic Systems, {IEEE}/{RSJ} International Conference on Intelligent Robots and Systems ({IROS})}, year = {2015}, month = sep, address = {Hamburg, Germany}, abstract = {In this paper, we describe our ongoing efforts to design a cognition-enabled industrial robotic workcell, which significantly increases the efficiency of teaching and adapting robot tasks. We have designed a formalism to match task parameter and input modality types, in order to infer suitable means for binding values to those parameters. All modalities are integrated through a graphical user interface, which a human operator can use to program industrial robots in an intuitive way by arbitrarily choosing modalities according to his or her preference.}, keywords = {robotics, smerobotics}, } @inproceedings{Chen2015a, author = {Chen, Chao and Rickert, Markus and Knoll, Alois}, title = {Path Planning with Orientation-Aware Space Exploration Guided Heuristic Search for Autonomous Parking and Maneuvering}, booktitle = {Proceedings of the {IEEE} Intelligent Vehicles Symposium ({IV})}, pages = {1148--1153}, year = {2015}, month = jul, address = {Seoul, South Korea}, abstract = {Due to the nonholonomic constraints of the vehicle kinematics, parking and maneuvering a car in a narrow clustered space are among the most challenging driving tasks. This paper introduces an extended version of Space Exploration Guided Heuristic Search (SEHS) method, called Orientation-Aware Space Exploration Guided Heuristic Search (OSEHS), to solve the path planning problems for parking and maneuvering. This method considers the orientation of a vehicle in the space exploration phase to achieve knowledge about driving directions. Such information is exploited later in the heuristic search phase to improve the planning efficiency in maneuvering scenarios. This approach is not bound to the specific domain knowledge about a parking or maneuvering task, but obtains the space dimension and orientation information through a generic exploration procedure. Therefore, it is convenient to integrate the maneuvering ability into a general SEHS motion planning framework. Experiments show that the OSEHS approach produces better results than common random-sampling methods and general heuristic search methods.}, doi = {10.1109/IVS.2015.7225838}, keywords = {autonomous driving, robotics}, } @inproceedings{ChenChao2015b, author = {Chen, Chao and Gaschler, Andre and Rickert, Markus and Knoll, Alois}, title = {Task Planning for Highly Automated Driving}, booktitle = {Proceedings of the {IEEE} Intelligent Vehicles Symposium ({IV})}, pages = {940--945}, year = {2015}, month = jul, address = {Seoul, South Korea}, abstract = {A hybrid planning approach is presented in this paper with the focus of integrating task planning and motion planning for highly automated driving. In the context of task planning, the vehicle and environment states are transformed from the continuous configuration space to a discrete state space. A planning problem is solved by a search algorithm for an optimal task sequence to reach the goal conditions in the symbolic space, regarding constraints such as space topology, place occupation, and traffic rules. Each task can be mapped to a specific driving maneuver and solved with a dedicated motion planning method in the continuous configuration space. The task planning approach not only bridges the gap between high-level navigation and low-level motion planning, but also provides a modular domain description that can be developed and verified individually. Our task planner for automated driving is evaluated in several scenarios with prior knowledge about the road-map and sensing range of the vehicle. Behavior that is otherwise complex to achieve is planned according to traffic rules and re-planned regarding the on-line perception.}, doi = {10.1109/IVS.2015.7225805}, keywords = {autonomous driving, robotics}, } @inproceedings{Perzylo2015a, author = {Perzylo, Alexander and Somani, Nikhil and Profanter, Stefan and Rickert, Markus and Knoll, Alois}, title = {Toward Efficient Robot Teach-In and Semantic Process Descriptions for Small Lot Sizes}, booktitle = {Proceedings of the Workshop on Combining AI Reasoning and Cognitive Science with Robotics, Robotics: Science and Systems ({RSS})}, year = {2015}, month = jul, address = {Rome, Italy}, abstract = {We present a novel robot programming methodology that is aimed at reducing the level of robotics expert knowledge needed to operate industrial robotic systems by explicitly modeling this knowledge and abstracting it from the user. Most of the current robot programming paradigms are either user-centric and fully-specify the robot's task to the lowest detail (used mostly in large industrial robotic systems) or fully autonomous solutions that generate the tasks from a problem description (used often in service and personal robotics). We present an approach that is user-centric and can interpret underspecified robot tasks. Such task descriptions make the system amenable for users that are experts in a particular domain, but have limited knowledge about robotics and are thus not able to specify low-level details and instructions. Semantic models for all involved entities enable automatic reasoning about underspecified tasks and missing pieces of information. We demonstrate this approach on an industrial assembly use-case and present a preliminary evaluation---both qualitatively and quantitatively---vis-{\`{a}}-vis state-of-the-art solutions available from industrial robot manufacturers.}, keywords = {robotics, smerobotics}, url = {http://youtu.be/B1Qu8Mt3WtQ}, } @article{Rickert2014a, author = {Rickert, Markus and Sieverling, Arne and Brock, Oliver}, title = {Balancing Exploration and Exploitation in Sampling-Based Motion Planning}, journal = {{IEEE} Transactions on Robotics}, volume = {30}, number = {6}, pages = {1305--1317}, year = {2014}, month = dec, abstract = {We present the exploring/exploiting tree (EET) algorithm for motion planning. The EET planner deliberately trades probabilistic completeness for computational efficiency. This tradeoff enables the EET planner to outperform state-of-the-art sampling-based planners by up to three orders of magnitude. We show that these considerable speedups apply for a variety of challenging real-world motion planning problems. The performance improvements are achieved by leveraging work space information to continuously adjust the sampling behavior of the planner. When the available information captures the planning problem's inherent structure, the planner's sampler becomes increasingly exploitative. When the available information is less accurate, the planner automatically compensates by increasing local configuration space exploration. We show that active balancing of exploration and exploitation based on workspace information can be a key ingredient to enabling highly efficient motion planning in practical scenarios.}, doi = {10.1109/TRO.2014.2340191}, keywords = {robotics, motion planning, path planning, robotics library}, } @inproceedings{Roitberg2014, author = {Roitberg, Alina and Perzylo, Alexander and Somani, Nikhil and Giuliani, Manuel and Rickert, Markus and Knoll, Alois}, title = {Human Activity Recognition in the Context of Industrial Human-Robot Interaction}, booktitle = {Proceedings of the AsiaPacific Signal and Information Processing Association Annual Summit and Conference (APSIPA ASC)}, pages = {1--10}, year = {2014}, month = dec, address = {Siem Reap, Cambodia}, abstract = {Human activity recognition is crucial for intuitive cooperation between humans and robots. We present an approach for activity recognition for applications in the context of human-robot interaction in industrial settings. The approach is based on spatial and temporal features derived from skeletal data of human workers performing assembly tasks. These features were used to train a machine learning framework, which classifies discrete time frames with Random Forests and subsequently models temporal dependencies between the resulting states with a Hidden Markov Model. We considered the following three groups of activities: Movement, Gestures, and Object handling. A dataset has been collected which is comprised of 24 recordings of several human workers performing such activities in a human-robot interaction environment, as typically seen at small and medium-sized enterprises. The evaluation shows that the approach achieves a recognition accuracy of up to 88% for some activities and an average accuracy of 73%.}, doi = {10.1109/APSIPA.2014.7041588}, keywords = {robotics, james, smerobotics}, } @inproceedings{Somani2014a, author = {Somani, Nikhil and Cai, Caixia and Perzylo, Alexander and Rickert, Markus and Knoll, Alois}, title = {Object Recognition Using Constraints from Primitive Shape Matching}, booktitle = {Proceedings of the 10th International Symposium on Visual Computing (ISVC'14)}, publisher = {Springer}, pages = {783--792}, year = {2014}, month = dec, address = {Las Vegas, NV, USA}, abstract = {In this paper, an object recognition and pose estimation approach based on constraints from primitive shape matching is presented. Additionally, an approach for primitive shape detection from point clouds using an energy minimization formulation is presented. Each primitive shape in an object adds geometric constraints on the object's pose. An algorithm is proposed to find minimal sets of primitive shapes which are sufficient to determine the complete 3D position and orientation of a rigid object. The pose is estimated using a linear least squares solver over the combination of constraints enforced by the primitive shapes. Experiments illustrating the primitive shape decomposition of object models, detection of these minimal sets, feature vector calculation for sets of shapes and object pose estimation have been presented on simulated and real data.}, doi = {10.1007/978-3-319-14249-4_75}, keywords = {robotics, smerobotics}, } @inproceedings{Chen2014a, author = {Chen, Chao and Rickert, Markus and Knoll, Alois}, title = {A Traffic Knowledge Aided Vehicle Motion Planning Engine Based on Space Exploration Guided Heuristic Search}, booktitle = {Proceedings of the IEEE Intelligent Vehicles Symposium}, pages = {535--540}, year = {2014}, month = jun, address = {Dearborn, MI, USA}, location = {Dearborn, Michigan, USA}, abstract = {A real-time vehicle motion planning engine is presented in this paper, with the focus on exploiting the prior and online traffic knowledge, e.g., predefined roadmap, prior environment information, behaviour-based motion primitives, within the space exploration guided heuristic search (SEHS) framework. The SEHS algorithm plans a kinodynamic vehicle motion in two steps: a geometric investigation of the free space, followed by a grid-free heuristic search employing primitive motions. These two procedures are generic and possible to take advantage of traffic knowledge. In this paper, the space exploration is supported by a roadmap and the heuristic search benefits from the behaviour-based primitives. Based on this idea, a light weighted motion planning engine is built, with the purpose to handle the traffic knowledge and the planning time in real-time motion planning. The experiments demonstrate that this SEHS motion planning engine is flexible and scalable for practical traffic scenarios with better results than the baseline SEHS motion planner regarding the provided traffic knowledge.}, doi = {10.1109/IVS.2014.6856458}, keywords = {autonomous driving, robotics}, } @inproceedings{Gaschler2014b, author = {Gaschler, Andre and Springer, Maximilian and Rickert, Markus and Knoll, Alois}, title = {Intuitive Robot Tasks with Augmented Reality and Virtual Obstacles}, booktitle = {Proceedings of the {IEEE} International Conference on Robotics and Automation ({ICRA})}, pages = {6026--6031}, year = {2014}, month = jun, address = {Hong Kong, China}, abstract = {Today's industrial robots require expert knowledge and are not profitable for small and medium sized enterprises with their small lot sizes. It is our strong belief that more intuitive robot programming in an augmented reality robot work cell can dramatically simplify re-programming and leverage robotics technology in short production cycles. In this paper, we present a novel augmented reality system for defining virtual obstacles, specifying tool positions, and specifying robot tasks. We evaluate the system in a user study and, more specifically, investigate the input of robot end-effector orientations in general.}, doi = {10.1109/ICRA.2014.6907747}, keywords = {robotics, james, smerobotics}, } @inproceedings{Gaschler2013c, author = {Gaschler, Andre and Petrick, Ronald P. A. and Giuliani, Manuel and Rickert, Markus and Knoll, Alois}, title = {{KVP}: A Knowledge of Volumes Approach to Robot Task Planning}, booktitle = {Proceedings of the {IEEE}/{RSJ} International Conference on Intelligent Robots and Systems ({IROS})}, pages = {202--208}, year = {2013}, month = nov, address = {Tokyo, Japan}, abstract = {Robot task planning is an inherently challenging problem, as it covers both continuous-space geometric reasoning about robot motion and perception, as well as purely symbolic knowledge about actions and objects. This paper presents a novel "knowledge of volumes" framework for solving generic robot tasks in partially known environments. In particular, this approach (abbreviated, KVP) combines the power of symbolic, knowledge-level AI planning with the efficient computation of volumes, which serve as an intermediate representation for both robot action and perception. While we demonstrate the effectiveness of our framework in a bimanual robot bartender scenario, our approach is also more generally applicable to tasks in automation and mobile manipulation, involving arbitrary numbers of manipulators.}, doi = {10.1109/IROS.2013.6696354}, keywords = {robotics, james}, } @inproceedings{Chen2013a, author = {Chen, Chao and Rickert, Markus and Knoll, Alois}, title = {Combining Space Exploration and Heuristic Search in Online Motion Planning for Nonholonomic Vehicles}, booktitle = {Proceedings of the IEEE Intelligent Vehicles Symposium}, pages = {1307--1312}, year = {2013}, month = jun, address = {Gold Coast, Australia}, abstract = {This paper presents an efficient motion planning method for nonholonomic vehicles, which combines space exploration and heuristic search to achieve online performance. The space exploration employs simple geometric shapes to investigate the collision-free space for the dimension and topology information. Then, the heuristic search is guided by this knowledge to generate vehicle motions under kinodynamic constraints. The overall performance of this framework greatly benefits from the cooperation of these two simple generic algorithms in suitable domains, which sequentially handles the free-space information and kinodynamic constraints. Experimental results show that this method is able to generate motions for nonholonomic vehicles in a time frame of less than 100 milliseconds for the given problem settings. The contribution of this work is the development of a Space Exploration Guided Heuristic Search with a circle-path based heuristics and adaptable search step size. The approach is grid-free and able to plan nonholonomic vehicle motions under kinodynamic constraints.}, doi = {10.1109/IVS.2013.6629647}, keywords = {autonomous driving, robotics, path planning, motion planning}, } @article{Kupferberg2011a, author = {Kupferberg, Aleksandra and Glasauer, Stefan and Huber, Markus and Rickert, Markus and Knoll, Alois and Brandt, Thomas}, title = {Biological Movement Increases Acceptance of Humanoid Robots as Human Partners in Motor Interaction}, journal = {{AI} \& Society}, volume = {26}, number = {4}, pages = {339--345}, year = {2011}, month = nov, abstract = {The automatic tendency to anthropomorphize our interaction partners and make use of experience acquired in earlier interaction scenarios leads to the suggestion that social interaction with humanoid robots is more pleasant and intuitive than that with industrial robots. An objective method applied to evaluate the quality of human–robot interaction is based on the phenomenon of motor interference (MI). It claims that a face-to-face observation of a different (incongruent) movement of another individual leads to a higher variance in one’s own movement trajectory. In social interaction, MI is a consequence of the tendency to imitate the movement of other individuals and goes along with mutual rapport, sense of togetherness, and sympathy. Although MI occurs while observing a human agent, it disappears in case of an industrial robot moving with piecewise constant velocity. Using a robot with human-like appearance, a recent study revealed that its movements led to MI, only if they were based on human prerecording (biological velocity), but not on constant (artificial) velocity profile. However, it remained unclear, which aspects of the human prerecorded movement triggered MI: biological velocity profile or variability in movement trajectory. To investigate this issue, we applied a quasi-biological minimum-jerk velocity profile (excluding variability in the movement trajectory as an influencing factor of MI) to motion of a humanoid robot, which was observed by subjects performing congruent or incongruent arm movements. The increase in variability in subjects’ movements occurred both for the observation of a human agent and for the robot performing incongruent movements, suggesting that an artificial human-like movement velocity profile is sufficient to facilitate the perception of humanoid robots as interaction partners.}, doi = {10.1007/s00146-010-0314-2}, keywords = {robotics}, } @inproceedings{Wittmeier2011a, author = {Wittmeier, Steffen and J{\"{a}}ntsch, Michael and Dalamagkidis, Konstantinos and Rickert, Markus and Marques, Hugo Gravato and Knoll, Alois}, title = {Caliper: A Universal Robot Simulation Framework for Tendon-Driven Robots}, booktitle = {Proceedings of the {IEEE}/{RSJ} International Conference on Intelligent Robots and Systems}, pages = {1063--1068}, year = {2011}, month = sep, address = {San Francisco, CA, USA}, abstract = {The development of increasingly complex robots in recent years has been characterized by an extensive use of physics-based simulations for controller design and optimization. Today, a variety of open-source and commercial simulators exist for this purpose for mobile and industrial robots. However, existing simulation engines still lack support for the emerging class of tendon-driven robots. In this paper, an innovative simulation framework for the simulation of tendon-driven robots is presented. It consists of a generic physics simulator capable of utilizing CAD robot models and a set of additional tools for simulation control, data acquisition and system investigation. The framework software architecture has been designed using component-based development principles to facilitate the framework extension and customization. Furthermore, for inter-component communication, the operating-system and programming language independent Common Object Request Broker Architecture (CORBA) has been used which simplifies the integration of the framework into existing software environments.}, doi = {10.1109/IROS.2011.6094455}, keywords = {robotics, eccerobot}, } @inproceedings{Lenz2011a, author = {Lenz, Claus and R{\"{o}}der, Thorsten and Rickert, Markus and Knoll, Alois}, editor = {Elmoataz, Abderrahim and Lezoray, Olivier and Nouboud, Fathallah and Mammass, Driss}, title = {Distance-Weighted {K}alman Fusion for Precise Docking Problems}, booktitle = {Proceedings of the International Conference on Mobile Robots and Competitions}, year = {2011}, month = apr, address = {Lisbon, Portugal}, abstract = {This paper proposes a way to solve a highly precise docking problem for a flexible delivery in production environments. The docking problem is seen as one of the fundamental problems to enable more flexible automation using mobile robots. A non-holonomic differential-driven robot with two conveyor belts is used to deliver boxes with goods to two docking slots on an assembly belt and unload them precisely. In order to localize the robot in front of the docking slots, a safety LIDAR and two "minimal invasive" reflecting markers are used that are completely light invariant, thus reaching industrial robustness. This measurement is fused with odometry using a Kalman filter and a distance weighted way to compute the reliability of the data streams.}, keywords = {robotics}, } @inproceedings{DBLP:conf/compsac/ChengRBLK09, author = {Cheng, Chih-Hong and Rickert, Markus and Buckl, Christian and Lee, Edward A. and Knoll, Alois}, title = {Toward the Design of Robotic Software with Verifiable Safety}, booktitle = {Proceedings of the 33rd Annual {IEEE} International Computer Software and Applications Conference, {COMPSAC} 2009, Seattle, Washington, USA, July 20-24, 2009. Volume 1}, pages = {622--623}, year = {2009}, doi = {10.1109/COMPSAC.2009.89}, url = {http://dx.doi.org/10.1109/COMPSAC.2009.89}, crossref = {DBLP:conf/compsac/2009}, }