Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Enabling Human-Robot-Interaction via Virtual and Augmented Reality in Distributed Control Systems
    ( 2018)
    Guhl, Jan
    ;
    Hügle, Johannes
    ;
    Krüger, Jörg
    Production and assembly lines are nowadays transforming into flexible and interconnected cells due to rapidly changing production demands. Changes are, for example, varying locations and poses for the processed work pieces and tools as well as the involved machinery like industrial robots. Even a variation in the combination or sequence of different production steps is possible. In case of older involved machines the task of reconfiguration and calibration can be time consuming. This may lead, in addition with the expected upcoming shortage of highly skilled workers, to future challenges, especially for small and medium sized enterprises. One possibility to address these challenges is to use distributed or cloud-based control for the participating machines. These approaches allow the use of more sophisticated and therefore in most cases computationally heavier algorithms than offered by classic monolithic controls. Those algorithms range from simple visual servoing applications to more complex scenarios, like sampling-based path planning in a previously 3D-reconstructed robot cell. Moving the computation of the machine's reactions physically and logically away from the machine control complicates the supervision and verification of the computed robot paths and trajectories. This poses a potential threat to the machine's operator since he/she is hardly capable of predicting or controlling the robot's movements. To overcome this drawback, this paper presents a system which allows the user to interact with industrial robot and other cyber physical systems via augmented and virtual reality. Captured topics in this paper are the architecture and concept for the distributed system, first implementation details and promising results obtained by using a Microsoft HoloLens and other visualization devices.
  • Publication
    Affordance Based Approach to Automatic Program Generation for Industrial Robots in Manufacturing
    ( 2018)
    Heimann, Oliver
    ;
    Krüger, Jörg
    Due to the increasing demand for flexible and low-cost production, manufacturing solutions involving human robot interaction have become much sought-after. Robotic manufacturers meet the demand with a rising number of low cost robots specifically designed around safety and usability. However, the programming is still based on a tool centric teach-in. This paper discusses an affordance based approach for process programming in industrial manufacturing. Using low level feature detection and a consecutive evaluation, a fast programming method for industrial applications is presented. The paper presents the concept and a prototypic implementation for a welding process. Using the affordance detection, the system is able to identify relevant seams based on an image of the work space. The identified seams are then presented to the user for review with the means of augmented reality. Lastly, the system derives a welding program based on the detected seams. First experiments show promising results concerning programming speed and path accuracy for different work piece shapes and task definitions. Finally, based on the experience gained with the prototype, the outlook discusses the possibilities and further fields for future work.
  • Publication
    Cooperation of human and machines in assembly lines
    ( 2009)
    Krüger, Jörg
    ;
    Lien, Terje K.
    ;
    Verl, Alexander
    Flexibility and changeability of assembly processes require a close cooperation between the worker and the automated assembly system. The interaction between human and robots improves the efficiency of individual complex assembly processes, particularly when a robot serves as an intelligent assistant. The paper gives a survey about forms of human-machine cooperation in assembly and available technologies that support the cooperation. Organizational and economic aspects of cooperative assembly including efficient component supply and logistics are also discussed.
  • Publication
    Modelling closed-loop mechanisms in robots for purposes of calibration
    ( 1997)
    Schröer, K.
    ;
    Albright, S.L.
    ;
    Lisounkin, A.
    A method for modelling the significant parameters of closed-loop mechanisms in robots for purposes of calibration is presented. Non-linear kinematic and mechanical characteristics of the closed-loop mechanisms are modelled in such a way that they can be integrated into an open-loop manipulator model and identified. This integration is accomplished through a separation of the spatial open-loop manipulator (defining the kinematic model) and its joint-actuating mechanisms or actuator models which can be non-linear in case of closed-loop mechanisms. Identifiability of model parameters (including elasticity) is analysed and calibration results are presented.
  • Publication
    Complete, minimal and model-continous kinematic models for robot calibration
    ( 1997)
    Schröer, K.
    ;
    Albright, S.L.
    ;
    Grethlein, M.
    Presented in this paper are new general kinematic models for robot calibration. These models have the distinct advantage of satisfying the model-parameter identification requirements of completeness, minimality and model-continuity for all combinations and configurations of revolute and prismatic joints. Developed are a set of 17 model parametrizations, including simple criteria for deciding which parametrizations are to be used in modelling a robot. The presented parametrizations also result in an accurate representation of the physical robot and thus allow realistic integration of elastic deformation models. Model continuity within each parametrisation's application range is shown by means of differential geometry. Also shown is how these models are be extracted from a non-complex "vector-chain" description of a robot.
  • Publication
    Genauigkeit koordinierter Bahnbewegungen
    ( 1995)
    Spur, G.
    ;
    Feil, A.
    ;
    Schröer, K.
    Precision of coordinated path movements. Apart from motions which a machine element describes only translationally or rotationally, mainly those movements are of interest for mechanical engineering, specifically for handling and robot technology, which occur by an overlaying of elementary forms of movement. The time-related and geometrical deviations of actual from ideal movements along a path call for a systematic description. This article provides an overview of definitions of movement deviations and of the state of standardization.
  • Publication
    Calibration applied to quality control and maintenance in robot production
    ( 1993)
    Duelen, G.
    ;
    Bernhardt, R.
    ;
    Schröer, K.
    ;
    Albright, S.
    Calibration procedures using raw data from complex mechanical systems like robots can be used to obtain information about internal defects and deviations of the system. In order to use these results in diagnostic reasoning, information about their precision and reliability are required. Procedures are presented which allow such information to be obtained despite the presence of unknown and purely stochastic error sources inherent in the mechanical system.