The selective disposal of the solid waste represents one of the modern problems of the middle and low income cities around the globe, a problem that generates environmental hazards if it is not properly managed. Since...
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A comparison of two methods for the 3D shape reconstruction of a new kind of fiber-optic sensor using Fiber Bragg Gratings (FBG) is presented. The sensors, developed at the Fraunhofer Heinrich-Hertz-institute, consist...
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Within the context of Industry 4.0, future production systems are expected to support mass customization up to lot size one. In order to realize the individual production processes, a changeable and consistent integra...
Within the context of Industry 4.0, future production systems are expected to support mass customization up to lot size one. In order to realize the individual production processes, a changeable and consistent integration of assets from different manufacturers is required. Therefore, the concept of I4.0 components was developed. Every I4.0 component provides a so-called asset administration shell, i.e. a standardized virtual representation of its capabilities. This paper focuses on real-time I4.0 components that require a deterministic communication with bounded low-latency in-between. In contrast to non-real-time I4.0 components, Ethernet (IEEE 802.3) is enhanced by the new real-time communication technology Time-Sensitive Networking (TSN, IEEE 802.1). The basic configuration of TSN connections within the asset administration shell was already addressed by previous work. In this work, we present the configuration of application layer protocols using the example of OPC UA Publish/Subscribe (PubSub). More precisely, we outline the underlying concept and define additional submodels for the asset administration shell of real-time I4.0 components. Finally, we discuss the advantages of the presented approach in terms of changeability.
In process industries, compressor plants provide process mediums with certain flows and pressures. Due to corrosion, wear and fouling, the plant behavior may change throughout the entire life cycle of several decades....
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In process industries, compressor plants provide process mediums with certain flows and pressures. Due to corrosion, wear and fouling, the plant behavior may change throughout the entire life cycle of several decades. This paper presents a new model-based method for condition monitoring and diagnosis of turbo compressors, in which the characteristic operating behavior is mainly influenced by fouling. The real-time capable method is implemented on a plant control unit and validated by Hardware-in-the-Loop simulation. Furthermore, the diagnostic result is used to automatically adapt the controller behavior. The presented approach increases the original system’s resource efficiency without reducing its robustness.
Additive manufacturing is an emerging technology that enables new product design. However, major inhibitors are long building times and a fixed build direction of the workpieces. In this article, new optimization and ...
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Additive manufacturing is an emerging technology that enables new product design. However, major inhibitors are long building times and a fixed build direction of the workpieces. In this article, new optimization and path planning methods for multi-axis additive manufacturing are presented going beyond conventional three-axis systems. This includes an adaptation of the building direction and an algorithm for the special case of cylindrical axes. These methods can reduce the production time drastically by avoiding support structures and by using the integration of predefined building blocks to substitute the infill. We present both, the new manufacturing process and the necessary computation methods for optimal process and path planning. Decreasing the building time and the amount of support structures paves the way for new application domains of additive manufacturing in the future.
This paper presents an approach for persistent data backends for OPC UA namespaces. OPC UA as M2M protocol is used in various manufacturing machines and provides data access to e.g. sensors and setpoints. The central ...
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This paper presents an approach for persistent data backends for OPC UA namespaces. OPC UA as M2M protocol is used in various manufacturing machines and provides data access to e.g. sensors and setpoints. The central and persistent data storage for e.g. data-mining and condition-monitoring services in information technology infrastructures is challenging. Therefore, a holistic approach for storing OPC UA information in lightweight directory access protocol server is presented including a model for storing namespaces, information models and values in LDAP trees of scalable enterprise infrastructures to fulfil manufacturing and IT requirements in the context of Industry 4.0.
The productivity of milling machines is limited by chatter vibrations. Stability lobe diagrams (SLD) allow the selection of suitable process parameters to maximize the productivity. However, the calculation of SLDs is...
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The productivity of milling machines is limited by chatter vibrations. Stability lobe diagrams (SLD) allow the selection of suitable process parameters to maximize the productivity. However, the calculation of SLDs is very time-consuming and requires complex experiments. In this article a new online learning method is presented, which allows the calculation of SLDs during the production process. The algorithm is a combination of reinforcement learning and nearest-neighbor-classification and allows the estimation of the stability border based on measured vibration signals during machining. The proposed algorithm is capable of being continuously trained with sorted input data. A trust criterion is introduced, which allows judging the prediction quality of the algorithm. The algorithm is validated with analytical benchmark functions and with a 2-DOF milling stability simulation.
In this paper the concept of reinforcement learning agent is presented, which can deduce the correct control policy of a plant by acting in its digital twin (the HiL simulation). This way the agent substitutes a real ...
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ISBN:
(纸本)9781538694633;9781538692097
In this paper the concept of reinforcement learning agent is presented, which can deduce the correct control policy of a plant by acting in its digital twin (the HiL simulation). This way the agent substitutes a real control system. By using reinforcement learning methods, a proof of concept application is presented for a simplistic material flow system, with the same type of access to the digital twin which a PLC controller-hardware would have. With the presented approach the agent is able to find the correct control policy.
In this paper, an approach to capture and visualize the impact of a geometrical adjustments of a cable-driven parallel robot is presented. This method combines the precision of an analytic description with the efficie...
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In this paper, an approach to capture and visualize the impact of a geometrical adjustments of a cable-driven parallel robot is presented. This method combines the precision of an analytic description with the efficiency of numeric methods. The translational workspace of the robot, corresponding to a set of geometrical parameters, is determined by a piecewise assembly of boundary segments. The intersections of the curves, defining the workspace border, are computed by utilizing their shape as conic sections. Calculation examples are also given, comparing the impact of different parameter sets on the workspace.
Advanced learning methods enable the model-based control of systems with complex unknown dependencies. Within the German cluster of excellence “Internet of Production”, a configuration for an interconnected data-bas...
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Advanced learning methods enable the model-based control of systems with complex unknown dependencies. Within the German cluster of excellence “Internet of Production”, a configuration for an interconnected data-base is proposed, where data-driven model-based control strategies can be applied using the collective knowledge and adapted online according to data. For the exchanged data it is imperative to establish a generalizing learning technique for the controller design. A machine learning technique with inherent generalization ability is the Support Vector machines (SVM) algorithm, where the choice of kernel is crucial for the resulting model quality. In the related literature, usually a radial basis function (RBF) is chosen as kernel, although many studies show the necessity of a more sophisticated kernel selection. This work tackles the point of a kernel selection based on composite kernel search in context of data-driven model-based control of a CNC machining center. The results support the capability of the presented approach to further automate and improve the identification of the controller model for the machining center.
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