Planung und Steuerung des Werkzeug- und Formenbaus auf Basis eines integrierten Produktmodells

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Integration of Expert Judgment into Remaining Useful Lifetime Prediction of Components

AbstractAccurate estimates of renewal instances are necessary to avoid both machine breakdowns as well as unnecessary replacements. These instances are based upon a prognosis of the remaining useful lifetime of the components investigated but their usability is limited because of insufficient failure time data. Therefore the paper at hand deals with the integration of expert knowledge into lifetime estimation methods to enhance the prediction result. A model has been developed and simulated. Furthermore a parameter study analyzes the model's effectiveness, which produces promising results

Spare Parts Planning for Offshore Wind Turbines Subject to Restrictive Maintenance Conditions

AbstractThe use of offshore wind energy is supposed to play a significant role in future energy supply. Because offshore wind farms will be built in greater water depths and distances to shore according to other already realized offshore projects, maintenance is far more influenced by different restrictive factors. Limited availability of vessels, dependency on meteorological surrounding conditions, such as wind speed and weave height, as well as a complex logistical process chain require adjustment of up to now implemented maintenance concepts. In this context ensuring a reliable and cost-effective supply of spare parts is of great importance. This paper describes an approach for spare parts planning by considering restrictions that exist in the field of offshore maintenance. The model developed is used to show how restrictive factors influence maintenance and operation costs and how spare parts supply processes can be adopted. Scenario analysis will be used to estimate time of preventive maintenance activities and to investigate stock out costs caused by the restrictive accessibility

Annals of Scientific Society for Assembly, Handling and Industrial Robotics 2021

This Open Access proceedings presents a good overview of the current research landscape of assembly, handling and industrial robotics. The objective of MHI Colloquium is the successful networking at both academic and management level. Thereby, the colloquium focuses an academic exchange at a high level in order to distribute the obtained research results, to determine synergy effects and trends, to connect the actors in person and in conclusion, to strengthen the research field as well as the MHI community. In addition, there is the possibility to become acquatined with the organizing institute. Primary audience is formed by members of the scientific society for assembly, handling and industrial robotics (WGMHI)

Conceptual Approach of Robustness in Logistical Control

The logistical control and order release of structurally dynamic systems represent a great challenge. In contrast to classical shop floor production, these systems can involve transitions between the two different organizational forms job shop production and flow production. This results in a system that is susceptible to turbulence and malfunctions. This paper presents an approach that improves the robustness of these systems and achieves a stable system state even under external influences. Decentralized stock control loops control the WIP of the individual stations in a closed loop. When organizational transitions occur, interlinking losses arise, which reduce the productivity of the system. Similar effects can cause disturbances and blockages. The introduction of a robustness controller adapts the input parameters of the order release to the current system status, so that an adapted reaction takes place in the event of strong disturbances

Numerical simulation and statistical analysis of a cascaded flexure hinge for use in a cryogenic working environment

Due to their many advantages, flexible structures are increasingly being used as guide and transmission elements in handling systems. Prismatic solid-state joints with a concentrated cross-sectional reduction are predominantly used as flexure pivots for both microscopic and macroscopic designs. A transfer of these geometries to applications in cryogenic working environments is not easily possible at temperatures below -130 °C due to the changed material properties. In this paper, the further development of swivel joints as cascaded solid state joints for such a cryogenic environment is illustrated by the targeted adaptation of certain joint parameters and dimensions. By means of a comprehensive FEM simulation, it can be shown how the influence of specific parameters affects movement accuracy, process forces and shape stability and to what extent these geometric parameters influence each other in their effect

Correlation between Geometric Component Properties and Physical Parameters of an Aerodynamic Feeding System

In previous research, an aerodynamic feeding system was developed, which autonomously adapts to different components by using a genetic algorithm that controls the physical parameters of the system (e.g. angle of inclination, nozzle pressure). The algorithm starts with two individuals with random values, generated within the boundaries of the parameters set by the user. Due to this, the setting time - the time that passes until a satisfactory orientation rate is reached - is hard to predict. The aim of this work is to identify basic interactions of geometric component properties with the physical parameters of the aerodynamic feeding system to determine in which areas of the workspace a satisfactory solution can be expected. By doing so, the initial population of the genetic algorithm can be generated based on certain geometric properties and would therefore no longer be random, presumably reducing setting time. To identify interactions of component properties and system parameters, exemplary components were developed. They represent relevant single properties that have significant impact on the aerodynamic orientation process. These components were then fed into the aerodynamic orientation process and their behavior was documented. To identify correlations between certain geometric properties and physical parameters of the feeding system, the tests were planned and carried out using Design of Experiments methods. The results of the tests were also used to determine the direct interrelations of said properties and the suitability for aerodynamic orientation

Combined Structural and Dimensional Synthesis of a Parallel Robot for Cryogenic Handling Tasks

The combined structural and dimensional synthesis is a tool for finding the robot structure that is suited best for a given task by means of global optimization. The handling task in cryogenic environments gives strong constraints on the robot synthesis, which are translated by an engineering design step into the combined synthesis algorithm. This allows to reduce the effort of the combined synthesis, which provides concepts for alternative robot designs and indications on how to modify the existing design prototype, a linear Delta robot with flexure hinges. Promising design candidates are the 3PRRU and 3PRUR, which outperform the linear Delta (3PUU) regarding necessary actuator force

Development of a Methodology for the Determination of Conceptual Automated Disassembly Systems

At a certain point in its life cycle, a product will reach a condition where it partly or completely loses its functionality. When this happens, the disassembly has the ambition to regenerate a product-value or to enable an environmental friendly product recycling. With regard to the high workload and costs for manual labor one approach to increase the productivity of disassembly tasks is the use of automated disassembly systems (ADS). Depending on different life cycle scenarios, requirements on automated disassembly systems vary. Concerning this problem, a general methodology is developed, which enables the determination of a conceptual ADS by assigning automated modules that are processing the product disassembly. In the first place the objective of a disassembly is determined, followed by a closer investigation of the product. Thereby target components are defined, which has to disassembled. By looking at the connections between these target components suitable separation procedures are derived. Finally, modules of the automated disassembly system are determined

LiDAR-Based Localization for Formation Control of Multi-Robot Systems

Controlling the formation of several mobile robots allows for the connection of these robots to a larger virtual unit. This enables the group of mobile robots to carry out tasks that a single robot could not perform. In order to control all robots like a unit, a formation controller is required, the accuracy of which determines the performance of the group. As shown in various publications and our previous work, the accuracy and control performance of this controller depends heavily on the quality of the localization of the individual robots in the formation, which itself depends on the ability of the robots to locate themselves within a map. Other errors are caused by inaccuracies in the map. To avoid any errors related to the map or external sensors, we plan to calculate the relative positions and velocities directly from the LiDAR data. To do this, we designed an algorithm which uses the LiDAR data to detect the outline of individual robots. Based on this detection, we estimate the robots pose and combine this estimate with the odometry to improve the accuracy. Lastly, we perform a qualitative evaluation of the algorithm using a Faro laser tracker in a realistic indoor environment, showing benefits in localization accuracy for environments with a low density of landmarks