Bengt Mueck

Virtual and augmented reality support for discrete manufacturing system simulation

Nowadays companies operate in a difficult environment: the dynamics of innovations increase and product life cycles become shorter. Furthermore products and the corresponding manufacturing processes get more and more complex. Therefore, companies need new methods for the planning of manufacturing systems. One promising approach in this context is digital factory/virtual production-the modeling and analysis of computer models of the planned factory with the objective to reduce time and costs. For the modeling and analysis various simulation methods and programs have been developed. They are a highly valuable support for planning and visualizing the manufacturing system. But there is one major disadvantage: only experienced and long trained experts are able to operate with these programs. The graphical user interface is very complex and not intuitive to use. This results in an extensive and error-prone modeling of complex simulation models and a time-consuming interpretation of the simulation results. To overcome these weak points, intuitive and understandable man-machine interfaces like augmented and virtual reality can be used. This paper describes the architecture of a system which uses the technologies of augmented and virtual reality to support the planning process of complex manufacturing systems. The proposed system assists the user in modeling, the validation of the simulation model, and the subsequent optimization of the production system. A general application of the VR- and AR-technologies and of the simulation is realized by the development of appropriate linking and integration mechanisms. For the visualization of the arising 3D-data within the VR- and AR-environments, a dedicated 3D-rendering library is used.

Using dynamic multiresolution modelling to analyze large material flow systems

The interactive, simulation-aided analysis of material flow systems is often done with the help of virtual reality. If a user wants to influence the simulation run, the simulation and the visualization have to be computed simultaneously. Large, detailed simulation models, which can not be calculated fast enough, can not be analyzed interactively. This paper presents a method which only computes those parts of simulation models that are visited by the user. If a user shifts its attention, the area being simulated in detail is updated. Since the major part of the simulation is not detailed, the necessary calculating complexity is reduced. On the basis of models allowing a multiresolution simulation methods are introduced which regulate the level of detail based on the evaluation of the users attention. Changing the levels of details leads to the exchange of models with different level of details.

Multi-user support and motion planning of humans and humans driven vehicles in interactive 3D material flow simulations

The visualization of simulated production processes is used for their analysis. Huge plants are normally planned by a team. So a solution for many users who are modeling and interacting with a running model in an immersive 3D environment is required. We discuss an approach where several users work cooperatively on one simulation model. To optimize their work, the users need some guidance. For this we suggest small maps and arrows to guide the user to significant objects (machines). In many production scenarios, objects (forklifts, workers) are moving in an unguided fashion. In actual implementations these paths have to be modeled manually. In spite of taking these efforts, we are presenting an automated approach which is based on the 3D layout of the plant. If the user as part of the simulation is standing in the way of the object, the object stops in our approach (as hopefully in reality).

A two-tier method for evaluating alternative policies to support interactive analysis of 3D material flow simulations

Discrete event material flow simulation tools have long been offering real time 3D visualization. This feature allows less experienced users to analyze the underlying system. Beyond this, visualization is not used to interact with the simulated (underlying manufacturing) system to improve or control the material flow, especially under disturbances. This paper presents a simulation based 2-tier framework, which seeks to control or improve material flow by means of real time user immersive visualization. The first tier uses static optimization to compute the material flow by selecting from a large number of alternative policies based on deterministic disturbances. The second tier is a reactive algorithm which computes solutions for probabilistic disturbances. The results of the two tiers are used for interacting with the underlying system using visualization. We show that the proposed system is able to handle complex alternative policies, which supports interactive analysis of 3D material flow simulations.

Augmented Reality applications for Warehouse Logistics

The costs for material flow and logistics generate a major part of the prime costs for a product. Thereby warehouse and distribution logistics take an outstanding position in inner- and outer operational supply chain. Under the circumstances that on average 2/3rd of the operational costs for logistics are accounted for warehouse management tasks, it is clear evidently that these costs have a decisive influence on the competitive position of a company. As part of a cooperative project of the “Logistics & Assembly Systems” of Siemens AG, one of the leading companies in logistics and production automation, and the department for Computer Integrated Manufacturing of the University of Paderborn, the worlds first Augmented Reality based picking system was developed in the labs at Heinz Nixdorf Institute Paderborn. The prototype that emanated from the development process has been approved in extensive tests under laboratory conditions. The evaluation of the test results verified the potential to improve the work flow and picking efficiency with an Augmented Reality based picking system.

Simulation in business administration and management

Today the simulation of production processes is applied in various areas of planning. Specialized tools support the modeling, the execution, and the analysis of simulations. Layouts as well as dimensioning and processes can be optimized using a computer with these tools. Simulation processes are easier understood and communicated by 3-dimensional visualizations of production processes. Movements of robots can be programmed and examined directly in simulation tools. If simulations are coupled, models which were modeled with different simulations can be put together in one model.

Einsatzpotenziale der Technologie Augmented Reality

Kurzfassung Die Simulation von Produktionsabläufen ist heutzutage ein verbreitetes Instrument. Mit ihr können sowohl strategische als auch taktische Entscheidungen abgesichert werden. Ist ein Modell für einen Prozess einmal geschaffen, lassen sich schnell verschiedene Varianten des Prozesses analysieren. Auch Fragen, wie z.B. „Wie viel mehr kann ich durch den Einsatz eines weiteren Flurfördergeräts produzieren?“, sind einfacher zu beantworten. Der Modellierung und Analyse von Materialflüssen kommt somit eine sehr hohe Bedeutung zu. In diesem Zusammenhang werden beispielsweise Programme wie eM-Plant und eM-Workplace der Firma Tecnomatix oder Taylor ED von Enterprise Dynamics eingesetzt, um den oben genannten Planungsprozess zu unterstützen. Nachteil dieser Systeme ist aber das wenig intuitive User-Interface. Es erfordert in der Regel sehr gut geschulte Benutzer, sodass die Erzeugung komplexer Simulationsmodelle mit einem hohen Zeitaufwand verbunden ist. Durch die Nutzung einer innovativen Mensch-Maschine-Schnittstelle, wie der AR-Technologie, können diese Nachteile eliminiert werden.