This dissertation focuses on the material transport system design problem (MTSDP), integrating decisions of technology selection and flow network design. This research is motivated by the design of material transport systems (MTS) in manufacturing plants. The objective is to design a MTS with minimum lifetime costs, subject to service requirements, flow network restrictions, and limited resources. We characterize the MTSDP from the perspectives of task requirements, transport technology, and space utilization. A classification is proposed for transport technologies such that instances in the same class share the same properties, and a decision framework is proposed to emphasize the inter-relationships of three major decisions: task clustering, network connecting, and technology selection. We consider fixed and variable costs, arc capacities, and empty travel in our formulations. We propose two solution approaches for the MTSDP. The first is the compact formulation (CF) approach where the three major decisions are handled by a mixed integer non-linear programming (MINLP) formulation. Relaxation techniques are applied to linearize the model. The solution of the resulting linear formulation (MILP) provides a lower bound to that of MINLP. A tightened formulation reduces the computational time by a factor of 3.85. The experiment also shows that when control system costs are significant, designs with multiple-task clusters are more economical than those restricted to single-task clusters. The other approach is clustering/set partition (CSP), where the three decisions are decomposed and solved sequentially. In an example MTS design problem, three methods are compared: CSP, a GREEDY approach from the literature, and enumeration. CSP finds the optimal solution, while GREEDY results in 31% greater costs. A similar comparison with another example is made for the CF and CSP approaches. We apply the CSP approach in a case problem, using data from an auto parts manufacturer. We include flow path crossing constraints and perform experiments to determine solution quality over a range of small problem sizes. The largest difference from optimality is 3.34%, and the average is 0.98%. More importantly, based on these experiments, it seems there is no evidence that the difference percentage grows with an increase in the number of tasks.

Die Arbeit beschreibt ein Modell, dass den Materialfluss in Transport- und Puffersystemen mit Hilfe eines agenten-basierten Ansatzes realistisch abbildet. Auf der Basis von Produktionsprogrammen werden individuelle Güter in beliebigen Netzwerkstrukturen mit Hilfe direkter und indirekter Interaktionen behinderungsvermeidend gesteuert. / The thesis describes a model that realistically illustrates the material flow in transport and buffer systems by means of an agent-based approach. Individual goods are steered hindrance-avoiding in arbitrary network structures based on production programs by means of direct and indirect interactions.

In der Intralogistik führen technologieabhängig gekoppelte, drehzahlvariable Mehrmotorensysteme zu hohen Schwankungen im elektrischen Leistungsbedarf, der u.a. von der transportierten Gütermenge abhängt. Aufgrund der Überlappung der Lastanforderungen einzelner Verbraucher entstehen beträchtliche Lastmaxima, die das Versorgungsnetz belasten und eine Überdimensionierung der Infrastruktur erfordern. Ein räumlich ausgedehnter Gleichspannungsverbund in Kombination mit einem Energiespeichersystem sowie die Anpassung der Steuerung bieten Lösungen zur Verringerung der Netzanschlussleistung und des Energiebedarfs. Darüber hinaus ermöglichen solche Systeme eine effektive Rückgewinnung von potentieller und Bremsenergie. Am Beispiel eines Lagersystems mit Regalbediengeräten wird ermittelt, welche Reduktion des Netzleistungsbedarfs und Energieverbrauchs erreicht werden kann. Dabei werden ebenfalls die Auswirkungen auf die Durchsatzleistung des Systems untersucht. Dazu kommen Modelle des Bewegungsablaufes, der Komponenten der Antriebsstränge mit Abbildung von Mechanik, Getriebe, Motoren, Umrichter und der Speicher in einem Materialflussmodell zum Einsatz. Die Materialflusssimulationsumgebung wird dazu um die kontinuierlichen Modelle zu einem kombinierten Systemmodell erweitert und leistungsbegrenzende Steuerungsansätze im Zusammenwirken mit dem erweiterten Gleichspannungsverbund sowie den elektrischen Speichersystemen analysiert. Abschließend erfolgt die Ermittlung der Wirtschaftlichkeit der einzelnen Lösungen. Das Ergebnis ist ein Verfahren zur effizienten Betriebsweise von Intralogistiksystemen sowie eine Methode zur Dimensionierung eines räumlich ausgedehnten Gleichspannungsverbunds mit elektrischem Speicher. Zusammenfassend werden wirtschaftliche Maßnahmen identifiziert, die elektrische Lastmaxima reduzieren, die Schwankungen in der externen Energieversorgung verringern und die Energieeffizienz von Intralogistiksystemen verbessern. / In intralogistics, technologically linked, variable-speed multi-motor systems cause high fluctuations in electrical power demand due to variations in the amount of transported goods. These fluctuations often result in overlapping load demands by various consumers, which strain the supply network and require overdimensioning of infrastructure. To address this issue, a physically extended DC link, in combination with an energy storage system as well as adapted control, can reduce both grid power demand and energy consumption while allowing for the recovery of potential and braking energy. To evaluate the achievable reduction of grid power and energy demand, models were developed for individual components such as drive trains with motor, inverter, storage, axis coordination and material flow simulation with sequence control. An example of a warehouse system with storage and retrieval machines was used to determine the effects on throughput performance. To achieve this, the material flow simulation environment was extended to a combined system model, and performance-limiting control approaches were analyzed in interaction with the extended DC link and storage. Subsequently, economic feasibility of the individual solutions was determined. The result is a procedure for efficient operation of intralogistics systems and a methodology for dimensioning a physically extended DC link with electrical storage. The overall objective was to identify economic solutions that reduce electrical load peaks, balance external energy supply, and make intralogistics systems more energy-efficient. In conclusion, this study identifies economically viable solutions that can reduce electrical load peaks, balance external energy supply, and improve energy efficiency of intralogistics systems.