Thorsten Schmidt

TU Dresden | TUD

Precast concrete construction enhances project efficiency, sustainability, and durability by leveraging a controlled production environment that ensures high-quality outputs. Still, the sequential nature of off-site production, encompassing casting, curing, and storage of the precast elements, is subject to significant uncertainties, including supp...

This paper introduces a novel method utilizing speech-based digital assistants and large language models (LLMs) to streamline the creation of simulation models for Job Shop Scheduling Problems (JSSP). The system simplifies the process by allowing natural language interactions for ontology-based model generation. The study evaluates the performance...

Automated material handling systems (AMHS) are essential for industrial semiconductor production in modern front-end facilities. The control of these systems has a significant impact on ensuring a reliable supply of production resources. Allocating transportation tasks to vehicles in real time is of great importance here, as it represents a computa...

This paper investigates a scheduling approach for Automated Guided Vehicle Systems, enabling transport load transfers between vehicles during transport execution. The vehicles can use predefined transfer stations to buffer transport loads until the transport continues by a following vehicle. The objective is to improve system performance by decreas...

Due to the increasing digitalization in manufacturing logistics, devices to integrate the worker into the digital manufacturing system are necessary. A voice user interface (VUI) can be considered suitable for this purpose due to its flexibility and intuitive operability. Despite the popularity and acceptance of VUIs in everyday life, their use in...

Goods receipt is an essential step in supply chains. It is often performed manually by warehouse staff. They are confronted with challenges such as time pressure , missing goods, wrong quantities, damages and incomplete documents. To support the workers in the best possible way, digital assistance systems are suitable. The study aims to investigate...

Der Beitrag zeigt, wie das Praktikum „Logistics Lab“ vor dem Hintergrund der Corona-Pandemie von einer konventionellen Präsenzveranstaltung in ein Online- und nun ein Hybridformat überführt wurde bzw. wird. Die Pandemie übernahm dabei die Funktion eines Entwicklungsbeschleunigers, da bestehende Konzepte binnen kurzer Frist hinterfragt und neu ausge...

Modular construction is generally considered to be a very efficient construction method. However, disruptions in production can negate the advantages of modular construction. Dynamic scheduling (DS) is the strategic handling of production disruptions where real-time events’ effects are mitigated by analyzing the state of the production system and a...

Der Fused-Filament-Fabrication (FFF) Prozess ermöglicht die Fertigung synthetischer Maschi-nenelemente mit porösen Füllstrukturen, die sich durch geringes Gewicht, Funktionsintegration und potenziell nachhaltige Werkstoffe wie Polylactid (PLA) auszeichnen. Gängige Ausle-gungsvorschriften berücksichtigen jedoch nicht, dass sich FFF-Maschinenelemente...

Agricultural contractors often face the complex planning problem of having to optimize the utilization of their heterogeneous vehicle fleet. In this paper, we present a mathematical model that optimizes of the logistics processes of silo corn harvest and slurry application. The model simulates the use of primary vehicles (forage harvesters or slurr...

In der Intralogistik gewinnt die Weiterentwicklung automatisierter Fahrzeugsysteme für den Transport zunehmend an Bedeutung. Die vorliegende Publikation beleuchtet mit der Einsatzplanung, der Routenplanung sowie der Sensordatenfusion drei zentrale Forschungsfelder. Das Augenmerk liegt dabei auf aktuellen Herausforderungen und etablierten Lösungsans...

A simulation framework is presented which covers both generation and simulation of production planning and control problems which include transfer times and stochastic influences and therefore extend classical multi-mode multi-project RCPSPs. This allows for systematic and in-depth investigations of the quality and the behaviour of heuristics. In a...

Additive manufacturing (AM) offers greater design freedom than conventional manufacturing processes. AM allows for components with complex infill structures of e. g. triply periodic-minimal surfaces (TPMS) that lead to significant weight reduction. Nevertheless, AM is mainly used in specialised engineering branches such as aerospace and medical eng...

Manufacturing processes are characterized by an increasing complexity , making them susceptible to failures. An effective strategy to avoid such failures , or at least to minimize their impact, is data-driven failure management. However, for many small and medium sized manufacturers, this strategy is not feasible due to a paucity of relevant failur...

Der Beitrag beschreibt ein neuartiges Konzept zur Einsatzplanung Fahrerloser Transportsysteme. Es ermöglicht den gegenseitigen Austausch von Ladungsträgern zwischen den Fahrzeugen an definierten Transferpunkten während der Transportausführung. Transfers werden ad-hoc unter Berücksichtigung des Systemzustandes geplant. Zur Berechnung der Einsatzplän...

High-strength fiber ropes have a number of advantages over steel ropes, therefore they currently enjoy great research interest in conjunction with rope winches. However, what is lacking in the art are suitable drives, since concepts for steel ropes cannot be easily transferred to high-strength fiber ropes. A promising innovative principle is the be...

Decentral production control plays a crucial role within the paradigm of Industry 4.0. Due to fast and flexible decisions on allocation and sequencing, there is no baseline schedule in advance. Moreover, the fourth industrial revolution modifies the organizational structures in the area of human resources, too. Despite changed tasks, the human is s...

Im Sinne des Buches geht es hier um einen generellen Überblick grundlegender Methodentools, die diesen Bereich flankieren. Funktionalitäten werden nur grob und beispielhaft beschrieben.

Dieses Buch widmet sich Fahrzeugsystemen für den innerbetrieblichen Transport. Dies sind neben den klassischen Gabelstaplern Routenzugsysteme, Fahrerlose Transportsysteme und Elektrohängebahnen. Die genannten Transportsysteme haben verschiedene Einsatzbereiche und unterschiedliche Vor- und Nachteile. Im Rahmen der Planung obliegt es dem Planer, das...

Technisch betrachtet sind die Transportsysteme, denen sich dieses Buch widmet, sehr unterschiedlich aufgebaut. Einige fahren auf Fahrbahnen auf dem Boden, andere bewegen sich hängend entlang einer Schiene. Manche benötigen dafür einen Menschen als Fahrer, andere sind fahrerlos unterwegs, manche können pro Arbeitsspiel genau eine Transporteinheit zu...

Die Planung eines innerbetrieblichen Transportsystems erfolgt – wie im Projektmanagement üblich – in einzelnen Phasen. Eine Vielzahl von Gründen motiviert die Einteilung in solche Phasen, die je nach Planungsstrategie sowohl streng sequenziell als auch überlappend durchgeführt werden können. Im Kern steht dabei jeweils die Zielsetzung, den Anforder...

Additive Fertigungsverfahren bieten gegenüber konventionellen eine größere Gestaltungsfreiheit, die sich in verschiedenen Vorteilen niederschlägt. Bauteile können komplexe Infillstrukturen aus dreifach-periodischen Minimalflächen (engl. triply periodic-minimal surfaces, kurz TPMS) besitzen, die zu signifikanter Gewichtsreduktion führen. Die Gestalt...

This contribution discusses a new control concept (compare Boden et al., 2021) that allows transport load exchange in hybrid AMHS. It focuses on vehicles able to perform load exchange dynamically by splitting transport requests into sub-tasks determined ad-hoc depending on the current system status. Unlike conventional control approaches for hybrid...

This paper presents the development and mathematical implementation of a production scheduling model utilizing mixed-integer linear programming (MILP). A simplified model of a real-world multi-product batch plant constitutes the basis. The paper shows practical extensions to the model, resulting in a digital twin of the plant. Apart from sequential...

Cleft lip and palate belong to the most frequent craniofacial anomalies. Secondary osteoplasty is usually performed between 7 and 11 years with the closure of the osseus defect by autologous bone. Due to widespread occurrence of the defect in conjunction with its social significance due to possible esthetic impairments, the outcome of treatment is...

Mobile, crawler and tower cranes commonly utilise multi-layer spooling drum winches. This amounts to drastically reduced wire rope service life. During operation, changing loads result in an uneven pressure distribution inside the spooling package. This produces local peaks in pressure and relative movement between rope layers, both of which cause...

The routing of a fleet of autonomous and free ranging vehicles in in-house logistics is a complex task. Generally speaking, routing requires the determination of routes between sources and sinks (route planning) and rules to deal with detecting and solving routing conflicts between vehicles during operation (dynamic motion coordination). This publi...

In this paper, we present a Constraint Programming (CP) based model for scheduling forage harvesters and transport vehicles during corn harvest. The key aspects are the synchronization of the two resource types and a forage harvester utilization depending on the number of transport vehicles supporting the harvester. The process is modelled as a pre...

This publication presents a novel simulation framework for modelling fleets of autonomous, free ranging transportation vehicles in intralogistics. It aims at overcoming current shortcomings of popular, commercial DES tools in connection with free ranging vehicles like possibilities to apply sophisticated routing strategies. It is driven by the need...

Der Beitrag führt zuerst in die Halbleiterfertigung und die damit verbundene innerbetriebliche Logistik, dabei vor allem das Transport- und Handhabungssystem, ein. Bei der Planung und Steuerung solcher Anlagen stellen sich sehr anspruchsvolle Aufgaben, die nur mithilfe der Simulation zu lösen sind. Hierzu wird dargestellt, wie sich der Simulationse...

Die Beherrschung von Fertigungszeitspreizung bei gleichzeitiger Steigerung des Nutzungsgrades und die Einhaltung der Reihenfolge sind die Gestaltungsmerkmale eines Montagesystems für kundenindividuelle Produkte bei Großserienfertigung. Deren Umsetzung leistet einen wichtigen Beitrag in der Strategie eines Premium-Automobilunternehmens. In diesem Be...

Our previous study showed the effect of pre-tension onto oscillation at the top of a ladder in raising and lowering processes on turntable ladders when steel wire ropes are added to ladder handrails. However, the oscillation was not switched off quickly. To quickly extinguish oscillation, we use steel ropes and a hydraulic system that is available...

Floor-based Automated Guided Vehicles (AGV) are important for automating transportation tasks in semiconductor manufacturing facilities. They are either used as homogenous systems in low throughput areas (see Ndiaye et al., 2016) or complementarily with ceiling-mounted Overhead Hoist Transport (OHT) systems (see Keil et al., 2018). AGV systems prov...

Die Beherrschung von Fertigungszeitspreizung bei gleichzeitiger Steigerung des Nutzungsgrades und Einhaltung der Reihenfolge sind die Gestaltungsmerkmale eines Montagesystems für kundenindividuelle Produkte bei Großserienfertigung. Deren Umsetzung leistet einen wichtigen Beitrag in der Strategie eines Premium-Automobilunternehmens. Der Aufsatz disk...

The performance of Automated Guided Vehicle systems is highly related to the implemented control strategies for vehicle fleet management. Especially the assignment of transport carriers to vehicles and the decision on the processing sequence have a high impact. So far, a dynamic transfer of transport carriers between the vehicles of an Automated Gu...

The paper at hand presents a definition of autonomous intralogistics systems and a classification of intralogistics systems with regard to their degree of autonomy. Intralogistics − a complex interplay of different logistics functions − covers the organization, control, execution and optimization of internal material and information flows. Over the...

Wie können Innovationen in der Logistik effizient und effektiv eingeführt werden? Welche Möglichkeiten gibt es, die Innovationskraft der Unternehmen in der Logistik zu steigern? Wie sind digitale Werkzeuge in Lösungen zu integrieren beziehungsweise wie sind die vorhandenen Produkte sinnvoll zu vernetzen? Diese Fragestellungen sollten etablierte Cor...

Frankfurt. Start-ups können etablierten Firmen neue Ideen liefern – so dass beide Seiten Erfolge erzielen. Eine neue Studie untersucht die Bedingungen dafür.

in Mobil-, Raupen- und Turmdrehkranen kommen häufig mehrlagig wickelnde Trommelwinden zum Einsatz. Für die eingesetzten Drahtseile geht dies mit einer deutlich geringeren Betriebsdauer einher und führt zu Mehrkosten. Wechselnde Hublasten beim Auf- und Abwickeln der Seiltrommel bilden sich inhomogene Spannungszustände aus, die zu lokalen Spannungssp...

Project Planning and Control (PPC) problems with stochastic job processing times belong to the problem class of Stochastic Resource-Constrained Multi-Project Scheduling Problems (SRCMPSP). A practical example of this problem class is the industrial domain of customer-specific assembly of complex products. PPC approaches have to compensate stochasti...

Many industry sectors benefit from the new opportunities additive manufacturing provides. Lightweight designs and integration of function are only two aspects. As there are no approaches present to insert additive manufacturing into the design of hoisting appliances though, we try to evaluate the room for improvement through experimental analysis....

Limiting global warming and increasing resource efficiency remain central tasks of our time. In the quest for sustainable development, approaches aimed at the transition from linear to circular supply chains and networks are increasingly drawing attention in research, politics and business. Industrial symbiosis is one such approach, which aims to c...

Die Aufgabe der Fördertechnik ist das Fortbewegen (Fördern) von Gütern und Personen über begrenzte Entfernung innerhalb einer örtlich begrenzten und zusammenhängenden Betriebseinheit unter Einsatz von technischen Mitteln, den Fördermitteln. Zu ihnen gehören die Fördermaschinen (s. Abschn. 14.1.2). Der Transport von Gütern und Personen über große En...

Solving Stochastic Resource-Constrained Multi-Project Scheduling Problems (SRCMPSP) is an upcoming topic. Numerous variants, smaller batch sizes and shorter product life cycles lead to more uncertainty. In Production Planning and Control (PPC), stochastic scheduling approaches are coming into focus. The schedule thus is determined during production...

Routing of multiple free ranging transportation vehicles is a complex task. All vehicles simply using the shortest possible way may lead to a lot of routing conflicts. The offline definition of a set of rules that influence the vehicles choice for a specific route can lead to longer travel distances but shorter travel times. This publication presen...

This article describes a dispatching approach for Automated Guided Vehicles with a capacity of greater than one load (referred as Multiple Load Automated Guided Vehicles). The approach is based on modelling the dispatching task as a Dial-a-Ride Problem. An Adaptive Large Neighborhood Search heuristic was employed to find solutions for small vehicle...

In this article, a generalized model in the context of logistics optimization for renewable energy from biomass is presented and analyzed. It leads us to the conclusion that demand-driven location planning approaches have to be expanded by a supply-driven one.

Simulation in the Semiconductor industry is an established method for planning greenfield projects and fab extensions as well as optimizing existing fabs and testing different scenarios for machine distribution with a constantly changing product mix. This paper discusses the importance of transportation and handling times within these simulations....

Automated Material Handling Systems are highly complex which makes planning, monitoring and optimization a challenging task. Operators of an Automated Material Handling System (AMHS) have access to extensive data from the real system and additional data sources like material flow simulation studies. Until now, these data have mainly been evaluated...

In order to ensure safe and fast transportation of wafers in 300 mm semiconductor factories, overhead transport systems (OHT) are primarily used. These systems consist of a rail network and vehicles. To avoid congestion and delays in production, high availability of individual rail sections is essential. In order to ensure this extensive preventive...

Inhomogene Spannungszustände im mehrlagig gewickelten Drahtseil infolge schwankender Hublasten verringern die Seillebensdauer signifikant. Durch eine Seilkraftregulierung bei der Bewicklung sollen solche inhomogenen Spannungszustände vermieden werden. Dieser Beitrag zeigt die Funktionsweise des hierfür entworfenen Hochleistungstreibsystems mit vorg...

During the irradiation of high molecular weight poly(tetrafluoroethylene) (PTFE) in presence of oxygen perfluoroalkyl(peroxy) radicals and functional groups are formed which allow chemical coupling reactions (cc = chemical compatibilized) with oils and plastics. Contrary to the well-known inert properties of perfluorinated organic compounds high-ef...

This paper proposes a two-stage genetic algorithm based on a simulation-based optimisation approach for generating sequencing heuristics to solve the stochastic decentralised resource-constrained multi-project scheduling problem. Processing time deviations are considered as stochastic influences. The sequencing heuristics are a simple combination o...

One approach to a more sustainable industry is the reuse of waste and by-products. In particular, the exchange of resources between companies and the reuse of energy are considered critical, as they are time-dependent and may require technical or organizational changes to the production system leading to new interdependencies between the companies....

Abstract – In order to ensure safe and fast transportation of wafers in 300 mm semiconductor factories, overhead transport systems (OHT) are primarily used. These systems consist of a rail network and vehicles. To avoid congestion and delays in production, high availability of individual rail sections is essential. In order to ensure this, normally...

Using a fleet of automated guided vehicles (AGV) is an increasingly popular option for a transportation system in semiconductor fabrication plants (fab), where AGVs can either serve as a supplement to the already existing transport system or as a first step towards the automation of transports. AGV systems have a high number of design choices, whic...

A turntable ladder is an indispensable vehicle in fire and rescue work. Vibration on the top of the ladder is considerable when the ladder set is maximally extended. It induces the discomfort and unsafety for beings in the rescue cage. Aiming at the reduction of the vibration, in this study, one additional steel wire rope is assumedly added into ea...

The huge amount of test wafers in a semiconductor production factory not only has a big impact on the total wafer inventory but on the transportation system as well. In order to analyze the effect of test wafers on the OHT system of semiconductor fabs corresponding real-world transaction data of a period of 30 days was collected. In order to show a...

The aim of this abstract is to present an exact solution method, based on a formulation as Dial a Ride Problem (DARP), to determine an optimal schedule for a single MLAGV operating in a dedicated area of a wafer fab. Since transport requests are not known in advance and the status of the system changes constantly, a schedule should be calculated in...

Uncertainties in systems and data necessitate plans that are flexible enough to be applicable in a real-time production environment. Such plans find a compromise between optimality and flexibility, frequently termed as robustness. Time is a well-known criterion for evaluating optimality of a schedule, but in the case of robustness, additional surro...

Neben dem Fortbewegen der Güter, d. h. der Überbrückung von Raum (s. Kap. 1), besteht die zweite originäre Aufgabe von Materialflusssystemen in der Überbrückung von Zeit. Die Richtlinie VDI 2411 definiert den Begriff Lagern als „jedes geplante Liegen des Arbeitsgegenstandes im Materialfluss“.

Fachwissen Logistik ist ein Schlüsselelement in allen Bereichen der Wirtschaft. Die intelligente Planung und Steuerung von Wertschöpfungsketten, Supply Chain Management (SCM), innerbetrieblich und weltumspannend, für Material- und Informationsflüsse, setzt die enge Verbindung des Wissens von Ingenieuren, Betriebswirten und Volkswirten voraus. Diese...

Die Bestimmung des Fixkostenanteils im Rahmen der Kostenauflösung erfolgt in der Praxis häufig mittels einer Punktschätzung. Diese einfache Form der Schätzung ist jedoch anfällig für Schätzfehler. Der Beitrag schlägt eine genauere und dennoch praktikable, da automatisiert berechenbare Schätzmethode vor, die die mit der Schätzung des Fixkostenanteil...

SMEs have only limited access to currently available methods for data acquisition. Manual methods usually requires a very large amount of resources and result in a limited database. Indoor tracking systems are cost-intensive, inflexible and require a high installation effort. There are currently no suitable methods available for SMEs to create a we...

In 300 mm semiconductor factories, overhead transport (OHT) systems used for safe and fast transportation of wafers. These systems consist of a rail network and OHT vehicles. The components of the rail system are subject to high stress through vehicle motion. Individual fault-related failures in the rail network can cause considerable damage and lo...

Planning, monitoring and optimizing an Automated Material Handling System (AMHS) is highly challenging. Due to the diversity of the production equipment and their arrangement, efficient handling of logistical processes is of great importance. In order not to risk the production schedule high throughputs and short delivery times need to be achieved....

Usually two user groups with different knowledge background are involved in visualizing and exploring discrete event simulation results: the simulation expert who crafted the simulation and the external user, whose system was simulated. In order to provide these results in a way that enables visual exploration of the simulation results for both type...

Zielsetzung und Fokus Die Digitalisierung gilt in der Logistik zwar als Hype, ist für viele Logistikdienstleister aber vorwiegend geprägt von Unsicherheit und Intransparenz. Allein das Verständnis des Begriffs Digitalisierung ist so breit gefasst, dass oft unklar ist, ob damit der Einsatz digitaler Werkzeuge in Unternehmen gemeint ist, oder aber di...

Läger bilden eine der Kernfunktionen innerhalb von Materialflusssystemen. In diesem Kapitel werden die wichtigsten Elemente eines Lagersystems vorgestellt. Dies bildet eine Grundlage für die Logistikplanung. Dabei werden zunächst die Aufgaben von Lägern und ihre Grundfunktionen erläutert, um im Anschluss daran die Systematik der Lagermittel vorzust...

Anhand dreier Fallbeispiele werden verschiedene Typen von Materialflusssystemen und deren Eigenschaften erläutert. Dabei werden branchenspezifische Anforderungen berücksichtigt.

Die Verpackungstechnik und die darauf aufbauende Ladeeinheitenbildung, ausgerichtet auf die Bedürfnisse des modernen Warenumschlags, stellen Basiselemente des modernen Materialflusses dar. Zur Realisierung einer optimalen Verpackung ist eine aufgabengerechte Beachtung aller ihrer möglichen Teilfunktionen zu gewährleisten. Nur bei einer durchgehende...

Allgemein umfasst der Begriff der Planung einen systematischen Prozess, bei dem Ziele und die zur Erreichung der Ziele notwendigen künftigen Handlungen festgelegt werden. Eine erfolgreiche Planung basiert auf verschiedenen Planungsgrundlagen. Zu diesen gehören neben den Grundsätzen und Axiomen der Logistikplanung die eindeutige Festlegung der Ziels...