A more efficient cutting planes approach for the green vehicle routing problem with capacitated alternative fuel stations

The Green Vehicle Routing Problem with Capacitated Alternative Fuel Stations assumes that, at each station, the number of vehicles simultaneously refueling cannot exceed the number of available pumps. The state-of-the-art solution method, based on the generation of all feasible non-dominated paths, performs well only with up to 2 pumps. In fact, it needs cloning the paths between every pair of pumps. To overcome this issue, in this paper, we propose new path-based MILP models without cloning paths, for both the scenario with private stations (i.e., owned by the fleet manager) and that with public stations. Then, a more efficient cutting plane approach is designed for addressing both the scenarios. Numerical results, obtained considering a set of benchmark instances ad hoc generated for this work, show both the efficiency and the effectiveness of this new cutting plane approach proposed. Finally, a sensitivity analysis, carried out by varying the number of customers to be served and their distribution, shows very good performances of the proposed approach.

Mobile Roboter zur freien Verkettung von Montagestationen*/Mobile Robots for Dynamically Interconnecting Assembly Stations – How can mobile robots be developed and deployed to provide a flexible transport system?

Moderne Produktionssysteme müssen stetig steigenden Herausforderungen, zum Beispiel durch die Individualisierung von Produkten oder gestiegene Variantenvielfalt, genügen und daher hoch flexibel sein. Die klassische, verkettete Produktion stößt dabei zunehmend an ihre Grenzen. Das Werkzeugmaschinenlabor WZL der RWTH Aachen und das Fraunhofer-Institut für Produktionstechnologie IPT entwickeln daher im BMBF-geförderten Forschungsprojekt „freeMoVe“ gemeinsam mit Industrieunternehmen eine neue Montageorganisationsform, die „freie Verkettung“. Der Beitrag beschreibt den Einsatz mobiler Roboter für Transport und Handling in frei verketteten Montagesystemen. Beschrieben werden die Anforderungen an mobile Roboter, die technischen und organisatorischen Herausforderungen, die Sicherheit für den Menschen beim Einsatz mobiler autonomer Roboter, die Ansteuerung der Roboter mittels eines Flottenmanagers sowie die Einbindung der Roboter in das Gesamtkonzept der frei verketteten Montage.   Customer-specific products, a wide variety of variants and high flexibility: Modern production systems have to meet constantly increasing challenges such as individualization or high variation of products and high flexibility. Classic, rigidly linked production is increasingly reaching its limits. The Fraunhofer Institute for Production Technology IPT and the Laboratory for Machine Tools and Production Engineering WZL of RWTH Aachen University are therefore working with industrial partners in the BMBF-funded research project freeMoVe to develop a new organisational form of assembly, the so-called dynamically interconnected assembly. This article therefore describes the use of mobile robots for transport and handling in dynamically interconnected assembly systems. The requirements for mobile robots, the technical and organisational challenges, the safety for humans, when using mobile autonomous robots, the control of the robots by means of a fleet manager and the integration of the robots into this overall new concept of assembly organisation are described.

The Role of E-Services in the Transition from the Product Focus to the Service Focus in the Printing Business

Today, many manufacturing companies are focusing on their service operations, which are often seen as a better source of revenue than the traditional product business. E-services can accelerate this process by offering companies new ways to control products and monitor equipment from a distance. This chapter describes the changes which are taking place in the printing business. It tells the story of Lexmark, a printer manufacturer that has recently created differentiated offerings to its business customers. In the case of Lexmark, this repositioning of offerings has been enabled by e-services. Here, the e-services consist of the Lexmark Fleet Manager system which monitors the use and availability of the equipment and makes suggestions on how to improve the printing processes on the customer site. The case ends with a description of the actual challenges that Lexmark is currently facing.

The Role of E-Services in the Transition from the Product Focus to the Service Focus in the Printing Business

Today, many manufacturing companies are focusing on their service operations, which are often seen as a better source of revenue than the traditional product business. E-services can accelerate this process by offering companies new ways to control products and monitor equipment from a distance. This chapter describes the changes which are taking place in the printing business. It tells the story of Lexmark, a printer manufacturer that has recently created differentiated offerings to its business customers. In the case of Lexmark, this repositioning of offerings has been enabled by e-services. Here, the e-services consist of the Lexmark Fleet Manager system which monitors the use and availability of the equipment and makes suggestions on how to improve the printing processes on the customer site. The case ends with a description of the actual challenges that Lexmark is currently facing.