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Automated Generation of Precedence Graphs in Digital Value Chains for Automotive Production

Hake, Cornelius, Friedrich, Christian

arXiv.org Artificial Intelligence

--This study examines the digital value chain in automotive manufacturing, focusing on the identification, software flashing, customization, and commissioning of electronic control units in vehicle networks. A novel precedence graph design is proposed to optimize this process chain using an automated scheduling algorithm, which combines structured data extraction from heterogeneous sources via natural language processing and classification techniques with mixed integer linear programming for efficient graph generation. The results show significant improvements in key metrics. The algorithm reduces the number of production stations equipped with expensive hardware and software to execute digital value chain processes, while also increasing capacity utilization through efficient scheduling and reduced idle time. T ask parallelization is optimized, resulting in streamlined workflows and increased throughput. Compared to the traditional scheduling method, the automated approach has reduced preparation time by 50% and reduced scheduling activities, as it now takes two minutes to create the precedence graph. The flexibility of the algorithm's constraints allows for vehicle-specific configurations while maintaining high responsiveness, eliminating backup stations and facilitating the integration of new topologies. Automated scheduling significantly outperforms manual methods in efficiency, functionality, and adaptability.


Non-Crossing Anonymous MAPF for Tethered Robots

Peng, Xiao, Simonin, Olivier, Solnon, Christine

Journal of Artificial Intelligence Research

The goal is to find a set of non-crossing paths such that the makespan is minimal. A difficulty comes from the fact that a safety distance must be maintained between two robots when they pass through the same subpath, to avoid collisions and cable entanglements. Hence, robots must be synchronized and waiting times must be added when computing the makespan. We show that bounds can be efficiently computed by solving linear assignment problems. We introduce a variable neighborhood search method to improve upper bounds, and a Constraint Programming model to compute optimal solutions. We experimentally evaluate our approach on three different kinds of instances.


Winning Solution of the AIcrowd SBB Flatland Challenge 2019-2020

Andreica, Mugurel-Ionut

arXiv.org Artificial Intelligence

This report describes the main ideas of the solution which won the AIcrowd SBB Flatland Challenge 2019-2020, with a score of 99% (meaning that, on average, 99% of the agents were routed to their destinations within the allotted time steps). The details of the task can be found on the competition's website. The solution consists of 2 major components: 1) A component which (re-)generates paths over a time-expanded graph for each agent 2) A component which updates the agent paths after a malfunction occurs, in order to try to preserve the same agent ordering of entering each cell as before the malfunction. The goal of this component is twofold: a) to (try to) avoid deadlocks b) to bring the system back to a consistent state (where each agent has a feasible path over the time-expanded graph) I am discussing both of these components, as well as a series of potentially promising, but unexplored ideas, below. The invariant for this component is that every agent always has an assigned path (where it will be located at each time step over the whole time horizon), and this component only tries to improve the overall path assignment). Initially, all the agents have a default path assigned which doesn't enter the environment at all (they always just stay at their initial location, outside the environment).


Assembly line balancing with task division

Silva, Carlos Alexandre X., Foulds, Les, Longo, Humberto J.

arXiv.org Artificial Intelligence

In a commonly-used version of the Simple Assembly Line Balancing Problem (SALBP-1) tasks are assigned to stations along an assembly line with a fixed cycle time in order to minimize the required number of stations. It has traditionally been assumed that the total work needed for each product unit has been partitioned into economically indivisible tasks. However, in practice, it is sometimes possible to divide particular tasks in limited ways at additional time penalty cost. Despite the penalties, task division where possible, now and then leads to a reduction in the minimum number of stations. Deciding which allowable tasks to divide creates a new assembly line balancing problem, TDALBP (Task Division Assembly Line Balancing Problem). We propose a mathematical model of the TDALBP, an exact solution procedure for it and present promising computational results for the adaptation of some classical SALBP instances from the research literature. The results demonstrate that the TDALBP sometimes has the potential to significantly improve assembly line performance.