Simulation-based planning of Motion Sequences for Automated Procedure Optimization in Multi-Robot Assembly Cells

This work has been submitted to the IEEE for possible publication. Abstract --Reconfigurable multi-robot cells offer a promising approach to meet fluctuating assembly demands. However, the recurrent planning of their configurations introduces new challenges, particularly in generating optimized, coordinated multi-robot motion sequences that minimize the assembly duration. This work presents a simulation-based method for generating such optimized sequences. While core operations are constrained and predetermined, traverse operations offer substantial optimization potential. Scheduling the core operations is formulated as an optimization problem, requiring feasible traverse operations to be integrated using a decomposition-based motion planning strategy. Several solution techniques are explored, including a sampling heuristic, tree-based search and gradient-free optimization. For motion planning, a decomposition method is proposed that identifies specific areas in the schedule, which can be solved independently with modified centralized path planning algorithms. The proposed method generates efficient and collision-free multi-robot assembly procedures that outperform a baseline relying on decentralized, robot-individual motion planning. Its effectiveness is demonstrated through simulation experiments. Note to Practitioners-- In practice, robotic motions in multi-robot assembly cells are often handcrafted for specific tasks, requiring significant effort and lacking scalability. This paper presents a novel method for optimizing robotic motion sequences and their execution schedules with the goal of minimizing the assembly duration. Existing approaches for combined task and motion planning often rely on high-level heuristics, impose restrictive constraints on planning, or demand excessive computational resources. . The proposed method separates task-related motions, which perform essential transformations on the assembly product, from connecting traverse motions.