Coordinated Multi-arm 3D Printing using Reeb Decomposition

Robotic additive manufacturing has the potential to replace traditional production techniques with more flexible, capable and efficient methods. However, this potential has not yet been realized due to the intrinsic physical limitations of extruders. Thus improved speed and efficiency lies in coordinated fabrication by multiple extruders. In this paper, we propose a framework for utilizing multiple extruders to collaboratively fabricate objects in a shared workspace. In contrast to related work, we make use of a Reeb decomposition method of the input model, which dramatically reduces the search space over feasible toolpaths but still results in highly effective allocation of model components to each extruder. We demonstrate superior performance of our approach in simulation as well as in hardware with a two-robot arm extruder system. When compared to a single extruder approach over a benchmark of 14 models, our method achieves a mean improvement of 72% in extruder utilization. When compared to two additional toolpath planning methods for multiple extruders, only our method is able to successfully complete a valid toolpath on all models. Prior methods fail on more than half of our benchmark due to reaching deadlocked states during toolpath planning. On the models for which all methods succeed, our approach achieves mean utilization improvements of 132% over zone-blocking and 12% over contour greedy. We demonstrate that our approach is also suitable for models with non-planar slicings, which yield further improvements in extruder utilization. For more results and information see: https://sites.google.com/view/multi-arm-reeb.