Automated sequence and motion planning for robotic spatial extrusion of 3D trusses

TL;DR

This paper introduces a novel hierarchical planning framework and CSP-based formulation for automated sequence and motion planning in robotic spatial extrusion of complex 3D trusses, supported by open-source software and real-world case studies.

Contribution

It is the first to rigorously formulate the extrusion sequence and motion planning problem for unconstrained topologies and to develop an efficient hierarchical solution framework.

Findings

Decoupled sequence and motion planning improves efficiency.

Provides detailed runtime analysis of SAMP problems.

Demonstrates successful real-world fabrication and simulation cases.

Abstract

While robotic spatial extrusion has demonstrated a new and efficient means to fabricate 3D truss structures in architectural scale, a major challenge remains in automatically planning extrusion sequence and robotic motion for trusses with unconstrained topologies. This paper presents the first attempt in the field to rigorously formulate the extrusion sequence and motion planning (SAMP) problem, using a CSP encoding. Furthermore, this research proposes a new hierarchical planning framework to solve the extrusion SAMP problems that usually have a long planning horizon and 3D configuration complexity. By decoupling sequence and motion planning, the planning framework is able to efficiently solve the extrusion sequence, end-effector poses, joint configurations, and transition trajectories for spatial trusses with nonstandard topologies. This paper also presents the first detailed computation data to reveal the runtime bottleneck on solving SAMP problems, which provides insight and comparing baseline for future algorithmic development. Together with the algorithmic results, this paper also presents an open-source and modularized software implementation called Choreo that is machine-agnostic. To demonstrate the power of this algorithmic framework, three case studies, including real fabrication and simulation results, are presented.