Design for Manufacturing: A Manufacturability Knowledge-Integrated Reinforcement Learning Framework for Free-Form Pipe Routing in Aeroengines

2026-05-19

AI Summary

This study addresses the disconnect between design and manufacturing in freeform tubular routing for aero-engines, which traditionally relies on manual trial-and-error. The authors formulate path planning as a boundary value problem in the Frenet frame, representing trajectories via curvature and torsion profiles, and—uniquely—embed manufacturing constraints directly into a reinforcement learning framework. They propose a Frenet-frame-based path representation coupled with a staged guidance reward mechanism, integrating cubic Hermite interpolation with proximal policy optimization to establish a closed-loop design-to-manufacturing pipeline. A unified mapping model directly generates toolpaths for six-axis tube-bending machines. Experiments demonstrate that the proposed method significantly outperforms existing approaches in end-point alignment, length control, obstacle avoidance, and manufacturability, achieving faster convergence; physical validation confirms high fidelity between fabricated components and digital designs.

Abstract

Design for manufacturing plays a critical role in advanced aeroengine development, where complex components necessitate careful consideration of manufacturability. However, current practices in pipe routing remain largely decoupled from down-stream manufacturing, leading to labor-intensive, trial-and-error iterations to achieve manufacturable designs. To address this problem, this study proposes the Frenet-based pipe routing optimization (FPRO) framework, a manufacturability knowledge-integrated reinforcement learning approach for free-form pipe design in aeroengines. FPRO formulates the routing problem as a boundary value problem in the Frenet frame. In this framework, the pipe path is represented by curvature and torsion profiles, which are generated using cubic Hermite interpolation. To integrate design and manufacturing, domain-specific manufacturing knowledge is embedded as constraints on the permissible ranges of curvature and torsion. The path optimization is performed using the proximal policy optimization algorithm with stochastic exploration and a stage-guided reward mechanism. A unified mapping formulation then translates the optimized path into motion trajectories for the bending die, enabling direct fabrication on a six-axis free-bending machine. Experimental results demonstrate that FPRO consistently generates collision-free, manufacturable paths with smoother geometric profiles compared to Cartesian-based methods. It also achieves faster convergence and superior performance in terminal alignment, path length, obstacle avoidance, and manufacturability compared to state-of-the-art reinforcement learning baselines. Real-world validation confirms the close geometric correspondence between the manufactured pipe and its digital design, validating the practical feasibility of FPRO.

Problem

• Design for Manufacturing
• Pipe Routing
• Aeroengines
• Manufacturability
• Free-Form Design

Innovation

• reinforcement learning
• design for manufacturing
• Frenet frame
• pipe routing
• free-bending