Offline Pose Generation and Multi-Objective Hole-Sequence Optimization for Five-Axis Multi-Hole Drilling on Complex Surfaces: A Numerical Framework

This study presents a numerical framework for offline three-objective hole-sequence planning for an AC dual-rotary-head five-axis system. A double-curvature surface containing 48 staggered holes is used as a numerical case. For each hole, one representative inverse-kinematic branch is fixed, and the visitation permutation is the sole decision variable. The objectives minimize cumulative non-cutting tool-center-point (TCP) distance, cumulative A/C-axis adjustment, and estimated synchronized repositioning time. NSGA-II and NSGA-III are compared in 30 paired runs under identical computational settings. NSGA-II provides better median hypervolume and cross-fitted IGD+ and, relative to serpentine scanning, its compromise sequence reduces the three objectives by 6.631%, 56.254%, and 36.939%, respectively. Nearest-neighbor sequencing reduces TCP distance but increases rotary adjustment and estimated time. Diagnostics examine acceleration-aware timing, objective-count effects, selection preferences, inverse-kinematic branch choices, initial/return states, and finite C-axis windows. The results show that geometric proximity alone does not represent five-axis repositioning cost and that the time objective depends on relative axis-speed and dynamic assumptions. The reported improvements are numerical predictions for the synthetic geometry and virtual parameters; machine-specific post-processing, collision verification, digital-twin simulation, and dry-run validation remain necessary before industrial deployment.