Multi-Objective Trajectory Optimization of a 7-DOF Wiring Robot for Aircraft Harness Layout on Fixture Boards

Aircraft wire-harness routing on fixture boards requires not only efficient large-workspace robot motion but also smooth and process-safe passage around densely distributed pins. Conventional robot trajectory optimization generally focuses on generic motion indices and cannot explicitly represent local over-bending risk and coupled wiring-process constraints. This paper proposes a process-safety-aware multi-objective trajectory optimization method for a seven-axis wiring robot composed of a linear rail and a six-DOF manipulator. An executable reference trajectory is parameterized using quintic B-splines, and execution time, normalized joint jerk, and a pin-neighborhood weighted bending-safety proxy are jointly optimized under robot-motion, pin-passing, board-clearance, and non-target-pin constraints. A constraint-guided adaptive DE-NSGA-II algorithm is developed to improve feasible-solution search in the resulting narrow and strongly coupled feasible region. Physical experiments show that, compared with MOPSO, the proposed method reduces normalized joint jerk by 35.8% and the bending-safety proxy by 77.0%, while completing all ten repeated trials without controller alarms. Vision-based measurements further show a strong correlation between the proposed proxy and the actual harness bending radius (R2=0.991). Additional routing layouts confirm the applicability of the method to more complex fixture-board configurations. These results demonstrate that the proposed method provides a practical balance among routing efficiency, trajectory smoothness, and process reliability.