Task-Constraint-Embedded Lightweight Structural Overall Design and Validation of UAVs for Air-Ground Collaborative Missions

Air-ground collaborative missions impose coupled constraints on unmanned aerial vehicles (UAVs), including restricted platform envelopes, rapid payload reconfiguration, transient interface impacts, and center of gravity (CG) shifts. Conventional serial design workflows fixing overall layout before local lightweighting are insufficient to satisfy structural mass reduction, interface safety, and attitude recovery requirements simultaneously. This study proposes a task-constraint-embedded multi-level lightweight structural design method for UAVs operating with ground mobile platforms. The layout-evaluation framework incorporates ground-platform envelope limits, UAV payload distribution, CG migration, and attitude-stability requirements through a hierarchical screening and score-based selection process. Mass reduction rate, CG shift, and layout compactness are used as the main layout-evaluation indicators, and a feasible layout is selected for subsequent structural zoning and verification. Subsequently, the airframe is partitioned into load-bearing, non-load-bearing, and interface zones, for which main-skeleton topology optimization, honeycomb sandwich lightweighting, and local interface reinforcement are applied, respectively. The optimized prototype is validated through finite-element simulation, interface-impact testing, and full-scale flight trials. Relative to the defined traditional baseline, the selected design reduces the whole-airframe mass by 19.2%, limits the payload-switching-induced CG shift to 2.80 cm, and shortens the attitude-settling time by 39.7%. The main verification indicators show simulation-test deviations below 4.2% for the selected layout and representative verification cases. These results indicate that embedding task-specific constraints into the overall layout-evaluation stage can improve the balance among lightweighting, interface-load resistance, and dynamic-stability requirements.