Research On Weight Reduction Optimization Of Downward Four-rotor UAV Based On Topology Optimization Method

In this paper,the finite element model of the initial design domain is established according to the performance parameters of commercial small Four-rotor UAV,The working condition of a small Four-rotor UAV base on flight principle was established.In response to mass fraction and relative flexibility changed rate of full design area,an objective function was established to evaluate the flexibility of UAV frame under horizontal flight and ascending flight conditions.Optistruct was used to optimize the shell-shelf integration model and the shell-shelf separation model under different optimization objectives,the optimal topology structure satisfying typical working conditions under multiple constraints was obtained.In order to determine the key structural characteristics of optimization results,the optimization process evolution base on flexibility function constraints and the optimization process evolution base on mass fraction constraints were carried out by gradient adjustment of optimization constraints.The key structural features of the small Four-rotor UAV frame base on this method were obtained,and the optimization results of the two initial design domain structures were compared and analyzed.The mesh results of topology optimization were reconstructed geometrically.Inertial release analysis and vibration characteristic analysis of the model has been optimized were carried out by finite element software.The results of stress,displacement and natural frequency of the shell-shelf integrated model and the shell-shelf separated model under multiple working conditions were obtained.The optimization effect of the initial design domain and the structural feature changes has been optimized were discussed,and the reliability of the optimization method was verified.It provides a feasible idea for the optimal design of a small Four-rotor UAV frame base on the given aerodynamic configuration.