An Optimization Method for Frame Structure of Unmanned Helicopter Based on Empirical Optimization and Downhill Simplex Method

The frame structure optimization of unmanned helicopter is an important way to reduce the weight of the helicopter under the premise of meeting the strength requirements. Excellent helicopter frame structure optimization method can not only obtain excellent weight optimization results, but also save computing resources. In this paper, a global optimization combination method using empirical optimization and Downhill simplex method is proposed for optimization. In the early stage of optimization, the stress states under different overload conditions are analyzed and summarized. Based on experience, the thicknesses of the parts with larger stress are increased appropriately, and the thicknesses of the parts with smaller stress are reduced appropriately. This method is applied during the early design stage, and reduces the structural weight rapidly based on the designer's experience. In the later stage of optimization, the optimization algorithm is used for global optimization. In this way, the parametric modeling method of finite element software is used to quickly and automatically establish the model and solve the problem. The results are fed back to the optimization algorithm by giving the value range of each parameter and taking the lightest total weight of the structure as the optimization objective. The optimization results show that this method achieves higher weight loss goals with higher efficiency than other methods.