Research On Robust Design Optimization Theory And Methods For Engineering Uncertainty

Robust design optimization method, as an effective way to improve product quality and reduce cost, has been paid more attention. The uncertainties existed in practical engineering problem affect the quality stability, so does the product competency. Especially in the complex equipment system, such as wind power system, tunnel shield or plane, if the uncertainties are not considered, then not only economic loss occurs and may even trigger a series of social problems. Therefore, the uncertainties have to be considered in the design stage. However, Existing robust design optimization methods have some limitations, such as small application field and high computational costs. Based on the existent work in literatures the dissertation further develops the robust design theory. The main content of this paper include the following aspects:1) For the problem without sufficient data information on the uncertainties, a novel robust design optimization method using interval analysis is suggested. The original formulation is replaced with the deterministic form at the level of mathematical programming, carried the principle of non-probabilistic method. The method has the advantages that it has less requirements on uncertainty and mathematical, and it is capable of expressing the preference information of the decision maker, resulting in wide suitability.2) For the problem involved with both random and interval uncertain variables, a hybrid probabilistic and non-probabilistic model is suggested for the objective robustness and constraint robustness. The performance robustness is analyzed under mix-uncertainties, and the criterion to build robust model is given. The model provides a new choice for describing the uncertainties accuratedly.3) For the practical engineer robust design problem without explicit mathematical model, a novel robust design optimization method using subspace response surfacing method is suggested. This method is proposed by the rational division of the original response surface approximation space, with the consideration of precision and efficiency. The computational cost is saved due to less sample points for the same fitting precision.4) Aiming at both special working environments and highly reliability requirements of gearbox for wind turbine, the robust design optimization method of gearbox is researched systematically considering the uncertainties based on the proposed robust design theory and methods, in which the transmission system with mathematical model and the supporting system without engineering model are conducted. The robust solution obtained by proposed method ensures optimal design scheme to meet the requirements of various constraints and decreases the sensitivity of the objective to uncertainties, through quantitative analysis of the uncertainty effect to the performance of gearbox.