Research On Uncertainty Multi-Objective Multidisciplinary Design Optimization Theory And Its Application To Aircraft Conceptual Design

Aircraft conceptual design is a typical multi-objective multidisciplinary problem system and exiets many uncertain factors in the design problem. To enhance aircraft design quality, the theory and its application of Uncrtainty Multi-Objective Multidisciplinary Design Optimization (UMOMDO) is systematically studied in this paper. The research is especially focused on the search strategy of the design space and the MDO procedure, based on which a multidisciplinary design optimization environment is set up as a tool for aircraft conceptual design.Some UMOMDO theories are discussed as follows:Firstly, the fundamental theories of UMOMDO including multi-objective optimization theory and uncertainty design theory are studied, which establish the technical foundation for UMOMDO.Secondly, the search strategy of the design space is studied. A novel intelligence optimization, Plant Growth Optimization (PGO), is proposed and three classical test problems are adopted to test the performance of PGO. The results show that it is very effective to get global optimum solution which benefits from its search mechanism. Based on PGO, with niches technique and mutation operator to improve the diversity of nondominated set, a novel multi-objective algorithms Multi-Objective Plant Growth Optimization (MOPGO) is proposed. The approach is validated using a set of test problems. The simulation results show that the approach possesses high searching efficiency and can efficiently find multiple Pareto optimal solutions. Aimed at the computation cost problem of the aforementioned uncertainty hybrid intelligence algorithm, on the combination of neural network, sequential approximation modeling method and PGO, a novel uncertainty algorithm Uncertainty Hybrid Plant Growth Optimization (UHPGO) is proposed to reduce the computation cost.Finally, MDO procedure is studied. An improved MDO procedure for BLISS 2000 (Bi-Level Integrated System Synthesis 2000) is proposed and two novel multi-objective MDO procedures including multi-objective Pareto BLISS 2000 and multi-objective BLISS 2000 based on expected value for multidisciplinary design are proposed through assigning object to subsystem optimization. Also based on BLISS 2000, further integrating uncertainty design and optimization method, an Uncertainty Bi-Level Integrated System Synthesis 2000 (UBLISS) is put forward.UBLISS can efficiently organize the process of complex system uncertainty design optimization,and mitigate the calculation difficulties, so as to improve the efficiency of uncertainty optimization.Some UMOMDO applications are discussed as follows:Firstly, an airplane conceptual design is chosen as the study object. According to the requirement, a system scheme is primarily designed. The disciplinary models of the airplane conceptual design are proposed, and uncertainties of the models are analyzed and modeled. Uncertainty Multi-Objective Bi-Level Pareto Integrated System Synthesis (UMOPBLISS) is propsed to solve the problem which is lack of design information. UMOPBLISS is adopted to integrate and resolve the uncertainty multiobjective multidisciplinary design optimization problem of the airplane conceptual design. The optimization result confirms the feasibility and validity of UMOPBLISS. More, Uncertainty Expected Goal based Multi-Objective Bi-Level Pareto Integrated System Synthesis (UEGMOBLISS) is proposed to solve the multiobjective problems with expected goal and adopted to integrate and resolve the airplane conceptual design problem. The optimization result confirs the feasibility and validity of UEGMOBLISS, which offers a robust and reliable optimum system design scheme of the airplane.Finally, a Multidisciplinary Integrated Design Optimization System (MIDOS) is established for MDO framework. An Airplane Conceptual Multidisciplinary Design Environment is set up for the airplane conceptual design.To sum up, UMOMDO theory framework is formulated and applied to the airplane conceptual design. It is the continuation of the MDO theory.and establishes a good foundation for improvement of aircraft conceptual design.