Research On Helicopter Conceptual/Preliminary Multidisciplinary Design Optimization

The application of Multidisciplinary Design Optimization (MDO) to helicopter conceptual/preliminary design is researched in this thesis.In recent years, the aircraft design is transformed from the traditional "design for performance" to the modern "design for affordability and quality". A wide range of applications of multi disciplinary design optimization method to aircraft design greatly reduces the whole aircraft life cycle cost and development risk and shortens the design cycle, as well as improves design quality and aircraft system effectiveness. Since helicopter conceptual/preliminary design involves aerodynamics, flight mechanics, dynamics, weight, economy and many other disciplines, all disciplines are coupled and influenced each other, so the character of helicopter design is a typical problem of MDO and its application in the helicopter design is inevitable development direction. This thesis focuses on the key technologies of the multidisciplinary design optimization at the application of helicopter design. By integrated a number of helicopter design-related disciplines, the overall helicopter multidisciplinary design optimization system is initially established to provide theoretical and technical reserves for our country new helicopter development.Firstly according to the characteristics of helicopter conceptual/preliminary design, the helicopter conceptual/preliminary multidisciplinary design optimization framework is set up, including the conceptual design stage to initially select the helicopter overall parameters and preliminary design phase to optimize the design parameters. A conceptual design approach based on statistical analysis for tractical utility transport helicopter overall parameters initial selection is presented in this thesis.Because the helicopter overall parameters and layout parameters effect on the helicopter stability and control, the model of helicopter stability and control analysis is set up in this thesis. Using optimization design method to select the appropriate helicopter overall parameters, the helicopter stability and control are improved. While comparing with the classic numerical optimization algorithm, intelligent optimization algorithms and hybrid optimization algorithm, the hybrid optimization algorithm is more suitable for the solution of the helicopter stability and control optimization model.In order to improve the efficiency of the helicopter stability and control optimization model, the helicopter stability and control optimization design based on the surrogate model is studied. The different types of the surrogate models and experimental design methods, as well as and the sizes of the sample point set established the surrogate model effected on the accurate are compared. The advantages and disadvantages of the direct and iterative optimization method based on surrogate model are analyzed. The hybrid algorithm/model optimization method is presented in this thesis to improve the optimization efficiency.Based on the establishment of the helicopter flight performance, weight, stability and control and economic analysis model, the helicopter conceptual/preliminary multidisciplinary design optimization model is set up.For the multi-objective characteristic of the helicopter conceptual/preliminary multidisciplinary design optimization model and the collaborative optimization bad convergence and large computation, the Distributed Multi-objective Collaborative Optimization (DMOCO) method is presented in this thesis. The mathematic experimental results show the feasibility and effectiveness of the method. Finally the overall evaluation criteria for the affordable transportation helicopter is set up. Using the iSIGHT software integrate helicopter various disciplines analytical procedures, the helicopter conceptual/preliminary multidisciplinary design optimization systems based on multidisciplinary feasibility method and DMOCO method are established. The UH-60A helicopter conceptual/preliminary multidisciplinary design optimization is investigated. The results show that the overall helicopter multidisciplinary design optimization system can be effectively applied to optimize the helicopter design parameters, able to take advantage of coordination among various disciplines effectiveness and select the high-performance low-cost design scheme to meet the design requirements.