Aircraft conceptual design optimizations that maximize the performance at a design condition （single-point） may result in designs with unsatisfying off-design performance. To further improve aircraft efficiency unde...Aircraft conceptual design optimizations that maximize the performance at a design condition （single-point） may result in designs with unsatisfying off-design performance. To further improve aircraft efficiency under actual flight operations, there is a need to consider multiple flight conditions （multipoint） in aircraft conceptual design and optimization. A new strategy for multipoint optimizations in aircraft conceptual design is proposed in this paper. A wide-body aircraft is taken as an example for both single-point and multipoint optimizations with the objective of maximizing the specific hourly productivity. Boeing 787-8 flight data was used in the multipoint opti- mization to reflect the true objective function. The results show that the optimal design from the multipoint optimization has a 7.72% total specific hourly productivity increase of entire flight missions compared with that of the baseline aircraft, while the increase in the total specific hourly productivity from the single-point optimal design is only 5.73%. The differences between the results of single-point and multipoint optimizations indicate that there is a good option to further improve aircraft efficiency by considering actual flight conditions in aircraft conceptual design and optimization.展开更多
To expand mission capabilities needed without a proportional increase in cost or risk for exploration of the solar system,the multiple objective trajectory using low-thrust propulsion and gravity-assist technique is c...To expand mission capabilities needed without a proportional increase in cost or risk for exploration of the solar system,the multiple objective trajectory using low-thrust propulsion and gravity-assist technique is considered.However,low-thrust,gravity-assist trajectories pose significant optimization challenges because of their large design space.Here,the planets are selected as primal scientific mission goals,while the asteroids are selected as secondary scientific mission goals,and a global trajectory optimization problem is introduced and formulated.This multi-objective decision making process is transformed into a bi-level programming problem,where the targets like planets with small subsamples but high weight are optimized in up level,and targets like asteroids with large subsamples but low weight are optimized in down level.Then,the selected solutions for bi-level programming are optimized thanks to a cooperative Differential Evolution(DE) algorithm that is developed from the original DE algorithm;in addition,an sequential quadratic programming(SQP) method is used in low-thrust optimization.This solution approach is successfully applied to the simulation case of the multi-objective trajectory design problem.The results obtained are presented and discussed.展开更多
基金supported by the Fundamental Research Funds for Central Universities(NUAA NS2016010)
文摘Aircraft conceptual design optimizations that maximize the performance at a design condition （single-point） may result in designs with unsatisfying off-design performance. To further improve aircraft efficiency under actual flight operations, there is a need to consider multiple flight conditions （multipoint） in aircraft conceptual design and optimization. A new strategy for multipoint optimizations in aircraft conceptual design is proposed in this paper. A wide-body aircraft is taken as an example for both single-point and multipoint optimizations with the objective of maximizing the specific hourly productivity. Boeing 787-8 flight data was used in the multipoint opti- mization to reflect the true objective function. The results show that the optimal design from the multipoint optimization has a 7.72% total specific hourly productivity increase of entire flight missions compared with that of the baseline aircraft, while the increase in the total specific hourly productivity from the single-point optimal design is only 5.73%. The differences between the results of single-point and multipoint optimizations indicate that there is a good option to further improve aircraft efficiency by considering actual flight conditions in aircraft conceptual design and optimization.
基金supported by the Open Research Foundation of Science and Technology on Aerospace Flight Dynamics Laboratory of China (Grant No. 2012afdl005)
文摘To expand mission capabilities needed without a proportional increase in cost or risk for exploration of the solar system,the multiple objective trajectory using low-thrust propulsion and gravity-assist technique is considered.However,low-thrust,gravity-assist trajectories pose significant optimization challenges because of their large design space.Here,the planets are selected as primal scientific mission goals,while the asteroids are selected as secondary scientific mission goals,and a global trajectory optimization problem is introduced and formulated.This multi-objective decision making process is transformed into a bi-level programming problem,where the targets like planets with small subsamples but high weight are optimized in up level,and targets like asteroids with large subsamples but low weight are optimized in down level.Then,the selected solutions for bi-level programming are optimized thanks to a cooperative Differential Evolution(DE) algorithm that is developed from the original DE algorithm;in addition,an sequential quadratic programming(SQP) method is used in low-thrust optimization.This solution approach is successfully applied to the simulation case of the multi-objective trajectory design problem.The results obtained are presented and discussed.
