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基于单纯形局部搜索的自适应差分进化算法 被引量:4
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作者 李会荣 《海南大学学报(自然科学版)》 CAS 2013年第2期143-148,共6页
针对标准的差分进化(DE)算法在高维复杂的函数优化中易早熟收敛,进而导致搜索精度低甚至优化失败的问题,提出一种基于单纯形局部搜索的自适应的差分进化算法(SSADE).将DE算法的快速全局搜索能力与单纯形的强局部寻优能力有机结合起来,... 针对标准的差分进化(DE)算法在高维复杂的函数优化中易早熟收敛,进而导致搜索精度低甚至优化失败的问题,提出一种基于单纯形局部搜索的自适应的差分进化算法(SSADE).将DE算法的快速全局搜索能力与单纯形的强局部寻优能力有机结合起来,进一步提高了解的精度.参数自适应变化有效地维持了种群的多样性,自适应的变异策略扩大了个体的搜索范围,增强了算法寻优效果,仿真实验验证了新混合算法的有效性. 展开更多
关键词 差分进化 单纯形局部搜索 自适应变异
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Optimal four-impulse rendezvous between coplanar elliptical orbits 被引量:6
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作者 WANG JianXia BAOYIN HeXi +1 位作者 LI JunFeng SUN FuChun 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第4期792-802,共11页
Rendezvous in circular or near circular orbits has been investigated in great detail, while rendezvous in arbitrary eccentricity elliptical orbits is not sufficiently explored. Among the various optimization methods p... Rendezvous in circular or near circular orbits has been investigated in great detail, while rendezvous in arbitrary eccentricity elliptical orbits is not sufficiently explored. Among the various optimization methods proposed for fuel optimal orbital rendezvous, Lawden's primer vector theory is favored by many researchers with its clear physical concept and simplicity in solu- tion. Prussing has applied the primer vector optimization theory to minimum-fuel, multiple-impulse, time-fixed orbital ren- dezvous in a near circular orbit and achieved great success. Extending Prussing's work, this paper will employ the primer vec- tor theory to study trajectory optimization problems of arbitrary eccentricity elliptical orbit rendezvous. Based on linearized equations of relative motion on elliptical reference orbit (referred to as T-H equations), the primer vector theory is used to deal with time-fixed multiple-impulse optimal rendezvous between two coplanar, coaxial elliptical orbits with arbitrary large ec- centricity. A parameter adjustment method is developed for the prime vector to satisfy the Lawden's necessary condition for the optimal solution. Finally, the optimal multiple-impulse rendezvous solution including the time, direction and magnitudes of the impulse is obtained by solving the two-point boundary value problem. The rendezvous error of the linearized equation is also analyzed. The simulation results confirmed the analyzed results that the rendezvous error is small for the small eccentric- ity case and is large for the higher eccentricity. For better rendezvous accuracy of high eccentricity orbits, a combined method of multiplier penalty function with the simplex search method is used for local optimization. The simplex search method is sensitive to the initial values of optimization variables, but the simulation results show that initial values with the primer vector theory, and the local optimization algorithm can improve the rendezvous accuracy effectively with fast convergence, because the optimal results obtained by the primer vector theory are already very close to the actual optimal solution. 展开更多
关键词 If the initial values are taken randomly it is difficult to converge to the optimal solution. elliptical orbit rendezvous primer vector fuel optimal
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