基于改进遗传算法的平流层飞艇定点悬停控制
- 格式:pdf
- 大小:346.20 KB
- 文档页数:6
Vol_35.No.2 Feb,2010 火力与指挥控制 Fire Control&Command Control 第35卷第2期 2010年2月
文章编号:1002—0640(2010)02—0022—06
基于改进遗传算法的平流层飞艇定点悬停控制
王延,周凤岐,周 军,郭建国 (西北工业大学精确制导研究所,西安710072)
摘要:平流层飞艇定点悬停控制是飞艇应用领域的关键技术。该控制问题可以转化为非线性多目标优化问题来求解。 遗传算法是解决现代非线性多目标优化问题的一种重要方法。但是基本遗传算法在解决定点悬停飞艇实际控制同题时,具有 易陷人局部最优解、在遗传进化过程中随机性较强、搜索效率低下及耗时多等缺陷。通过借鉴并行遗传算法、模拟退火算法和 向量评价遗传算法的基本思想,在基本遗传操作中添加切断算子和拼接算子,设计一种改进遗传算法来改善上述缺陷。仿真 结果表明该方法是有效可行的。 关键词:平流层飞艇,定点悬停,遗传算法,多目标优化 中图分类号:V274 文献标识码:A
Stratospheric Airship Spot Hovering Control
based on Improved Genetic Al gorithm
WANG Yan,ZHOU Feng—qi,ZHOU Jun,GUO Jian—guo (Institute for Precision Guidance and Control,Northwestern Polytechnical University,Xi’an 710072。China)
Abstract:The stratosphere airship spot hovering control is the key technology in airship application.
This control problem could be solved by being translated into nonlinear multi—objective optimization problem.Genetic Algorithm is an important modern method in resolving this problem.But in practical airship spot hovering control problem,Simple Genetic Algorithm have some disadvantages such as easily
getting into loca1 optimal solution,serious randomness,inefficient search and serious time cost.In order to overcome these defects,an Improved Genetic Algorithm is proposed.The Improved Genetic Algorithm
uses Parallel Genetic Algorithm,Simulated Annealing Algorithm and Vector Evaluated Genetic Algorithm for reference,and adds cut operator and splice operator in Simple Genetic Operators.The simulation results show that the proposed approach is feasible and effective.
Key words:stratospheric airship,spot hover,genetic algorithm,multi—objective optimization
IntrOductiOn
The stratosphere airship could be used as strategic communication platform, strategic
precautionary platform,missile defense system platform and SO on.The stratosphere airship has
收稿日期:2008—09—11 修回日期:2009—02—27 *基金项目:国家高新技术发展计划基金资助项目 (2007HG020016) 作者简介:王延(1979一),男,甘肃天水人,博士研究 生,研究方向:先进控制理论在导航、制导与控 制中的应用。 great application value as an ideal strategic platform excelling other aircrafts,mainly because
of their heavy load,little energy cost,
noiselessness,long—term spot hovering and quasi—
stationary relative to earth.So,it has become
research focus in recent decade. Stratosphere airship spot hovering control is
the key technology in airship application.This
control problem could be resolved by being
translated into nonlinearity multi—objective optimization problem,and it is always a very
complex problem. Generally, it’S solved by
numerical method.Genetic Algorithm(GA)is
an 王延,等:基于改进遗传算法的平流层飞艇定点悬停控制 (总第35-193) ・23・
important method in resolving modern nonlinearity multi—objective optimization problems[¨.As a self—
adaptive, glqbal—optimal and probabilistic
searching algorithm,the GA’s significant characteristic is that it contains some steps which
are similar to biology heredity and evolution,such
as reproduction,variation,selection,etc。 GA has strong global search ability, furthermore。it doesn’t need differential coefficient
and is independent of model information.
Comparing with common numerical optimization
methods(such as Gradient Method,Newton’s Method, etc), GA avoids i11一condition,
sensitiveness to initial point and local convergence problems.Comparing with theoretical optimization
methods(such as Variational Calculus,Pontryagin
Minimal Principle,etc),GA avoids ignoring much information in model simplification and
decoupling.So it could approximate to real result more exactly.Therefore GA had displayed advantages in a good many applications such as
path programming; numerical optimization, system control and structural optimum distinguish
ever since it was published.However,some
insufficiencies and defects were uncovered.
Aiming at defects of Simple Genetic
Algorithm(SGA)in solving nonlinearity multi— objective optimization problem,such as easily
getting into local optimal solution, serious
randomness,inefficient search and serious time cost..an Improved Genetic Algorithm(IGA)is
proposed.The IGA uses Parallel Genetic Algorithm(PGA),Simulated Annealing Algorithm
and Vector Evaluated Genetic Algorithm(VEGA) for reference,and employs cut operator and splice
operator as complement.
Airship Mathematical Model
The following assumptions are made in order
to simplify the model: its buoyancy; ③Use constant wind field model,and take earth fixed reference frame as inertial reference frame.Its x axis is following latitudinal direction.
According to the airship dynamics model,the airship nonlinear mathematical models in constant wind field is given by Eq.(1),where 一[ , ,
,q,r] is the state vector of dynamic model (1.1);M is mass matrix; , , is respectively the linear velocity component relative to the wind projected on z ,Y ,z axes of body reference frame;g,r is respectively the airship angular rate