CN101515311A - Method for determining united optimization design parameter of satellite thermal insulating layer and radiating surface system - Google Patents

Abstract

The invention applies chaos genetic algorithm (CGA) to make united optimization design for the area of a radiating surface and the thickness of a thermal insulating layer of nano-satellite, so as to reach the temperature requirement ensuring the nano-satellite to work normally better. According to one aspect of the invention, a method for determining united optimization design parameter of satellite thermal insulating layer and radiating surface is characterized by comprising: the satellite is divided into a plurality of temperature set total units; a group of design parameter (Fr and delta s) with minimum value of one united optimization design objective function (f (Fr and delta s)) of the thermal insulating layer and the radiating surface is determined; the optimized objective function (f (Fr and delta s)) is corresponding to the temperature of each of the temperature set total units and has the positive correlation with the deviation of the preset optimum working temperature, including searching the optimization within the whole feasible solution range of the optimized objective function (f (Fr and delta s)), thereby determining the optimization design parameter which is better to satisfy the comprehensive evaluating indicator of the thermal insulating layer and the radiating surface.

Description

The united optimization design parameter of the system of satellite thermal insulating layer and radiating surface is determined method

Technical field

The present invention relates to a kind of based on Chaos Genetic Algorithm (Chaos Genetic Algorithm is hereinafter to be referred as CGA) receive satellite thermal insulating layer thickness and radiating surface area combined optimization method for designing, belong to the space science technical field.

Background technology

(1) receives the generation and the application of satellite

The satellite of receiving is proposed in a research report in 1993 first by US Airways space flight company (Aerospace) the earliest, it be microelectromechanicpositioning integral system (MEMS the is called for short micromechanics) technology of getting up with development in recent years and the ASIM of forming by several MEMS (ASIM) satellite for basic a kind of novel concept.The satellite of receiving has gathered new technology, new material, new technologies such as microelectron-mechanical, lightweight composite materials and hyperfine machining, and its quality is between 1～10kg, and functional density greatly improves.

The satellite of receiving can realize that single cheap moonlet finishes the individual event task fast, can form constellation with numerous low-cost and high-performance moonlets again, finish complicated space mission.The satellite of receiving has wide application prospect at aspects such as global personal communication, mobile communication, earth environment monitoring, scientific research, poster presentation, planetary detection, education and military affairs.Receive the development of satellite, a major transformation of fermenting space industry, the satellite of receiving will occupy consequence in the aerospace system in future.The principal feature of satellite received has: the integrated design of satellite and integrated level height, light weight; Viability is strong, manufacturing and launching costs are cheap.Be one of important directions of current international spationautics development, embodied the development trend of spacecraft microminiaturization.

(2) traditional spacecraft thermal design method

Along with the continuous miniaturization of satellite, more and more higher requirement has also been proposed for himself thermal management capabilities.Spacecraft temperature control can be adopted passive heat control technology and active heat control technology, serves as that initiatively the thermal control method is auxilliary with the passive heat control method generally.The passive heat control method is determined corresponding thermal control hardware according to the design feature of spacecraft and with the heat delivered mode of surrounding environment or other member, with this rationally arrange between celestial body surface and the space environment and celestial body interior instrument parts between the heat transmission, each part temperatures that makes spacecraft is all in the temperature range of trouble free service.The passive heat control method possesses skills simply, good reliability, and the advantage of long service life is the important means of spacecraft thermal control.The passive thermal control assembly of common spacecraft has: thermal control coating, multilayer insulation assembly, heat pipe, phase-change heat-exchange device.The purpose of nano-satellite hot control design is by rational thermal design method and heat control means, provides each subsystem instrument and equipment operate as normal of satellite useful load and satellite platform required environment temperature, guarantees to receive satellite all devices operate as normal simultaneously.

The spacecraft thermal design that the thermal control designer is carried out mainly realizes (as shown in Figure 1) by following steps: (1) carries out heat analysis to spacecraft, sets up its hot mathematical model according to spacecraft in the heat budget equilibrium relation of space; (2) calculate the space hot-fluid that arrives the spacecraft surface, analyze and the design radiating surface; (3) rule of thumb each parts and spacecraft structure are adopted the thermal control measure, judge the coldest and thermal condition that may occur then; (4) determining to carry out CALCULATION OF THERMAL behind the boundary condition, in allowed limits whether the temperature of judging each several part, then to adjust the corresponding thermal control measure of this part if any inappropriate part, carry out CALCULATION OF THERMAL again, until the temperature of all parts all in suitable scope.This method for designing needs calculating and checking repeatedly, and bigger for the calculated amount that system-level global design spent, resulting final design result also might not be an optimal result; What at first satisfy during thermal design is the thermal design demand of parts, can not guarantee the whole structure optimum.In order to reach the total optimization effect, be necessary the heat control system parts of spacecraft are carried out the combined optimization design.

(3) common Optimization Design

Ask the method for optimization problem optimum solution or approximate optimal solution to mainly contain: enumerative technique, heuritic approach and searching algorithm.These three kinds of methods respectively have the relative merits of oneself: enumerative technique can enumerate all feasible solutions in the feasible solution set, obtain accurate optimum solution, but its efficient is lower, and is very consuming time; Heuritic approach is sought optimum solution by seeking a kind of heuristic rule that produces feasible solution, though efficient is higher, heuristic rule does not have versatility; Searching algorithm is by carrying out optimum solution or the approximate optimal solution that search operation is sought problem in the subclass of feasible solution set, it can reach balance preferably with finding the solution in the quality of approximate solution on the efficient.

Genetic algorithm (Genetic Algorithm, note by abridging be GA) is a kind of random search algorithm with global optimization ability that is proposed by professor J.Holland.GA algorithm strong robustness is a kind of adaptable global optimum searching algorithm.In the research of taking all factors into consideration multinomial evaluation index problem, can find the Pareto of optimization problem to separate.But basic genetic algorithmic also has inevitable shortcoming: as precocious phenomenon, be absorbed in local optimum easily, find optimum solution need carry out a large amount of iterative computation.Bring into play its advantage for the shortcoming that overcomes genetic algorithm, some researchists have introduced genetic algorithm with chaos thought, have formed Chaos Genetic Algorithm (CGA).Chaos is defined as by Elizabeth Bradley: it is a kind of complexity unpredictable of a definite physical system, and seems behavior at random.According to the characteristic of chaotic motion, chaotic motion can all states in traversal search space, and each state only occurs once.CGA searches for according to the rule of chaotic motion, can travel through any point in the solution space, therefore compares with other random optimization algorithm, and it can jump out local optimum at an easy rate, avoids precocious phenomenon.

Summary of the invention

The present invention uses Chaos Genetic Algorithm (CGA) to carry out the combined optimization design to receiving the radiating surface area of satellite and thermofin thickness, receives the temperature requirement of the better operate as normal of satellite to reach.

According to an aspect of the present invention, provide a kind of satellite thermal insulating layer and radiating surface united optimization design parameter to determine method, it is characterized in that comprising:

Described satellite is divided into a plurality of temperature set total units,

Determine to make a combined optimization design object function (f (F of described thermofin and radiating surface _r, δ _s)) the value minimum one group of design parameter (F _r, δ _s), described optimization aim function (f (F _r, δ _s)) with the deviation positive correlation of the predetermined optimum working temperature of relative this temperature set total units of temperature of each temperature set total units in described a plurality of temperature set total units, comprising:

At described optimization aim function (f (F _r, δ _s)) whole feasible solution space search for optimizing, thereby determine preferably to satisfy the optimal design parameter of the comprehensive evaluation index of described thermofin and radiating surface.

Figure of description

Fig. 1 has shown a kind of traditional satellite thermal design flow process.

Fig. 2 has shown and has according to an embodiment of the inventionly received satellite thermal insulating layer and radiating surface combined optimization design cycle based on Chaos Genetic Algorithm.

Fig. 3 is used for explanation and receives satellite in the rail thermal environment.

Fig. 4 has illustrated to show the satellite structure of receiving that can use method according to an embodiment of the invention.

Fig. 5 has shown that initial value is 0.2 logistic chaos sequence.

Fig. 6 has shown satellite thermal insulating layer thickness and the radiating surface area evolution curve received according to an embodiment of the invention.

Embodiment

The object of the present invention is to provide a kind of satellite passive heat management system Optimization Design based on Chaos Genetic Algorithm, to solve be scattered about like the stars optimal design problem in hot side area and the thermofin thickness co-design of prior art centre halfback, satisfy the temperature requirement of satellite operate as normal better.

According to one embodiment of present invention, provide based on Chaos Genetic Algorithm receive satellite radiating surface area and thermofin thickness optimization method for designing, to solve traditional satellite passive heat management system method for designing problem consuming time and inefficient of receiving; Wherein, the nano-satellite hot system is being carried out determining the objective function of optimization design function on the basis of dynamic analysis according to thermodynamics knowledge use lumped-parameter method; For solving the easily precocious problem that is absorbed in local optimum easily that reaches of traditional genetic algorithm, the utilization Chaos Genetic Algorithm is sought the nano-satellite hot management system parameter combinations that makes the target function value minimum in the solution space of multidimensional parameter value, to obtain making the designed model parameter system of receiving the passive cooling system best performance of satellite.Technical solution of the present invention is:

A kind ofly receive satellite radiating surface area and thermofin thickness optimization method for designing to solve traditional satellite passive heat management system method for designing problem consuming time and inefficient of receiving based on Chaos Genetic Algorithm; According to thermodynamics knowledge use lumped-parameter method the nano-satellite hot system is carried out dynamic analysis, determine the objective function of optimization design function.For solving the easily precocious problem that is absorbed in local optimum easily that reaches of traditional genetic algorithm, the utilization Chaos Genetic Algorithm is sought the nano-satellite hot management system parameter combinations that makes the target function value minimum in the solution space of multidimensional parameter value, to obtain making the designed model parameter system of receiving the passive cooling system best performance of satellite.

Fig. 4 has shown the layout of receiving satellite that can use method according to an embodiment of the invention.In Fig. 4, label 41 represents to receive the satellite thermally insulating housing, and 42 represent to receive the satellite radiating surface, the 43 high heat conducting elements of representing to receive between satellite instrument cabin and the radiating surface, and 44 represent to receive the satellite instrument cabin.

Fig. 2 has shown an embodiment of method of the present invention, and it mainly comprises the steps (the frame of broken lines middle part is divided into the Chaos Genetic Algorithm flow process):

(1) sets up and to carry out combined optimization and design mathematical model receiving satellite thermal insulating layer thickness and radiating surface area.

A. will conclude satellite and be divided into three temperature set total units according to receiving the work characteristics of satellite each several part: receive inside satellite thermal environment, shell and radiating surface, its medial temperature is respectively T _i, T _s, T _r

B. according to orbit altitude, calculate to arrive and receive the space heat flux Q of satellite shell and radiating surface _s, Q _r, receive satellite shell and radiating surface to arrange in the heat radiation mode and loose to the heat in space and the heating power Q of inside satellite instrument and equipment of receiving, and the coldest thermal condition of working.

C. set up nano-satellite hot system thermal balance equation according to the energy budget equilibrium relation of receiving between the satellite three big temperature set total units.

Optimization aim is chosen as: make and receive the working temperature of satellite three big temperature set total units all near optimum working temperature; Decision variable is thermofin thickness and radiating surface area.

(2) the utilization Chaos Genetic Algorithm is optimized, and adjusts program running parameter, seeks the Pareto optimum solution that Chaos Genetic Algorithm is optimized, and specifically comprises:

A. generate chaos sequence according to chaotic maps.Chaos Variable is normally produced by nonlinear iteration, and wherein the logistic mapping is exactly one of foremost chaotic maps, and it is the one dimension unimodal map, suc as formula (2):

x _k+1＝μx _k(1.0-x _k) (2)

μ is a controlled variable in the formula, 0.0＜x _k＜1.0, $x_k\∉\left\{\mathrm{0.25,0.5,0.75}\right\},$ When μ=4, the system shown in the formula (2) produces chaos sequence.Even if initializaing variable x ₀ ⁽¹⁾, x ₁ ⁽¹⁾..., x _n ⁽¹⁾Minute differences is only arranged, the Chaos Variable x of generation ₀ ^(k), x ₁ ^(k)..., x _n ^(k)Also have than big-difference, and their stochastic distribution, have and do not have repeatability.

B. generate initial population.From the P group chaos sequence that generates, get P group Chaos Variable and be mapped to and receive the value space of satellite thermal insulating layer thickness and radiating surface area, generate individual chromosomal, obtain the phenotype of individuality;

C. determine ideal adaptation degree evaluation method.Calculate each individual pairing target function value M (X), determine its fitness function value F (X) by transformation rule;

D. carry out selection operation.Simulate the operation of gambling dish with the random number of logistic sequence generation 0～1, according to selecting Probability p _s, according to the principle of " survival of the fittest " from t for selecting the higher individuality of fitness the P of colony (t) as the parent individuality, carry out the genetic manipulation of P (t+1) for colony;

E. carry out interlace operation.At first to the pairing in twos at random of parent individuality, according to crossover probability p _c, judge whether individuality intersects, generate the point of crossing if intersect then to shine upon with the random number of logistic sequence generation 0 ~ 1, adopt even arithmetic to intersect and generate individuality newly;

F. carry out mutation operation.According to the variation Probability p _m, judge whether individuality makes a variation, if then generating 0～1 random number mapping by the logistic sequence, variation generates change point, adopt even variation mode to change genic value on individual certain some locus, generate new individuality;

G. repeat b, c, d, e, f is until satisfying the loop ends condition.

(3) when satisfying the loop ends condition, end loop output is optimized the nano-satellite hot system optimal that obtains and is separated.

Nano-satellite hot control assembly and principle of work

The passive heat control method is determined corresponding thermal control hardware according to the design feature of spacecraft and with the heat delivered mode of surrounding environment or other member, adjust the heat exchanging process of space flight inside and outside it with this, reach make spacecraft each part temperatures all in the temperature range of trouble free service.The passive heat control method possesses skills simply, good reliability, and the advantage of long service life is the important means of spacecraft thermal control.Serve as that initiatively the thermal control method is auxilliary generally in the spacecraft heat control with the passive heat control method.The passive thermal control assembly of common spacecraft has: thermal control coating, multilayer insulation assembly, heat pipe, phase-change heat-exchange device.

Receiving in the passive heat control system of satellite, the thermofin that radiating surface and multilayer insulation material are formed is its important ingredient.Receive satellite in orbit during multilayer insulation material mainly to act on be the thermal loss that reduces satellite equipment equipment, what its utilized is the heat insulation principle (as shown in Figure 3) of reflection multilayer screen.The equivalent radiance of multilayer insulation assembly is

ε _eq1＝ε/[(N+1)(2-ε)]

Wherein, ε is the radiance of individual layer thermoscreen, and N is the number of plies of thermoscreen.The radiating surface of satellite received is positioned at celestial body side back to the sun in orbit the time, carries out heat interchange with thermal-radiating mode and space outerpace, is to receive the main path that the unnecessary heat of inside satellite looses to cosmic space row.

The nano-satellite hot environment

The thermoanalytical method of spacecraft of carrying out commonly used is a lumped-parameter method, its principle is: at first the temperature feature according to each parts of spacecraft and instrument and equipment is divided into different temperature set total units with it, sets up mathematical model according to the heat delivered between each temperature set total units and equilibrium relation then and carries out heat analysis.According to receiving the temperature feature difference of each parts of satellite, be three temperature set total units with the nano-satellite hot system divides: receive environment in the satellite cabin, medial temperature is T _iThe satellite of receiving is installed the radiating surface of radiator, and medial temperature is T _rWhat the multilayer insulation assembly was installed receives the satellite shell, and medial temperature is T _s

The heat delivered mode of receiving between each temperature set total units of satellite is: the exchange heat in the cabin between environment and the radiator is mainly heat exchange pattern, the heat transfer element that relies on high thermal conductivity with unnecessary heat dissipation to cold black cosmic space; The heat part that instrument and equipment distributes in the cabin will be omitted space outerpace by the multilayer insulation shell, is referred to as leaking heat, is the main exchange heat approach between environment and thermally insulating housing in the cabin.Under the situation that multilayer insulation component layer density is fixed, the radiation shield number of plies of multilayer insulation assembly is many more, and insulating assembly thickness is big more, and its equivalent radiance is just more little, and corresponding its leaking heat is just more little, and heat insulation effect is good more; Spaceborne radiator and satellite shell coating all will receive space heat flux from different directions, simultaneously also in thermal-radiating mode to the space outerpace distribute heat.

The present invention uses Chaos Genetic Algorithm to receiving satellite thermal insulating layer and radiating surface combined optimization method for designing

According to one embodiment of present invention, proposed a kind ofly to receive satellite thermal insulating layer thickness and radiating surface area combined optimization method based on Chaos Genetic Algorithm.According to receiving the heat budget balance rule of three temperature set total units of satellite, determine the balance equation when system reaches stable state, obtain receiving the explicit representation form of three temperature set total units temperature of satellite by this equation.The random number that chaos sequence is generated according to the coding rule of genetic algorithm is encoded and is mapped to solution space and generates initial population, and initial population is evolved according to Chaos Genetic Algorithm evolution rule.For preventing that optimum individual from being destroyed by the genetic algorithm operator, adopt optimum conversation strategy that each is preserved and be genetic to by force the next generation for the optimum individual that generates.If genetic algorithm is described as a homogeneous Markov chain Pt={P (t), t 〉=0} carries out the convergence analysis as can be known to it, and the probability that the genetic algorithm of use optimized individual conversation strategy can converge on optimum solution is 1.Thereby, the adjustment algorithm parameter, search in whole feasible solution space, can optimizing obtain making the pareto of each lump cell temperature comprehensive evaluation index optimum of satellite to separate at last, thereby preferably be satisfied the optimal design parameter of each lump cell temperature comprehensive evaluation index of satellite.

The present invention compares and has the following advantages with the existing satellite passive heat system design technology of receiving:

(1) provides a kind of combined optimization method for designing and calculation procedure of receiving satellite thermal insulating layer and radiating surface, can make things convenient for exactly and to realize receiving the combined optimization design of satellite passive heat design system, reduced the traditional hot design to each thermal control parts separately design computational complexity and verify modification repeatedly;

(2) the utilization Chaos Genetic Algorithm is carried out combined optimization and is designed receiving satellite thermal insulating layer thickness and radiating surface area, can obtain good design result by less calculation cost.Not only can be optimized design, and can optimize the optimal design result under do not coexisted design criteria and the strategy, thereby the design criteria and the layout strategy of more realistic demand are determined in contrast at specific design criteria and layout strategy.

(3) utilization computer programming calculation, can be easily to the adjustment of making amendment of optimal design strategy or design criteria; Genetic algorithm parameter is adjusted, and realizes simple, with low cost.

Introduce genetic algorithm below in conjunction with drawings and Examples and receiving the concrete utilization in area-optimized of satellite thermal insulating layer thickness and radiating surface.The satellite of receiving among the embodiment is a satellite in Sun-synchronous orbit, and the inside satellite instrument heating power of receiving changes in the 4W-50W scope, the low α of radiating surface surface spraying _r/ ε _Eq3Coating material, the celestial body remaining surface sprays high α _s/ ε _Eq2Coating material.α wherein _r, α _sIt is respectively the absorptivity of corresponding coating material.The satellite of receiving is worked on geostationary orbit, accepts the direction of sun power and fixes.

(1) adopting lumped-parameter method will receive satellite is divided into three temperature set total units and carries out heat analysis

A. set up and receive satellite three big temperature set total units thermal balance equation

The utilization lumped-parameter method is regarded nano-satellite hot control system as three big temperature set total units: comprise receive the satellite instrument cabin receive inside satellite thermal environment, shell and radiating surface, its medial temperature is respectively T _i, T _s, T _rReceive that unnecessary heat mainly looses to space outerpace by radiating surface row in heat conducting mode in the inside satellite thermal environment, the small part heat is arranged diffusing by the leakage heat of thermofin; Radiating surface and thermally insulating housing coating receive space heat flux, simultaneously in the heat radiation mode to space heat elimination.According to law of conservation of energy, the energy that flows to a unit equals to flow out the energy of this unit, receives the thermal balance equation of satellite and environment in the time of can reaching stable state suc as formula (3)-Shi (5):

$0=Q_i-F_s{\mathrm{\σ\ϵ}}_{\mathrm{eq}1}(T_i^4-T_s^4)-K_{\mathrm{ir}}{F}_r(T_i-T_r)---\left(3\right)$

$0=Q_s+F_s{\mathrm{\σ\ϵ}}_{\mathrm{eq}1}(T_i^4-T_s^4)-F_s{\mathrm{\σ\ϵ}}_{\mathrm{eq}2}{T}_s^4---\left(4\right)$

$0=Q_r+K_{\mathrm{ir}}{F}_r(T_i-T_r)-F_r{\mathrm{\σ\ϵ}}_{\mathrm{eq}3}{T}_r^4---\left(5\right)$

I wherein, r, s are respectively the subscripts of interior instrument, thermofin, radiating surface, F represents surface area; σ is Si Difen-Boltzmann constant; ε _Eq1, ε _Eq2, ε _Eq3Be respectively the radiance on thermofin, coating material and radiating surface surface.Q _iFor receiving the heating power of inside satellite heat dissipation element, Q _s, Q _rThen be respectively to receive satellite thermal insulating layer and radiating surface from heat that space outerpace absorbed.Formula (3)-Shi (5) is expressed as about T _i, T _r, T _sFunction suc as formula (6):

$\left\{\begin{array}{c}{f}_1(T_i,T_s,T_r)=0\\ f_2(T_i,T_s,T_r)=0\\ f_3(T_i,T_s,T_r)=0\end{array}\right.---\left(6\right)$

B. calculate and receive satellite thermal insulating layer thickness and leaking heat

Note thermofin thickness is δ _s, be Q by the heat of thermofin _Is, Q then _IsAs the formula (6):

Q _is＝λ _sF _s(T _i-T _s)/δ _s (7)

λ wherein _sBe the equivalent heat transfer coefficient of thermofin, Q _IsAlso can obtain by radiation heat transfer analysis to thermofin and space outerpace, suc as formula (7):

$Q_{\mathrm{is}}=F_s{\mathrm{\σ\ϵ}}_{\mathrm{eq}2}{T}_s^4-Q_s---\left(8\right)$

ε when formula (4), formula (7) and formula (8) can obtain stable state _Eq1And δ _sRelation as the formula (9):

${\mathrm{\λ}}_s{F}_s(T_i-T_s)/{\mathrm{\δ}}_s=F_s{\mathrm{\σ\ϵ}}_{\mathrm{eq}1}(T_i^4-T_s^4)---\left(9\right)$

So ${\mathrm{\λ}}_s={\mathrm{\σ\ϵ}}_{\mathrm{eq}1}(T_s^2+T_i^2)(T_s+T_i){\mathrm{\δ}}_s.$

Can get the equivalent radiance of thermofin by formula (8):

ε _eq1＝ε/[(N+1)(2-ε)] (10)

ε is the radiance of individual layer thermoscreen, and N is the number of plies of thermoscreen.

The heat that the note radiator is radiated outside the space is Q _Ir, Ф _rBe the rate of heat dissipation of radiator, then Q _IrAnd Ф _rRespectively suc as formula shown in (12) and the formula (13).

Q _ir＝K _irF _r(T _i-T _r) (11)

C. find the solution and receive the explicit solution of each temperature set total units temperature of satellite

Can solve T according to each amount among the b by (6) formula _i, T _sAnd T _rAbout the explicit solution of radiating surface area and thermofin thickness suc as formula (12) form:

$\left\{\begin{array}{c}{T}_i=g_1(F_r,{\mathrm{\δ}}_s)\\ T_s=g_2(F_r,{\mathrm{\δ}}_s)\\ T_r=g_3(F_r,{\mathrm{\δ}}_s)\end{array}\right.--\left(12\right)$

(2) receive satellite passive heat management system optimal design mathematics model

The fundamental purpose of nano-satellite hot system design is to keep to receive each temperature set total units of satellite under suitable temperature, to guarantee to receive instrument operate as normal in safety satellite operation and the star.In optimization, choose F _rAnd δ _sAs optimization variable, establishing the optimization aim function is f (F _r, δ _s), f (F then _r, δ _s)=w ₁(T _i-T _Ib) ²+ w ₂(T _s-T _Sb) ²+ w ₃(T _r-T _Rb) ², w ₁, w ₂, w ₃Be each temperature set total units corresponding weights coefficient in objective function, it optimizes mathematical model as the formula (14):

$\left\{\begin{array}{c}\min f(F_r,{\mathrm{\&delta;}}_s)\\ \mathrm{st}.{(T_i-T_{\mathrm{ib}})}^2\&le;e,{(T_s-T_{\mathrm{sb}})}^2\&le;e,{(T_r-T_{\mathrm{rb}})}^2\&le;e\\ 0<F_r\&le;F_{r\max },0<{\mathrm{\&delta;}}_s<{\mathrm{\&delta;}}_{s\max },0<e<0.001\end{array}\right.---\left(14\right)$

Wherein, T _Ib, T _Sb, T _RbBe respectively the optimum working temperature of given instrument room, thermally insulating housing and radiating surface; F in the present embodiment _RmaxBe taken as and receive the area of a face of satellite, δ _SmaxBe taken as 2cm, can be by the designer according to actual radiating surface area and the thermofin thickness maximum permissible value determined of requiring such as the weight requirement of satellite, volume

(3) the utilization Chaos Genetic Algorithm is received the step of satellite passive heat management system parameter optimization:

1. generation initial population.Setting the population size is P, makes number of individuals P=populationsize, and formula (2) is composed P initial value, generates P chaos sequence by logistic mapping (2), chooses the generation of the 200th number and satisfy in each sequence $\{x_{10}^{\left(k\right)},x_{20}^{\left(k\right)}\}\&Element;\left(\mathrm{0,1}\right)$ P group variable { x ₁₀ ^(k), x ₂₀ ^(k), k=1 ..., P is mapped to it then and receives the feasible solution space of satellite thermal insulating layer thickness and radiating surface area, obtains the variable gene as the formula (15):

x _i＝x _i0(x _imax-x _imin)+x _imin，(i＝1，2) (15)

With x ₁, x ₂Gene connect together and form individual phenotype $X_i^{\left(k\right)}=(x_1^{\left(k\right)},x_2^{\left(k\right)}),$ (k=1,2, L P) is initial population.

2. calculate each individual fitness.For minimization problem, for guaranteeing each individual fitness value all for just, individual fitness calculates as the formula (15):

$F\left(X\right)=\left\{\begin{array}{ccc}{C}_{\max }-f\left(X\right),& \mathrm{if}& f\left(X\right)<{\mathrm{<figure-callout\; id="0"\; label="C\; max"\; filenames="A20091008162200201.png,A20091008162200202.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\max }\\ 0,& \mathrm{if}& f\left(X\right)>C_{\max }\end{array}\right.---\left(15\right)$

Wherein, f (X) is the objective function of optimization problem, C _MaxFor comparing relatively large number with f (X), f (X) is as follows:

f(X)＝f(F _r，δ _s)＝w ₁(T _i-T _ib) ²+w ₂(T _s-T _sb) ²+w ₃(T _r-T _rb) ² (16)

3. selection computing.Simulate the operation of gambling dish with the random number of logistic sequence generation 0 ~ 1 and determine individual selected number of times, the realization survival of the fittest.The fitness value of remembering individual i is Fit _i, its selected probability is:

$p_{\mathrm{is}}={\mathrm{Fit}}_i/\underset{j=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{Fit}}_j---\left(17\right)$

At last, operate to determine each individual selected number of times with the simulation of the random number between 0-1 gambling dish.Because the roulette Select Error is bigger, so adopt optimum conversation strategy to guarantee the algorithm global convergence.Its way is: begin to find out individuality and minimum individuality and the best up to now individuality of fitness that fitness is the highest the current population from the first generation, replace the poorest individuality with best up to now individuality, thereby guarantee that best individuality can not destroy because of relatively poor, mutation operation.

4. crossing operation.Crossing operation is to produce new individual main method in the genetic algorithm, and the embodiment of the invention adopts even arithmetic to intersect, and is new individual by the linear combination generation of two individualities.At first, the P in the colony individual mode with at random partnered in twos, form

Individual combination; Then, the random number by between the logistic sequence generation 0～1 determines by crossover probability whether a pair of individuality intersects.If intersect, then the crossing formula according to formula (18) generates new individual:

$\left\{\begin{array}{c}{x}_1^{(k+1)}=\mathrm{\&alpha;}{x}_2^{\left(k\right)}+(1-\mathrm{\&alpha;})x_1^{\left(k\right)}\\ x_2^{(k+1)}=\mathrm{\&alpha;}{x}_1^{\left(k\right)}+(1-\mathrm{\&alpha;})x_2^{\left(k\right)}\end{array}\right.---\left(18\right)$

In the formula, α is an interaction coefficent.At last, newly-generated individuality is assessed, abandoned the new individuality that does not satisfy constraint condition, this is carried out interlace operation again to individuality, until generating qualified new individuality.

5. variation computing.Mutation operation changes some genic value on the individual chromosome coded strings with less probability, can improve the local search ability of genetic algorithm by mutation operation, keeps the diversity of population.Adopting even mutation operation to receiving in the design of satellite thermal insulating layer and radiating surface combined optimization, each locus is a change point in the specified individual coded strings successively.To each change point, by random number and variation Probability p _mDetermine whether the gene on this locus makes a variation; If variation then generates new genic value by (19):

x′ _i＝x _imin+r·(x _imax-x _imin) (19)

In the formula, r ∈ (0,1) is the random number that is generated by the logistic sequence, to the individuality computing that makes a variation.Also to assess at last, abandon the new individuality that does not satisfy constraint condition, this is carried out mutation operation again to individuality, until generating qualified new individuality new individuality.

6. new individuality is assessed.And judge whether to reach maximum evolutionary generation G; If evolutionary generation generation＜G repeats the continuation execution of 2,3,4,5 steps and evolves; If generation=G, then satisfy the evolution termination condition, finish to evolve, satellite thermal insulating layer thickness and the area-optimized result of radiating surface are received in output.

Claims (10)

1, satellite thermal insulating layer and radiating surface united optimization design parameter are determined method, it is characterized in that comprising:

Described satellite is divided into a plurality of temperature set total units,

Determine to make a combined optimization design object function (f (F of described thermofin and radiating surface _r, δ _s)) the value minimum one group of design parameter (F _r, δ _s), described optimization aim function (f (F _r, δ _s)) with the deviation positive correlation of the predetermined optimum working temperature of relative this temperature set total units of temperature of each temperature set total units in described a plurality of temperature set total units, comprising:

At described optimization aim function (f (F _r, δ _s)) whole feasible solution space search for optimizing, thereby determine preferably to satisfy the optimal design parameter of the comprehensive evaluation index of described thermofin and radiating surface.

2, united optimization design parameter according to claim 1 is determined method, it is characterized in that described at described optimization aim function (f (F _r, δ _s)) the whole feasible solution space step of searching for optimizing comprise:

Obtain making the pareto of comprehensive evaluation index optimum of the parameter of described thermofin and radiating surface to separate,

Wherein, described optimal design parameter comprises the area (F of described radiating surface _r) and the thickness (δ of described thermofin _s).

3, united optimization design parameter according to claim 2 is determined method, it is characterized in that further comprising:

A) described a plurality of temperature set total units comprises internal heat environment, shell and the radiating surface of satellite, and their temperature separately can be with its medial temperature (T separately _i, T _s, T _r) characterize.

B) definite space heat flux (Q that arrives described satellite shell and described satellite radiating surface _s, Q _r), described satellite shell and described satellite radiating surface arrange in the heat radiation mode and loose to the heat in the space outerpace external world, the heating power Q of inside satellite instrument and equipment, and satellite is at the coldest thermal condition of rail work.

C), determine the thermal balance equation of described goal systems according to the energy budget equilibrium relation between described three temperature set total units.

4, united optimization design parameter according to claim 3 is determined method, it is characterized in that the step that the pareto of the comprehensive evaluation index optimum of the described parameter that obtains making described thermofin and radiating surface separates further comprises:

H) generate chaos sequence according to chaotic maps;

I) generate initial population;

J) determine ideal adaptation degree evaluation method;

K) carry out selection operation;

L) carry out interlace operation;

M) carry out mutation operation;

N) repeat above-mentioned steps H)-M) until satisfying the loop ends condition.

5, united optimization design parameter according to claim 4 is determined method, it is characterized in that

The described step H that generates chaos sequence according to chaotic maps) further comprise:

Determine that population quantity is P, by nonlinear iteration logistic mapping x _K+1=μ x _k(1.0-x _k) generating P group chaos sequence, μ is a controlled variable in the formula, μ=4,0.0＜x _k＜1.0, $x_k\&NotElement;\left\{\mathrm{0.25,0.5,0.75}\right\}$ ，

The step I of described generation initial population) further comprise:

From the P group chaos sequence that generates, get P group Chaos Variable and be mapped to and receive the value space of satellite thermal insulating layer thickness and radiating surface area, generate individual chromosomal, obtain the phenotype of individuality;

The step J of described definite ideal adaptation degree evaluation method) further comprise:

Calculate each individual pairing target function value M (X), determine its fitness function value F (X) by transformation rule;

Carry out the step K of selection operation) further comprise:

Simulate the operation of gambling dish with the random number of logistic sequence generation 0 ~ 1, according to selecting Probability p _s, according to the principle of " survival of the fittest " from t for selecting the higher individuality of fitness the P of colony (t) as the parent individuality, carry out the genetic manipulation of P (t+1) for colony; Carry out the step L of interlace operation) further comprise: at first to the pairing in twos at random of parent individuality, according to crossover probability p _c, judge whether individuality intersects, generate the point of crossing if intersect then to shine upon with the random number of logistic sequence generation 0 ~ 1, adopt even arithmetic to intersect and generate individuality newly;

Carry out the step M of mutation operation) further comprise:

According to the variation Probability p _m, judge whether individuality makes a variation, if then generating 0～1 random number mapping by the logistic sequence, variation generates change point, adopt even variation mode to change genic value on individual certain some locus, generate new individuality.

6, determine method according to any one described united optimization design parameter among the claim 3-5, it is characterized in that: described combined optimization design object function (f (F _r, δ _s)) have a following form:

f(F _r，δ _s)＝w ₁(T _i-T _ib) ²+w ₂(T _s-T _sb) ²+w ₃(T _r-T _rb) ²

In the formula, w ₁, w ₂, w ₃Be the respective weights coefficient of each described temperature set total units in described objective function, T _Ib, T _Sb, T _RbBe respectively the optimum working temperature of internal heat environment, shell and the radiating surface of described satellite.

7, united optimization design parameter according to claim 2 is determined method, it is characterized in that:

Area (the F of described radiating surface _r) and the thickness (δ of described thermofin _s) comprise the thickness (δ of the thermofin that the multilayer insulation assembly is formed respectively _s) and radiating surface area (F _r).

8, united optimization design parameter according to claim 3 is determined method, it is characterized in that: described optimization aim function (f (F _r, δ _s)) mathematical optimization models of searching for optimizing in whole feasible solution space can be expressed as:

$\left\{\begin{array}{c}\min f(F_r,{\mathrm{\&delta;}}_s)\\ \mathrm{st}.{(T_i-T_{\mathrm{ib}})}^2\&le;e,{(T_s-T_{\mathrm{sb}})}^2\&le;e,{(T_r-T_{\mathrm{rb}})}^2\&le;e\\ 0<F_r\&le;F_{r\max },0<{\mathrm{\&delta;}}_s<{\mathrm{\&delta;}}_{s\max },0<e<0.001\end{array}\right..$

9, united optimization design parameter according to claim 5 is determined method, it is characterized in that:

Described population quantity P is 60;

Described P group Chaos Variable is got the 200th Chaos Variable respectively and is obtained from the P group chaos sequence that generates;

0 ~ 1 random number of described simulation gambling dish operation produces with the logistic sequence;

Described point of crossing is produced 0 ~ 1 random number mapping generation by the logistic sequence;

Described change point is generated by the random number mapping that is produced 0 ~ 1 by the logistic sequence;

Described crossover probability is between 0.6-0.75;

Described variation probability is between 0.2-0.32.

10, united optimization design parameter according to claim 5 is determined method, and wherein said goal systems is for receiving satellite.

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