CN111523175A - Pop-up star sensor light shield and design method thereof - Google Patents
Pop-up star sensor light shield and design method thereof Download PDFInfo
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Abstract
The invention discloses a pop-up star sensor light shield and a design method thereof, wherein the pop-up star sensor light shield comprises the following components: a plurality of sections of mutually nested light shields, cylindrical helical compression springs and fusing devices; the light shield comprises an expansion state and a contraction state, each section of light shield comprises a main body part and a corresponding connecting part, and the main body part and the corresponding connecting part are in threaded connection; the cylindrical helical compression spring comprises a plurality of sections, is arranged on each section of the light shield and is used for driving each section of the light shield to expand; fusing device includes that controller, heater, special fixed line and fixed mounting seat constitute, and special fixed line twines on the heater in the fixed mounting seat, makes special control line fracture through the heating of controller control heater heating to make the lens hood pop out and expand. The pop-up star sensor light shield can effectively reduce the volume of the star sensor in a non-working state, is beneficial to the internal layout of a spacecraft and reduces the space required by launching, and has very high practical value.
Description
Technical Field
The invention relates to the technical field of spaceflight, in particular to a pop-up star sensor light shield and a design method thereof.
Background
The star sensor is the attitude sensor with the highest precision in attitude measurement of the spacecraft, extracts a vector of a fixed star in a star sensor coordinate system by shooting a starry sky image of a specific area, and can obtain an attitude transformation matrix of the star sensor relative to the star coordinate system by converting the vector of the fixed star in the star coordinate system, so that the three-axis attitude of the spacecraft is obtained. The star sensor light shield can effectively eliminate the influence of earth atmosphere reflected light, sunlight and stray light emitted by various stars when the star sensor performs star point imaging, so that the background noise of the star sensor is reduced, and important guarantee is provided for the star sensor to extract star point coordinates and calculate the attitude.
The star sensor light shield is usually fixed on a shell of the star sensor, and most of the existing star sensor light shields are integrally machined and designed, are large in size and occupy most of the space of the whole star sensor. Generally, when a star sensor is installed on a spacecraft, a light shield of the star sensor is exposed outside the spacecraft, the light shield of the star sensor can play a role in eliminating stray light after the star sensor works, and the light shield of the star sensor not only can increase the overall volume of the spacecraft, but also can influence the emission layout so as to increase the required emission space.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, an object of the present invention is to provide a pop-up type star sensor shade which is in a retracted state before the star sensor is not operated and pops up and expands after the star sensor enters an operating state, thereby solving the problem of space occupation of the star sensor shade.
Another objective of the present invention is to provide a design method of a pop-up star sensor light shield.
In order to achieve the above object, an embodiment of the invention provides a pop-up star sensor light shield, including:
a plurality of sections of mutually nested light shields, cylindrical helical compression springs and fusing devices;
the light shield comprises an expansion state and a contraction state, each section of light shield comprises a main body part and a corresponding connecting part, and the main body part is in threaded connection with the corresponding connecting part;
the cylindrical helical compression spring comprises a plurality of sections, is arranged on each section of the light shield and is used for driving each section of the light shield to expand;
the fusing device is composed of a controller, a heater, a special fixing line and a fixed mounting seat, wherein the special fixing line is wound on the heater in the fixed mounting seat, and the heater is controlled by the controller to heat so that the special control line is broken, and the light shield is popped out and unfolded.
According to the pop-up type star sensor hood disclosed by the embodiment of the invention, through designing the pop-up type hood, the mechanical property and the optical property are not obviously weakened, when the star sensor does not work, all stages of hoods are in a contracted state, when the star sensor works, the fusing device is started to drive all stages of hoods to be unfolded by the spring, the volume of the hoods when the star sensor does not work is greatly reduced, the internal subsystem layout of the spacecraft is increased, the launching space required by the spacecraft is reduced, the miniaturization of the spacecraft and the launching number of the spacecraft at one time can be promoted to a certain extent, and the pop-up type star sensor hood has very high practical value.
In addition, the pop-up star sensor light shield according to the above embodiment of the present invention may have the following additional features:
in the embodiment of the invention, the light shield is three sections, the sections are mutually nested, each section comprises two parts, and the main part of the light shield is A1、A2、A3Respectively of length H1、H2、H3(ii) a The corresponding connecting part is B1、B2、B3Each length of l1、l2、l3(ii) a Main part A of light shieldiWith corresponding connecting portion BiThe two are connected by screw thread; in the contraction state, the gap distance between the adjacent light shields is h1、h2、h3Wherein h isiNot less than 4mm, distance x from each segment of lens hood to light aperture of lensiAnd the light shield satisfies the following conditions:
wherein HiA length corresponding to the main body part of the light shield hiThe gap distance between adjacent light shields is represented by i, i is 1,2, and 3.
In an embodiment of the present invention, the light shield main body portion AiThe profile of the cone is designed to be a taper with a taper angle of α, wherein, α∈ [0.5 degrees ], 5 degrees]Corresponding connecting part BiCan be divided into two parts, a first part bxiIs threaded with the main body part A of the shadeiIs of length lxiWherein l isxiNot less than 3mm, the inner part is designed to be taper and the main body part AiThe conicity of the conical sections is equal; second part byiIs the first part bxiPerpendicular right angle part of length lyiCorresponding connecting part BiWith the length of the two parts satisfying li＝lxi+lyiWherein l isiIs a corresponding connecting part BiLength of the corresponding connecting portion B in the fully unfolded state of the shadeiIs spaced from the bottom end surface by a distance larger than
Wherein HiI is the length corresponding to the main part of the light shield, i is the number of the light shield, and i is 1,2 and 3; corresponding connection part B in the completely contracted state of the light shieldiThe bottom surface is tightly attached to the end surface of the bottom of the light shield.
In an embodiment of the present invention, the constraint relationship between the taper portion of the main body portion of the light shield and the light shield is
Wherein α is the angle of taper of the main body portion of the mask, DiIs a main body part A of the light shieldiLarge end diameter of diIs a main body part A of the light shieldiSmall end diameter of, light shield main body portion AiWith corresponding connecting portion Bi+1The coefficient of friction between mu satisfies mu < tan α, wherein A0Showing the lens holder body portion.
In the embodiment of the invention, the connecting part B corresponding to the light shieldiAnd a light shield main body part Ai-1In the radial direction ofThe matching clearance is delta m, and the connecting part B corresponding to the light shieldiContact length with the lens hood is piAnd satisfy pi>Di-1sin α, wherein Di-1Is a main body part A of the light shieldi-1The big end diameter of α for the taper angle of lens hood main part, at the complete unwrapping state of lens hood, when the lens hood big end received radial effort, the angle theta that takes place relative slope between the adjacent lens hood was:
wherein the content of the first and second substances,
the inclination angle theta satisfies the condition that theta is less than thetam，θmAnd determining the maximum value of the fit clearance delta m according to an inclination angle formula for the maximum deformation angle of the light shield.
In the embodiment of the invention, the unfolding of the light shield sections is driven by the cylindrical helical compression springs with the outer diameter DsiSatisfies Dsi＜di，diIs a main body part A of the light shieldiThe small end diameter of (a); when the light shield is in a contraction state, each section of cylindrical helical compression spring is in a compression state, and the compression height H of each section of cylindrical helical compression springbiSatisfy Hbi＜hi，hiIs the gap distance between adjacent light shields; when the light shield is in an unfolded state, each section of cylindrical helical compression spring is still in a compressed state, and the free height of each section of cylindrical helical compression spring meets the requirement of Hoi＜Hi，HiIs a main body part of a light shieldThe corresponding length is divided, when the light shield is in a fully unfolded state, each section of the cylindrical helical compression spring meets the following relation:
kΔxi>κμNi
wherein k is the hooke's coefficient of the cylindrical helical compression spring, κ is a scaling factor, Δ xiIs the deformation quantity of the ith section of cylindrical helical compression spring, NiDenotes the corresponding connecting part BiFor the main body part Ai-1Positive pressure of (2).
In the embodiment of the invention, the special fixing lines are used for placing the light shields in a contraction state, the controller receives a control command, the heater is controlled by the controller to heat the special fixing lines to break, the light shields are released from the contraction state, and the light shields in all sections are ejected and unfolded under the driving force of the cylindrical spiral compression spring.
In an embodiment of the invention, the light shield main body part and the connecting part thereof are made of aluminum alloy, the inner wall of the light shield is sprayed with a material with high absorptivity and low scattering rate, and the outer surface of the light shield main body part and the inner surface of the connecting part are sprayed with polytetrafluoroethylene materials.
In order to achieve the above object, another embodiment of the present invention provides a method for designing a pop-up star sensor light shield, comprising:
determining the diameter, the length and the shield wall taper of each section of the light shield according to the number of the segments of the light shield, the geometric design principle of a secondary scattering light shield structure, the geometric structure requirement of the light shield and the frictional resistance when the light shield is ejected;
determining the friction coefficient of the light shield according to the taper of the wall of the light shield, and determining the contact length and the matching relation between the light shield and the corresponding connecting part according to the inclination angle of the light shield in the fully unfolded state;
the fusing device is used for controlling the contraction and expansion of each section of light shield, the cylindrical helical compression spring is used for driving each section of light shield to expand, the diameter, the compression height and the free height of the cylindrical helical compression spring are determined according to the diameter and the completely contracted and expanded length of each section of light shield, and the material and the model of the cylindrical helical compression spring are determined according to the frictional resistance when each section of light shield is popped up.
According to the design method of the pop-up type star sensor light shield provided by the embodiment of the invention, through designing the light shield capable of popping up, the mechanical property and the optical property are not obviously weakened, when the star sensor does not work, each stage of light shield is in a contracted state, when the star sensor works, the fusing device is started to drive each stage of light shield to expand by the spring, the size of the light shield when the star sensor does not work is greatly reduced, the internal subsystem layout of the spacecraft is increased, the launching space required by the spacecraft is reduced, the miniaturization of the spacecraft and the launching number of the spacecraft in a single time can be promoted to a certain extent, and the design method has a very high practical value.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic view of a fully extended pop-up star sensor light shield in accordance with one embodiment of the present invention;
FIG. 2 is a schematic view of a retracted state of the pop-up star sensor light shield according to one embodiment of the present invention;
FIG. 3 is a schematic view of a pop-up star sensor light shield design according to one embodiment of the present invention;
fig. 4 is a schematic diagram of the self-locking force during pop-up of the pop-up shade according to an embodiment of the present invention;
FIG. 5 is an oblique view of a light shield according to one embodiment of the present invention in a fully extended state;
FIG. 6 is an integrated light shield having the same aperture position as the pop-up star sensor light shield of the embodiment of the present invention;
FIG. 7 is a graph comparing the PST of the optical performance of the two light shields of FIGS. 1 and 6;
fig. 8 is a flow chart of a method for designing a pop-up star sensor light shield in accordance with one embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
A pop-up star sensor shade and a method of designing the same according to an embodiment of the present invention will be described below with reference to the accompanying drawings.
First, a pop-up star sensor shade proposed according to an embodiment of the present invention will be described with reference to the accompanying drawings.
Fig. 1 is a schematic view of a fully deployed pop-up star sensor light shield in accordance with one embodiment of the present invention.
FIG. 2 is a schematic view of a retracted state of the pop-up star sensor light shield according to one embodiment of the present invention.
As shown in fig. 1 and 2, the pop-up star sensor shade includes: a plurality of segments of light shields nested within one another, a cylindrical helical compression spring, and a fusing device. The fusing device of the pop-up star sensor light shield is positioned on the star sensor electronic cabin.
In the embodiment of the invention, the light shield comprises an expansion state and a contraction state, each light shield comprises a main body part and a corresponding connecting part, and the main body part and the corresponding connecting part are connected by screw threads. The cylindrical helical compression spring comprises a plurality of sections, is arranged on each section of the light shield and is used for driving each section of the light shield to expand. Fusing device includes that controller, heater, special fixed line and fixed mounting seat constitute, and special fixed line twines on the heater in the fixed mounting seat, makes special control line fracture through the heating of controller control heater heating to make the lens hood pop out and expand.
Further, as a specific embodiment, the pop-up star sensor shade is divided into three sections, each section is nested with each other, and each section comprises twoA main part of the light shield1、A2、A3Respectively of length H1、H2、H3(ii) a The corresponding connecting part is B1、B2、B3Each length of l1、l2、l3；AiAnd BiThe two are connected by screw thread; in the contraction state, the gap distance between the adjacent light shields is h1、h2、h3And h isiNot less than 4 mm; distance x from each segment of lens hood to light transmission caliber of lensiAnd the light shield satisfies the following conditions:
wherein HiA length corresponding to the main body part of the light shield hiThe gap distance between adjacent light shields is represented by i, i is 1,2, and 3.
Specifically, referring to fig. 3, the distance x from each segment of the light shield to the clear aperture of the lensiThe method is determined according to the geometric design principle of the secondary scattering light shield structure, and specifically comprises the following steps:
1) according to the ground gas light inhibition angle required by the star sensor
Determining the theoretical length L of the lens hood and the light-entering end clear aperture D of the lens hood according to the lens clear aperture D and the half field angle theta of the lens hood:
D＝d+2×L×tanθ
2) as shown in fig. 3, a rectangular coordinate system is established with the center o of the lens clear aperture d of the mask as the center and the axial direction of the mask as the x axis. The coordinates of the point A of the clear aperture of the star sensor lens can be obtained
Coordinates of A' point
B point coordinate of light inlet end of lens hood
Coordinates of point B
Edge straight line l of first segment of lens hood1Has the linear equation of
Second segment of lens hood edge straight line l2Has the linear equation of
Third segment of lens hood edge straight line l3Has the linear equation of
3) The point B' of the light inlet end of the star sensor light shield is taken as a starting point, and the sunlight suppression angle omega is based on the star sensor so as to ensure that the point B is on a straight line l along the edge of the first segment light shield3Hereinafter, the diameter D of the first segment of the light shield1The following relationship should be satisfied:
D1≥2×L×tanω-D
otherwise, returning to the step 1), re-determining the theoretical length L of the light shield and the light-entering end clear aperture D of the light shield, or re-determining the diameter D of the first section of the light shield1。
4) Determining the position (x) of the first-order diaphragm C point of the lens hood based on the sunlight suppression angle omega and the half field angle theta of the lens hoodc,yc). The straight line B' D and the view field contour line AB are intersected at the point C, and according to the coordinates of the point A and the point B, the equation of the straight line AB can be obtained as follows:
and then, according to the coordinates of the point B ' and the point D ', the equation of a straight line B ' D can be obtained as follows:
the position coordinate (x) of the point C can be obtained by combining the equation of the straight line AB and the equation of the straight line B' Dc,yc)：
Passing through C point to make vertical line and then passing through straight line l at edge of second segment of lens hood2And E, CE is the primary diaphragm of the lens hood.
5) Diameter d based on lens clear aperture d and second segment lens hood2And the light-entering end clear aperture D of the whole light shield, and determining the position (x) of the second-stage diaphragm G point of the light shieldG,yG). In order to obtain the position of the G point of the second stage diaphragm of the light shield, the position coordinates of the F point must be obtained first. Is connected with A' C and is used as an extension line thereof to be crossed with a straight line l at the edge of the second segment of the lens hood3At point F, based on the coordinates of point a and point C, the equation of the straight line a' C can be derived as:
according to the edge line l of the second segment of the lens hood2The coordinates of point F can be obtained as:
connecting the intersection field contour line AB of B 'F with the point G, and obtaining the linear equation of B' F according to the coordinates of the point B and the point F as follows:
combining the equation of B' F with the equation of the field contour AB, the coordinate of the point G can be obtained as follows:
passing point G is perpendicular line and is crossed with a third segment of lens hood edge straight line l3And H, GH is the secondary diaphragm of the lens hood.
6) The invention can design two diaphragms in the whole lens hood. The extension line of A' G is connected with point K, and the point K is not located on the edge of the third segment of the lens hood3Upper, diameter d of the third segment of the light shield3It should satisfy:
the light inlet end of the whole light shield is a three-stage diaphragm of the light shield, and the design of the pop-up light shield is completed. Otherwise, changing the design parameters to make the point K fall on the diaphragm of the light inlet end of the integral lens hood. Therefore, the distance x from the first segment of the light shield to the clear aperture of the lens1＝xc(ii) a Distance x from second segment of lens hood to light aperture of lens2＝xG(ii) a Distance x from second segment of lens hood to light aperture of lens1＝D。
The distance x from each segment of lens hood to the clear aperture of the lens determined by the geometric design principle of the secondary scattering lens hood structureiAnd the light shield should satisfy:
wherein i is 1,2, 3.
As a specific example, h1＝h2＝h3＝4mm，H1＝x1+2h1，H2＝x1-H1+h2+2h1，H3＝x3-H2-H1+h3+h2+2h1。
Further, in the embodiment of the present invention, the light shield main body portion aiThe profile of the cone is designed to be a taper with a taper angle of α, wherein, α∈ [0.5 degrees ], 5 degrees]Because of the body part AiThe partial taper angle α is small, and the calculated diaphragm position does not change much in consideration of α, so that the design using the geometric design principle of the secondary scattering light shield structure can meet the optical requirements of the light shield under the condition of α being equal to 0.
Corresponding connecting part BiCan be divided into two parts, a first part bxiIs threaded with the main body part A of the shadeiIs of length lxiWherein l isxiNot less than 3mm, the inner part is designed to be taper and the main body part AiThe conicity of the conical sections is equal; second part byiIs the first part bxiPerpendicular right angle part of length lyiCorresponding connecting part BiWith the length of the two parts satisfying li＝lxi+lyiWherein l isiIs a corresponding connecting part BiLength of (d).
As a specific example, when the shade has three segments, the corresponding connecting part B1And B2Only the first part bxi，B3Comprising two parts.
In the fully unfolded state of the shade, the corresponding connecting portion BiIs spaced from the bottom end surface by a distance larger than
Wherein HiI is the length corresponding to the main part of the light shield, i is the number of the light shield, and i is 1,2 and 3; corresponding connection part B in the completely contracted state of the light shieldiThe bottom surface is tightly attached to the end surface of the bottom of the light shield.
Specifically, B1To the bottom endA face distance of H1-l1+L0，B2A distance H from the bottom end face1+H2-l2+L0，B3A distance H from the bottom end face1+H2+H3-l3+L0，L0The length of the lens fixing seat.
Further, in the taper angle of the pop-up star sensor light shield, the constraint relation between the taper part and the light shield is
Wherein D isiIs a main body part A of the light shieldiLarge end diameter of diIs a main body part A of the light shieldiThe small end diameter of (a). Light shield AiAnd the connecting part Bi+1When the friction coefficient mu is less than tan α, the self-locking phenomenon can not occur in the process of the light shield ejection.
Specifically, the stress of the self-locking state of the light shield is as shown in fig. 4, taking the first section of light shield and the second section of light shield as an example, assuming that the spring acting force T is along the central line direction of the second section of light shield, the following stress equation is satisfied, and the light shield is self-locked:
f2cos(α+β)+f1cos(β-α)＝Tcosβ
f2sin(α+β)+f1sin(β-α)＝Tsinβ
wherein, the friction force f received by the second segment of the light shield1And f2Comprises the following steps:
f1＝μF1
f2＝μF2
wherein the force T of the spring can be resolved into F according to the direction1And F2According to the geometrical relationship:
F1＝F2＝F
substituting the above formula into the self-locking equation, the critical conditions for self-locking can be:
tanα＝μ
the conditions for preventing the self-locking of the light shield are as follows:
tanα>μ
further, in the designed pop-up star sensor light shield, the corresponding connecting part B of the light shieldiAnd a light shield main body part Ai-1The radial fit clearance is delta m, and the connecting part B corresponding to the light shieldiContact length with the lens hood is piAnd need to satisfy pi>Di-1sin α, when the light shields are in the fully unfolded state, as shown in fig. 5, the angle θ between adjacent light shields when the large ends of the light shields are subjected to radial force is derived as follows:
in a triangular ACD, the signal is represented by the cosine theorem:
S2+(R-Δ)2-2S(R-Δ)cos(90+β-α)＝R2
wherein:
obtaining by solving:
to swap out β, in a triangular ACF, we have the following sine theorem:
further obtaining sin (alpha-beta) and cos (alpha-beta):
the angle of inclination θ is:
in a triangular ACF, according to the cosine theorem:
R2＝p2+(D+Δm)2-2p(D+Δm)sinα
the resulting relative tilt angle θ is:
wherein:
the inclination angle should satisfy theta < thetam，θmThe maximum value of the fit clearance Δ m can be determined according to the inclination angle formula for the maximum deformation angle of the light shield.
Further, in the designed pop-up type star sensor light shield, the unfolding of each section of light shield is driven by each section of cylindrical helical compression spring, and the outer diameter D of each section of cylindrical helical compression springsiShould satisfy Dsi＜di(ii) a When the light shield is in a contraction state, each section of cylindrical helical compression spring is in a compression state, and the compression height H of each section of cylindrical helical compression springbiShould satisfy Hbi＜hi(ii) a When the light shield is in an unfolded state, each section of cylindrical spiral compression spring is still in a compressed state, and each section of cylindrical spiral isThe free height of the spinning compression spring is required to satisfy Hoi＜Hi. In order to ensure that the light shields of the respective sections can be popped out and unfolded, when the light shields are in a fully unfolded state, the springs need to satisfy the following relationship:
kΔxi＞κμNi
wherein k is the hooke's coefficient of the cylindrical helical compression spring, κ is a scaling factor, Δ xiIs the deformation quantity of the ith section of cylindrical helical compression spring, NiIs represented by BiTo Ai-1Positive pressure of (2).
Further, in the designed pop-up star sensor light shield, the fusing device consists of a controller, a heater, a special fixing wire and a fixed mounting seat, wherein the special fixing wire is wound on the heater in the fixed mounting seat. The pop-up star sensor light shield is placed in a shrinkage state through the special fixing line, other equipment or the star sensor sends a control command to a controller of the light shield, and then the controller controls the fusing device to heat the special fixing line through the heater to enable the special fixing line to be broken, so that the star sensor light shield is released from the shrinkage state, and all the light shields pop up and expand under the support of the acting force of the cylindrical spiral compression spring.
In one embodiment of the present invention, the length of the third section of the hood from the top end to the bottom end of the hood is 74.46mm when the hood is extended and the length of the third section of the hood from the top end to the bottom end of the hood is approximately 30.5mm when the hood is retracted. The length of the star sensor light shield when the star sensor does not work is effectively shortened, and the space layout and the space required by spacecraft launching are facilitated.
In order to verify the influence of the improved light shield with certain taper on the positions of the diaphragms at all levels, an integrated light shield with the same diaphragm position as the pop-up star sensor light shield is designed as shown in fig. 6. As a result of using the point light source transmission (PST) as an evaluation index of the optical performance of the light shield, the stray light suppression capability of the two light shields was almost the same for different solar incident angles as shown in fig. 7. Therefore, the pop-up light shield provided by the invention has good optical performance.
In the embodiment of the invention, each section of the light shield is made of aluminum alloy, and has the characteristics of low cost and light weight, and the inner wall of the light shield is sprayed with the material with high absorptivity and low scattering rate, so that the extinction performance of the light shield is improved. The cylindrical helical compression spring is made of standard spring products. The outer surface of the main body part of the light shield and the inner surface of the connecting part are sprayed with polytetrafluoroethylene materials, so that the friction force between the light shields is further reduced when the light shield is ejected.
Next, a method of designing a pop-up star sensor shade according to an embodiment of the present invention will be described with reference to the drawings.
Fig. 8 is a flow chart of a method for designing a pop-up star sensor light shield in accordance with one embodiment of the present invention.
As shown in fig. 8, the design method of the pop-up star sensor light shield includes:
s1, determining the diameter, length and wall taper of each segment of the light shield according to the number of segments of the light shield, the geometric design principle of a secondary scattering light shield structure, the geometric structure requirement of the light shield and the frictional resistance when the light shield is ejected;
s2, determining the friction coefficient of the light shield according to the taper of the light shield wall, and determining the contact length and the matching relation between the light shield and the corresponding connecting part according to the inclination angle of the light shield in the fully unfolded state;
and S3, controlling the contraction and expansion of each segment of light shield through a fusing device, driving the expansion of each segment of light shield through a cylindrical helical compression spring, determining the diameter, the compression height and the free height of the cylindrical helical compression spring according to the diameter and the completely contracted and expanded length of each segment of light shield, and determining the material and the model of the cylindrical helical compression spring according to the frictional resistance when each segment of light shield is popped up.
It should be noted that the above explanation of the embodiment of the pop-up star sensor light shield also applies to the design method of the embodiment, and is not repeated herein.
According to the design method of the pop-up type star sensor light shield provided by the embodiment of the invention, through designing the light shield capable of popping up, the mechanical property and the optical property are not obviously weakened, when the star sensor does not work, each stage of light shield is in a contraction state, when the star sensor works, the fusing device is started to enable the spring to drive each stage of light shield to expand, the volume of the light shield when the star sensor does not work is greatly reduced, the internal subsystem layout of the spacecraft is increased, the launching space required by the spacecraft is reduced, the miniaturization of the spacecraft and the launching number of the spacecraft in a single time can be promoted to a certain extent, and the design method has very high practical value.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (9)
1. A pop-up star sensor light shield, comprising:
a plurality of sections of mutually nested light shields, cylindrical helical compression springs and fusing devices;
the light shield comprises an expansion state and a contraction state, each section of light shield comprises a main body part and a corresponding connecting part, and the main body part is in threaded connection with the corresponding connecting part;
the cylindrical helical compression spring comprises a plurality of sections, is arranged on each section of the light shield and is used for driving each section of the light shield to expand;
the fusing device is composed of a controller, a heater, a special fixing line and a fixed mounting seat, wherein the special fixing line is wound on the heater in the fixed mounting seat, and the heater is controlled by the controller to heat so that the special control line is broken, and the light shield is popped out and unfolded.
2. The pop-up star sensor light shield of claim 1,
the light shield is three sections, each section is mutually nested, each section comprises two parts, and the main part of the light shield is A1、A2、A3Respectively of length H1、H2、H3(ii) a The corresponding connecting part is B1、B2、B3Each length of l1、l2、l3(ii) a Main part A of light shieldiWith corresponding connecting portion BiThe two are connected by screw thread; in the contraction state, the gap distance between the adjacent light shields is h1、h2、h3Wherein h isiNot less than 4mm, distance x from each segment of lens hood to light aperture of lensiAnd the light shield satisfies the following conditions:
wherein HiA length corresponding to the main body part of the light shield hiBetween adjacent light shieldsThe gap distance i is the shade number, i is 1,2, 3.
3. The pop-up star sensor light shield of claim 1,
main part A of light shieldiThe profile of the cone is designed to be a taper with a taper angle of α, wherein, α∈ [0.5 degrees ], 5 degrees]Corresponding connecting part BiCan be divided into two parts, a first part bxiIs threaded with the main body part A of the shadeiIs of length lxiWherein l isxiNot less than 3mm, the inner part is designed to be taper and the main body part AiThe conicity of the conical sections is equal; second part byiIs the first part bxiPerpendicular right angle part of length lyiCorresponding connecting part BiWith the length of the two parts satisfying li＝lxi+lyiWherein l isiIs a corresponding connecting part BiLength of the corresponding connecting portion B in the fully unfolded state of the shadeiIs spaced from the bottom end surface by a distance larger than
Wherein HiI is the length corresponding to the main part of the light shield, i is the number of the light shield, and i is 1,2 and 3; corresponding connection part B in the completely contracted state of the light shieldiThe bottom surface is tightly attached to the end surface of the bottom of the light shield.
4. The pop-up star sensor light shield of claim 1,
the constraint relation between the taper part of the main body part of the light shield and the light shield is
Wherein α is the angle of taper of the main body portion of the mask, DiIs a main body part A of the light shieldiLarge end diameter of diIs a main body part A of the light shieldiSmall end diameter of, light shield main body portion AiWith corresponding connecting portionsBi+1The coefficient of friction between mu satisfies mu < tan α, wherein A0Showing the lens holder body portion.
5. The pop-up star sensor light shield of claim 1,
connecting part B corresponding to the light shieldiAnd a light shield main body part Ai-1The radial fit clearance is delta m, and the connecting part B corresponding to the light shieldiContact length with the lens hood is piAnd satisfy pi>Di-1sin α, wherein Di-1Is a main body part A of the light shieldi-1The big end diameter of α for the taper angle of lens hood main part, at the complete unwrapping state of lens hood, when the lens hood big end received radial effort, the angle theta that takes place relative slope between the adjacent lens hood was:
wherein the content of the first and second substances,
the inclination angle theta satisfies the condition that theta is less than thetam，θmAnd determining the maximum value of the fit clearance delta m according to an inclination angle formula for the maximum deformation angle of the light shield.
6. The pop-up star sensor light shield of claim 1,
the light shield is driven to be unfolded by each section of cylindrical helical compression spring, and the outer part of each section of cylindrical helical compression springDiameter DsiSatisfies Dsi＜di，diIs a main body part A of the light shieldiThe small end diameter of (a); when the light shield is in a contraction state, each section of cylindrical helical compression spring is in a compression state, and the compression height H of each section of cylindrical helical compression springbiSatisfy Hbi＜hi，hiIs the gap distance between adjacent light shields; when the light shield is in an unfolded state, each section of cylindrical helical compression spring is still in a compressed state, and the free height of each section of cylindrical helical compression spring meets the requirement of Hoi＜Hi，HiFor the length that the lens hood main part corresponds, when the lens hood is in the complete expansion state, each section cylindrical helical compression spring satisfies following relation:
kΔxi>κμNi
wherein k is the hooke's coefficient of the cylindrical helical compression spring, κ is a scaling factor, Δ xiIs the deformation quantity of the ith section of cylindrical helical compression spring, NiDenotes the corresponding connecting part BiFor the main body part Ai-1Positive pressure of (2).
7. The pop-up star sensor light shield of claim 1,
the special fixing lines are used for placing the light shields in a contraction state, the controller receives a control instruction, the heater is controlled by the controller to heat the special fixing lines to enable the special fixing lines to be broken, the light shields are released from the contraction state, and all the light shields are ejected out and unfolded under the driving of the acting force of the cylindrical spiral compression spring.
8. The pop-up star sensor light shield of claim 1,
the inner wall of the light shield is sprayed with a material with high absorptivity and low scattering rate, and the outer surface of the light shield main body and the inner surface of the connecting part are sprayed with polytetrafluoroethylene materials.
9. A design method of a pop-up star sensor light shield is characterized by comprising the following steps:
determining the diameter, the length and the shield wall taper of each section of the light shield according to the number of the segments of the light shield, the geometric design principle of a secondary scattering light shield structure, the geometric structure requirement of the light shield and the frictional resistance when the light shield is ejected;
determining the friction coefficient of the light shield according to the taper of the wall of the light shield, and determining the contact length and the matching relation between the light shield and the corresponding connecting part according to the inclination angle of the light shield in the fully unfolded state;
the fusing device is used for controlling the contraction and expansion of each section of light shield, the cylindrical helical compression spring is used for driving each section of light shield to expand, the diameter, the compression height and the free height of the cylindrical helical compression spring are determined according to the diameter and the completely contracted and expanded length of each section of light shield, and the material and the model of the cylindrical helical compression spring are determined according to the frictional resistance when each section of light shield is popped up.
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| CN111523175B (en) | 2022-11-08 |
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Application publication date: 20200811 Assignee: Beijing Yizhi Manufacturing Technology Co.,Ltd. Assignor: TSINGHUA University Contract record no.: X2023990000349 Denomination of invention: A pop-up star sensor hood and its design method Granted publication date: 20221108 License type: Common License Record date: 20230327 |