RU2662620C1 - Device for control of the orientation of spacecrafts at approach - Google Patents

Abstract

FIELD: optics; electronic equipment.

SUBSTANCE: invention relates to optoelectron devices used in spacecraft motion control systems, mainly to the docking target of passive spacecraft. Target with a high absorption coefficient of its surface is located outside the port of docking. Axis OA of target (looking at us) is parallel to the axis OX of spacecraft. On basis (13) in the plane of the axes OB and OC, there are light sources (LS): disk LS (1), the first (2) and the second (5) linear LSs. Additional LSs: the first (3) and the second (4) are located at the center of LS (2), and the third (6) and the fourth (7) – at the center of LS (5). Lens hood (10) of LS (1) and the hole in inner ring (11) with an absorbent coating determine angular dimension (2α ≈ 3°) of emission cone of LS (1). LS (1) with a lens hood (10) serves to control the alignment of the axes of approaching spacecrafts. Outer ring (12) with a reflective coating serves to quickly locate LS (1). Photosensor (8) with control unit (9) of the LS allows to control the mutual orientation of the spacecrafts in a wide range of background illumination of the target. All LSs are equipped with shielding elements (15–17, 19–21), and linear LSs are also provided with lens hoods (14, 18).

EFFECT: technical result consists in increasing the ergonomic and functional characteristics of the device.

1 cl, 6 dwg

Description

The invention relates to the field of optoelectronic instrumentation and is intended for use in motion control systems (SUD) of a spacecraft (KA) to ensure convergence and docking operations of spacecraft.

Analogs of the proposed device are the docking targets described in the literature: “Encyclopedia of Mechanical Engineering, Volume IV-22, Rocket and Space Technology, Book 2, Part II, Chapter 4.4. Motion control and navigation system. Moscow "Engineering" 2014 ".

The relevance of the use of targets in the ACS of the spacecraft is confirmed by each operation of the approach and docking of the spacecraft with the international space station (ISS). Almost all ports for docking are equipped with targets for both automatic and manual spacecraft control loop.

Targets are used in the spacecraft COD during rapprochement and docking to determine the relative position of the target coordinate system on the passive spacecraft and the optical sight of the astronaut VSK4 or a television camera on the active spacecraft. Targets for the manual control loop are a metal structure having a base with a black coating and a white cross, a rod mounted perpendicular to the base along the axis of the target, and a remote cross at the end of the rod. The cross is white coated. When observing along the axis of the target in the absence of a mismatch of the axes of the approaching spacecraft, the remote cross coincides with the cross at the base of the target.

However, the disadvantage of these targets is that their visibility depends on the lighting conditions. On the day side of the orbit at certain angles of the Sun, there is such a lighting of the station, to which the spacecraft is joined, that the target is in the shadow of the structural elements, while the rest of the station is brightly lit. In this case, on a television image, the target will be poorly distinguishable due to the large difference in brightness. On the night side of the orbit, the station and the target are illuminated when approaching using an LED headlight mounted on the spacecraft. Due to the parallax between the axis of view of the TV camera and the axis of radiation of the headlight, at a close distance between 5 and 3 m the target is not uniformly illuminated: the base is in the cone of the field of radiation of the headlight, and the remote cross is outside this cone. As a result, due to the large difference in brightness, the remote cross in this “dead” zone disappears on the TV image, and the operator cannot control the angle of deviation from the axis of sight.

The device presented in patent RU 2486112 "Device for controlling the orientation of passive spacecraft" can be taken as a prototype. This device includes a housing with holes and diffraction gratings located at an angle of 90 ° to each other, performing the functions of a target, as well as a illuminator. When observing the device along its axis, depending on its turn, the color of the illuminator radiation reflected from the diffraction gratings in the device changes.

The disadvantage of this device is the low efficiency of using the energy of the illuminator, since radiation in a narrow spectral range reaches the radiation receiver (a television camera or the operator’s eye when observing in an optical sight), due to the decomposition into the emission spectrum of the illuminator on diffraction gratings. Another disadvantage is that this device will not fulfill its functional purpose when observing it with a black-and-white television camera, since information about the portion of the spectrum associated with the angle of rotation of the diffraction grating, and therefore the device for black-and-white television no camera.

The objective of the present invention is to increase ergonomic characteristics and expand the functionality of the device to control the mutual orientation of the converging spacecraft.

The technical result is achieved by the fact that in the device for controlling the orientation of spacecraft during approach, containing a target with light sources, in contrast to the targets known at the beginning of the OAVS coordinate system, there is a disk light source with an axis of radiation coinciding with the OA axis, equipped with a hood, the output end of which bordered by two rings, - the inner one with a high absorption coefficient, - the outer one with a high reflection coefficient, along the axis ОВ and ОС there are linear light sources equipped with hoods, at the weekend which screening elements are located in the form of parallelograms, the planes of which are parallel to the OVS plane, the long sides of the parallelograms have an acute angle with the OV and OS axes, and additional light sources are located in the OVS plane inside the blends of linear light sources on lines perpendicular to the OV and OS axes and passing through the centers of linear light sources, screening elements for additional light sources in the form of rectangles, the sides of which are parallel to the axes of the OB, the OS are located at the output ontsah blend of linear light sources on the outer surface of the target set photodetector electrically connected to the light source control unit, all of the target surface are covered with a material with high light absorption coefficient.

The technical result is achieved by ensuring the possibility of using the device in the motion control system of an active spacecraft when performing operations to control the relative orientation of the active and passive spacecraft under any lighting conditions on both the day and night sides of the orbit.

The essence of the invention is illustrated by graphic materials:

FIG. 1 is a diagram of the proposed device;

FIG. 2 - section D-D;

FIG. 3 - section EE;

FIG. 4 is a view of the image on the operator’s monitor when the docking target is rotated in the AOS plane around the axis of the OB;

FIG. 5 is a diagram of an experimental setup;

FIG. 6 - television images of the current layout of the target dock.

The list of positions:

1 - disk light source,

2 - the first linear light source,

3 - the first additional light source,

4 - the second additional light source,

5 - the second linear light source,

6 - the third additional light source,

7 - the fourth additional light source,

8 - photosensor,

9 - light source control unit,

10 - a hood for a disk light source,

11 - the inner ring with an absorbing coating,

12 - outer ring with a reflective coating,

13 - the base of the target,

14 - hood of the first linear light source,

15 is a screening element for a first additional light source,

16 is a screening element for a first linear light source,

17 is a screening element for a second additional light source,

18 - a hood of a second linear light source,

19 is a shielding element for a third additional light source,

20 is a shielding element for a fourth additional light source,

21 is a shielding element for a second linear light source,

22 is an operator monitor screen,

23 - personal computer

24 - television camera

25 - current layout of the target docking,

26 is a laboratory power source,

27 - LED headlight

28 - lamp "MARS-500",

29 - turntable,

30 - background

A - axis OA of the target of the docking (axis of sight),

B - axis OB of the target of the docking,

C is the axis of the OS of the docking target.

The docking target is mounted on the passive spacecraft body on the outside near the docking port so that the axis OA of the docking target is parallel to the axis OX of the spacecraft. Based on the 13th target in the OVS plane, there are light sources: a disk light source 1 - at the beginning of the OAWS coordinate system, the first linear light source 2, coinciding with the axis of the OB, the second linear light source 5, coinciding with the axis of the OS, additional light sources: the first 3 and the second 4 are located on a line perpendicular to the axis of the OB and passing through the center of the linear light source 2, and the third 6 and the fourth 7 are located on the line perpendicular to the axis of the OS and passing through the center of the linear light source 5. Lens 10 for a disk source with Veta 1, together with the hole in the inner ring with an absorbing coating 11, determines the angular size of the cone of the radiation field for the disk light source 1. This angle is 2α ≈ 3 ° (determined by the maximum permissible angle of misalignment of the axes in the final section of the approach of two spacecraft at a distance of ~ 3 m) . The disk light source 1 together with the hood 10 is designed to control the alignment of the axes of the approaching spacecraft. The outer ring 12 with a reflective coating is designed to quickly detect the location of the disk light source 1. With zero mismatch, the axis of the disk light source 1 coincides with the axis of view of the television docking camera located on the active SC. In FIG. 4 shows the image on the operator’s monitor when the mismatch angle is ~ 2 ° and the disk light source 1 is almost completely shielded by the ring elements 11, 12. The symmetrical position of the image of the disk light source 1 relative to the horizontal axis of the images of the ring elements 11, 12 indicates that the turn The target was in the AOS plane around the axis of the target. The hood 14 together with the shielding elements 15, 16, 17 determine the shape and angular dimensions of the radiation field of a linear light source 2 located along the axis OB, as well as the first 3 and second 4 additional light sources. The hood 18 together with the shielding elements 19, 20, 21 determine the shape and angular dimensions of the radiation field of the second linear light source 5, as well as the third 6 and fourth 7 additional light sources. In FIG. Figure 4 shows that the images of the first linear light source 2 and the first additional light source 3 are not covered by images of the shielding elements 15 and 16. This indicates that the target was rotated around the axis OB in the AOS plane counterclockwise. If the turn were made clockwise, then in FIG. 4, the image of the first linear light source 2 and the second additional light source 4 would be visible. If the axes coincide, the linear light sources 2 and 5 are completely blocked by the shielding elements 16 and 21, and the additional light sources 3, 4, 6, 7 are completely blocked by the shielding elements 15 , 17, 19, 20. The length of the visible image of the linear light source 2 depends on the mutual rotation angle of the axis OA of the target and the axis of sight of the television camera in the AOS plane. The angle β shown in section EE in figure 3 is determined from the expression:

where b is the width of the shielding element 16,

h is the height of the hood 14.

If the line of sight of the television camera deviates from the target axis by the angle β _EE , only half of the linear light source 2 will be visible on the operator’s monitor on the target image, the second half of the source will be covered by a shielding element 16. An additional light source 3 will also be visible on the television image, since when the angle of deviation of the line of sight is equal to β _EE , the screening element 15 does not overlap the rays from an additional light source 3. For other sections, expression (1) is converted to:

where k is the ratio of the length of the visible part of the linear light source to its total length. For small deviation angles (β≤4 ° ≈ 0.07 rad), expression (2) is transformed to:

с помощью линейных источников света оператор будет определять только направление угла отклонения от оси, а значение угла отклонения от оси визирования по положению центра изображения кольца 12 с отражающим покрытием относительно центра телевизионного изображения на мониторе оператора. Угол γ между осями ОВ, ОС и соответствующими длинными сторонами экранирующих элементов 16 и 21 линейных источников света 2 и 5, определяется из выражения:At deflection angles

using linear light sources, the operator will only determine the direction of the angle of deviation from the axis, and the value of the angle of deviation from the axis of sight by the position of the center of the image of the ring 12 with a reflective coating relative to the center of the television image on the operator’s monitor. The angle γ between the axes OB, OS and the corresponding long sides of the shielding elements 16 and 21 of the linear light sources 2 and 5, is determined from the expression:

where l is the length of the linear light source. For small angles γ (γ≤5 °), expression (4) is reduced to the form:

For the lower edge of the hood, 14 k = 1. Substituting b from expression (3) into (5), we obtain:

Thus, expression (6) determines the relationship between the design parameters of the target h, l, γ and the boundary of the range of measured angles β _{k = 1} using linear light sources 14, 18.

A photosensor 8 located on the outer surface of the light source control unit 9 is designed to measure the level of external illumination of the target. The signal from the photo sensor 8 enters the control unit of the light sources 9, which is made, for example, as a pulse-width modulator (PWM), which controls the duration of the pulses for switching on the light sources of the target, made, for example, based on adjustable LED emitters. The adjustment characteristic is calculated so that the brightness of the light sources averaged over the period of modulation increases with an increase in the background illumination of the target and decreases with a decrease in the background illumination. This allows the television camera docking with a CMOS-type matrix and automatic exposure control to provide a target image without the effect of dazzling the matrix. To increase the absorption coefficient and eliminate spurious reflections, all surfaces of the target, except for the surface of the outer ring 12 with a reflective coating made, for example, based on reflectors or reflective microprisms, are coated with a material with a high absorption coefficient, for example, foamed aluminum plates with pore sizes ~ 0.1 ÷ 0.5 mm and having a black matte finish. It is possible to use more efficient absorbing materials, for example, based on nanotubes, in the presence of technological processes for their production.

To test the feasibility of the invention in terms of the ability to work with the target, both in daytime and at night with light from the LED headlight, a laboratory experimental setup was created, the circuit of which is shown in FIG. 5. The current model of the target 25, recorded from the laboratory power source 26, is mounted on the turntable 29 at a distance of ~ 5 m from the television camera 24 connected to the personal computer 23. The lighting situation, close to sunlight, was created using a MARS type lamp -500 ”, installed at a distance of ~ 0.5 m from the current layout of target 25 and LED headlight 27 mounted on a stand near the television camera 24. To simulate lighting conditions on the night side of the orbit, only the todiodnaya lamp 27, and to simulate solar illumination lamp "MARS-500 'is further included the target 28. The layout 28 is mounted in front of the television camera 27. Mismatch axes in the horizontal plane is made by means of the turntable 29.

. Освещенность от фары изменяется обратно пропорционально отношению квадратов расстояний до мишени, а освещенность от Солнца неизменна. Поэтому для дистанции 30 м отношение дневной освещенности к ночной будет в

раз больше, т.е. 3600. При контроле оператором взаимной ориентации мишени на пассивном КА и телевизионной камеры на активном КА в процессе сближения и стыковки оператору необходимо отчетливо видеть изображение не только мишени, но и окружающие элементы конструкции пассивного КА, с которым производится сближение. Поэтому телевизионная камера подстраивается под средний уровень яркости в кадре. При переходе с дневной стороны орбиты на ночную, если не изменять яркость источников света мишени, их яркость на несколько порядков превысит порог насыщения приемника телевизионной камеры и работа по такому изображению будет некомфортна, либо невозможна. Для решения этой проблемы предназначен блок управления источниками света 9. Фотодатчик 8, установленный на внешней поверхности мишени, измеряет уровень внешней освещенности на поверхности мишени. Фотодатчик 8 имеет связь с блоком управления источниками света 9, который выполняет регулирование яркости источников света, чтобы она не превышала уровень насыщения приемника телевизионной камеры стыковки, а контраст яркости источников света и фона макета мишени стыковки был комфортным для наблюдения.In FIG. 6 presents images obtained in a laboratory experimental setup. The two upper images correspond to zero mismatch between the axes of the camera 24 and the layout of the target 25, since the image of the disk light source 1 is in the center of the ring with a reflective coating 12. The upper left image corresponds to the conditions of daylight sunlight. This can be seen from the shadow cast from the layout of target 25 on a white background 30 with the MARS-500 lamp 28 turned on. In the upper right image, the MARS-500 lamp 28 is turned off, which is visible by the absence of shadow from the layout of target 25, but the LED headlight 27, this can be seen by the shadow on a white background from the turned off lamp "MARS-500" 28. In the lower two images, the lighting conditions are the same as the upper ones. But the layout of the target 25 is rotated around the axis of the OB clockwise (if viewed from top to bottom) in the horizontal plane at an angle of ~ 4 °. This is evidenced by the complete shielding of the disk light source 1, as well as the absence of shielding of the first linear light source 2 and the first additional light source 3. Partial shielding of the first linear light source 2 in the form of reducing the length of its image on the operator’s monitor screen is proportional to the angle of rotation around the vertical axis . The illumination from the MARS-500 28 lamp on the surface of the target 25 layout was -120000 lux, and from the LED headlight 27, with the MARS-500 28 lamp turned off, it was -1200 lux (for a distance of 5 m). Thus, the ratio of daylight to night for this distance is

. The illumination from the headlight varies inversely with the ratio of the squares of the distances to the target, and the illumination from the Sun is unchanged. Therefore, for a distance of 30 m, the ratio of daylight to night will be in

times more i.e. 3600. When the operator controls the relative orientation of the target on the passive spacecraft and the television camera on the active spacecraft in the process of approaching and docking, the operator must clearly see the image not only of the target, but also the surrounding structural elements of the passive spacecraft with which it is approaching. Therefore, the television camera adjusts to the average brightness level in the frame. When switching from the day side of the orbit to the night one, if the brightness of the target light sources is not changed, their brightness will exceed the saturation threshold of the receiver of the television camera by several orders of magnitude and working on such an image will be uncomfortable or impossible. A light source control unit 9 is designed to solve this problem. A photosensor 8, mounted on the outer surface of the target, measures the level of external illumination on the surface of the target. The photosensor 8 is in communication with the light source control unit 9, which controls the brightness of the light sources so that it does not exceed the saturation level of the receiver of the television docking camera, and the contrast of the brightness of the light sources and the background of the layout of the docking target is comfortable for observation.

The proposed device can be used as a docking target in the motion control system of both manned spacecraft and cargo cargo spacecraft to provide a teleoperator control mode (TORU).

Claims (1)

A device for controlling the orientation of spacecraft during approach, containing a target with light sources, characterized in that at the beginning of the OAVS coordinate system of the target there is a disk light source with an axis of radiation coinciding with the OA axis, equipped with a hood, the output end of which is bordered by two rings - the inner one with a high absorption coefficient and external with a high reflection coefficient, along the axis of the OB and OS are linear light sources equipped with hoods, at the output ends of which are shielding elements s are in the form of parallelograms, the planes of which are parallel to the OVS plane, with the long sides of the parallelograms having an acute angle with the OV and OS axes, additional light sources are located in the OVS plane inside the blend of linear light sources on lines perpendicular to the OV and OS axes and passing through the centers of linear sources light shielding elements for additional light sources in the form of rectangles, the sides of which are parallel to the axes of the OB and OS, are located at the output ends of the blends of linear light sources, on the outer On the surface of the target, a photo sensor is installed, electrically connected to the light source control unit, all surfaces of the target are coated with a material with a high light absorption coefficient.

Images