JP2003306200A - Image navigation for rendezvous docking and navigation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image navigation for a rendezvous docking and navigation device allowing a non-cooperative target satellite having no special marker launched in the past to effectively navigate at rendezvous docking (RVD) by moving a service satellite so as to approach a place, as a target, having an annular satellite-common structure such as a satellite frame part of a target satellite and corresponding to an object portion to be docked. <P>SOLUTION: Image of the target satellite 2 is picked up including the satellite frame part 21 by the service satellite 1, relative distance between the service satellite 1 and the target satellite 2 is measured, relative position of the satellite frame part 21 for the service satellite 1 is calculated, and the satellite frame part 21 in the picked up image is recognized as at least either an ellipse or a circular arc. Thereby, relative attitude of the satellite frame part 21 for the service satellite 1 is calculated, and the service satellite 1 is moved so as for the satellite frame part 21 in the picked up image to be close to a circle on the basis of the calculated relative position and relative attitude. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to, for example, a rendezvous docking (RVD: Rendezvous) satellite on an orbit.
Near-range navigation sensor (NRS: Near-r) for approaching during RVD of a spacecraft that performs docking) to maintain the satellite.
The present invention relates to an image navigation and navigation device for rendezvous docking, which can stably move even to an artificial satellite that does not have a target marker dedicated to docking that has been launched in the past.

[0002]

2. Description of the Related Art In recent years, since the orbital congestion of artificial satellites is becoming a problem, rendezvous docking to an artificial satellite (target satellite) already in orbit, maintenance of the target satellite, and maintenance of the target satellite Realization of a so-called "service satellite", which is an artificial satellite for extending or discarding the target satellite out of orbit, is desired.

A conventional service satellite is provided with gripping means such as a gripping hand and a gripping arm on the docking side,
The holding means holds the frame portion (satellite frame portion) of the target satellite as described above to perform docking with the target satellite. The satellite frame portion is a short cylindrical portion provided as a common structure of the artificial satellite for mechanical connection with the launch mother ship.

Further, when approaching the target satellite on the premise of such docking, the service satellite aims at a marker formed of a dedicated reflector or the like provided on the docking side of the target satellite. Specifically, the service satellite captures an image including the above-mentioned marker with an imager included in the service satellite, performs image processing on the imaged result, calculates the relative position and relative attitude with the target satellite, and based on the calculated result. Then, the aircraft approaches the target satellite so that the surfaces on the docking sides face each other.

[0005]

However, the target satellites in the past, which have already been launched into the satellite orbits, do not have such a dedicated marker, so the above-mentioned navigation is performed in the past. Application to target satellites (so-called non-cooperative target satellites) is virtually impossible.

The invention of the present application has been made in view of the above situation, and an approach is aimed at a portion having a ring-like satellite common structure such as a satellite frame portion of a target satellite and corresponding to a docking target portion. As described above, by moving the service satellite, an image navigation and navigation device for rendezvous docking that can effectively perform navigation during rendezvous docking even for non-cooperative target satellites launched in the past is provided. The purpose is to

[0007]

The present invention can solve the above problems by an image navigation and navigation device for rendezvous and docking having the following configurations.

The image navigation for rendezvous docking according to the present invention is the image navigation for rendezvous docking in which the spacecraft is moved to a docking target portion of the artificial satellite in order to rendezvous dock the spacecraft with the artificial satellite. Based on the first step of imaging the artificial satellite including its annular frame structure by the spacecraft, the second step of measuring the relative distance between the spacecraft and the artificial satellite, and the measured relative distance. A third step of calculating the relative position of the annular frame structure to the spacecraft, and recognizing the annular frame structure in the captured image as at least one of an ellipse and an arc, A fourth step of calculating the relative attitude, and the calculated relative position and phase of the annular frame structure. Based on the attitude, such that the annular frame structure in the captured image approaches a circle, and having a fifth step of moving the spacecraft.

The rendezvous docking image navigation apparatus according to the present invention is a rendezvous docking image navigation system that moves the spacecraft to a docking target portion of the artificial satellite in order to rendezvously dock the spacecraft with the artificial satellite. In the device, a first imager provided in the spacecraft and configured to image the artificial satellite including its annular frame structure, and a relative distance between the spacecraft and the artificial satellite based on a relative distance between the spacecraft and the artificial satellite. By calculating the relative position of the annular frame structure and recognizing the annular frame structure in the image captured by the first imager as at least one of an ellipse and an arc, the relative attitude of the annular frame structure with respect to the spacecraft is determined. Based on the calculated relative position and relative attitude, the annular frame in the image captured by the first imager is calculated. As over arm structure approaches a circle, characterized in that it comprises a computer to move the spacecraft.

According to the above invention, the spacecraft does not target the dedicated marker of the artificial satellite (that is, the target satellite) to be docked as in the conventional case, but the annular frame exposed on the surface of the target satellite. Approach with structure as the goal. Specifically, an imager (first imager) included in the spacecraft captures an image of the ring frame structure of the target satellite, and image processing is performed on the image pickup result to determine the relative position between the ring frame structure and the spacecraft. The relative attitude (that is, the relative position and relative attitude between the target satellite and the spacecraft) is calculated so that the annular frame structure in the captured image approaches a circle, that is, the first imager faces the annular frame structure. As such, it is to move the spacecraft.

As the annular frame structure, it is desirable to use an annular satellite frame portion for connecting the launch satellite of the target satellite. Such a satellite frame part is one that an artificial satellite has as a common structure on its outer surface, and especially during rendezvous docking, this satellite frame part becomes the docking target part, so Is suitable as More specifically, it is desirable to move the satellite frame so that the center of the imaging range coincides with the center of the imaging range. In this case,
It is desirable that the image pickup device is arranged at a position of the spacecraft such that its optical axis finally coincides with the center of the docking target portion.

As for image processing, general ellipse recognition processing and / or arc recognition processing can be used. Since the annular frame structure included in the captured image appears as an ellipse or a part thereof, or a circle or a part thereof, from such a shape, the relative position and relative attitude of the annular frame structure, and by extension, the relative position of the target satellite. And the relative attitude can be obtained.

However, the spacecraft rarely faces the target satellite at the beginning of the approach for rendezvous docking, and thus the annular frame structure in the captured image often appears as an elliptical shape. Therefore, the annular frame structure in the captured image is often shielded by a large number of satellite-specific auxiliary devices provided on the outer surface of the target satellite, and also has a strong optical reflection that covers the main body of the target satellite. Protective film with characteristics (so-called ML
I: Multi Layer Insulator) causes halation by reflected light, so it may be difficult to extract the annular frame structure from the captured image.

Therefore, in the present invention, the ellipse recognition method (Ell recognition method disclosed in Japanese Patent Application No. 2001-010828 by the applicant of the present application)
By using ipse-Fit), the relative position of the annular frame structure and the relative position of the annular frame structure are extracted from the extracted image of the elliptical annular frame structure that is partially missing due to being shielded by auxiliary devices or causing halation. It is possible to efficiently obtain the relative attitude.

Generally, in the ellipse recognition method, the relative orientation of the target circular object can be generally obtained from the recognized ellipse.
It is not possible to determine which direction the center axis of the ellipse faces. Therefore, in order to compensate for this part, by measuring the relative position (or relative distance) of an arbitrary point (for example, the center of the ellipse or a plurality of points on the ellipse) in the plane through which the recognized ellipse passes, It is possible to specify the relative attitude. Further, the orientation direction of the ellipsoid can hardly be inverted during the processing in the application of the present invention, so it is sufficient to once recognize which direction, for example, a human can judge only that portion from the captured image. Then, it is also possible to manually input to the device according to the present invention. Note that this also applies to the arc recognition method.

Further, since the circular arc recognition processing is used when the target circular object is substantially directly facing the image pickup device, it is not always necessary to obtain the relative posture. This is because the satellite frame part is facing 180 ° oppositely as described above,
This is because it is blocked by the main body of the target satellite and cannot be captured by the imager. Therefore, in the arc recognition processing, at least the relative position and particularly the center position of the recognized arc should be obtained. However, as a matter of course, the relative attitude may be obtained in parallel by the arc recognition processing.

In order to obtain the relative position of the annular frame structure, it is necessary to obtain the relative distance of a specific position (for example, the center position or the position on the ellipse or arc) of the annular frame structure. It is possible to provide a plurality of image pickup devices on a spacecraft and perform stereo measurement with these plural image pickup devices. Further, it is also possible to measure the relative distance by optical cutting by irradiating slit light such as laser light having relatively high brightness so as to traverse the annular frame structure. In general, since the light-slit measurement using laser slit light can improve the ranging accuracy more than the stereo measurement, for example, the stereo measurement is performed when the relative distance is long, and the light-disconnection measurement is performed when the relative distance is close. You may make it apply.

Further, the slit light as described above is irradiated so that the light reflected by the annular frame structure and the surrounding MLI is imaged by at least one of the plurality of image pickup devices,
It is also possible to set the reflected slit light to be imaged so as to come to a predetermined position in the imaging range when the relative distance becomes a predetermined distance. In this case, the predetermined position of the imaging range is made to coincide with the gripping position of the gripping means such as the gripping hand and the gripping arm of the spacecraft, while the irradiation position of the annular frame structure (that is, the reflection position) is It is desirable that the position of the target satellite exactly coincides with the position of the target to be grasped. In addition, not only the relative distance but also the relative attitude may be obtained by using the light section measurement. For example, it is possible to obtain the relative distances of a plurality of places (for example, three places) on the annular frame structure by optical cutting measurement, and obtain the relative posture of the annular frame structure from the obtained relative distances of the respective places.

As described above, the image pickup device is necessarily installed in the spacecraft due to its structure, but at least 2 for stereo measurement.
Since one image pickup device is required, the image pickup device is separated from the image pickup device (first image pickup device) arranged in the center of the docking side surface of the spacecraft and the image pickup device provided separately from the first image pickup device. Image pickup device (second image pickup device), or a plurality of second image pickup devices.

In addition to the stereo measurement application, the second
It is desirable that the imager be installed at a position where the optical cutting measurement described above can be easily performed, for example, by installing the imager at a position directly facing the gripping target portion of the target satellite during docking. In such a case, for example, it is possible to dispose the first image pickup device in the center and dispose the second image pickup devices on the orthogonal axes whose intersections are the installation positions thereof.

By arranging a plurality of image pickup devices in this way and performing the above-described stereo measurement, ellipse recognition processing, arc recognition processing, optical cutting measurement, etc., the accuracy of measurement and processing can be improved. There is also an advantage that you can.

In the above invention, the moving object is not limited to the artificial satellite such as the service satellite, but can be applied to various space vehicles launched into outer space using a rocket or the like.

In the rendezvous docking image navigation apparatus according to the present invention, a portion other than the image pickup device or means for irradiating slit light in addition to the image pickup device is configured separately from the spacecraft, and the spacecraft is remotely operated. It is also possible to configure so as to perform the navigation calculation of the above, or to perform only the calculation using the image processing as described above and cause another device to perform the actual navigation calculation. Furthermore, it is also possible to mount the whole part according to the present invention on a spacecraft provided with a propulsion device for navigation and to autonomously move the spacecraft.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The rendezvous according to the present invention will be described below.
Regarding the device for carrying out image navigation for docking,
A service satellite serving as a spacecraft equipped with the device will be specifically described with reference to the accompanying drawings.

First, the target satellite 2 to be docked by the service satellite 1 which will be described in detail later will be described.
The target satellite 2 of the present embodiment is, for example, as shown in FIG. 1, a docking side of the box-shaped main body 2a covered with MLI and the service satellite 1 (hereinafter, this side is referred to as the front).
, A short cylindrical satellite frame portion 21 provided for connection with the launch mother ship of the target satellite 2 and the main body.
The solar cell panel 22 projects from the side of 2a, and the auxiliary devices 23 provided on each part of the main body 2a so as to be exposed. Further, a substantially conical injection port 23 such as an apogee motor is provided at a central position of the satellite frame portion 21 so as to project from the front surface of the main body 2a with its large diameter side facing forward.

On the other hand, the service satellite 2 according to the embodiment of the present invention has an overall configuration shown in a perspective view in FIG. 2 and a main part of its control system as shown in a block diagram in FIG. The main body 1a has a shape, and the main body 1a has the main camera 11 in the center of the surface on the docking side (hereinafter, this side is the front). The main camera 11 is arranged with its imaging optical axis facing forward. On the front surface of the main body 1a, a total of four sub-cameras 12 are arranged at equal positions above, below, to the left and right of the main camera 11, and are equidistantly spaced from the main camera 11. In the present embodiment, the main camera 11 and the four sub cameras 12 are
They are arranged in the same plane.

The main camera 11 and the sub camera 12 can be adjusted in focus and have a viewing angle (FOV) of about 30.
A monochromatic camera of ° is adopted.

Each sub-camera 12 includes a laser projector 15
Also, it is unitized with the gripping hand 16 and the distance to the main camera 11 can be changed in this unit. The laser projectors 15 corresponding to the upper and lower sub-cameras 12 are offset on the right side in the imaging optical axis direction of the sub-cameras 12, and the left and right sub-cameras 12 are arranged.
The laser projector 15 corresponding to the sub camera 12
Is offset downward in the image pickup optical axis direction. Each laser projector 15 is arranged so as to irradiate the slit-shaped laser light forward with a slight inclination with respect to the image pickup optical axis of the sub camera 12, and the slit direction,
The upper and lower laser projectors 15 are oriented in the vertical direction, and the left and right laser projectors 15 are oriented in the horizontal direction.

On the other hand, each gripping hand 16 has a substantially U-shape, and a U-shaped web portion is provided along the surface on the docking side, and a flange portion having an end effector (not shown) at the tip thereof. Is arranged with the front facing. By operating each gripping hand 16 so as to bend forward at the central portion thereof, the docking target (that is, the satellite frame portion 21) can be gripped at the U-shaped tip portion. There is. Upper and lower gripping hands 16
Are arranged along the up-down direction of the web part, and the left and right gripping hands 16 are arranged along the left-right direction of the web part, whereby the four gripping hands 16 are arranged vertically and horizontally on the satellite frame part 21. It is easy to grasp the four points.

A ring-shaped surface light source (hereinafter, simply referred to as “illumination”) 13 is arranged around the main camera 11 so that the imaging range of the main camera 11 and the sub camera 12 can be illuminated. You can do it. Furthermore, one or more propulsion devices 14 (see FIG. 3) for attitude control of a gas jet or the like are provided at appropriate locations on the main body 1a.

The service satellite 1 according to the present embodiment has the above-described hardware configuration, and as will be described in detail below, the computer 10 (see FIG. 3) included in the service satellite 1
Set the satellite frame part 21 of the target satellite 2 to the main camera 11
Also, the sub camera 12 captures an image, and the captured image is subjected to image processing using the captured image as input information.
The propulsion device 14 is operated with the center of the target as the target, and the target satellite 2 is approached.
Is operated to grip the satellite frame portion 21 of the target satellite 2 to achieve capture and docking.

Information about the target satellite 2 (for example, overall dimensions, dimensions of the satellite frame portion 21, etc.) and information about the installation positions of the main camera 11 and the sub-camera 12 can be obtained in advance. It is stored in a memory (not shown) of the computer 10.

Next, the control contents of the computer 10 of the service satellite 1 at the time of rendezvous docking will be referred to by the images taken by the main camera 11 and the sub camera 12 of FIGS. 7 to 11 according to the flowcharts of FIGS. 4 to 6. While explaining.

First, the main routine will be described with reference to FIG. The service satellite 1 starts an approach to reduce the distance from the target satellite 2, and, for example, when the relative distance from the target satellite 2 reaches about 7500 mm, the computer 10 turns on the illumination 13 (step S1 ), Start imaging with the main camera 11 and the sub camera 12 (step
S2). In this case, the relative distance can be measured by using, for example, radar, GPS, etc.
It is possible to perform the correlation processing of 21 whole shape patterns. Also, here, the start time of the main routine is set to the time when the relative distance becomes about 7500 mm,
The thickness is not limited to this, and may be about 10,000 mm, for example.

FIG. 7 shows a picked-up image 110 by the main camera 11 and picked-up images 121-124 by each sub-camera 12 at about 7500 mm. Where the main camera 11
7, the image taken by the sub camera 12 on the upper side is taken on the upper side of the taken image 110 at the center, and the image taken 122 by the sub camera 12 on the right side in the image taking direction is taken at the center. On the right side of the image 110, the captured image 123 by the sub camera 12 on the lower side is on the lower side of the captured image 110 in the center,
Then, the imaged image 124 by the sub camera 12 on the left side in the imaging direction is arranged on the left side of the imaged image 110 in the center. A cross mark arranged in the center of each of the captured images 110 and 121 to 124 is a center mark O of the main camera 11 and the sub camera 12.

As the service satellite 1 approaches the target satellite 2, the target satellite 2 comes to fit within the imaging range of the main camera 11 and the sub camera 12, and in the captured image, the satellite frame portion 21 of the target satellite 2 generally Appears as an ellipse.

Subsequently, the computer 10 starts the stereo measurement by the sub camera 12 (step S3), executes the ellipse recognition processing routine which will be described in detail later by the sub camera 12 (step S4), and considers the stereo measurement result. Then, the propulsion device 14 is operated so that the satellite frame portion 21 recognized as an ellipse approaches a circle and the imaging optical axis of the main camera 11 coincides with the center axis of the ellipse. This allows each captured image
The target satellite 2 in 110 and 121-124 approaches as shown in FIG. 8, and the satellite frame portion 21 that appears as an ellipse is also shown in FIG.
Closer to a circle than.

As shown in FIG. 1, the satellite frame part
Since the injection port 23 of the apogee motor may be arranged inside 21, it may be mistaken for the satellite frame portion 21, but it is possible to recognize multiple ellipses (or arcs) in this way. In such a case, it can be solved by adopting the ellipse (or arc) on the large side.

A sub camera used for stereo measurement
At least two 12 are required, but in the present embodiment, all four sub-cameras 12 are used.

Then, the computer 10 judges whether or not the relative distance to the target satellite 2 based on the stereo measurement by the sub camera 12 is closer than the first threshold value (for example, about 6000 mm) (step S5), When the relative distance is longer than the first threshold value (“NO” in step S5), the sub camera 12
The execution of the ellipse recognition processing routine is maintained. on the other hand,
When the relative distance becomes closer than the first threshold value (“YES” in step S5), the computer 10 determines from the ellipse recognition processing routine by the sub camera 12 to the ellipse recognition processing routine by the main camera 11 and the sub camera. The parallel processing with the arc recognition processing routine, which will be described in detail later in 12, is executed (step
S6), The propulsion device 14 is operated so that the satellite frame portion 21 recognized as an ellipse and a circular arc approaches a circle further and the optical axis of the main camera 11 coincides with the center axis of the ellipse and the circle.

The relative distance is somewhat close (for example, about
If the distance becomes closer than 6000 mm), as shown in FIG. 9, a part of the satellite frame portion 21 captured by the sub camera 12 will deviate from the imaging range. In this case, it becomes difficult to recognize the ellipse of the satellite frame portion 21 obtained from the images 121 to 124 captured by the sub camera 12. Therefore, the same result can be continuously obtained by switching the processing of the sub camera 12 to the arc recognition processing that can be used even if the satellite frame portion 21 is partially missing from the imaging range.
Further, in the central main camera 11, there is a possibility that the entire part of the satellite frame portion 21 that is closer to the circular shape may still be captured. In that case, the main camera 11 takes over the ellipse recognition processing. Run with. As described above, by performing different recognition processes in parallel in the main camera 11 and the sub camera 12, it is possible to improve the reliability of the obtained recognition result.

The relative distance is even closer (for example, about 3000
10 mm, the satellite frame portion 21 captured by the main camera 11 also partly deviates from the imaging range as shown in FIG. In this case, the satellite frame unit 2 obtained from the image 110 captured by the main camera 11
It becomes difficult to recognize 1 as an ellipse as above. Therefore, the same processing can be continued by switching to the arc recognition processing of only the sub camera 12.

Therefore, the computer 10 determines that the relative distance is the second.
It is judged whether or not it is closer to a threshold value (for example, about 3000 mm) (step S7), and if the relative distance is longer than the second threshold value ("NO" in step S7), the main camera 11 recognizes an ellipse. The execution of parallel processing between the processing routine and the arc recognition processing routine by the sub camera 12 is maintained. On the other hand, when the relative distance is closer than the second threshold (step
To "YES" in S7), the computer 10 shifts from the parallel processing of the ellipse recognition processing routine by the main camera 11 and the arc recognition processing routine by the sub camera 12 to the arc recognition processing routine by the sub camera 12 (step S8). ), The propulsion device 14 is operated so that the satellite frame portion 21 recognized as an arc further approaches the circle and the optical axis of the main camera 11 coincides with the center axis of the circle.

When the relative distance becomes smaller than, for example, about 1000 mm, as shown in FIG.
May not be captured by the main camera 11 at all, and the sub-camera 12 may approach a straight line to the extent that arc recognition cannot be performed properly.

Therefore, the computer 10 judges whether or not the relative distance has become shorter than a third threshold value (for example, about 1000 mm) (step S9), and when the relative distance is farther than the third threshold value (step S9). The execution of the arc recognition processing routine by the sub-camera 12 is maintained in "NO" in S9. On the other hand, when the relative distance is closer than the third threshold value (step S9
To "YES"), the computer 10 turns on the four laser projectors 15 (step S10), and shifts from the arc recognition processing routine by the sub camera 12 to the light section measurement by the sub camera 12 (step S11). The propulsion device 14 is operated so that the center position of the satellite frame portion 21 in the thickness direction coincides with the center position of the imaging range of the sub camera 12. At this time, the plurality of sub-cameras 12 optically cut the relative distances between the corresponding satellite frame portions 21, identify the relative attitude of the satellite frame portions 21 based on the measurement results, and control the attitude. Is also possible.

The laser slit light 150 emitted from each laser projector 15 is regarded as a substantially circular shape (more precisely, a part thereof) at this point in the satellite frame portion.
Irradiation is performed in the normal direction of 21 so as to cross the satellite frame portion 21, and in the present embodiment, the relative distance is about 0 m.
The irradiation angle of each laser projector 15 is set so that the laser slit light 150 irradiated to the end surface (called “flange surface”) of the satellite frame portion 21 coincides with the center mark O when the m is reached. .

The computer 10 determines that the relative distance is the fourth.
It is judged whether or not the distance is closer than a threshold value (for example, about 100 mm) (step S12), and when the relative distance is farther than the fourth threshold value ("NO" in step S12), the optical disconnection by the sub camera 12 is performed. Keep the measurement run. On the other hand, when the relative distance is closer than the fourth threshold value ("YE" in step S12).
In S "), the computer 10 operates the four gripping hands 16 (step S13), grips the gripping target portion of the satellite frame portion 21, and completes the docking with the target satellite 2.
The fourth threshold value is set in consideration of the operating speed of the gripping hand 16, the propulsion speed of the service satellite 1, and the like.

When the relative distance reaches the fourth threshold value, the center position in the thickness direction of the satellite frame portion 21 captured by each sub camera 12 is made to coincide with the center position of the imaging range of each sub camera 12. In order to do this, the main camera of the sub camera 12 is arranged with the main camera 11 as the center.
It is necessary to match the distance from 11 with the radius of the satellite frame portion 21. Therefore, at the time of rendezvous docking, the dimension information of the satellite frame portion 21 of the target satellite 2 is acquired in advance, and the sub camera 11 is based on the dimension information.
It is also possible to set the position of the sub-camera 12, and it is also possible to dynamically change the position of the sub-camera 12 while approaching the target satellite 2.

In the above flowchart, the recognition processing is switched according to the measured relative distance, but the present invention is not limited to this. For example, the satellite frame unit 21 captured by the main camera 11 or the sub camera 12 is used.
It is also possible to recognize that a part of the image data deviates from the respective imaging ranges and use this as a switching trigger.

The values of the respective thresholds are merely examples, and these may be set appropriately in consideration of the resolution of each camera, the distance measuring accuracy, and the like.

Next, the ellipse recognition processing routine is shown in FIG.
Will be described in detail with reference to. In the ellipse recognition processing routine,
First, the computer 10 extracts an edge segment from a grayscale image as a captured image (step S101).

The computer 10 calculates, for example, the position of each edge segment and the normal vector of each edge segment obtained from the density gradient in each edge segment, and the edges of which the directions of the normal vector differ by 180 degrees The point symmetry of the edge segment is determined by finding the pair of segments (step S102). Here, the midpoint position of the obtained edge segment pair is a candidate for the ellipse center position.

Next, the computer 10 changes the angle of the axis passing through the point symmetry center position, which is the above-mentioned middle point position, and, for example, the edge segment existing facing the position equidistant from the axis. The line symmetry of the edge segment is determined by finding the pair of (step S103). Here, the inclination of the ellipse axis of the corresponding ellipse with respect to the imaging screen is obtained by the line symmetry axis of the edge segment pair having line symmetry, and thus the orientation of the ellipse is obtained.

Subsequently, the computer 10 extracts an edge segment pair that is point-symmetrical and line-symmetrical, sets the point-symmetrical center position of the edge segment pair as the ellipse center position, and
The axis of line symmetry is set to one of the ellipse axes, and the ellipse axis length is obtained using, for example, Hough transform (step S104).

The computer 10 applies the elliptic parameters thus obtained to the elliptic equation to judge the validity of each parameter, and, for example, the least squares method is used so that the error is sufficiently small. Is corrected (step S105).

The computer 10 uses a plurality of locations (for example,
Three relative positions (which are measured by the above-described stereo measurement, etc.) are obtained, and the relative attitude of the satellite frame unit 21 is calculated from the plurality of relative positions (step).
S106).

Specifically, as shown in FIGS. 7 to 10,
Considering the ellipse (that is, the satellite frame portion 21) in the captured image and the horizontal and vertical axes (stereo measurement lines) 111 and 112 that pass through the satellite frame portion 21 (for example, its center position),
The intersections between the satellite frame portion 21 and the stereo measurement lines 111 and 112 are obtained, and common symbols A to D are assigned.

Here, if the end surface of the satellite frame portion 21 is regarded as a plane, then that plane can be expressed by the following equation.

Ax + by + cz + d = 0 (1) The measurement point at this time is (xi, yi, zi). However, i = A, B, C, D, and points A, B, and
C and D can be obtained by stereo measurement or the like.

Each point A, B, obtained by stereo measurement, etc.
Based on the positions of C and D, the equation of the above plane is determined by solving the simultaneous equations according to the following least squares method,
Therefore, the relative attitude of the satellite frame unit 21 can be obtained.

[0061]

[Equation 1]

The relative distance of the satellite frame portion 21 may be calculated as the positions of points A, B, C and D that may coincide with the grasped part, or the satellite frame in consideration of the obtained relative attitude. It may be calculated as the center position of the section 21.

In the ellipse recognition processing routine, the relative distance of the corresponding pixel (or edge segment) existing on the ellipse according to the obtained ellipse parameter is obtained by stereo measurement. Since the relative posture can be roughly obtained, only the relative position can be independently obtained by using various distance measuring methods such as stereo measurement and optical cutting measurement.

Next, the arc recognition processing routine will be described with reference to FIG.
Will be described in detail with reference to. In the arc recognition processing routine,
First, the computer 10 extracts an edge segment from a grayscale image as a captured image, similarly to the ellipse recognition processing routine (step S201).

The computer 10 sets the relative distance to a certain appropriate value, calculates the normal vector of each edge segment obtained from the density gradient in each extracted edge segment, and calculates the normal vector of the plurality of edge segments. The intersection point position, that is, the arc center position and the arc radius are calculated (step S202). It is possible to shorten the calculation time and improve the recognition accuracy by measuring the relative distance by using various distance measuring methods such as stereo measurement and light cutting measurement.

The control unit 10 calculates the appearance frequency of the calculated arc center position coordinate group (step S203), and when the appearance frequency exceeds a predetermined threshold, sets the corresponding arc center position and arc radius as candidates, By applying this parameter to the circle equation, the validity of each parameter is determined, and for example, the least square method is used to correct the parameter so that the error becomes sufficiently small (step S204).

The computer 10 is based on the position of the arc in each captured image specified from the corrected arc parameter and the actual width dimension (thickness of the tubular portion) of the satellite frame portion 21 that can be acquired in advance. , The relative position of the satellite frame portion 21 is calculated, while at the same time as step S106 of the ellipse recognition processing routine,
The relative attitude of the satellite frame unit 21 is calculated from the relative positions of a plurality of points (for example, three points) on the arc measured by the above-mentioned stereo measurement or the like (step S205).

As described above, it is possible to obtain the relative position and relative attitude of the satellite frame portion 21 by both the ellipse and arc recognition processing routines. However, when the arc recognition processing routine is used alone, the service is The satellite 1 may be used in a state where the docking side of the satellite 1 faces the satellite frame portion 21, and only the relative position may be obtained.

That is, in the present embodiment, FIG.
As shown in, the ellipse recognition processing routine is executed up to about 6000 m, the ellipse and arc recognition processing routine is executed in parallel between about 6000 mm and about 3000 mm, and at this point between about 3000 mm and about 1000 mm. Since it is considered that the docking side of the service satellite 1 faces the satellite frame portion 21 substantially, only the arc recognition processing routine is executed. And about 1000mm
From ~ 0 mm, control is performed by light section measurement.

Next, a navigation experiment result of the service satellite 1 using the rendezvous docking image navigation apparatus according to the present embodiment will be described. In this experiment, the target satellite 2 appearing in the imaged screen is displayed on the computer as a 3D CG (C
omputer Graphics) model, this target satellite 2 was attempted rendezvous docking using the above algorithm.

As conditions for the experiment, as shown in FIG. 13, XYZ coordinates are set, and the main camera 11 is set at the origin.
Was arranged so that its imaging optical axis was oriented in the Y-axis direction. Each of the main camera 11 and the sub camera 12 has a viewing angle set to 60 ° in the horizontal and vertical directions. As lighting, a point light source was placed at the same position as the main camera 11 in order to simplify the experiment, although it was physically impossible, and it was assumed that it was on a nightside orbit without sunlight. Also the main camera
The distance between 11 and each sub-camera 12 was 450 mm.

The target satellites 2 are basically separated from each other by a relative distance D in the Y-axis direction, and a texture imitating MLI is attached to the main body 2a. Further, in reality, the service satellite 1 side equipped with the main camera 11 and the sub camera 12 moves, but in this experiment, the position (x, y, z) and attitude (Rx, Ry) of the target satellite 2 are changed. Each was changed and the measurement error was investigated.

FIG. 14 is an experimental result showing a measurement error (%) with respect to an actual distance (relative distance: mm) to the target satellite 2, and FIG. 15 is a rotation angle (deg) about the X axis of the target satellite 2. ) Is an experimental result showing the measured value (deg) of the target satellite 2 for

According to the stereo measurement according to the present embodiment, there was some recognition failure in the relative distance of about 2300 mm to about 2400 mm, but it was measured almost accurately after the processing was started at about 7500 mm. On the other hand, in the relative attitude, when the attitude around the X axis of the target satellite 2 (that is, the rotation angle Rx) was around 21 °, a slight error was recognized, but the overall good result was obtained. was gotten.

[0075]

According to the image navigation and navigation device for rendezvous and docking according to the present invention, a portion of the target satellite having a ring-shaped satellite common structure such as a satellite frame portion and corresponding to a docking target portion is provided. By moving the service satellite to approach as a target, it is possible to effectively perform rendezvous docking navigation even for non-cooperative target satellites launched in the past.

[Brief description of drawings]

FIG. 1 is a perspective view showing an external configuration of a target satellite that is a rendezvous docking target of a service satellite that is a spacecraft according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an external configuration of a service satellite according to an embodiment of the present invention.

3 is a block diagram showing a configuration of a control system of the service satellite shown in FIG.

FIG. 4 is a flowchart showing a main routine of navigation control according to the present embodiment of the service satellite shown in FIG.

5 is a flowchart showing an ellipse recognition processing routine shown in FIG.

6 is a flowchart showing an arc recognition processing routine shown in FIG.

FIG. 7 is a schematic diagram showing an example of an image captured by each camera of the service satellite according to the embodiment of the present invention.

FIG. 8 is a schematic diagram showing an example of an image captured by each camera of the service satellite according to the embodiment of the present invention.

FIG. 9 is a schematic diagram showing an example of an image captured by each camera of the service satellite according to the embodiment of the present invention.

FIG. 10 is a schematic diagram showing an example of an image captured by each camera of the service satellite according to the embodiment of the present invention.

FIG. 11 is a schematic diagram showing an example of an image captured by each camera of the service satellite according to the embodiment of the present invention.

FIG. 12 is a diagram for explaining switching of processing content according to the relative distance between the main camera and the sub camera in the navigation control shown in FIG.

FIG. 13 is a diagram for explaining experimental conditions for navigation control according to the embodiment of the present invention.

FIG. 14 is a graph showing an experimental result of navigation control according to the embodiment of the present invention.

FIG. 15 is a graph showing an experimental result of navigation control according to the embodiment of the present invention.

[Explanation of symbols]

1 Service satellite 2 Target satellite 10 calculator 11 Main camera 12 sub camera 13 lighting 14 Propulsor 15 laser projector 16 gripping hand 21 Satellite frame section 121-124 captured images O center mark

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Isao Kono             2-1-1 Sengen Space, Tsukuba City, Ibaraki Prefecture             Development Agency Tsukuba Space Center (72) Inventor Yoshiyuki Ishijima             2-1-1 Sengen Space, Tsukuba City, Ibaraki Prefecture             Development Agency Tsukuba Space Center (72) Inventor Atsushi Yokoo             118 Futatsuka, Noda City, Chiba Prefecture Kawasaki Heavy Industries             Noda Factory Co., Ltd. (72) Inventor Masayuki Enomoto             118 Futatsuka, Noda City, Chiba Prefecture Kawasaki Heavy Industries             Noda Factory Co., Ltd. (72) Inventor Takao Kanamaru             118 Futatsuka, Noda City, Chiba Prefecture Kawasaki Heavy Industries             Noda Factory Co., Ltd. (72) Inventor Nobuyuki Kubota             Kawasaki Town, Kakamigahara City, Gifu Prefecture Kawasaki Heavy Industries             Gifu Factory Co., Ltd. F-term (reference) 5L096 AA03 CA05 EA27 FA04 FA06                       FA10 FA24 FA62 FA64 FA66                       FA67 FA69 GA32 GA51

Claims (14)

[Claims] 1. An image navigation for rendezvous docking, in which the spacecraft is moved to a docking target part of the artificial satellite in order to rendezvously dock the spacecraft with the satellite. A first step of capturing an image including a frame structure; a second step of measuring a relative distance between the spacecraft and the artificial satellite; and a second step of measuring the relative distance between the spacecraft and the artificial satellite, based on the measured relative distance. A third step of calculating a relative position, and a fourth step of calculating a relative attitude of the annular frame structure with respect to the spacecraft by recognizing the annular frame structure in the captured image as at least one of an ellipse and an arc. Image navigation for rendezvous docking characterized by having. 2. The rendezvous docking according to claim 1, wherein the relative distance and the relative attitude are calculated based on the relative distances of the recognized multiple points of the annular frame structure to the spacecraft. Image navigation. 3. The image navigation for rendezvous docking according to claim 1 or 2, wherein the relative distance is stereo-imaged by a plurality of image pickup devices including the annular frame structure. 4. The relative distance is measured by irradiating slit light so as to traverse the annular frame structure, and performing light section measurement based on an image of the annular frame structure taken together with the irradiation slit light. The image navigation for rendezvous docking according to any one of claims 1 to 3. 5. The fourth step is characterized in that the annular frame structure in images picked up by a plurality of image pickup devices is processed in parallel by both ellipse recognition and arc recognition.
5. The image navigation for rendezvous docking according to any one of 4 to 4. 6. The fourth step comprises: extracting the annular frame structure in a captured image as an edge segment; and selecting a pair from the extracted edge segments whose normal vectors differ from each other by about 180 degrees, and selecting the pair. A step of voting the midpoint of the pair of edge segments in the voting space, and setting the midpoint with a high vote as the point symmetry center; and changing the angle of the virtual line passing through the point symmetry center around the point target center, Selecting an edge segment pair having high line symmetry with respect to an imaginary line, and setting the point symmetry center of the point segment pair that is point symmetric and line symmetric as the ellipse center The parameter of the ellipse to be calculated and the edge segment existing on the ellipse based on the calculated parameter. The method according to any one of claims 1 to 5, further comprising: a step of determining a sex, and a step of calculating a relative posture of the annular frame structure based on an ellipse corresponding to a highly valid parameter. Image navigation for rendezvous docking. 7. An image navigation device for rendezvous docking for moving a spacecraft to a docking target part of the artificial satellite for rendezvous docking with the artificial satellite, wherein the artificial satellite is provided in the spacecraft. A first imager for capturing an image of the ring frame structure including the ring frame structure, and calculating a relative position of the ring frame structure with respect to the spacecraft based on a relative distance between the spacecraft and the artificial satellite. A rendezvous comprising: a computer that calculates the relative attitude of the annular frame structure with respect to the spacecraft by recognizing the annular frame structure in an image captured by one imager as at least one of an ellipse and an arc. Image navigation system for docking. 8. The rendezvous docking according to claim 7, wherein the relative distance and the relative attitude are calculated based on the relative distances of the recognized multiple points of the annular frame structure to the spacecraft. Image navigation device for mobile. 9. The relative distance is adapted to be measured by one or a plurality of second image pickup devices which are provided in the spacecraft and pick up images including the annular frame structure. Or the image navigation device for rendezvous docking according to 8. 10. The relative distance is determined by the first imager and at least one second imager, or a plurality of the second imagers.
10. The image navigation device for rendezvous and docking according to claim 9, wherein the image pickup device is adapted for stereo measurement. 11. The apparatus according to claim 1, wherein four second image pickup devices are provided, and two second image pickup devices are arranged at equal intervals on an orthogonal axis whose intersection is the installation position of the first image pickup device. The image navigation device for rendezvous docking according to claim 9 or 10. 12. The slit light irradiating unit provided in the spacecraft irradiates the slit light so that the relative distance crosses the annular frame structure, and the relative distance of the annular frame structure is imaged together with the irradiation slit light. The image navigation device for rendezvous and docking according to claim 7, wherein the light section measurement is performed based on the image. 13. The computer according to claim 7, wherein the computer is configured to perform parallel processing on the annular frame structure in images picked up by a plurality of image pickup devices by both ellipse recognition and arc recognition. The image navigation device for rendezvous docking described in. 14. The computer comprises means for extracting the annular frame structure in an image captured by the first imager as an edge segment, and a pair of normal vectors of the extracted edge segments that differ from each other by about 180 degrees. A means for selecting the midpoint of the selected edge segment pair in the voting space, and setting the midpoint with a high vote as the point object center, and an imaginary line passing through the point symmetry center with an angle around the point symmetry center. While changing, the means for selecting an edge segment pair having high line symmetry with respect to the virtual line, and the point symmetry center of the edge segment pair that is point symmetric and line symmetric is the ellipse center, while having the ellipse center The means for calculating the parameter of the ellipse passing through the edge segment and the edge segment existing on the ellipse based on the calculated parameter are used to find the compromise of the parameter. Rendezvous Docking image navigation apparatus according to any one of claims 7 to 13, characterized in that it comprises a means for determining the sex.