CN109305394B - Spacecraft close-range rendezvous test simplification method - Google Patents
Spacecraft close-range rendezvous test simplification method Download PDFInfo
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Abstract
The invention relates to a spacecraft close-range rendezvous test simplification method, which comprises the following steps: s1, establishing a relative motion relation between the target device and the tracker; s2, constructing a ground test model; s3, simplifying the test model; and S4, carrying out sensor field verification on the simplified test model. The spacecraft close-range rendezvous test simplification method can solve the problem that relative motion simulation of the spacecraft is difficult in the close-range rendezvous ground test. The in-plane motion of the mass center and the attitude of the spacecraft to be tracked is simplified into the one-dimensional motion of the tracker along a straight line and the superposition of the rotation of the two aircrafts around the respective mass centers. Furthermore, the rotation of the two aircrafts around the respective centroids under the condition that the centroids of the two aircrafts are fixed can be simplified.
Description
Technical Field
The invention belongs to the technical field of rendezvous and docking of spacecrafts, and particularly relates to a close-range rendezvous test method for spacecrafts.
Background
The rendezvous and docking technology refers to the technology that two aircrafts meet at the same time at the same position on a track at the same speed and are structurally connected into a whole. The two aircraft participating in the rendezvous and docking are typically one passive aircraft and one active aircraft. Passive aircrafts do no or little manoeuvre and are called target aircrafts or targets. The active vehicle is to perform a series of orbital maneuvers towards the target, called a tracking vehicle or tracker.
The rendezvous and docking task is generally divided into a long-range guiding section, a short-range guiding section, a translation approaching section and a docking section according to the flight process. And the distance between the two aircrafts at the guidance terminal is one hundred kilometers to dozens of kilometers from the time of tracking the aircraft in the long-distance guidance section to the time of capturing the target by the sensor on the device. The range of the tracking aircraft and the target aircraft varies from a hundred kilometers to several kilometers or hundreds of meters during the short range guidance segment. An important characteristic of the short-range guidance section is that a relative measurement mechanism is established between two aircrafts, and the tracking aircraft can be autonomously controlled without depending on a ground or space-based measurement system.
In the short-range guidance segment, when the distance between the tracker and the target is short (several kilometers to several hundred meters), the relative motion trail and posture of the tracker and the target can be greatly changed in the approaching process due to different docking directions (generally divided into forward, backward and radial docking), and the switching of the rendezvous measurement sensors can be carried out in order to ensure relative navigation. To ensure the matching of the operation of the intersection measuring device between the tracker and the target during this process, and the rationality of the arrangement of the critical flight events, the ground needs to be verified by close-range intersection tests.
During orbital flight, the relative motion of the tracker and the target is controlled by relative navigation during the short-range rendezvous phase, and the motion of the tracker relative to the target can be described as the motion of the mass center of the tracker and the rotation around the mass center. The ground test should simulate the relative motion relationship of the on-orbit flight as much as possible. In the ground test, in order to fully simulate the relative motion characteristic in the on-orbit flight, the ground can be regarded as a track plane, the target keeps static, and the mass center and the attitude of the tracker are controlled by ground test equipment such as a transport vehicle, a tool and the like strictly according to the relative motion relation of the on-orbit, so that the interaction with the target is realized. To implement this solution, it is necessary to ensure that the movement trajectory of the flight tracker on the ground coincides with the on-orbit trajectory, and the following difficulties exist in the operational aspect: firstly, the track of the tracker is not a straight line in the process of approaching the target, and an open field with a flat terrain of several square kilometers is needed during the test, so that the site selection is difficult; secondly, before the test, a relative motion track needs to be drawn on the ground, and in the test, the transport vehicle runs strictly according to the track and the specified speed and is matched with attitude control, so that the operation is difficult.
Disclosure of Invention
The invention aims to provide a spacecraft close-range rendezvous test simplification method, and solves the problem that relative motion simulation of a spacecraft is difficult in a close-range rendezvous ground test.
In order to achieve the above object, the present invention provides a spacecraft close-range rendezvous test simplification method, which comprises:
s1, establishing a relative motion relation between the target device and the tracker;
s2, constructing a ground test model;
s3, simplifying the test model;
and S4, carrying out sensor field verification on the simplified test model.
According to an aspect of the present invention, if the result of the sensor field verification performed on the simplified test model in the step S4 is not within the normal range, the method further includes the step S5: and correcting the test model.
According to one aspect of the present invention, in step S1, it is necessary to determine the sight line vector from the tracker centroid to the target centroid, the longitudinal axis of the tracker body coordinate system, the longitudinal axis of the target body coordinate system, the angle between the tracker longitudinal axis and the sight line vector, and the angle between the target longitudinal axis and the sight line vector.
According to an aspect of the present invention, in the step S2, the ground is used as an orbit plane, and the line-of-sight vector from the centroid of the tracker to the centroid of the target, the angle between the longitudinal axis of the tracker and the line-of-sight vector, and the angle between the longitudinal axis of the target and the line-of-sight vector are adjusted to simulate the actual relative motion between the tracker and the target in orbit.
According to an aspect of the invention, in the step S3, a plurality of feature points are selected on an on-orbit variation curve of the included angle between the longitudinal axis of the tracker and the sight line vector and the included angle between the longitudinal axis of the target and the sight line vector, and the test model is simplified by fitting a piecewise straight line.
According to an aspect of the present invention, in the step S3, the test model may be simplified by fixing the relative distance between the centroid of the target and the centroid of the tracker.
According to an aspect of the present invention, in the step S4, a vector of the target end sensor pointing to the tracker end sensor is obtained according to the sensor coordinates of the target and the tracker, a direction vector of the target end sensor is obtained according to the installation angle, and if an included angle between the vector of the target end sensor pointing to the tracker end sensor and the direction vector of the target end sensor is smaller than the half cone angle of the maximum field of view of the sensor, the verification result is within the normal range.
According to an aspect of the present invention, in the step S5, returning to the step S3, increasing the number of the selected feature points, and repeating the steps S3 to S4 until the verification result is within the normal range.
According to an aspect of the present invention, if the trial model is simplified by fixing the relative distance between the target centroid and the tracker centroid in said step S3, the trial model is modified by adjusting the relative distance between the target centroid and the tracker centroid in S5.
According to one aspect of the invention, a test model of the relative motion during the ground test is constructed by establishing the on-orbit relative motion relationship between the tracker and the target. And fitting the rotation angle curve by using a straight line segment in consideration of the simplicity of the operation of rotating the aircraft cabin around the center of mass. And a method for verifying the rendezvous measurement sensitive field of view is provided, the field of view is verified on the simplified test model, and when the field of view of the simplified test model is inconsistent with that of the in-orbit model, a model correction method is provided for correcting the test model. The method can greatly simplify the test flow, provide test operability and reduce test cost while meeting the requirement of the spacecraft close-range intersection test.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 schematically represents a flow chart of a simplified method for a spacecraft close-up encounter test according to the invention;
FIG. 2 is a schematic representation of the relative position and relative attitude relationships of the tracker and target during close range encounters in accordance with the present invention;
FIG. 3 schematically shows a comparison of ground test and on-orbit flight of a tracker with a target;
FIG. 4 is a schematic representation of the relative movement of the tracker and the target during ground test;
FIG. 5 is a schematic representation of a curve-piecewise linear fit plot;
FIG. 6 is a schematic representation of a field-of-view verification of a measurement sensor in interaction with a target.
Detailed Description
The description of the embodiments of this specification is intended to be taken in conjunction with the accompanying drawings, which are to be considered part of the complete specification. In the drawings, the shape or thickness of the embodiments may be exaggerated and simplified or conveniently indicated. Further, the components of the structures in the drawings are described separately, and it should be noted that the components not shown or described in the drawings are well known to those skilled in the art.
Any reference to directions and orientations to the description of the embodiments herein is merely for convenience of description and should not be construed as limiting the scope of the invention in any way. The following description of the preferred embodiments refers to combinations of features which may be present independently or in combination, and the present invention is not particularly limited to the preferred embodiments. The scope of the invention is defined by the claims.
As shown in fig. 1, the simplified method for the spacecraft close-range rendezvous test of the invention comprises the steps of S1, establishing a relative motion relationship between a target and a tracker; s2, constructing a ground test model; s3, simplifying the test model; and S4, carrying out sensor field verification on the simplified test model.
According to the spacecraft close-range rendezvous test simplification method, a test model of relative motion during ground test is constructed by establishing the in-orbit relative motion relation of the tracker and the target. And fitting the rotation angle curve by using a straight line segment in consideration of the simplicity of the operation of rotating the aircraft cabin around the center of mass. And a rendezvous measurement sensitive field-of-view verification method is provided, and field-of-view verification is performed on the simplified test model. The requirement of a spacecraft close-range rendezvous test is met, the test flow can be greatly simplified, and the test operability is improved.
In the present invention, if the sensor field of view verification performed on the simplified test model is not within the normal range in step S4, the method of the present invention further includes step S5, in which the test model is modified.
The steps of the present invention are described in detail below:
in step S1, it is necessary to determine the sight line vector from the tracker centroid to the target centroid, the longitudinal axis of the tracker body coordinate system, the longitudinal axis of the target body coordinate system, the included angle between the tracker longitudinal axis and the sight line vector, and the included angle between the target longitudinal axis and the sight line vector, so as to establish the relative motion relationship between the tracker and the target.
In step S2, the ground is used as an orbit plane, and the sight line vector from the centroid of the tracker to the centroid of the target, the angle between the longitudinal axis of the tracker and the sight line vector, and the angle between the longitudinal axis of the target and the sight line vector are adjusted to simulate the on-orbit actual relative motion of the tracker and the target.
And step S3, selecting a plurality of characteristic points on an on-orbit change curve of the included angle between the longitudinal axis of the tracker and the sight line vector and the included angle between the target and the sight line vector, and fitting by using a segmented straight line to simplify the test model. In step S3, the test model may also be simplified by fixing the relative distance between the target centroid and the tracker centroid.
And step S4, obtaining a vector of the target end sensor pointing to the tracker end sensor according to the sensor coordinates of the target and the tracker, obtaining a direction vector of the target end sensor according to the installation angle, and if the included angle between the vector of the target end sensor pointing to the tracker end sensor and the direction vector of the target end sensor is smaller than the half cone angle of the maximum field of view of the sensor, determining that the verification result is in a normal range.
If the verification result is not within the normal range as verified in step S4, step S5 is performed to correct the test model. Specifically, the method returns to the step S3, increases the number of the selected feature points, and repeats the steps S3 to S4 until the verification result is within the normal range.
If the trial model is simplified by fixing the relative distance between the target centroid and the tracker centroid in step S3, the trial model is corrected by adjusting the relative distance between the target centroid and the tracker centroid in step S5.
The steps of the simplified method for spacecraft close-range crossing test of the invention are explained in detail by the specific examples.
S1, establishing the relative motion relationship between the target device and the tracker
Let the target centroid be o, as shown in FIG. 21Tracker centroid is o2The line of sight vector from the tracker centroid to the target centroid is r. Then o1x1Is a longitudinal axis of the space station body under the sitting system, and has an included angle theta with r1；o2x2Is the longitudinal axis of the airship body in a coordinate system, and1x1is theta2And the angle with r is theta3. Neglecting the difference of the orbit surfaces, the relation between the relative position and the relative attitude of the tracker and the target in the same plane can be used as theta1、θ3And r are fully described in 3 variables. Obviously, r is the relative distance between the two aircraft, θ1Elevation angle, θ, of flight of the tracker looking at the target2For tracker pitch angle, theta3＝θ1-θ2。
S2, constructing a ground test model
Referring to FIG. 3 and FIG. 4, in the ground test, the ground is regarded as the track plane, and θ is adjusted1、θ 33 variables in total with r can be completely simulatedThe tracker and the target device actually move relatively in the orbit. The tracker does not need to move on the ground along a curved path of on-orbit flight, and only needs to move along a straight road, so that the direction of the vector r is fixed and is superposed with the test road. Fixing the centroid of the target device, and adjusting the relative distance r between the two aircrafts through the linear motion of the tracker along the test road; by adjusting theta1、θ3And realizing the relative posture and orientation of the tracker and the target device. Thus, it is only necessary to secure the relative distances r and θ in the ground test1And theta3According to the change of the rule when flying on the rail, the ground can completely reproduce the relative motion state of the flying on the rail.
During operation, the target device is fixed, and the cabin body can rotate around the mass center through the air floating platform; the tracker is carried on by the transport vechicle, through the motion of transport vechicle simulation barycenter, through the revolving stage simulation every single move on the transport vechicle. If the road length is limited and is not enough to simulate the actual relative distance, the relative distance r can be appropriately shortened in the test. In addition, r may also be set to a fixed value for simplicity of the experiment. Simulation results show that when the relative distance is in the order of hundreds of meters instead of kilometers, the relative measurement sensor has little influence on the field of view.
S3, simplifying the test model
In the ground test, the rotation of the aircraft around the center of mass is realized by operating the air bearing table or the rotary table, as shown in fig. 5. Theta in orbit flight1、θ3For variable-speed movement, the angular velocity is not constant, which brings certain difficulty to the operation of the air bearing table or the turntable. To further simplify the ground model, may be at θ1、θ3Selecting a plurality of characteristic points on the on-orbit variation curve, and fitting by using a segmented straight line. At this time, the air bearing table or the turntable only needs to rotate at a constant angular velocity in sections. Let the coordinates of two points on the curve be (x)1,y1)、(x2,y2) Then, the formula of the straight line passing through two points is:
y＝kx+b (1)
wherein x and y are variables, k is a slope, and b is an intercept of the straight line on the y axis. Are respectively determined by the following formula:
k＝(y2-y1)/(x2-x1) (2)
b＝y1-kx1(3)
k is the rotation angular velocity of the air bearing table or the rotary table. After selecting the feature points on the curve, a straight line between two adjacent points can be determined according to equations (1) to (3).
S4, carrying out sensor view field verification on the simplified test model
Whether the simplified model obtained in the step 3 can be used for ground tests needs to be verified through the view field of the intersection measuring sensor. Namely, whether the view field conditions of the target device and the tracker at respective sensors are consistent with those in orbit is judged, and the method comprises the following steps:
and establishing a test coordinate system by taking the centroid of the target device as an origin and the sight line vector r as an x axis. The degree of freedom of the target in the test coordinate system is then theta1Degree of freedom of the tracker is theta3And a relative distance r from the target along the x-axis. And determining the coordinates of the intersection measuring sensors matched between the target device and the tracker under respective body coordinate systems, and obtaining the coordinates of the intersection measuring sensors under a test coordinate system through coordinate conversion. Taking verification of the field of view of the end sensor of the target as an example, as shown in fig. 6:
when the target and the tracker are based on the on-orbit actual theta1、θ3And when r moves in the test coordinate system, obtaining a vector t of the target end sensor pointing to the tracker end sensor according to the coordinates of the two sensors, obtaining a direction vector s of the target end sensor according to the installation angle, solving an included angle between s and t, and when the included angle is smaller than the half cone angle of the maximum view field of the sensor0And when the tracker end sensor is in the field of view of the target end sensor, the tracker end sensor is considered to be in the field of view of the target end sensor.
S5, correcting the test model
When the view field condition of the simplified test model sensor is inconsistent with the on-orbit model, the simplified model needs to be adjusted, and the method specifically comprises the following two aspects: and (4) increasing the number of the characteristic points selected in the step (3) and further accurately fitting the on-orbit motion curve. If a simplified mode of fixing the relative distance r between the two aircrafts is adopted to obtain the simplified model, the value of r should be properly adjusted.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (5)
1. A spacecraft close-range rendezvous test simplification method comprises the following steps:
s1, determining a sight vector from the center of mass of the tracker to the center of mass of the target, a longitudinal axis of a body coordinate system of the tracker, a longitudinal axis of the body coordinate system of the target, an included angle between the longitudinal axis of the tracker and the sight vector, and an included angle between the longitudinal axis of the target and the sight vector to establish a relative motion relationship between the target and the tracker;
s2, constructing a ground test model, taking the ground as a track plane, adjusting a sight line vector from the mass center of the tracker to the mass center of the target, an included angle between the longitudinal axis of the tracker and the sight line vector and an included angle between the longitudinal axis of the target and the sight line vector to simulate the actual relative motion of the tracker and the target in orbit;
s3, selecting a plurality of characteristic points on an on-orbit change curve of an included angle between a longitudinal axis of the tracker and a sight line vector and an included angle between the target and the sight line vector, and fitting by using a segmented straight line to simplify the test model;
and step S4, carrying out sensor field verification on the simplified test model, obtaining a vector of the end sensor of the target device pointing to the end sensor of the tracker according to sensor coordinates of the target device and the tracker, obtaining a direction vector of the end sensor of the target device according to the installation angle, and if an included angle between the vector of the end sensor of the target device pointing to the end sensor of the tracker and the direction vector of the end sensor of the target device is smaller than the maximum field half-cone angle of the sensor, determining that the verification result is in a normal range.
2. A simplified method for close-range rendezvous test of spacecraft according to claim 1, wherein if the sensor field of view verification performed on the simplified test model in the step S4 is not within a normal range, the method further comprises the step S5: and correcting the test model.
3. The spacecraft close-up encounter test simplification method of claim 2, wherein in the step S3, the method for simplifying the test model further comprises a mode of fixing the relative distance between the target centroid and the tracker centroid.
4. A simplified method for spacecraft close-up encounter test according to claim 2, wherein in the step S5, the method returns to the step S3, increases the number of selected feature points, and repeats the steps S3 to S4 until the verification result is within the normal range.
5. A spacecraft close-up encounter test simplification method according to claim 3, characterized in that if the test model is simplified in the step S3 by fixing the relative distance between the target centroid and the tracker centroid, the relative distance between the target centroid and the tracker centroid is adjusted to modify the test model in the step S5.
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