CN112793809A - Bidirectional LOS vector-based inter-satellite relative attitude control method - Google Patents

Abstract

The invention discloses a relative attitude control method based on a bidirectional LOS vector, which comprises the following steps: measuring a bidirectional LOS vector between a master spacecraft and a slave spacecraft by using an array antenna; measuring a bidirectional LOS vector between a serving spacecraft and a slave spacecraft using an array antenna; calculating a LOS vector error equation between the master spacecraft and the slave spacecraft and a LOS vector error equation between the service spacecraft and the slave spacecraft; the error equations are represented by two sets of LOS vectors and the expected relative attitude, and the control inputs are designed accordingly. The method considers the fast changing dynamic topological structure of the satellite formation, the control input only contains the LOS vector information, the relative attitude between the satellites can be controlled without solving the absolute attitude of the satellite, the control response time is saved, and the control structure is simple.

Description

Bidirectional LOS vector-based inter-satellite relative attitude control method

Technical Field

The invention belongs to the field of relative attitude control, and particularly relates to an inter-satellite relative attitude control method based on a bidirectional LOS vector.

Background

With the miniaturization trend of the satellites, the satellites can be formed into formation to complete various complex tasks, such as detecting the atmosphere, detecting the environment, forming a synthetic aperture radar, and the like. Accurate relative pose information in the formation is the basis on which these tasks can be successfully accomplished.

Because the topology change of the satellite formation is fast, the real-time requirement on the relative attitude control is very high, the controller needs to respond to the requirement of the relative attitude fast, and the traditional relative attitude controller needs to calculate the absolute attitude of the satellite first, so most time is consumed, and the requirement of the relative controller on response fast cannot be met.

Disclosure of Invention

In order to solve the problem that the requirement of quick response of a relative controller cannot be met in the prior art, the invention provides a method for controlling the relative attitude between satellites based on a bidirectional LOS vector.

The invention adopts the following technical scheme:

a control method for relative attitude between satellites based on bidirectional LOS vectors utilizes the bidirectional LOS vectors as control input to control the relative attitude and realize the attitude synchronization of two satellites, and specifically comprises the following steps:

s1, carrying array antennas on all satellites in the formation;

s2, measuring a bidirectional LOS vector between the master spacecraft and the slave spacecraft by using the array antenna;

s3, measuring a bidirectional LOS vector between the serving spacecraft and the slave spacecraft by using the array antenna;

s4, calculating a LOS vector error equation between the master spacecraft and the slave spacecraft and a LOS vector error equation between the service spacecraft and the slave spacecraft;

and S5, representing the error equation by two sets of LOS vectors and expected relative postures, and further designing control input.

As a further improvement of the present invention, the formation in step S1 includes a master space vehicle, a serving space vehicle, K slave space vehicles and K +2 space vehicles, wherein the array antennas carried by the master space vehicle and the serving space vehicle are used as receivers to receive signals transmitted by the array antennas of the slave space vehicles.

As a further improvement of the present invention, in step S2, a suitable LOS vector calculation method is selected to obtain LOS vectors u from the master spacecraft to the slave spacecraft_1,kLOS vector v from spacecraft to host spacecraft_k,1And k represents a vector related to the kth slave spacecraft, and the LOS vector is obtained by utilizing the arrival angle of the receiving array antenna and the departure angle of the transmitting array antenna of the array signal processing algorithm.

As a further improvement of the present invention, in step S3, a suitable LOS vector calculation method is selected to obtain an LOS vector u from the serving spacecraft to the slave spacecraft_2,kLOS vector v from spacecraft to space service_k,2K denotes a vector associated with the kth slave spacecraft; and the LOS vector is further solved by utilizing the arrival angle of the wave to the receiving array antenna and the departure angle of the wave to the transmitting array antenna of the array signal processing algorithm.

As a further improvement of the present invention, in the step S4, a relative attitude constraint equation is constructed according to the two-way LOS vector in the steps S2 and S3, namely

In the formula z₁And u_1,kLOS vector from master spacecraft to slave spacecraft, where v_k,1LOS vector from spacecraft to main spacecraft, z₂And u_2,kLOS vector, v, for serving spacecraft to slave spacecraft_k,2LOS vector from spacecraft to space service, L_k,1To serve the relative attitude of the spacecraft with respect to the main spacecraft, the upwelling lines represent the measurements.

Obtaining the difference between the relative attitude and the expected attitude by using a relative attitude constraint equation and obtaining a relative attitude error; namely, it is

And

in the formula z₁LOS vector from master spacecraft to slave spacecraft, where v_k,1LOS vector from spacecraft to main spacecraft, z₂LOS vector, v, for serving spacecraft to slave spacecraft_k,2LOS vector from spacecraft to space service, L_d,kFor the desired relative pose, superscript T represents the transpose of the matrix, η₁、η₂And η_kRepresenting a three-dimensional infinitesimal quantity;

as a further improvement of the present invention, in step S5, the expressions of the control inputs of the master spacecraft and the slave spacecraft are respectively:

u₁＝-k_o1Ω₁-k₁ψ_1，1-k₂ψ_2，1

and

u₂＝-k_o2Ω₂-k₁ψ_1，2-k₂ψ_2，2

in the formula, omega₁Angular velocity, omega, of the primary spacecraft₂For angular velocity of the slave spacecraft, k_o1、k_o2、k₁And k₂Is four constants.

Compared with the prior art, the invention has at least the following beneficial effects:

the method considers the fast changing dynamic topological structure of the satellite formation, the control input only contains the LOS vector information, the relative attitude between the satellites can be controlled without solving the absolute attitude of the satellite, the control response time is saved, and the control structure is simple. The method has the advantages of simple design, low operation complexity, good real-time performance and wide application range.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art 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 for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic diagram of a satellite formation according to the present invention;

FIG. 2 is a schematic view of an inter-satellite bidirectional LOS vector of the present invention;

fig. 3 shows the geometry of the master, serving and one slave spacecraft, showing the LOS vectors and the angles between the vectors between the three spacecraft.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to solve the technical problem of providing a method for controlling the relative attitude of a micro-nano satellite, which has the advantages of simple design, low operation complexity, good real-time performance and wide application range, aiming at the defects in the prior art.

The invention adopts the following technical scheme:

the relative attitude control method based on the bidirectional LOS vector mainly utilizes the bidirectional LOS vector as control input to control the relative attitude and realize the attitude synchronization of two satellites, and comprises the following steps:

and S1, carrying array antennas on all the satellites in the formation.

The formation in step S1 includes a master spacecraft, a service spacecraft, and K slave spacecraft, and is formed by K +2 spacecraft, where array antennas carried by the master spacecraft and the service spacecraft serve as receivers to receive signals transmitted from the array antennas of the slave spacecraft.

And S2, measuring a bidirectional LOS vector between the master spacecraft and the slave spacecraft by using the array antenna.

Step S2, selecting a proper LOS vector calculation method to obtain an LOS vector u from the main spacecraft to the slave spacecraft_1,kLOS vector v from spacecraft to host spacecraft_k,1And k denotes a vector associated with the kth slave spacecraft. The present invention refers to these two LOS vectors as bidirectional LOS vectors.

And S3, measuring a bidirectional LOS vector between the serving spacecraft and the slave spacecraft by using the array antenna.

Step S3, selecting a proper LOS vector calculation method to obtain an LOS vector u from the service spacecraft to the slave spacecraft_2,kLOS vector v from spacecraft to space service_k,2And k denotes a vector associated with the kth slave spacecraft. The present invention refers to these two LOS vectors as bidirectional LOS vectors.

S4, calculating a LOS vector error equation between the master spacecraft and the slave spacecraft and a LOS vector error equation between the service spacecraft and the slave spacecraft.

In the step S4, a relative attitude constraint equation is constructed according to the two-way LOS vector in the step S2 and the step S3, namely

And obtaining the difference sum of the relative attitude and the expected attitude by using a relative attitude constraint equation to be a relative attitude error.

Namely, it is

And

in the formula L_d,kFor the desired relative pose, superscript T represents the transpose of the matrix, η₁、η₂And η_kRepresenting an infinitesimal quantity in three dimensions.

And S5, representing the error equation by two sets of LOS vectors and expected relative postures, and further designing control input.

In step S5, the expressions of the control inputs of the master spacecraft and the slave spacecraft are respectively:

u₁＝-k_o1Ω₁-k₁ψ_1，1-k₂ψ_2，1

and

u₂＝-k_o2Ω₂-k₁ψ_1，2-k₂ψ_2，2

in the formula, omega₁Angular velocity, omega, of the primary spacecraft₂For angular velocity of the slave spacecraft, k_o1、k_o2、k₁And k₂Is four constants.

The invention is described in detail below with reference to the figures and the specific embodiments.

Examples

The invention relates to a bidirectional LOS vector-based inter-planet relative attitude control method, which comprises the following five steps:

s1, measuring a bidirectional LOS vector between the master spacecraft and the slave spacecraft by using the array antenna;

s2, measuring a bidirectional LOS vector between the serving spacecraft and the slave spacecraft by using the array antenna;

s3, calculating a LOS vector error equation between the master spacecraft and the slave spacecraft and a LOS vector error equation between the service spacecraft and the slave spacecraft;

s4, the error equation is expressed by two sets of LOS vectors and expected relative postures, and control input is designed.

The specific steps are described as follows:

s1 measuring a bidirectional LOS vector between a master spacecraft and a slave spacecraft using an array antenna

Referring to FIG. 1, CV is shown₁Representing the main spacecraft, DV_kThe method comprises the steps that array antennas are installed on the two spacecrafts, and the LOS vector is solved by utilizing the arrival angle of the receiving array antenna and the departure angle of the transmitting array antenna of an array signal processing algorithm.

S2 measuring a bidirectional LOS vector between a serving spacecraft and a slave spacecraft using an array antenna

Referring to FIG. 1, CV is shown₂Representing a service spacecraft, DV_kThe method comprises the steps that array antennas are installed on the two spacecrafts, and the LOS vector is solved by utilizing the arrival angle of the receiving array antenna and the departure angle of the transmitting array antenna of an array signal processing algorithm.

S3 calculating LOS vector error equation between the master spacecraft and the slave spacecraft and LOS vector error equation between the service spacecraft and the slave spacecraft

In this embodiment, it is assumed that the master spacecraft and the slave spacecraft have the same rotational inertia matrix, that is, the master spacecraft and the slave spacecraft have the same rotational inertia matrix

Spacecraft CV₁Service spacecraft CV₂And from spacecraft DV_kThe unit LOS vector in between is represented in the inertial coordinate system as:

s_k，2＝[0，0，-1]^T＝-s_2，k

another expected relative attitude is I_3*3Namely a three-dimensional identity matrix, namely that the relative attitude control task is the synchronization of the slave spacecraft and the master spacecraft attitude. The initial postures of the two spacecrafts are respectively

R₁(0)＝exp(π[s_k，1×])

R_k(0)＝exp(π[s_k，2×])

The initial values of the relative attitude error function are Δ 1(0) ═ 1.9995 and Δ 2(0) ═ 2. Master and slave spacecraft

Initial angular velocities of the device are Ω 1(0) ═ 0,0.5,0.3, respectively]^T(rad/s)，Ω2(0)＝[0.2,-0.1,0.6]^T(rad/s)

S4 represents the error equation with two sets of LOS vectors and the desired relative attitude to design the control inputs.

u₁＝-k_o1Ω₁-k₁ψ_1，1-k₂ψ_2，1

And

u₂＝-k_o2Ω₂-k₁ψ_1，2-k₂ψ_2，2

in this embodiment, the control input parameter is k_o1＝k_o2＝0.74，k₁＝0.4250，k₁＝0.4755。

The invention is not described in detail and is part of the common general knowledge of a person skilled in the art.

All articles and references disclosed above, including patent applications and publications, are hereby incorporated by reference for all purposes. The term "consisting essentially of …" describing a combination shall include the identified element, ingredient, component or step as well as other elements, ingredients, components or steps that do not materially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, components, or steps herein also contemplates embodiments that consist essentially of such elements, components, or steps. By using the term "may" herein, it is intended to indicate that any of the described attributes that "may" include are optional.

A plurality of elements, components, parts or steps can be provided by a single integrated element, component, part or step. Alternatively, a single integrated element, component, part or step may be divided into separate plural elements, components, parts or steps. The disclosure of "a" or "an" to describe an element, ingredient, component or step is not intended to foreclose other elements, ingredients, components or steps.

It is to be understood that the above description is intended to be illustrative, and not restrictive. Many embodiments and many applications other than the ones provided will be apparent to those of skill in the art upon reading the above description. The scope of the present teachings should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are hereby incorporated by reference for all purposes. The omission in the foregoing claims of any aspect of subject matter that is disclosed herein is not intended to forego such subject matter, nor should the applicant consider that such subject matter is not considered part of the disclosed subject matter.

Claims (6)

1. A method for controlling relative attitude between satellites based on a bidirectional LOS vector is characterized in that the bidirectional LOS vector is used as control input to control the relative attitude, so that the attitude synchronization of two satellites is realized, and the method specifically comprises the following steps:

s1, carrying array antennas on all satellites in the formation;

s2, measuring a bidirectional LOS vector between the master spacecraft and the slave spacecraft by using the array antenna;

s3, measuring a bidirectional LOS vector between the serving spacecraft and the slave spacecraft by using the array antenna;

s4, calculating a LOS vector error equation between the master spacecraft and the slave spacecraft and a LOS vector error equation between the service spacecraft and the slave spacecraft;

and S5, representing the error equation by two sets of LOS vectors and expected relative postures, and further designing control input.

2. The method of claim 1, wherein the formation in step S1 includes a master space vehicle, a service space vehicle, K slave space vehicles, and K +2 space vehicles, wherein the array antennas carried by the master space vehicle and the service space vehicle are used as receivers for receiving signals transmitted from the array antennas of the slave space vehicles.

3. The method of claim 1, wherein in step S2, the LOS vector u from the master spacecraft to the slave spacecraft is obtained by selecting a suitable LOS vector calculation method_1,kLOS vector v from spacecraft to host spacecraft_k,1And k represents a vector related to the kth slave spacecraft, and the LOS vector is obtained by utilizing the arrival angle of the receiving array antenna and the departure angle of the transmitting array antenna of the array signal processing algorithm.

4. The method of claim 1, wherein the step S3 is performed by selecting a suitable LOS vector calculation method to obtain LOS vector u from the serving spacecraft to the slave spacecraft_2,kLOS vector v from spacecraft to space service_k,2K denotes a vector associated with the kth slave spacecraft; and the LOS vector is further solved by utilizing the arrival angle of the wave to the receiving array antenna and the departure angle of the wave to the transmitting array antenna of the array signal processing algorithm.

5. The method of claim 1, wherein in step S4, a relative attitude constraint equation is constructed from the two-way LOS vector in steps S2 and S3

In the formula z₁And u_1,kLOS vector from master spacecraft to slave spacecraft, where v_k,1LOS vector from spacecraft to main spacecraft, z₂And u_2,kLOS vector, v, for serving spacecraft to slave spacecraft_k,2LOS vector from spacecraft to space service, L_k,1For the relative attitude of the service spacecraft with respect to the main spacecraft, the upgoing wavy line represents the measurement quantity;

obtaining the difference between the relative attitude and the expected attitude by using a relative attitude constraint equation and obtaining a relative attitude error; namely, it is

And

in the formula z₁LOS vector from master spacecraft to slave spacecraft, where v_k,1LOS vector from spacecraft to main spacecraft, z₂LOS vector, v, for serving spacecraft to slave spacecraft_k,2LOS vector from spacecraft to space service, L_d,kFor the desired relative pose, superscript T represents the transpose of the matrix, η₁、η₂And η_kRepresenting an infinitesimal quantity in three dimensions.

6. The method of claim 1, wherein in step S5, the expressions of the control inputs of the master spacecraft and the slave spacecraft are respectively:

u₁＝-k_o1Ω₁-k₁ψ_1，1-k₂ψ_2，1

and

u₂＝-k_o2Ω₂-k₁ψ_1，2-k₂ψ_2，2

in the formula, omega₁Angular velocity, omega, of the primary spacecraft₂For angular velocity of the slave spacecraft, k_o1、k_o2、k₁And k₂Is four constants.

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