阅读说明：本技术 一种基于绳系收放装置的拖曳离轨方法 (Towing and derailing method based on rope system retracting device ) 是由 刘禹 段佳佳 王焕杰 方圆 张召弟 张国柱 于 2019-09-25 设计创作，主要内容包括：本发明公开了一种基于绳系收放装置的拖曳离轨方法,在对目标星的整个拖拽过程中,利用任务星上的绳系收放装置输出恒定的小张力,保持连接于任务星和目标星之间的系绳张紧；具体包括以下步骤：步骤1：建立任务星和目标星各自的质心动力学方程和姿态动力学方程,以及系绳的动力学模型；步骤2：以拖曳方向为目标进行组合体姿态机动；步骤3：任务星通过系绳拖曳目标星离轨,期间控制组合体姿态,使其朝向拖曳方向。本发明基于绳系收放装置的拖曳离轨方法,利用绳系收放装置产生恒小张力,既保证系绳张紧无缠绕风险,也保证系绳张力不会过大无断裂风险,将抓捕目标稳定安全地拖曳至坟墓轨道。(The invention discloses a towing derailing method based on a rope system retracting device, which is characterized in that in the whole towing process of a target satellite, a rope system retracting device on a task satellite is used for outputting constant small tension to keep a tether connected between the task satellite and the target satellite to be tensioned; the method specifically comprises the following steps: step 1: establishing a mass center kinetic equation and an attitude kinetic equation of the task star and the target star respectively, and a tether kinetic model; step 2: performing attitude maneuver of the assembly by taking the dragging direction as a target; and step 3: the mission star drags the target star off-orbit through the tether, and the attitude of the combination body is controlled to be towards the dragging direction. The towing and derailing method based on the rope system retracting device utilizes the rope system retracting device to generate constant and small tension, ensures that the rope system is tensioned without winding risk and also ensures that the rope system is not too large without breaking risk, and stably and safely tows the target to be caught to the tomb track.)

1. A towing and derailing method based on a rope system retracting device is characterized in that in the whole towing process of a target star, a rope system retracting device on a task star is used for outputting constant small tension to keep a tether connected between the task star and the target star tensioned; the method specifically comprises the following steps:

step 1: establishing a mass center kinetic equation and an attitude kinetic equation of the task star and the target star respectively, and a tether kinetic model;

step 2: performing attitude maneuver of the assembly by taking the dragging direction as a target;

and step 3: the mission star drags the target star off-orbit through the tether, and the attitude of the combination body is controlled to be towards the dragging direction.

2. The towing derailment method based on the rope system retracting device according to claim 1, wherein in the step 1, the respective centroid kinetic equations of the mission star and the target star under the geocentric inertial system are as follows:

wherein μ is the gravitational constant of the earth, r_mIs a vector of the center of mass of the task star in the inertial system, r_tIs the vector of the target star centroid in the inertial system, M_mFor task star quality, M_tIs the target star mass, F_thFor orbital thrust exerted on mission satellites, F_TIs the tether tension.

3. The towing derailment method based on the rope system retracting device according to claim 1, wherein in the step 1, the respective attitude kinetic equations of the task star and the target star are as follows:

wherein, I_mIs a rotational inertia matrix of the mission star, I_tIs the rotational inertia matrix, omega, of the target star_mFor the projection of the angular velocity of the mission star under the mission star system, omega_tFor the projection of the target star angular velocity in the target star system, C_mbiAttitude transfer matrix for geocentric inertial system to mission satellite body system, C_tbiAttitude transfer matrix, T, for the Earth's Heart inertial System to the target Star's body System_cControlling the moment for the attitude of the task star, F_TFor tether tension, p_mFor the towing and hanging point vector, p, of the mission star system rope under the mission star system_tThe target star tether towing point vector under the target star system is obtained.

4. The towing derailment method based on the rope system retracting device according to claim 1, wherein in the step 1, in the dynamic model of the rope system, a connecting line vector of a mission star system rope towing point and a target star system rope towing point is defined as L_tmAnd the direction is from the target star tying rope pulling and hanging point to the task star tying rope pulling and hanging point, then:

wherein, C_mbiAttitude transfer matrix for geocentric inertial system to mission satellite body system, C_tbiAttitude transfer matrix, p, for the Earth's Heart inertial System to the target Star's System_mFor the towing and hanging point vector, p, of the mission star system rope under the mission star system_tA target star tether towing point vector r of a target star system_mIs a vector of the center of mass of the task star in the inertial system, r_tThe vector of the target star centroid in the inertial system is shown; then there are:

wherein, F_TFor tether tension, L is the original length of the tether when it is relaxed, and tether lengthAmount of deformation Δ L ═ L_tmL, D is the tether diameter, E is the tether modulus of elasticity, and η is the tether damping coefficient.

5. The towing derailment method based on the rope system retracting device according to claim 1, wherein in the step 2, the relative position direction of two stars at the time of maneuvering is r₁And the direction r of the final relative position of the two stars₀＝[1 0 0]Determining a plane in which the air injection direction of the mission star and the relative position direction of the two stars at the maneuvering time are perpendicular, and the normal n ═ r of the plane₁×r₀Setting the air jet direction of the mission star as dir, then there is dir ⊥ r₁And dir ⊥ n, wherein the jet direction of the mission star in the attitude maneuver process of the assembly is calculated by the following formula₁X is x n; after the attitude maneuver is completed, the relative speed of the two stars arranged under the target star orbit system is V, and the air injection direction xc _ dir of the mission star after the attitude maneuver is completed is as follows:

wherein, the | V | is a module value of relative speed of two stars.

6. The towing derailment method based on the rope system retracting device according to claim 5, wherein in the step 3, when the distance between two stars is smaller than the safety distance, the mission star jets are far away; and when the distance between the two stars reaches a distance threshold value, the mission star stops air injection.

Technical Field

The invention relates to a rope system combination body dragging and derailing control technology, in particular to a dragging and derailing method based on a rope system retracting device.

Background

Geostationary Earth Orbit (GEO) has a wide application value due to the particularity of being stationary relative to the ground, is a very important scarce resource, and has a great importance in the space strategy of each aerospace country. With the increasing demand of various countries in the fields of communication, broadcasting, weather, navigation and the like, more and more aircrafts enter the limited space, and the demand of removing the GEO-orbit garbage is urgent.

The safety of the on-orbit operation spacecraft is seriously threatened by the existence of the space debris, and the collision between the space debris and the spacecraft can change the performance of the spacecraft, cause damage to surface devices, cause system failure of the spacecraft and influence the service life of the spacecraft. The target is captured through the fly net and is dragged to the grave track, the track garbage cleaning device is a novel scheme for cleaning track garbage, and due to the characteristics of strong adaptability, reusability and the like, the track garbage cleaning device is widely concerned and researched.

After the rope net captures the target, the control aircraft and the target aircraft form a flexible combination body which takes the rope as a connecting medium, the motion of the combination body in space relates to the orbital motion of the mass center of the combination body, the relative motion of the two bodies of the control aircraft and the target aircraft and the coupling dynamics between the two bodies, and how to efficiently and safely remove the flexible combination body becomes a research focus. Because the tether has the characteristics of small damping and high flexibility, the dynamics and control problems of the tether are very complex, and a series of complex swinging and vibration are very easy to generate when the tether is placed in a space environment and coupled with a spacecraft. When the drag removal control scheme is designed, on the basis of considering safety factors, the feasibility in practical engineering application is ensured and related control performance indexes are met.

Disclosure of Invention

The invention aims to provide a dragging and derailing method based on a rope system retracting device, which can generate constant and small tension through the rope system retracting device and stably and safely drag a catching target to a grave track.

In order to achieve the aim, the invention provides a towing and derailing method based on a rope system retracting device, wherein in the whole towing process of a target star, the rope system retracting device on the task star outputs constant small tension to keep the tension of a tether connected between the task star and the target star; the method specifically comprises the following steps:

step 1: establishing a mass center kinetic equation and an attitude kinetic equation of the task star and the target star respectively, and a tether kinetic model;

step 2: performing attitude maneuver of the assembly by taking the dragging direction as a target;

and step 3: the mission star drags the target star off-orbit through the tether, and the attitude of the combination body is controlled to be towards the dragging direction.

In the towing and derailing method based on the rope system retracting device, in step 1, the respective centroid kinetic equations of the mission star and the target star under the geocentric inertial system are as follows:

wherein μ is the gravitational constant of the earth, r_mIs a vector of the center of mass of the task star in the inertial system, r_tIs the vector of the target star centroid in the inertial system, M_mFor task star quality, M_tIs the target star mass, F_thFor orbital thrust exerted on mission satellites, F_TIs the tether tension.

In the towing and derailing method based on the rope system retracting device, in step 1, the attitude kinetic equations of the task star and the target star are as follows:

wherein, I_mIs a rotational inertia matrix of the mission star, I_tIs the rotational inertia matrix, omega, of the target star_mFor the projection of the angular velocity of the mission star under the mission star system, omega_tFor the projection of the target star angular velocity in the target star system, C_mbiAttitude transfer matrix for geocentric inertial system to mission satellite body system, C_tbiAttitude transfer matrix, T, for the Earth's Heart inertial System to the target Star's body System_cControlling the moment for the attitude of the task star, F_TFor tether tension, p_mFor the towing and hanging point vector, p, of the mission star system rope under the mission star system_tThe target star tether towing point vector under the target star system is obtained.

In the towing and derailing method based on the rope system retracting device, in step 1, in the dynamic model of the tether, a connecting line vector of a task star system rope towing and hanging point and a target star system rope towing and hanging point is defined as L_tmAnd the direction is from the target star tying rope pulling and hanging point to the task star tying rope pulling and hanging point, then:

wherein, C_mbiAttitude transfer matrix for geocentric inertial system to mission satellite body system, C_tbiAttitude transfer matrix, p, for the Earth's Heart inertial System to the target Star's System_mFor the towing and hanging point vector, p, of the mission star system rope under the mission star system_tA target star tether towing point vector r of a target star system_mIs a vector of the center of mass of the task star in the inertial system, r_tThe vector of the target star centroid in the inertial system is shown; then there are:

wherein, F_TFor tether tension, L is the original length of the tether when it is relaxed, and the tether length deformation quantity DeltaL ═ L_tmL, D is the tether diameter, E is the tether elastic modulus, η is the tether damping coefficient, and the tether tensioning direction is the tether tension direction.

In the above towing derailing method based on the rope system retracting device, in step 2, the relative position direction of the two stars at the maneuvering time is r₁And the direction r of the final relative position of the two stars₀＝[1 0 0]Determining a plane in which the air injection direction of the mission star and the relative position direction of the two stars at the maneuvering time are perpendicular, and the normal n ═ r of the plane₁×r₀Setting the air jet direction of the mission star as dir, then there is dir ⊥ r₁And dir ⊥ n, wherein the jet direction of the mission star in the attitude maneuver process of the assembly is calculated by the following formula₁X is x n; after the attitude maneuver is completed, setting the relative speed of the two stars as V, and then the air injection direction xc _ dir of the task star after the attitude maneuver is completed is as follows:

wherein, the | V | is a module value of relative speed of two stars.

In the towing and derailing method based on the rope system retracting device, in the step 3, when the distance between two stars is smaller than the safety distance, the air jet of the task star is far away; and when the distance between the two stars reaches a distance threshold value, the mission star stops air injection.

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

the towing and derailing method based on the rope system retracting device can be applied to towing and removing tasks after a space flying net catches a target. For the space control unstable target, after the target is captured by the fly net, the tension of the tether can be controlled through the tether retracting device, and the target is stably dragged by controlling the tether tension. The tether is ensured not to be loosened when the tether tension exists, and the risk that the tether is wound around the target star is avoided; the small tension output by the rope system retracting device ensures that the rope system is not broken. The capability of the rope winding and unwinding device for generating tension is utilized to keep the rope to output constant small tension, and the target track is gradually lifted by pulling the target through the small tension. The invention designs a series of control schemes from the attitude steering of the combination body to the stable dragging off-rail and the stable attitude of the combination body during the dragging off-rail by effectively utilizing the rope system retracting device.

Drawings

FIG. 1 is a schematic drawing of a trailing derailment based tether take-up and pay-off;

FIG. 2 is a schematic view of the direction of the jet of the attitude maneuver of the tethered combination;

FIG. 3 is a schematic diagram of the rope combination towing derailing method.

Detailed Description

The invention will be further described by the following specific examples in conjunction with the drawings, which are provided for illustration only and are not intended to limit the scope of the invention.

As shown in fig. 1, the invention provides a towing derailing method based on a rope system retracting device 3, wherein in the whole towing process of a target star 1, a rope system retracting device 3 on a task star 2 is used for outputting constant small tension to keep a tether 4 connected between the task star 2 and the target star 1 tensioned; the method specifically comprises the following steps:

step 1: and establishing a mass center kinetic equation and an attitude kinetic equation of each of the task star 2 and the target star 1 and a kinetic model of the tether 4.

(1) The respective mass center kinetic equations of the task star 2 and the target star 1 under the geocentric inertial system are as follows:

wherein μ is the gravitational constant of the earth, r_mIs the vector of the center of mass of task star 2 in the inertial system, r_tIs the vector of the target star 1 centroid in the inertial system, M_mTask Star 2 quality, M_tIs the target star 1 mass, F_thFor orbital thrust exerted on task Star 2, F_TIs the tether 4 tension.

(2) Ignoring the flexibility of the task star 2 and the target star 1, and regarding the flexibility as a rigid body, the respective attitude kinetic equations of the task star 2 and the target star 1 can be established by adopting the momentum moment law as follows:

wherein, I_mIs a rotational inertia matrix of task Star 2, I_tIs the rotational inertia matrix, omega, of the target satellite 1_mIs the projection of the angular velocity of the mission star 2 under the mission star 2 system, omega_tIs a projection of the angular velocity of the target satellite 1 under the system of the target satellite 1, C_mbiAttitude transfer matrix for the geocentric inertial system to the satellite 2 body system, C_tbiAttitude transfer matrix, T, for the Earth's Heart inertial System to the target Star 1 body System_cControlling the moment for the attitude of task Star 2, F_TTo tether 4 tension, p_mA task star 2 tether 4 suspension point vector, p, for a task star 2 body system_tThe tie point vector of the tether 4 of the target star 1 under the tether of the target star 1 is shown.

(3) An elastic rod model without compression resistance is adopted in modeling, the mass of the tether 4 is not counted, only the longitudinal elastic deformation of the tether 4 is considered, the tether 4 cannot resist compression, and only tensile stress exists. The tether 4 tension is related only to the tether 4 length deformation amount Δ L. A connecting line vector of a towing point of a tether 4 of the task star 2 and a towing point of a tether 4 of the target star 1 is defined as L_tmAnd the direction is from the traction point of the target star 1 tether 4 to the traction point of the task star 2 tether 4, then:

wherein, C_mbiAttitude transfer matrix for the geocentric inertial system to the satellite 2 body system, C_tbiAttitude transfer matrix, p, for the Earth's Heart inertial System to the target Star 1 body System_mA task star 2 tether 4 suspension point vector, p, for a task star 2 body system_tIs a target star 1 tether 4 suspension point vector r under a target star 1 body system_mIs the vector of the center of mass of task star 2 in the inertial system, r_tThe vector of the centroid of the target star 1 in the inertial system; then there are:

wherein, F_TThe tension of the tether 4, L is the original length of the tether 4 when it is relaxed, and the deformation amount Δ L ═ L of the length of the tether 4_tmL, D is the diameter of the tether 4, E is the elastic modulus of the tether 4, η is the damping coefficient of the tether 4, and the tensioning direction of the tether 4 is the tensioning direction of the tether 4.

Step 2: and (4) carrying out assembly attitude maneuver by taking the dragging direction, namely the x-axis direction of the orbit as a target.

As shown in fig. 2, it is assumed that the relative position direction of the two satellites (i.e. the normalized vector of the position vector of the mission satellite under the target satellite orbit system) at the maneuvering time is r₁Then from the two stars final relative position direction r₀＝[1 0 0]A plane can be determined in which the jet direction of the mission star 2 and the relative position direction of the two stars at the time of maneuvering are perpendicular, and the normal n ═ r of the plane is determined₁×r₀(ii) a The air injection direction of the mission star 2 is set to dir ═ x yz]Then there is dir ⊥ r₁And dir ⊥ n, wherein the air injection direction of the task star 2 in the process of the attitude maneuver of the assembly is calculated by the following formula:

dir＝r₁×n；

when the air injection direction is calculated by the formula, in order to ensure that the mission star 2 moves backwards and approaches to the x axis of the orbit, x is taken to be more than 0.

After the attitude maneuver is completed, the speed in the non-orbital x-axis direction is eliminated, the relative speed of the two stars is set to be V, and the air injection direction xc _ dir of the task star after the attitude maneuver is completed is as follows:

wherein, the | V | is a module value of relative speed of two stars.

And during the attitude maneuver of the combination body, the rope winding and unwinding device 3 is utilized to generate constant small tension and keep the rope 4 tensioned.

And step 3: the mission star 2 drags the target star 1 off-orbit through the tether 4, and controls the attitude of the combination body to be oriented in the dragging direction, namely the x-axis direction of the orbit.

The method comprises the following steps of rope combination attitude stabilization and rope combination body dragging off-track strategy design:

and the attitude of the assembly is stable, namely the attitude of the assembly with small amplitude is maneuvering, the maneuvering direction is the dir direction, after the attitude of the assembly is in place, the speed in the non-orbital x-axis direction is eliminated, and the air injection direction of the mission star 2 is the xc _ dir direction.

The rope system assembly dragging off-rail strategy is to control the rope system winding and unwinding device 3 to generate constant small tension, the distance between the two stars is reduced along with the tension, when the distance between the two stars is smaller than the safety distance, the mission star 2 jets air to be far away, when the distance between the two stars reaches a far-away threshold value, the mission star 2 stops jetting air, and the assembly dragging off-rail process is as shown in fig. 3.

In conclusion, the towing and derailing method based on the rope system retracting device utilizes the rope system retracting device to generate constant and small tension, and not only ensures that the rope system is tensioned without winding risk, but also ensures that the rope system is not too large in tension without breaking risk.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.