Spacecraft tumbling object tether despinning method and system with three-satellite cooperation

Abstract

The application relates to a three-satellite cooperative anti-tumbling tethered method and system for a space tumbling object, which comprises the following steps: establishing a three-satellite cooperative anti-tumbling space configuration; the configuration is composed of three service satellites with a motor ability, a first service satellite and a second service satellite are symmetrically distributed relative to the center of mass of the tumbling object, the distance from the first and second service satellites to the center of mass of the tumbling object is equal, and a third service satellite is distributed in the spin plane passing through the center of mass of the tumbling object; according to an anti-tumbling strategy of first eliminating the nutation angle and then eliminating the spin angular velocity, the anti-tumbling and tethering off-orbit tasks of the tumbling object are completed under the premise of ensuring the attitude stability of the tumbling object. Compared with other existing contact anti-tumbling schemes, the risk of accidental collision is reduced; the anti-tumbling strategy in the method solves the problem that the anti-tumbling effect of the tumbling object is limited by the tether and the rope net; compared with non-contact anti-tumbling, the tether can provide a large pulling force, reduce the anti-tumbling time, and can be used for subsequent tethering operations.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aerospace technology, in particular to a three-satellite cooperative tethered de-spinning and dragging method for a space tumbling object. BACKGROUND

[0002] A failed satellite in space not only occupies valuable orbital resources, but also poses a threat to normally operating satellites in orbit. Since the failed satellite is usually in a tumbling motion state, it becomes a space tumbling object, which may cause unexpected collision risks during the cleaning process. Therefore, the tumbling object needs to be de-spun first. At present, according to whether the service satellite has direct contact with the tumbling object, the de-spinning scheme can be divided into two categories: contact type and non-contact type. The contact type de-spinning scheme mainly includes: (1) mechanical pulse type: the mechanical arm or flexible brush on the service satellite contacts the tumbling object to generate a pulse type force, which can provide a large de-spinning torque. The disadvantage is that accidental collisions are easy to occur; (2) net de-spinning: the tumbling object is de-spun by tether and flexible net, which can avoid the risk of accidental collision. However, due to the use of flexible actuators, the de-spinning effect on the tumbling object is limited; (3) adhesion type de-spinning: a cube satellite with a propulsion system is adhered to the surface of the tumbling object, and the propulsion system is used to de-spin. This scheme has high requirements for the adhesion position and timing of the cube satellite. The non-contact type de-spinning scheme mainly includes: (1) electromagnetic de-spinning: the service satellite generates a magnetic field through a coil, and uses the Lenz theorem to generate an electromagnetic force on the tumbling object, thereby achieving the effect of de-spinning; (2) electrostatic force de-spinning: the service satellite sprays electrons on the tumbling object to make it overall charged, while the service satellite also emits electrons or positive ions to make itself charged, thereby generating a Coulomb force between the service satellite and the tumbling object to achieve the effect of de-spinning.

[0003] In summary, the mechanical pulse type de-spinning can provide a large de-spinning torque to achieve rapid de-spinning, but it has a high risk of accidental collision. The net de-spinning can avoid accidental collision, but the de-spinning effect on the tumbling object is limited. The non-contact type de-spinning scheme provides a small de-spinning torque, takes a long time, and cannot perform subsequent dragging operations. Therefore, it is necessary to propose a scheme that can quickly de-spin the tumbling object with a small collision risk and can perform subsequent dragging operations. SUMMARY

[0004] Therefore, it is necessary to provide a three-satellite cooperative tethered de-spinning and dragging method for a space tumbling object to solve the above technical problems. The method can quickly de-spin the tumbling object and is less likely to cause accidental collisions, and can drag the de-spun tumbling object out of orbit.

[0005] A three-satellite cooperative tethered de-spinning and dragging method for a space tumbling object, the method comprising:

[0006] A three-satellite cooperative despinning space configuration is established; the three-satellite cooperative despinning space configuration is composed of three service satellites with maneuvering capability, the first service satellite and the second service satellite are symmetrically distributed relative to the center of mass of the tumbling object, the distance from the first service satellite and the second service satellite to the center of mass of the tumbling object is equal, and the third service satellite is distributed in the spin plane passing through the center of mass of the tumbling object.

[0007] The first service satellite and the second service satellite use the tether ejection system to launch a flying spear to connect the tether to the upper and lower surfaces of the tumbling object, and the direction and size of the upward tension of the tether of the first service satellite and the second service satellite are controlled to eliminate the nutation angle.

[0008] After the nutation angle is eliminated, the third service satellite uses the tether ejection system to launch a flying spear to connect the tether to the side of the tumbling object, the direction and size of the upward tension of the tether of the third service satellite are controlled to eliminate the spin angular velocity, and then the tumbling object is deorbited.

[0009] In one embodiment, the first service satellite and the second service satellite use the tether ejection system to launch a flying spear to connect the tether to the upper and lower surfaces of the tumbling object, and the direction and size of the upward tension of the tether of the first service satellite and the second service satellite are controlled to eliminate the nutation angle, comprising:

[0010] The first service satellite and the second service satellite respectively launch a flying spear to connect the tether to two points O1 and O2 on the upper and lower surfaces of the tumbling object; wherein the point O1 and the point O2 are respectively the spin axis OZ B The intersection of the positive and negative half-axes and the upper and lower surfaces of the tumbling object.

[0011] The direction of the upward tension of the tether of the first service satellite and the second service satellite is controlled by a guidance law, and the size of the upward tension of the tether of the first service satellite and the second service satellite is controlled by a tether tension control law to eliminate the nutation angle.

[0012] In one embodiment, the direction of the upward tension of the tether of the first service satellite and the second service satellite is controlled by a guidance law, and the size of the upward tension of the tether of the first service satellite and the second service satellite is controlled by a tether tension control law to eliminate the nutation angle; comprising:

[0013] The angle between the line-of-sight direction between the first service satellite and the center of mass of the tumbling object and the direction of the angular momentum vector H of the tumbling object, the distance from the first service satellite to the center of mass of the tumbling object, and the distance from the second service satellite to the center of mass of the tumbling object are kept unchanged by the guidance law.

[0014] The electric wheels on the first service satellite and the second service satellite tighten the tether to exert a pulsed despinning tension on the tumbling object, and the size of the despinning tension is controlled by a tether tension control law to make the nutation angle decrease at a preset rate until it converges to zero.

[0015] In one embodiment, the despinning pull exerted on the tumbling object by the first and second service satellites satisfies the following conditions:

[0016] Establish an inertial coordinate system O-XYZ and a body coordinate system OX with the center of mass O of the tumbling object as the origin. B Y B Z B The angular momentum H of the tumbling object is along the OZ axis, and the spin axis of the tumbling object is OZ. B The angle between H and H is the nutation angle θ.

[0017] Based on the despinning pull exerted on the tumbling object by the first and second service satellites, the vertical OZ B The components of the axis determine the torque exerted by the first and second service satellites on the tumbling object to eliminate the nutation angle.

[0018] M t1 =L1×F t1

[0019] M t2 =L2×F t2

[0020] Among them, M t1 M is the torque exerted by the first service satellite on a tumbling object to eliminate the nutation angle. t1 The direction of M is opposite to the direction of the transverse angular momentum. t2 M is the torque exerted by the second service satellite on a tumbling object to eliminate the nutation angle. t2 With M t1 Equal in size and direction; L1 is the distance vector from the center of mass O of the tumbling object to O1; F t1 The despinning force exerted by the first service satellite on the tumbling object along the vertical OZ B The axial component, L2, is the distance vector from the center of mass O of the tumbling object to O2; F t2 The despinning force exerted by the second service satellite on the tumbling object along the vertical OZ B The component along the axial direction; the magnitudes of the anti-spinning forces exerted by the first and second service satellites on the tumbling object are equal, but the directions are opposite.

[0021] Based on the torque applied by the first service satellite to the tumbling object to eliminate nutation angle and the torque applied by the second service satellite to the tumbling object to eliminate nutation angle, the total torque for eliminating nutation angle is obtained as follows:

[0022] M = M t1 +M t2

[0023] Where M is the total torque for eliminating the nutation angle.

[0024] In one embodiment, after eliminating the nutation angle, the third service satellite uses the tether launching system to launch a harpoon to connect the tether to the side of the tumbling object, eliminates the spin angular velocity by controlling the direction and size of the upward force of the tether on the third service satellite, and then drags the tumbling object out of orbit, including:

[0025] After eliminating the nutation angle, the third service satellite uses the tether launching system to launch a harpoon to connect the tether to the side of the tumbling object.

[0026] The third service satellite is controlled by a guidance law to always fly around the tumbling object relative to the spin plane passing through the center of mass of the tumbling object, and the distance from the third service satellite to the center of mass of the tumbling object is constant.

[0027] The electric wheel on the third service satellite tightens the tether to apply a continuous pulling force to the tumbling object, and the size of the pulling force is controlled by a tether pulling force control law to make the spin angular velocity of the tumbling object decrease at a preset rate of change until it converges to zero; then the tumbling object is dragged out of orbit.

[0028] In one embodiment, the conditions under which the third service satellite applies a continuous pulling force to the tumbling object include:

[0029] The direction of the moment generated by the continuous pulling force of the third service satellite on the tumbling object relative to the center of mass of the tumbling object is opposite to the direction of the angular momentum generated by the spin angular velocity, and the size of the moment generated by the continuous pulling force of the third service satellite on the tumbling object relative to the center of mass of the tumbling object is:

[0030] M l = R x F l

[0031] where R is the distance vector from the center of mass O of the tumbling object to the point of action of the continuous pulling force applied by the third service satellite to the tumbling object; F l is the continuous pulling force applied by the third service satellite to the tumbling object, the point of action of F l is the position where the tether is tangent to the side of the tumbling object, and M l is the moment generated by the continuous pulling force applied by the third service satellite to the tumbling object relative to the center of mass of the tumbling object.

[0032] A three-satellite cooperative tethered drag de-spin system for a space tumbling object, the system including three service satellites with maneuvering capability, and a tether launching device installed on the service satellites for de-spinning and dragging the tumbling object out of orbit.

[0033] The first service satellite and the second service satellite are symmetrically distributed relative to the center of mass of the tumbling object, the third service satellite is distributed in the spin plane passing through the center of mass of the tumbling object, and the distance from the first service satellite and the second service satellite to the center of mass of the tumbling object is equal.

[0034] Three service satellites launch a harpoon through a tether launching device to connect a tether to the tumbling object, control the direction of the pulling force of the tether on the three service satellites through a guidance law, control the size of the pulling force of the tether on the three service satellites through a tether pulling force control law, and eliminate the nutation angle and then the spin angular velocity of the tumbling object according to a spin elimination strategy.

[0035] In one embodiment, three service satellites launch a harpoon through a tether launching device to connect a tether to the tumbling object, control the direction of the pulling force of the tether on the three service satellites through a guidance law, control the size of the pulling force of the tether on the three service satellites through a tether pulling force control law, and eliminate the nutation angle and then the spin angular velocity of the tumbling object according to a spin elimination strategy, comprising:

[0036] The first service satellite and the second service satellite respectively launch a harpoon to connect a tether to two points O1 and O2 on the upper and lower surfaces of the tumbling object; wherein the point O1 and the point O2 are respectively the spin axis OZ B The intersection of the positive and negative half-axes and the upper and lower surfaces of the tumbling object.

[0037] The first service satellite and the second service satellite control the direction of the pulsed pulling force of the tether through a guidance law, and control the size of the pulling force of the tether through a tether pulling force control law to eliminate the nutation angle.

[0038] After the nutation angle is eliminated, the third service satellite uses a tether launching system to launch a harpoon to connect a tether to the side of the tumbling object, controls the direction of the continuous pulling force of the tether on the third service satellite through a guidance law, and controls the size of the continuous pulling force of the tether on the third service satellite through a tether pulling force control law to eliminate the spin angular velocity; then, the tumbling object is deorbited.

[0039] In one embodiment, the spin-eliminating pulling force exerted by the first service satellite and the second service satellite on the tumbling object satisfies the condition that:

[0040] An inertial coordinate system O-XYZ and a body coordinate system O-X B Y B Z B are established with the center of mass O of the tumbling object as the coordinate origin; the angular momentum H of the tumbling object is along the OZ B axis direction, and the included angle between the spin axis OZ B and H is the nutation angle θ.

[0041] According to the component of the spin-eliminating pulling force exerted by the first service satellite and the second service satellite on the tumbling object perpendicular to the OZ B axis, the moment of the first service satellite and the second service satellite to eliminate the nutation angle of the tumbling object is determined.

[0042] Mt1 = L1 x F t1

[0043] M t2 = L2 x F t2

[0044] wherein M t1 is the moment of the first service satellite to eliminate the nutation angle of the tumbling object, the direction of M t1 is opposite to the direction of the transverse angular momentum, M t2 is the moment of the second service satellite to eliminate the nutation angle of the tumbling object, the direction of M t2 is the same as the direction of M t1 ; L1 is the distance vector from the center of mass O of the tumbling object to O1; F t1 is the component of the despinning tension of the first service satellite to the tumbling object along the direction perpendicular to OZ B axis, L2 is the distance vector from the center of mass O of the tumbling object to O2; F t2 is the component of the despinning tension of the second service satellite to the tumbling object along the direction perpendicular to OZ B axis; the magnitude of the despinning tension of the first service satellite and the second service satellite to the tumbling object is equal, and the direction is opposite.

[0045] According to the moment of the first service satellite to eliminate the nutation angle of the tumbling object and the moment of the second service satellite to eliminate the nutation angle of the tumbling object, the total moment to eliminate the nutation angle is obtained as follows:

[0046] M = M t1 + M t2

[0047] wherein M is the total moment to eliminate the nutation angle.

[0048] In one of the embodiments, the condition that the continuous tension of the third service satellite to the tumbling object satisfies includes:

[0049] The direction of the moment of the continuous tension of the third service satellite to the tumbling object relative to the center of mass of the tumbling object is opposite to the direction of the angular momentum generated by the spin angular velocity, and the magnitude of the moment of the continuous tension of the third service satellite to the tumbling object relative to the center of mass of the tumbling object is:

[0050] M l = R x F l

[0051] wherein R is the distance vector from the center of mass O of the tumbling object to the action point of the continuous tension of the third service satellite to the tumbling object; F l is the continuous tension of the third service satellite to the tumbling object, and F lThe action point is the position where the tether is tangent to the side of the tumbling object, M l is the moment generated by the continuous pulling force exerted by the third service satellite on the tumbling object relative to the center of mass of the tumbling object.

[0052] The above-mentioned three-satellite cooperative anti-tumbling tethered method and system for a space tumbling object, the method comprising: establishing a three-satellite cooperative anti-tumbling space configuration; the three-satellite cooperative anti-tumbling space configuration is composed of three service satellites with maneuvering capability, the first service satellite and the second service satellite are symmetrically distributed relative to the center of mass of the tumbling object, the distance from the first service satellite and the second service satellite to the center of mass of the tumbling object is equal, and the third service satellite is distributed in the spin plane passing through the center of mass of the tumbling object; the satellite emits a spear through a tether shooting device to connect the tether on the tumbling object, according to the anti-tumbling strategy of eliminating the nutation angle first and then eliminating the spin angular velocity, the tether is used to exert an anti-tumbling moment on the tumbling object, and the anti-tumbling task and the tethered de-orbiting task of the tumbling object are completed under the premise of ensuring the attitude stability of the tumbling object. Compared with other existing contact anti-tumbling schemes, the risk of accidental collision is reduced; through the anti-tumbling strategy of eliminating the nutation angle first and then eliminating the spin angular velocity, the problem of limited anti-tumbling effect of the tether and the net on the tumbling object is solved; compared with the non-contact anti-tumbling, the tether can provide a larger pulling force, reduce the anti-tumbling time, and can perform subsequent tethered operations. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 is a flowchart of the three-satellite cooperative tethered anti-tumbling method for a space tumbling object in one embodiment;

[0054] Figure 2 is a schematic diagram of a three-satellite cooperative anti-tumbling system in another embodiment;

[0055] Figure 3 is an analysis diagram of the nutation angle elimination moment in another embodiment;

[0056] Figure 4 is an analysis diagram of the spin angular velocity elimination moment in another embodiment;

[0057] Figure 5 is a schematic diagram of the anti-tumbling moment for eliminating the nutation angle in another embodiment;

[0058] Figure 6 is a nutation angle response diagram in another embodiment;

[0059] Figure 7 is a schematic diagram of the anti-tumbling moment for eliminating the spin angular velocity in another embodiment;

[0060] Figure 8 is a spin angular velocity response diagram in another embodiment. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0062] In one embodiment, as shown in Figure 1 A three-satellite cooperative anti-tumbling object rope tether de-spinning method is provided, which comprises the following steps:

[0063] Step 100: Establish a three-satellite cooperative de-spinning space configuration; the three-satellite cooperative de-spinning space configuration is composed of three service satellites with maneuvering capability, the first service satellite and the second service satellite are symmetrically distributed relative to the center of mass of the tumbling object, the distance from the first service satellite and the second service satellite to the center of mass of the tumbling object is equal, and the third service satellite is distributed in the spin plane passing through the center of mass of the tumbling object.

[0064] Specifically, the service satellites are first launched into orbit, and guided control is used to make the three service satellites enter a cooperative de-spinning configuration, as shown in Figure 2 The service satellites S1 and S2 are symmetrically distributed relative to the center of mass O of the tumbling object, which is used to eliminate the nutation angle, the included angle between the line of sight direction between the service satellite S1 and the center of mass O of the tumbling object and the direction of the angular momentum vector H of the tumbling object is α, the distances from the service satellites S1 and S2 to the center of mass O of the tumbling object are R1 and R2 respectively, and R1 = R2, the symmetrically distributed configuration can avoid causing the original orbit of the tumbling object to change; the service satellite S3 is used to eliminate the spin angular velocity and is distributed in the spin plane passing through the center of mass O of the tumbling object, and the distance from the service satellite S3 to the center of mass O of the tumbling object is R3. Among them, the service satellites S1, S2 and S3 are the first service satellite, the second service satellite and the third service satellite respectively.

[0065] Step 102: The first service satellite and the second service satellite use the tether launching system to launch a dart to connect the tether to the upper and lower surfaces of the tumbling object, and the direction and size of the pulling force of the tether of the first service satellite and the second service satellite are controlled to eliminate the nutation angle.

[0066] Specifically, the service satellites S1 and S2 respectively launch a dart to connect the tether to the upper and lower surfaces O1 and O2 of the tumbling object; the points O1 and O2 are the intersection points of the positive and negative semi-axes and the upper and lower surfaces of the tumbling object, the spin axis OZ B of the tumbling object, the guidance law is used to control α, R1 and R2 to be constant, the electric wheels on the service satellites S1 and S2 are used to tighten the tether to apply a pulse de-spinning force F1 and F2 to the tumbling object, so that the nutation angle gradually decreases until the nutation angle converges to zero.

[0067] Step 104: After eliminating the nutation angle, the third service satellite uses the tether launching system to launch a dart to connect the tether to the side of the tumbling object, eliminates the spin angular velocity by controlling the direction and size of the upward force of the tether on the third service satellite, and then drags the tumbling object out of orbit.

[0068] Specifically, the service satellite S3 launches a dart to connect the tether to the side of the tumbling object at point O3, which is an intersection of the spin plane of the center of mass O of the tumbling object and the side of the tumbling object, controls the service satellite S3 to fly around the tumbling object in the spin plane of the center of mass O of the tumbling object by a guidance law, and controls R3 to be constant, controls the service satellite S3 to tighten the tether by an electric wheel to apply a continuous pulling force F l to the tumbling object, reduces the spin angular velocity at a desired rate of change until it converges to zero, and finally drags the tumbling object out of orbit.

[0069] The above-mentioned three-satellite cooperative tethered spinning elimination and dragging method for a space tumbling object includes: establishing a three-satellite cooperative spinning elimination space configuration; the three-satellite cooperative spinning elimination space configuration is composed of three service satellites with maneuvering capability, the first service satellite and the second service satellite are symmetrically distributed relative to the center of mass of the tumbling object, the distance from the first service satellite and the second service satellite to the center of mass of the tumbling object is equal, and the third service satellite is distributed in the spin plane of the center of mass of the tumbling object; the satellite launches a dart to connect the tether to the tumbling object by a tether launching device, according to a spinning elimination strategy of first eliminating the nutation angle and then eliminating the spin angular velocity, applies a spinning elimination moment to the tumbling object by the tether, and completes the spinning elimination task and the dragging out of orbit task of the tumbling object on the premise of ensuring the stability of the attitude of the tumbling object. Compared with other existing contact spinning elimination schemes, the risk of accidental collision is reduced; through the spinning elimination strategy of first eliminating the nutation angle and then eliminating the spin angular velocity, the problem of limited spinning elimination effect of the tether and the net on the tumbling object is solved; compared with non-contact spinning elimination, the tether can provide a larger pulling force, reduce the spinning elimination time, and enable subsequent dragging operation.

[0070] In one embodiment, step 102 includes: the first service satellite and the second service satellite respectively launch a dart to connect the tether to two points O1 and O2 on the upper and lower surfaces of the tumbling object; wherein the point O1 and the point O2 are respectively the intersection of the positive and negative half-axes with the upper and lower surfaces of the tumbling object; the direction of the upward force of the tether on the first service satellite and the second service satellite is controlled by a guidance law, and the size of the upward force of the tether on the first service satellite and the second service satellite is controlled by a tether pulling force control law to eliminate the nutation angle. B

[0071] ​In one of the embodiments, the direction of the pull force of the tether between the first service satellite and the second service satellite is controlled by a guidance law, and the size of the pull force of the tether between the first service satellite and the second service satellite is controlled by a tether tension control law to eliminate the nutation angle; including: the angle between the direction of the line of sight between the first service satellite and the center of mass of the tumbling object and the direction of the angular momentum vector H of the tumbling object, the distance from the first service satellite to the center of mass of the tumbling object, and the distance from the second service satellite to the center of mass of the tumbling object are kept unchanged by the guidance law; the electric wheels on the first service satellite and the second service satellite tighten the tether to exert a pulsed despinning pull force on the tumbling object, and the size of the despinning pull force is controlled by the tether tension control law to make the nutation angle decrease at a preset rate until it converges to zero.

[0072] In one of the embodiments, the conditions satisfied by the despinning pull force exerted on the tumbling object by the first service satellite and the second service satellite include: establishing an inertial coordinate system O-XYZ and a body coordinate system O-X B Y B Z B with the center of mass O of the tumbling object as the coordinate origin; the angular momentum H of the tumbling object is along the OZ axis direction, and the angle between the spin axis OZ B of the tumbling object and H is the nutation angle θ; according to the component of the despinning pull force exerted on the tumbling object by the first service satellite and the second service satellite perpendicular to the OZ B axis, the moment of the force exerted on the tumbling object by the first service satellite and the second service satellite to eliminate the nutation angle is determined as:

[0073] M t1 =L1×F t1

[0074] M t2 =L2×F t2

[0075] wherein, M t1 is the moment of the force exerted on the tumbling object by the first service satellite to eliminate the nutation angle, the direction of M t1 is opposite to the direction of the transverse angular momentum, M t2 is the moment of the force exerted on the tumbling object by the second service satellite to eliminate the nutation angle, and M t2 is equal in size and direction to M t1 ; L1 is the distance vector from the center of mass O of the tumbling object to O1; F t1 is the component of the despinning pull force exerted on the tumbling object by the first service satellite along the direction perpendicular to the OZ B axis, and L2 is the distance vector from the center of mass O of the tumbling object to O2; F t2 is the component of the despinning pull force exerted on the tumbling object by the second service satellite along the direction perpendicular to the OZ BThe component along the axial direction; the magnitudes of the anti-spinning forces exerted by the first and second service satellites on the tumbling object are equal, but the directions are opposite.

[0076] Based on the torque applied by the first service satellite to the tumbling object to eliminate nutation angle and the torque applied by the second service satellite to the tumbling object to eliminate nutation angle, the total torque for eliminating nutation angle is obtained as follows:

[0077] M = M t1 +M t2

[0078] Where M is the total torque for eliminating the nutation angle.

[0079] Specifically, service satellites S1 and S2 use guidance laws to keep α, R1, and R2 constant, thus orbiting the tumbling object. They then launch projectiles that hit points O1 and O2 on the tumbling object. During the orbiting process, when the positions of service satellites S1 and S2 relative to the tumbling object meet the conditions for applying tension to eliminate the nutation angle, an electric wheel tightens the tether, applying a pulsed tension to the tumbling object to reduce the nutation angle until it converges to zero. If the tension application conditions are not met, the electric wheel releases the tether, putting it in a slack state.

[0080] The principle for eliminating nutation angle is as follows:

[0081] If a tumbling object is considered a dynamically axisymmetric rigid body, and its spin angular velocity remains constant, then according to the formula for calculating the nutation angle... And the formula for calculating the angular momentum of a tumbling object: H = J t ω t +J z ω z e z Decrease the transverse angular momentum J t ω t This will reduce the nutation angle;

[0082] like Figure 3 As shown, an inertial coordinate system O-XYZ and a body coordinate system OX are established with the center of mass O of the tumbling object as the origin. B Y B Z B The angular momentum H of the tumbling object is along the OZ axis, and the spin axis of the tumbling object is OZ. B The angle between H and H is the nutation angle θ;

[0083] H along OZ B Axis and Vertical OZ B Decomposing along the axis, we obtain the spin angular velocity ω of the tumbling object. z The generated spin angular momentum J z ω z With lateral angular velocity ω tThe generated transverse angular momentum J t ω t , the nutation angle needs to be eliminated by generating a torque opposite to the transverse angular momentum J t ω t of the rolling object on the center of mass O of the rolling object, so the directions of the pulling forces F1 and F2 need to satisfy the following conditions:

[0084] To facilitate the analysis of the direction of the pulling force on the tether, it is assumed that the tether is in a tension state, so the pulling force F1 applied by the tether to the rolling object is decomposed along the OZ B axis and the direction perpendicular to the OZ B axis to obtain the component F B perpendicular to the OZ t1 axis and the component F B along the OZ n1 axis, the angle between F1 and F t1 is β, the distance vector L points from the center of mass O of the rolling object to O1, and the direction of M t1 is determined by the moment calculation formula M t1 = L x F t1 and the right-hand rule, when M t1 is opposite to J t ω t , F t1 is perpendicular to the plane formed by the OZ B axis and H, at this time, the pulling force generated by the electric wheel to tighten the tether can eliminate J t ω t , thereby eliminating the nutation angle. The application conditions of the pulling force F2 are the same as those of F1, and will not be described again.

[0085] The component F B along the OZ n1 axis passes through the center of mass O of the rolling object, which will change the original orbit of the rolling object, which is not conducive to the fly-around of the service satellite to the rolling object, by the symmetrically distributed service satellite S2 relative to the center of mass O of the rolling object, a pulling force F2 equal in size and opposite in direction to the pulling force F1 is applied, and a component F n1 equal in size and opposite in direction to F n2 is generated, so the effects of F n1 and F n2 are offset, avoiding changes to the original orbit of the rolling object, and at the same time, a moment M l equal in size and in the same direction as M t2 is generated, so the total moment for eliminating the nutation angle is generated by the service satellites S1 and S2, that is, M = M t1 + M t2 Since the time satisfying the above pulling force application condition is discrete during the fly-around, the spin-eliminating pulling force applied by the service satellites S1 and S2 is a pulsed pulling force.

[0086] In one embodiment, step 104 includes: after eliminating the nutation angle, the third service satellite uses a tethered ejection system to launch a spear to connect the tether to the side of the tumbling object; the guidance law controls the third service satellite to always fly around the tumbling object in the spin plane passing through the center of mass of the tumbling object, and the distance between the third service satellite and the center of mass of the tumbling object remains unchanged; the electric wheel on the third service satellite tightens the tether to apply a continuous pulling force to the tumbling object, and the pulling force is controlled by the tether tension control law to reduce the spin angular velocity of the tumbling object at a preset rate of change until it converges to zero; then, the tumbling object is dragged off the track.

[0087] In one embodiment, the condition for the third service satellite to apply a continuous pulling force to the tumbling object includes: the direction of the torque generated by the continuous pulling force applied by the third service satellite to the tumbling object relative to the center of mass of the tumbling object is opposite to the direction of the angular momentum generated by the spin angular velocity; and the magnitude of the torque generated by the continuous pulling force applied by the third service satellite to the tumbling object relative to the center of mass of the tumbling object is:

[0088] M l =R×F l

[0089] Where R is the distance vector from the center of mass O of the tumbling object to the point of application of the continuous pulling force exerted on the tumbling object by the third service satellite; F l For the continuous pulling force exerted by the third service satellite on the tumbling object, F l The point of application is the position where the tether is tangent to the side of the rolling object, M l The torque generated relative to the center of mass of the tumbling object by the continuous pulling force exerted by the third service satellite on the tumbling object.

[0090] Specifically, the service satellite S3 uses a guidance law to control its orbit around the tumbling object in the spin plane of the center of mass O of the tumbling object. During the orbit, R3 is kept constant. The service satellite S3 launches a spear to attach a tether to point O3 on the side of the tumbling object. The tether wraps around the side of the tumbling object as it rotates. When the electric wheel releases the tether, the tension on the tether is controlled by a tension control law to reduce the spin angular velocity of the tumbling object at the desired rate of change, eventually converging to zero to complete the despinning. Finally, the towing deorbiting operation is performed.

[0091] The principle for eliminating spin angular velocity is as follows:

[0092] like Figure 4 As shown, the distance vector R points from the center of mass O of the tumbling object to F. l Point of application, F l The point of application is the position where the tether is tangent to the side of the tumbling object, R and F l The tension F applied by the service satellite S3 is orthogonal and the magnitude of R remains constant.l The moment generated by the force relative to the center of mass O of the tumbling object is M l = R x F l , M l The angular momentum J generated by the spin angular velocity z ω z is opposite to the direction of the force F It can be seen that the spin angular velocity gradually decreases.

[0093] In the process of eliminating the spin angular velocity, the service satellite S3 is controlled to remain in the spin plane of the tumbling object by a guidance law, and the tension force F l The moment M generated by the force relative to the center of mass of the tumbling object l is always opposite to the spin angular momentum J z ω z of the tumbling object, so the tension force F l is a continuous tension force.

[0094] It should be understood that although each step in the flowchart of Figure 1 is shown in sequence according to the direction of the arrow, these steps are not necessarily executed in sequence according to the direction of the arrow. Unless otherwise specified herein, there is no strict order limitation for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1 At least part of the steps in may include multiple sub-steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily sequential, but can be alternately executed with at least part of other steps or sub-steps or stages of other steps.

[0095] Figure 2 In one embodiment, as shown in , a three-satellite cooperative space tumbling object tethered de-spinning system is provided, which includes three service satellites with maneuvering capability, and a tether ejection device is installed on the service satellite for de-spinning and tethering the tumbling object.

[0096] The first service satellite and the second service satellite are symmetrically distributed relative to the center of mass of the tumbling object, and the third service satellite is distributed in the spin plane passing through the center of mass of the tumbling object, and the distance from the first service satellite and the second service satellite to the center of mass of the tumbling object is equal.

[0097] The three service satellites connect the tether on the tumbling object through the spear ejection device of the tether ejection device, control the direction of the tension force on the tether of the three service satellites through a guidance law, control the size of the tension force on the tether of the three service satellites through a tether tension force control law, and de-spin the tumbling object according to the de-spinning strategy of eliminating the nutation angle first and then the spin angular velocity.

[0098] In one embodiment, three service satellites launch spears via a tethered ejection device to connect tethers to a tumbling object. A guidance law controls the direction of the tension on the tethers of the three service satellites, and a tether tension control law controls the magnitude of the tension on the tethers. The tumbling object is despinned according to a despinning strategy that first eliminates the nutation angle and then the spin angular velocity. This includes: the first and second service satellites respectively launch spears to connect tethers to two points O1 and O2 on the upper and lower surfaces of the tumbling object; where points O1 and O2 are the spin axes OZ of the tumbling object. B The intersection of the positive and negative half-axis with the upper and lower surfaces of the tethered object; the direction of the pulsed tension on the tethers of the first and second service satellites is controlled by the guidance law, and the magnitude of the tension on the tethers of the first and second service satellites is controlled by the tether tension control law to eliminate the nutation angle; after eliminating the nutation angle, the third service satellite uses the tether ejection system to launch a spear to connect the tether to the side of the tethered object, the direction of the continuous tension on the tether of the third service satellite is controlled by the guidance law, and the magnitude of the continuous tension on the tether of the third service satellite is controlled by the tether tension control law to eliminate the spin angular velocity; then, the tethered object is dragged off the track.

[0099] In one embodiment, the despinning force applied to the tumbling object by the first and second service satellites satisfies the following conditions: establishing an inertial coordinate system O-XYZ and a body coordinate system OX with the center of mass O of the tumbling object as the origin. B Y B Z B The angular momentum H of the tumbling object is along the OZ axis, and the spin axis of the tumbling object is OZ. B The angle between H and the nutation angle θ; the despinning force exerted on the tumbling object by the first and second service satellites is perpendicular to OZ. B The components of the axis determine the torque exerted by the first and second service satellites on the tumbling object to eliminate the nutation angle:

[0100] M t1 =L1×F t1

[0101] M t2 =L2×F t2

[0102] Among them, M t1 M is the torque exerted by the first service satellite on a tumbling object to eliminate the nutation angle. t1 The direction of M is opposite to the direction of the transverse angular momentum. t2 M is the torque exerted by the second service satellite on a tumbling object to eliminate the nutation angle. t2 With M t1 Equal in size and direction; L1 is the distance vector from the center of mass O of the tumbling object to O1; Ft1 The despinning pull exerted by the first service satellite on the tumbling object has a component along the vertical OZ B axis, L2 is the distance vector from the center of mass O of the tumbling object to O2; F t2 The despinning pull exerted by the second service satellite on the tumbling object has a component along the vertical OZ B axis; the despinning pulls exerted by the first service satellite and the second service satellite on the tumbling object are equal in magnitude and opposite in direction.

[0103] The total moment for eliminating the nutation angle is obtained according to the moment for eliminating the nutation angle exerted by the first service satellite on the tumbling object and the moment for eliminating the nutation angle exerted by the second service satellite on the tumbling object:

[0104] M = M t1 + M t2

[0105] Wherein, M is the total moment for eliminating the nutation angle.

[0106] In one of the embodiments, the conditions that the continuous pull exerted by the third service satellite on the tumbling object satisfies include: the direction of the moment generated by the continuous pull exerted by the third service satellite on the tumbling object relative to the center of mass of the tumbling object is opposite to the direction of the angular momentum generated by the spin angular velocity, and the magnitude of the moment generated by the continuous pull exerted by the third service satellite on the tumbling object relative to the center of mass of the tumbling object is:

[0107] M l = R x F l

[0108] Wherein, R is the distance vector from the center of mass O of the tumbling object to the point of action of the continuous pull exerted by the third service satellite on the tumbling object; F l is the continuous pull exerted by the third service satellite on the tumbling object, and the point of action of F l is the position where the tether is tangent to the side surface of the tumbling object, and M l is the moment generated by the continuous pull exerted by the third service satellite on the tumbling object relative to the center of mass of the tumbling object.

[0109] In one of the embodiments, the tumbling object is selected as an elongated satellite distributed in the geostationary orbit, and the moment of inertia and the angular velocity information of the tumbling object are shown in Table 1. The inertial coordinate system O-XYZ and the body coordinate system O-X B Y B Z B are respectively established with the center of mass O of the tumbling object as the coordinate origin, and the direction of the spin angular velocity is along the positive direction of the OZ B axis.

[0110] Table 1 Information of the tumbling object

[0111] I x (kg·m 2 )]]> I y (kg·m 2 )]]> I z (kg·m 2 )]]> x (rad / s) ​ y (rad / s) ​ z (rad / s) ​ 50 50 20 0.01 0.02 1

[0112] The specific implementation steps are as follows:

[0113] Step 1: Eliminate the nutation angle:

[0114] As shown in Figure 2 , the service satellites S1 and S2 fly around the tumbling object, are symmetrically distributed relative to the center of mass O of the tumbling object, the angle between the line of sight direction between the service satellite S1 and the center of mass O of the tumbling object and the direction of the angular momentum vector H of the tumbling object is α, the distances from the service satellites S1 and S2 to the center of mass O of the tumbling object are R1 and R2, and R1 = R2, and α, R1 and R2 are controlled to be constant by a guidance law. The service satellites S1 and S2 respectively emit spears to connect the tethers on the upper and lower surfaces O1 and O2 of the tumbling object; wherein the points O1 and O2 are the intersection points of the positive and negative half axes of the spin axis of the tumbling object and the upper and lower surfaces thereof.

[0115] As shown in Figure 3 , taking the service satellite S1 as an example, when the position of the service satellite makes the tension force F1 generated by the tethers in the vertical OZ B axis has a component F t1 , the torque M t1 generated by the component F t on the center of mass O of the tumbling object is opposite to the transverse angular momentum J t of the tumbling object, the tension force of the tethers is tightened by the electric wheel to exert a pulsed action on the tumbling object, and the size of the tension force is controlled by a tether tension force control law, so that the nutation angle is reduced until it converges to zero. The service satellite S2 exerts tension force on the tumbling object under the same condition as S1, which will not be described again. F t1 The size of the despinning torque M t generated relative to the center of mass O of the tumbling object is shown in Figure 5 , and the relationship between the nutation angle and the transverse angular velocity of the tumbling object is shown in Figure 6 . In the figure, Figure 5 the horizontal axis is time, and the vertical axis is the size of the despinning torque; Figure 6 the horizontal axis is time, and the vertical axis is the size of the nutation angle.

[0116] Step 2: Eliminate the spin angular velocity:

[0117] When the nutation angle is reduced to zero, the service satellite S3 enters the orbit around the tumbling object, as shown in Figure 4 , and the service satellite S3 emits a spear to connect the tether at the side O3 of the tumbling object. As the tumbling object rotates, the tether is gradually wound around the tumbling object. The service satellite S3 is always kept in the spin plane of the center of mass O of the tumbling object and R3 is constant by a guidance law, and the continuous tension force F l is exerted on the tumbling object by the electric wheel to tighten the tether, and the size of the tension force is controlled by a tether tension force control law.l The spin angular velocity decreases uniformly to zero. Finally, the rolling object is dragged off the orbit by a tether and enters the grave orbit. l The despinning moment M generated relative to the center of mass O of the rolling object l The size is as shown in Figure 7 The spin angular velocity of the rolling object changes as shown in Figure 8 The horizontal axis is time, and the vertical axis is the size of the despinning moment; Figure 7 The horizontal axis is time, and the vertical axis is the size of the spin angular velocity. Figure 8 The horizontal axis is time, and the vertical axis is the size of the despinning moment;

[0118] The technical features of the above embodiments can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not contradict, they should be considered as falling within the scope of the present disclosure.

[0119] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for de-spinning a tethered object tumbling in space using a three-star collaborative system, characterized in that, The method includes: A three-satellite cooperative despin configuration is established; the three-satellite cooperative despin configuration consists of three maneuverable service satellites, the first and second service satellites are symmetrically distributed with respect to the center of mass of the tumbling object, the first and second service satellites are equidistant from the center of mass of the tumbling object, and the third service satellite is distributed in the spin plane passing through the center of mass of the tumbling object. The first and second service satellites use a tethered ejection system to launch spears and attach tethers to the upper and lower surfaces of the tumbling object. Nucleation angle is eliminated by controlling the direction and magnitude of the tension on the tethers of the first and second service satellites. After eliminating the nutation angle, the third service satellite uses a tethered ejection system to launch a spear that attaches a tether to the side of the tumbling object. By controlling the direction and magnitude of the tension on the tether of the third service satellite, the spin angular velocity is eliminated, and then the tumbling object is dragged off the orbit.

2. The method according to claim 1, characterized in that, The first and second service satellites utilize a tethered ejection system to launch spears, with the tethers attached to the upper and lower surfaces of the tumbling object. Nulling angle is eliminated by controlling the direction and magnitude of the tension on the tethers of the first and second service satellites, including: The first and second service satellites respectively launch spears to attach the tether to two points on the upper and lower surfaces of the tumbling object. , ; midpoint ,point The spin axes of the tumbling objects are respectively The intersection points of the positive and negative half-axis with the upper and lower surfaces of the rolling object; Nucleation angle is eliminated by controlling the direction of the tension on the tethers of the first and second service satellites using a guidance law, and by controlling the magnitude of the tension on the tethers of the first and second service satellites using a tether tension control law.

3. The method according to claim 2, characterized in that, Nulling angle is eliminated by controlling the direction of the tension on the tethers of the first and second serving satellites using a guidance law, and by controlling the magnitude of the tension on the tethers of the first and second serving satellites using a tether tension control law; including: The guidance law keeps the angle between the line of sight between the first service satellite and the center of mass of the tumbling object and the direction of the angular momentum vector H of the tumbling object, the distance from the first service satellite to the center of mass of the tumbling object, and the distance from the second service satellite to the center of mass of the tumbling object constant. The electric wheels on the first and second service satellites tighten the tethers, applying pulsed despinning force to the tumbling object. The magnitude of the despinning force is controlled by the tether tension control law, causing the nutation angle to decrease at a preset rate of change until it converges to zero.

4. The method according to claim 3, characterized in that, The conditions that the despinning pull exerted on the tumbling object by the first and second service satellites must satisfy include: With the center of mass of the rolling object Establish inertial coordinate systems for the origin. With body coordinate system The angular momentum H of a tumbling object along... Axial direction, the spin axis of the tumbling object The angle between H and H is the nutation angle. ; Based on the despinning pull exerted vertically on the tumbling object by the first and second service satellites The components of the axis determine the torque exerted by the first and second service satellites on the tumbling object to eliminate the nutation angle; in, The torque exerted by the primary service satellite on a tumbling object to eliminate nutation angle. The direction is opposite to the direction of the transverse angular momentum. The torque exerted by the second service satellite on a tumbling object to eliminate the nutation angle. and Equal in size and in the same direction; From the center of mass of the tumbling object point to The distance vector; The despinning force exerted by the first service satellite on the tumbling object along the vertical direction Components in the axial direction, From the center of mass of the tumbling object point to The distance vector; The despinning force exerted by the second service satellite on the tumbling object along the vertical direction The component along the axial direction; the magnitudes of the anti-spin pull exerted by the first and second service satellites on the tumbling object are equal, but the directions are opposite; Based on the torque applied by the first service satellite to the tumbling object to eliminate nutation angle and the torque applied by the second service satellite to the tumbling object to eliminate nutation angle, the total torque for eliminating nutation angle is obtained as follows: in, To eliminate the total torque of the nutation angle.

5. The method according to claim 1, characterized in that, After eliminating the nutation angle, the third service satellite uses a tethered ejection system to launch a spear that attaches a tether to the side of the tumbling object. By controlling the direction and magnitude of the tension on the tether, the spin angular velocity is eliminated. Then, the tumbling object is towed off orbit, including: After eliminating the nutation angle, the third service satellite uses a tethered ejection system to launch a spear and attach the tether to the side of the tumbling object; The guidance law controls the third service satellite to always fly around the tumbling object in the spin plane passing through the center of mass of the tumbling object, and the distance between the third service satellite and the center of mass of the tumbling object remains unchanged. The electric wheel on the third service satellite tightens the tether to apply a continuous pulling force to the tumbling object. The magnitude of the pulling force is controlled by the tether tension control law, so that the spin angular velocity of the tumbling object decreases at a preset rate of change until it converges to zero. Then, the tumbling object is dragged off the orbit.

6. The method according to claim 5, characterized in that, The conditions that a third-service satellite must satisfy to apply a continuous pulling force to a tumbling object include: The direction of the torque generated by the third service satellite applying a continuous pulling force to the tumbling object relative to the center of mass of the tumbling object is opposite to the direction of the angular momentum generated by the spin angular velocity. The magnitude of the torque generated by the third service satellite applying a continuous pulling force to the tumbling object relative to the center of mass of the tumbling object is: in, From the center of mass of the tumbling object The distance vector pointing to the point of application of the continuous pulling force exerted by the third service satellite on the tumbling object; The continuous pulling force exerted by the third service satellite on the tumbling object. The point of application is where the rope is tangent to the side of the rolling object. The torque applied by the third service satellite to the tumbling object to eliminate its spin angular velocity.

7. A three-star collaborative system for tethered towing and de-spinning of a tumbling object in space, characterized in that, The system includes three maneuverable service satellites equipped with tethered ejection devices for despinning and towing trolling objects off the track. The first and second service satellites are symmetrically distributed with respect to the center of mass of the tumbling object, and the third service satellite is distributed in the spin plane passing through the center of mass of the tumbling object. The first and second service satellites are equidistant from the center of mass of the tumbling object. Three service satellites launch spears via a tethered catapult to attach tethers to a tumbling object. The direction of the tension on the tethers is controlled by a guidance law, and the magnitude of the tension is controlled by a tether tension control law. The tumbling object is despinned according to a despinning strategy that first eliminates the nutation angle and then the spin angular velocity.

8. The system according to claim 7, characterized in that, Three service satellites launch spears via a tethered ejection system, attaching tethers to a tumbling object. The direction of the tension on the tethers is controlled by a guidance law, and the magnitude of the tension is controlled by a tether tension control law. The tumbling object is despinned according to a despinning strategy that first eliminates the nutation angle and then the spin angular velocity, including: The first and second service satellites respectively launch spears to attach the tether to two points on the upper and lower surfaces of the tumbling object. , ; midpoint ,point The spin axes of the tumbling objects are respectively The intersection points of the positive and negative half-axis with the upper and lower surfaces of the rolling object; The nutation angle is eliminated by controlling the direction of the pulsed tension on the tethers of the first and second service satellites through the guidance law and controlling the magnitude of the tension on the tethers of the first and second service satellites through the tether tension control law. After eliminating the nutation angle, the third service satellite uses a tethered ejection system to launch a spear that connects the tether to the side of the tumbling object. The direction of the continuous tension on the tether of the third service satellite is controlled by the guidance law, and the magnitude of the continuous tension on the tether of the third service satellite is controlled by the tether tension control law to eliminate the spin angular velocity. Then, the tumbling object is dragged off the orbit.

9. The system according to claim 8, characterized in that, The conditions that the despinning pull exerted on the tumbling object by the first and second service satellites must satisfy include: With the center of mass of the rolling object Establish inertial coordinate systems for the origin. With body coordinate system The angular momentum H of a tumbling object along... Axial direction, the spin axis of the tumbling object The angle between H and H is the nutation angle. ; Based on the despinning pull exerted vertically on the tumbling object by the first and second service satellites The components of the axis determine the torque exerted by the first and second service satellites on the tumbling object to eliminate the nutation angle; in, The torque exerted by the primary service satellite on a tumbling object to eliminate nutation angle. The direction is opposite to the direction of the transverse angular momentum. The torque exerted by the second service satellite on a tumbling object to eliminate the nutation angle. and Equal in size and in the same direction; From the center of mass of the tumbling object point to The distance vector; The despinning force exerted by the first service satellite on the tumbling object along the vertical direction Components in the axial direction, From the center of mass of the tumbling object point to The distance vector; The despinning force exerted by the second service satellite on the tumbling object along the vertical direction The component along the axial direction; the magnitudes of the anti-spin pull exerted by the first and second service satellites on the tumbling object are equal, but the directions are opposite; Based on the torque applied by the first service satellite to the tumbling object to eliminate nutation angle and the torque applied by the second service satellite to the tumbling object to eliminate nutation angle, the total torque for eliminating nutation angle is obtained as follows: in, To eliminate the total torque of the nutation angle.

10. The system according to claim 8, characterized in that, The conditions that a third-service satellite must satisfy to apply a continuous pulling force to a tumbling object include: The direction of the torque generated by the third service satellite applying a continuous pulling force to the tumbling object relative to the center of mass of the tumbling object is opposite to the direction of the angular momentum generated by the spin angular velocity. The magnitude of the torque generated by the third service satellite applying a continuous pulling force to the tumbling object relative to the center of mass of the tumbling object is: in, From the center of mass of the tumbling object The distance vector pointing to the point of application of the continuous pulling force exerted by the third service satellite on the tumbling object; The continuous pulling force exerted by the third service satellite on the tumbling object. The point of application is where the rope is tangent to the side of the rolling object. The torque generated relative to the center of mass of the tumbling object by the continuous pulling force exerted by the third service satellite on the tumbling object.

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