Space non-cooperative target autonomous attachment convex trajectory guidance method

Abstract

This invention discloses a method for autonomous attachment of a non-cooperative space target using a convex trajectory, belonging to the field of deep space exploration technology. The method involves establishing the dynamic equations and three-dimensional convex trajectory constraints of the detector in a fixed coordinate system on the surface of a non-cooperative space target. A dynamic vertical plane coordinate system is established, and the x-axis and y-axis coordinate information are equivalently transformed to relax the three-dimensional convex trajectory constraints. The equality constraints with curvature relaxation terms are rewritten in the form of a curvature sliding surface, ensuring that the detector moves along a geometrically convex trajectory when the detector system state is located on the sliding surface. Based on the curvature sliding surface, a curvature sliding mode feedback guidance law is designed to enable the detector system state to converge to the sliding surface within a finite time and move along the sliding surface, maintaining the convex trajectory state to complete precise attachment at a preset time, thus improving attachment safety. This invention improves resistance to initial state deviations and dynamic environmental disturbances by efficiently switching the sliding mode control term sat(s).

Description

Technical Field

[0001] This invention relates to a method for autonomous attachment of convex trajectories to non-cooperative targets in space, belonging to the field of deep space exploration technology. Background Technology

[0002] With the development of deep space exploration technology, approach and attachment detection of non-cooperative space targets such as small celestial bodies, defunct satellites, and space debris has become a research focus. During the approach and attachment process to non-cooperative space targets, the complex disturbances of the space environment necessitate the design of robust guidance laws to achieve precise attachment of the probe to the target's surface. Furthermore, the probe often encounters various obstacles during its approach and attachment to the target, posing a threat to its safety and increasing the difficulty of the attachment task. A trajectory curvature guidance method based on an energy-optimal feedback guidance law ensures the probe is guided along a geometrically convex trajectory by controlling the trajectory curvature function. This method is beneficial for improving the probe's obstacle avoidance capabilities in complex space environments. Summary of the Invention

[0003] The technical problem to be solved by the space non-cooperative target autonomous attachment convex trajectory guidance method disclosed in this invention is: on the basis of basic curvature guidance, the three-dimensional convex trajectory constraint is equivalently transformed and relaxed to construct a curvature sliding surface that satisfies the three-dimensional convex trajectory constraint, so as to ensure that when the detector system state is located on the sliding surface, the detector moves along the geometric convex trajectory. Based on the curvature sliding surface, a curvature sliding feedback guidance law is designed to realize that the detector system state converges to the sliding surface in a finite time and moves along the sliding surface, maintaining the convex trajectory state to complete accurate attachment at a preset time, which has higher safety. It has the following advantages: (1) It ensures that the detector completes accurate attachment in the convex trajectory state at a preset time, effectively reducing the risk of collision with convex obstacles and ensuring that the detector has high safety. (2) It can achieve accurate attachment when there is a deviation in the initial state of the detector and interference in the dynamic environment, with good accuracy and robustness. (3) The guidance law is an analytical guidance law with high solution efficiency, which can improve the real-time performance of the guidance law on the detector's onboard computer.

[0004] The objective of this invention is achieved through the following technical solution.

[0005] This invention discloses a method for autonomous attachment of a non-cooperative target in space using a convex trajectory guidance system. It establishes the dynamic equations and three-dimensional convex trajectory constraints of the detector in a fixed coordinate system on the surface of the non-cooperative target. A dynamic vertical plane coordinate system is established, and the x-axis and y-axis coordinate information are equivalently transformed to relax the three-dimensional convex trajectory constraints. The equality constraints with curvature relaxation terms are rewritten in the form of a curvature sliding surface, ensuring that the detector moves along a geometrically convex trajectory when the detector system state is located on the sliding surface. Based on the curvature sliding surface, a curvature sliding feedback guidance law is designed to enable the detector system state to converge to the sliding surface within a finite time and move along the sliding surface, maintaining the convex trajectory state to complete precise attachment at a preset time, thus improving attachment safety.

[0006] The present invention discloses a method for autonomous attachment of convex trajectories to non-cooperative targets in space, comprising the following steps:

[0007] Step 1: Establish a fixed rectangular coordinate system on the surface of the non-cooperative target in space, and establish the detector dynamics equations and three-dimensional convex trajectory constraints in this coordinate system.

[0008] A rectangular coordinate system O-XYZ is established on the surface of the non-cooperative target in space with the target attachment point as the origin O. The Z-axis is perpendicular to the local ground plane at the location of the attachment point, and its positive direction points to the outside of the surface of the non-cooperative target in space. The X-axis is in the local plane at the location of the attachment point and coincides with the cross product vector of the positive direction of the Z-axis and the rotation direction of the non-cooperative target in space. The Y-axis, together with the X-axis and Z-axis, forms a right-handed coordinate system.

[0009] When the probe moves on the surface-fixed system, it is mainly subjected to the control force generated by the engine and the gravitational force of space. The dynamic equation of the probe system is as follows:

[0010]

[0011] Where r = [x, y, z] T and v = [v x ,v y ,v z ] T Let T represent the position and velocity of the detector under surface rigidity, respectively, where T = [T x ,T y ,T z ] T and a=[a x ,a y ,a z ] T Let g and m represent the triaxial components of the detector's control force and control acceleration in the surface-fixed system, respectively; g is the gravitational force acting on the detector; m is the mass of the detector; and I is the mass of the detector. sp G represents the engine's specific impulse. e This is the gravitational acceleration at sea level on Earth.

[0012] When a probe moves along a geometrically convex trajectory towards a non-cooperative target in space, the probability of collision with space obstacles can be reduced, thus improving the probe's safety in space. In three-dimensional space, the geometric constraints of the convex trajectory are...

[0013]

[0014] When the initial state of the detector does not satisfy the three-dimensional convex trajectory constraint shown in equation (2), the detector state is quickly transformed into a convex trajectory state by constructing a curvature sliding mode feedback guidance law in the subsequent step 4, and the convex trajectory state is maintained until the target attachment point is reached.

[0015] Step 2: Establish a dynamic vertical plane coordinate system, perform equivalent transformation on the x-axis and y-axis coordinate information, and then relax the constraints of the three-dimensional convex trajectory to transform the original three-dimensional convex trajectory inequality constraints into equality constraints containing curvature relaxation terms, which facilitates the design of the curvature sliding surface in Step 3.

[0016] Define a dynamic vertical plane coordinate system X with a fixed origin and attachment points. D OZ D Z D The X axis is consistent with the Z axis, and the X axis is consistent with the Z axis. D Axis and vector [x,y,0] T Align it and point it in the positive x-axis direction, using X D OZ D The coordinate system performs an equivalent transformation of the x-axis and y-axis information.

[0017] definition v D :=dx D / dt and Equation (2) is converted to

[0018]

[0019] Detector in X D The position component of the axis x D and velocity component v D The expressions are respectively

[0020]

[0021]

[0022] After equivalent transformation, the detector's attachment trajectory in three-dimensional space is convex, which is equivalent to the trajectory in X. D OZ D The curvature in the plane is negative. Applying inequality constraint relaxation to equation (3), when x... D When <0, and the attachment trajectory is convex, v satisfies D>0; when x D When >0, and the attachment trajectory is convex, v satisfies D <0, equation (3) is transformed into

[0023]

[0024] Relaxing the constraints of equation (6), we define φ = [φ D ,φ *T ] T =[φ D ,φ x ,φ y ,φ z ] T Let be the curvature relaxation term,

[0025]

[0026] When φ D >φ z When >0, geometric constraints of three-dimensional convex trajectory exist

[0027]

[0028] The geometric convex trajectory constraint shown in equation (3) is satisfied.

[0029] Step 3: Transform the equality constraints containing curvature relaxation terms in Step 2 into a curvature sliding surface form. The curvature sliding surface ensures the detector satisfies the geometric convex trajectory constraints in three-dimensional space, and that the detector's position and velocity are within the range of t... f It converges to 0 at every moment.

[0030] Define s = [s x ,s y ,s z ] T and Λ=diag(λ D ,λ D ,λ z ), and design the following curvature sliding surface.

[0031]

[0032] Let λ D >λ z When >0, and the detector system state is located on the sliding surface (s=0), the curvature relaxation term φ = [φ D ,φ z ] T satisfy

[0033]

[0034]

[0035] Satisfy the geometric convex trajectory constraints in three-dimensional space to ensure that the detector is in X D OZ D The curvature in the plane is negative. This is due to the curvature relaxation term φ. * The existence of singular values ​​at x, y, z = 0 transforms the sliding surface into an equivalent form.

[0036]

[0037] When s = 0, equation (12) is rewritten as follows:

[0038]

[0039] When using the differential form, equation (13) is transformed into

[0040]

[0041] Integrating equation (14), we get

[0042]

[0043] in Let r be the initial value of the detector system when s = 0. Differentiating equation (15) yields...

[0044]

[0045] Where I is the identity matrix. Combining equations (15)-(16), we get that as long as λ D >λ z >1, the detector will be in X D OZ D The curvature remains negative in the plane, and the position and velocity are constant at t. f It converges to 0 at every moment.

[0046] Step 4: Using the sliding surface designed in Step 3, establish a guidance law for autonomous attachment of non-cooperative targets in space. Through the guidance law for autonomous attachment of non-cooperative targets in space, the detector system state converges to the sliding surface in a fixed time and the detector moves along the sliding surface. In turn, the detector moves along the geometric convex trajectory to approach the non-cooperative target in space, which can reduce the probability of the detector colliding with space obstacles and improve the safety and robustness of the detector in space.

[0047] Differentiate formula (12)

[0048]

[0049] Substituting formula (1) into formula (17), we get

[0050]

[0051] The guidance law for autonomous attachment of a non-cooperative target convex trajectory in the design space is a.

[0052]

[0053] In the formula: operators This represents the element-wise multiplication of matrices, sgn(s) = [sgn(s)] x ),sgn(s y ),sgn(s z )] T sgn(·) is the sign function. |s0|=[|s x0 |,|s y0 |,|s z0 |] T The subscript 0 indicates the state of the detector system at time t=0, and that it exists.

[0054]

[0055] At this time, the detector system will converge to the curvature sliding surface s in a three-dimensional convex trajectory state at time t1, and maintain the convex trajectory state at t1. f Achieve precise attachment at all times.

[0056] Considering the frequent chattering problem in the control force output caused by the sign function sgn(·) in the sliding mode guidance method, the saturation function sat(·) is used instead of sgn(·), that is...

[0057]

[0058] Where Δ is a set positive threshold, at which point the guidance law shown in formula (19) is transformed into

[0059]

[0060] When there are deviations in the initial state of the detector and interference in the dynamic environment, the resistance to deviations in the initial state of the detector and interference in the dynamic environment is improved by efficiently switching the saturation function term sat(s) in the guidance law of autonomous attachment of non-cooperative targets in space. This improves the robustness of the detector during the attachment process.

[0061] The detector's guidance laws on the x, y, and z axes are respectively

[0062]

[0063]

[0064]

[0065] Step 5: Using the guidance law for autonomous attachment of non-cooperative targets in space obtained in Step 4, guidance for attachment of non-cooperative targets in space is performed in the form of x, y, and z axis components. This reduces the risk of collision with space obstacles, ensures that the detector completes accurate attachment in a convex trajectory state at a preset time, and improves the attachment safety of the detector.

[0066] Beneficial effects:

[0067] 1. The space non-cooperative target autonomous attachment convex trajectory guidance method disclosed in this invention, based on basic curvature guidance, performs equivalent transformation and relaxation of the three-dimensional convex trajectory constraint to construct a curvature sliding surface that satisfies the three-dimensional convex trajectory constraint. This ensures that when the detector system state is located on the sliding surface, the detector moves along the geometric convex trajectory. Based on this, an analytical form of the space non-cooperative target autonomous attachment convex trajectory guidance law is designed. This law enables the detector system state to converge to the sliding surface within a finite time and move along the sliding surface, maintaining the convex trajectory state and achieving precise attachment at a preset time, thus providing higher security.

[0068] 2. The space non-cooperative target autonomous attachment convex trajectory guidance method disclosed in this invention improves the resistance to detector initial state deviation and dynamic environment interference by efficiently switching the sliding mode control term sat(s) in the space non-cooperative target autonomous attachment convex trajectory guidance law, thereby improving the robustness of the detector attachment process when there is a deviation in the initial state of the detector and interference in the dynamic environment. Attached Figure Description

[0069] Figure 1 This is a schematic diagram of the process of the space non-cooperative target autonomous attachment convex trajectory guidance method of the present invention.

[0070] Figure 2 It is a dynamic vertical plane coordinate system X D OZ D Schematic diagram.

[0071] Figure 3 shows the simulation analysis results of the autonomous attachment convex trajectory guidance method for non-cooperative targets in space under conditions without initial state errors and external interference. Figure (a) shows the three-dimensional attachment trajectory of the detector, Figure (b) shows the attachment trajectory of the detector in the XOZ plane, Figure (c) shows the three-axis position curve of the detector, Figure (d) shows the three-axis velocity variation curve of the detector, Figure (e) shows the three-axis acceleration variation curve of the detector, and Figure (f) shows the three-axis sliding surface variation curve of the detector.

[0072] Figure 4 shows the results of 500 Monte Carlo simulations of the autonomous attachment convex trajectory guidance method for non-cooperative targets in space under conditions of initial state error and external interference. Figure (a) shows the attachment error in the XOY plane, Figure (b) shows the magnitude of the detector attachment velocity, and Figure (c) shows the three-dimensional attachment trajectory of the detector. Detailed Implementation

[0073] To better illustrate the purpose and advantages of the present invention, the invention will be further described below in conjunction with the accompanying drawings and examples.

[0074] Example 1:

[0075] To verify the feasibility of this invention, the asteroid 2063 Bacchus was used as the target celestial body for attachment and obstacle avoidance control. A polyhedral model was used to establish the gravitational field of the asteroid. The range [130, -210, 100] was selected as the fixed-axis coordinates of the asteroid. T m represents the target attachment point. A fixed Cartesian coordinate system O-XYZ is established on the planetary surface with the target attachment point as the origin O. In this coordinate system, the initial position of the probe is [-2000, 1000, 15000]. T m, the target attachment point is [0,0,0] T m, initial velocity [20, -40, -30] T m / s, target termination velocity is [0,0,0] T m / s, initial mass 1400 kg, engine specific impulse 298 s, guidance system simulation parameters Λ=diag(3,1.5), Δ=0.001, t1=20 s, t f =80s.

[0076] like Figure 1 As shown in the figure, the specific implementation steps of the space non-cooperative target autonomous attachment convex trajectory guidance method disclosed in this embodiment are as follows:

[0077] Step 1: Establish a fixed rectangular coordinate system on the surface of the non-cooperative target in space, and establish the detector dynamics equations and three-dimensional convex trajectory constraints in this coordinate system.

[0078] A rectangular coordinate system O-XYZ is established on the surface of the non-cooperative target in space with the target attachment point as the origin O. The Z-axis is perpendicular to the local ground plane at the location of the attachment point, and its positive direction points to the outside of the surface of the non-cooperative target in space. The X-axis is in the local plane at the location of the attachment point and coincides with the cross product vector of the positive direction of the Z-axis and the rotation direction of the non-cooperative target in space. The Y-axis, together with the X-axis and Z-axis, forms a right-handed coordinate system.

[0079] When the probe moves on the surface fixed system, it is mainly subject to the control force generated by the engine and the space gravity.

[0080] The dynamic equation of the detector system is as follows

[0081]

[0082] Where r = [x, y, z] T and v = [v x ,v y ,v z ] T Let T represent the position and velocity of the detector under surface rigidity, respectively, where T = [T x ,T y ,T z ] T and a=[a x ,a y ,a z ] T Let g and m represent the triaxial components of the detector's control force and control acceleration in the surface-fixed system, respectively; g is the gravitational force acting on the detector; m is the mass of the detector; and I is the mass of the detector. sp G represents the engine's specific impulse. e This is the gravitational acceleration at sea level on Earth.

[0083] When a probe moves along a geometrically convex trajectory towards a non-cooperative target in space, the probability of collision with space obstacles can be reduced, thus improving the probe's safety in space. In three-dimensional space, the geometric constraints of the convex trajectory are...

[0084]

[0085] When the initial state of the detector does not satisfy the three-dimensional convex trajectory constraint shown in equation (27), the detector state is quickly transformed into a convex trajectory state by constructing a curvature sliding mode feedback guidance law in the subsequent step 4, and the convex trajectory state is maintained until the target attachment point is reached.

[0086] Step 2: Establish a dynamic vertical plane coordinate system, perform equivalent transformation on the x-axis and y-axis coordinate information, and then relax the constraints of the three-dimensional convex trajectory to transform the original three-dimensional convex trajectory inequality constraints into equality constraints containing curvature relaxation terms, which facilitates the design of the curvature sliding surface in Step 3.

[0087] Define a dynamic vertical plane coordinate system X with a fixed origin and attachment points. D OZ D Z D The X axis is consistent with the Z axis, and the X axis is consistent with the Z axis. D Axis and vector [x,y,0] T Align it and point it in the positive x-axis direction, using X D OZ D The coordinate system performs an equivalent transformation of the x-axis and y-axis information.

[0088] definition vD :=dx D / dt and Equation (27) is converted to

[0089]

[0090] Detector in X D The position component of the axis x D and velocity component v D The expressions are respectively

[0091]

[0092]

[0093] After equivalent transformation, the detector's attachment trajectory in three-dimensional space is convex, which is equivalent to the trajectory in X. D OZ D The curvature in the plane is negative. Relaxing the inequality constraints on equation (28), when x... D When <0, and the attachment trajectory is convex, v satisfies D >0; when x D When >0, and the attachment trajectory is convex, v satisfies D <0, equation (28) is transformed into

[0094]

[0095] Relaxing the constraints of equation (31), we define φ = [φ D ,φ *T ] T =[φ D ,φ x ,φ y ,φ z ] T Let be the curvature relaxation term,

[0096]

[0097] When φ D >φ z When >0, geometric constraints of three-dimensional convex trajectory exist

[0098]

[0099] The geometric convex trajectory constraint shown in equation (28) is satisfied.

[0100] Step 3: Transform the equality constraints containing curvature relaxation terms in Step 2 into a curvature sliding surface form. The curvature sliding surface ensures the detector satisfies the geometric convex trajectory constraints in three-dimensional space, and that the detector's position and velocity are within the range of t... f It converges to 0 at every moment.

[0101] Define s = [s x ,s y ,s z ] T and Λ=diag(λ D ,λ D ,λ z ), and design the following curvature sliding surface.

[0102]

[0103] Let λ D >λ z When >0, and the detector system state is located on the sliding surface (s=0), the curvature relaxation term φ = [φ D ,φ z ] T satisfy

[0104]

[0105]

[0106] Satisfy the geometric convex trajectory constraints in three-dimensional space to ensure that the detector is in X D OZ D The curvature in the plane is negative. This is due to the curvature relaxation term φ. * The existence of singular values ​​at x, y, z = 0 transforms the sliding surface into an equivalent form.

[0107]

[0108] When s = 0, equation (37) is rewritten as follows:

[0109]

[0110] When using the differential form, equation (38) is transformed into

[0111]

[0112] Integrating equation (39), we get

[0113]

[0114] in Let r be the initial value of the detector system when s = 0. Differentiating equation (40) yields...

[0115]

[0116] Where I is the identity matrix. Combining equations (40)-(41), we get that as long as λ D >λ z>1, the detector will be in X D OZ D The curvature remains negative in the plane, and the position and velocity are constant at t. f It converges to 0 at every moment.

[0117] Step 4: Using the sliding surface designed in Step 3, establish a guidance law for autonomous attachment of non-cooperative targets in space. Through the guidance law for autonomous attachment of non-cooperative targets in space, the detector system state converges to the sliding surface in a fixed time and the detector moves along the sliding surface. In turn, the detector moves along the geometric convex trajectory to approach the non-cooperative target in space, which can reduce the probability of the detector colliding with space obstacles and improve the safety and robustness of the detector in space.

[0118] Differentiate formula (37)

[0119]

[0120] Substituting formula (26) into formula (42), we get

[0121]

[0122] The guidance law for autonomous attachment of a non-cooperative target convex trajectory in the design space is a.

[0123]

[0124] In the formula: operators This represents the element-wise multiplication of matrices, sgn(s) = [sgn(s)] x ),sgn(s y ),sgn(s z )] T sgn(·) is the sign function. |s0|=[|s x0 |,|s y0 |,|s z0 |] T The subscript 0 indicates the state of the detector system at time t=0, and that it exists.

[0125]

[0126] At this time, the detector system will converge to the curvature sliding surface s in a three-dimensional convex trajectory state at time t1, and maintain the convex trajectory state at t1. f Achieve precise attachment at all times.

[0127] Considering the frequent chattering problem in the control force output caused by the sign function sgn(·) in the sliding mode guidance method, the saturation function sat(·) is used instead of sgn(·), that is...

[0128]

[0129] Where Δ is a set positive threshold, at which point the guidance law shown in formula (19) is transformed into

[0130]

[0131] When there are deviations in the initial state of the detector and interference in the dynamic environment, the resistance to deviations in the initial state of the detector and interference in the dynamic environment is improved by efficiently switching the saturation function term sat(s) in the guidance law of autonomous attachment of non-cooperative targets in space. This improves the robustness of the detector during the attachment process.

[0132] The detector's guidance laws on the x, y, and z axes are respectively

[0133]

[0134]

[0135]

[0136] Step 5: Using the guidance law for autonomous attachment of non-cooperative targets in space obtained in Step 4, guidance for attachment of non-cooperative targets in space is performed in the form of x, y, and z axis components. This reduces the risk of collision with space obstacles, ensures that the detector completes accurate attachment in a convex trajectory state at a preset time, and improves the attachment safety of the detector.

[0137] Given initial and terminal conditions, the detector is guided by the space non-cooperative target autonomous attachment convex trajectory guidance method. The final simulation results are shown in Figure 3, which show that the detector can maintain the convex trajectory for a preset time to achieve precise attachment and successfully avoid obstacles.

[0138] To verify the robustness of the proposed guidance algorithm to external environmental disturbances and initial state deviations, 500 Monte Carlo simulations were conducted using a space non-cooperative target autonomous attachment convex trajectory guidance method. The average acceleration of the detector under external disturbances along its three axes was 0.1 m / s². 2 The standard deviation is 0.02 m / s. 2 The initial state is shown in Table 1.

[0139] Table 1 Initial values ​​for Monte Carlo simulation

[0140]

[0141] The final simulation results are shown in Figure 4, which demonstrate that the space non-cooperative target autonomous attachment convex trajectory guidance method can achieve precise attachment even when there are deviations in the initial state of the detector and interference in the dynamic environment, and has good accuracy and strong robustness.

[0142] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for autonomous attachment of convex trajectories to non-cooperative targets in space, characterized in that: Includes the following steps, Step 1: Establish a fixed rectangular coordinate system on the surface of a non-cooperative target in space, and establish the detector dynamics equations and three-dimensional convex trajectory constraints in this coordinate system; Step 2: Establish a dynamic vertical plane coordinate system, perform equivalent transformation on the x-axis and y-axis coordinate information, and then relax the constraints on the three-dimensional convex trajectory to transform the original three-dimensional convex trajectory inequality constraints into equality constraints containing curvature relaxation terms. Step 3: Transform the equality constraints containing curvature relaxation terms in Step 2 into a curvature sliding surface form; use the curvature sliding surface to make the detector satisfy the geometric convex trajectory constraints in three-dimensional space, and make the detector's position and velocity within t f It converges to 0 at every moment; Step 4: Use the sliding surface designed in Step 3 to establish a guidance law for autonomous attachment of non-cooperative targets in space. Through the guidance law for autonomous attachment of non-cooperative targets in space, the detector system state converges to the sliding surface in a fixed time and the detector moves along the sliding surface, thereby moving the detector along the geometric convex trajectory to approach the non-cooperative target in space. Step 5: Using the guidance law for autonomous attachment of non-cooperative targets in space obtained in Step 4, guidance for attachment of non-cooperative targets in space is performed in the form of x, y, and z axis components. This reduces the risk of collision with space obstacles and ensures that the detector completes precise attachment in a convex trajectory state at a preset time.

2. The space non-cooperative target autonomous attachment convex trajectory guidance method as described in claim 1, characterized in that: Step 1 is implemented as follows: A rectangular coordinate system O-XYZ is established on the surface of the non-cooperative target in space with the target attachment point as the origin O. The Z-axis is perpendicular to the local ground plane at the location of the attachment point, and its positive direction points to the outside of the surface of the non-cooperative target in space. The X-axis is in the local plane at the location of the attachment point and coincides with the cross product vector of the positive direction of the Z-axis and the rotation direction of the non-cooperative target in space. The Y-axis, together with the X-axis and Z-axis, forms a right-handed coordinate system. When the probe moves on the surface-fixed system, it is mainly subjected to the control force generated by the engine and the gravitational force of space; the dynamic equation of the probe system is: Where r = [x, y, z] T and v = [v x ,v y ,v z ] T Let T represent the position and velocity of the detector under surface-fixed conditions, respectively. x ,T y ,T z ] T and a=[a x ,a y ,a z ] T Let g and m represent the triaxial components of the detector's control force and control acceleration in the surface-fixed system, respectively; g is the gravitational force acting on the detector; m is the mass of the detector; and I is the mass of the detector. sp G represents the engine's specific impulse. e This represents the gravitational acceleration at sea level. When a detector moves along a geometrically convex trajectory towards a non-cooperative target in space, the probability of collision with space obstacles can be reduced, thus improving the detector's safety in space. In three-dimensional space, the geometric constraints of the convex trajectory are... When the initial state of the detector does not satisfy the three-dimensional convex trajectory constraint shown in equation (2), the detector state is quickly transformed into a convex trajectory state by constructing a curvature sliding mode feedback guidance law in the subsequent step 4, and the convex trajectory state is maintained until the target attachment point is reached.

3. The space non-cooperative target autonomous attachment convex trajectory guidance method as described in claim 2, characterized in that: Step 2 is implemented as follows: Define a dynamic vertical plane coordinate system X with a fixed origin and attachment points. D OZ D Z D The X axis is consistent with the Z axis. D Axis and vector [x,y,0] T Align it and point it in the positive x-axis direction, using X D OZ D The coordinate system performs an equivalent transformation on the x-axis and y-axis information; definition v D :=dx D / dt and Equation (2) is converted to Detector in X D The position component of the axis x D and velocity component v D The expressions are respectively After equivalent transformation, the detector's attachment trajectory in three-dimensional space is convex, which is equivalent to the trajectory in X. D OZ D The curvature in the plane is negative; inequality constraint relaxation is applied to equation (3), when x... D When <0, and the attachment trajectory is convex, v satisfies D >0; when x D When >0, and the attachment trajectory is convex, v satisfies D <0, equation (3) is transformed into Relaxing the constraints of equation (6), we define φ = [φ D ,φ *T ] T =[φ D ,φ x ,φ y ,φ z ] T Let be the curvature relaxation term, When φ D >φ z When >0, geometric constraints of three-dimensional convex trajectory exist The geometric convex trajectory constraint shown in equation (3) is satisfied.

4. The space non-cooperative target autonomous attachment convex trajectory guidance method as described in claim 3, characterized in that: Step 3 is implemented as follows: Define s = [s x ,s y ,s z ] T and Λ=diag(λ D ,λ D ,λ z And design the following curvature sliding surface. Let λ D >λ z When >0, and the detector system state is located on the sliding surface, the curvature relaxation term φ = [φ D ,φ z ] T satisfy Satisfying the geometric convex trajectory constraints in three-dimensional space, ensuring the detector in X D OZ D The curvature in the plane is negative; due to the curvature relaxation term φ * The existence of singular values ​​at x, y, z = 0 transforms the sliding surface into an equivalent form. When s = 0, equation (12) is rewritten as follows: When using the differential form, equation (13) is transformed into Integrating equation (14), we get in Let r be the initial value of the detector system when s = 0; taking the derivative of equation (15) gives... Where I is the identity matrix; combining equations (15)-(16), we get that as long as λ D >λ z >1, the detector will be in X D OZ D The curvature remains negative in the plane, and the position and velocity are constant at t. f It converges to 0 at every moment.

5. The space non-cooperative target autonomous attachment convex trajectory guidance method as described in claim 4, characterized in that: Step 4 is implemented as follows: Differentiate formula (12) Substituting formula (1) into formula (17), we get The guidance law for autonomous attachment of a non-cooperative target convex trajectory in the design space is a. In the formula: operators This represents the element-wise multiplication of matrices, sgn(s) = [sgn(s)] x ),sgn(s y ),sgn(s z )] T sgn(·) is the sign function; |s0|=[|s x0 |,|s y0 |,|s z0 |] T The subscript 0 indicates the state of the detector system at time t=0, and that it exists. At this time, the detector system will converge to the curvature sliding surface s in a three-dimensional convex trajectory state at time t1, and maintain the convex trajectory state at t1. f Achieve precise attachment at all times; Considering the frequent chattering problem in the control force output caused by the sign function sgn(·) in the sliding mode guidance method, the saturation function sat(·) is used instead of sgn(·), that is... Where Δ is a set positive threshold, at which point the guidance law shown in formula (19) is transformed into When there are deviations in the initial state of the detector and interference in the dynamic environment, the resistance to deviations in the initial state of the detector and interference in the dynamic environment is improved by efficiently switching the saturation function term sat(s) in the guidance law of autonomous attachment of non-cooperative space targets, thereby improving the robustness of the detector during the attachment process. The detector's guidance laws on the x, y, and z axes are respectively

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