An online spacecraft trajectory planning method based on inverse dynamics motion camouflage

Abstract

The present invention discloses a spacecraft trajectory online planning method based on inverse dynamics motion camouflage, which relates to the field of spacecraft technology, including: constructing a spacecraft trajectory planning model based on a spacecraft orbital dynamics model, control capability constraints, boundary condition constraints and performance indicators corresponding to a spacecraft trajectory planning process; constructing and solving a discrete form of a spacecraft trajectory planning model using an inverse dynamics algorithm, and obtaining reference state variables and reference control variables of the spacecraft between a starting position and a terminal position; establishing a spacecraft trajectory online planning model based on the reference state variables and reference control variables using a motion camouflage algorithm; solving the spacecraft trajectory online planning model using a sequential quadratic programming algorithm and a rolling time domain control algorithm, and obtaining state variables and control variables of the spacecraft between a starting position and a terminal position. The present invention can realize online spacecraft trajectory planning, reduce the dimension of the planning problem, and improve the solution efficiency and solution accuracy.

Description

Technical Field

[0001] The present invention relates to the field of spacecraft technology, and in particular to an online spacecraft trajectory planning method based on inverse dynamics motion camouflage. Background Art

[0002] Online trajectory planning for spacecraft can adjust the flight trajectory according to real-time conditions to ensure that the spacecraft can complete the mission according to the predetermined goals. In a complex space environment, spacecraft may face various unknown factors and potential risks, such as space debris and gravitational disturbances of celestial bodies. Through online trajectory planning, spacecraft can flexibly respond to these challenges, reduce the risk of mission failure, and ensure flight safety. Online trajectory planning for spacecraft also plays a key role in supporting complex missions and emergency responses. For example, when performing complex missions such as deep space exploration and interstellar travel, spacecraft need to face a changing space environment and complex mission requirements. Through online trajectory planning, spacecraft can adjust flight strategies in real time to respond to various emergencies and ensure the smooth progress of the mission. At the same time, when responding to space accidents or emergencies, such as spacecraft failures and collision warnings, online trajectory planning can also provide timely emergency response plans to ensure the safety of spacecraft.

[0003] Spacecraft online trajectory planning is essentially a complex nonlinear optimization problem with multiple constraints. Currently, direct and indirect methods are usually used to obtain numerical solutions. However, the direct method is prone to falling into local optimal solutions, slow convergence speed, and initial value guessing. The indirect method has shortcomings such as complex solution process, small convergence domain, and difficulty in constraint processing. The above direct and indirect methods are both poor in practical application to spacecraft trajectory online planning. Summary of the invention

[0004] In order to solve some or all of the technical problems existing in the above-mentioned prior art, the present invention provides an online spacecraft trajectory planning method based on inverse dynamics motion camouflage.

[0005] The technical solution of the present invention is as follows:

[0006] A spacecraft trajectory online planning method based on inverse dynamics motion camouflage is provided, including:

[0007] Build spacecraft orbital dynamics models;

[0008] Construct control capability constraints, boundary condition constraints and performance indicators corresponding to the spacecraft trajectory planning process;

[0009] Based on the spacecraft orbital dynamics model, as well as the control capability constraints, boundary condition constraints and performance indicators corresponding to the spacecraft trajectory planning process, a general form of spacecraft trajectory planning model is constructed;

[0010] Based on the general form of the spacecraft trajectory planning model, the inverse dynamics algorithm is used to construct and solve the discrete form of the spacecraft trajectory planning model to obtain the reference state variables and reference control variables of the spacecraft between the starting position and the terminal position;

[0011] Based on the reference state variables and reference control variables of the spacecraft between the starting position and the terminal position, the spacecraft trajectory online planning model is established using the motion camouflage algorithm.

[0012] The sequential quadratic programming algorithm and the receding horizon control algorithm are used to solve the online planning model of the spacecraft trajectory and obtain the state variables and control variables of the spacecraft between the starting position and the terminal position.

[0013] In some optional embodiments, the spacecraft orbital dynamics model is expressed as:

[0014] ;

[0015] in, , and They represent the position vector, velocity vector and unit mass control acceleration vector of the spacecraft in the geocentric inertial system, respectively. , , , They represent the position of the spacecraft in the Earth-centered inertial system. x axis, y Axis and z Component below the axis, subscript Indicates the corresponding physical quantity in the geocentric inertial system x axis, y Axis and z The weight below the axis, represents the gravitational constant of the central celestial body around which the spacecraft orbits, , Respectively , First derivative with respect to time.

[0016] In some optional implementations, the control capability constraint is expressed as:

[0017] ;

[0018] in, is the maximum unit mass control acceleration that the spacecraft engine can provide, Represents the 2-norm of a vector.

[0019] In some optional implementations, the boundary condition constraint is expressed as:

[0020] ;

[0021] in, , and represent the starting time, starting position and starting speed of the given spacecraft maneuver respectively, and They represent the spacecraft at the start time The position and velocity of represents the given spacecraft maneuvering terminal position, Indicates that the spacecraft is at terminal time location, represents the given spacecraft maneuvering terminal velocity, Indicates that the spacecraft is at terminal time speed.

[0022] In some optional embodiments, the performance indicator includes the shortest time or the minimum speed increment;

[0023] The shortest performance index is expressed as:

[0024] ;

[0025] The minimum speed increment performance index is expressed as:

[0026] ;

[0027] in, , They represent the shortest time performance function and the minimum speed increment performance function respectively. Represents a time variable.

[0028] In some optional embodiments, the general form of the spacecraft trajectory planning model is expressed as:

[0029] .

[0030] In some optional embodiments, the inverse dynamics algorithm includes: Bezier curve method.

[0031] In some optional implementations, when the inverse dynamics algorithm is the Bezier curve method, the discrete form of the spacecraft trajectory planning model is expressed as:

[0032] ;

[0033] in, is the normalized time scale, represents the state variable Bessel basis function, Indicates the position of the Bezier curve control point. and Represents the position vector about The first and second derivatives of and They represent the state variable Bessel basis functions about The first and second derivatives of Indicates the number of matching points of the selected Bezier curve, represents the order of the Bezier curve, Indicates Points, suffix Indicates that the corresponding physical quantity is The value of the moment.

[0034] In some optional implementations, the spacecraft trajectory online planning model is expressed as:

[0035] ;

[0036] in, represents the position ratio, and Respectively The first and second derivatives with respect to time, They represent the optimized position of the spacecraft in the Earth-centered inertial system. x axis, y Axis and z The weight below the axis, represents the distance from the optimized position of the spacecraft to the center of the earth, , Respectively The second derivative with respect to time is They represent the reference position of the spacecraft in the Earth-centered inertial system. x axis, y Axis and z The weight below the axis, They represent the relative position between the preset reference point and the spacecraft reference position in the Earth-centered inertial system. x axis, y Axis and z The weight below the axis, Respectively The first derivative with respect to time is Respectively The second derivative with respect to time is Indicates the start time The position ratio, Indicates terminal time The position ratio, and Respectively and First derivative with respect to time.

[0037] In some optional implementations, the use of a sequential quadratic programming algorithm and a receding horizon control algorithm to solve the spacecraft trajectory online planning model and obtain state variables and control variables of the spacecraft between the starting position and the terminal position includes the following steps:

[0038] Step 601, determine the initial state of the spacecraft maneuver , Terminal state of spacecraft maneuver , the start time of the spacecraft maneuver , the maximum unit mass control acceleration of the spacecraft , set the step time step of rolling optimization , determine the reference state variables and reference control variables of the spacecraft between the starting position and the terminal position;

[0039] Step 602, using a sequential quadratic programming algorithm to solve the spacecraft trajectory online planning model, obtain The state variables and control variables of the spacecraft at time;

[0040] Step 603: The state variables of the spacecraft at time t are taken as the initial state of the spacecraft maneuver, and moment as the starting moment;

[0041] Step 604, looping through steps 602-603 until the spacecraft reaches a set terminal state, and obtaining the state variables and control variables of the spacecraft between the starting position and the terminal position.

[0042] The main advantages of the technical solution of the present invention are as follows:

[0043] The method for online planning of spacecraft trajectory based on inverse dynamics motion camouflage of the present invention solves the spacecraft trajectory planning model based on the inverse dynamics algorithm, uses the spacecraft trajectory obtained by solving the inverse dynamics algorithm as the reference trajectory, establishes the spacecraft trajectory online planning model in combination with the motion camouflage algorithm, and uses the rolling time domain control algorithm to optimize the solution of the spacecraft trajectory online planning model. It can realize the online planning of spacecraft trajectory, reduce the dimension of the spacecraft trajectory online planning problem, improve the solution efficiency, reduce the solution calculation amount and time consumption, and can significantly improve the accuracy and reliability of the trajectory online planning results. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The drawings described herein are used to provide a further understanding of the embodiments of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0045] Figure 1 A flowchart of a method for online spacecraft trajectory planning based on inverse dynamics motion camouflage provided by an embodiment of the present invention;

[0046] Figure 2 A schematic diagram of the principle of a motion camouflage algorithm in an online spacecraft trajectory planning method based on inverse dynamics motion camouflage provided by an embodiment of the present invention;

[0047] Figure 3 A schematic diagram of the principles of a method for online spacecraft trajectory planning based on inverse dynamics motion camouflage provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0049] The technical solution provided by the embodiments of the present invention is described in detail below with reference to the accompanying drawings.

[0050] See also Figure 1 The embodiment of the present invention provides a method for online spacecraft trajectory planning based on inverse dynamics motion camouflage, the method comprising the following steps 1 to 6:

[0051] Step 1: Establish a spacecraft orbital dynamics model.

[0052] Specifically, since the spacecraft needs to satisfy the spacecraft orbital dynamics constraints when performing trajectory planning, a corresponding spacecraft orbital dynamics model is established based on the spacecraft orbital dynamics constraints.

[0053] In the embodiment of the present invention, the established spacecraft orbital dynamics model is expressed as:

[0054] ;

[0055] in, , and They represent the position vector, velocity vector and unit mass control acceleration vector of the spacecraft in the geocentric inertial system, respectively. , , , They represent the position of the spacecraft in the Earth-centered inertial system. x axis, y Axis and z Component below the axis, subscript Indicates the corresponding physical quantity in the geocentric inertial system x axis, y Axis and z The weight below the axis, represents the gravitational constant of the central celestial body around which the spacecraft orbits, , Respectively , First derivative with respect to time.

[0056] Accordingly, in the embodiment of the present invention, the state variable of the spacecraft is expressed as , the control variable of the spacecraft is the unit mass control acceleration vector, expressed as , represents the control variable.

[0057] Step 2: Construct the control capability constraints, boundary condition constraints and performance indicators corresponding to the spacecraft trajectory planning process.

[0058] In the embodiment of the present invention, the control capability constraint corresponding to the spacecraft trajectory planning process is expressed as:

[0059] ;

[0060] in, is the maximum unit mass control acceleration that the spacecraft engine can provide, Represents the 2-norm of a vector.

[0061] Furthermore, in the embodiment of the present invention, during the spacecraft trajectory planning process, it is only necessary to control the spacecraft to reach a given terminal position and terminal velocity, and the terminal time can be optimized and adjusted according to the optimization target. To this end, in the embodiment of the present invention, the boundary condition constraints corresponding to the spacecraft trajectory planning process include: starting time constraint, starting position constraint, starting time velocity constraint, terminal position constraint and terminal velocity constraint.

[0062] Specifically, the boundary condition constraints corresponding to the spacecraft trajectory planning process are expressed as:

[0063] ;

[0064] in, , and represent the starting time, starting position and starting speed of the given spacecraft maneuver respectively, and They represent the spacecraft at the start time The position and velocity of represents the given spacecraft maneuvering terminal position, Indicates that the spacecraft is at terminal time location, represents the given spacecraft maneuvering terminal velocity, Indicates that the spacecraft is at terminal time speed.

[0065] Among them, the starting time, starting position, starting speed, terminal position and terminal speed of the spacecraft maneuver are given according to actual conditions.

[0066] Furthermore, in an embodiment of the present invention, the performance indicator includes the shortest time or the minimum speed increment.

[0067] Specifically, the shortest time performance index is expressed as:

[0068] ;

[0069] The minimum speed increment performance index is expressed as:

[0070] ;

[0071] in, , They represent the shortest time performance function and the minimum speed increment performance function respectively. Represents a time variable.

[0072] In the actual spacecraft trajectory planning process, the performance indicator can select the shortest time or minimum velocity increment according to actual needs.

[0073] Step 3: construct a general form of spacecraft trajectory planning model based on the spacecraft orbital dynamics model, as well as the control capability constraints, boundary condition constraints and performance indicators corresponding to the spacecraft trajectory planning process.

[0074] Specifically, in an embodiment of the present invention, based on the above-constructed spacecraft orbital dynamics model, and the control capability constraints, boundary condition constraints and performance indicators corresponding to the above-set spacecraft trajectory planning process, the general form of the constructed spacecraft trajectory planning model is expressed as:

[0075] .

[0076] Step 4: Based on the general form of the spacecraft trajectory planning model, the inverse dynamics algorithm is used to construct and solve the discrete form of the spacecraft trajectory planning model to obtain the reference state variables and reference control variables of the spacecraft between the starting position and the terminal position.

[0077] In the embodiment of the present invention, the inverse dynamics algorithm includes: Bezier curve method.

[0078] The Bezier curve is a parametric mathematical curve defined by control points. The Bezier curve has the unique ability to generate continuous and smooth trajectories. Its derivatives of all orders exist, which means that the velocity, acceleration and other dynamic characteristics of the trajectory can be directly obtained by differentiation. This feature can greatly facilitate the real-time adjustment of the trajectory. A notable feature of the Bezier curve is that its shape is always within the convex hull formed by the control points, which makes it easier to handle obstacle constraints during path planning, ensuring that the generated trajectory will not collide with obstacles in the environment, and by adjusting the position of the control points, the shape of the Bezier curve can be flexibly changed to meet different trajectory optimization requirements.

[0079] In the embodiment of the present invention, when solving the spacecraft trajectory planning model using the Bezier curve method in the inverse dynamics algorithm, the position parameters, velocity parameters and acceleration parameters of the spacecraft are converted into algebraic equations respectively.

[0080] Specifically, the algebraic equation corresponding to the position parameters of the spacecraft can be expressed as:

[0081] ;

[0082] in, is the normalized time scale, , represents the time variable, Indicates the terminal time, express The position vector of the spacecraft in the geocentric inertial system at time , represents the order of the Bezier curve, Indicates the position of the Bezier curve control point. represents the state variable Bessel basis functions.

[0083] Among them, the state variable Bessel basis function Defined as:

[0084] .

[0085] Furthermore, since the velocity and acceleration of the spacecraft can be expressed by the first-order derivative and the second-order derivative of the position with respect to time, in the embodiment of the present invention, the algebraic equation corresponding to the velocity parameter of the spacecraft can be expressed as:

[0086] ;

[0087] The algebraic equation corresponding to the acceleration parameters of the spacecraft can be expressed as:

[0088] ;

[0089] in, and Represents the position vector about The first and second derivatives of and They represent the state variable Bessel basis functions about The first and second derivatives of .

[0090] Based on the above Definition, and They are defined as:

[0091] ;

[0092] .

[0093] Furthermore, in an embodiment of the present invention, a discrete form of a spacecraft trajectory planning model is constructed based on the above-constructed general form of the spacecraft trajectory planning model and the above-set algebraic equations.

[0094] Specifically, based on the general form of the spacecraft trajectory planning model constructed above and the algebraic equations set above, the discrete form of the spacecraft trajectory planning model constructed is expressed as:

[0095] ;

[0096] in, Indicates the number of matching points of the selected Bezier curve, represents the order of the Bezier curve, Indicates Points, suffix Indicates that the corresponding physical quantity is The value of the moment.

[0097] Among them, the number of points and the order of the Bezier curve are selected according to actual needs.

[0098] In an embodiment of the present invention, after constructing a discrete form of the spacecraft trajectory planning model based on the general form of the spacecraft trajectory planning model constructed above and the algebraic equations set above, the discrete form of the spacecraft trajectory planning model is solved using the existing sequential quadratic programming algorithm to determine the terminal moment, the control point position of the Bezier curve and the reference trajectory of the spacecraft, and then obtain the reference state variables and reference control variables of the spacecraft between the starting position and the terminal position.

[0099] Step 5: Based on the reference state variables and reference control variables of the spacecraft between the starting position and the terminal position, a motion camouflage algorithm is used to establish an online planning model for the spacecraft trajectory.

[0100] refer to Figure 2 In the embodiment of the present invention, for the spacecraft trajectory online planning process, the basic equation of motion camouflage can be expressed as:

[0101] ;

[0102] in, represents the optimized position of the spacecraft in the geocentric inertial system, , They represent the optimized position of the spacecraft in the Earth-centered inertial system. x axis, y Axis and z The weight below the axis, represents the reference position of the spacecraft in the Earth-centered inertial system, , They represent the reference position of the spacecraft in the Earth-centered inertial system. x axis, y Axis and z The weight below the axis, Indicates the relative position between the preset reference point and the spacecraft reference position. , Respectively represent the relative position in the Earth-centered inertial system x axis, y Axis and z The weight below the axis, Indicates the position of the preset reference point in the geocentric inertial system. , Respectively represent the preset reference point position in the Earth-centered inertial system x axis, y Axis and z The weight below the axis, Represents the position ratio.

[0103] In an embodiment of the present invention, the reference point and / or position ratio may be a preset parameter, which is pre-set according to actual conditions; the reference point and / or position ratio may also be an optimization variable, which is optimized and updated based on a preset initial value during subsequent optimization solution.

[0104] Furthermore, since the velocity and acceleration of the spacecraft can be represented by the first-order derivative and the second-order derivative of the position with respect to time, in the embodiment of the present invention, the motion camouflage equation for the velocity and acceleration of the spacecraft can be obtained according to the basic equation of motion camouflage set above.

[0105] Specifically, the motion camouflage equation for the velocity and acceleration of the spacecraft can be expressed as:

[0106] ;

[0107] in, and Respectively The first and second derivatives with respect to time, and Respectively The first and second derivatives with respect to time, and Respectively The first and second derivatives with respect to time, and Respectively First and second derivatives with respect to time.

[0108] Furthermore, we select the geocentric inertial system x Unit mass control acceleration in the axis direction As a control variable, according to the above spacecraft orbital dynamics model, we can get:

[0109] ;

[0110] in, express The second derivative with respect to time is , Represents the distance from the optimized position of the spacecraft to the center of the earth.

[0111] Combined with the motion camouflage equation for the acceleration of the spacecraft obtained above, the formula It can be further expressed as:

[0112] ;

[0113] By transforming the above formula, we can get:

[0114] ;

[0115] in, express The second derivative with respect to time is express The first derivative with respect to time is express Second derivative with respect to time.

[0116] Furthermore, we select the geocentric inertial system y Unit mass control acceleration in the axis direction and the Earth-centered inertial system z Unit mass control acceleration in the axis direction As a control variable, refer to the above analysis of the geocentric inertial system. x Unit mass control acceleration in the axis direction The analysis process can be obtained:

[0117] ;

[0118] ;

[0119] in, express The second derivative with respect to time is express The first derivative with respect to time is express The second derivative with respect to time is express The second derivative with respect to time is express The first derivative with respect to time is express Second derivative with respect to time.

[0120] Furthermore, in the embodiment of the present invention, since the start time, start position, start time velocity, terminal position and terminal velocity of the spacecraft maneuver are all pre-given specific values, the above values ​​are equal in the reference trajectory and the optimized trajectory obtained by solving. Therefore, the following conditions are satisfied at the start time and the terminal time: .

[0121] Furthermore, in an embodiment of the present invention, based on the above analysis, the following spacecraft trajectory online planning model is established:

[0122] ;

[0123] in, Indicates the start time The position ratio, Indicates terminal time The position ratio, and Respectively and First derivative with respect to time.

[0124] Step 6: Use the sequential quadratic programming algorithm and the receding horizon control algorithm to solve the spacecraft trajectory online planning model and obtain the state variables and control variables of the spacecraft between the starting position and the terminal position.

[0125] refer to Figure 3 Specifically, in an embodiment of the present invention, a sequential quadratic programming algorithm and a receding horizon control algorithm are used to solve an online planning model of a spacecraft trajectory, and the state variables and control variables of the spacecraft between the starting position and the terminal position are obtained, including the following steps:

[0126] Step 601, determine the initial state of the spacecraft maneuver , Terminal state of spacecraft maneuver , the start time of the spacecraft maneuver , the maximum unit mass control acceleration of the spacecraft , set the step time step of rolling optimization Determine reference state variables and reference control variables of the spacecraft between the starting position and the terminal position;

[0127] Step 602, using a sequential quadratic programming algorithm to solve the spacecraft trajectory online planning model, obtain The state variables and control variables of the spacecraft at time;

[0128] Step 603: The state variables of the spacecraft at time t are taken as the initial state of the spacecraft maneuver, and moment as the starting moment;

[0129] Step 604, looping through steps 602-603 until the spacecraft reaches a set terminal state, and obtaining the state variables and control variables of the spacecraft between the starting position and the terminal position.

[0130] It should be noted that in step 601, the initial state of the spacecraft maneuver , Terminal state of spacecraft maneuver , the start time of the spacecraft maneuver , the maximum unit mass control acceleration of the spacecraft Set it according to the actual situation.

[0131] It should be noted that, in step 601 , the reference state variables and reference control variables of the spacecraft between the starting position and the terminal position are the reference state variables and reference control variables obtained in step 4 .

[0132] It should be noted that in the attached Figure 3 middle, and Respectively The position and velocity of the spacecraft in the Earth-centered inertial system at the time.

[0133] Further, in the embodiment of the present invention, in the above step 4 and step 6, the process principles of using the sequential quadratic programming algorithm to solve the discrete form of the spacecraft trajectory planning model and using the sequential quadratic programming algorithm to solve the spacecraft trajectory online planning model are the same, and specifically include the following steps:

[0134] Define the initial point: select an initial point as the starting point of the iteration;

[0135] Constructing augmented objective function: Using the objective function and constraints to construct augmented objective function, the constrained optimization problem is transformed into an unconstrained optimization problem;

[0136] Solve quadratic programming subproblems: In each iteration, a descent direction is determined by solving a quadratic programming subproblem;

[0137] Determine the search direction and step size: Determine the search direction and step size based on the descent direction obtained in the previous step;

[0138] Update iteration point: Update the current iteration point according to the search direction and step size;

[0139] Determine the termination condition: Check whether the termination condition is met. If so, stop the iteration; otherwise, return to the second step to continue the iteration. The termination condition may be, for example, reaching a preset number of iterations or the objective function value changing less than a preset threshold.

[0140] Output results: Output the final iteration results.

[0141] The method for online planning of spacecraft trajectory based on inverse dynamics motion camouflage provided by an embodiment of the present invention solves the spacecraft trajectory planning model based on the inverse dynamics algorithm, uses the spacecraft trajectory obtained by solving the inverse dynamics algorithm as the reference trajectory, establishes the spacecraft trajectory online planning model in combination with the motion camouflage algorithm, and uses the rolling time domain control algorithm to optimize the solution of the spacecraft trajectory online planning model. It can realize the online planning of spacecraft trajectory, reduce the dimension of the spacecraft trajectory online planning problem, improve the solution efficiency, reduce the solution calculation amount and time consumption, and can significantly improve the accuracy and reliability of the trajectory online planning results.

[0142] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spacecraft trajectory online planning method based on inverse dynamics motion camouflage, characterized in that: include: Build spacecraft orbital dynamics models; Construct control capability constraints, boundary condition constraints and performance indicators corresponding to the spacecraft trajectory planning process; Based on the spacecraft orbital dynamics model, as well as the control capability constraints, boundary condition constraints and performance indicators corresponding to the spacecraft trajectory planning process, a general form of spacecraft trajectory planning model is constructed; Based on the general form of the spacecraft trajectory planning model, the inverse dynamics algorithm is used to construct and solve the discrete form of the spacecraft trajectory planning model to obtain the reference state variables and reference control variables of the spacecraft between the starting position and the terminal position; Based on the reference state variables and reference control variables of the spacecraft between the starting position and the terminal position, the spacecraft trajectory online planning model is established using the motion camouflage algorithm. The sequential quadratic programming algorithm and the receding horizon control algorithm are used to solve the online planning model of the spacecraft trajectory and obtain the state variables and control variables of the spacecraft between the starting position and the terminal position.

2. The spacecraft trajectory online planning method based on inverse dynamics motion camouflage according to claim 1 is characterized in that: The spacecraft orbital dynamics model is expressed as: ； in, , and They represent the position vector, velocity vector and unit mass control acceleration vector of the spacecraft in the geocentric inertial system, respectively. , , , They represent the position of the spacecraft in the Earth-centered inertial system. x axis, y Axis and z Component below the axis, subscript Indicates the corresponding physical quantity in the geocentric inertial system x axis, y Axis and z The weight below the axis, represents the gravitational constant of the central celestial body around which the spacecraft orbits, , Respectively , First derivative with respect to time.

3. The spacecraft trajectory online planning method based on inverse dynamics motion camouflage according to claim 2 is characterized in that: The control capability constraint is expressed as: ； in, is the maximum unit mass control acceleration that the spacecraft engine can provide, Represents the 2-norm of a vector.

4. The spacecraft trajectory online planning method based on inverse dynamics motion camouflage according to claim 3 is characterized in that: The boundary condition constraints are expressed as: ； in, , and represent the starting time, starting position and starting speed of the given spacecraft maneuver respectively, and They represent the spacecraft at the start time The position and velocity of represents the given spacecraft maneuvering terminal position, Indicates that the spacecraft is at terminal time location, represents the given spacecraft maneuvering terminal velocity, Indicates that the spacecraft is at terminal time speed.

5. The method for online spacecraft trajectory planning based on inverse dynamics motion camouflage according to claim 4 is characterized in that: The performance indicators include the shortest time or minimum speed increment; The shortest performance index is expressed as: ； The minimum speed increment performance index is expressed as: ； in, , They represent the shortest time performance function and the minimum speed increment performance function respectively. Represents a time variable.

6. The method for online spacecraft trajectory planning based on inverse dynamics motion camouflage according to claim 5 is characterized in that: The general form of the spacecraft trajectory planning model is expressed as: 。 7. The method for online spacecraft trajectory planning based on inverse dynamics motion camouflage according to claim 6 is characterized in that: The inverse dynamics algorithm includes: Bezier curve method.

8. The method for online spacecraft trajectory planning based on inverse dynamics motion camouflage according to claim 7 is characterized in that: When the inverse dynamics algorithm is the Bezier curve method, the discrete form of the spacecraft trajectory planning model is expressed as: ； in, is the normalized time scale, represents the state variable Bessel basis function, Indicates the position of the Bezier curve control point. and Represents the position vector about The first and second derivatives of and They represent the state variable Bessel basis functions about The first and second derivatives of Indicates the number of matching points of the selected Bezier curve, represents the order of the Bezier curve, Indicates Points, suffix Indicates that the corresponding physical quantity is The value of the moment.

9. The spacecraft trajectory online planning method based on inverse dynamics motion camouflage according to claim 8 is characterized in that: The spacecraft trajectory online planning model is expressed as: ； in, represents the position ratio, and Respectively The first and second derivatives with respect to time, They represent the optimized position of the spacecraft in the Earth-centered inertial system. x axis, y Axis and z The weight below the axis, represents the distance from the optimized position of the spacecraft to the center of the earth, , Respectively The second derivative with respect to time is They represent the reference position of the spacecraft in the Earth-centered inertial system. x axis, y Axis and z The weight below the axis, They represent the relative position between the preset reference point and the spacecraft reference position in the Earth-centered inertial system. x axis, y Axis and z The weight below the axis, Respectively The first derivative with respect to time is Respectively The second derivative with respect to time is Indicates the start time The position ratio, Indicates terminal time The position ratio, and Respectively and First derivative with respect to time.

10. The method for online spacecraft trajectory planning based on inverse dynamics motion camouflage according to claim 9, characterized in that: The method of solving the spacecraft trajectory online planning model by using the sequential quadratic programming algorithm and the receding horizon control algorithm to obtain the state variables and control variables of the spacecraft between the starting position and the terminal position includes the following steps: Step 601, determine the initial state of the spacecraft maneuver , Terminal state of spacecraft maneuver , the start time of the spacecraft maneuver , the maximum unit mass control acceleration of the spacecraft , set the step time step of rolling optimization , determine the reference state variables and reference control variables of the spacecraft between the starting position and the terminal position; Step 602, using a sequential quadratic programming algorithm to solve the spacecraft trajectory online planning model, obtain The state variables and control variables of the spacecraft at the time; Step 603: The state variables of the spacecraft at time t are taken as the initial state of the spacecraft maneuver, and moment as the starting moment; Step 604, looping through steps 602-603 until the spacecraft reaches a set terminal state, and obtaining the state variables and control variables of the spacecraft between the starting position and the terminal position.

Images