An aerodynamic force modeling method for reusable rocket path planning, a storage medium and a server
By constructing a linearized aerodynamic model, the problems of large computational load and difficult optimization solutions in rocket landing path planning were solved, achieving efficient and real-time path planning and fuel-saving effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING LANDSPACETECH CO LTD
- Filing Date
- 2026-04-20
- Publication Date
- 2026-07-14
Smart Images
Figure CN122389709A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aerospace launch vehicle technology, and in particular to an aerodynamic modeling method, storage medium, and server for reusable rocket path planning. Background Technology
[0002] With the development of commercial spaceflight, vertical recovery and reuse technology for launch vehicles has become a key means to reduce the cost of space launches. During the rocket's return and landing process, especially during the flight phase within the atmosphere, the rocket is subjected to enormous aerodynamic forces (typically on the order of several to tens of tons), making the accuracy and efficiency of aerodynamic force calculations particularly important.
[0003] In existing technologies, rocket aerodynamic calculations typically rely on multidimensional aerodynamic coefficient interpolation tables (look-up tables), where these coefficients are usually nonlinear functions of Mach number, angle of attack, sideslip angle, and even rudder deflection angle. However, during online trajectory planning for the rocket's landing phase, the onboard computer needs to solve the optimal control problem within an extremely short timeframe (milliseconds). Directly using high-dimensional, nonlinear aerodynamic interpolation tables in the planning algorithm leads to the following problems:
[0004] 1. Excessive computational load: Frequent table lookups and interpolation operations consume a lot of computational resources.
[0005] 2. Difficulty in optimization: The nonlinear aerodynamic model makes the path planning problem a non-convex problem, which makes it difficult for the solution algorithm (such as sequential convex optimization, pseudospectral method, etc.) to converge or has a slow convergence speed.
[0006] 3. Limited storage space: The complete all-space aerodynamic database is large in size and occupies onboard storage resources.
[0007] Therefore, there is an urgent need for a simplified aerodynamic modeling method that can retain the main characteristics of aerodynamics, is simple in form, easy to decouple, and is suitable for rocket vertical landing conditions (usually small angle of attack and small sideslip angle) in order to improve the real-time performance and robustness of path planning. Summary of the Invention
[0008] To address the aforementioned technical problems, this invention proposes an aerodynamic modeling method, storage medium, and server for reusable rocket path planning. The aerodynamic modeling method of this invention is based on the dynamic characteristics of the rocket landing segment, and utilizes the small angle of attack assumption and velocity correlation decoupling to construct a linearized aerodynamic model.
[0009] This invention provides an aerodynamic modeling method for reusable rocket path planning, comprising at least the following steps:
[0010] Establish the landing coordinate system and the rocket body coordinate system, and set the rocket to be in the powered descent phase during the planning stage, with an angle of attack of [missing information]. and sideslip angle The value of A is limited to the range of [-A, +A], where A ranges from 5° to 10°.
[0011] Based on thrust vector Aerodynamic vector and gravity vector Establish the particle dynamics equations of the rocket in the landing coordinate system, and project them onto the landing coordinate system to form a preliminary aerodynamic model: ;
[0012] Solving the aerodynamic vector The method is as follows:
[0013] The aerodynamic coefficient data of the rocket's entire trajectory are acquired and linearized to form aerodynamic force vectors. Simplify the equations;
[0014] Obtain a standard landing reference trajectory data for the rocket, and based on the velocity profile of the standard reference trajectory, calculate the aerodynamic vector. The simplified equations are encapsulated in terms of velocity only. The product of the function term and the angle:
[0015] ;
[0016] The function was obtained by fitting offline aerodynamic data and standard ballistic data. , and ,in, , and Regarding speed A polynomial function or a one-dimensional interpolation function;
[0017] The calculated aerodynamic vector Substituting these values into the initial aerodynamic model, we obtain the final aerodynamic model for path planning:
[0018]
[0019] in, For rocket mass, It is a velocity vector. This is the transition matrix from the rocket body coordinate system to the landing coordinate system, derived from the attitude angles (roll). ,yaw , looking up )Sure; This is the thrust vector in the arrow body coordinate system; This is the gravity vector.
[0020] Furthermore, the aerodynamic coefficient data of the rocket's entire trajectory is acquired and linearized to form an aerodynamic force vector. The specific method for simplifying the equations is as follows:
[0021] Obtain aerodynamic coefficient data for the entire rocket trajectory, including , and ,in, The drag coefficient, The lift coefficient, This is the lateral force coefficient. It is the Mach number;
[0022] Linearization of aerodynamic coefficient data is performed. Linearization to ,Will Linearization to ;
[0023] Among them, the drag coefficient At small angle of attack The following can be approximated as being related only to the Mach number, i.e. ;
[0024] Simplified aerodynamic vector equations are formed:
[0025] in, Let be the derivative of the lift coefficient with respect to the angle of attack. This is the derivative of the lateral force coefficient with respect to the sideslip angle. For dynamic pressure, The characteristic area is denoted as .
[0026] Furthermore, a standard landing reference trajectory data for the rocket is obtained, and based on the velocity profile of the standard reference trajectory, the aerodynamic vector is... The simplified equations are encapsulated in terms of velocity only. The specific method for obtaining the product of the function term and the angle is as follows:
[0027] During the rocket's landing in the atmosphere, dynamic pressure The aerodynamic derivative is mainly related to velocity. (or Mach number) strongly correlated, and characteristic area The constant is used; based on this, a standard landing reference trajectory data for the rocket is obtained, and based on the velocity profile of the standard reference trajectory, the aerodynamic vector is... Packaged as speed-only The product of the function term and the angle:
[0028] .
[0029] Furthermore, the function obtained by fitting offline aerodynamic data and standard ballistic data... , and The specific method is as follows:
[0030] After obtaining a standard landing reference trajectory data for the rocket, and combining it with the drag coefficient and slope... Lift coefficient slope and lateral force coefficient slope Calculate the reference or gradient values of aerodynamic components:
[0031]
[0032]
[0033]
[0034] in, This is the reference value for resistance. For the lift gradient, For the lateral force gradient, Current speed;
[0035] With speed Establish a fitting function with the variable as the independent variable:
[0036]
[0037]
[0038]
[0039] Its fitting form can be a high-order polynomial.
[0040] Furthermore, in the path planning algorithm of the onboard computer, the final dynamic model is further simplified, specifically as follows:
[0041]
[0042] in, This is the transfer matrix from the arrow system to the landing system. For thrust amplitude, For the mass of the rocket recovery section, For gravitational acceleration; the aerodynamic vector is modeled as depending only on the current velocity. and control variables ( The analytical form of ) can be solved quickly through iteration without the need for table lookup.
[0043] Furthermore, the aerodynamic modeling method for reusable rocket path planning in this embodiment of the invention further includes: in the path planning algorithm, the final dynamic model is used as part of the equality constraint or objective function; when the rocket body coordinate system is... velocity When in a dominant position, utilize , The approximate relationship transforms aerodynamic forces into a function of velocity state variables, thereby eliminating the explicit dependence of angle control variables on aerodynamic terms and facilitating convex optimization solutions; where, In the arrow body coordinate system The speed of the direction, In the arrow body coordinate system The speed of the direction.
[0044] In any of the above embodiments, the method for obtaining the aerodynamic coefficient data of the rocket's entire trajectory is through wind tunnel testing or CFD calculation.
[0045] Furthermore, the linearization processing of the aerodynamic coefficient data will... Linearization to ,Will Linearization to The specific method is as follows:
[0046] At each Mach number Under the node, and Within the scope, for Perform linear regression and extract the slope. ;
[0047] At each Mach number Under the node, and Within the scope, for Perform linear regression and extract the slope. .
[0048] In any of the above embodiments, the acquisition of a standard landing reference trajectory data for the rocket includes at least the changes in altitude, velocity, and atmospheric density over time.
[0049] In another aspect, the present invention provides a storage medium on which an executable program is stored, which, when invoked, executes the aerodynamic modeling method for reusable rocket path planning as described in any of the above embodiments.
[0050] The present invention also provides a server comprising at least a memory and a processor, wherein the memory stores an executable program and the processor is configured to invoke the executable program to execute the aerodynamic modeling method for reusable rocket path planning as described in any of the above embodiments.
[0051] The aerodynamic modeling method, storage medium, and server for reusable rocket path planning provided by this invention have at least one of the following beneficial effects:
[0052] First, the aerodynamic modeling method of the present invention has high computational efficiency, and can transform complex multidimensional lookup table operations into simple one-dimensional function calculations or polynomial calculations, significantly reducing the burden on the onboard computer.
[0053] Second, the aerodynamic modeling method of the present invention eliminates the strong nonlinear characteristics of aerodynamics through decoupling and linearization (for angles), making the path planning problem easier to transform into a convex optimization problem, thus ensuring the convergence and solution speed of the algorithm.
[0054] Third, the application of this invention can save fuel. The aerodynamic modeling method of this invention, by explicitly considering aerodynamic forces (especially the contribution of drag to deceleration) in the planning model, can make fuller use of atmospheric deceleration compared to planning methods that ignore aerodynamic forces, thereby saving engine propellant.
[0055] Fourth, the aerodynamic model constructed using the aerodynamic modeling method of this invention closely follows the actual physical constraints of the rocket's vertical landing "small angle of attack" flight, which simplifies the model and meets the accuracy requirements of guidance, and has strong engineering applicability.
[0056] Upon reading the detailed embodiments and examining the accompanying drawings, those skilled in the art will recognize additional features and advantages. Attached Figure Description
[0057] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0058] Figure 1 This is a flowchart of an aerodynamic modeling method for reusable rocket path planning according to an embodiment of the present invention.
[0059] Figure 2 It is a graph showing the relationship between the lift coefficient and the angle of attack at different Mach numbers. Detailed Implementation
[0060] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and to exemplify the principles of the present invention, and are not configured to limit the present invention. In addition, the structural components in the drawings are not necessarily drawn to scale. For example, the dimensions of some structural components or regions in the drawings may be enlarged for other structural components or regions to aid in the understanding of the embodiments of the present invention.
[0061] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the embodiments of the present invention. In the description of the present invention, it should be noted that, unless otherwise stated, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.
[0062] Furthermore, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure or component that includes a list of elements includes not only those elements but also other structural elements that are not expressly listed or inherent to the structure or component. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the article or apparatus that includes the element.
[0063] Spatial relation terms such as "below," "under," "under," "low," "above," "on," and "high" are used for descriptive convenience to explain the positioning of one element relative to a second element, indicating that these terms are intended to cover different orientations of the device, in addition to those different from those shown in the figure. Furthermore, phrases such as "one element on / below another element" can indicate that two elements are in direct contact, or that there are other elements between the two elements. In addition, terms such as "first" and "second" are also used to describe individual elements, areas, parts, etc., and should not be considered limiting. Similar terms are used throughout the description to refer to similar elements.
[0064] It will be apparent to those skilled in the art that the present invention can be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention.
[0065] The present invention aims to solve the problems of low computational efficiency, difficulty in convergence of optimization algorithms, or even inability to solve problems caused by the overly complex and nonlinear aerodynamic models in the landing phase path planning of existing reusable rockets.
[0066] See Figure 1 and Figure 2 This invention provides an aerodynamic modeling method for reusable rocket path planning. Based on the dynamic characteristics of the rocket's landing phase, this method utilizes the small angle-of-attack assumption and velocity correlation decoupling to construct a linearized aerodynamic model. The specific technical solution is as follows:
[0067] S1. Establish the landing coordinate system and the rocket body coordinate system, and set the rocket to be in the powered descent phase during the planning stage, with an angle of attack of [missing information]. and sideslip angle The value of A is limited to the range of [-A, +A], where A ranges from 5° to 10°.
[0068] S2, based on thrust vector Aerodynamic vector and gravity vector Establish the particle dynamics equations of the rocket in the landing coordinate system, and project them onto the landing coordinate system to form a preliminary aerodynamic model: .
[0069] S3. Solve the aerodynamic vector. The method is as follows:
[0070] S31. Obtain the aerodynamic coefficient data of the rocket's entire trajectory and perform linearization processing to form aerodynamic force vectors. Simplify the equation.
[0071] S32. Obtain a standard landing reference trajectory data for the rocket, and based on the velocity profile of the standard reference trajectory, calculate the aerodynamic vector... The simplified equations are encapsulated in terms of velocity only. The product of the function term and the angle:
[0072] .
[0073] S33. A function is obtained by fitting offline aerodynamic data and standard ballistic data. , and ,in, , and Regarding speed A polynomial function or a one-dimensional interpolation function;
[0074] S4. Calculate the aerodynamic vectors. Substituting these values into the initial aerodynamic model, we obtain the final aerodynamic model for path planning:
[0075]
[0076] in, For rocket mass, It is a velocity vector. This is the transition matrix from the rocket body coordinate system to the landing coordinate system, derived from the attitude angles (roll). ,yaw , looking up )Sure; This is the thrust vector in the arrow body coordinate system; This is the gravity vector.
[0077] Furthermore, in the path planning algorithm of the onboard computer, the final dynamic model can be further simplified, specifically as follows:
[0078]
[0079] in, This is the transfer matrix from the arrow system to the landing system. For thrust amplitude, For the mass of the rocket recovery section, For gravitational acceleration; the aerodynamic vector is modeled as depending only on the current velocity. and control variables ( The analytical form of ) can be solved quickly through iteration without the need for table lookup.
[0080] Furthermore, in S1, a landing coordinate system (system) is set. The inertial reference frame is used. The landing coordinate system (frame) is used. ), its origin Located at the ground recycling point, The axis is fixed in direction in the horizontal plane (e.g., north). The axis is perpendicular to the Earth's ellipsoid and points upwards. The axis follows the right-hand screw rule. The rocket is considered a rigid body with an axisymmetric shape; based on this, a simplified coordinate system (system) is established. It is assumed that the rocket is in the powered descent phase during the planning stage, the engine has been ignited, and the rocket has reached an angle of attack... and sideslip angle It is limited to the range of [-A, +A], where A is determined based on the maximum range of the linear characteristics of the aerodynamic coefficient, and is usually taken as 5°~10°.
[0081] Furthermore, S2, based on thrust vector Aerodynamic vector and gravity vector Establish the particle dynamics equations of the rocket in the landing coordinate system, and project them onto the landing coordinate system to form a preliminary aerodynamic model: The specific method is as follows:
[0082] Neglecting non-inertial forces (Coriolis force and entrainment inertial force), we establish the particle dynamics equations of the rocket in the landing system: .in, It is a velocity vector. For thrust vector, It is an aerodynamic vector. This is the gravity vector.
[0083] Projecting the forces from the particle dynamics equations of the landing system onto the landing coordinate system forms a rudimentary aerodynamic model: .in, For the arrow body coordinate system (system) ) to the landing coordinate system (system) The transition matrix is derived from the attitude angle (roll). ,yaw , looking up )Sure. The thrust vector in the rocket body coordinate system. The aerodynamic vector in the rocket body coordinate system. This is the gravity vector.
[0084] In this embodiment, to simplify the aerodynamic vector... The decoupling method improves the solution efficiency and transforms the three-dimensional aerodynamic vector. The decoupling consists of an axial drag term that is only related to velocity, and a normal / lateral aerodynamic term that is the velocity correlation coefficient multiplied by the angle.
[0085] For example, regarding the angle of attack of the rocket during the vertical recovery and landing phase. and sideslip angle In smaller operating conditions, the aerodynamic vectors under the rocket body structure are utilized to achieve the desired effect. Decoupling into axial force Normal force and lateral force .
[0086] The traditional calculation formula is:
[0087]
[0088] This invention simplifies it to:
[0089]
[0090] in, Let be the derivative of the lift coefficient with respect to the angle of attack. This is the derivative of the lateral force coefficient with respect to the sideslip angle. For dynamic pressure, The characteristic area is denoted as .
[0091] Furthermore, S31 acquires the aerodynamic coefficient data of the rocket's entire trajectory and performs linearization processing to form aerodynamic vectors. The specific method for simplifying the equations is as follows:
[0092] Obtain aerodynamic coefficient data for the entire rocket trajectory, including , and ,in, The drag coefficient, The lift coefficient, This is the lateral force coefficient. It is the Mach number;
[0093] Linearization of aerodynamic coefficient data is performed. Linearization to ,Will Linearization to ;
[0094] Among them, the drag coefficient At small angle of attack The following can be approximated as being related only to the Mach number, i.e. ;
[0095] Therefore, the simplified equations for aerodynamic vectors are formed:
[0096] in, Let be the derivative of the lift coefficient with respect to the angle of attack. This is the derivative of the lateral force coefficient with respect to the sideslip angle. For dynamic pressure, The characteristic area is denoted as .
[0097] In this embodiment, the aerodynamic coefficient data is linearized, and... Linearization to ,Will Linearization to The specific method is as follows:
[0098] At each Mach number Under the node, and Within the interval, for Perform linear regression and extract the slope. .
[0099] At each Mach number Under the node, and Within the interval, for Perform linear regression and extract the slope. .
[0100] Where A is determined based on the maximum range of the linear characteristics of the aerodynamic coefficient, typically taken as 5°~10°.
[0101] For reference only. Figure 2 This represents the curve relationship between the lift coefficient and the angle of attack at different Mach numbers.
[0102] It should be noted that the drag coefficient At small angles of attack, it is approximated that it depends only on the Mach number, i.e. .
[0103] Furthermore, considering the dynamic pressure during landing within the atmosphere... Aerodynamic derivatives are mainly related to velocity (or Mach number) Strongly correlated, and feature area This is a constant. Therefore, based on the velocity profile of a standard reference trajectory, this invention further encapsulates the aerodynamic model into one that is only related to velocity. The product of the function term and the angle.
[0104] Specifically, S32, acquire a standard landing reference trajectory data for the rocket, and based on the velocity profile of the standard reference trajectory, calculate the aerodynamic vector... The simplified equations are encapsulated in terms of velocity only. The method for taking the product of the function term and the angle is as follows: obtain a standard landing reference trajectory data for the rocket, and based on the velocity profile of the standard reference trajectory, calculate the aerodynamic vector. Packaged as speed-only The product of the function term and the angle:
[0105]
[0106] Among them, the function , and The velocity was obtained by fitting aerodynamic data and standard ballistic data offline. A polynomial function or a one-dimensional interpolation function.
[0107] Furthermore, in S33, a function is obtained by fitting aerodynamic data and standard ballistic data offline. , and The specific method is as follows:
[0108] After obtaining a standard landing reference trajectory data for the rocket, and combining it with the drag coefficient and slope... Lift coefficient slope and lateral force coefficient slope Calculate the reference or gradient values of aerodynamic components:
[0109]
[0110]
[0111]
[0112] in, This is the reference value for resistance. For the lift gradient, For the lateral force gradient, Current speed;
[0113] With speed Establish a fitting function with the variable as the independent variable:
[0114]
[0115]
[0116]
[0117] Its fitting form can be a higher-order polynomial (such as a 5th-order polynomial): .
[0118] In any of the above embodiments, the aerodynamic coefficient data of the rocket's entire trajectory is obtained through wind tunnel testing or CFD calculation.
[0119] In any of the above embodiments, the standard landing reference trajectory data of the rocket obtained in S32 includes at least the changes in altitude, velocity, and atmospheric density over time.
[0120] To further improve accuracy, the function It can include information about height. Atmospheric density correction factor That is, the form becomes .
[0121] Similarly, and Similar corrections can also be made.
[0122] Furthermore, the aerodynamic modeling method for reusable rocket path planning in this embodiment of the invention further includes: in the path planning algorithm, the final dynamic model is used as part of the equality constraint or objective function; when the rocket body coordinate system is... velocity When in a dominant position, utilize , The approximate relationship transforms aerodynamic forces into a function of velocity state variables, thereby eliminating the explicit dependence of angle control variables on aerodynamic terms and facilitating convex optimization solutions; where, In the arrow body coordinate system The speed of the direction, In the arrow body coordinate system The speed of the direction.
[0123] The aerodynamic modeling method in this embodiment does not directly use a multidimensional aerodynamic coefficient table, but instead combines the atmospheric environment and flight state of a standard ballistic trajectory to calculate the gradient of aerodynamic components (…). Prefitted to be about flight speed The use of univariate analytic functions (such as polynomials) greatly reduces the computational complexity of the arrow.
[0124] The above embodiments can be combined with each other and have corresponding technical effects.
[0125] In another aspect, the present invention provides a storage medium on which an executable program is stored, which, when invoked, executes the aerodynamic modeling method for reusable rocket path planning in any of the above embodiments.
[0126] The present invention also provides a server including a memory and a processor, the memory storing an executable program, and the processor for calling the stored executable program to execute the aerodynamic modeling method for reusable rocket path planning in any of the above embodiments.
[0127] The above embodiments can be combined with each other and have corresponding technical effects.
[0128] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. An aerodynamic modeling method for reusable rocket path planning, characterized in that, At least the following steps are included: Establish the landing coordinate system and the rocket body coordinate system, and set the rocket to be in the powered descent phase during the planning stage, with an angle of attack of [missing information]. and sideslip angle The value of A is limited to the range of [-A, +A], where A ranges from 5° to 10°. Based on thrust vector Aerodynamic vector and gravity vector Establish the particle dynamics equations of the rocket in the landing coordinate system, and project them onto the landing coordinate system to form a preliminary aerodynamic model: ; Solving the aerodynamic vector The method is as follows: The aerodynamic coefficient data of the rocket's entire trajectory are acquired and linearized to form aerodynamic force vectors. Simplify the equations; Obtain a standard landing reference trajectory data for the rocket, and based on the velocity profile of the standard reference trajectory, calculate the aerodynamic vector. The simplified equations are encapsulated in terms of velocity only. The product of the function term and the angle: ； The function was obtained by fitting offline aerodynamic data and standard ballistic data. , and ,in, , and Regarding speed A polynomial function or a one-dimensional interpolation function; The calculated aerodynamic vector Substituting these values into the initial aerodynamic model, we obtain the final aerodynamic model for path planning: in, For rocket mass, It is a velocity vector. This is the transition matrix from the rocket body coordinate system to the landing coordinate system, derived from the attitude angles (roll). ,yaw , looking up )Sure; This is the thrust vector in the arrow body coordinate system; This is the gravity vector.
2. The aerodynamic modeling method for reusable rocket path planning according to claim 1, characterized in that, The aerodynamic coefficient data of the entire rocket trajectory is acquired and linearized to form an aerodynamic vector. The specific method for simplifying the equations is as follows: Obtain aerodynamic coefficient data for the entire rocket trajectory, including , and ,in, The drag coefficient, The lift coefficient, This is the lateral force coefficient. It is the Mach number; Linearization of aerodynamic coefficient data is performed. Linearization to ,Will Linearization to ; Among them, the drag coefficient At small angle of attack The following can be approximated as being related only to the Mach number, i.e. ; Simplified aerodynamic vector equations are formed: in, Let be the derivative of the lift coefficient with respect to the angle of attack. This is the derivative of the lateral force coefficient with respect to the sideslip angle. For dynamic pressure, The characteristic area is denoted as .
3. The aerodynamic modeling method for reusable rocket path planning according to claim 2, characterized in that, Obtain a standard landing reference trajectory data for the rocket, and based on the velocity profile of the standard reference trajectory, calculate the aerodynamic vector. The simplified equations are encapsulated in terms of velocity only. The specific method for obtaining the product of the function term and the angle is as follows: During the rocket's landing in the atmosphere, dynamic pressure The aerodynamic derivative is mainly related to velocity. (or Mach number) strongly correlated, and characteristic area The constant is used; based on this, a standard landing reference trajectory data for the rocket is obtained, and based on the velocity profile of the standard reference trajectory, the aerodynamic vector is... Packaged as speed-only The product of the function term and the angle: 。 4. The aerodynamic modeling method for reusable rocket path planning according to claim 3, characterized in that, The function is obtained by fitting offline aerodynamic data and standard ballistic data. , and The specific method is as follows: After obtaining a standard landing reference trajectory data for the rocket, and combining it with the drag coefficient and slope... Lift coefficient slope and lateral force coefficient slope Calculate the reference or gradient values of aerodynamic components: in, This is the reference value for resistance. For the lift gradient, For the lateral force gradient, Current speed; With speed Establish a fitting function with the variable as the independent variable: Its fitting form can be a high-order polynomial.
5. The aerodynamic modeling method for reusable rocket path planning according to claim 1, characterized in that, In the path planning algorithm of the onboard computer, the final dynamic model is further simplified, specifically as follows: in, This is the transfer matrix from the arrow system to the landing system. For thrust amplitude, For the mass of the rocket recovery section, For gravitational acceleration; the aerodynamic vector is modeled as depending only on the current velocity. and control variables ( The analytical form of ) can be solved quickly through iteration without the need for table lookup.
6. The aerodynamic modeling method for reusable rocket path planning according to claim 5, characterized in that, Also includes: In path planning algorithms, the final dynamic model is used as part of the equality constraints or objective function; When the arrow body coordinate system velocity When in a dominant position, utilize , The approximate relationship transforms aerodynamic forces into a function of velocity state variables, thereby eliminating the explicit dependence of angle control variables on aerodynamic terms and facilitating convex optimization solutions. in, In the arrow body coordinate system The speed of the direction, In the arrow body coordinate system The speed of the direction.
7. The aerodynamic modeling method for reusable rocket path planning according to claim 2, characterized in that, The linearization process of the aerodynamic coefficient data will Linearization to ,Will Linearization to The specific method is as follows: At each Mach number Under the node, and Within the interval, for Perform linear regression and extract the slope. ; At each Mach number Under the node, and Within the interval, for Perform linear regression and extract the slope. .
8. The aerodynamic modeling method for reusable rocket path planning according to any one of claims 1 to 7, characterized in that, The acquisition of a standard landing reference trajectory for the rocket includes at least the changes in altitude, velocity, and atmospheric density over time.
9. A storage medium, characterized in that, It stores an executable program, which, when invoked, executes the aerodynamic modeling method for reusable rocket path planning as described in any one of claims 1-8.
10. A server, characterized in that, It includes a memory and a processor, the memory storing an executable program, and the processor being used to invoke the executable program to execute the aerodynamic modeling method for reusable rocket path planning as described in any one of claims 1-8.