A method for calculating aerodynamic force of carrier rocket considering axis deflection of arrow body
By defining the launch vehicle's coordinate system and axis skew parameters, the total angle of attack and incoming flow azimuth were calculated, solving the aerodynamic calculation problem of the launch vehicle and improving its performance and reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI AEROSPACE SYST ENG INST
- Filing Date
- 2023-06-25
- Publication Date
- 2026-06-12
AI Technical Summary
Existing technologies are not applicable to the aerodynamic models of new launch vehicles based on the total angle of attack and the azimuth of the incoming flow, and cannot effectively calculate the impact of the rocket body axis deviation on the launch vehicle, thus affecting the performance and reliability of the launch vehicle.
By defining the launch vehicle body coordinate system, calculating the body axis skew parameters, transforming to the axis skew body coordinate system, calculating the total angle of attack and the incoming flow azimuth, and then calculating the aerodynamic forces and aerodynamic torque, this method is applicable to the simulation calculation and guidance control of new launch vehicles.
It enables aerodynamic calculations of launch vehicles with axial tilt, improving the performance and reliability of launch vehicles, and allowing for simulation calculations and impact analysis.
Smart Images
Figure CN116776772B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of launch vehicle guidance and control, and in particular to a method for calculating the aerodynamic forces of a launch vehicle considering the axial deviation of the rocket body. Background Technology
[0002] During flight, launch vehicles are inevitably subject to various interferences, causing them to deviate from their intended flight trajectory and produce errors. Among these, the misalignment of the launch vehicle's axis caused by manufacturing and assembly errors results in the axis no longer coinciding with the theoretical axis, altering the shape of the launch vehicle and changing the total angle of attack and the incoming flow azimuth angle. Consequently, this changes the aerodynamic forces acting on the launch vehicle, making it a significant interfering factor.
[0003] Existing aerodynamic calculation methods for launch vehicles considering shaft skew are only applicable to traditional aerodynamic models based on angle of attack and sideslip angle, and cannot be applied to aerodynamic models of new launch vehicles based on total angle of attack and incoming flow azimuth angle. How to calculate the total angle of attack and incoming flow azimuth angle considering shaft skew based on the launch vehicle's relative incoming flow velocity vector and shaft skew parameters, and then calculate the aerodynamic forces and moments acting on the launch vehicle, to achieve launch vehicle simulation calculations considering shaft skew, complete the analysis of the impact of shaft skew on launch vehicle guidance and control, and improve launch vehicle performance and reliability, is a technical problem urgently needing to be solved in this field. Summary of the Invention
[0004] The technical problem solved by this invention is to fill the gap in the existing technology by proposing a method for calculating the aerodynamic forces of a launch vehicle considering the axial deflection of the rocket body. Based on the relative velocity vector of the launch vehicle to the incoming flow and the axial deflection parameters, the total angle of attack and the azimuth angle of the incoming flow considering the axial deflection are calculated, and then the aerodynamic forces and aerodynamic moments acting on the launch vehicle are calculated. This enables the simulation calculation of the launch vehicle considering the axial deflection of the rocket body, completes the analysis of the impact of the axial deflection of the rocket body on the guidance and control of the launch vehicle, and improves the performance and reliability of the launch vehicle.
[0005] The objective of this invention can be achieved through the following technical solutions:
[0006] A method for calculating the aerodynamic forces of a launch vehicle considering the axial deviation of the rocket body includes the following steps:
[0007] Step S1: Define the launch vehicle body coordinate system and obtain the relative incoming flow velocity vector [V] in the launch vehicle body coordinate system. x1 V y1 V z1 ] T ;
[0008] Step S2: Based on the skew parameters of the launch vehicle's body axis, calculate the coordinate transformation matrix from the body coordinate system to the skewed body coordinate system.
[0009] Step S3: Transform the relative incoming velocity vector of the launch vehicle from the rocket body coordinate system to the axis-skewed body coordinate system;
[0010] Step S4: Calculate the total angle of attack α based on the components of the relative incoming velocity vector of the launch vehicle on each coordinate axis of the skewed body coordinate system. Q and the azimuth angle of the incoming flow Φ Q ;
[0011] Step S5: Based on the total angle of attack α Q and the azimuth angle of the incoming flow Φ Q Calculate the aerodynamic forces [R] acting on the launch vehicle. x1 R y1 R z1 ] T and aerodynamic torque [M Rx1 M Ry1 M Rz1 ] T .
[0012] Preferably, in step S1, the rocket body coordinate system is as follows: the origin O of the rocket body coordinate system is the center of mass of the launch vehicle, the OX1 axis points to the head along the theoretical rocket body axis, the OY1 axis is in the longitudinal symmetry plane of the launch vehicle, perpendicular to the OX1 axis and pointing to the reference direction, and the OZ1 axis, together with the OX1 axis and the OY1 axis, forms a right-handed coordinate system.
[0013] Preferably, in step S2, the arrow body axis deviation parameters include the axis deviation angle η and the axis deviation direction angle ρ;
[0014] Wherein, the axis deviation angle η is the angle between the arrow body axis vector and the OX1 axis in the arrow body coordinate system;
[0015] The axial deviation angle ρ is the angle between the OY1 axis in the rocket body coordinate system and the projection of the rocket body axis vector onto the Y1OZ1 plane of the rocket body coordinate system; where the rocket head is viewed from the front, and counterclockwise rotation is considered positive.
[0016] Preferably, in step S2, the coordinate transformation matrix from the rocket body coordinate system to the axis skew body coordinate system is... The calculation method is as follows:
[0017]
[0018] Where ρ is the axial deviation direction angle and η is the axial deviation angle.
[0019] Preferably, in step S3, the axis-skewed body coordinate system is: the origin O of the axis-skewed body coordinate system is the center of mass of the launch vehicle, OX... t The axis points towards the nose along the actual axis of the launch vehicle.t The axis lies in the longitudinal symmetry plane of the launch vehicle and is perpendicular to OX. t The axis points in the reference direction, OZ t Axis and OX t Axis, OY t The axes form a right-handed coordinate system.
[0020] Preferably, in step S3, the relative incoming flow velocity vector of the launch vehicle is transformed from the rocket body coordinate system to the axis-skewed body coordinate system, and the calculation method is as follows:
[0021]
[0022] Among them, [V tx V ty V tz ] T This represents the relative incoming flow velocity vector in the skewed body coordinate system. For coordinate transformation matrix, [V x1 V y1 V z1 ] T This is the relative incoming flow velocity vector in the arrow body coordinate system.
[0023] Preferably, in step S4, the total angle of attack α Q The angle between the vector of the relative incoming velocity of the launch vehicle and the OX1 axis in the launch vehicle coordinate system.
[0024] Preferably, in step S4, the round-trip azimuth angle Φ Q For the negative OY coordinate system of the axis skewed body coordinate system t The relative velocity vector of the incoming flow from the axis to the launch vehicle in the rocket body coordinate system Y t OZ t The angle between the projections on the plane, where the rocket's nose is viewed from the front, and a counterclockwise rotation is considered positive.
[0025] Preferably, in step S4, the total angle of attack α is calculated. Q and the azimuth angle of the incoming flow Φ Q Furthermore, the calculation method is as follows:
[0026]
[0027]
[0028] In the skewed body coordinate system, V tx Indicates the relative inflow velocity in OX t The component in the axial direction, V ty Indicates the relative inflow velocity in OY t The component in the axial direction, V tzIndicates the relative inflow velocity in oz. t The component along the axial direction.
[0029] Preferably, in step S5, the aerodynamic forces [R] acting on the launch vehicle are calculated. x1 R y1 R z1 ] T and aerodynamic torque [M Rx1 M Ry1 M Rz1 ] T Further including:
[0030] Calculate aerodynamic forces [R] x1 R y1 R z1 ] T :
[0031]
[0032] Where q is the dynamic pressure, S is the characteristic area, and C x1 C is the axial force coefficient. n C is the normal force coefficient. x1 and C n All are at total angle of attack α Q , Incoming flow azimuth Φ Q A function of Mach number;
[0033] Calculate aerodynamic torque [M] Rx1 M Ry1 M Rz1 ] T :
[0034]
[0035] Among them, [L Rx1 L Ry1 L Rz1 ] T Let [L] be the position vector of the aerodynamic center of pressure in the rocket body coordinate system. Rx1 L Ry1 L Rz1 ] T It is the overall attack angle α Q It is a function of Mach number, which is the ratio of the launch vehicle's velocity to the speed of sound in the surrounding medium.
[0036] Compared with the prior art, the present invention has at least one of the following technical advantages:
[0037] This invention proposes a method for calculating the aerodynamic forces of a launch vehicle considering the deflection of its axis. It is the first to propose a method for calculating the total angle of attack and the incoming flow azimuth angle, taking into account the axis deflection angle and the direction of axis deflection. This solves the problem of calculating the aerodynamic forces of a launch vehicle considering the deflection of its axis. The invention is simple in principle, easy to implement in engineering, and applicable to aerodynamic models of new launch vehicles based on the total angle of attack and the incoming flow azimuth angle. It enables simulation calculations of launch vehicles considering the deflection of their axis, thereby completing the analysis of the impact of the deflection of the axis on the launch vehicle and improving its performance and reliability. Attached Figure Description
[0038] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:
[0039] Figure 1 This is a flowchart of a method for calculating the aerodynamic forces of a launch vehicle that takes into account the axial deviation of the rocket body, according to the present invention.
[0040] Figure 2 This is a schematic diagram of the axis deviation direction angle in the aerodynamic calculation method for a launch vehicle considering the axis deviation of the rocket body according to the present invention;
[0041] Figure 3 This is a schematic diagram of the incoming flow azimuth angle in a method for calculating the aerodynamic forces of a launch vehicle that considers the axial deviation of the rocket body, as described in this invention. Detailed Implementation
[0042] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0043] Example 1
[0044] This invention provides a method for calculating the aerodynamic forces of a launch vehicle considering the axial deviation of the rocket body. Please refer to [link / reference]. Figure 1 , Figure 1 This is a flowchart of a method for calculating the aerodynamic forces of a launch vehicle considering the axial deviation of the rocket body, according to the present invention, including the following steps:
[0045] Step S1: Define the launch vehicle body coordinate system and obtain the relative incoming flow velocity vector [V] in the launch vehicle body coordinate system. x1 V y1 V z1 ] T ;
[0046] Step S2: Based on the skew parameters of the launch vehicle's body axis, calculate the coordinate transformation matrix from the body coordinate system to the skewed body coordinate system.
[0047] Step S3: Transform the relative incoming velocity vector of the launch vehicle from the rocket body coordinate system to the axis-skewed body coordinate system;
[0048] Step S4: Calculate the total angle of attack α based on the components of the relative incoming velocity vector of the launch vehicle on each coordinate axis of the skewed body coordinate system. Q and the azimuth angle of the incoming flow Φ Q ;
[0049] Step S5: Based on the total angle of attack α Q and the azimuth angle of the incoming flow Φ Q Calculate the aerodynamic forces [R] acting on the launch vehicle. x1 R y1 R z1 ] T and aerodynamic torque [M Rx1 M Ry1 M Rz1 ] T .
[0050] Preferably, in step S1, the rocket body coordinate system is as follows: the origin O of the rocket body coordinate system is the center of mass of the launch vehicle, the OX1 axis points to the head along the theoretical rocket body axis, the OY1 axis is in the longitudinal symmetry plane of the launch vehicle, perpendicular to the OX1 axis and pointing to the reference direction, and the OZ1 axis, together with the OX1 axis and the OY1 axis, forms a right-handed coordinate system.
[0051] Preferably, in step S2, the arrow body axis deviation parameters include the axis deviation angle η and the axis deviation direction angle ρ;
[0052] Wherein, the axis deviation angle η is the angle between the rocket body axis vector (from the center of mass of the launch vehicle to the head) and the OX1 axis (the theoretical rocket body axis vector) in the rocket body coordinate system;
[0053] The axial deviation angle ρ is the angle between the OY1 axis in the rocket body coordinate system and the projection of the rocket body axis vector (from the center of mass of the launch vehicle to the head) onto the Y1OZ1 plane of the rocket body coordinate system; where the launch vehicle head is viewed from the front, and counterclockwise rotation is positive.
[0054] Please see Figure 2 ,Figure 2 This is a schematic diagram of the axis deviation direction angle in the aerodynamic calculation method for a launch vehicle considering the axis deviation of the rocket body according to the present invention;
[0055] In the diagram, OA xoy ρ is the projection of the rocket body axis vector (the center of mass of the launch vehicle points to the head) onto the Y1OZ1 plane of the rocket body coordinate system, and ρ is the axial deviation direction angle.
[0056] Preferably, in step S2, the coordinate transformation matrix from the rocket body coordinate system to the axis skew body coordinate system is... The calculation method is as follows:
[0057]
[0058] Where ρ is the axial deviation direction angle and η is the axial deviation angle.
[0059] Preferably, in step S3, the axis-skewed body coordinate system is: the origin O of the axis-skewed body coordinate system is the center of mass of the launch vehicle, OX... t The axis points towards the nose along the actual axis of the launch vehicle. t The axis lies in the longitudinal symmetry plane of the launch vehicle and is perpendicular to OX. t The axis points in the reference direction, OZ t Axis and OX t Axis, OY t The axes form a right-handed coordinate system.
[0060] Preferably, in step S3, the relative incoming flow velocity vector of the launch vehicle is transformed from the rocket body coordinate system to the axis-skewed body coordinate system, and the calculation method is as follows:
[0061]
[0062] Among them, [V tx V ty V tz ] T This represents the relative incoming flow velocity vector in the skewed body coordinate system. For coordinate transformation matrix, [V x1 V y1 V z1 ] T This is the relative incoming flow velocity vector in the arrow body coordinate system.
[0063] Preferably, in step S4, the total angle of attack α Q The angle between the vector of the relative incoming velocity of the launch vehicle and the OX1 axis in the launch vehicle coordinate system.
[0064] Preferably, in step S4, the round-trip azimuth angle Φ Q For the negative OY coordinate system of the axis skewed body coordinate systemt The relative velocity vector of the incoming flow from the axis to the launch vehicle in the rocket body coordinate system Y t OZ t The angle between the projections on the plane, where the rocket's nose is viewed from the front, and a counterclockwise rotation is considered positive.
[0065] Please see Figure 3 , Figure 3 This is a schematic diagram of the incoming flow azimuth angle in a method for calculating the aerodynamic forces of a launch vehicle that considers the axial deviation of the rocket body, as described in this invention.
[0066] In the diagram, OV txoy The velocity vector of the launch vehicle relative to the incoming flow in the skewed body coordinate system Y is... t OZ t Projection on a plane, Φ Q The angular deviation of the axis is denoted by θ.
[0067] Preferably, in step S4, the total angle of attack α is calculated. Q and the azimuth angle of the incoming flow Φ Q Furthermore, the calculation method is as follows:
[0068]
[0069]
[0070] In the skewed body coordinate system, V tx Indicates the relative inflow velocity in OX t The component in the axial direction, V ty Indicates the relative inflow velocity in OY t The component in the axial direction, V tz Indicates the relative inflow velocity in oz. t The component along the axial direction.
[0071] Preferably, by calculating the total angle of attack α Q and the azimuth angle of the incoming flow Φ Q This process obtains information about the direction and angle of the relative incoming flow, and then calculates the aerodynamic forces and aerodynamic torques. In step S5, the aerodynamic forces [R] acting on the launch vehicle are calculated. x1 R y1 R z1 ] T and aerodynamic torque [M Rx1 M Ry1 M Rz1 ] T Further including:
[0072] Calculate aerodynamic forces [R] x1 R y1 R z1 ]T :
[0073]
[0074] Where q is dynamic pressure, representing the pressure of the launch vehicle in the airflow, which is proportional to the square of the relative incoming flow velocity, and S is characteristic area, which is the effective area where the launch vehicle intersects with the airflow in the flow.
[0075] C x1 C is the axial force coefficient. n C is the normal force coefficient. x1 =f(α) Q , Φ Q M), C n =f(α) Q , Φ Q M), where M is the Mach number, used to represent the ratio of the launch vehicle's velocity to the speed of sound in the surrounding medium; C x1 and C n All are at total angle of attack α Q , Incoming flow azimuth Φ Q It is a function of Mach number; the specific functional relationship depends on the aerodynamic characteristics and geometry of the launch vehicle or other aircraft, as well as the aerodynamic calculation model or experimental data used. Different aircraft types and aerodynamic models may have different formulaic expressions.
[0076] [R x1 R y1 R z1 ] T This indicates the magnitude and direction of the aerodynamic force components acting on the launch vehicle along the OX1, OY1, and OZ1 axes. By calculating these aerodynamic force components, the magnitude and direction of the aerodynamic force acting on the rocket in different directions can be evaluated, which is crucial for analyzing the rocket's stability, control characteristics, and performance.
[0077] Calculate aerodynamic torque [M] Rx1 M Ry1 M Rz1 ] T :
[0078]
[0079] Among them, [L Rx1 L Ry1 L Rz1 ] T The aerodynamic center of pressure is the position vector of the aerodynamic center of pressure in the rocket body coordinate system. The aerodynamic center of pressure is a key parameter describing aerodynamic forces and moments; it refers to the position vector of the aerodynamic center of pressure relative to a reference point in the rocket body coordinate system. [L] Rx1 L Ry1 L Rz1 ]T It is the overall attack angle α Q It is a function of Mach number, which is the ratio of the launch vehicle's velocity to the speed of sound in the surrounding medium.
[0080] The calculation of aerodynamic torque is crucial for evaluating the stability, handling characteristics, and attitude adjustment capabilities of a rocket. By calculating aerodynamic torque, the magnitude and direction of the rotational torque generated by the aerodynamic forces acting on the launch vehicle can be described, thereby evaluating the rocket's rotational motion characteristics, attitude stability, and designing and optimizing the control system.
[0081] In summary, aerodynamic forces and aerodynamic moments together describe the forces and moments experienced by a launch vehicle in the airflow. Aerodynamic forces affect the launch vehicle's motion and forces in different directions, while aerodynamic moments describe the rotational torque experienced by the rocket in the airflow, affecting its attitude and stability. By understanding the aerodynamic forces and moments experienced by the rocket, its flight trajectory can be optimized.
[0082] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.
Claims
1. A method for calculating the aerodynamic forces of a launch vehicle considering the axial deviation of the rocket body, characterized in that, Includes the following steps: Step S1: Define the launch vehicle body coordinate system and obtain the relative incoming flow velocity vector in the launch vehicle body coordinate system. Wherein, the arrow body coordinate system is: the origin of the arrow body coordinate system. The center of mass of the launch vehicle is [the point of mass]. The axis points towards the nose along the theoretical axis of the launch vehicle. The axis lies in the longitudinal plane of symmetry of the launch vehicle and is perpendicular to the plane of symmetry. The axis points in the reference direction. shaft and the Shaft, the aforementioned The axes form a right-handed coordinate system; Step S2: Based on the skew parameters of the launch vehicle's body axis, calculate the coordinate transformation matrix from the body coordinate system to the skewed body coordinate system. The arrow body axis deviation parameters include the axis deviation angle. and axis deviation direction angle The axial deviation angle The vector of the arrow body axis and the vector in the arrow body coordinate system The included angle between the axes; the skew angle of the axis The coordinate system of the rocket body The vector from the axis to the arrow body axis in the arrow body coordinate system The angle between the projections on the plane; where the rocket's nose is viewed from the front, and a counterclockwise rotation is considered positive; Step S3: Transform the relative incoming flow velocity vector of the launch vehicle from the rocket body coordinate system to the axis skew body coordinate system; wherein, the calculation method for transforming the relative incoming flow velocity vector of the launch vehicle from the rocket body coordinate system to the axis skew body coordinate system is as follows: ； The relative incoming flow velocity vector in the skewed body coordinate system of the axis is given. The coordinate transformation matrix, The relative incoming flow velocity vector in the rocket body coordinate system; Step S4: Calculate the total angle of attack based on the components of the relative incoming flow velocity vector of the launch vehicle on each coordinate axis of the axial skew body coordinate system. and incoming flow azimuth In step S4, the total angle of attack The vector of the relative incoming flow velocity of the launch vehicle and the vector in the rocket body coordinate system. The included angle between the axes; the azimuth angle of the incoming flow The negative coordinate system of the axis skewed The relative incoming flow velocity vector from the axis to the launch vehicle in the rocket body coordinate system The angle between the projections on the plane, where the rocket's nose is viewed from the front and a counterclockwise rotation is considered positive; Step S5: Based on the total angle of attack and the incoming flow azimuth angle Calculate the aerodynamic forces acting on the launch vehicle. and aerodynamic torque .
2. The method for calculating the aerodynamic forces of a launch vehicle according to claim 1, characterized in that, In step S2, the coordinate transformation matrix from the rocket body coordinate system to the axis skew body coordinate system... The calculation method is as follows: ； in, The skew angle of the axis. The skew angle of the axis is [value missing].
3. The method for calculating the aerodynamic forces of a launch vehicle according to claim 1, characterized in that, In step S3, the axis skew body coordinate system is: the origin of the axis skew body coordinate system. The center of mass of the launch vehicle is... The axis points towards the nose along the actual axis of the launch vehicle. The axis lies in the longitudinal plane of symmetry of the launch vehicle and is perpendicular to the plane of symmetry. The axis points in the reference direction. shaft and the Shaft, the aforementioned The axes form a right-handed coordinate system.
4. The method for calculating the aerodynamic forces of a launch vehicle according to claim 3, characterized in that, In step S4, the total angle of attack is calculated. and incoming flow azimuth Furthermore, the calculation method is as follows: ； ； Specifically, in the axially skewed body coordinate system... The relative inflow velocity is indicated in the Components in the axial direction, The relative inflow velocity is indicated in the Components in the axial direction, The relative inflow velocity is indicated in the The component along the axial direction.
5. The method for calculating the aerodynamic forces of a launch vehicle according to claim 1, characterized in that, In step S5, the aerodynamic forces acting on the launch vehicle are calculated. and aerodynamic torque Further including: Calculate the aerodynamic force : in, For dynamic pressure, For the characteristic area, This is the axial force coefficient. Normal force coefficient, and All are the total angle of attack. The azimuth angle of the incoming flow A function of Mach number; Calculate the aerodynamic torque : ； in, The position vector of the aerodynamic center of pressure in the rocket body coordinate system. The total angle of attack is mentioned. The speed of the launch vehicle is a function of the Mach number, which is the ratio of the speed of sound of the launch vehicle to the speed of sound of the surrounding medium.