Electromagnetic launch rocket trajectory optimization method

Abstract

This invention discloses a method for optimizing the trajectory of an electromagnetic launch rocket, comprising: S100 determining multiple initial trajectory inclination angles; S102 trajectory calculation; S104 checking if the orbital insertion conditions are met (if yes, proceed to S106; otherwise, proceed to S118); S106 checking if the overload constraint conditions are met (if yes, proceed to S108; otherwise, proceed to S118); S108 calculating multiple objective function output values; S110 determining if the difference between two adjacent calculated objective function output values ​​is less than a predetermined difference (if yes, proceed to S112); S112 optimizing the trajectory of the rocket corresponding to the maximum orbital payload mass. Initially, determine the initial trajectory inclination angle. Check if the maximum dynamic pressure is not greater than the predetermined dynamic pressure and if the product of the maximum dynamic pressure and the angle of attack is not greater than the predetermined product. If yes, proceed to S114; otherwise, proceed to S116. In S114, determine the initial trajectory inclination angle corresponding to the maximum orbital payload mass as the optimal initial launch inclination angle. In S116, for the remaining initial trajectory inclination angles, perform the same checks as in S112 until the check result is yes, and determine the initial trajectory inclination angle corresponding to the check result as the optimal initial launch inclination angle. In S118, adjust other rocket-related parameters and return to S102.

Description

Technical Field

[0001] This invention relates to the field of aircraft ballistic design technology, and in particular to a method for optimizing the trajectory of an electromagnetic launch rocket. Background Technology

[0002] Most existing rockets are launched vertically from the ground, with an initial velocity of 0 and an initial trajectory inclination of 90°. The trajectory design of vertically launched rockets is relatively mature. Generally, they first undergo a vertical flight, then enter a programmed turn, and then maintain an angle of attack near zero before the rocket flies into orbit under the influence of gravity.

[0003] Under current technology, the payload capacities of 30-ton-class solid-propellant launch vehicles targeting a 500km sun-synchronous orbit are as follows: "Kuaizhou-1A": 220kg; "Jielong-1": 200kg; "Hyperbola-1": 260kg. It can be seen that the payload capacities of vertically launched rockets from the ground are basically equivalent, and the benefits of trajectory optimization are relatively limited. Therefore, a method for electromagnetic launch rockets that can increase the effective payload without significantly increasing the takeoff mass is needed. Summary of the Invention

[0004] This invention provides a method for optimizing the trajectory of an electromagnetic launch rocket, which can solve the technical problems in the prior art.

[0005] This invention provides a method for optimizing the trajectory of an electromagnetic launch rocket, wherein the method includes:

[0006] S100, within the range of initial trajectory inclination angles, determine multiple initial trajectory inclination angles at predetermined intervals;

[0007] S102, for multiple initial trajectory inclination angles, performs trajectory calculations based on initial velocity, initial altitude and other rocket-related parameters to obtain the orbital payload mass, dynamic pressure, product of dynamic pressure and angle of attack, orbital altitude, velocity and trajectory inclination angle of the rocket at the orbital insertion point for each initial trajectory inclination angle.

[0008] S104. Determine whether the orbital altitude of the rocket at the entry point corresponding to each initial trajectory inclination angle, the velocity of the rocket at the entry point corresponding to each initial trajectory inclination angle, and the trajectory inclination angle of the rocket at the entry point corresponding to each initial trajectory inclination angle meet the entry conditions. If yes, proceed to S106; otherwise, proceed to S118.

[0009] S106, determine whether the rocket overload corresponding to each initial trajectory inclination angle meets the overload constraint condition. If yes, go to S108; otherwise, go to S118.

[0010] S108, for multiple initial trajectory inclination angles, calculate multiple objective function output values ​​based on the objective function, wherein the objective function is... α is the angle of attack, and m is the angle of attack. z The mass of the payload to orbit, k1 and k2 are weighting factors, and J is the output value of the objective function;

[0011] S110, determine whether the difference between two consecutive calculated objective function output values ​​is less than a predetermined difference. If so, proceed to S112.

[0012] S112, for the initial trajectory inclination angle corresponding to the maximum orbital payload mass, determine whether the maximum dynamic pressure throughout the flight is not greater than the predetermined dynamic pressure and whether the product of the maximum dynamic pressure and the angle of attack is not greater than the predetermined product. If yes, proceed to S114; otherwise, proceed to S116.

[0013] S114, the initial trajectory inclination angle corresponding to the maximum orbital payload mass is determined as the optimal initial launch inclination angle;

[0014] S116, For the initial trajectory inclination angles corresponding to the other orbital payload masses besides the maximum orbital payload mass, perform the same judgment as S112 in sequence until the judgment result is yes, then determine the initial trajectory inclination angle corresponding to the judgment result as the optimal initial launch inclination angle.

[0015] S118, adjust other rocket-related parameters, and return to S102.

[0016] Preferably, the method further includes:

[0017] If the difference between two consecutive calculated objective function output values ​​is not less than a predetermined difference, determine whether the current iteration number is less than the maximum predetermined iteration number. If yes, return to S108; otherwise, end.

[0018] Preferably, determining whether the rocket overload corresponding to each initial trajectory inclination angle satisfies the overload constraint condition includes:

[0019] Compare the rocket's axial overload corresponding to each initial trajectory inclination angle with the predetermined axial overload;

[0020] Compare the rocket's lateral overload corresponding to each initial trajectory inclination angle with the predetermined lateral overload;

[0021] If the corresponding rocket axial overload is not greater than the predetermined axial overload and the corresponding rocket lateral overload is not greater than the predetermined lateral overload, then the corresponding rocket overload is determined to meet the overload constraint condition; otherwise, the overload constraint condition is not met.

[0022] Preferably, the initial trajectory inclination angle ranges from 30° to 90°, with a predetermined interval of 5° or 10°.

[0023] Preferably, other rocket-related parameters include the maximum angle of attack of the first stage powered segment, the rate of change of the angle of attack of the first stage powered segment, the maximum angle of attack of the second stage powered segment, the rate of change of the angle of attack of the second stage powered segment, the maximum angle of attack of the third stage powered segment, the rate of change of the angle of attack of the third stage powered segment, and the glide time.

[0024] The above technical solutions utilize electromagnetic propulsion technology to provide rockets with a larger initial velocity. By optimizing the initial launch trajectory angle, the flight trajectory of electromagnetic launch rockets can be further optimized, thereby increasing their carrying capacity. Attached Figure Description

[0025] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0026] Figure 1 A flowchart of an electromagnetic launch rocket trajectory optimization method according to an embodiment of the present invention is shown;

[0027] Figure 2 A schematic diagram comparing the mass of the orbital payload according to an embodiment of the present invention is shown. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0031] Figure 1 A flowchart of an electromagnetic launch rocket trajectory optimization method according to an embodiment of the present invention is shown.

[0032] In this invention, electromagnetic propulsion technology can be used to provide the rocket with a large initial velocity, enabling electromagnetic launch. The initial trajectory inclination angle can be achieved by changing the orbital angle. Taking a 30-ton solid-propellant launch vehicle as an example, the optimal initial launch inclination angle can be obtained by optimizing the initial trajectory inclination angle to maximize the effective payload mass of the rocket into orbit.

[0033] like Figure 1 As shown, this embodiment of the invention provides a method for optimizing the trajectory of an electromagnetic launch rocket, wherein the method includes:

[0034] S100, within the range of initial trajectory inclination angles, determine multiple initial trajectory inclination angles at predetermined intervals;

[0035] S102, for multiple initial trajectory inclination angles, performs trajectory calculations based on initial velocity, initial altitude and other rocket-related parameters to obtain the orbital payload mass, dynamic pressure, product of dynamic pressure and angle of attack, orbital altitude, velocity and trajectory inclination angle of the rocket at the orbital insertion point for each initial trajectory inclination angle.

[0036] The initial velocity and initial altitude can be selected and determined based on the level of electromagnetic launch technology, and this invention does not limit them. For example, the initial velocity can be 500 m / s, and the initial altitude can be 3000 m. Furthermore, the target orbit can also be predetermined; for example, the target orbit can be a 300-500 km sun-synchronous orbit. To avoid obscuring this invention, further details are omitted here.

[0037] S104. Determine whether the orbital altitude of the rocket at the entry point corresponding to each initial trajectory inclination angle, the velocity of the rocket at the entry point corresponding to each initial trajectory inclination angle, and the trajectory inclination angle of the rocket at the entry point corresponding to each initial trajectory inclination angle meet the entry conditions. If yes, proceed to S106; otherwise, proceed to S118.

[0038] S106, determine whether the rocket overload corresponding to each initial trajectory inclination angle meets the overload constraint condition. If yes, go to S108; otherwise, go to S118.

[0039] S108, for multiple initial trajectory inclination angles, calculate multiple objective function output values ​​based on the objective function, wherein the objective function is... α is the angle of attack, and m is the angle of attack. z The mass of the payload to orbit, k1 and k2 are weighting factors, and J is the output value of the objective function;

[0040] Among them, the effective payload mass m z The goal is to maximize the angle of attack α, and a Lagrange integral term can be introduced to obtain a control law with a smoothly changing angle of attack α and low control energy.

[0041] S110, determine whether the difference between two consecutive calculated objective function output values ​​is less than a predetermined difference. If so, proceed to S112.

[0042] For example, the pre-determined difference can be 0.

[0043] S112, for the initial trajectory inclination angle corresponding to the maximum orbital payload mass, determine whether the maximum dynamic pressure throughout the flight is not greater than the predetermined dynamic pressure and whether the product of the maximum dynamic pressure and the angle of attack is not greater than the predetermined product. If yes, proceed to S114; otherwise, proceed to S116.

[0044] For example, the predetermined dynamic pressure can be 155 kPa, and the predetermined product can be 1000 kPa·°.

[0045] S114, the initial trajectory inclination angle corresponding to the maximum orbital payload mass is determined as the optimal initial launch inclination angle;

[0046] In other words, if the maximum dynamic pressure is not greater than the predetermined dynamic pressure and the product of the maximum dynamic pressure and the angle of attack is not greater than the predetermined product, then the initial trajectory inclination angle corresponding to the maximum orbital payload mass can be determined as the optimal initial launch inclination angle.

[0047] S116, For the initial trajectory inclination angles corresponding to the other orbital payload masses besides the maximum orbital payload mass, perform the same judgment as S112 in sequence until the judgment result is yes, then determine the initial trajectory inclination angle corresponding to the judgment result as the optimal initial launch inclination angle.

[0048] For example, if the initial trajectory inclination corresponding to the maximum payload mass is not the optimal initial launch inclination, the same judgment can be made using the initial trajectory inclination corresponding to the second largest payload mass. If the initial trajectory inclination corresponding to the second largest payload mass is also not the optimal initial launch inclination, the same judgment can be made using the initial trajectory inclination corresponding to the third largest payload mass, and so on, until the optimal initial launch inclination is determined.

[0049] S118, adjust other rocket-related parameters, and return to S102.

[0050] The above technical solutions utilize electromagnetic propulsion technology to provide rockets with a larger initial velocity. By optimizing the initial launch trajectory angle, the flight trajectory of electromagnetic launch rockets can be further optimized, thereby increasing their carrying capacity.

[0051] According to one embodiment of the present invention, the method further includes:

[0052] If the difference between two consecutive calculated objective function output values ​​is not less than a predetermined difference, determine whether the current iteration number is less than the maximum predetermined iteration number. If yes, return to S108; otherwise, end.

[0053] By determining the number of iterations, the reliability and accuracy of ballistic optimization can be improved.

[0054] According to one embodiment of the present invention, determining whether the rocket overload corresponding to each initial trajectory inclination angle satisfies the overload constraint condition includes:

[0055] Compare the rocket's axial overload corresponding to each initial trajectory inclination angle with the predetermined axial overload;

[0056] Compare the rocket's lateral overload corresponding to each initial trajectory inclination angle with the predetermined lateral overload;

[0057] If the corresponding rocket axial overload is not greater than the predetermined axial overload and the corresponding rocket lateral overload is not greater than the predetermined lateral overload, then the corresponding rocket overload is determined to meet the overload constraint condition; otherwise, the overload constraint condition is not met.

[0058] In other words, rocket overload includes both axial and lateral overload. For any initial trajectory inclination angle, if the corresponding axial overload is no greater than a predetermined axial overload and the corresponding lateral overload is no greater than a predetermined lateral overload, then the rocket overload corresponding to this initial trajectory inclination angle satisfies the overload constraint condition. The predetermined axial and lateral overloads can be determined based on the rocket's overload tolerance.

[0059] For example, the predetermined axial overload can be 10g, while the predetermined lateral overload can be 1g.

[0060] According to one embodiment of the present invention, the initial trajectory inclination angle ranges from 30° to 90°, and the predetermined interval is 5° or 10°.

[0061] According to one embodiment of the present invention, other rocket-related parameters include the maximum angle of attack of the first stage powered segment, the rate of change of the angle of attack of the first stage powered segment, the maximum angle of attack of the second stage powered segment, the rate of change of the angle of attack of the second stage powered segment, the maximum angle of attack of the third stage powered segment, the rate of change of the angle of attack of the third stage powered segment, and the glide time.

[0062] The electromagnetic launch rocket trajectory optimization method of the present invention will be described below with reference to examples.

[0063] In this example, a 30-ton solid-propellant launch vehicle is used as the carrier, and the optimization objective is to maximize the rocket's mass into orbit, thereby optimizing the initial trajectory inclination angle. The initial trajectory inclination angles can be determined as 30°, 40°, 50°, 60°, 70°, 80°, and 90°, with a launch mass of 30 tons and an initial velocity of 500 m / s.

[0064] According to the steps in the method described in the foregoing embodiments, the orbital payload mass under different initial trajectory inclination angles can be calculated, as shown in Table 1 below.

[0065] Table 1 Summary of Orbital Payload Mass Results

[0066]

[0067] From Table 1 and Figure 2 As can be seen, at an initial trajectory inclination angle of 50°, the effective payload mass to orbit is the largest, approximately 501 kg (i.e., the payload capacity of this invention is twice that of a ground-based vertically launched rocket). The mass to orbit decreases as the angle increases and decreases.

[0068] According to the steps in the method described in the foregoing embodiments, the dynamic pressure of the rocket during the entire flight under different initial trajectory inclination angles can be calculated, and the maximum dynamic pressure is shown in Table 2 below.

[0069] Table 2 Summary of Maximum Dynamic Pressure Results

[0070] Initial trajectory inclination, ° 30° 40° 50° 60° 70° 80° 90° Maximum dynamic pressure, kPa 213.25 165.63 153.13 153.13 153.13 153.13 153.13

[0071] In terms of dynamic pressure, due to the high speed generated by the electromagnetic launch system during the ground phase, except for initial trajectory inclination angles of 30° and 40°, the point of maximum dynamic pressure is the moment before the first-stage engine ignites, i.e., the point of separation from the skid. However, at initial trajectory inclination angles of 30° and 40°, because the initial angle is too low, the launch vehicle needs to perform a certain pitching or fixed pitching angle flight, causing the dynamic pressure to show a trend of first increasing and then decreasing, with a relatively large maximum dynamic pressure.

[0072] According to the steps in the method described in the foregoing embodiments, the product of the maximum dynamic pressure and the angle of attack (i.e., qα, where q represents dynamic pressure and α is the angle of attack) under different initial ballistic inclination angles can be calculated, as shown in Table 3 below.

[0073] Table 3 Summary of Maximum qα Results

[0074]

[0075] In summary, the initial trajectory inclination angle of 50° results in the largest payload mass to orbit. Its maximum dynamic pressure is 153.13 kPa, meeting the requirement of ≤155 kPa. The maximum qα is 465.36 kPa·°, meeting the requirement of ≤1000 kPa·°. Therefore, the overall performance is optimal with an initial trajectory inclination angle of 50°, and this initial trajectory inclination angle can be determined as the optimal initial launch inclination angle.

[0076] Those skilled in the art should understand that the numerical descriptions in this invention are merely exemplary and not intended to limit the invention.

[0077] In this invention, the rocket can utilize electromagnetic propulsion technology to provide powerful acceleration capabilities, reaching supersonic speeds on the ground. It is then elevated via an orbit to a suitable initial trajectory angle (i.e., the optimal initial launch angle), acquiring enormous initial kinetic energy and thus enhancing its payload capacity. This achieves a doubling of the effective payload mass into orbit while maintaining the same takeoff mass.

[0078] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0079] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0080] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for optimizing the trajectory of an electromagnetically launched rocket, characterized in that, The method includes: S100, within the range of initial trajectory inclination angles, determine multiple initial trajectory inclination angles at predetermined intervals; S102, for multiple initial trajectory inclination angles, performs trajectory calculations based on initial velocity, initial altitude and other rocket-related parameters to obtain the orbital payload mass, dynamic pressure, product of dynamic pressure and angle of attack, orbital altitude, velocity and trajectory inclination angle of the rocket at the orbital insertion point for each initial trajectory inclination angle. S104. Determine whether the orbital altitude of the rocket at the entry point corresponding to each initial trajectory inclination angle, the velocity of the rocket at the entry point corresponding to each initial trajectory inclination angle, and the trajectory inclination angle of the rocket at the entry point corresponding to each initial trajectory inclination angle meet the entry conditions. If yes, proceed to S106; otherwise, proceed to S118. S106, determine whether the rocket overload corresponding to each initial trajectory inclination angle meets the overload constraint condition. If yes, go to S108; otherwise, go to S118. S108, for multiple initial trajectory inclination angles, calculate multiple objective function output values ​​based on the objective function, wherein the objective function is... , For the angle of attack, For the effective payload mass upon entry into orbit, As a weighting factor, Output the value of the objective function; S110, determine whether the difference between two consecutive calculated objective function output values ​​is less than a predetermined difference. If so, proceed to S112. S112, for the initial trajectory inclination angle corresponding to the maximum orbital payload mass, determine whether the maximum dynamic pressure throughout the flight is not greater than the predetermined dynamic pressure and whether the product of the maximum dynamic pressure and the angle of attack is not greater than the predetermined product. If yes, proceed to S114; otherwise, proceed to S116. S114, the initial trajectory inclination angle corresponding to the maximum orbital payload mass is determined as the optimal initial launch inclination angle; S116, For the initial trajectory inclination angles corresponding to the other orbital payload masses besides the maximum orbital payload mass, perform the same judgment as S112 in sequence until the judgment result is yes, then determine the initial trajectory inclination angle corresponding to the judgment result as the optimal initial launch inclination angle. S118, adjust other rocket-related parameters, and return to S102.

2. The method of claim 1, wherein, The method also includes: If the difference between two consecutive calculated objective function output values ​​is not less than a predetermined difference, determine whether the current iteration number is less than the maximum predetermined iteration number. If yes, return to S108; otherwise, end.

3. The method according to claim 2, characterized in that, Determining whether the rocket overload corresponding to each initial trajectory inclination angle satisfies the overload constraint conditions includes: Compare the rocket's axial overload corresponding to each initial trajectory inclination angle with the predetermined axial overload; Compare the rocket's lateral overload corresponding to each initial trajectory inclination angle with the predetermined lateral overload; If the corresponding rocket axial overload is not greater than the predetermined axial overload and the corresponding rocket lateral overload is not greater than the predetermined lateral overload, then the corresponding rocket overload is determined to meet the overload constraint condition; otherwise, the overload constraint condition is not met.

4. The method according to any one of claims 1-3, characterized in that, The initial trajectory inclination angle ranges from 30° to 90°, with predetermined intervals of 5° or 10°.

5. The method according to any one of claims 1-3, characterized in that, Other rocket-related parameters include the maximum angle of attack of the first stage powered phase, the rate of change of the angle of attack of the first stage powered phase, the maximum angle of attack of the second stage powered phase, the rate of change of the angle of attack of the second stage powered phase, the maximum angle of attack of the third stage powered phase, the rate of change of the angle of attack of the third stage powered phase, and the glide time.

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