Carrier rocket safety margin design method and system based on probability calculation and processor

Abstract

The invention provides a carrier rocket safety margin design method and system based on probability calculation and a processor. According to the invention, through probability statistical calculation, a forward numerical design method for directly solving the safety margin based on the known depletion shutdown / injection probability is realized. The method does not depend on accumulation of historical design experience, the safety margin can be directly obtained through modeling calculation, and therefore the method is especially suitable for research and development of brand new rockets lacking reference models. According to the method, by adopting the forward design, the selection of the traditional'safety margin cluster 'and a large amount of random targeting iteration are fundamentally avoided, so that the design period is remarkably shortened, and the design efficiency is improved. The method provided by the invention has been successfully applied to the safety margin design of various models of carrier rockets, and multiple simulation results and flight test data prove the effectiveness of the method.

Description

Technical Field

[0001] This invention relates to the field of aerospace launch vehicle technology, and in particular to a launch vehicle safety margin design method, system and processor based on probabilistic calculation. Background Technology

[0002] Launch capacity is the core optimization objective of rocket overall design. To achieve this objective, liquid-propellant launch vehicles must, in their ballistic trajectory design, reserve a certain safety margin for critical resources such as propellant. This is to overcome the impact of various random performance deviations during flight, ensure that each stage can shut down normally according to guidance commands, and ultimately meet the design requirements for mission reliability and orbital insertion probability. Therefore, a reasonable safety margin design is of paramount importance for ensuring mission success and optimizing overall rocket performance under complex deviation conditions.

[0003] Currently, the common design approach in this field often employs a "reverse" verification model: first, a series of safety margin configuration schemes are pre-set based on engineering experience, forming a so-called "safety margin cluster"; then, each configuration is randomly tested through large-scale simulation calculations (such as the Monte Carlo method) to evaluate its probability of meeting exhaustion shutdown or precise orbit insertion; finally, the scheme that meets the mission reliability requirements and has a relatively small impact on carrying capacity is selected. This method essentially approximates a better solution through traversal and selection.

[0004] However, the above-mentioned approaches face several prominent challenges in practical engineering applications. First, the construction of the initial safety margin cluster largely depends on the prior experience of the designers. The coverage and representativeness of different schemes directly affect the rationality of the optimization results, and there is a lack of a systematic forward derivation mechanism. Second, in order to accurately evaluate the task success rate corresponding to each scheme, massive random simulations must be performed, resulting in a huge computational load. At the same time, the iterative adjustment of the scheme is often accompanied by cumbersome data interaction and repeated verification, making the entire design process cycle long and inefficient.

[0005] Existing safety margin design methods still have room for improvement when addressing the demands of efficient and refined overall design. Therefore, there is an urgent need to provide a forward or systematic design method that can reduce reliance on empirical presuppositions, lower simulation computational complexity, and shorten design iteration cycles, thereby more effectively optimizing the overall performance of launch vehicles while ensuring mission reliability. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a launch vehicle safety margin design method, system, and processor based on probabilistic calculation. Through probabilistic statistical calculation, a forward numerical design method is realized that directly solves for the safety margin when the exhaustion shutdown / orbit insertion probability is known.

[0007] This invention provides a method for designing the safety margin of a launch vehicle based on probabilistic calculations, comprising at least the following steps:

[0008] Step 1: Confirm the initial calculation parameters of the rocket and their deviations, preset the first-stage exhaustion shutdown probability and the second-stage orbital insertion probability, design the initial reference trajectory based on the above parameters, and build a high-fidelity simulation model including closed-loop control based on the reference trajectory and initial parameters.

[0009] Step 2: Introduce shutdown equations and guidance laws into the simulation model, perform controlled zero-interference ballistic simulation, and calculate the existing safety margins of each stage of the rocket.

[0010] Step 3: After introducing various errors into the simulation model, perform single-item deviation simulation, calculate the ballistic margin deviation of each stage of the rocket's oxygen tank and fuel tank, and then perform mean square synthesis to obtain the synthesis result.

[0011] Step 4: Based on the preset first-level exhaustion shutdown probability, second-level orbital insertion probability, and the composite result obtained in Step 3, calculate the required safety margin, and redesign the trajectory based on the calculated required safety margin.

[0012] Step 5: Introduce the shutdown equation and guidance law into the simulation model again to conduct a new round of controlled zero-interference ballistic simulation.

[0013] Step 6: Generate random biases including method error, tool error and unguided error based on statistical laws, perform Monte Carlo random target simulation, and statistically analyze the first-stage exhaustion shutdown probability, impact area range and second-stage orbital insertion probability in the simulation results.

[0014] Step 7: Determine whether the first-stage exhaustion shutdown probability, landing area range, and second-stage orbital insertion probability statistically obtained in Step 6 meet the design requirements. If they meet the design requirements, output the final safety margin design result. Otherwise, iteratively adjust the preset exhaustion shutdown probability and orbital insertion probability of each stage of the rocket, and return to Step 4. Repeat this process until the first-stage exhaustion shutdown probability, landing area range, and second-stage orbital insertion probability statistically obtained in Step 6 all meet the design requirements, and finally output the safety margin result.

[0015] Further, in step four, the method for calculating the required safety margin miu1y of the first-stage oxygen tank is as follows: based on the characteristics of normal distribution, the existing safety margin of the rocket's first-stage oxygen tank in step two is taken as the mean of the normal distribution and is denoted as miu1y; the synthesized result in step three is three times the standard deviation of the normal distribution of the safety margin and is denoted as 3sigma1y; the required safety margin miu1y of the first-stage oxygen tank is solved by the formula: P(X1y<0)=P(Z1y<-miu1y / sigma1y)=preset first-stage oxygen tank depletion shutdown probability; where X1y is the remaining mass of propellant in the first-stage oxygen tank, and after X1y is converted to the standard normal distribution form, Z1y=(X1y-miu1y) / sigma1y is obtained, and the depletion shutdown probability P(X1y<0) is simultaneously converted to P(Z1y<-miu1y / sigma1y).

[0016] In the above embodiments, the solution method for the safety margin miu1y of the primary oxygen chamber includes, but is not limited to: high-precision calculation by reverse lookup table (standard normal distribution table Z-table) or numerical method, and calculation by relevant functions in numerical calculation software.

[0017] Furthermore, step six, generating random biases including method error, tool error, and unguided error based on statistical laws, performing Monte Carlo random target simulation, and statistically analyzing the first-stage exhaustion shutdown probability, impact area range, and second-stage orbital insertion probability in the simulation results, further includes: calculating the first-stage oxygen tank exhaustion shutdown probability P (X1y<0) based on the normal distribution mean miu1y and standard deviation 3sigma1y, and then using:

[0018] P(X1y<0)=P(Z1y<-miu1y / sigma1y), and the probability of the primary oxygen tank running out of oxygen and shutting down is obtained by solving the problem.

[0019] Furthermore, the solution to the probability P (X1y<0) of the primary oxygen tank being depleted and shutting down can be made by means of, but is not limited to, high-precision calculation through reverse lookup table (standard normal distribution table Z-table) or numerical methods, or by calculation using relevant functions in numerical calculation software.

[0020] In any of the above embodiments, the various errors introduced into the simulation model in step three include, but are not limited to, method errors, tool errors, and other non-guided errors.

[0021] In one embodiment, if the rocket is a multi-stage rocket, the exhaustion shutdown probability and orbital insertion probability of each stage are preset according to the number of rocket stages.

[0022] In the above embodiments, the launch vehicle safety margin design method includes performing the design steps as described in any one of claims 1-6 for each propellant tank of each stage of the rocket.

[0023] Another aspect of the present invention provides a launch vehicle safety margin design system based on probability calculation, used to execute the launch vehicle safety margin design method described in any of the above embodiments. The safety margin design system of the present invention includes at least: an initial parameter preset module, a simulation calculation module, a trajectory adjustment module, a random target simulation module, a result judgment module, and an iterative adjustment module;

[0024] The initial parameter preset module is used to confirm the initial calculation parameters of the rocket and their deviations, preset the first-stage exhaustion shutdown probability and the second-stage orbital insertion probability, and design the initial reference trajectory based on the above parameters.

[0025] The simulation calculation module is used to construct a high-fidelity simulation model including closed-loop control based on the reference trajectory and initial parameters. It introduces shutdown equations and guidance laws into the simulation model to perform controlled zero-interference trajectory simulation. After introducing various errors into the simulation model, it performs single-item deviation simulation and calculates the trajectory margin deviations of the rocket's oxygen and fuel tanks at each stage before performing mean-square synthesis. It is also used to calculate the required safety margin based on the preset parameters of the initial parameter preset module and the mean-square synthesis structure.

[0026] The ballistic adjustment module is used to redesign the ballistics based on the required safety margin calculated by the simulation and transmit it to the simulation calculation module;

[0027] The random target simulation module is used to generate random deviations including method error, tool error and unguided error based on statistical laws, to perform Monte Carlo random target simulation, and output the first-level exhaustion shutdown probability, the impact area range and the second-level orbital insertion probability.

[0028] The result judgment module is used to determine whether the first-level exhaustion shutdown probability, landing area range, and second-level orbital insertion probability output by the random target simulation module meet the design requirements, and generate corresponding judgment instructions.

[0029] The iterative adjustment module is connected to the result judgment module and the simulation calculation module. When a judgment instruction indicating that the design requirements are not met is received, the module automatically adjusts the pre-set exhaustion shutdown probability and orbit insertion probability of each stage of the rocket and feeds back the adjusted parameters to the simulation calculation module to start a new round of simulation. The iterative adjustment process continues until the judgment instruction generated by the result judgment module indicates that the design requirements are met.

[0030] The present invention also provides a processor for running a computer program, which, when running, executes the launch vehicle safety margin design method described in any of the above embodiments.

[0031] The present invention provides a method, system, and processor for designing the safety margin of a launch vehicle based on probabilistic calculation, which has at least one of the following beneficial effects:

[0032] I. This invention presents a forward numerical design method for directly calculating the safety margin using probabilistic statistical calculations and given the exhaustion shutdown / orbit insertion probability. The rationality of the design is confirmed through ballistic guidance-based target simulation. Based on known rocket characteristics and deviation parameters, the required safety margin can be directly calculated by establishing a model and running simulations. This method does not require selecting a safety margin cluster and does not rely on past design experience, making it particularly suitable for the development of entirely new rockets lacking reference models.

[0033] Second, by employing forward design, this invention fundamentally avoids the selection of traditional "safety margin clusters" and the need for numerous random target iterations, thereby significantly shortening the design cycle and improving design efficiency. The method provided by this patent has been successfully applied to the safety margin design of various types of launch vehicles. Multiple simulation results and flight test data have confirmed the effectiveness of the method of this invention.

[0034] Third, this patent protects the entire forward design process from "parameter setting → baseline ballistic simulation → deviation synthesis → probability calculation / reverse calculation → ballistic update → target firing verification". This process closely integrates probabilistic statistical models with ballistic guidance simulation, forming a complete technical closed loop of "forward design, quantitative calculation, and target firing verification", ensuring the correctness and reliability of the design results.

[0035] Fourth, the technical solution of this patent has strong extensibility and flexibility. The safety margin forward design method of this embodiment can be extended to specific implementation forms, including but not limited to: applying it to the safety margin design of three-stage and above multi-stage rockets.

[0036] Upon reading the detailed embodiments and examining the accompanying drawings, those skilled in the art will recognize additional features and advantages. Attached Figure Description

[0037] 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.

[0038] Figure 1This is a schematic diagram of the process steps of the launch vehicle safety margin design method based on probability calculation according to an embodiment of the present invention.

[0039] Figure 2 This is a schematic diagram illustrating the calculation of the safety margin in an embodiment of the present invention.

[0040] Figure 3 This is a schematic diagram of the safety margin calculation and shutdown probability verification process according to an embodiment of the present invention.

[0041] Figure 4 This is a flowchart illustrating the safety margin of a launch vehicle based on probability calculation, according to an embodiment of the present invention. Detailed Implementation

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] See Figure 1 This invention provides a method for designing the safety margin of a launch vehicle based on probabilistic calculation, which includes at least the following steps:

[0048] S1. Confirm the initial calculation parameters of the rocket and their deviations, preset the first-stage exhaustion shutdown probability and the second-stage orbital insertion probability, design the initial reference trajectory based on the above parameters, and build a high-fidelity simulation model including closed-loop control based on the reference trajectory and initial parameters.

[0049] S2. Introduce shutdown equations and guidance laws into the simulation model to perform controlled zero-interference ballistic simulation and calculate the existing safety margins of each stage of the rocket.

[0050] S3. After introducing various errors into the simulation model, perform single-item deviation simulation, calculate the ballistic margin deviation of each stage of the rocket's oxygen tank and fuel tank, and then perform mean square synthesis to obtain the synthesis result.

[0051] S4. Based on the preset first-level exhaustion shutdown probability, second-level orbital insertion probability, and the composite result calculated in S3, calculate the required safety margin, and redesign the trajectory based on the calculated required safety margin.

[0052] S5. Introduce the shutdown equation and guidance law again into the simulation model to conduct a new round of controlled zero-interference ballistic simulation.

[0053] S6. Generate random deviations including method error, tool error and unguided error based on statistical laws, perform Monte Carlo random target simulation, and statistically analyze the first-stage exhaustion shutdown probability, impact area range and second-stage orbital insertion probability in the simulation results.

[0054] S7. Determine whether the first-stage exhaustion shutdown probability, landing area range, and second-stage orbit insertion probability statistically obtained in S6 meet the design requirements. If they meet the design requirements, output the final safety margin design result. Otherwise, iteratively adjust the preset exhaustion shutdown probability and orbit insertion probability of each stage of the rocket, and return to S4. Repeat this process until the first-stage exhaustion shutdown probability, landing area range, and second-stage orbit insertion probability statistically obtained in S6 all meet the design requirements, and finally output the safety margin result.

[0055] This embodiment of the probabilistic calculation-based launch vehicle safety margin design method uses known system-level indicators (such as exhaustion shutdown probability and orbital insertion probability) to directly solve for the forward values ​​of safety margins at each stage through probabilistic statistical calculations. The core of this method lies in using probability as the input condition for the design, thus breaking away from the traditional reverse design cycle of "first setting the margin cluster, then verifying the probability." A key advantage of this forward design method for rocket safety margins at each stage is that, since there is no need to pre-select safety margin clusters and the safety margins are directly obtained through modeling calculations, this method reduces its reliance on design experience from historical models, making it particularly suitable for newly developed rockets lacking reference benchmarks.

[0056] Figure 2 The diagram illustrates the statistical relationship between safety margin and the probability of shutdown due to exhaustion. Its core principle can be summarized as follows:

[0057] Assume that all deviations of the rocket follow a normal distribution. After introducing the shutdown equation and guidance law and performing controlled zero-interference ballistic simulation, the safety margins of each stage and each chamber of the rocket constitute the mean of this normal distribution, denoted as miu.

[0058] Method errors, tooling errors, and other unguided errors are introduced into the simulation to perform single-item deviation simulation. The deviations between the remaining mass in each stage of the ballistic chamber and the remaining mass in each stage of the controlled zero-interference trajectory are calculated, and the deviation results are synthesized using mean square. Based on the normal distribution characteristics, this synthesized result is three standard deviations of the safety margin normal distribution, denoted as 3sigma.

[0059] like Figure 2 As shown, when the mass in the tank is less than zero, it indicates that the propellant is exhausted. Taking the first-stage oxygen tank as an example, its exhaustion shutdown probability can be expressed as P(X1y<0). For ease of calculation, the variables are converted to a standard normal distribution (mean 0, variance 1). Let Z1y=(X1y-miu1y) / sigma1y, then the above exhaustion shutdown probability can be converted to P(Z1y<-miu1y / sigma1y). By consulting the standard normal distribution table, the corresponding exhaustion shutdown probability can be determined.

[0060] Specifically, in S4 of the above embodiment, the method for calculating the required safety margin miu1y of the first-stage oxygen tank is as follows: based on the normal distribution characteristics, the existing safety margin of the rocket's first-stage oxygen tank in S2 is taken as the mean of the normal distribution and denoted as miu1y; the synthesized result in S3 is three times the standard deviation of the normal distribution of the safety margin and denoted as 3sigma1y. Specifically, the required safety margin miu1y of the first-stage oxygen tank can be solved by the formula: P(X1y<0)=P(Z1y<-miu1y / sigma1y)=preset first-stage oxygen tank depletion shutdown probability. Wherein, X1y is the remaining mass of propellant in the first-stage oxygen tank. For ease of calculation, X1y is converted into a standard normal distribution form (mean is 0, variance is 1) to obtain Z1y=(X1y-miu1y) / sigma1y. Then, the depletion shutdown probability P(X1y<0) can be simultaneously converted to P(Z1y<-miu1y / sigma1y). The corresponding probability of depletion shutdown can be determined by consulting the standard normal distribution table.

[0061] Furthermore, the solution for the safety margin miu1y of the primary oxygen chamber can be obtained through various methods, including but not limited to: high-precision calculations using reverse lookup tables (standard normal distribution table Z-table) or numerical methods, as well as calculations using relevant functions in numerical calculation software.

[0062] Furthermore, S6, based on statistical laws, generates random biases including method error, tool error, and unguided error, performs Monte Carlo random target simulation, and statistically analyzes the first-stage exhaustion shutdown probability, impact area range, and second-stage orbital insertion probability in the simulation results. It also includes: calculating the first-stage oxygen tank exhaustion shutdown probability P (X1y<0) based on the normal distribution mean miu1y and standard deviation 3sigma1y, and then using:

[0063] P(X1y<0)=P(Z1y<-miu1y / sigma1y), and the probability of the primary oxygen tank running out of oxygen and shutting down is obtained by solving the problem.

[0064] The solution to the probability P (X1y<0) of the primary oxygen tank being depleted and shut down can be obtained by means of reverse lookup (standard normal distribution table Z-table) or high-precision calculation using numerical methods, or by using relevant functions in numerical calculation software.

[0065] It should be noted that, in the above embodiments, the various errors introduced into the simulation model in S3 include, but are not limited to, method errors, tool errors, and other non-guided errors.

[0066] Furthermore, this solution uses a two-stage rocket as an example to illustrate a specific method for calculating the safety margins of the first and second stages of a rocket based on the probability of exhaustion shutdown and the probability of orbital insertion. However, it should be understood that this method is also applicable to multi-stage rockets with three or more stages, and such extended applications are all within the scope of this patent. If the newly developed rocket is a multi-stage rocket, the exhaustion shutdown probability and orbital insertion probability of each stage are preset according to the number of rocket stages, and safety margins are designed. For example, the design steps described in any of the above embodiments are performed for each propellant tank of each stage of the rocket.

[0067] Secondly, the technical solution of this patent embodiment is illustrated using the example of a deviation following a normal distribution, but the method described in this invention is also applicable to other probability distribution forms. For example, it is applicable to other probability distribution models that are not normally distributed, and can be solved through corresponding mathematical transformations and numerical methods.

[0068] Based on the same inventive concept, the derivation of corresponding mathematical formulas for other distributions and the use of numerical methods to solve them should all be considered as a natural extension of the rights of this patent.

[0069] See Figure 3 In any of the above embodiments, to verify the correctness of calculating the exhaustion shutdown probability using the formula, the calculation result can be compared with the Monte Carlo shooting results. Combined with... Figure 3 Taking the depletion shutdown probability of the first-stage oxygen tank of a certain type of liquid oxygen-methane rocket as an example, the specific verification method is as follows:

[0070] Sp1. Confirm the initial calculation parameters and related deviations, and design the initial reference trajectory accordingly.

[0071] Sp2. Introduce shutdown equations and guidance laws into the model to perform controlled zero-interference ballistic simulation.

[0072] Sp3. Calculate the existing safety margin at each level as the mean of the normal distribution, miu. Specifically, miu1y = 789 kg.

[0073] Sp4. In the simulation, add method error, tool error and unguided error, and perform single-item deviation simulation respectively.

[0074] Sp5. For the simulation results of individual deviations, calculate the deviation between each individual deviation simulation result and the remaining mass of the first-stage oxygen tank in the controlled zero-interference trajectory, and perform root mean square synthesis on each deviation result. For the normal distribution deviation, the synthesized result is three times the standard deviation of the safety margin distribution, denoted as 3sigma, and the calculated value is 3sigma1y = 1100kg.

[0075] Sp6. Calculate the probability of shutdown due to exhaustion based on the mean and standard deviation:

[0076] P(X1y<0)=P(Z1y<-miu1y / sigma1y)=P(Z1y<-789*3 / 1100), for the standard normal distribution, its probability density function expression is:

[0077]

[0078] Although the elementary analytical expression for the cumulative probability of the standard normal distribution is not convenient for direct numerical calculation, the probability value of 1.57% can be calculated by using a more efficient and accurate table lookup method (the standard normal distribution Z-table) or the software's built-in optimized numerical algorithm.

[0079] Sp7. Simultaneously, based on statistical laws, random deviation samples containing method error, tool error, and unguided error are generated, and 10,000 Monte Carlo random target simulations are performed.

[0080] Sp8. Count the number of times the primary oxygen tank is depleted and shuts down. According to the target simulation results, the number of times the primary oxygen tank is depleted and shuts down is 152, corresponding to a probability of 1.52%.

[0081] Sp9, comparing the calculated probability (1.57%) with the statistical probability of hitting the target (1.52%), the two are in good agreement, verifying the correctness of the design method.

[0082] Based on the above principles and verification process, combined with Figure 4 Taking the probability of shutdown due to exhaustion of the first-stage oxygen tank of a certain type of liquid oxygen-methane rocket as an example, the specific implementation steps of the forward numerical design method proposed in this invention are illustrated:

[0083] S10. Determine the initial calculation parameters and related deviations; set the allowable exhaustion shutdown probability (e.g., the first-stage oxygen tank exhaustion shutdown probability is 2%) and orbital insertion probability, and design the initial reference trajectory and simulation model.

[0084] S20. Introduce shutdown equations and guidance laws into the model to perform controlled zero-interference ballistic simulation.

[0085] S30. Calculate the existing safety margin for each stage of propellant.

[0086] S40. Incorporate method error, tool error, and unguided error into the simulation to perform single-item deviation simulation.

[0087] S50. For the simulation results of individual deviations, calculate the deviation between each individual deviation simulation result and the remaining mass of the first-stage oxygen tank in a controlled, zero-interference trajectory, and perform root mean square synthesis on each deviation result. For normally distributed deviations, this synthesized result is three times the standard deviation of the safety margin distribution, denoted as 3sigma. The calculation yields 3sigma1y = 1100 kg.

[0088] S60. Based on the set probability requirements at each level and the standard deviation obtained in step S5, calculate the required safety margin. Mathematically, this problem is expressed as: Given P(X1y<0) = P(Z1y<-miu1y / sigma1y) = 2%, solve for miu1y;

[0089] While this problem is difficult to analyze, it can be calculated with high precision using a reverse lookup table (standard normal distribution Z-table) or numerical methods. This patent uses self-developed industrial computing software to calculate this problem. Those skilled in the art can use relevant functions in tools such as MATLAB and Python to calculate the required safety margin for the primary oxygen tank. After looking up the table or calculation, the required safety margin for the primary oxygen tank is obtained as miu1y = 753 kg.

[0090] S70. Based on the calculated safety margin, redesign the trajectory;

[0091] S80, once again introduces shutdown equations and guidance laws, and performs a new round of controlled zero-interference ballistic simulation;

[0092] S90. Generate random deviation samples containing method error, tool error and unguided error based on statistical laws, and perform Monte Carlo random target simulation.

[0093] S100, Statistical analysis of the probability of primary oxygen tank depletion and shutdown, landing area range, and probability of secondary orbit insertion;

[0094] S110. Determine whether the above-mentioned exhaustion shutdown probability, landing area range and orbit insertion probability meet the design requirements.

[0095] S120. If the requirements are met, output the final safety margin design result.

[0096] S130. If the requirements are not met, iteratively adjust the probabilities of each level of requirements, return to step S60 to recalculate the required safety margin based on the updated probabilities and standard deviations, until all indicators meet the requirements, and finally output the safety margin result.

[0097] The design method of this patented embodiment replaces a large number of Monte Carlo shooting iterations with probabilistic calculations to determine the initial value of the safety margin in the design process. This significantly reduces the number of repetitive simulations required to determine the safety margin, fundamentally solving the problems of "large computational load and long design cycle" caused by "random shooting" in traditional methods.

[0098] This process protects the entire forward design flow, from parameter setting to baseline ballistic simulation, deviation synthesis, probability calculation / reverse calculation, ballistic update, and live-fire verification. This flow tightly integrates probabilistic statistical models with ballistic guidance simulation, forming a complete technical closed loop of "forward design, quantitative calculation, and live-fire verification," ensuring the correctness and reliability of the design results.

[0099] In another aspect, the present invention provides a launch vehicle safety margin design system based on probabilistic calculation, used to execute the launch vehicle safety margin design method in any of the above embodiments. The launch vehicle safety margin design system based on probabilistic calculation in this embodiment includes at least an initial parameter preset module, a simulation calculation module, a trajectory adjustment module, a random target simulation module, a result judgment module, and an iterative adjustment module.

[0100] The initial parameter preset module is used to confirm the initial calculation parameters of the rocket and their deviations, preset the first-stage exhaustion shutdown probability and the second-stage orbital insertion probability, and design the initial reference trajectory based on the above parameters.

[0101] The simulation calculation module is used to construct a high-fidelity simulation model including closed-loop control based on the baseline trajectory and initial parameters. Shutdown equations and guidance laws are introduced into the simulation model to perform controlled, zero-interference trajectory simulation. Various errors are introduced into the simulation model to perform single-term deviation simulation, and the trajectory margin deviations of the rocket's oxygen and fuel tanks at each stage are calculated and then subjected to mean-square synthesis. Additionally, it is used to calculate the required safety margin based on the preset parameters of the initial parameter preset module and the mean-square synthesis structure.

[0102] The ballistic adjustment module is used to redesign the trajectory based on the required safety margin calculated by simulation and transmit it to the simulation calculation module.

[0103] The random target simulation module is used to generate random deviations, including method error, tool error and unguided error, based on statistical laws, to perform Monte Carlo random target simulation, and output the first-level exhaustion shutdown probability, the impact area range and the second-level orbital insertion probability.

[0104] The result judgment module is used to determine whether the first-level exhaustion shutdown probability, landing area range, and second-level orbital insertion probability output by the random target simulation module meet the design requirements, and to generate corresponding judgment instructions.

[0105] The iterative adjustment module is connected to both the result judgment module and the simulation calculation module. Upon receiving a judgment command indicating that the design requirements are not met, it automatically adjusts the pre-set exhaustion shutdown probability and orbital insertion probability for each stage of the rocket and feeds the adjusted parameters back to the simulation calculation module to initiate a new round of simulation. The iterative adjustment process continues until a judgment command generated by the result judgment module indicates that the design requirements are met.

[0106] The present invention also provides a processor for running a computer program, which executes the launch vehicle safety margin design method in any of the above embodiments when the computer program is running.

[0107] It should be noted that the shutdown equations and guidance law designs involved in the embodiments of the present invention are based on the theoretical foundation and general methods of my country's aerospace industry standard "QJ 20313-2014 Design Guidelines for Missile and Launch Vehicle Guidance Systems". The core ideas can also be found in the classic work of control theory "Control Systems (Part 1)" (often referred to in the industry as the "Red Book").

[0108] The above embodiments can be combined with each other and have corresponding technical effects.

[0109] 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. A method for designing the safety margin of a launch vehicle based on probabilistic calculation, characterized in that, At least the following steps are included: Step 1: Confirm the initial calculation parameters of the rocket and their deviations, preset the first-stage exhaustion shutdown probability and the second-stage orbital insertion probability, design the initial reference trajectory based on the above parameters, and build a high-fidelity simulation model including closed-loop control based on the reference trajectory and initial parameters. Step 2: Introduce shutdown equations and guidance laws into the simulation model, perform controlled zero-interference ballistic simulation, and calculate the existing safety margins of each stage of the rocket. Step 3: After introducing various errors into the simulation model, perform single-item deviation simulation, calculate the ballistic margin deviation of each stage of the rocket's oxygen tank and fuel tank, and then perform mean square synthesis to obtain the synthesis result. Step 4: Based on the preset first-level exhaustion shutdown probability, second-level orbital insertion probability, and the composite result obtained in Step 3, calculate the required safety margin, and redesign the trajectory based on the calculated required safety margin. Step 5: Introduce the shutdown equation and guidance law into the simulation model again to conduct a new round of controlled zero-interference ballistic simulation. Step 6: Generate random biases including method error, tool error and unguided error based on statistical laws, perform Monte Carlo random target simulation, and statistically analyze the first-stage exhaustion shutdown probability, impact area range and second-stage orbital insertion probability in the simulation results. Step 7: Determine whether the first-stage exhaustion shutdown probability, landing area range, and second-stage orbital insertion probability statistically obtained in Step 6 meet the design requirements. If they meet the design requirements, output the final safety margin design result. Otherwise, iteratively adjust the preset exhaustion shutdown probability and orbital insertion probability of each stage of the rocket, and return to Step 4. Repeat this process until the first-stage exhaustion shutdown probability, landing area range, and second-stage orbital insertion probability statistically obtained in Step 6 all meet the design requirements, and finally output the safety margin result.

2. The launch vehicle safety margin design method based on probability calculation according to claim 1, characterized in that, In step four, the method for calculating the required safety margin miu1y for the primary oxygen tank is as follows: Based on the characteristics of normal distribution, the existing safety margin of the rocket's first-stage oxygen tank in step two is taken as the mean of the normal distribution and is denoted as miu1y; the synthesized result in step three is three standard deviations of the normal distribution of the safety margin and is denoted as 3sigma1y. The required safety margin miu1y for the primary oxygen tank can be calculated using the formula: P(X1y<0)=P(Z1y<-miu1y / sigma1y)=preset probability of primary oxygen tank running out of oxygen tank. Where X1y is the remaining mass of propellant in the first-stage oxygen tank, X1y is transformed into a standard normal distribution form to obtain Z1y=(X1y-miu1y) / sigma1y, and the exhaustion shutdown probability P(X1y<0) is simultaneously transformed into P(Z1y<-miu1y / sigma1y).

3. The launch vehicle safety margin design method based on probabilistic calculation according to claim 2, characterized in that, The solution for the safety margin miu1y of the primary oxygen chamber includes, but is not limited to: high-precision calculation by reverse lookup table (standard normal distribution table Z-table) or numerical method, and calculation by relevant functions in numerical calculation software.

4. The launch vehicle safety margin design method based on probabilistic calculation according to claim 3, characterized in that, Step six, which generates random biases including method error, tool error, and unguided error based on statistical laws, performs Monte Carlo random target simulation, and statistically analyzes the first-stage exhaustion shutdown probability, impact area range, and second-stage orbital insertion probability in the simulation results, further includes: The probability of primary oxygen tank depletion shutdown, P(X1y<0), is calculated based on the normal distribution mean miu1y and standard deviation 3sigma1y. This is achieved through: P(X1y<0)=P(Z1y<-miu1y / sigma1y), and the probability of the primary oxygen tank running out of oxygen and shutting down is obtained by solving the problem.

5. The launch vehicle safety margin design method based on probabilistic calculation according to claim 4, characterized in that, The solution to the probability P (X1y<0) of the primary oxygen tank being depleted and shutting down can be obtained by, but is not limited to, high-precision calculation through reverse lookup (standard normal distribution table Z-table) or numerical methods, or by calculation using relevant functions in numerical calculation software.

6. The method for designing the safety margin of a launch vehicle based on probabilistic calculation according to any one of claims 1 to 5, characterized in that, In step three, the various errors introduced into the simulation model include, but are not limited to, method errors, tool errors, and other non-guided errors.

7. The launch vehicle safety margin design method based on probabilistic calculation according to claim 1, characterized in that, If the rocket is a multi-stage rocket, the probability of exhaustion and shutdown of each stage and the probability of entering orbit are preset according to the number of rocket stages.

8. The launch vehicle safety margin design method based on probabilistic calculation according to claim 7, characterized in that, The launch vehicle safety margin design method includes performing the design steps as described in any one of claims 1-6 for each propellant tank of each stage of the rocket.

9. A launch vehicle safety margin design system based on probabilistic calculation, used to execute the launch vehicle safety margin design method as described in any one of claims 1-8, characterized in that, At least including: The initial parameter preset module is used to confirm the initial calculation parameters of the rocket and their deviations, preset the first-stage exhaustion shutdown probability and the second-stage orbital insertion probability, and design the initial reference trajectory based on the above parameters; The simulation calculation module is used to build a high-fidelity simulation model with closed-loop control based on the reference trajectory and initial parameters. The shutdown equation and guidance law are introduced into the simulation model to perform controlled zero-disturbance trajectory simulation. After introducing various errors into the simulation model, single-item deviation simulation was performed, and mean square synthesis was performed after calculating the ballistic margin deviations of the oxygen tanks and fuel tanks of each stage of the rocket. And, for calculating the required safety margin based on the preset parameters of the initial parameter preset module and the mean square synthesis result; The ballistic adjustment module is used to redesign the ballistics based on the required safety margin calculated by the simulation and transmit it to the simulation calculation module; The random target simulation module is used to generate random deviations including method error, tool error and unguided error based on statistical laws, to perform Monte Carlo random target simulation, and output the first-level exhaustion shutdown probability, the impact area range and the second-level orbital insertion probability. The result judgment module is used to judge whether the first-level exhaustion shutdown probability, landing area range and second-level orbital insertion probability output by the random target simulation module meet the design requirements, and generate corresponding judgment instructions. The iterative adjustment module, connected to the result judgment module and the simulation calculation module, is used to automatically adjust the preset exhaustion shutdown probability and orbit insertion probability of each stage of the rocket when a judgment instruction indicating that the design requirements are not met is received, and feeds back the adjusted parameters to the simulation calculation module to start a new round of simulation; the iterative adjustment process continues until the judgment instruction generated by the result judgment module indicates that the design requirements are met.

10. A processor, characterized in that, Used to run a computer program, which executes the launch vehicle safety margin design method according to any one of claims 1-8.

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