A probabilistic load design method for aerospace vehicles

Abstract

The application provides a kind of probability load design method of space vehicle, comprising: step one, collect the historical measured high altitude wind data of single wind field as input, generate quasi-real-time wind correction trajectory according to wind data;Step two, obtain active load shedding control law by using active load shedding control scheme based on acceleration feedback;Step three, carry out six-degree-of-freedom Monte Carlo shooting flight simulation based on quasi-real-time wind correction trajectory, add active load shedding control law in simulation, calculate the static load of each section of space vehicle corresponding to each second point, obtain the axial force, shear force and bending moment load of each station;Step four, map the static load to several space vehicle flight altitude layers, count the load probability distribution under different flight altitudes, and obtain the load envelope of each station along the axial direction of space vehicle under the condition of single wind field. This method realizes multidisciplinary collaborative optimization, reduces design margin while ensuring reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aerospace technology, in particular to a probability load design method of a space carrier. BACKGROUND

[0002] In the prior art, the probability load of a space carrier usually adopts statistical high-altitude wind field, and is modeled based on the mean value or extreme value of historical meteorological data, which cannot accurately reflect the complex wind field characteristics such as transient wind shear and turbulence in actual flight, ignores the spatial and temporal randomness of the wind field, overestimates the occurrence probability of extreme load, and leads to conservative design load. Due to insufficient consideration of the randomness of wind field, aerodynamic parameters and control system, the actual occurrence probability of the combination of extreme wind field and maximum attack angle is extremely low, resulting in conservative load design.

[0003] In addition, each specialty works independently and adopts a "tandem" design process, which has professional barriers, leading to error amplification and "margin superposition" effect, and the simulation of aerodynamic, control and structural coupling is not accurate enough. Generally, each specialty will cover uncertainties by increasing the safety factor, resulting in more conservative design of the product.

[0004] Therefore, there is an urgent need to design a probability load design method of a space carrier that considers multi-specialty collaboration and can accurately calculate load. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a probability load design method of a space carrier.

[0006] The present application provides a probability load design method of a space carrier, comprising:

[0007] Step one, collect the historical measured high-altitude wind data of a single wind field as input, and generate a quasi-real-time wind correction trajectory according to the wind data;

[0008] Step two, adopt an active load reduction control scheme based on acceleration feedback to obtain an active load reduction control law and realize effective control of lateral normal acceleration;

[0009] Step three, perform six-degree-of-freedom Monte Carlo targeting flight simulation based on the quasi-real-time wind correction trajectory designed in step one, and add the active load reduction control law designed in step two in the simulation to calculate the static load of each section of the space carrier corresponding to each second point, and obtain the axial force, shear force and bending moment load of each station;

[0010] Step four, mapping the static load of each station point corresponding to each section of the space vehicle obtained in step three to a plurality of space vehicle flight altitude layers according to the relationship between the station point and the flight altitude of the space vehicle during flight, and counting the load probability distribution at different flight altitudes to obtain the load envelope of each station point along the axial direction of the space vehicle under the single wind field condition.

[0011] According to an embodiment of the present application, the step four further comprises: repeating steps one to four for the measured wind field database of multiple wind fields to obtain the corresponding load envelope under all historical measured high-altitude wind field conditions.

[0012] According to an embodiment of the present application, the step one further comprises: solving the ballistic motion equation based on historical measured high-altitude wind data with the minimum aerodynamic attack angle as the target, wherein during the solving of the ballistic motion equation, the longitudinal axis of the space vehicle is made consistent with the airspeed vector in the transonic section and the maximum dynamic pressure zone, while satisfying the entry condition constraint.

[0013] According to an embodiment of the present application, the step two further comprises: adding an acceleration feedback loop to the pitch and yaw channel program angle tracking scheme to form a three-loop control system structure.

[0014] According to an embodiment of the present application, in the step three: the static load comprises the axial load, the aerodynamic load and the control load received by each section of the space vehicle.

[0015] According to an embodiment of the present application, the step four further comprises: for each combination of station point and flight altitude, counting all the load samples calculated under the historical wind field conditions, including the axial force, the shear force and the bending moment load, estimating the load probability distribution of each station point at different flight altitudes, and obtaining the axial force, the shear force and the bending moment probability distribution, and then obtaining the axial force, the shear force and the bending moment satisfying a certain probability according to the probability distribution.

[0016] According to an embodiment of the present application, the step three further comprises: synthesizing the static load with the sway, the gust and the pulsating pressure load to obtain the total load of each station point considering the sway load, the gust load and the pulsating pressure load, i.e. the total axial force, the total shear force, the total bending moment, the equivalent axial tension and the equivalent axial compression.

[0017] In another aspect, the present application further provides an electronic device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the above-mentioned probability load design method of the space vehicle when executing the computer program.

[0018] In still another aspect, the present application also provides a computer readable storage medium, having stored thereon a computer program, which, when executed by a processor, implements the steps of the above-mentioned space vehicle probabilistic load design method.

[0019] The design method of the present embodiment integrates multi-disciplinary technologies such as measured high-altitude wind field data processing, wind-corrected trajectory optimization design, six-degree-of-freedom dynamics simulation, active load control, and probabilistic statistical analysis, and solves the problem of fine calculation of aerodynamic loads of space vehicles when passing through high-altitude strong wind areas. The wind data of the historical measured high-altitude wind field can accurately reflect the complex wind field characteristics such as transient wind shear and turbulence in actual flight, significantly improving the representation accuracy of wind shear gradient and transient turbulence characteristics.

[0020] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit the scope of the invention claimed. BRIEF DESCRIPTION OF DRAWINGS

[0021] The following drawings are part of the specification of the present application and illustrate example embodiments of the present application, which, together with the description of the specification, serve to explain the principles of the invention.

[0022] Figure 1 is a schematic diagram of a probabilistic load design method of a space vehicle according to an embodiment of the present application;

[0023] Figure 2 is a comparison diagram of a measured wind field and a statistical wind field according to an embodiment of the present application. DETAILED DESCRIPTION

[0024] The features and exemplary embodiments of various aspects of the present application will be described in detail below, in order to make the purposes, technical solutions and advantages of the present application more clear and apparent, the present application will be further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application, for exemplary illustration of the principles of the present application, and are not configured to limit the present application. In addition, the components in the drawings are not necessarily drawn to scale. For example, the size of some components in the drawings can be enlarged relative to other components or regions to help understand the embodiments of the present application.

[0025] The positional words appearing in the following description are the directions shown in the drawings, and are not intended to limit the specific structure of the embodiments of the present application. In the description of the present application, it should be noted that, unless otherwise specified, the terms "mounting", "connection", "connecting" should be interpreted broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0026] In addition, the terms "including", "containing", "having" or any other variants thereof are intended to cover non-exclusive inclusion, so that the inclusion of a series of element structures or components not only includes those elements, but also includes other elements not explicitly listed or inherent in the structure, component. Without more limitation, the elements defined by the sentence "including" do not exclude the presence of additional same elements in the article or device including the elements.

[0027] Spatial relationship terms such as "below", "under", "under", "low", "above", "on", "high" and the like are used to facilitate the description to explain the position of one element relative to the second element, indicating that these terms are intended to cover different orientations of the device in addition to the orientations shown in the drawings. In addition, for example, "one element is on / under another element" can mean that the two elements are in direct contact, or that there are other elements between the two elements. In addition, terms such as "first", "second", etc. are also used to describe various elements, regions, parts, etc., and should not be considered as limiting. Similar terms are used throughout the description to represent similar elements.

[0028] For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0029] Figure 1 The present application provides a spacecraft probabilistic load design method, Figure 2 is a comparison chart of the measured wind field and the statistical wind field in an embodiment of the present application.

[0030] As Figure 1 shown, the present application provides a spacecraft probabilistic load design method, comprising:

[0031] Step one S100, collect the historical measured high-altitude wind data of a single wind field as input, and generate a quasi-real-time wind correction trajectory according to the wind data;

[0032] In step two S200, an active load reduction control scheme based on acceleration feedback is used to obtain an active load reduction control law, so as to realize effective control of lateral normal acceleration.

[0033] In step three S300, six-degree-of-freedom Monte Carlo targeting flight simulation is performed based on the quasi-real-time wind corrected trajectory obtained in step one, and the active load reduction control law designed in step two is added in the simulation, so as to calculate the static load of each section of the space vehicle corresponding to each second point, and obtain the axial force, shear force and bending moment load of each station.

[0034] In step four S400, the static load of each section of the space vehicle corresponding to each second point obtained in step three is mapped to a plurality of space vehicle flight height layers according to the relationship between the second point and the flight height of the space vehicle during flight, so as to statistically obtain the load probability distribution at different flight heights, and obtain the load envelope of each station along the axial direction of the space vehicle under the single wind field.

[0035] According to one embodiment of the present application, after step four, the method further comprises: repeating steps one to four for the measured wind field database of the multi-wind field, so as to obtain the corresponding load envelope under all historical measured high-altitude wind field conditions.

[0036] In the probability load design method of the space vehicle in the embodiment, the wind data of the historical measured high-altitude wind field is used, so as to avoid the uncertainty of using the statistical wind field model and the complexity of predicting and fitting the real wind field in the traditional load design, and improve the accuracy of the wind field representation. Figure 2 As shown in the figure, the rhombus dotted line is the statistical maximum value, the square dotted line is the statistical maximum value of 75%, the triangle dotted line is the statistical maximum value of 50%, the circular dotted line is the statistical maximum value of 25%, and the solid line is the measured wind speed value. It can be seen that the wind direction and wind speed of the measured high-altitude wind field are quite different from those of the statistical wind field model. The measured high-altitude wind field can accurately reflect the complex wind field characteristics such as transient wind shear and turbulence in actual flight, significantly improve the representation accuracy of the wind shear gradient and transient turbulence characteristics, and overcome the inherent limitations of the traditional statistical wind field model in simulating complex meteorological conditions.

[0037] Specifically, in step one, the quasi-real-time trajectory wind correction technology is used. When the space vehicle flies in the large wind area according to the quasi-real-time wind corrected trajectory, the theoretical attack angle is close to 0°, which fundamentally reduces the flight load of the space vehicle. Designing the wind corrected trajectory for each measured high-altitude wind field can effectively reduce the aerodynamic interference and control load, thereby reducing the flight load.

[0038] In step two, the wind-corrected trajectory obtained in step one is applied to the active load alleviation control scheme of step two with acceleration feedback to obtain an active load alleviation control law, which suppresses the lateral normal overload, reduces the aerodynamic disturbance in the strong wind area, and realizes active load alleviation.

[0039] In step three, the quasi-real-time wind-corrected trajectory designed according to the measured wind field is used for six-degree-of-freedom Monte Carlo targeting flight simulation, and the active load alleviation control law is added in the simulation process. The aerodynamic attack angle and engine swing angle of the spacecraft at each second point in each targeting flight simulation are obtained, and after obtaining the flight simulation samples, the static load of each section of the spacecraft corresponding to each second point is calculated to obtain the axial force, shear force, and bending moment load at each station on the spacecraft. In the actual flight of the spacecraft, the quasi-real-time wind-corrected trajectory parameters in step one and the active load alleviation parameters in step two are used.

[0040] In step four, considering the correlation between load and flight altitude, the static load of each section of the spacecraft corresponding to each second point is mapped to a number of flight altitude layers, and the load probability distribution of the spacecraft at different flight altitudes is counted. The load envelope of each station on the spacecraft under a single wind field condition is obtained in this step, i.e., the load probability distribution of each station, which can be used for the design of the spacecraft according to the required load probability output.

[0041] In one embodiment, for launch sites with multiple wind fields, the historical measured high-altitude wind field database is calculated according to steps one to four, and the data of each single wind field is repeated in the above steps to obtain the load envelope under all historical measured wind field conditions. The severity of the wind field is determined by the load index, and the load envelope covering 95% of the wind fields in all historical wind fields is the 95% probability load.

[0042] In this embodiment, the design method integrates trajectory correction, six-degree-of-freedom Monte Carlo simulation, active load alleviation, and probability load calculation technology, overcomes the problem of repeated conservative parameters caused by traditional independent design of each department, and realizes multidisciplinary collaborative optimization. Based on the six-degree-of-freedom Monte Carlo simulation, the probability load envelope is generated, the load distribution characteristics under different meteorological conditions are quantitatively evaluated, the design margin is reduced while ensuring reliability, and the load optimization under strong wind field conditions is more suitable.

[0043] According to one embodiment of the present application, step one further comprises: solving the trajectory equation based on the historical measured high-altitude wind data with the minimum aerodynamic attack angle as the target, wherein in the process of solving the trajectory equation, the longitudinal axis of the space vehicle is aligned with the airspeed vector in the transonic section and the maximum dynamic pressure zone, while satisfying the orbit entry condition constraints.

[0044] According to one embodiment of the present application, step two further comprises: adding an acceleration feedback loop to the pitch and yaw channel program angle tracking scheme to form a three-loop control system structure.

[0045] According to one embodiment of the present application, in step three: the static load includes the axial load, aerodynamic load and control load received by each section of the space vehicle.

[0046] According to one embodiment of the present application, step four further comprises: for each combination of station and flight altitude, statistically analyzing all the load samples calculated under the historical wind field conditions, including the axial force, shear force and bending moment load, to estimate the load probability distribution of each station at different flight altitudes, and obtaining the axial force, shear force and bending moment that meet a certain probability after obtaining the probability distribution of the axial force, shear force and bending moment.

[0047] According to one embodiment of the present application, step three further comprises: synthesizing the static load with the sway, gust and fluctuating pressure load to obtain the total load of each station considering the sway load, gust load and fluctuating pressure load, i.e. the total axial force, total shear force, total bending moment, equivalent axial tension and equivalent axial compression.

[0048] On the other hand, the present application also provides an electronic device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the above-mentioned probability load design method of the space vehicle when executing the computer program.

[0049] Still on the other hand, the present application also provides a computer readable storage medium, which stores a computer program, and the processor implements the steps of the above-mentioned probability load design method of the space vehicle when executing the computer program.

[0050] Specifically, based on the distribution data of the wind speed and direction of the historical measured wind field with the height, the trajectory equation is solved with the minimum aerodynamic attack angle as the target to design the wind-corrected trajectory. The wind-corrected trajectory requires that the longitudinal axis of the space vehicle is aligned with the airspeed vector in the transonic section and the maximum dynamic pressure zone, i.e. the attack angle theoretically approaches 0°, while satisfying the orbit entry condition constraints.

[0051] In high-wind areas, an active load reduction control scheme based on accelerometer feedback is used to develop an active load reduction control law. Based on the program angle tracking scheme for the pitch and yaw channels, an acceleration feedback loop is added to form a three-loop control system structure. Acceleration feedback is used to effectively control the lateral normal acceleration, suppressing the aerodynamic angle of attack and sideslip angle of the space vehicle during flight, reducing the angle of attack and aerodynamic load. As the aerodynamic load decreases, the required engine swing control load also decreases. In the six-degree-of-freedom Monte Carlo target practice flight simulation, a program angle tracking control scheme is used for the pitch, yaw, and roll channels. The outer loop tracks the program angle command signal through attitude angle feedback, while the inner loop improves control system stability through angular velocity feedback.

[0052] It can be understood that the static loads of each section of the space vehicle at each second point include axial load, aerodynamic load, and control load. The axial load is the force along the axis of the space vehicle, the aerodynamic load is the atmospheric force on the space vehicle during flight, and the control load comes from the guidance and attitude control system of the space vehicle. When calculating the load statistics of all wind data samples, for each combination of station and height, the axial force, shear force, and bending moment loads of all wind data samples are statistically analyzed, and their probability distribution is estimated to obtain the mean and satisfaction of the axial force, shear force, and bending moment. deviation.

[0053] As one embodiment, the load also needs to consider dynamic loads, incorporating sway, gust, and fluctuating pressure load data into the load calculation. Sway, gust, and fluctuating pressure load data are pre-calculated by the load specialist. The static load is combined with the sway, gust, and fluctuating pressure loads to obtain the total load for each station, including the total axial force, total shear force, total bending moment, and equivalent axial tension and equivalent axial compression, taking into account sway, gust, and fluctuating pressure loads.

[0054] The load index is used to determine the severity of a wind field. The load envelope covering 95% of all historical wind fields represents the 95% probability load based on the historical high-altitude wind field database. For example, if the historical high-altitude wind field database contains 4,000 wind field data, a 95% probability load envelope means that 5% (approximately 200 wind fields) have loads above the 95% probability load envelope. The 95% probability load envelope is sufficient to cover 3,800 historical high-altitude measured wind fields.

[0055] The probabilistic payload design method for a space vehicle of this embodiment takes into account the coupling relationship between various disciplines, such as the integration of ballistics, aerodynamics, attitude control, and payload, thereby avoiding the problem of margin overlap caused by independent design of each discipline in traditional methods.

[0056] The above merely preferred embodiments of the present application are not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A probabilistic load design method for a space vehicle, characterized in that: include: Step 1: collecting historically measured high-altitude wind data from a single wind field as input, and generating a quasi-real-time wind-corrected trajectory based on the wind data; Step 1 further includes: solving the trajectory motion equation based on the historically measured high-altitude wind data with a minimum aerodynamic angle of attack as a target, wherein, in solving the trajectory motion equation, the longitudinal axis of the space vehicle is aligned with the airspeed vector in the transonic region and the maximum dynamic pressure region, while satisfying orbital insertion constraints; Step 2: adopt an active load reduction control scheme based on acceleration feedback to obtain the active load reduction control law and achieve effective control of the lateral normal acceleration; Step 3: Perform a six-degree-of-freedom Monte Carlo target practice flight simulation based on the quasi-real-time wind-corrected trajectory designed in the measured wind in Step 1. The active load reduction control law designed in Step 2 is incorporated into the simulation to calculate the static loads on each section of the space vehicle at each second, and obtain the axial force, shear force, and bending moment loads at each station. Step 4: Map the static loads of each section of the space vehicle at each second point obtained in step 3 to several flight altitude layers of the space vehicle according to the relationship between the second point and the flight altitude during the flight of the space vehicle, and statistically analyze the load probability distribution at different flight altitudes to obtain the load envelope of each station along the axis of the space vehicle under the single wind field condition, and design the space vehicle according to the load envelope.

2. The probabilistic load design method for a space vehicle according to claim 1, characterized in that: The step 4 further includes: For the measured wind field database of multiple wind fields, repeat steps 1 to 4 to obtain the corresponding load envelopes under all historical measured high-altitude wind field conditions.

3. The probabilistic load design method for a space vehicle according to claim 1, characterized in that: The second step also includes: Based on the program angle tracking scheme of the pitch and yaw channels, an acceleration feedback loop is added to form a three-loop control system structure.

4. The probabilistic load design method for a space vehicle according to claim 1, characterized in that: In step three: The static load includes the axial load, aerodynamic load and control load borne by each section of the space vehicle.

5. The probabilistic load design method for a space vehicle according to claim 4, characterized in that: The step 4 further includes: For each combination of site and flight altitude, the load samples calculated under all historical wind field conditions are used to estimate the load probability distribution of each site at different flight altitudes. After obtaining the probability distribution of axial force, shear force and bending moment, the axial force, shear force and bending moment that meet a certain probability can be obtained based on the probability distribution.

6. The probabilistic load design method for a space vehicle according to claim 5, characterized in that: The step three also includes: The static load is synthesized with the sway, gust, and fluctuating pressure loads to obtain the total load at each site considering the sway load, gust load, and fluctuating pressure load, namely the total axial force, total shear force, total bending moment, equivalent axial tension, and equivalent axial compression.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the probabilistic load design method for a space vehicle according to any one of claims 1 to 6 is implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the probabilistic load design method for a space vehicle according to any one of claims 1 to 6 are implemented.

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