Thrust adjustment guidance method based on speed and overload

Abstract

The invention provides a thrust adjustment guidance method based on speed and overload, and the method comprises the following steps: calculating a standard speed value Vcx corresponding to the standard height of a carrier rocket, an average overload value Acx corresponding to the standard height, a speed adjustment coefficient Kv corresponding to the standard height, an overload adjustment coefficient Ka corresponding to the standard height, a starting adjustment thrust characteristic quantity Wstart, an average speed value Vcx corresponding to the standard height, a speed adjustment coefficient Kv corresponding to the standard height and an overload adjustment characteristic quantity Ka corresponding to the standard height; ending adjustment of the thrust characteristic quantity Wend and the thrust adjustment threshold dAstd, and carrying out data binding on the thrust characteristic quantity Wend and the thrust adjustment threshold dAstd; obtaining overload at the current and preorder flight moments in real time, and carrying out smoothing processing to obtain overload A; the speed of the current flight moment is obtained in real time, and the speed V is obtained; calculating a thrust adjustment coefficient dVA according to the current state: dVA = Kv * (V-Vcx) + Ka * (A-Acx); and the thrust adjustment coefficient of the current state is compared with the thrust adjustment threshold dVAstd, the throttling ratio is calculated, and then thrust adjustment is conducted.

Description

Technical Field

[0001] The present invention relates to the technical field of space launch vehicles, in particular to a thrust adjustment guidance method based on speed and overload. Background Art

[0002] Reusable liquid rockets will be a key research direction for reducing rocket costs and increasing efficiency in the future. Widely adjustable thrust engines are a key technology for achieving low-cost, reusable rockets. Reusable rockets must not only meet payload accuracy requirements but also ensure precise landing of the substage. During recovery, how to adjust thrust to ensure accurate trajectory tracking and ensure high-precision rocket recovery remain pressing challenges.

[0003] In the invention patent CN114109652B "A method and device for regulating thrust of a liquid rocket engine", a fixed proportional coefficient is used to calculate the valve adjustment opening. However, this method cannot take into account the entire flight process, and has limited control over thrust regulation. In addition, the direct use of the overload integral term easily introduces interference noise during the flight, and the interference information is amplified after integration.

[0004] In the invention patent CN112304169B "A launch vehicle guidance method and system based on thrust regulation", calculating the target thrust requires estimating the rocket mass. However, the rocket mass during flight is difficult to estimate accurately, and using only speed to regulate thrust will cause the thrust adjustment result to lag and fail to respond in time.

[0005] Therefore, there is an urgent need to provide a thrust adjustment guidance method with timely response and less interference. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention proposes a thrust adjustment guidance method based on speed and overload, which can accurately adjust the engine thrust during flight, thereby achieving high-precision trajectory tracking of the carrier rocket.

[0007] The present invention provides a thrust adjustment guidance method based on speed and overload, which comprises at least the following steps: Step 1: Bind at least the standard speed value Vcx corresponding to the standard characteristic value of the launch vehicle, the average overload value Acx corresponding to the standard characteristic value, the speed adjustment coefficient Kv corresponding to the standard characteristic value, the overload adjustment coefficient Ka corresponding to the standard characteristic value, the starting adjustment thrust characteristic value Wstart, the ending adjustment thrust characteristic value Wend, and the thrust adjustment threshold dVAstd; Step 2: Determine whether the current characteristic value reaches the starting thrust adjustment characteristic value Wstart. If it does not meet the determination adjustment requirement, enter the next determination cycle for re-determination until the current characteristic value reaches the starting thrust adjustment characteristic value Wstart. Step 3: Get the current speed value V and overload value A; Step 4: Use the standard feature quantity interpolation to feedback the speed adjustment coefficient Kv corresponding to the standard feature quantity, the overload adjustment coefficient Ka corresponding to the standard feature quantity, the theoretical speed Vcx corresponding to the standard feature quantity, and the theoretical apparent acceleration Acx; Step 5. Use the thrust adjustment formula: dVA = Kv × (V-Vcx) + Ka × (A-Acx) to calculate the thrust adjustment coefficient dVA; Step 6: Compare the thrust adjustment coefficient dVA with the thrust adjustment threshold dVAstd to obtain the throttle ratio, and adjust the engine thrust according to the throttle ratio.

[0008] Furthermore, after the thrust adjustment coefficient dVA is calculated using the thrust adjustment formula dVA=Kv×(V-Vcx)+Ka×(A-Acx) described in step five, the process further includes: determining whether the current characteristic quantity reaches the thrust characteristic quantity Wend for ending adjustment; if the determination adjustment is not satisfied, proceeding to the next step; if the determination adjustment is satisfied, ending the thrust adjustment.

[0009] Furthermore, the method for obtaining the current speed value V is to obtain the module value of the flight speed calculated by navigation in the current control cycle, which is specifically calculated by the following formula: ,in They are the speed values ​​in the three directions of the navigation coordinate system.

[0010] Furthermore, the method for obtaining the overload value A is: obtaining an average value of the overload modulus values ​​of the current control cycle and the previous control cycle.

[0011] Furthermore, the method for obtaining the average value of the overload modulus values ​​of the current control cycle and the previous control cycle is: Calculated by the following formula: , ， Where N is the number of control cycles, are the apparent acceleration values ​​in three directions in the rocket body coordinate system.

[0012] Furthermore, in any of the above embodiments, in step 6, the thrust adjustment coefficient dVA is compared with the thrust adjustment threshold dVAstd to obtain the throttle ratio, and the method for adjusting the engine thrust according to the throttle ratio is: Compare the thrust adjustment coefficient with the thrust adjustment threshold dVAstd and calculate the throttling ratio that needs to be adjusted using the following formula: : , Wherein, dVAstd is the thrust adjustment threshold, dtj is the thrust adjustment step size, and dVA is the thrust adjustment coefficient; The current throttling ratio is calculated by the following formula : ,in is the throttling ratio of the previous cycle; According to the current throttling ratio Determine engine thrust and make rapid adjustments to engine thrust in real time.

[0013] Furthermore, the thrust adjustment threshold dVAstd is comprehensively given based on the engine test data and the speed overload data; and the thrust adjustment step dtj is given based on the engine test data.

[0014] Furthermore, the method for determining whether the current characteristic value reaches the thrust characteristic value Wstart for starting to adjust is: determining whether |W-Wstart| < If the judgment result is yes, then proceed directly to the next adjustment step; if the judgment result is no, then enter the next judgment cycle for re-judgment.

[0015] Furthermore, the The value range is 0.01±0.05.

[0016] Furthermore, the control cycle number N ranges from 5 to 100.

[0017] The thrust regulation and guidance method provided by this invention, based on speed and overload, can rapidly adjust thrust in real time based on real-time flight conditions, thereby achieving precise trajectory tracking. This thrust regulation and guidance method, when applied to recoverable rockets, can enable them to precisely return to a landing site. Previously, this thrust regulation and guidance method was successfully applied to the ZQ-3 carrier rocket's vertical takeoff and vertical recovery test rocket.

[0018] The flight overload used in the thrust regulation guidance method based on speed and overload of the present invention is filtered and smoothed, which can effectively prevent interference signals from entering the thrust regulation loop. The overload and speed regulation constitute PD control, which greatly improves the thrust regulation accuracy.

[0019] Those skilled in the art will recognize additional features and advantages upon reading the detailed description and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 The flowchart of an embodiment of a thrust adjustment guidance method based on speed and overload according to an embodiment of the present invention.

[0022] Figure 2 It is a flow chart of another embodiment of the thrust adjustment guidance method based on speed and overload according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the purposes, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with 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 are used to illustrate 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 areas in the drawings may be enlarged for other structural components or areas to facilitate understanding of the embodiments of the present invention.

[0024] The directional words appearing in the following description refer to the directions shown in the drawings and do not 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 specified, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0025] In addition, the terms "include", "comprising", "having" or any other variations thereof are intended to cover non-exclusive inclusion, so that a structure or component comprising a series of elements includes not only those elements, but also other mechanical elements not explicitly listed or inherent in the structure or component. In the absence of more limitations, the elements defined by the sentence "comprising..." do not exclude the presence of other identical elements in the article or device comprising the elements.

[0026] Spatially relative terms such as "below," "beneath," "under," "low," "above," "on," "high," and the like are used to facilitate description to explain the positioning of one element relative to a second element, indicating that these terms are intended to encompass different orientations of the device in addition to orientations different from those shown in the figures. In addition, for example, "one element is above / below another element" can mean that the two elements are in direct contact or that there are other elements between the two elements. Furthermore, terms such as "first," "second," and the like are also used to describe various elements, regions, portions, and the like, and should not be considered limiting. Similar terms are used throughout the description to represent similar elements.

[0027] For those skilled in the art, the present invention can be implemented without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present invention by showing examples of the present invention.

[0028] The present invention provides a thrust adjustment guidance method based on speed and overload, which can accurately adjust the engine thrust during flight, thereby achieving high-precision trajectory tracking of the carrier rocket.

[0029] In one embodiment, the thrust adjustment guidance method based on speed and overload proposed by the present invention comprises the following specific steps: Step 1: Bind the standard speed value Vcx corresponding to the standard altitude of the launch vehicle, the average overload value Acx corresponding to the standard altitude, the speed adjustment coefficient Kv corresponding to the standard altitude, the overload adjustment coefficient Ka corresponding to the standard altitude, the starting thrust adjustment characteristic value Wstart, the ending thrust adjustment characteristic value Wend, and the thrust adjustment threshold dAstd; Step 2: Obtain the overload of the current and previous flight moments in real time, smooth the overload over a period of time to obtain overload A. The smoothing time is generally 5 to 100 control cycles. Step 3: Get the current flight speed in real time to get the speed V; Step 4. Calculate the thrust adjustment coefficient dVA based on the current state: dVA = Kv × (V-Vcx) + Ka × (A-Acx); Step 5: Compare the current thrust adjustment coefficient with the thrust adjustment threshold dVAstd to calculate the throttling ratio and then perform thrust adjustment.

[0030] This embodiment uses flight altitude as a characteristic variable for discrimination, but this can be further modified to include other physical quantities such as flight time and flight position, depending on actual circumstances. Furthermore, the speed and overload shown in this embodiment are combined speeds and combined overloads. The use of a split-channel design allows the thrust regulation method of this embodiment to be applied in different directions.

[0031] See also Figure 1 The present invention provides a thrust adjustment and guidance method based on speed and overload, which includes at least the following steps: S100, binding at least the standard speed value Vcx corresponding to the standard characteristic value of the launch vehicle, the average overload value Acx corresponding to the standard characteristic value, the speed adjustment coefficient Kv corresponding to the standard characteristic value, the overload adjustment coefficient Ka corresponding to the standard characteristic value, the starting thrust adjustment characteristic value Wstart, the ending thrust adjustment characteristic value Wend, and the thrust adjustment threshold dVAstd; S200, determining whether the current characteristic value reaches the thrust characteristic value Wstart for starting adjustment. If the characteristic value does not meet the adjustment requirement, the next determination cycle is entered for further determination until the current characteristic value reaches the thrust characteristic value Wstart for starting adjustment. S300, obtaining the current speed value V and overload value A; S400, using the standard feature interpolation to feedback the speed adjustment coefficient Kv corresponding to the standard feature, the overload adjustment coefficient Ka corresponding to the standard feature, the theoretical speed Vcx corresponding to the standard feature, and the theoretical apparent acceleration Acx; S500. Use the thrust adjustment formula: dVA = Kv × (V - Vcx) + Ka × (A - Acx) to calculate the thrust adjustment coefficient dVA; S600 , comparing the thrust adjustment coefficient dVA with the thrust adjustment threshold dVAstd to obtain a throttle ratio, and adjusting the engine thrust according to the throttle ratio.

[0032] The characteristic quantity in this embodiment can be selected from physical quantities such as flight altitude, flight time, and flight position. In the embodiment of the present invention, flight altitude is selected as the characteristic quantity for discrimination, and the specific steps are as follows: Sp100, binding at least the standard speed value Vcx corresponding to the standard altitude of the launch vehicle, the average overload value Acx corresponding to the standard altitude, the speed adjustment coefficient Kv corresponding to the standard altitude, the overload adjustment coefficient Ka corresponding to the standard altitude, the starting thrust adjustment characteristic value Wstart, the ending thrust adjustment characteristic value Wend, and the thrust adjustment threshold dVAstd; Sp200, determine whether the current flight altitude reaches the thrust characteristic value Wstart for starting adjustment. If the determination and adjustment are not satisfied, enter the next determination cycle for re-determination until the current flight altitude reaches the thrust characteristic value Wstart for starting adjustment. Sp300, obtain the current speed value V and overload value A; Sp400 uses the standard altitude (standard flight altitude) to interpolate and feedback the speed adjustment coefficient Kv corresponding to the standard altitude, the overload adjustment coefficient Ka corresponding to the standard altitude, the theoretical speed Vcx corresponding to the standard altitude, and the theoretical apparent acceleration Acx; Sp500, use the thrust adjustment formula: dVA = Kv × (V-Vcx) + Ka × (A-Acx) to calculate the thrust adjustment coefficient dVA; Sp600, compare the thrust adjustment coefficient dVA with the thrust adjustment threshold dVAstd to obtain the throttle ratio, and adjust the engine thrust according to the throttle ratio.

[0033] Furthermore, after the thrust adjustment coefficient dVA is obtained by calculation in Sp500, it also includes: judging whether the current flight altitude reaches the end adjustment thrust characteristic value Wend; if it does not meet the judgment adjustment, proceed to the next step; if it meets the judgment adjustment, end the thrust adjustment.

[0034] See also Figure 2 After the thrust adjustment process begins, it is determined whether the current characteristic value (flight altitude W) reaches the thrust adjustment characteristic value Wstart. The determination method is: determine whether |W-Wstart| < If the judgment result is yes, then proceed directly to the next thrust adjustment step; if the judgment result is no, then enter the next judgment cycle and judge again until the current characteristic value (flight altitude W) reaches the starting thrust adjustment characteristic value Wstart. The value range is 0.01±0.05.

[0035] Furthermore, if |W-Wstart|< , then start to obtain the current speed value V and overload value A. In this embodiment, the method for obtaining the current speed value V is to obtain the module value of the flight speed solved by the navigation in the current control cycle, specifically: calculated by the following formula: ,in They are the speed values ​​in the three directions of the navigation coordinate system.

[0036] The method for obtaining the overload value A is to obtain the average value of the overload modulus values ​​of the current control cycle and the previous control cycle. Specifically, the overload value A is calculated using the following formula: , ， Where N is the number of control cycles used for smoothing, are the apparent acceleration values ​​in three directions in the rocket body coordinate system.

[0037] In the above embodiment, the number N of control cycles used for smoothing ranges from 5 to 100.

[0038] Furthermore, Sp400 uses the standard flight altitude to interpolate and feedback the speed adjustment coefficient Kv corresponding to the standard altitude, the overload adjustment coefficient Ka corresponding to the standard altitude, the theoretical speed Vcx corresponding to the standard altitude, and the theoretical apparent acceleration Acx corresponding to the standard altitude as follows: Step 1: Interpolate and feedback the theoretical speed Vcx and theoretical apparent acceleration Acx corresponding to the standard altitude according to the current flight altitude. The theoretical speed Vcx and theoretical apparent acceleration Acx corresponding to the standard altitude Hcx are shown in Table 1, and the standard altitude Hcx is the independent variable. Table 1 Step 2: Interpolate and feedback the overload adjustment coefficient Ka and speed adjustment coefficient Kv according to the current flight altitude. The speed adjustment coefficient Kv corresponding to the standard altitude Hcx and the overload adjustment coefficient Ka corresponding to the standard altitude are shown in Table 2. The standard altitude is the independent variable.

[0039] Table 2 It should be noted that in the above embodiment, flight altitude is used as the discriminant W for thrust adjustment. However, other physical quantities such as flight time and position can also be used as the discriminant W. For example, if flight time is used as the discriminant W, Wstart is the time when thrust adjustment begins, and Wend is the time when thrust adjustment ends. The interpolated independent variable becomes the standard flight time. Specifically, the interpolation feedback process is as follows: according to the current flight time, the theoretical speed and theoretical apparent acceleration corresponding to the standard flight time are interpolated and fed back; according to the current flight time, the overload adjustment coefficient and speed adjustment coefficient are interpolated and fed back.

[0040] In any of the above embodiments, the thrust adjustment formula: dVA = Kv × (V-Vcx) + Ka × (A-Acx) is used to calculate the thrust adjustment coefficient dVA, and then a characteristic value judgment is performed. It is determined whether the current flight altitude W reaches the end-adjustment thrust characteristic value Wend. If the judgment adjustment is not satisfied, the next step is continued. If the judgment adjustment is satisfied, the entire thrust adjustment process is terminated. Specifically: determine whether |W-Wend| < If the judgment result is yes, then the current adjustment process ends directly; if the judgment result is no, then the next adjustment step Sp600 is directly performed. The value range is 0.01±0.05.

[0041] Furthermore, Sp600 compares the thrust adjustment coefficient dVA with the thrust adjustment threshold dVAstd to obtain the throttle ratio. The method for adjusting the engine thrust according to the throttle ratio is: Compare the thrust adjustment coefficient with the thrust adjustment threshold dVAstd and calculate the throttling ratio that needs to be adjusted using the following formula: : , Wherein, dVAstd is the thrust adjustment threshold, dtj is the thrust adjustment step size, and dVA is the thrust adjustment coefficient; Then calculate the current throttling ratio using the following formula: : ,in is the throttling ratio of the previous cycle; According to the current throttling ratio Determine engine thrust and make rapid adjustments to engine thrust in real time.

[0042] The thrust adjustment threshold dVAstd is given based on engine test data and speed overload data, and the thrust adjustment step length dtj is given based on engine test data.

[0043] The above embodiments can be combined with each other and have corresponding technical effects.

[0044] 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 in the scope of protection of the present invention.

Claims

1. A thrust adjustment guidance method based on speed and overload, characterized in that: At least the following steps are included: Binding at least the standard speed value Vcx corresponding to the standard characteristic quantity of the launch vehicle, the average overload value Acx corresponding to the standard characteristic quantity, the speed adjustment coefficient Kv corresponding to the standard characteristic quantity, the overload adjustment coefficient Ka corresponding to the standard characteristic quantity, the starting thrust adjustment characteristic quantity Wstart, the ending thrust adjustment characteristic quantity Wend, and the thrust adjustment threshold dVAstd; Determine whether the current characteristic value reaches the starting thrust adjustment characteristic value Wstart. If it does not meet the determination adjustment, enter the next determination cycle for re-determination until the current characteristic value reaches the starting thrust adjustment characteristic value Wstart. Get the current speed value V and overload value A; The speed adjustment coefficient Kv corresponding to the standard characteristic quantity, the overload adjustment coefficient Ka corresponding to the standard characteristic quantity, the theoretical speed Vcx corresponding to the standard characteristic quantity, and the theoretical apparent acceleration Acx corresponding to the standard characteristic quantity are fed back by interpolation of the standard characteristic quantity; Use the thrust adjustment formula: dVA = Kv × (V-Vcx) + Ka × (A-Acx) to calculate the thrust adjustment coefficient dVA; The thrust adjustment coefficient dVA is compared with the thrust adjustment threshold dVAstd to obtain the throttle ratio, and the engine thrust is adjusted according to the throttle ratio.

2. The thrust adjustment guidance method based on speed and overload according to claim 1, characterized in that: After the thrust adjustment coefficient dVA is obtained by calculation, the method further includes: Determine whether the current characteristic value reaches the end adjustment thrust characteristic value Wend. If it does not meet the determination adjustment, proceed to the next step. If it meets the determination adjustment, end the thrust adjustment.

3. The thrust adjustment guidance method based on speed and overload according to claim 2, characterized in that: The method for obtaining the current speed value V is to obtain the module value of the flight speed solved by navigation in the current control cycle, which is specifically calculated by the following formula: ,in They are the speed values ​​in the three directions of the navigation coordinate system.

4. The thrust adjustment guidance method based on speed and overload according to claim 3, characterized in that: The method for obtaining the overload value A is to obtain an average value of the overload modulus values ​​of the current control cycle and the previous control cycle.

5. The thrust adjustment guidance method based on speed and overload according to claim 4, characterized in that: The method for obtaining the average value of the overload modulus values ​​of the current control cycle and the previous control cycle is: Calculated by the following formula: , ， Where N is the number of control cycles, are the apparent acceleration values ​​in three directions in the rocket body coordinate system.

6. The thrust adjustment guidance method based on speed and overload according to any one of claims 1 to 5, characterized in that: The thrust adjustment coefficient dVA is compared with the thrust adjustment threshold dVAstd to obtain the throttle ratio. The method for adjusting the engine thrust according to the throttle ratio is as follows: Compare the thrust adjustment coefficient with the thrust adjustment threshold dVAstd and calculate the throttling ratio that needs to be adjusted using the following formula: : ， Wherein, dVAstd is the thrust adjustment threshold, dtj is the thrust adjustment step size, and dVA is the thrust adjustment coefficient; The current throttling ratio is calculated by the following formula : ,in is the throttling ratio of the previous cycle; According to the current throttling ratio Determine engine thrust and make rapid adjustments to engine thrust in real time.

7. The thrust adjustment guidance method based on speed and overload according to claim 6, characterized in that: The thrust adjustment threshold dVAstd is comprehensively given based on the engine test data and the speed overload data; and the thrust adjustment step length dtj is given based on the engine test data.

8. The thrust adjustment guidance method based on speed and overload according to claim 1, characterized in that: The method for determining whether the current characteristic value reaches the thrust characteristic value Wstart for starting to adjust is: Determine whether |W-Wstart| is < If the judgment result is yes, then proceed directly to the next adjustment step; if the judgment result is no, then enter the next judgment cycle for re-judgment.

9. The thrust adjustment guidance method based on speed and overload according to claim 8, characterized in that: described The value range is 0.01±0.

05.

10. The thrust adjustment guidance method based on speed and overload according to claim 5, characterized in that: The control cycle number N ranges from 5 to 100.

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