A speed and overload based thrust regulation guidance method

Abstract

The application provides a speed and overload based thrust adjusting guidance method, and the steps are as follows: standard speed value Vcx corresponding to standard altitude of a carrier rocket, average overload value Acx corresponding to the standard altitude, speed adjusting coefficient Kv corresponding to the standard altitude, overload adjusting coefficient Ka corresponding to the standard altitude, starting adjusting thrust characteristic quantity Wstart, ending adjusting thrust characteristic quantity Wend and thrust adjusting threshold dAstd are bound; real-time acquisition of overloads at current and previous flight time and smooth processing to obtain the overloads A; real-time acquisition of speed at the current flight time to obtain the speed V; calculation of the thrust adjusting coefficient dVA according to the current state: dVA=Kv×(V‑Vcx)+Ka×(A‑Acx); comparison of the thrust adjusting coefficient of the current state with the thrust adjusting threshold dVAstd, calculation of the throttle ratio, and then thrust adjusting.

Description

Technical Field

[0001] This invention relates to the field of aerospace launch vehicle technology, and in particular to a thrust adjustment guidance method based on velocity and overload. Background Technology

[0002] Reusable liquid rockets will be a key research direction for reducing rocket costs and increasing efficiency in the future, while engines with a wide range of adjustable thrust are a key technology for achieving low-cost, reusable rockets. In addition to meeting the accuracy requirements of the payload, reusable rockets also need to consider the precise landing of the stages. How to adjust thrust during recovery to ensure accurate trajectory tracking and how to guarantee high-precision rocket recovery are urgent problems to be solved.

[0003] In the invention patent CN114109652B "A method and device for adjusting the 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 adjustment. Furthermore, directly using the overload integral term can easily introduce interference noise during the flight process, and the interference information is amplified after integration.

[0004] In the invention patent CN112304169B, "A guidance method and system for launch vehicles based on thrust adjustment", calculating the target thrust requires estimating the mass of the rocket body. However, the mass of the rocket body during flight is difficult to estimate accurately, and using only speed to adjust the thrust will cause the adjustment results to lag and fail to respond in a timely manner.

[0005] Therefore, there is an urgent need to provide a thrust regulation guidance method that is responsive and has minimal interference. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a thrust adjustment guidance method based on velocity and overload, which can precisely adjust engine thrust during flight, thereby achieving high-precision trajectory tracking of the launch vehicle.

[0007] This invention provides a thrust regulation guidance method based on velocity and overload, comprising at least the following steps:

[0008] Step 1: At least the following parameters are set: standard velocity value Vcx, average overload value Acx, velocity adjustment coefficient Kv, overload adjustment coefficient Ka, thrust characteristic value Wstart, thrust characteristic value Wend, and thrust adjustment threshold dVAstd corresponding to the standard characteristic quantities of the launch vehicle.

[0009] Step 2: Determine whether the current characteristic quantity has reached the thrust characteristic quantity Wstart to start adjusting. If the determination is not met, proceed to the next determination cycle for re-determination until the current characteristic quantity reaches the thrust characteristic quantity Wstart to start adjusting.

[0010] Step 3: Obtain the current speed value V and overload value A;

[0011] Step 4: Use standard characteristic quantities to interpolate and feed back the speed adjustment coefficient Kv, the overload adjustment coefficient Ka, the theoretical speed Vcx, and the theoretical apparent acceleration Acx corresponding to the standard characteristic quantities;

[0012] Step 5: Use the thrust adjustment formula: dVA=Kv×(V-Vcx)+Ka×(A-Acx) to calculate the thrust adjustment coefficient dVA;

[0013] 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.

[0014] Furthermore, after calculating the thrust adjustment coefficient dVA using the thrust adjustment formula dVA=Kv×(V-Vcx)+Ka×(A-Acx) in step five, the method further includes: determining whether the current characteristic quantity has reached the thrust characteristic quantity Wend to end the adjustment. If the determination adjustment is not met, the next step is continued; if the determination adjustment is met, the thrust adjustment ends.

[0015] Furthermore, the method for obtaining the current speed value V is as follows: obtain the modulus of the flight speed calculated by navigation within the current control cycle, specifically calculated using the following formula: ,in These are the velocity values ​​in the three directions of the navigation coordinate system.

[0016] Furthermore, the method for obtaining the overload value A is as follows: obtain the average value of the overload magnitude of the current control cycle and the previous control cycle.

[0017] Furthermore, the method for obtaining the average value of the overload magnitude of the current control cycle and the previous control cycle is as follows:

[0018] It is calculated using the following formula: , ，

[0019] Where N is the number of control cycles. These are the apparent acceleration values ​​in three directions in the arrow's coordinate system.

[0020] Furthermore, in any of the above embodiments, the method for comparing the thrust adjustment coefficient dVA with the thrust adjustment threshold dVAstd in step six to obtain the throttle ratio, and adjusting the engine thrust according to the throttle ratio, is as follows:

[0021] The thrust adjustment coefficient is compared with the thrust adjustment threshold dVAstd, and the required throttle ratio is calculated using the following formula. :

[0022] ,

[0023] Where dVAstd is the thrust adjustment threshold, dtj is the thrust adjustment step size, and dVA is the thrust adjustment coefficient;

[0024] The current throttling ratio is calculated using the following formula. : ,in The throttling ratio of the previous cycle;

[0025] Based on the current throttling ratio Determine the engine thrust and make real-time, rapid adjustments to the engine thrust.

[0026] Furthermore, the thrust adjustment threshold dVAstd is given based on a combination of engine test data and speed overload data; the thrust adjustment step size dtj is given based on engine test data.

[0027] Furthermore, the method for determining whether the current characteristic quantity has reached the threshold for adjusting the thrust characteristic quantity Wstart is as follows: determine whether |W - Wstart| < If the judgment result is yes, then proceed directly to the next adjustment step; if the judgment result is no, then proceed to the next judgment cycle for re-judgment.

[0028] Furthermore, the aforementioned The value range is 0.01±0.05.

[0029] Furthermore, the number of control cycles N ranges from 5 to 100.

[0030] This invention provides a thrust adjustment guidance method based on velocity and overload, which can rapidly adjust the thrust in real time according to the actual flight situation, thereby achieving precise trajectory tracking. When applied to reusable rockets, this thrust adjustment guidance method enables reusable launch vehicles to accurately return to the landing site. Previously, this thrust adjustment guidance method has been successfully applied to the ZQ-3 launch vehicle's vertical takeoff and vertical recovery test rocket.

[0031] The flight overload used in the thrust regulation guidance method based on speed and overload of the present invention is filtered and smoothed to effectively prevent interference signals from entering the thrust regulation loop. Overload and speed regulation constitute PD control, which greatly improves the thrust regulation accuracy.

[0032] Upon reading the detailed embodiments and examining the accompanying drawings, those skilled in the art will recognize additional features and advantages. Attached Figure Description

[0033] 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.

[0034] Figure 1 This is a flowchart of one embodiment of the thrust adjustment guidance method based on velocity and overload according to the present invention.

[0035] Figure 2 This is a flowchart illustrating another embodiment of the thrust adjustment guidance method based on speed and overload according to the present invention. Detailed Implementation

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] This invention provides a thrust adjustment guidance method based on velocity and overload, which can precisely adjust engine thrust during flight, thereby achieving high-precision trajectory tracking of launch vehicles.

[0042] In one embodiment, the thrust adjustment guidance method based on velocity and overload proposed in this invention comprises the following steps:

[0043] Step 1: Set up the following parameters: standard velocity value Vcx corresponding to the standard altitude of the launch vehicle, average overload value Acx corresponding to the standard altitude, velocity adjustment coefficient Kv corresponding to the standard altitude, overload adjustment coefficient Ka corresponding to the standard altitude, thrust characteristic quantity Wstart for starting adjustment, thrust characteristic quantity Wend for ending adjustment, and thrust adjustment threshold dAstd.

[0044] Step 2: Obtain the overload of the current and previous flight times 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.

[0045] Step 3: Obtain the speed at the current flight moment in real time to get the speed V;

[0046] Step 4: Calculate the thrust adjustment coefficient dVA based on the current state: dVA = Kv × (V - Vcx) + Ka × (A - Acx);

[0047] Step 5: Compare the thrust adjustment coefficient of the current state with the thrust adjustment threshold dVAstd to calculate the throttle ratio, and then adjust the thrust.

[0048] This embodiment uses flight altitude as a characteristic quantity for discrimination, but it can also be further modified to include other physical quantities such as flight time and flight position, depending on the actual situation. Furthermore, the speed and overload given in this embodiment are resultant speeds and resultant overloads, and a split-channel design is adopted, allowing the thrust adjustment method of this embodiment to be used in different directions.

[0049] See Figure 1 The present invention provides a thrust adjustment guidance method based on velocity and overload, comprising at least the following steps:

[0050] S100, at least the standard velocity value Vcx corresponding to the standard characteristic quantity of the launch vehicle, the average overload value Acx corresponding to the standard characteristic quantity, the velocity adjustment coefficient Kv corresponding to the standard characteristic quantity, the overload adjustment coefficient Ka corresponding to the standard characteristic quantity, the thrust characteristic quantity to start adjustment Wstart, the thrust characteristic quantity to end adjustment Wend, and the thrust adjustment threshold dVAstd are loaded.

[0051] S200: Determine whether the current characteristic quantity has reached the thrust characteristic quantity Wstart to start adjusting. If the determination adjustment is not met, proceed to the next determination cycle for re-determination until the current characteristic quantity reaches the thrust characteristic quantity Wstart to start adjusting.

[0052] S300: Obtain the current speed value V and overload value A;

[0053] S400, using standard characteristic quantity interpolation feedback of 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 and the theoretical apparent acceleration Acx corresponding to the standard characteristic quantity;

[0054] S500, using the thrust adjustment formula: dVA=Kv×(V-Vcx)+Ka×(A-Acx), the thrust adjustment coefficient dVA is calculated;

[0055] S600: 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.

[0056] In this embodiment, the feature quantity can be selected from physical quantities such as flight altitude, flight time, and flight position. In this embodiment of the invention, flight altitude is selected as the feature quantity for discrimination, and the specific steps are as follows:

[0057] Sp100, at least the standard velocity value Vcx corresponding to the standard altitude of the launch vehicle, the average overload value Acx corresponding to the standard altitude, the velocity adjustment coefficient Kv corresponding to the standard altitude, the overload adjustment coefficient Ka corresponding to the standard altitude, the thrust characteristic quantity Wstart to start adjustment, the thrust characteristic quantity Wend to end adjustment, and the thrust adjustment threshold dVAstd are loaded.

[0058] Sp200: Determine whether the current flight altitude has reached the thrust characteristic value Wstart to start adjusting. If the determination is not met, proceed to the next determination cycle for re-determination until the current flight altitude reaches the thrust characteristic value Wstart to start adjusting.

[0059] Sp300: Obtain the current speed value V and overload value A;

[0060] Sp400 uses standard altitude (standard flight altitude) interpolation feedback to provide the speed adjustment coefficient Kv, the overload adjustment coefficient Ka, the theoretical speed Vcx, and the theoretical apparent acceleration Acx corresponding to the standard altitude;

[0061] For Sp500, the thrust adjustment formula is used: dVA=Kv×(V-Vcx)+Ka×(A-Acx) to calculate the thrust adjustment coefficient dVA;

[0062] Sp600 compares the thrust adjustment coefficient dVA with the thrust adjustment threshold dVAstd to obtain the throttle ratio, and adjusts the engine thrust according to the throttle ratio.

[0063] Furthermore, after calculating the thrust adjustment coefficient dVA in Sp500, it also includes: determining whether the current flight altitude has reached the end of the thrust adjustment characteristic quantity Wend. If the determination adjustment is not met, the next step is continued; if the determination adjustment is met, the thrust adjustment ends.

[0064] See Figure 2 After the thrust adjustment process begins, it is determined whether the current characteristic quantity (flight altitude W) has reached the thrust characteristic quantity Wstart at the start of the adjustment. The determination method is: determine whether |W - Wstart| < If the judgment result is yes, the next thrust adjustment step is directly performed; if the judgment result is no, the next judgment cycle is entered for re-judgment, until the current characteristic quantity (flight altitude W) reaches the thrust adjustment characteristic quantity Wstart. The value range is 0.01±0.05.

[0065] Furthermore, if |W-Wstart| < Then, the current speed value V and overload value A are acquired. In this embodiment, the current speed value V is acquired by obtaining the modulus of the flight speed calculated by navigation within the current control cycle, specifically calculated using the following formula: ,in These are the velocity values ​​in the three directions of the navigation coordinate system.

[0066] The overload value A is obtained by averaging the overload magnitudes of the current control cycle and the previous control cycle, specifically by calculating the overload value A using the following formula:

[0067] , ，

[0068] Where N is the number of control cycles used for smoothing. These are the apparent acceleration values ​​in three directions in the arrow's coordinate system.

[0069] In the above embodiments, the number of control cycles N used for smoothing ranges from 5 to 100.

[0070] Furthermore, the method for Sp400 to interpolate and feedback the speed adjustment coefficient Kv, the overload adjustment coefficient Ka, the theoretical speed Vcx, and the theoretical apparent acceleration Acx corresponding to the standard flight altitude is as follows:

[0071] Step 1: Interpolate the theoretical velocity Vcx and theoretical apparent acceleration Acx corresponding to the standard altitude according to the current flight altitude. The theoretical velocity Vcx and theoretical apparent acceleration Acx corresponding to the standard altitude Hcx are shown in Table 1. The standard altitude Hcx is the independent variable.

[0072]

[0073] Table 1

[0074] Step 2: Interpolate the feedback 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.

[0075]

[0076] Table 2

[0077] It should be noted that in the above embodiment, flight altitude is used as the discriminant quantity W for adjustment. However, other physical quantities such as flight time and position can also be used as the discriminant quantity W. For example, if flight time is used as the discriminant quantity W, Wstart is the start time of adjustment, Wend is the end time of adjustment, and the interpolation independent variable becomes the standard flight time. Specifically, the interpolation feedback process is as follows: interpolate the theoretical velocity and theoretical apparent acceleration corresponding to the standard flight time according to the current flight time; interpolate the overload adjustment coefficient and velocity adjustment coefficient according to the current flight time.

[0078] In any of the above embodiments, the thrust adjustment coefficient dVA is calculated using the thrust adjustment formula: dVA = Kv × (V - Vcx) + Ka × (A - Acx), and then a characteristic quantity discrimination is performed. It is determined whether the current flight altitude W has reached the thrust characteristic quantity Wend that ends the adjustment. If the discrimination adjustment is not satisfied, the next step is performed; if the discrimination adjustment is satisfied, the entire thrust adjustment process ends. Specifically, it is determined whether |W - Wend| < If the determination result is yes, the current adjustment and push process ends directly; if the determination result is no, the next adjustment and push step Sp600 is performed directly. The value range is 0.01±0.05.

[0079] Furthermore, the 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 based on the throttle ratio is as follows:

[0080] The thrust adjustment coefficient is compared with the thrust adjustment threshold dVAstd, and the required throttle ratio is calculated using the following formula. :

[0081] ,

[0082] Where dVAstd is the thrust adjustment threshold, dtj is the thrust adjustment step size, and dVA is the thrust adjustment coefficient;

[0083] Then calculate the current throttling ratio using the following formula. : ,in The throttling ratio of the previous cycle;

[0084] Based on the current throttling ratio Determine the engine thrust and make real-time, rapid adjustments to the engine thrust.

[0085] The thrust adjustment threshold dVAstd is given based on a combination of engine test data and speed overload data. The thrust adjustment step size dtj is given based on engine test data.

[0086] The above embodiments can be combined with each other and have corresponding technical effects.

[0087] 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 thrust adjustment guidance method based on velocity and overload, characterized in that, At least the following steps are included: At least the standard velocity value Vcx, the average overload value Acx, the velocity adjustment coefficient Kv, the overload adjustment coefficient Ka, the thrust characteristic value Wstart, the thrust characteristic value Wend, and the thrust adjustment threshold dVAstd corresponding to the standard characteristic values ​​of the launch vehicle should be assembled. Determine whether the current characteristic value has reached the thrust characteristic value Wstart to start adjusting. If the determination is not met, proceed to the next determination cycle for re-determination until the current characteristic value reaches the thrust characteristic value Wstart to start adjusting. Obtain the current speed value V and overload value A; The standard characteristic quantity is used to interpolate and feed back the speed adjustment coefficient Kv, the overload adjustment coefficient Ka, the theoretical speed Vcx, and the theoretical apparent acceleration Acx corresponding to the standard characteristic quantity; The thrust adjustment coefficient dVA can be calculated using the thrust adjustment formula: dVA=Kv×(V-Vcx)+Ka×(A-Acx); The throttle ratio is obtained by comparing the thrust adjustment coefficient dVA with the thrust adjustment threshold dVAstd, and the engine thrust is adjusted according to the throttle ratio.

2. The thrust adjustment guidance method based on velocity and overload according to claim 1, characterized in that, After obtaining the thrust adjustment coefficient dVA through calculation, the method further includes: Determine whether the current characteristic value has reached the final thrust characteristic value Wend. If the determination is not met, continue to the next step. If the determination is met, end the thrust adjustment.

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

4. The thrust adjustment guidance method based on velocity and overload according to claim 3, characterized in that, The method for obtaining the overload value A is as follows: obtain the average value of the overload magnitude of the current control cycle and the previous control cycle.

5. The thrust adjustment guidance method based on velocity and overload according to claim 4, characterized in that, The method for obtaining the average value of the overload modulus of the current control cycle and the previous control cycle is as follows: It is calculated using the following formula: , ， Where N is the number of control cycles. These are the apparent acceleration values ​​in three directions in the arrow's coordinate system.

6. The thrust regulation guidance method based on velocity and overload according to any one of claims 1 to 5, characterized in that, The method of comparing the thrust adjustment coefficient dVA with the thrust adjustment threshold dVAstd to obtain the throttle ratio, and adjusting the engine thrust according to the throttle ratio, is as follows: The thrust adjustment coefficient is compared with the thrust adjustment threshold dVAstd, and the required throttle ratio is calculated using the following formula. : ， Where 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 using the following formula. : ,in The throttling ratio of the previous cycle; Based on the current throttling ratio Determine the engine thrust and make real-time, rapid adjustments to the engine thrust.

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

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

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

05.

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

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