Interstage non-explosive separation design method suitable for reusable rockets

Abstract

The application relates to a stage non-explosive separation design method suitable for a reusable rocket, and the method comprises the following steps: forming a separation scheme evaluation criterion according to top-level requirements of a task; determining input conditions and design constraints of stage non-explosive separation of the reusable rocket as design basis; determining a separation mode, a connection unlocking mode, a separation guiding requirement and a separation energy form according to the evaluation criterion and the design basis; establishing a preliminary separation simulation model to determine overall separation design indexes; determining separation device technical indexes; under the design parameters of the separation device technical indexes, the design indexes are checked and the separation simulation model is corrected through multi-body dynamics simulation and separation principle prototype test; and the closed-loop design of the separation device technical indexes and the overall separation design indexes is iteratively completed. The application solves the problem that the separation process does not occur structural interference under the problems of coordination of separation speed, separation deviation, structure bearing capacity, separation elasticity and deviation interference.

Description

Technical Field

[0001] This invention belongs to the field of aerospace systems technology and relates to a non-pyrotechnic separation design method for reusable rockets. Background Technology

[0002] Non-pyrotechnic separation technology relies on the next-generation near-Earth manned rocket. The primary mission of this new generation of near-Earth manned rockets is to send spacecraft (manned and cargo spacecraft) into near-Earth space station orbit and to achieve the controlled recovery and reuse of the first stage. The aim is to achieve rapid and efficient space travel and transportation. Unlike expendable rockets, the essential characteristic is that the first stage can be recovered, and after economically feasible testing and maintenance, it can be quickly relaunched. First and second stage separation involves the separation of the reusable first stage, requiring a separation device to unlock the interstage connection and provide separation energy, while ensuring that the reuse of the first stage is not affected. Common separation devices include pyrotechnic and non-pyrotechnic separation devices. Non-pyrotechnic separation devices are suitable for reusable rockets due to their detectability, reusability, and lack of pollution. Internationally, reusable launch vehicles, such as SpaceX's Falcon 9 / Falcon H, have successfully implemented non-pyrotechnic separation devices, completely replacing pyrotechnic components.

[0003] Interstage non-pyrotechnic separation is a new technology, and the use of a high-thrust gas-driven propulsion and guidance mechanism as the separation energy source is a first for domestic launch vehicles. It requires balancing the overall requirements of various disciplines and the overall separation performance, comprehensively coordinating separation speed, separation deviation, and structural load-bearing capacity. It also necessitates addressing complex elasticity issues during separation to ensure that structural interference does not occur under various possible deviations and disturbances, and that the impact of these deviations on subsequent flight is controllable, without affecting the safety of continued flight after the first and second stages separate. Based on these technical challenges, there is an urgent need to research interstage non-pyrotechnic separation design methods suitable for reusable rockets. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a non-pyrotechnic separation design method for reusable rockets. This method addresses the technical problem of balancing the overall requirements of various disciplines and the overall separation performance in non-pyrotechnic separation technology, comprehensively coordinating separation speed, separation deviation, and structural load-bearing capacity, and also considering the complex elasticity issues during separation. It ensures that no structural interference occurs during the process under various possible deviation interferences, and makes the impact of deviation interferences generated during interstage separation on subsequent flight controllable, without affecting the safety of continued flight after the separation of the first and second stage rocket bodies.

[0005] The solution provided by this invention is a non-pyrotechnic separation design method for reusable rockets, comprising the following steps:

[0006] Step 1: Based on the top-level requirements for interstage separation in reusable rocket engineering missions, formulate separation scheme evaluation criteria;

[0007] Step 2: Determine the input conditions and design constraints for the interstage non-pyrotechnic separation of reusable rockets as the basis for design;

[0008] Step 3: Based on the evaluation criteria and design basis of the separation scheme, determine the separation method, connection unlocking method, separation guidance requirements, and separation energy form;

[0009] Step 4: Based on the determined separation method, connection unlocking method, separation guidance requirements, and separation energy form, establish a preliminary separation simulation model. According to the separation scheme evaluation criteria and design basis, determine the overall separation design indicators, including separation time T, separation distance D, relative separation velocity V, separation attitude deviation ΔA, and separation attitude angular velocity.

[0010] Step 5: Determine the technical specifications of the separation device, including the amount of energy to be separated (n), impulse (I), and peak thrust (F). max Thrust deviation ΔF, structural deformation ε1, structural installation deviation ε2;

[0011] Step 6: Under the design parameters of the separation device's technical specifications, verify the overall separation design parameters and correct the separation simulation model through multibody dynamics simulation and separation principle prototype testing;

[0012] Step 7: Repeat steps 4 to 6 to iterate and complete the closed-loop design of the technical indicators of the separation device and the overall design indicators of the separation. Based on the set overall performance requirements, select the optimal closed-loop design scheme.

[0013] Furthermore, the evaluation criteria for the separation scheme described in step 1 specifically include:

[0014] R1: The first and second stages of the rocket body can be reliably separated, allowing the second stage to continue the ascent phase and the first stage to continue the return phase.

[0015] R2: The separation scheme meets the economic requirements;

[0016] R3: After the first-stage rocket body is recovered, and after economically feasible testing and repair measures, it can be quickly organized for another launch;

[0017] R4: Separation devices used for interstage separation are characterized by being detectable and measurable.

[0018] Furthermore, the input conditions described in step 2 include:

[0019] The set masses m1 and m2 of the first and second stage arrow bodies, the set centers of mass c1 and c2 of the first and second stage arrow bodies, the set moments of inertia I1 and I2 of the first and second stage arrow bodies, the mass deviation range Δm1 and Δm2 of the first and second stage arrow bodies, the center of mass deviation range Δc1 and Δc2 of the first and second stage arrow bodies, and the moment of inertia deviation range ΔI1 and ΔI2 of the first and second stage arrow bodies;

[0020] Initial pitch, yaw, and roll attitude angular velocities of the first and second stage components before separation:

[0021] The thrust-time curve T1(t) after the first-stage engine shuts down;

[0022] The thrust-time curve T2(t) of the second-stage engine startup;

[0023] The curve P of the first-stage aerodynamic pressure variation of the second-stage engine with the distance between the first and second-stage rocket bodies 12 (d);

[0024] The curve Q of the first-stage aerodynamic heat flux of the second-stage engine as a function of the distance between the first and second stages of the rocket body. 12 (d);

[0025] Curve of carrying capacity loss as a function of separation time m c (T).

[0026] Furthermore, the design constraints described in step 2 include:

[0027] The loss of carrying capacity due to separation time m c (T)≤100kg;

[0028] The attitude angular velocity after the first stage of the rocket separates is no greater than in, These are the specified values ​​for the pitch, yaw, and roll angular velocities after the first-stage rocket body separates;

[0029] The attitude angular velocity after the second stage of the rocket separates is no greater than in, These are the specified values ​​for the pitch, yaw, and roll angular velocities after the second-stage rocket body separates;

[0030] According to the spatial layout constraints, the available spatial envelope Evp of the separation device is located within the annulus between the minimum available spatial radius R1 and the maximum available spatial radius R2: R1≤Evp≤R2;

[0031] The initial separation gap between the first-stage and second-stage rocket bodies is cl0, and the separation gap during the separation process must not be less than the preset safety gap cl1.

[0032] Furthermore, the method for determining the separation method in step 3 is as follows:

[0033] The analysis relates the evaluation criteria and design basis to the separation method, and assigns weights to the relevant criteria and design basis according to their importance to the engineering task and separation process. A weighted evaluation function based on these criteria and design basis is then established, including:

[0034] Establish a weighted evaluation function f1(R1, R3, P) 12 (d), Q 12 (d)) and then evaluate and select one of the two separation methods, cold separation and hot separation;

[0035] Then, a weighted evaluation function f2(R1, R2, R3, cl0, cl1) is established, and one of the two separation methods, primary separation and secondary separation, is selected for evaluation.

[0036] The method for determining the connection unlocking method is as follows:

[0037] Establish a weighted evaluation function f3(R1, R2, R3, R4, Evp, cl0), and then evaluate and select one of the two connection unlocking methods: point-type connection unlocking and line-type connection unlocking.

[0038] The method for determining the separation-oriented requirements is as follows:

[0039] A weighted evaluation function f4(R1, R2, R3, R4, Evp, cl0, cl1) is established to determine whether guidance is needed during the separation process.

[0040] The method for determining the form of separated energy is as follows:

[0041] Establish a weighted evaluation function f5(R1, R2, R3, R4, m1, m2, Evp, cl0) to determine the energy source form of separation as one or more of the following: gas drive, hydraulic drive, electric drive, nuclear power, or phase change energy drive.

[0042] Furthermore, the separation method is selected as cold separation or single separation; the connection unlocking method is selected as linear connection unlocking; the separation guidance requirement is selected as required guidance; and the separation energy form is selected as gas drive.

[0043] Furthermore, the separation time T mentioned in step 4 includes: the time interval t1 between the first-stage engine shutdown and the operation of the interstage connection unlocking device, and the second-stage engine start-up delay time t2, where T = t1 + t2; through preliminary separation simulation, the acceptable threshold T for the aftereffect thrust of the first-stage engine during interstage separation is determined. 1max Furthermore, based on the thrust-time curve after the first-stage engine shuts down, T1(t)≤T 1max Determine the lower limit of t1; apply the design constraint m of carrying capacity.c (t1+t2)≤100kg determines the upper limit of the values ​​of t1 and t2, thus obtaining the separation time T. max This determines the range of values ​​for t2;

[0044] The separation distance D: the threshold P for accepting aerodynamic pressure from the first-stage rocket body on the second-stage engine due to interstage separation. 12max The acceptable threshold Q for the influence of heat flow 12max Solve for P 12 (d)≤P 12max Q 12 (d)≤Q 12max Determine the lower limit D of the separation distance D. min ;

[0045] The relative separation velocity V is determined based on the range of t2 and the lower limit of the separation distance D, where V = D. min The range of values ​​for / t2;

[0046] The separation attitude deviation ΔA and the separation attitude angular velocity Based on the allowable separation gap and separation distance, determine the separation attitude deviation ΔA = (cl0 - cl1) / D min and separation attitude angular velocity

[0047] Furthermore, based on the optimization principles of reliability, economy, and minimum energy consumption, the lower limit V of the relative separation velocity is determined. min The separation time is taken as the upper limit T. max The lower limit of the separation distance is D. min ;

[0048] Based on the preliminary separation simulation model, the design constraints under the set overall separation design parameters are checked: the attitude angular velocity of the first-stage rocket body after separation should not exceed [value missing]. and the attitude angular velocity after the second stage of the rocket separates is not greater than The conditions for meeting the requirements are determined, and the constraints of the overall design indicators on the technical indicators of the separation device are identified.

[0049] Furthermore, the energy quantity n to be separated in step 5 is determined based on the total energy W required for primary and secondary separation and the energy W0 that a single separation unit can provide: n = W / W0. When initially calculating n, frictional losses and various deviations are neglected. Wherein, the total energy required for primary and secondary separation... v1 and v2 are the separation velocities of the first and second stage arrows, respectively. min =v2-v1, m1v1+m2v2=0 is determined;

[0050] The impulse I is calculated as follows: the impulse of a single separation device is I = m2v2 / n;

[0051] The peak thrust F max It is determined based on the structural bearing capacity and safety factor;

[0052] The determination of the thrust deviation ΔF, structural deformation ε1, and structural installation deviation ε2 takes into account the lateral load F caused by various deviations during the separation process. h The torque balance equations are established with the first-stage and second-stage rocket bodies as the objects of force respectively:

[0053]

[0054]

[0055] Among them, h1, L F1 L T1 h2, L F2 These represent the lever arms of the lateral load on the first-stage rocket body, the lever arm of the air-driven thrust on the first-stage rocket body, the lever arm of the after-effect thrust of the first-stage engine on the first-stage rocket body, the lever arm of the lateral load on the second-stage rocket body, and the lever arm of the air-driven thrust on the second-stage rocket body, respectively; F represents the thrust of the separation device; These represent the separation attitude angular velocities of the first-stage and second-stage rocket bodies, respectively. for The vector synthesis result;

[0056] Based on the aforementioned moment balance equation, a preliminary calculation is performed to determine the lateral load F. h The values ​​of thrust deviation ΔF are used to calculate the separation attitude deviation ΔA and separation attitude angular velocity using a separation simulation model. The structural deformation ε1 and structural installation deviation ε2 are determined based on the satisfaction of design constraints.

[0057] Furthermore, step 6 specifically includes:

[0058] Sub-step 61: Conduct rigid body dynamics simulation to calculate the satisfaction of the overall separation design indicators and design constraints under the technical specifications of the separation device, including the design parameters of the separated energy quantity n, impulse I, and thrust deviation ΔF.

[0059] Sub-step 62: Conduct elastic dynamics simulation, establish finite element models of the first-stage rocket body, second-stage rocket body, separation device, and related structures for separation action and load bearing, consider elastic deformation, and calculate the satisfaction of overall separation design indicators and design constraints under the design parameters of mass deviation range Δm1, Δm2, centroid deviation range Δc1, Δc2, moment of inertia deviation range ΔI1, ΔI2, thrust deviation ΔF, structural deformation ε1, and structural installation deviation ε2;

[0060] Sub-step 63 involves verifying the agreement between the separation simulation data and the measured data through a prototype test of the separation device, and then correcting the parameters of the separation simulation model based on the test results. The corrected parameters include the simulation step size, contact stiffness, and finite element mesh size.

[0061] The beneficial effects of this invention compared to the prior art are:

[0062] (1) This invention discloses a non-pyrotechnic separation design method for reusable rockets. By analyzing and demonstrating the separation method, separation energy, separation sequence, separation speed index, separation distance and heat flow influence, gas-driven gas supply layout, gas-driven thrust mechanism structure, peak thrust and thrust deviation involved in the separation scheme, it is determined that the first and second stage separation adopts a single cold separation scheme based on gas-driven thrust. Through software simulation analysis based on multi-rigid-body dynamics theory, the limit deviation and safety of interstage separation under fault conditions are analyzed. Furthermore, a simulation calculation study on guided separation considering elastic deformation is carried out, overcoming the difficulties in designing gas-driven thrust separation indexes and gas-driven thrust guided separation considering structural elasticity. The rationality of the design indexes is verified through the lateral load push-out performance test of the prototype.

[0063] (2) This invention discloses a non-pyrotechnic separation design method for reusable rockets, which forms a design process, design elements and indicator system. It is innovative and has good feasibility, realizes the comprehensive coordination of multi-disciplinary design needs, and the design scheme has the advantage of overall optimization. Attached Figure Description

[0064] Figure 1 This is a flowchart illustrating the steps of an interstage non-pyrotechnic separation design method applicable to reusable rockets according to an embodiment of the present invention.

[0065] Figure 2 This is a schematic diagram illustrating the composition and working principle of the air-driven push-impact separation device in an embodiment of the present invention;

[0066] Figure 3a This is a schematic diagram comparing the simulation results and experimental results of the separation distance D in this embodiment of the invention;

[0067] Figure 3b This is a schematic diagram comparing the simulation results and experimental results of the relative separation velocity V in an embodiment of the present invention. Detailed Implementation

[0068] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0069] Example 1

[0070] like Figure 1 As shown in the figure, the interstage non-pyrotechnic separation design method for reusable rockets proposed in this embodiment of the invention includes the following steps:

[0071] Step 1: Based on the top-level requirements for interstage separation in reusable rocket engineering missions, formulate separation scheme evaluation criteria.

[0072] In this embodiment, the top-level requirements for interstage separation in reusable rocket engineering missions are summarized into four evaluation criteria: R1: The first and second stage rocket bodies should separate reliably, allowing the second stage rocket body to continue performing the ascent phase flight mission and the first stage rocket body to continue performing the reentry phase flight mission; R2: The separation scheme meets economic requirements; R3: After the first stage rocket body is recovered, it can be quickly relaunched after undergoing economically affordable testing and maintenance measures; R4: The separation device used for interstage separation has the characteristics of being detectable and measurable.

[0073] Step 2: Determine the input conditions and design constraints for the interstage non-pyrotechnic separation of the reusable rocket as the basis for design.

[0074] In this embodiment, the input conditions include:

[0075] The set masses of the first and second stage arrow bodies are m1 and m2, respectively, and the set center of mass of the first and second stage arrow bodies is c1 = (c x1 c y1 c z1 c2 = (c x2 c y2 c z2 ), the set moment of inertia of the first-stage and second-stage rocket bodies I1 = (I xx1 I yy1 I zz1 ), I2=(I xx2 I yy2 I zz2 The mass deviation ranges of the first-stage and second-stage arrow bodies are Δm1 and Δm2, respectively, and the centroid deviation range of the first-stage and second-stage arrow bodies is Δc1 = (Δc x1 Δc y1 Δc z1 ), Δc2=(Δc x2 Δc y2 Δc z2 The range of rotational inertia deviation between the first-stage and second-stage rocket bodies is ΔI1 = (ΔI xx1 ΔI yy1 ΔI zz1 ), ΔI2=(ΔI xx2 ΔI yy2 ΔI zz2 ); where c x1 c x2 These are the x-coordinates of the center of mass of the first-stage arrow body and the center of mass of the second-stage arrow body in the arrow body coordinate system, respectively. y1 c y1These are the y-coordinates of the center of mass of the first-stage arrow body and the center of mass of the second-stage arrow body in the arrow body coordinate system, respectively. z1 c z1 These are the z-coordinates of the center of mass of the first-stage arrow body and the center of mass of the second-stage arrow body in the arrow body coordinate system, respectively. xx1 I xx2 These are the moments of inertia of the first-stage rocket body about the x-axis of the rocket body coordinate system, and the moments of inertia of the second-stage rocket body about the x-axis of the rocket body coordinate system, respectively. yy1 I yy2 These are the moments of inertia of the first-stage rocket body about the y-axis of the rocket body coordinate system, and the moments of inertia of the second-stage rocket body about the y-axis of the rocket body coordinate system, respectively. zz1 I zz2 These are the moments of inertia of the first-stage rocket body about the z-axis of the rocket body coordinate system, and the moments of inertia of the second-stage rocket body about the z-axis of the rocket body coordinate system, respectively.

[0076] Initial pitch, yaw, and roll attitude angular velocities of the first and second stage components before separation:

[0077] The thrust-time curve T1(t) after the first-stage engine shuts down;

[0078] The thrust-time curve T2(t) of the second-stage engine startup;

[0079] The curve P of the first-stage aerodynamic pressure variation of the second-stage engine with the distance between the first and second-stage rocket bodies 12 (d);

[0080] The curve Q of the first-stage aerodynamic heat flux of the second-stage engine as a function of the distance between the first and second stages of the rocket body. 12 (d);

[0081] Curve of carrying capacity loss as a function of separation time m c (T).

[0082] Design constraints include:

[0083] The loss of carrying capacity due to separation time m c (T)≤100kg;

[0084] The attitude angular velocity after the first stage of the rocket separates is no greater than in, These are the specified values ​​for the pitch, yaw, and roll angular velocities after the first-stage rocket body separates;

[0085] The attitude angular velocity after the second stage of the rocket separates is no greater than in, These are the specified values ​​for the pitch, yaw, and roll angular velocities after the second-stage rocket body separates;

[0086] According to the spatial layout constraints, the available spatial envelope Evp of the separation device is located within the annulus between the minimum available spatial radius R1 and the maximum available spatial radius R2: R1≤Evp≤R2;

[0087] The initial separation gap between the first-stage and second-stage rocket bodies is cl0, and the separation gap during separation must not be less than the preset safety gap cl1. In this embodiment, the initial separation gap cl0 can be 100mm, and the preset safety gap cl1 can be 50mm.

[0088] Step 3: Based on the evaluation criteria and design basis of the separation scheme, determine the separation method, connection unlocking method, separation guidance requirements, and separation energy form.

[0089] In this embodiment, it is necessary to analyze the evaluation criteria and design basis of the separation scheme associated with each item to be determined (separation method, connection unlocking method, separation guidance requirement, and separation energy form), and assign weights to the relevant evaluation criteria and design basis according to their importance to the engineering task and separation process, and establish a weighted evaluation function based on the relevant evaluation criteria and design basis; including the following sub-steps:

[0090] Sub-step 31: Establish the weighted evaluation function f1(R1, R3, P) 12 (d), Q 12 (d) Then, the two separation methods of cold separation and hot separation are evaluated and selected. In this embodiment, cold separation is selected.

[0091] Sub-step 32: Establish a weighted evaluation function f2(R1, R2, R3, cl0, cl1), and then select one of the two separation methods, primary separation and secondary separation, for evaluation. In this embodiment, primary separation is selected.

[0092] Sub-step 33: Determining the connection unlocking method requires establishing a weighted evaluation function f3(R1, R2, R3, R4, Evp, cl0), and then evaluating and selecting one of the two connection unlocking methods, point-type connection unlocking and line-type connection unlocking. In this embodiment, line-type connection unlocking is selected.

[0093] Sub-step 34, determining the separation guidance requirement requires establishing a weighted evaluation function f4(R1, R2, R3, R4, Evp, cl0, cl1) to determine whether guidance is needed during the separation process. In this embodiment, guidance is required.

[0094] Sub-step 35, determining the form of energy separation requires establishing a weighted evaluation function f5(R1, R2, R3, R4, m1, m2, Evp, cl0), and then determining the form of energy separation as one or more of gas drive, hydraulic drive, electric drive, nuclear power or phase change energy drive. In this embodiment, gas drive is selected.

[0095] Step 4: Based on the determined separation method, connection unlocking method, separation guidance requirements, and separation energy form, establish a preliminary separation simulation model. According to the separation scheme evaluation criteria and design basis, determine the overall separation design indicators, including separation time T, separation distance D, relative separation velocity V, separation attitude deviation ΔA, and separation attitude angular velocity.

[0096] In this embodiment, the following sub-steps can be followed:

[0097] Sub-step 41, the separation time T includes the time interval t1 from the shutdown of the first stage engine to the operation of the interstage connection unlocking device and the second stage engine start delay time t2, that is, T = t1 + t2;

[0098] Sub-step 42: Through preliminary separation simulation, determine the acceptable threshold T for the after-effect thrust of the first-stage engine due to inter-stage separation. 1max Furthermore, based on the thrust-time curve after the first-stage engine shuts down, T1(t)≤T 1max Determine the lower limit of the value of t1;

[0099] Sub-step 43, through the design constraint m of carrying capacity c (t1+t2)≤100kg determines the upper limit of the values ​​of t1 and t2, that is, determines the separation time T. max This allows us to determine the range of values ​​for t2;

[0100] Sub-step 44 involves determining the threshold P for accepting aerodynamic pressure from the first-stage rocket body to the second-stage engine through interstage separation. 12max The acceptable threshold Q for the influence of heat flow 12max Solve for P 12 (d)≤P 12max Q 12 (d)≤Q 12max Determine the lower limit D of the separation distance D. min ;

[0101] Sub-step 45: Based on the range of values ​​for t2 and the lower limit of the separation distance D, determine the separation velocity V = D. min The range of values ​​for / t2 is determined, and then, based on the optimization principles of reliability, economy, and minimum energy consumption, the lower limit V of the relative separation rate is set. min The separation time is taken as the upper limit T. max The lower limit of the separation distance is D. min ;

[0102] Sub-step 46: Based on the allowable value of the separation gap and the separation distance, determine the separation attitude deviation ΔA = (cl0 - cl1) / D min and separation attitude angular velocity

[0103] Sub-step 47: Based on the preliminary separation simulation model, check the design constraints under the set overall separation design indicators: the attitude angular velocity of the first-stage rocket body after separation should not exceed [value missing]. and the attitude angular velocity after the second stage of the rocket separates is not greater than The conditions for meeting the requirements are determined, and the constraints of the overall design indicators on the technical indicators of the separation device are identified.

[0104] Step 5: Determine the technical specifications of the separation device, including the amount of energy to be separated (n), impulse (I), and peak thrust (F). max Thrust deviation ΔF, structural deformation ε1, and structural installation deviation ε2.

[0105] In this embodiment, the composition and working principle of the air-driven push-impact separation device are as follows: Figure 2 As shown. The gas-driven push-impact separation device includes a push-impact mechanism and a gas supply system. The gas supply system consists of a gas cylinder and control valves, while the push-impact mechanism consists of a piston cylinder, a piston, and a guide rod. Driven by the high-pressure gas in the gas supply system, the piston of the push-impact mechanism pushes the guide rod along the piston cylinder, providing the relative separation velocity between the first and second stage rocket bodies. Its technical specifications can be determined through the following sub-steps:

[0106] Sub-step 51: The amount of energy to be separated, n, is determined based on the total energy W required for primary and secondary separation and the energy W0 that a single separation unit can provide, i.e., n = W / W0. Initially, frictional losses and various deviations are neglected when calculating n. The primary and secondary separation satisfy the laws of energy conservation and momentum theorem. v1 and v2 are the separation velocities of the first and second stage arrows, respectively. min =v2-v1, m1v1+m2v2=0 is determined, from which the separation velocities v1 and v2 of the first-stage and second-stage rocket bodies and the total separation energy W can be obtained;

[0107] Sub-step 52: Calculate the impulse of a single separation device I = m2v2 / n;

[0108] Sub-step 53, peak thrust F max Constrained by structural bearing capacity, the value is determined based on structural bearing strength and safety factor; and can be determined by the average thrust F of a single separation device. avg =I / t2 Verification of peak thrust F max The rationality;

[0109] In this embodiment, for the gas-driven thrust separation device, the peak thrust provided is the maximum gas pressure P during the thrusting process. max The product of the thrust cross-sectional area and the gas-driven thrust-separation device is a cylindrical structure with radius r, then F max =P max πr2 The external dimensions of the air-driven thrust-separation device are constrained by spatial layout. By selecting the maximum usable radius R2 within the available space envelope, the peak thrust can be reduced, the demand on structural load-bearing capacity can be decreased, and the overall optimal goal can be achieved.

[0110] Sub-step 54 involves determining various deviation design parameters, including thrust deviation ΔF, structural deformation ε1, and structural installation deviation ε2. This requires considering the lateral load F resulting from these deviations during the separation process. h The torque balance equations are established with the first-stage and second-stage rocket bodies as the objects of force respectively:

[0111]

[0112]

[0113] Among them, h1, L F1 L T1 h2, L F2 These represent the lever arms of the lateral load on the first-stage rocket body, the lever arm of the air-driven thrust on the first-stage rocket body, the lever arm of the after-effect thrust of the first-stage engine on the first-stage rocket body, the lever arm of the lateral load on the second-stage rocket body, and the lever arm of the air-driven thrust on the second-stage rocket body, respectively; F represents the thrust of the separation device; These represent the separation attitude angular velocities of the first-stage and second-stage rocket bodies, respectively. for The vector synthesis result. Based on the stated moment balance equation, a preliminary calculation is performed to determine the lateral load F. h The values ​​of thrust deviation ΔF are used to calculate the separation attitude deviation ΔA and separation attitude angular velocity using a separation simulation model. The structural deformation ε1 and structural installation deviation ε2 are determined based on the satisfaction of design constraints.

[0114] Step 6: Under the design parameters of the separation device's technical specifications, verify the overall separation design parameters and correct the separation simulation model through multibody dynamics simulation and separation principle prototype testing;

[0115] In this embodiment, the following sub-steps can be followed:

[0116] Sub-step 61: First, perform rigid body dynamics simulation to calculate the overall design parameters, including separation time T, separation distance D, relative separation velocity V, separation attitude deviation ΔA, and separation attitude angular velocity, under the technical specifications of the separation device, such as the number of separated energy sources n, impulse I, and thrust deviation ΔF. And the satisfaction of design constraints;

[0117] Sub-step 62, then conduct elastic dynamics simulation, establish finite element models of the first-stage rocket body, second-stage rocket body, separation device, and related structures for separation action and load bearing, consider elastic deformation, and calculate various deviations, including mass deviation ranges Δm1, Δm2, and centroid deviation range Δc1 = (Δc x1 Δc y1 Δc z1 ), Δc2=(Δc x2 Δc y2 Δc z2 ), the range of rotational inertia deviation ΔI1=(ΔI xx1 ΔI yy1 ΔI zz1 ), ΔI2=(ΔI xx2 ΔI yy2 ΔI zz2 Given the design parameters of thrust deviation ΔF, structural deformation ε1, and structural installation deviation ε2, the overall design indices are separation time T, separation distance D, relative separation velocity V, separation attitude deviation ΔA, and separation attitude angular velocity. And the satisfaction of design constraints;

[0118] Sub-step 63 concludes by testing a prototype of the separation device to verify the agreement between the separation simulation data and the measured data, and then adjusting the parameters of the separation simulation model based on the test results. In this embodiment, the adjusted parameters include the simulation step size, contact stiffness, and finite element mesh size.

[0119] In this embodiment, as Figure 3a and Figure 3b As shown, the simulation results of the non-pyrotechnic separation design method applicable to reusable rockets are in good agreement with the experimental results, indicating that the design method is correct and reasonable.

[0120] Step 7: Repeat steps 4 to 6 to iterate and complete the closed-loop design of the technical indicators of the separation device and the overall design indicators of the separation. Based on the set overall performance requirements, select the optimal closed-loop design scheme.

[0121] In summary, this invention analyzes and demonstrates the separation methods, energy sources, timing, speed parameters, influence of separation distance and heat flow, gas-driven gas supply layout, structural form of the gas-driven thrust mechanism, peak thrust, and thrust deviation involved in the separation scheme. It determines that the first and second stage separation adopts a single-stage cold separation scheme based on gas-driven thrust. Through software simulation analysis based on multi-rigid-body dynamics theory, it examines the limit deviations and the safety of inter-stage separation under fault conditions. Furthermore, it conducts simulation calculations for guided separation considering elastic deformation, overcoming difficulties such as the design of gas-driven thrust separation parameters and the consideration of structural elasticity in gas-driven thrust guided separation. The rationality of the design parameters is verified through lateral load ejection performance tests on the prototype.

[0122] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0123] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A non-pyrotechnic separation design method applicable to reusable rockets, characterized in that, Includes the following steps: Step 1: Based on the top-level requirements for interstage separation in reusable rocket engineering missions, formulate separation scheme evaluation criteria; Step 2: Determine the input conditions and design constraints for the interstage non-pyrotechnic separation of the reusable rocket as the design basis; Step 3: Based on the evaluation criteria and design basis of the separation scheme, determine the separation method, connection unlocking method, separation guidance requirements, and separation energy form; Step 4: Based on the determined separation method, connection unlocking method, separation guidance requirements, and separation energy form, establish a preliminary separation simulation model. According to the separation scheme evaluation criteria and design basis, determine the overall separation design indicators, including separation time T, separation distance D, relative separation speed V, and separation attitude deviation. Separation attitude angular velocity ; Step 5: Determine the technical specifications of the separation device, including the amount of energy to be separated (n), impulse (I), and peak thrust. Thrust deviation Structural deformation Structural installation deviation ; Step 6: Under the design parameters of the separation device's technical specifications, verify the overall separation design parameters and correct the separation simulation model through multibody dynamics simulation and separation principle prototype testing; specifically including: Sub-step 61 involves conducting rigid body dynamics simulations to calculate the technical specifications of the separation device, including the amount of separated energy (n), impulse (I), and thrust deviation. Given the design parameters, determine the satisfaction of the overall design indicators and design constraints. Sub-step 62: Conduct elastic dynamics simulation, establish finite element models of the first-stage rocket body, second-stage rocket body, separation device, and related structures for separation action and load bearing, consider elastic deformation, and calculate the mass deviation range of the first-stage and second-stage rocket bodies. , The range of center of gravity deviation between the first-stage and second-stage arrow bodies , Range of rotational inertia deviation between the first-stage and second-stage rocket bodies , Thrust deviation Structural deformation Structural installation deviation Given the design parameters, determine the satisfaction of the overall design indicators and design constraints. Sub-step 63: Through the prototype test of the separation device, verify the consistency between the separation simulation data and the measured data, and correct the parameters of the separation simulation model based on the test results. The corrected parameters include simulation step size, contact stiffness, and finite element mesh size. Step 7: Repeat steps 4 to 6 to iterate and complete the closed-loop design of the technical indicators of the separation device and the overall design indicators of the separation. Based on the set overall performance requirements, select the optimal closed-loop design scheme.

2. The interstage non-pyrotechnic separation design method for reusable rockets according to claim 1, characterized in that, The evaluation criteria for the separation scheme described in step 1 specifically include: R1: The first and second stage rocket bodies can be reliably separated, allowing the second stage rocket body to continue performing the ascent phase flight mission and the first stage rocket body to continue performing the reentry phase flight mission. R2: The separation scheme meets the economic requirements; R3: After the first-stage rocket body is recovered, and after economically feasible testing and repair measures, it can be quickly organized for relaunch; R4: Separation devices used for interstage separation are characterized by being detectable and measurable.

3. The interstage non-pyrotechnic separation design method for reusable rockets according to claim 2, characterized in that, The input conditions described in step 2 include: The set mass of the first and second stage arrow bodies , The center of mass of the first and second stage arrow bodies , The set rotational inertia of the first and second stage arrow bodies , Mass deviation range of the first and second stage arrow bodies , The range of the center of gravity deviation between the first-stage and second-stage arrow bodies , The range of rotational inertia deviation between the first-stage and second-stage rocket bodies , ; Initial pitch, yaw, and roll attitude angular velocities of the first and second stage components before separation: ; First-stage engine shutdown after-effect thrust-time curve ; Second-stage engine start-up thrust-time curve ; Curve of first-stage aerodynamic pressure variation of the second-stage engine with distance between the first and second-stage rocket bodies ; Curve of first-stage aerodynamic heat flux variation of the second-stage engine with distance between the first and second stages of the rocket body ; Curve of carrying capacity loss as a function of separation time .

4. The interstage non-pyrotechnic separation design method for reusable rockets according to claim 3, characterized in that, The design constraints mentioned in step 2 include: Capacity loss due to separation time ; The attitude angular velocity after the first stage of the rocket separates is no greater than ,in, These are the specified values ​​for the pitch, yaw, and roll angular velocities after the first-stage rocket body separates; The attitude angular velocity after the second stage of the rocket separates is no greater than ,in, These are the specified values ​​for the pitch, yaw, and roll angular velocities after the second-stage rocket body separates; Based on spatial layout constraints, the available spatial envelope Evp of the separation device lies within the minimum available spatial radius. and the maximum available radius of space Inside the rings between: ; The initial separation gap between the first-stage and second-stage rocket bodies is During the separation process, the separation gap must not be less than the preset safety gap. .

5. The interstage non-pyrotechnic separation design method for reusable rockets according to claim 4, characterized in that, The method for determining the separation method in step 3 is as follows: The analysis relates the evaluation criteria and design basis to the separation method, and assigns weights to the relevant criteria and design basis according to their importance to the engineering task and separation process. A weighted evaluation function based on these criteria and design basis is then established, including: Establish a weighted evaluation function Then, an evaluation is conducted on the two separation methods of cold separation and hot separation to select one; Then, a weighted evaluation function is established. Then, one of the two separation methods, primary separation and secondary separation, is evaluated and selected; The method for determining the connection unlocking method is as follows: Establish a weighted evaluation function Then, one of the two connection unlocking methods, point-to-point connection unlocking and line-to-line connection unlocking, is evaluated and selected. The method for determining the separation-oriented requirements is as follows: Establish a weighted evaluation function This allows us to determine whether guidance is needed during the separation process; The method for determining the form of separated energy is as follows: Establish a weighted evaluation function Furthermore, it is determined that the energy source for separation is one or more of the following: gas drive, hydraulic drive, electric drive, nuclear power, or phase change energy drive.

6. The interstage non-pyrotechnic separation design method for reusable rockets according to claim 5, characterized in that, The separation method is selected as cold separation or single separation; the connection unlocking method is selected as linear connection unlocking; the separation guidance requirement is selected as guidance required; and the separation energy form is selected as gas drive.

7. The interstage non-pyrotechnic separation design method for reusable rockets according to claim 5, characterized in that, The separation time T mentioned in step 4 includes: the time interval from the shutdown of the first-stage engine to the operation of the interstage connection unlocking device. and second-stage engine start-up delay time , Preliminary separation simulations were used to determine the acceptable threshold for the after-effect thrust of the first-stage engine due to interstage separation. Furthermore, based on the thrust-time curve after the first-stage engine shuts down... Sure The lower limit of the value; through the design constraints of carrying capacity. Sure and The upper limit of the value is used to obtain the upper limit of the separation time. to determine The range of values ​​for; The separation distance D: the threshold for accepting aerodynamic pressure from the first-stage rocket body on the second-stage engine due to interstage separation. Acceptable threshold of heat flow influence Solve , Determine the lower limit of the separation distance D ; The relative separation velocity V: according to The relative separation velocity is determined by the range of values ​​for and the lower limit of the separation distance D. The range of values ​​for; The separation attitude deviation and separation attitude angular velocity Determine the separation attitude deviation based on the allowable value of the separation gap and the lower limit of the separation distance. and separation attitude angular velocity .

8. The interstage non-pyrotechnic separation design method for reusable rockets according to claim 7, characterized in that, Based on the optimization principles of reliability, economy, and minimum energy consumption, a lower limit is set for the relative separation rate. The separation time is taken as the upper limit. Take the lower limit of the separation distance. ; Based on the preliminary separation simulation model, the design constraints under the set overall separation design parameters are checked: the attitude angular velocity of the first-stage rocket body after separation should not exceed [value missing]. and the attitude angular velocity after the second stage of the rocket separates is not greater than The conditions for meeting the requirements are determined, and the constraints of the overall design indicators on the technical indicators of the separation device are identified.

9. The interstage non-pyrotechnic separation design method for reusable rockets according to claim 8, characterized in that, The energy quantity n to be separated in step 5 is based on the total energy required for the first and second stage separation. and the energy that a single separation unit can provide Sure: When calculating n initially, frictional losses and various deviations are neglected. The total energy required for primary and secondary separation is... , , These are the separation velocities of the first and second stage arrow bodies, respectively, according to... , Sure; The impulse I is calculated as: the impulse of a single separation device. ; The peak thrust It is determined based on the structural bearing capacity and safety factor; The thrust deviation Structural deformation Structural installation deviation The determination takes into account the lateral load caused by various deviations during the separation process. The torque balance equations are established with the first-stage and second-stage rocket bodies as the objects of force respectively: in, These represent the lever arms of the lateral load on the first-stage rocket body, the lever arms of the air-driven thrust on the first-stage rocket body, the lever arms of the after-effect thrust of the first-stage engine on the first-stage rocket body, the lever arms of the lateral load on the second-stage rocket body, and the lever arms of the air-driven thrust on the second-stage rocket body, respectively. Indicates the thrust of the separation device; , These represent the separation attitude angular velocities of the first-stage and second-stage rocket bodies, respectively. for , The vector synthesis result; Preliminary calculations are performed based on the torque balance equations to determine the lateral load. and thrust deviation The value of is then used to calculate the separation attitude deviation using a separation simulation model. and separation attitude angular velocity The amount of structural deformation is determined based on the satisfaction of design constraints. Structural installation deviation The determination.

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