阅读说明：本技术 一种垂直回收演示验证火箭飞行时序设计方法 (Design method for vertical recovery demonstration and verification of rocket flight time sequence ) 是由 杨跃 朱佩婕 罗庶 马道远 梁家伟 赵学光 李金梅 李钧 岳小飞 韩明晶 龚习 于 2021-08-17 设计创作，主要内容包括：本发明涉及一种垂直回收演示验证火箭飞行时序设计方法。通过对飞行时间进行分段设计,匹配各对应高度段的轴向飞行过载,使得各对应高度段的轴向飞行过载适宜垂直回收验证火箭的验证飞行,具体设计方法是：通过按时序对发动机进行推力调节,实现箭体轴向飞行过载的交错变化,为垂直回收演示验证火箭飞行全程提供适宜的轴向飞行过载,最终可以实现垂直受控着陆回收。本方法保证演示验证火箭全程都具有适当的飞行过载,规避了低过载下贮箱推进剂管理的复杂问题；规避了发动机二次点火的复杂问题；不需研制复杂的推进剂管理系统；为可回收关键技术验证提供了较适宜的飞行环境；为垂直回收演示验证火箭的总体设计提供了有力支撑。(The invention relates to a design method for demonstrating and verifying rocket flight time sequence through vertical recovery. The flight time is designed in sections, and the axial flight overload of each corresponding altitude section is matched, so that the axial flight overload of each corresponding altitude section is suitable for the verification flight of the vertical recovery verification rocket, and the specific design method comprises the following steps: the thrust of the engine is adjusted according to the sequence, so that the staggered change of the axial flying overload of the rocket body is realized, the proper axial flying overload is provided for the whole process of the vertical recovery demonstration and verification rocket flying, and the vertical controlled landing recovery can be finally realized. The method ensures that the rocket is demonstrated and verified to have proper flight overload in the whole process, and avoids the complex problem of storage tank propellant management under low overload; the complex problem of secondary ignition of the engine is avoided; a complex propellant management system does not need to be developed; a more suitable flight environment is provided for recoverable key technology verification; powerful support is provided for the overall design of the vertical recovery demonstration and verification rocket.)

1. A vertical recovery demonstration rocket flight time sequence design method is characterized in that flight time is designed in a segmented mode, and axial flight overload of each corresponding altitude section is matched, so that the axial flight overload of each corresponding altitude section is suitable for the verification flight of a vertical recovery verification rocket, and the specific design method is as follows:

the thrust of the engine is adjusted according to the time sequence, so that the staggered change of the axial flying overload of the rocket body is realized, the proper axial flying overload is provided for the whole process of the vertical recovery demonstration and verification of the rocket flying, and the vertical controlled landing recovery can be finally realized;

the flight time is segmented into a takeoff ascending section, a first deceleration ascending and then acceleration descending section and a deceleration descending section, the takeoff ascending section corresponds to a flight height h1, the first deceleration ascending and then acceleration descending section corresponds to a flight height h2, the deceleration descending section corresponds to a flight height h3, thrust adjustment is performed on the engine in each stage, the takeoff ascending section, the first deceleration ascending and then acceleration descending section and the deceleration descending section are determined according to thrust-quality-height-overload iterative calculation, the thrust adjustment is performed on the engine in each stage, and staggered change of rocket body axial flight overload is achieved.

2. The vertical recovery demonstration rocket flight timing sequence design method according to claim 1, characterized in that the specific principle of realizing staggered change of rocket body axial flight overload is as follows:

for the takeoff and ascending section of the rocket, the size is not too large or too small, the value n1 is 1.1g-1.3g, and if the size is too large, the ascending height of the rocket is too high, because the thrust adjusting amplitude of an engine is limited, the engine cannot be recovered, and if the size is too small, the risk of too slow departure exists;

for the section of the rocket which is decelerated and ascended firstly and then accelerated and descends, the section is not too large or too small, but the section is smaller than the section of the rocket which is ascended, the value n2 is 0.6g-0.9g, if the section is too large, the rocket needs to be decelerated for a longer time, the mass of the consumed propellant is increased, because the lower limit of thrust adjustment of the engine is limited, finally, the gravity of the rocket is smaller than the lower limit of thrust adjustment of the engine, the aircraft cannot descend, and if the section is too small, the thrust adjustment range of the engine is limited and cannot be realized;

for the deceleration descending section of the rocket, the deceleration descending section is not too large or too small, but the deceleration descending section is larger than the flying ascending section, the value n3 is 1.1g-1.4g, if the deceleration descending section is too large, the rocket decelerates faster, the descending speed returns to zero fast, the aircraft can accelerate and ascend reversely, and finally cannot land, if the deceleration descending section is too small, the deceleration performance is weaker, the speed of the aircraft cannot be reduced to 0 when the altitude returns to zero, and the requirement of the landing speed cannot be met.

3. The method for designing the flight time sequence of the vertical recovery demonstration rocket according to claim 2, wherein the specific time sequence steps are designed as follows:

step 1, after an ignition signal is sent out by a demonstration and verification rocket main engine at the time of T0, carrying out demonstration and verification rocket body departure judgment at the time of T1 at intervals of preset time T1, and sending a continuous working or emergency shutdown signal to the demonstration and verification rocket main engine;

step 11, if the arrow body is judged not to normally leave the platform at the time T1, a preset time T2 is set, the main engine executes an emergency shutdown program at the time T2, and the preset time T1 is smaller than the preset time T2;

step 12, if the rocket body is judged to be normally off the platform, the main engine continues to normally work, the flying height is judged at the time of T3 at a preset time T3, if the flying height does not reach the preset height h1, the thrust of the engine is kept unchanged, the rocket continuously flies according to the overload n1 which is not less than the preset overload, if the flying height reaches the preset height h1, the thrust is reduced at the time of T4 by the main engine at a preset time T4, and the rocket is enabled to be demonstrated and verified to slow down and ascend;

step 2, after the demonstration and verification rocket reaches a ballistic vertex, the rocket body starts to accelerate and descend, the rocket overload is kept smaller than n2, the altitude is judged at the time of T5 at intervals of preset time T5, if the rocket does not reach the preset altitude h2, the thrust of the main engine is kept unchanged, the current overload is continued to fly, if the rocket reaches the preset altitude h2, the thrust of the main engine is increased at the time of T6 at intervals of preset time T6, and the demonstration and verification rocket is decelerated and descends; when the height is judged to be smaller than the program preset value h2, the thrust of the main engine is increased, and the rocket body flying overload is kept to be larger than n3 through thrust adjustment;

and 3, after the moment T6, the demonstration and verification rocket enters a vertical landing final guide section, the main engine adjusts the thrust and the vector direction in a small amplitude mode while keeping the flying overload greater than n3, the rocket body descends in a deceleration mode at a preset time T7, the flying height is judged at the moment T7, when the flying height is smaller than a program preset value h3, the demonstration and verification rocket main engine is closed, the rocket body is recovered in a vertical landing mode, and the vertical landing demonstration and verification flying is completed.

4. The method for designing the flight sequence of a vertical recovery demonstration rocket according to claim 3, wherein the method comprises the following steps: t1 is 3s-5 s.

5. The method for designing the flight sequence of a vertical recovery demonstration rocket according to claim 3, wherein the method comprises the following steps: t2 is 5s-7 s.

6. The method for designing the flight sequence of a vertical recovery demonstration rocket according to claim 3, wherein the method comprises the following steps: t3 is 30s-35 s.

7. The method for designing the flight sequence of a vertical recovery demonstration rocket according to claim 3, wherein the method comprises the following steps: t4 is 35s-40 s.

8. The method for designing the flight sequence of a vertical recovery demonstration rocket according to claim 3, wherein the method comprises the following steps: t5 is 75s-80 s.

9. The method for designing the flight sequence of a vertical recovery demonstration rocket according to claim 3, wherein the method comprises the following steps: t6 is 80s-85 s.

10. The method for designing the flight sequence of a vertical recovery demonstration rocket according to claim 3, wherein the method comprises the following steps: t7 is 100s-120 s.

Technical Field

The invention relates to the field of reusable rockets, in particular to a design method for demonstrating and verifying a flight time sequence of a rocket through vertical recovery.

Background

Since the introduction of the concept of VTOL vehicles, reusable rocket designs have received a great deal of attention in the industry. Compared with a disposable rocket, the reusable rocket not only needs to consider the ascending section, but also needs to consider the returning section, and the whole flying process is wide in airspace and speed range, complex and changeable in flying environment, strong in external disturbance and uncertainty, large in technical difficulty and high in development risk. In addition, after a main engine of a traditional carrier rocket is shut down, the residual propellant in the storage tank can be caused to obviously shake due to severe reduction of axial overload, the risk that liquid impacts the front bottom of the storage tank exists, and the residual propellant and pressurized gas are fully mixed in the storage tank due to the fact that no overload flying working condition exists in the following aircraft in the process of sliding, the propellant in a power transmission pipeline has the risk of air entrainment, the reliability of the engine can be reduced when the engine is started for the second time, and the flying safety of the aircraft is influenced.

Therefore, in order to break through the key technology of the vertical take-off and landing rocket and effectively reduce the development cost, the overall timing design of the vertical take-off and landing demonstration and verification rocket needs to be developed to avoid the problems.

Disclosure of Invention

In order to solve the defects of the prior art, the invention aims to provide a time sequence design method of a vertical take-off and landing demonstration and verification rocket, which ensures that the demonstration and verification rocket has proper flight overload in the whole process, avoids the complex problem of storage tank propellant management under low overload, avoids the complex problem of secondary ignition of an engine, does not need to develop a complex propellant management system, reduces the development cost of a vertical recovery verification rocket, and provides a proper flight environment for recoverable key technology verification.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a vertical recovery demonstration rocket flight time sequence design method is characterized in that flight time is designed in a segmented mode, and axial flight overload of each corresponding altitude section is matched, so that the axial flight overload of each corresponding altitude section is suitable for the verification flight of a vertical recovery verification rocket, and the specific design method is as follows:

the thrust of the engine is adjusted according to the time sequence, so that the staggered change of the axial flying overload of the rocket body is realized, the proper axial flying overload is provided for the whole process of the vertical recovery demonstration and verification of the rocket flying, and the vertical controlled landing recovery can be finally realized;

the flight time is segmented into a takeoff ascending section, a first deceleration ascending and then acceleration descending section and a deceleration descending section, the takeoff ascending section corresponds to a flight height h1 (the height can be obtained according to the flight time and overload), the first deceleration ascending and then acceleration descending section corresponds to a flight height h2 (the height is obtained according to the flight time and overload level accumulation of each section), the deceleration descending section corresponds to a flight height h3, the engine is subjected to thrust adjustment in each stage, specifically, the takeoff ascending section, the first deceleration ascending and then acceleration descending section and the deceleration descending section are determined according to thrust-mass-height-overload iterative calculation, the magnitude of the thrust adjustment (namely, the mass of the propellant) is carried out on the engine in each stage, and the staggered change of the rocket body axial flight overload is realized.

Further, the specific principle of realizing the staggered change of the rocket body axial flying overload is as follows:

for the takeoff and ascending section of the rocket, the size is not too large or too small, the value n1 is 1.1g-1.3g, and if the size is too large, the ascending height of the rocket is too high, because the thrust adjusting amplitude of an engine is limited, the engine cannot be recovered, and if the size is too small, the risk of too slow departure exists;

for the section of the rocket which is decelerated and ascended firstly and then accelerated and descends, the section is not too large or too small, but the section is smaller than the section of the rocket which is ascended, the value n2 is 0.6g-0.9g, if the section is too large, the rocket needs to be decelerated for a longer time, the mass of the consumed propellant is increased, because the lower limit of thrust adjustment of the engine is limited, finally, the gravity of the rocket is smaller than the lower limit of thrust adjustment of the engine, the aircraft cannot descend, and if the section is too small, the thrust adjustment range of the engine is limited and cannot be realized;

for the deceleration descending section of the rocket, the deceleration descending section is not too large or too small, but the deceleration descending section is larger than the flying ascending section, the value n3 is 1.1g-1.4g, if the deceleration descending section is too large, the rocket decelerates faster, the descending speed returns to zero fast, the aircraft can accelerate and ascend reversely, and finally cannot land, if the deceleration descending section is too small, the deceleration performance is weaker, the speed of the aircraft cannot be reduced to 0 when the altitude returns to zero, and the requirement of the landing speed cannot be met.

Further, the specific timing steps are designed as follows:

step 1, after an ignition signal is sent out by a demonstration and verification rocket main engine at the time of T0, carrying out demonstration and verification rocket body departure judgment at the time of T1 at intervals of preset time T1, and sending a continuous working or emergency shutdown signal to the demonstration and verification rocket main engine;

step 11, if the arrow body is judged not to normally leave the platform at the time T1, a preset time T2 is set, the main engine executes an emergency shutdown program at the time T2, and the preset time T1 is smaller than the preset time T2;

step 12, if the rocket body is judged to be normally off the platform, the main engine continues to normally work, the flying height is judged at the time of T3 at a preset time T3, if the flying height does not reach the preset height h1, the thrust of the engine is kept unchanged, the rocket continuously flies according to the overload n1 which is not less than the preset overload, if the flying height reaches the preset height h1, the thrust is reduced at the time of T4 by the main engine at a preset time T4, and the rocket is enabled to be demonstrated and verified to slow down and ascend;

step 2, after the demonstration and verification rocket reaches a ballistic vertex, the rocket body starts to accelerate and descend, the rocket overload is kept smaller than n2, the altitude is judged at the time of T5 at intervals of preset time T5, if the rocket does not reach the preset altitude h2, the thrust of the main engine is kept unchanged, the current overload is continued to fly, if the rocket reaches the preset altitude h2, the thrust of the main engine is increased at the time of T6 at intervals of preset time T6, and the demonstration and verification rocket is decelerated and descends; when the height is judged to be smaller than the program preset value h2, the thrust of the main engine is increased, and the rocket body flying overload is kept to be larger than n3 through thrust adjustment;

and 3, after the moment T6, the demonstration and verification rocket enters a vertical landing final guide section, the main engine adjusts the thrust and the vector direction in a small range while keeping the flying overload greater than n3, the landing speed and the attitude of the rocket body are controlled, the landing speed precision and the attitude precision meet the design index requirements of a landing system, the rocket body descends in a deceleration mode, the flying height is judged at the moment T7 at intervals of preset time T7, when the flying height is smaller than a program preset value h3, the main engine of the demonstration and verification rocket is closed, the rocket body is recovered in a vertical landing mode, and the vertical take-off and landing demonstration and verification flying is completed.

Further, t1 is 3s-5 s.

Further, t2 is 5s-7 s.

Further, t3 is 30s-35 s.

Further, t4 is 35s-40 s.

Further, t5 is 75s-80 s.

Further, t6 is 80s-85 s.

Further, t7 is 100s-120 s.

In general, the above technical solutions contemplated by the present invention can achieve the following beneficial effects:

according to the time sequence designed by the invention, in the takeoff ascending section, the axial flying overload value n1 of the rocket body is between 1.1g and 1.3 g; firstly, the rocket body is decelerated and ascended and then accelerated to descend, and the axial flying overload value n2 of the rocket body is 0.6g-0.9 g; in the deceleration descending section, the axial flying overload value n3 of the rocket body is 1.1g-1.4 g; the rocket is guaranteed to have proper flight overload in the whole course of demonstration and verification, and the complex problem of storage tank propellant management under low overload is solved; the complex problem of secondary ignition of the engine is avoided. Without the need to develop complex propellant management systems. The development cost of the vertical recovery verification rocket is reduced. And a more suitable flight environment is provided for recoverable key technology verification. Powerful support is provided for the overall design of the vertical recovery demonstration and verification rocket.

Drawings

FIG. 1 is a flow chart of a method for demonstrating and verifying rocket flight timing design through vertical recovery according to the invention.

FIG. 2 is a timing diagram for demonstrating rocket thrust adjustment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. The specification and examples are exemplary only.

The flight time sequence design method is used for vertically recovering a demonstration and verification rocket (hereinafter referred to as the rocket for short), and the rocket mainly comprises a structural system (a main cabin body), a power system containing a main engine (containing propellant), a control system (containing time sequence control software), a measurement system and the like, wherein the measurement system is used for acquiring rocket body flight state information, navigation position information and the like in real time. After the main engine is ignited after the rocket starts flying, whether the rocket body is off the platform is judged according to a preset off-platform detection program, and a signal for continuing working or emergency shutdown is sent to the main engine. Whether the preset time for the destaging is judged is generally s5-7 s. After the rocket is successfully lifted off the platform, the rocket continuously flies according to the designed time sequence. The thrust of the main engine acts directly on the rocket.

As shown in fig. 1, the invention provides a design method for a vertical recovery demonstration rocket flight time sequence, which is characterized in that the flight time is designed in sections and the axial flight overload of each corresponding altitude section is matched, so that the axial flight overload of each corresponding altitude section is suitable for the verification flight of a vertical recovery verification rocket, and the specific design method comprises the following steps:

the thrust of the engine is adjusted according to the flight time sequence, so that the staggered change of the axial flight overload of the rocket body is realized, the proper axial flight overload is provided for the vertical recovery demonstration and verification of the whole flight process of the rocket, and the vertical controlled landing recovery can be finally realized;

the flight time is divided into a takeoff ascending section, a first deceleration ascending and then acceleration descending section and a deceleration descending section, the takeoff ascending section corresponds to a flight height h1, the first deceleration ascending and then acceleration descending section corresponds to a flight height h2, the deceleration descending section corresponds to a flight height h3, the thrust of the engine is adjusted in each stage, the takeoff ascending section, the first deceleration ascending and then acceleration descending section and the deceleration descending section are determined according to the iterative calculation of thrust-quality (referring to the quality of the rocket) and height-overload, the thrust is adjusted in each stage, namely the thrust is adjusted by adjusting the combustion quality of the propellant, because the propellant in the rocket is consumed in the flying process, the change of the mass of the propellant can cause the change of the quality of the rocket, the adjustment of the thrust of the engine in each stage is determined according to the iterative calculation of the thrust-quality-height-overload, to realize staggered change of the axial flying overload of the rocket body. The heights h1 and h2 are obtained by iterative operation by adopting the following conventional formula, wherein the thrust-mass-height-overload is as follows:

A_p＝M_FG2FSM_JT2FG[P/M；0；0]p is thrust, M is rocket body mass at solving time (rocket body mass changes due to propellant mass change), and M is_JT2FGFor converting an arrow coordinate system into a matrix of an emission coordinate system, A_pThe acceleration generated by the thrust under the emission coordinate system. AK gfs + Acof + Acf + A_p+ AN, AK is the sum acceleration that the arrow body receives under the emission coordinate system, gfs is the gravitational acceleration, Acof is the involved acceleration, Acf is the Coriolis acceleration, AN is the acceleration that aerodynamic force produces under the emission coordinate system, N ═ A_p+A_NN is an overload, V_fs(i+1)＝V_fs(i)+t_stepA_k(i +1) is the calculation period, V_fs(i) For calculating the speed of the cycle, V_fs(i +1) is the speed of the present tamper period; r_fs(i+1)＝R_fs(i)+t_stepV_fs(i+1)，R_fs(i) For the position of the last calculation cycle, R_fs(i +1) is the position of the calculation cycle; h (i +1) ═ M_FS2DX(R_fs(i+1)+R_0fs)|-R_0dx(i +1), H (i +1) is the height of the calculation period (i.e. corresponding to H1 and H2 values), R_0fsAs the position of the emission point in the emission coordinate system, M_FS2DXFor transforming the emitting coordinate system into a ground-centered coordinate system matrix, R_0dx(i +1) is the distance from the corresponding surface location to the geocentric.

However, the height of h3 judged by final landing is related to the guidance strategy and navigation error precision of the arrow body and the landing speed born by the landing leg, and finally the result of h3 value is obtained by comprehensive analysis and is related to the index level of hardware, such as the design index of the bearing capacity of the landing buffer mechanism.

Further, the specific principle of realizing the staggered change of the rocket body axial flying overload is as follows:

after the rocket is successfully lifted off the platform, the thrust of a main engine is not adjusted in the rising section of the takeoff of the rocket, the axial flying overload of the rocket body is not too large or too small, the rocket body continuously flies according to the preset overload n1, the value of n1 is 1.1g, the rising height of the rocket is too high if the value is too large, the thrust adjusting amplitude of the engine is limited, the rocket cannot be recovered, and the risk of too slow lifting exists if the value is too small; in another embodiment n1 is 1.3g and in yet another embodiment n1 is 1.2 g.

The flying height h1 of the rocket is continuously judged in the flying process, when h1 is larger than a program preset value, the thrust of a main engine is reduced, the flying overload of the rocket body is kept smaller than n2 through thrust adjustment, the rocket body is not too large or too small for the descending section of the rocket which is decelerated and ascended first and then accelerated, but is smaller than the ascending section of the rocket, the value of n2 is 0.6g, the value of n2 is not too large, if the value of n2 is too large, the rocket needs to be decelerated for a longer time, the mass of the propellant is consumed to be increased, because the lower limit of the thrust adjustment of the engine is limited, the gravity of the rocket is smaller than the lower limit of the thrust adjustment of the engine finally, the aircraft cannot descend, and if the value of h1 is too small, the thrust adjustment range of the engine is limited and cannot be realized; in another embodiment n2 is 0.9g and in yet another embodiment n2 is 0.75 g.

The flying rocket is in a deceleration ascending state firstly, flies in an acceleration descending state after the top point of the ballistic trajectory flight (the top point can be judged by the rocket body navigation information), the flying process continuously judges the flying height h2 of the rocket (the height h2 point is the thrust adjusting point in the falling process), when h2 is less than the program preset value, the flying is judged to return to the deceleration starting point, the thrust of the main engine is increased, through thrust adjustment, the flying overload of the rocket body is kept to be larger than n3, n3 is 1.1g, at the moment, the rocket body is not too large or too small for the deceleration descending section of the rocket, however, the value n3 is 1.1g, if the value is too large, the rocket decelerates faster, the descent speed returns to zero quickly, the aircraft ascends in a reverse acceleration mode, and finally cannot land, if the value is too small, the deceleration performance is weak, the speed of the aircraft cannot be reduced to 0 when the altitude returns to zero, and the requirement of the landing speed cannot be met. And while keeping the flight overload, the thrust and the vector propulsion direction of the engine are adjusted in a small amplitude, the landing speed and the landing attitude of the arrow body are controlled, and the landing speed precision and the landing attitude precision are ensured to meet the design index requirements of a landing system. And when the rocket body decelerates and descends, continuously judging the flying height h3 of the rocket, and when h3 is smaller than a program preset value, closing the main engine of the rocket, vertically landing and recovering the rocket body, and finishing vertical take-off and landing demonstration and verification flight. In another embodiment n3 is 1.4g and in yet another embodiment n3 is 1.25 g.

As shown in fig. 2, the T1-T7 are calculated from the ignition T0 at predetermined time intervals, and further, the specific timing steps are designed as follows:

step 1, after an ignition signal is sent out by a demonstration and verification rocket main engine at the time of T0, carrying out demonstration and verification rocket body departure judgment at the set time of T1 at the interval of preset time T1 and T1 of 3s, and sending a continuous working or emergency shutdown signal to the demonstration and verification rocket main engine; in another embodiment t1 takes the value 5s, and in yet another embodiment t1 takes the value 4 s.

Step 11, if the arrow body is judged not to normally leave the platform at the time T1, the interval preset time T2 is set, T2 is 5s, the main engine executes an emergency shutdown program at the time T2, and the interval preset time T1 is smaller than the interval preset time T2; in another embodiment t2 takes the value 7s, and in yet another embodiment t2 takes the value 6 s.

Step 12, if the rocket body is judged to be normally off the platform, the main engine continues to normally work, the rocket body is kept to accelerate and ascend, the flying height is judged at the T3 time within the preset time T3, T3 is 30s, if the flying height does not reach the preset height h1, the thrust of the engine is kept unchanged, the rocket continuously flies according to the condition that the overload is not less than the preset overload n1, n1 is 1.3g, if the preset height h1 is reached, the thrust is reduced at the T4 interval within the preset time T4 for 35s, and the main engine enables the demonstration and verification rocket to decelerate and ascend at the T4 time; in another embodiment t3 takes the value 32.5s, and in yet another embodiment t3 takes the value 35 s. In another embodiment t4 takes the value 40s, and in yet another embodiment t4 takes the value 37.5 s. In another embodiment n1 is 1.2g and in yet another embodiment n1 is 1.1 g.

Step 2, after the demonstration and verification rocket reaches a ballistic vertex, the rocket body starts to accelerate and descend, the rocket overload is kept smaller than n2, n2 is 0.9g, the preset time T5 is spaced, T5 is 75s, the altitude is judged at the time T5, if the preset altitude h2 is not reached, the thrust of the main engine is kept unchanged, the current overload is continued to fly, if the preset altitude h2 is reached, the preset time T6 is spaced, T6 is 80s, the thrust of the main engine is increased at the time T6, and the demonstration and verification rocket is made to decelerate and descend; when the height is judged to be smaller than the program preset value h2, the thrust of the main engine is increased, and the rocket body flying overload is kept to be larger than n3 through thrust adjustment; in another embodiment t5 takes the value 80s, and in yet another embodiment t5 takes the value 77.5 s. In another embodiment t6 takes the value 85s, and in yet another embodiment t6 takes the value 82.5 s. In another embodiment n2 is 0.75g and in yet another embodiment n2 is 0.6 g.

And 3, after the moment T6, the demonstration and verification rocket enters a vertical landing final guide section, the flying overload is kept to be larger than n3, n3 is 1.4g, the main engine adjusts the thrust magnitude and the vector direction in a small amplitude mode, the landing speed and the landing attitude of the rocket body are controlled, the landing speed precision and the landing attitude precision meet the design index requirements of a landing system, the rocket body descends in a deceleration mode, the preset time T7 is set at intervals, T7 is 100s, the flying height judgment is carried out at the moment T7, when the flying height is smaller than the program preset value h3, the main engine of the demonstration and verification rocket is closed, the rocket body is recovered in vertical landing, and the vertical take-off and landing demonstration and verification flying are completed. In another embodiment t7 takes the value 120s, and in yet another embodiment t7 takes the value 110 s. In another embodiment n3 is 1.25g and in yet another embodiment n3 is 1.1 g.

The specific maximum height of the rocket in the embodiment is 1000m, wherein the value of h1 is 350-450m, the specific value is 400m, the value of h2 is 250-350m, the specific value is 300m, the value of h3 is 0-1m, and the specific value is 0.5 m. In another possible embodiment, the rocket flying height may be any height greater than 0m, not limited to 1000m, and may be 10000m, or 100000m, 1000000m, and may be larger as required.

The above description is only for the best mode of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.