阅读说明：本技术 可重复使用技术演示验证火箭着陆检测方法、系统及设备 (Reusable technology demonstration verification rocket landing detection method, system and equipment ) 是由 朱佩婕 朴胜志 杨跃 马道远 罗庶 李钧 岳小飞 李金梅 梁家伟 赵学光 胡智珲 于 2021-08-17 设计创作，主要内容包括：为了弥补着陆判别的空白,本发明提供一种可重复使用技术演示验证火箭的着陆检测方法,包括步骤:测量火箭回收支腿缓冲器压力值并判别；测量箭体支腿下端面离地高度值并判别；测量箭体轴向过载并判别；测量火箭回收支腿的辅支腿的冲击值并判别；根据标志在镜头画面中的比例进行判别；当缓冲器压力条件满足时,直接判定为火箭着陆；若缓冲器压力条件不满足,但其他四项条件中有两项同时满足,则判定为火箭着陆；判定火箭着陆后,检测制导关机指令发出状态,若尚未发出发动机关机指令,则由着陆判别结果触发备保关机指令；当地面工作人员通过着陆区前端摄像头观测到火箭已着陆,火箭收到“开始发动机后处理”的遥控指令,即停止上述判别。(In order to make up for the blank of landing judgment, the invention provides a landing detection method for demonstrating and verifying a rocket by using a reusable technology, which comprises the steps of measuring the pressure value of a buffer of a recovery support leg of the rocket and judging; measuring and judging the height value of the lower end surface of the rocket body supporting leg from the ground; measuring and judging the axial overload of the arrow body; measuring and judging the impact value of an auxiliary supporting leg of the rocket recovery supporting leg; judging according to the proportion of the mark in the shot picture; when the pressure condition of the buffer is met, directly judging that the rocket lands; if the pressure condition of the buffer is not met but two of the other four conditions are met simultaneously, judging that the rocket lands; after the rocket is judged to land, detecting a guidance shutdown instruction sending state, and if an engine shutdown instruction is not sent, triggering a backup shutdown instruction according to a landing judgment result; when the ground staff observes that the rocket has landed through the front-end camera of the landing zone, the rocket stops the judgment after receiving a remote control command of starting the engine post-processing.)

1. A landing detection method for a reusable technology demonstration verification rocket is characterized by comprising the following steps:

s1, measuring the pressure value of the rocket recovery leg buffer and judging;

s2, measuring and judging the height value of the lower end surface of the rocket body supporting leg from the ground;

s3, measuring the axial overload of the rocket body and judging;

s4, measuring and judging the impact value of the auxiliary supporting leg of the rocket recovery supporting leg;

s5, installing a camera on the side wall of the arrow body to shoot a large mark drawn on the ground, acquiring the proportion of the mark in a lens picture, comparing the proportion with the proportion of the mark in the lens picture in the landing state of the arrow body obtained by a pre-test, and judging;

s6, when the pressure condition of the buffer is met, directly judging that the rocket lands; if the pressure condition of the buffer is not met, but two conditions of rocket body axial overload, auxiliary supporting leg impact, supporting leg lower end surface ground clearance and camera picture proportion are simultaneously met, judging that the rocket lands, recording the current time as T2, and downloading the rocket by remote measurement;

s7, detecting a guidance shutdown instruction sending state after judging that the rocket is landed, and triggering a backup shutdown instruction according to a landing judgment result if an engine shutdown instruction is not sent;

the determination is stopped when the following event occurs: the ground staff observes that the rocket has landed through a front-end camera of a landing zone, and the rocket receives a remote control command of starting engine post-processing;

wherein step S1-5 is performed in parallel.

2. The landing detection method of a reusable technology demonstration validation rocket according to claim 1, wherein the step S1 specifically comprises:

measuring the pressure Pmd1-4 in a nitrogen chamber or an oil cylinder of four buffers of the recovery supporting leg, wherein the sampling period is 50-1000 Hz; when the height of the lower end surface of the arrow body supporting leg from the ground is less than 5m, the four counters Cmd1-4 start to count, the initial values of the Cmd1-4 are all 0, when the pressure measurement value is greater than the binding threshold value Pth, the corresponding counter is increased by one, and when the pressure measurement value is less than or equal to the binding threshold value Pth, the counter is cleared by 0; when three terms in Cmd1-4 are greater than Kmd at the same time, the buffer pressure condition is judged to be met, and the Kmd is generally 20-35.

3. The landing detection method of a repeatable technology demonstration validation rocket according to claim 1, wherein the step S2 is specifically:

the actual ground clearance Hgd1-2 of the lower end surface of the arrow body supporting leg is respectively measured by two height meters,wherein H_tx,kThe ground clearance of the antenna installation position of the altimeter in the kth calculation period is the axial distance between the antenna installation position of the altimeter and the lower end face of the supporting leg, n is generally 10-20, and the sampling period is 10-100 Hz; when the height of the lower end face of the arrow body supporting leg from the ground is less than 5m, two counters Cgd1-2 start to count, the initial values of Cgd1-2 are both 0, when Hgd1 or Hgd2 is less than the binding threshold Hth, the corresponding counter is increased by one, and when Hgd1 or Hgd2 is less than or equal to the binding threshold Hth, the corresponding counter is cleared by 0; when one value of Cgd1-2 is larger than Kgd, the ground clearance condition of the lower end face of the supporting leg is judged to be met, and the value of Kgd is generally 15-25.

4. The landing detection method of a reusable technology demonstration validation rocket according to claim 1, wherein the step S3 specifically comprises:

measuring axial overload of an arrow body, namely, the arrow body overload Nx1 in the x direction under an arrow body coordinate system, wherein the sampling period is 50-100Hz, and because the large overload generated by the arrow body landing has short duration and violent change, the arrow body overload does not carry out the smoothing treatment of a plurality of sampling values; when the height of the lower end surface of the arrow body supporting leg from the ground is less than 5m, the counter Cnx starts counting, the initial value Cnx is 0, when the overload measured value is greater than the binding threshold value Nth, the counter Cnx is increased by one, and when the overload measured value is less than or equal to the binding threshold value Nth, the counter is cleared by 0; when the Cnx value is larger than Knx, the rocket body is judged to meet the rocket body axial overload condition, and the Knx value is generally 2-3.

5. The landing detection method of a reusable technology demonstration validation rocket according to claim 1, wherein the step S4 specifically comprises:

when the ground clearance of the lower end surface of the rocket body supporting leg is less than 5m, the rocket-borne computer sends a command of starting recording impact to the measuring system, the sampling period is 10-20kHz, and the four counters Ccj1-4 start counting; measuring the impact of four auxiliary legs of a recovery legWherein I_zt,kFor the impact of the auxiliary leg in the kth sampling period, n is generally 100-; the initial values of Ccj1-4 are all 0, when the impact value Izt is greater than the binding threshold value Ith, the corresponding counter is increased by one, and when the pressure measurement value is less than or equal to the binding threshold value Ith, the counter is cleared by 0; when three values of Ccj1-4 are greater than Kcj, the impact condition of the auxiliary support leg is determined to be satisfied, and the value of Kcj is generally 150-200.

6. The landing detection method of a reusable technology demonstration validation rocket according to claim 1, wherein the step S5 specifically comprises:

the method comprises the steps of drawing a large mark on the ground of a landing area, shooting the mark by using a camera installed on the side wall of an arrow body, comparing the proportion Cbz of the mark in a lens picture with the proportion Cbl of the mark in the lens picture in the arrow body landing state obtained by a pre-test, and judging that the camera picture proportion condition is met when more than Kbz frames of video pictures meet | Cbz-Cbz | < Bth within 2 seconds, wherein Kbz generally takes a value of 5-10.

7. A landing detection system for demonstrating and verifying a rocket by using a reusable technology is characterized by comprising a landing data processing module and a landing judging processing module;

the landing data processing module is used for acquiring and recording pressure sensor measurement data, rocket body axial overload data obtained by inertial measurement, impact values of four auxiliary supporting legs of a recovery supporting leg, supporting leg ground clearance data obtained by altimeter measurement and camera picture proportion;

and the landing judgment processing module is used for judging landing according to the acquired five judgment condition data and recording the landing time.

8. The landing detection system of a reusable technology demonstration validation rocket as recited in claim 7, wherein the landing decision processing module performs the landing decision according to the following steps:

a. measuring the pressure Pmd1-4 in a nitrogen chamber or an oil cylinder of four buffers of the recovery supporting leg, wherein the sampling period is 1 kHz; when the height of the lower end surface of the arrow body supporting leg from the ground is less than 5m, the four counters Cmd1-4 start to count, the initial values of the Cmd1-4 are all 0, when the pressure measurement value is greater than the binding threshold value Pth, the corresponding counter is increased by one, and when the pressure measurement value is less than or equal to the binding threshold value Pth, the counter is cleared by 0; when three terms in Cmd1-4 are larger than Kmd at the same time, judging that the buffer pressure condition is met, wherein the Kmd is generally 20-35;

b. the actual ground clearance Hgd1-2 of the lower end surface of the arrow body supporting leg is respectively measured by two height meters,wherein H_tx,kThe ground clearance of the antenna installation position of the altimeter in the kth calculation period is the axial distance between the antenna installation position of the altimeter and the lower end face of the supporting leg, n is generally 10-20, and the sampling period is 100 Hz; when the height of the lower end surface of the arrow body leg from the ground is less than 5m, two counters Cgd1-2 start to countInitial values of Cgd1-2 are both 0, when Hgd1 or Hgd2 is smaller than the binding threshold Hth, the corresponding counter is increased by one, and when Hgd1 or Hgd2 is smaller than or equal to the binding threshold Hth, the corresponding counter is cleared by 0; when one Cgd1-2 value is larger than Kgd, judging that the ground clearance condition of the lower end face of the supporting leg is met, wherein Kgd generally takes a value of 15-25;

c. measuring axial overload of an arrow body, namely the arrow body overload Nx1 in the x direction under an arrow body coordinate system, wherein the sampling period is 100Hz, and because the large overload generated by the arrow body landing has short duration and violent change, the arrow body overload does not carry out the smoothing treatment of a plurality of sampling values; when the height of the lower end surface of the arrow body supporting leg from the ground is less than 5m, the counter Cnx starts counting, the initial value Cnx is 0, when the overload measured value is greater than the binding threshold value Nth, the counter Cnx is increased by one, and when the overload measured value is less than or equal to the binding threshold value Nth, the counter is cleared by 0; when the Cnx value is larger than Knx, the rocket body is judged to meet the rocket body axial overload condition, and the Knx value is generally 2-3;

d. when the ground clearance of the lower end surface of the rocket body supporting leg is less than 5m, the rocket-borne computer sends a command of starting recording impact to the measuring system, the sampling period is 20kHz, and the four counters Ccj1-4 start counting; measuring the impact of four auxiliary legs of a recovery legWherein I_zt,kFor the impact of the auxiliary leg in the kth sampling period, n is generally 100-; the initial values of Ccj1-4 are all 0, when the impact value Izt is greater than the binding threshold value Ith, the corresponding counter is increased by one, and when the pressure measurement value is less than or equal to the binding threshold value Ith, the counter is cleared by 0; when three values of Ccj1-4 are more than Kcj, judging that the auxiliary support leg impact condition is met, and generally taking the Kcj value as 150-20;

e. drawing a large mark on the ground of a landing zone, shooting the mark by using a camera arranged on the side wall of an arrow body, comparing the proportion Cbz of the mark in a lens picture with the proportion Cbl of the mark in the lens picture in the arrow body landing state obtained by a pre-test, and judging that the proportion condition of the camera picture is met if more than Kbz frames of video pictures meet | Cbz-Cbz | < Bth within 2 seconds, wherein Kbz generally takes a value of 5-10;

f. when the pressure condition of the buffer is met, directly judging that the rocket lands; if the pressure condition of the buffer is not met, but two conditions of rocket body axial overload, ground clearance of the lower end face of the supporting leg, auxiliary supporting leg impact and camera picture proportion are simultaneously met, judging that the rocket is grounded and landed, recording the current moment as T2, and downloading the rocket through remote measurement;

g. detecting a guidance shutdown instruction sending state after judging that the rocket is landed, and triggering a backup shutdown instruction according to a landing judgment result if an engine shutdown instruction is not sent;

the determination is stopped when the following event occurs: ground staff observe that the rocket has landed through a front-end camera of a landing zone, and the rocket receives a remote control command of starting engine post-processing.

9. The landing detection system of a reusable technology demonstration validation rocket of claim 7 further comprising a rocket landing detection execution module;

the rocket landing detection execution module is used for judging and executing the control command according to a preset landing state, and executing the landing data processing module and the landing judging processing module.

10. An apparatus for performing a landing detection method for a reusable technical demonstration validation rocket, comprising:

the storage is used for storing a computer program and a rocket landing state judging method;

a processor for executing the computer program and the rocket landing state judging method to realize the steps of the reusable technology demonstration and verification rocket landing detection method according to any one of claims 1 to 6.

Technical Field

The invention relates to the technical field of aerospace, and mainly provides a landing detection method, a landing detection system and landing detection equipment for a reusable technology demonstration verification rocket.

Background

The reusable technology demonstration and verification rocket generally adopts a liquid rocket engine, is low in flying height and not in orbit, and is provided with an altimeter for measuring the height of the rocket body above the ground and a recovery supporting leg for buffering landing impact and overload. The difference with the traditional rocket is that the rocket has a complex post-processing flow after landing, and the flow has strict time sequence requirements and directly influences whether the rocket can be reused. The rocket landing time is used as the reference starting time of the post-processing flow time sequence, the detection of the rocket landing time has important significance, and no landing judgment method is referred at present. Meanwhile, the demonstration verifies that a rocket is limited by the uncertainty of the performance of the engine and the height measurement precision, a guidance shutdown instruction can not be generated in time, the uncertain influence is brought to the rocket body after landing, and the landing shutdown can be used as a mode of backup shutdown.

Disclosure of Invention

In order to make up for the blank of landing judgment, the invention provides a landing detection method for a reusable technology demonstration verification rocket, wherein a buffer is arranged on a recovery supporting leg of the rocket, and the pressure value born by the buffer can be measured, and the method comprises the following steps:

s1, measuring the pressure value of the rocket recovery leg buffer and judging;

s2, measuring and judging the height value of the lower end surface of the rocket body supporting leg from the ground;

s3, measuring the axial overload of the rocket body and judging;

s4, measuring and judging the impact value of the auxiliary supporting leg of the rocket recovery supporting leg;

s5, installing a camera on the side wall of the arrow body to shoot a large mark drawn on the ground, acquiring the proportion of the mark in a lens picture, comparing the proportion with the proportion of the mark in the lens picture in the landing state of the arrow body obtained by a pre-test, and judging;

s6, when the pressure condition of the buffer is met, directly judging that the rocket lands; if the pressure condition of the buffer is not met, but two conditions of rocket body axial overload, auxiliary supporting leg impact, supporting leg lower end surface ground clearance and camera picture proportion are simultaneously met, judging that the rocket lands, recording the current time as T2, and downloading the rocket by remote measurement; the method is mainly characterized in that the speed, overload and attitude information of starting arrow landing can directly influence the overload and impact of arrow landing, the information changes due to inconsistent flight states, the overload and impact judgment can be invalid, but the landing process inevitably causes the compression of supporting legs, so the pressure condition of a buffer is the direct condition of landing judgment, and the overload, impact and ground clearance are required to be combined and judged;

s7, detecting a guidance shutdown instruction sending state after judging that the rocket is landed, and triggering a backup shutdown instruction according to a landing judgment result if an engine shutdown instruction is not sent;

the determination is stopped when the following event occurs: the ground staff observes that the rocket has landed through a front-end camera of a landing zone, and the rocket receives a remote control command of starting engine post-processing;

wherein step S1-5 is performed in parallel.

Further, the step S1 is specifically: measuring the pressure Pmd1-4 in a nitrogen chamber or an oil cylinder of four buffers of the recovery supporting leg, wherein the sampling period is 50-1000Hz, and the specific value is related to the concerned pressure frequency band range; when the height of the lower end surface of the arrow body supporting leg from the ground is less than 5m, the four counters Cmd1-4 start to count, the initial values of the Cmd1-4 are all 0, when the pressure measurement value is greater than the binding threshold value Pth, the corresponding counter is increased by one, and when the pressure measurement value is less than or equal to the binding threshold value Pth, the counter is cleared by 0; when three terms in Cmd1-4 are greater than Kmd at the same time, the buffer pressure condition is judged to be met, and the Kmd is generally 20-35.

Further, the step S2 is specifically: : the actual ground clearance Hgd1-2 of the lower end surface of the arrow body supporting leg is respectively measured by two height meters,wherein H_tx,kThe ground clearance of the antenna installation position of the altimeter in the kth calculation period is the axial distance between the antenna installation position of the altimeter and the lower end face of the supporting leg, the sampling period is 10-100Hz, and since the requirement on the measurement accuracy of the landing time is low, the judgment accuracy is guaranteed, n is generally 10-20, the data volume to be processed is increased, and the judgment time is prolonged; when the height of the lower end face of the arrow body supporting leg from the ground is less than 5m, two counters Cgd1-2 start to count, the initial values of Cgd1-2 are both 0, when Hgd1 or Hgd2 is less than the binding threshold Hth, the corresponding counter is increased by one, and when Hgd1 or Hgd2 is less than or equal to the binding threshold Hth, the corresponding counter is cleared by 0; when one value of Cgd1-2 is larger than Kgd, the ground clearance condition of the lower end face of the supporting leg is judged to be met, and the value of Kgd is generally 15-25.

Further, the step S3 is specifically: measuring axial overload of an arrow body, namely, the arrow body overload Nx1 in the x direction under an arrow body coordinate system, wherein the sampling period is 50-100Hz, and because the large overload generated by the arrow body landing has short duration and violent change, the arrow body overload does not carry out the smoothing treatment of a plurality of sampling values; when the height of the lower end surface of the arrow body supporting leg from the ground is less than 5m, the counter Cnx starts counting, the initial value Cnx is 0, when the overload measured value is greater than the binding threshold value Nth, the counter Cnx is increased by one, and when the overload measured value is less than or equal to the binding threshold value Nth, the counter is cleared by 0; when the Cnx value is larger than Knx, the rocket body is judged to meet the rocket body axial overload condition, and the Knx value is generally 2-3.

Further, the step S4 is specifically: due to the fact that the data volume of the impact record is large, when the ground clearance of the lower end face of the rocket body supporting leg is smaller than 5m, the rocket-borne computer sends an instruction of 'starting to record the impact' to the measuring system, the sampling period is 10-20kHz, and the four counters Ccj1-4 start to count; measuring the impact of four auxiliary legs of a recovery legWherein I_zt,kFor the impact of the auxiliary leg in the kth sampling period, n is generally 100-; the initial values of Ccj1-4 are all 0, when the impact value Izt is greater than the binding threshold value Ith, the corresponding counter is increased by one, and when the pressure measurement value is less than or equal to the binding threshold value Ith, the counter is cleared by 0; when three values of Ccj1-4 are greater than Kcj, the impact condition of the auxiliary support leg is determined to be satisfied, and the value of Kcj is generally 150-200.

Further, the step S5 is specifically: the method comprises the steps of drawing a large mark on the ground of a landing area, shooting the mark by using a camera installed on the side wall of an arrow body, comparing the proportion Cbz of the mark in a lens picture with the proportion Cbl of the mark in the lens picture in the arrow body landing state obtained by a pre-test, and judging that the camera picture proportion condition is met when more than Kbz frames of video pictures meet | Cbz-Cbz | < Bth within 2 seconds, wherein Kbz generally takes a value of 5-10.

The invention also provides a landing detection system for demonstrating and verifying the rocket by using the reusable technology, which is characterized by comprising a landing data processing module and a landing judging and processing module;

the landing data processing module is used for acquiring and recording pressure sensor measurement data, rocket body axial overload data obtained by inertial measurement, impact values of four auxiliary supporting legs of a recovery supporting leg, supporting leg ground clearance data obtained by altimeter measurement and camera picture proportion;

and the landing judgment processing module is used for judging landing according to the acquired five judgment condition data and recording the landing time.

Furthermore, the landing judgment processing module judges the landing according to the following steps,

a. measuring the pressure Pmd1-4 in a nitrogen chamber or an oil cylinder of four buffers of the recovery supporting leg, wherein the sampling period is 50-1000 Hz; when the height of the lower end surface of the arrow body supporting leg from the ground is less than 5m, the four counters Cmd1-4 start to count, the initial values of the Cmd1-4 are all 0, when the pressure measurement value is greater than the binding threshold value Pth, the corresponding counter is increased by one, and when the pressure measurement value is less than or equal to the binding threshold value Pth, the counter is cleared by 0; when three terms in Cmd1-4 are greater than Kmd at the same time, the buffer pressure condition is judged to be met, and the Kmd is generally 20-35.

b. The actual ground clearance Hgd1-2 of the lower end surface of the arrow body supporting leg is respectively measured by two height meters,wherein H_tx,kThe ground clearance of the antenna installation position of the altimeter in the kth calculation period is the axial distance between the antenna installation position of the altimeter and the lower end face of the supporting leg, n is generally 10-20, and the sampling period is 10-100 Hz; when the height of the lower end face of the arrow body supporting leg from the ground is less than 5m, two counters Cgd1-2 start to count, the initial values of Cgd1-2 are both 0, when Hgd1 or Hgd2 is less than the binding threshold Hth, the corresponding counter is increased by one, and when Hgd1 or Hgd2 is less than or equal to the binding threshold Hth, the corresponding counter is cleared by 0; when one value of Cgd1-2 is larger than Kgd, the ground clearance condition of the lower end face of the supporting leg is judged to be met, and the value of Kgd is generally 15-25.

c. The axial overload of the arrow body is measured, namely the arrow body overload Nx1 in the x direction under an arrow body coordinate system is measured, the sampling period is 50-100Hz, and because the large overload generated by the arrow body landing has short duration and violent change, the smoothing processing of a plurality of sampling values is not performed. When the height of the lower end surface of the arrow body leg from the ground is less than 5m, the counter Cnx starts counting, the initial value Cnx is 0, when the overload measured value is greater than the binding threshold value Nth, the counter Cnx is increased by one, and when the overload measured value is less than or equal to the binding threshold value Nth, the counter is cleared by 0. When the Cnx value is larger than Knx, the rocket body is judged to meet the rocket body axial overload condition, and the Knx value is generally 2-3.

d. When the ground clearance of the lower end surface of the rocket body supporting leg is less than 5m, the rocket-borne computer sends a command of starting recording impact to the measuring system, the sampling period is 10-20kHz, and the four counters Ccj1-4 start counting; measuring the impact of four auxiliary legs of a recovery legWherein I_zt,kFor the impact of the auxiliary leg in the kth sampling period, n is generally 100-; the initial values of Ccj1-4 are all 0, when the impact value Izt is greater than the binding threshold value Ith, the corresponding counter is increased by one, and when the pressure measurement value is less than or equal to the binding threshold value Ith, the counter is cleared by 0; when three values of Ccj1-4 are greater than Kcj, the impact condition of the auxiliary support leg is determined to be satisfied, and the value of Kcj is generally 150-200.

e. Drawing a large mark on the ground of a landing zone, shooting the mark by using a camera arranged on the side wall of an arrow body, comparing the proportion Cbz of the mark in a lens picture with the proportion Cbl of the mark in the lens picture in the arrow body landing state obtained by a pre-test, and judging that the proportion condition of the camera picture is met if more than Kbz frames of video pictures meet | Cbz-Cbz | < Bth within 2 seconds, wherein Kbz generally takes a value of 5-10;

f. when the pressure condition of the buffer is met, directly judging that the rocket lands; if the pressure condition of the buffer is not met, but two conditions of rocket body axial overload, ground clearance of the lower end face of the supporting leg, auxiliary supporting leg impact and camera picture proportion are simultaneously met, judging that the rocket is grounded and landed, recording the current moment as T2, and downloading the rocket through remote measurement;

g. and after judging that the rocket lands, detecting a guidance shutdown instruction sending state, and if an engine shutdown instruction is not sent, triggering a standby shutdown instruction according to a landing judgment result.

The determination is stopped when the following event occurs: ground staff observe that the rocket has landed through a front-end camera of a landing zone, and the rocket receives a remote control command of starting engine post-processing.

Further, the landing detection system for demonstrating and verifying the rocket by the reusable technology also comprises a rocket landing detection execution module;

the rocket landing detection execution module is used for judging and executing the control command according to a preset landing state, and executing the landing data processing module and the landing judging processing module.

The invention also provides a device for executing the landing detection method of the reusable technology demonstration verification rocket, which comprises the following steps:

the storage is used for storing a computer program and a rocket landing state judging method;

and the processor is used for executing the computer program and the rocket landing state judging method so as to realize the steps of the landing detection method for demonstrating and verifying the rocket by the reusable technology.

Compared with the prior art, the invention has the following beneficial effects:

the blank of the rocket landing judging method is supplemented, and the rocket landing time can be strictly detected and judged and used as the reference time of the post-processing flow time sequence after the rocket is landed. Meanwhile, the rocket is demonstrated and verified to be limited by the uncertainty of the performance of the engine and the height measurement precision, a guidance shutdown instruction can not be generated in time, and uncertain influences are brought to a rocket body after landing.

Compared with the situation that misjudgment risks exist when data acquired by a single criterion have deviation, the method judges whether the rocket lands according to five judgment conditions, considers the conditions of sensor fault redundancy and rocket body attitude inclination, comprehensively considers all judgment conditions, and obtains a more accurate and reliable judgment conclusion.

Drawings

FIG. 1 is a flow chart of a method for determining a buffer pressure condition;

FIG. 2 is a flow chart of a method for judging a ground clearance condition;

FIG. 3 is a flow chart of a method for judging an arrow body axial overload condition;

FIG. 4 is a flow chart of an auxiliary leg impact condition determination method;

FIG. 5 is a flow chart of a rocket landing determination method; in the figure, rocket landing is realized when the rocket touches down;

fig. 6 is an arrow coordinate system.

Detailed Description

The present invention will be described in further detail below with reference to specific embodiments in order to make the present invention better understood by those skilled in the art.

In this embodiment, a landing detection method for a reusable technology demonstration verification rocket is provided, where a buffer is provided in a recovery leg of the rocket, and a pressure value borne by the buffer can be measured, and the method includes:

s1, measuring the pressure Pmd1-4 in a nitrogen chamber or an oil cylinder of four buffers of the recovery supporting leg, wherein the sampling period is 50-1000 Hz; when the height of the lower end surface of the arrow body supporting leg from the ground is less than 5m, the four counters Cmd1-4 start to count, the initial values of the Cmd1-4 are all 0, when the pressure measurement value is greater than the binding threshold value Pth, the corresponding counter is increased by one, and when the pressure measurement value is less than or equal to the binding threshold value Pth, the counter is cleared by 0; when three terms in Cmd1-4 are larger than Kmd at the same time, judging that the buffer pressure condition is met, wherein the Kmd is generally 20-35; buffer pressure threshold: the mass of the rocket body during landing and the design parameters of the buffer are related, and the mass is determined through ground tests and mathematical simulation. Fig. 1 is a flow chart of a method for determining the pressure condition of the buffer.

S2, the actual ground clearance Hgd1-2 of the lower end surface of the arrow body supporting leg is respectively measured by two height meters,wherein H_tx,kThe ground clearance of the antenna installation position of the altimeter in the kth calculation period is the axial distance between the antenna installation position of the altimeter and the lower end face of the supporting leg, n is generally 10-20, and the sampling period is 10-100 Hz; when the height of the lower end surface of the arrow body leg from the ground is less than 5m, two counters Cgd1-2 start to count, the initial value of Cgd1-2 is 0, when Hgd1 or Hgd2 is less than the binding threshold Hth, the corresponding counter is increased by one, and when Hgd1 or Hgd2 is less than or equal to the binding threshold HthWhen a threshold Hth is set, the corresponding counter is cleared by 0; when one Cgd1-2 value is larger than Kgd, judging that the ground clearance condition of the lower end face of the supporting leg is met, wherein Kgd generally takes a value of 15-25; arrow body ground clearance threshold: the absolute value of the altimeter is smaller than the absolute value of the altimeter measurement accuracy. Fig. 2 is a flowchart of a method for determining the height above the ground.

S3, axial overload of the arrow body is measured, namely the arrow body overload Nx1 in the x direction under the arrow body coordinate system shown in fig. 6 is measured, the sampling period is 50-100Hz, and because the large overload generated by the arrow body landing has short duration and violent change, the smoothing processing of multiple sampling values is not performed. When the height of the lower end surface of the arrow body leg from the ground is less than 5m, the counter Cnx starts counting, the initial value Cnx is 0, when the overload measured value is greater than the binding threshold value Nth, the counter Cnx is increased by one, and when the overload measured value is less than or equal to the binding threshold value Nth, the counter is cleared by 0. When the Cnx value is larger than Knx, the rocket body is judged to meet the rocket body axial overload condition, and the Knx value is generally 2-3; axial overload threshold: the initial speed, the attitude and the arrow structure of the arrow landing process are related, and are determined through ground tests and mathematical simulation. Fig. 3 is a flowchart of the method for determining the axial overload condition of the rocket body.

S4, when the ground clearance of the lower end face of the rocket body supporting leg is less than 5m, the rocket-borne computer sends a command of starting recording impact to the measuring system, the sampling period is 10-20kHz, and the four counters Ccj1-4 start counting; measuring the impact of four auxiliary legs of a recovery legWherein I_zt,kFor the auxiliary leg impact of the kth sampling period, n is typically 100-. The initial values of Ccj1-4 are all 0, when the impact value Izt is greater than the binding threshold value Ith, the corresponding counter is increased by one, and when the pressure measurement value is less than or equal to the binding threshold value Ith, the counter is cleared by 0; when three values of Ccj1-4 are more than Kcj, the auxiliary leg impact condition is judged to be met, and the Kcj value is generally 150-200; impact threshold: the initial speed and the attitude of the rocket body during landing are related, and are determined through ground tests and mathematical simulation. FIG. 4 is a flowchart of an auxiliary leg impact condition determination method。

S5, drawing a large mark on the ground of a landing zone, shooting the mark by using a camera arranged on the side wall of an arrow body, comparing the proportion Cbz of the mark in a lens picture with the proportion Cbl of the mark in the lens picture under the arrow body landing state obtained by a pre-test, and judging that the proportion condition of the camera picture is met when more than Kbz frames of video pictures meet | Cbz-Cbz | < Bth within 2 seconds, wherein Kbz generally takes a value of 5-10; picture threshold value Bth: the attitude of the rocket during landing and the ground clearance of the camera are related, and the attitude is determined through ground tests.

S6, when the pressure condition of the buffer is met, directly judging that the rocket lands; and if the pressure condition of the buffer is not met, but two conditions of rocket body axial overload, auxiliary supporting leg impact, supporting leg lower end surface ground clearance and camera picture proportion are simultaneously met, judging that the rocket lands, recording the current time as T2, and downloading the rocket by remote measurement. Fig. 5 is a flowchart of a rocket landing determination method.

Specifically, the judgment is carried out according to the pressure value measured by the buffer pressure sensor: in the rocket landing process, a landing leg foot pad is in contact with the ground of a landing zone, and a nitrogen chamber and an oil cylinder in a buffer begin to be rapidly compressed under the action of impact force, so that the pressure is increased to a threshold value in a short period, wherein the threshold value is greater than the pressure value at any moment in a flight state; after the arrow body becomes stable, the amount of compression decreases and stabilizes at a value, and the pressure also decreases rapidly.

Because the impact acquisition frequency is high, the data volume accounts for a large proportion of the bus transmission, and the transmission of other sensor data is easily interfered, when the rocket-borne computer judges that the ground clearance of the lower end surface of the rocket supporting leg is less than 5m, an instruction of 'starting to record impact' is sent to the measuring system, and the time for sending the instruction is recorded.

Considering that when the height of the arrow body from the ground is small, the temperature of the lower part of the supporting leg is too high through ground reflection by the tail flame of the engine, and the operation of nearby electrical equipment is not facilitated, the buffer is arranged on the main supporting leg, impact measurement data of a high-frequency part are filtered, and therefore the impact sensor is arranged at the connecting point of the auxiliary supporting leg and the tail section, and high-frequency impact caused by landing can be effectively measured.

Specifically, judging according to arrow overload: at the moment of arrow landing, due to the influences of initial speed, overload and attitude, the supporting legs generate impact force, the buffer can greatly attenuate impact acceleration, but the influence on low-frequency overload acceleration is small, so that whether the arrow lands or not can be judged through overload change in the sensitive touchdown process of the inertial group arranged in the cabin section.

During the rocket returns, the measured altitude descends until the rocket body lands, and the measured altitude value is stabilized near a constant value (the distance from the altimeter antenna to the foot pad).

The impact acceleration generated by the landing impact force can be measured by an impact sensor arranged on the auxiliary supporting leg, and can be used for judging whether the rocket body lands or not.

The starting time for judging whether the arrow body starts to land or not according to the pressure, the overload, the height measurement value and the picture scale is as follows: the arrow body measures less than 5m from the ground.

Impact and overload value changes are generated during landing, and then the buffer has pressure changes; the altitude remains almost unchanged after landing.

Specifically, the criterion of this embodiment is as follows:

cmd1-4 represents the number of times the measured value of the buffer pressure corresponding to the index is continuously less than the binding threshold Pth, Kmd is the binding value representing the number of times the buffer pressure condition is met, and Kmd is typically 20-35, such as 20, 22, 25, 28, 30, 32, 35, etc. The specific numerical values are obtained through simulation or experiment and are related to the design values of the buffer, the rocket body landing speed and the rocket body landing attitude.

When more than three items in Cmd1-4 are less than Kmd, judging that the buffer pressure condition is met; due to the deviation of the machining process and the fact that the arrow body has a certain inclination angle in the landing process, various different support leg grounding modes exist in the landing process, and the condition of fault redundancy of the pressure sensor is considered, so that the criterion is set to be 4 and 3.

Ccj1-4 indicates the number of times that the measured value of the impact of the auxiliary leg corresponding to the label is continuously greater than the binding threshold Ith, Kcj is the binding value indicating the number of times that the impact condition of the auxiliary leg is satisfied, Kcj is generally 150-200, such as 150, 160, 170, 180, 190, 200, etc. The specific numerical values are obtained through simulation or experiment and are related to the design values of the buffer, the rocket body landing speed and the rocket body landing attitude.

Representing the average value of the impact measurements in the last continuous n periods; wherein I_zt,kFor the sub-leg impact of the kth sampling period, n is generally 100-.

When more than three Ccj1-4 values are more than Kcj, judging that the buffer pressure condition is met; due to the deviation of the machining process and the fact that the arrow body has a certain inclination angle in the landing process, various different support leg grounding modes exist in the landing process, and the condition of fault redundancy of the pressure sensor is considered, so that the criterion is set to be 4 and 3.

Cnx, the number of times that the measured value of the arrow body overload is continuously greater than the binding threshold value Nth, Knx is the binding value, the number of times that the arrow body axial overload condition is met is shown, and Knx generally takes a value of 2-3.

Cgd1-2 represents the number of times that the actual height of the lower end face of the arrow body leg from the ground measured by the height gauge is continuously less than the binding threshold value Hth, Kgd is the binding value representing the number of times that the condition of the height of the lower end face of the leg from the ground is satisfied, and Kgd generally takes the value of 15-25, for example, 15, 17, 19, 20, 22, 25, etc.

When one value of Cgd1-2 is larger than Kgd, the condition that the ground clearance height of the lower end face of the leg is satisfied is judged.

Represents the average of the height measurements over the last n consecutive periods, where H_tx,kThe height of the mounting position of the altimeter antenna in the kth calculation period from the ground and the axial distance of the mounting position of the altimeter antenna from the lower end face of the supporting leg are generally 10-20, such as 10, 13, 15, 17, 20 and the like.

Kbz represents the number of frames within 2 seconds that the deviation of the proportion of the area mark occupying the frame and the proportion of the frame corresponding to the landing state is less than the binding threshold Bth, Kbz generally takes a value of 5-10, such as 5, 7, 8, 9, 10, etc.;

specifically, the combined landing determination method of the embodiment includes:

whether the rocket lands or not can not be accurately judged by judging the condition alone;

the initial landing state (speed, attitude) will directly affect the overload and impact measurement values after landing, but the threshold value is a fixed value, such as: when the initial speed is low, the maximum values of overload and impact are small, and the judgment is possible to fail;

the altimeter has measurement errors, so the landing judgment needs to be completed together with other criteria.

The proportion of the marks shot by the cameras on the arrow to the picture is greatly influenced by the landing posture of the arrow body, and the judgment is possibly invalid;

due to the influence of gravity, the buffer can be compressed to generate pressure in the landing process, and the difference from the flying state is large, so that the judgment is easy; therefore, the pressure of the buffer is used as a main judgment mode for landing, and overload, impact, ground clearance and picture scale are used as auxiliary judgment modes.

Judging the order of firstly judging impact, secondly judging pressure and overload, and finally judging height and picture proportion; actually, the five measurement values are collected at the same time, but theoretically, in the rocket landing process, a foot pad of the supporting leg is contacted with the ground of a landing area, and the supporting leg generates impact force firstly due to the influence of initial speed, overload and attitude; and then a nitrogen chamber and an oil cylinder in the buffer begin to compress, so that the pressure is increased, and the impact force is transmitted to the inertial unit installation position through the buffer and the cabin section.

S7, when the rocket is judged to be required to do work after landing: downloading the landing time by telemetry; and after judging that the rocket lands, detecting a guidance shutdown instruction sending state, and if an engine shutdown instruction is not sent, triggering a standby shutdown instruction according to a landing judgment result.

The determination is stopped when the following event occurs: ground staff observe that the rocket has landed through a front-end camera of a landing zone, and the rocket receives a remote control command of starting engine post-processing.

Based on the same invention concept, the invention provides a platform separation detection system for demonstrating and verifying a rocket by using a reusable technology, which comprises a landing data processing module and a platform separation judging and processing module;

the landing data processing module is used for acquiring and recording pressure sensor measurement data, rocket body axial overload data obtained by inertial measurement, impact values of four auxiliary supporting legs of a recovery supporting leg, supporting leg ground clearance data obtained by altimeter measurement and camera picture proportion;

and the landing judgment processing module is used for judging landing according to the acquired five judgment condition data and recording the landing time.

In particular, the module design code or instructions may be software and/or firmware executed by processing circuitry including one or more processors, such as one or more Digital Signal Processors (DSPs), general purpose microprocessors, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Thus, the term "processor," as used herein, may refer to any of the foregoing structure or any other structure more suitable for implementing the techniques described herein. In addition, in some aspects, the functionality described in this disclosure may be provided in software modules and hardware modules.

If implemented in hardware, the invention relates to an apparatus, which may be, for example, a processor or an integrated circuit device, such as an integrated circuit chip or chipset. Alternatively or additionally, if implemented in software or firmware, the techniques may implement a data storage medium readable at least in part by a computer, comprising instructions that when executed cause a processor to perform one or more of the above-described methods. For example, a computer-readable data storage medium may store instructions that are executed, such as by a processor.

The method and arrangement of the invention may be implemented in many ways on the basis of the same inventive concept. For example, the methods and apparatus of the present invention may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order for the steps of the method is for illustrative purposes only, and the steps of the method of the present invention are not limited to the order specifically described above unless specifically indicated otherwise. Furthermore, in some embodiments, the present invention may also be embodied as a program recorded in a recording medium, the program including machine-readable instructions for implementing a method according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.