CN210220849U

CN210220849U - Liquid rocket

Info

Publication number: CN210220849U
Application number: CN201920777619.1U
Authority: CN
Inventors: Ruikang Yang; 杨瑞康; Zhichao Xuan; 宣智超; Yuguo Hou; 侯雨果; Zheng Dai; 戴政
Original assignee: Landspace Technology Co Ltd
Current assignee: Landspace Technology Co Ltd
Priority date: 2019-05-28
Filing date: 2019-05-28
Publication date: 2020-03-31
Anticipated expiration: 2029-05-28

Abstract

The utility model discloses a liquid rocket contains a rocket sublevel, and a rocket sublevel contains power tail cabin section, locates with drawing in the parachute package of power tail cabin section and general power tail cabin section with the explosion separation structure that a rocket sublevel is connected. Wherein the detonation separating surface is located between the bottom of the tank of the rocket primary sub-stage and the power tail section; after the rocket is separated in one sub-stage, the explosion separation structure is detonated, so that the power tail cabin section is separated from the bottom of the storage tank along the explosion separation surface, and the parachute pack is opened to reduce the descending speed of the power tail cabin section. Compared with the prior art, the structure has the advantages of convenient control, safety, reliability, cost saving, capability of overhauling, testing and cleaning the power tail cabin section, and repeated application.

Description

Liquid rocket

Technical Field

The utility model relates to a liquid rocket engine field, in particular to liquid rocket.

Background

With the rapid development of the aerospace industry, various technologies related to rockets also realize the rapid advance. Currently, the continuous reduction of rocket manufacturing and launch costs as the only vehicle currently launching satellites into space is a pursuit goal of large commercial space companies.

Taking rocket recovery as an example, the liquid rocket recovery method which is the mainstream at present mainly takes a reverse landing mode represented by spacex company and blue origin company in the United states. The landing support legs are additionally arranged on the rocket body, the engine at the bottom of the rocket body ignites for the second time when the rocket body is close to the ground, the thrust of the engine is changed, and the position of the rocket is adjusted to realize landing and fixed-point landing, so that the recovery of a first sub-stage of the whole rocket is completed, and the rocket can be reused after being cleaned, maintained and tested. However, the method needs the engine to have the capability of multiple ignition and the capability of adjusting the thrust in a large range, the technical difficulty is high, and meanwhile, the reliability of the recovery method is reduced due to the added systems. For example, spacex corporation has experienced a recovery failure due to an engine not starting properly. In addition, the method needs to be additionally provided with a large-scale supporting leg to ensure the stability during landing. The one-level slenderness ratio of the whole rocket body is large, the weight is large, the gravity center is high, and the situation that the whole rocket body cannot be stabilized by the supporting legs for many times to cause the rocket body to be overturned and crashed occurs in the process of recovering the rockets executed before SpaceX for many times.

Besides, a method for reusing the hydrodynamic spacecraft by adopting a gliding landing mode is provided, and is mainly represented by a space shuttle in the United states. The space shuttle is vertically lifted off through the whole arrow, and after the load is conveyed to a preset target, the space shuttle horizontally glides and lands in a manner similar to that of the shuttle, so that the repeated use is completed. The mode has high technical difficulty, huge cost, small effective load ratio and extremely high maintenance cost, and the mainstream models are already in a retired state.

Therefore, the problem to be solved at present is to provide a rocket recovery device which is convenient to control, safe, reliable, cost-saving and convenient to reuse.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a liquid rocket, have convenient control, safe and reliable, can practice thrift the cost, be convenient for reuse advantage such as.

In order to achieve the above object, the utility model provides a following technical scheme: a liquid rocket comprises a rocket primary secondary, wherein the rocket primary secondary comprises a power tail cabin section, a parachute pack arranged in the power tail cabin section in a furled manner, and an explosion separation structure for connecting the power tail cabin section with the rocket primary secondary; wherein the detonation separating surface is located between the bottom of the tank of the rocket primary sub-stage and the power tail section; after the rocket is separated in one sub-stage, the explosion separation structure is detonated, so that the power tail cabin section is separated from the bottom of the storage tank along the explosion separation surface, and the parachute pack is opened to reduce the descending speed of the power tail cabin section.

Preferably, the blast separation structure comprises a separation blast bolt and a retainer, the retainer comprising a first portion fixedly connected to the power tail section outer casing and a second portion fixedly connected to a casing of the rocket first substage adjacent to the power tail section outer casing, the separation blast bolt securing the first and second portions to each other by penetrating the first and second portions.

Preferably, the separate explosion bolts are fixed by nuts from portions of the first and second portions, respectively, which protrude from opposite sides of each other.

Preferably, a plurality of the explosive separation structures are uniformly arranged along the circumferential direction of the position where the power tail cabin section is connected with the rocket first-stage.

Preferably, the power tail cabin section includes engine frame and parachute fixed bolster, the one end fixed connection of parachute package fixed bolster the engine frame is close to engine nozzle side, and the other end is used for setting up the parachute package.

Preferably, the parachute package contains a drogue parachute and a main parachute, the drogue parachute and the main parachute are configured not to interfere with each other when being opened, and the opening direction points to the side away from the engine frame.

Preferably, the power tail cabin section is further provided with landing legs or floating valves.

Preferably, the landing leg comprises a supporting seat, a connecting rotating shaft, a spring and a grounding plate; supporting seat one side is equipped with the bellying, and the opposite side connects the engine mounting bracket, be equipped with the through-hole on the bellying, it is equipped with the opening passageway to touch floor one end, connect the pivot and run through the through-hole with the opening passageway is in order to incite somebody to action touch the floor with supporting connection, thereby it configures to wind to touch the floor connect the pivot to rotate the spring housing establish connect in the pivot, in order supplementary it opens to touch the floor.

Preferably, the thickness of the end, far away from the connecting rotating shaft, of the touch floor is larger than the thickness of the end, close to the connecting rotating shaft, of the touch floor.

Preferably, the power tail cabin section comprises an adjustable tail wing, a servo mechanism, a controller and an attitude sensor, and the controller is electrically connected with the parachute pack, the servo mechanism and the attitude sensor respectively; after the power tail cabin section is separated from the rocket primary-secondary stage, the controller controls the servo mechanism to adjust the posture of the adjustable tail wing, so that the axis of the power tail cabin section is inclined relative to the gravity direction, and the controller controls the parachute pack to be opened according to the posture of the power tail cabin section detected by the posture sensor.

Compared with the prior art, the beneficial effects of the utility model are that: the liquid rocket comprises a rocket primary sub-stage, a power tail cabin section, a parachute pack and an explosion separation structure, wherein the bottom of a storage tank of the rocket primary sub-stage is connected with the power tail cabin section through the explosion separation structure, after the rocket primary sub-stage is separated, the explosion separation structure is detonated, so that the power tail cabin section is separated from the bottom of the storage tank along an explosion separation surface, the parachute pack located on the power tail cabin section is opened at the moment, the descending speed of the power tail cabin section is reduced, the power tail cabin section is ensured to safely descend, and then the recovery of the power tail cabin section is completed.

Drawings

FIG. 1 is a schematic view of a liquid rocket;

FIG. 2 is a schematic diagram of the power tail section and the recovery device of the present invention in a half-throw mode;

FIG. 3 is a schematic diagram of the separation of the power tail cabin section and the arrow body of the utility model;

FIG. 4 is a schematic view of the power tail cabin section of the utility model showing the opening of the speed reducing parachute and the turning;

FIG. 5 is a schematic view of the power tail compartment section of the present invention with the main umbrella opened and the air vane adjusted;

FIG. 6 is a schematic diagram of the landing leg popped up from the power tail compartment section of the present invention;

fig. 7 is a right side view of the pop-up landing leg of the present invention;

fig. 8 is a front view of the pop-up landing leg of the present invention;

FIG. 9 is a schematic structural view of the connecting shaft and the spring of the present invention;

fig. 10 is a top view of the fastener of the present invention;

FIG. 11 is a front view of the separation explosion bolt and the fastener of the present invention;

FIG. 12 is a front view of the landing platform of the present invention connected to a colloid layer;

FIG. 13 is a schematic view of a fixing hole of the present invention;

fig. 14 is a front view of the touch floor of the present invention.

Description of reference numerals:

1 rocket one-sub-stage 2 power tail cabin section

3 separation explosion bolt 4 adjustable tail wing device

5 second controller 6 multiple parallel engines

7 parachute bag 8 parachute fixing bracket

9 engine mounting frame 10 landing leg

11 oxidant main pipeline separating valve 12 fuel main pipeline separating valve

13 deceleration parachute 14 main parachute

15 landing platform 16 support base

17 connecting rotating shaft 18 spring

19 open channel touching floor 20

21 raised part 22 through hole

23 attachment hole of anchor 24

25 glue layer 26 fixing hole

27 raised column

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the spirit of the present invention will be described in detail with reference to the accompanying drawings, and any person skilled in the art can change or modify the techniques taught by the present invention without departing from the spirit and scope of the present invention after understanding the embodiments of the present invention.

The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention. Additionally, the same or similar numbered elements/components used in the drawings and the embodiments are used to represent the same or similar parts.

As used herein, the terms "first," "second," …, etc. do not denote any order or sequential importance, nor are they used to limit the invention, but rather are used to distinguish one element from another or from another element or operation described in the same technical language.

With respect to directional terminology used herein, for example: up, down, left, right, front or rear, etc., are simply directions with reference to the drawings. Accordingly, the directional terminology used is intended to be illustrative and is not intended to be limiting of the present teachings.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

As used herein, "and/or" includes any and all combinations of the described items.

As used herein, the terms "substantially", "about" and the like are used to modify any slight variation in quantity or error that does not alter the nature of the variation. Generally, the range of slight variations or errors modified by such terms may be 20% in some embodiments, 10% in some embodiments, 5% in some embodiments, or other values. It should be understood by those skilled in the art that the aforementioned values can be adjusted according to actual needs, and are not limited thereto.

Certain words used to describe the present application are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the present application.

Referring to fig. 1 and 2, an embodiment of the present invention provides a liquid rocket, including a rocket first-stage 1, a power tail cabin section 2, a parachute bag 7 and an explosion separation structure; the power tail cabin section 2 is connected with the rocket primary sub-stage 1 through an explosion separation structure, an explosion separation surface is positioned between the bottom of a storage tank of the rocket primary sub-stage and the power tail cabin section 2, and the parachute pack 7 is arranged on the power tail cabin section 2 in a furled manner; after the rocket first-stage 1 is separated, the explosion separation structure is detonated, so that the power tail cabin section 2 is separated from the bottom of the storage tank along the explosion separation surface, and the parachute package 7 is opened to reduce the descending speed of the power tail cabin section 2.

Specifically, the method comprises the following steps: this liquid rocket comprises rocket first substage 1, power tail cabin section 2, parachute package 7 and explosion separation structure, the storage tank bottom and the power tail cabin section 2 of rocket first substage 1 are connected through explosion separation structure, after rocket first substage 1 separates, explosion separation structure detonates, thereby power tail cabin section 2 separates along explosion separation face with the storage tank bottom, parachute package 7 that is located on power tail cabin section 2 this moment opens, reduce power tail cabin section 2 falling speed, guarantee power tail cabin section 2 safety descending, and then accomplish and retrieve power tail cabin section 2, this structure has convenient control, safe and reliable, can practice thrift the cost, can overhaul test, clearance, can used repeatedly power tail cabin section 2.

It is worth mentioning that as shown in fig. 1, 3, 10, 11, the explosion separating structure comprises the separation explosion bolt 2 and the retainer 23, the retainer 23 comprises a first portion fixedly connected with the outer shell of the power tail cabin 2 (i.e. the upper half of the retainer 23 shown in fig. 11) and a second portion fixedly connected with the shell of the rocket first sub-stage 1 adjacent to the outer shell of the power tail cabin 2 (i.e. the lower half of the retainer 23 shown in fig. 11), and the separation explosion bolt 2 fixes the first portion and the second portion to each other by penetrating the first portion and the second portion. The explosive bolt 3 is detonated and separated, so that the first part and the second part are separated, the separation of the power tail cabin section 2 is further completed, and the recovery of the subsequent power tail cabin section 2 is facilitated. It should be noted that, in order to fix the separation explosive bolt 2, the portions of the separation explosive bolt 2 protruding from the opposite sides of the first portion and the second portion are fixed by nuts, and it should be noted that, in order to facilitate the separation explosive bolt 2 to penetrate through the retainer 23, the retainer 23 is provided with a connection hole 24.

It should be noted that, as shown in fig. 2, the parachute package 7 is fixed to the power pod 2 by the parachute fixing bracket 8.

In the present embodiment, as shown in fig. 2, 3, 6, 7, 8, 9, and 14, in order to make landing of the power pod 2 more stable, landing legs 10 are provided on the power pod 2. The landing leg is connected to the power pod 2 via an engine mount frame 9, and the landing leg 10 is located on the upper part of the engine mount frame 9 (i.e. on the opposite side of the engine mount frame to the side on which the engine is mounted). It should be noted that, in order to facilitate the opening of the landing leg 10, the landing leg 10 is composed of a support base 16, a connecting shaft 17, a spring 18 and a ground contacting plate 19, a protruding portion 21 is disposed on one side of the support base 16, and the other side is connected to the engine mounting bracket 9, a through hole 22 is disposed on the protruding portion 21, an opening channel 20 is disposed at one end of the ground contacting plate 19, the connecting shaft 17 penetrates through the through hole 22 and the opening channel 20 to connect the ground contacting plate 19 with the support base 16, so that the ground contacting plate 19 is configured to rotate around the connecting shaft 17, and the spring 18 is sleeved on the connecting shaft 17 to assist. In order to fix the protruding column 27 conveniently, the protruding column 27 is in a cylindrical structure, and it should be mentioned that, in order to increase the bearing pressure of the protruding portion 21, the protruding portion 21 is designed to have a rectangular parallelepiped structure.

Fig. 1 and 8 are opened for facilitating the contact with the floor plate 19, and the thickness of the floor plate 19 at the end away from the connecting rotation shaft 17 is larger than that at the end close to the connecting rotation shaft 19. Because the thickness of the end, far away from the connecting rotating shaft 17, of the touch floor 19 is greater than the thickness of the end, close to the connecting rotating shaft 17, of the touch floor 19, the center of gravity of the touch floor 19 is not on the same straight line with the center of the supporting seat, and the center of gravity is located on the side, far away from the power tail cabin section 2. When the power tail cabin section is turned over (the nozzle of the engine is upward), the floor 19 rotates downwards by taking the connecting rotating shaft 17 as the center under the action of gravity in the vertical direction, and forms a certain included angle with the supporting seat 16. According to the stress analysis, the structure decomposes the gravity of the whole power tail cabin section, reduces the force of the power tail cabin section 2 in the vertical direction, and is beneficial to enabling the power tail cabin section 2 to land stably, and particularly, in the embodiment, the shape of the grounding plate 19 is similar to a trapezoidal structure.

It should be noted that, as shown in fig. 7 and 8, in the present embodiment, in order to make the connection between the boss portion 21 and the support seat 16 more tight, the both are welded. In the present embodiment, the boss 21 and the support seat 16 are independent components, but in the actual application, in order to make the connection between the boss 21 and the support seat 16 more tight and firm, the two may be designed to be integrally formed, and the process will not be described here.

It should be noted that, as shown in fig. 6, the landing leg 10 may be changed according to the landing environment, when the power pod 2 lands on the sea, the landing leg 10 may be changed into a floating valve, and when the power pod 2 lands on the desert, the landing leg 10 may not be installed on the power pod 2, and the process is not described one by one.

In this embodiment, as shown in fig. 2, the power pod 2 may include a housing, a plurality of parallel engines 6, an engine mount 9 and an adjustable tail device. The engine mounting frames 9 and the multiple parallel engines 6 are all positioned in the shell, the engine mounting frames 9 are positioned on the parachute bag 7, the parachute fixing support 8 and the upper parts of the multiple parallel engines 6 (under the condition that the rocket is upright in the forward direction), namely the parachute bag 7, the parachute fixing support 8 and the multiple parallel engines 6 are all arranged on the same side of the engine mounting frames 9. The two ends of the parachute fixing support 8 are respectively connected with the parachute bag 7 and the engine mounting support 9. For example, the parachute mounting bracket 8 may be located on a centerline of the engine mount frame 9 and near one side of the plurality of parallel engines 6, one end of the plurality of parallel engines 6 being connected to the engine mount frame 9 and the nozzle opening facing the other end away from the engine mount frame 9.

For example, as shown in fig. 2 and 5, the landing leg 10 may be a pop-up leg, one end of which is connected to the engine mounting frame 9 and is located on the side away from the parachute pack 7. The parachute package 7 is connected with a first controller electrically, and the first controller is used for detecting the posture of the power tail cabin section and controlling the opening of the parachute package 7. The adjustable tail device comprises an adjustable tail 4 and a second controller 5, wherein the second controller 5 is connected with the adjustable tail 4 through an electric lead. The adjustable tail 4 is partly located outside the power tail section casing and the second control 5 is located inside the casing. For example, the second controller 5 may be a tail servo controller for adjusting the attitude of the adjustable tail 4. For example, the first controller may set the angle of inclination of the power pod section and the second controller 5 adjusts the angle of the adjustable tail 4 accordingly according to the angle of inclination, so that the first controller controls the opening of, for example, a drogue after the angle of the power pod section reaches a set value.

For example, as shown in fig. 3 and 4, in the case that the power tail section 2 is not provided with an adjustable tail wing, the first controller may detect the falling posture of the power tail section in real time, and control the parachute to open when the axial direction of the power tail section 2 forms a certain angle with the gravity direction. After the parachute 13 is opened, since the falling speed of the parachute 13 under the action of the airflow is much smaller than that of the power pod section 2, the parachute 13 is quickly located above the power pod section and decelerates the power pod section 2 in the direction of gravity.

It should be particularly noted that, as shown in fig. 2, 8 and 13, in order to facilitate the adjustment of the position of the landing leg 10, a plurality of fixing holes 26 may be provided in the engine mount frame 9 to facilitate the fixing of the protruding columns 27, so that the landing leg 10 is firmly fixed.

Specifically, as shown in fig. 2, in order to reduce the cost, an oxidant main line separation valve 11 and a fuel main line separation valve 12 are arranged in a shell of the power tail section, so that the oxidant main line separation valve and the fuel main line separation valve are recovered together when the power tail section is recovered, the reuse is realized, and the cost is reduced.

Particularly, as shown in fig. 2, in the recovery process of the power tail section 2, in order to position the position of the power tail section 2 conveniently, a navigation positioner may be arranged in the casing, so that the position change of the power tail section is monitored in real time through communication between the navigation positioner and a ground signal receiver.

In the present embodiment, as shown in fig. 5 and 6, the parachute package 7 includes a drogue 13 and a main parachute 14, and the drogue 13 may be located outside the main parachute 14 and may be opened without interfering with each other. For example, the first controller may obtain the attitude of the power pod section 2 through a sensor, and when the axis direction of the power pod section 2 forms a certain angle with the gravity direction or the engine nozzle faces the side away from the ground, the first controller controls the drogue to open. The deceleration parachute 13 is used for adjusting the posture of the power pod section 2 and playing a deceleration role, so that the power pod section 2 is in a vertical state. When the engine of the power pod section 2 faces away from the ground and is perpendicular to the ground, the first controller controls the main umbrella 14 to open. The main parachute 14 is used for the deceleration of the power pod section 2, thereby ensuring the recovery of the entire apparatus.

In addition, as shown in fig. 2, 5 and 6, in practical application, the controller may control the parachute 13 to open when an angle between an extension line of the engine of the power pod section 2 and the ground is greater than 45 degrees, the parachute 13 is opened at a lower speed than the power pod section 2 due to gravity and air friction, and when the engine of the power pod section 2 faces away from the ground and is substantially perpendicular to the ground, the main parachute 14 is opened, thereby ensuring the recovery of the whole device.

As shown in fig. 1 and 12, in order to ensure safe recovery of the power tail section 2, a landing platform 15 may be installed at the landing of the power tail section 2. In the present embodiment, the landing platform 15 may have a square structure in its outer shape. In practical applications, the landing platform 15 may also be rectangular, circular, diamond-shaped, etc., and will not be described herein. It should be noted that, in order to reduce the pressure between the power pod 2 and the landing platform 15, a glue layer 25 may be provided on the upper surface of the landing platform 15. The colloid layer 25 plays a role of buffering when the power tail cabin section descends, and further the landing safety of the power tail cabin section 2 is guaranteed. Further, in order to prevent the colloid layer 25 from moving, the colloid 25 and the landing platform 15 are closely attached to each other and are adhesively connected.

For the convenience of separation, a plurality of explosive separation structures are uniformly arranged along the circumferential direction of the position where the power tail cabin section 2 is connected with the rocket-stage 1 as shown in fig. 3.

It should be noted that, as shown in fig. 2, the power boot section 2 includes an engine frame 9 and a parachute fixing bracket 8, one end of the parachute fixing bracket 8 is fixedly connected to the engine frame 9 near the engine nozzle side, and the other end is used for arranging the parachute pack 7.

In the present embodiment, it is worth mentioning that the connection means includes a screw connection, welding, riveting, etc., and will not be described in detail herein.

The foregoing is only an illustrative embodiment of the present invention, and any equivalent changes and modifications made by those skilled in the art without departing from the spirit and principles of the present invention should fall within the protection scope of the present invention.

Claims

1. A liquid rocket comprises a rocket first sub-stage and is characterized in that; the first sub-stage of the rocket comprises a power tail cabin section, a parachute pack arranged on the power tail cabin section in a furling manner and an explosion separation structure for connecting the power tail cabin section with the first sub-stage of the rocket; wherein the detonation separating surface is located between the bottom of the tank of the rocket primary sub-stage and the power tail section;

after the rocket is separated in one sub-stage, the explosion separation structure is detonated, so that the power tail cabin section is separated from the bottom of the storage tank along the explosion separation surface, and the parachute pack is opened to reduce the descending speed of the power tail cabin section.

2. A liquid rocket according to claim 1, wherein: the blast isolation structure includes a breakaway blast bolt and a retainer, the retainer including a first portion fixedly attached to the power pod section outer casing and a second portion fixedly attached to a shell of the rocket first substage adjacent the power pod section outer casing, the breakaway blast bolt securing the first portion and the second portion to one another by extending through the first portion and the second portion.

3. A liquid rocket according to claim 2, wherein: the portions of the separate explosion bolts respectively protruding from the first portion and the second portion on the opposite sides to each other are fixed by nuts.

4. A liquid rocket according to claim 2, wherein: and a plurality of the explosion separation structures are uniformly arranged along the circumferential direction of the position where the power tail cabin section is connected with the rocket first-stage.

5. A liquid rocket according to claim 1, wherein; the power tail cabin section includes engine frame and parachute fixed bolster, the one end fixed connection of parachute package fixed bolster the engine frame is close to the engine nozzle side, and the other end is used for setting up the parachute package.

6. A liquid rocket according to claim 5, wherein; the parachute package contains parachute and main umbrella, the parachute with main umbrella configuration is as mutual noninterference when opening, and the direction of opening point to one side far away from the engine frame.

7. A liquid rocket according to claim 1, wherein; and landing legs or floating valves are also arranged on the power tail cabin section.

8. A liquid rocket according to claim 7, wherein; the landing support leg comprises a support seat, a connecting rotating shaft, a spring and a ground contact plate; supporting seat one side is equipped with the bellying, and the opposite side connects the engine mounting bracket, be equipped with the through-hole on the bellying, it is equipped with the opening passageway to touch floor one end, connect the pivot and run through the through-hole with the opening passageway is in order to incite somebody to action touch the floor with supporting connection, thereby it configures to wind to touch the floor connect the pivot to rotate the spring housing establish connect in the pivot, in order supplementary it opens to touch the floor.

9. A liquid rocket according to claim 8, wherein; the touch floor is far away from the thickness of one end of the connecting rotating shaft is larger than the thickness of one end of the connecting rotating shaft.

10. A liquid rocket according to any one of claims 1-9 wherein said power tail capsule section comprises an adjustable tail wing, a servo mechanism, a controller and an attitude sensor, said controller being electrically connected to said parachute package, said servo mechanism and said attitude sensor, respectively;

after the power tail cabin section is separated from the rocket primary-secondary stage, the controller controls the servo mechanism to adjust the posture of the adjustable tail wing, so that the axis of the power tail cabin section is inclined relative to the gravity direction, and the controller controls the parachute pack to be opened according to the posture of the power tail cabin section detected by the posture sensor.