A multi-station rotation and uniform distribution universal core stage multi-engine parallel assembly method

Abstract

A multi-station rotationally evenly distributed universal core-stage multi-engine parallel assembly method is characterized by: first, a large rocket is hoisted onto a rocket body docking vehicle; second, the engine at the center is flipped to a horizontal posture and transported to an initial docking position; third, the docking posture of the engine is adjusted by the docking vehicle, and the docking surfaces are fitted by adjusting the posture; fourth, the bolts are inserted and tightened to assemble the engine to the final position; fifth, the engine docking vehicle is withdrawn; sixth, the engine at the edge station is flipped to a horizontal posture, placed on the engine docking vehicle, and transported to the initial docking position of the docking station at the bottom edge of the rocket body, and steps three to five are repeated to complete the installation of the engine at the edge station; the present invention adopts a 6-degree-of-freedom attitude adjustment docking vehicle to adjust the position of the docked engine, which solves the problem that the hoisting engine hoist will interfere with other engines, and can achieve faster and safer position adjustment and completion of docking assembly.

Description

Technical Field

[0001] The present invention belongs to the technical field of large aircraft assembly, in particular to a method for docking multiple engines of a large rocket, specifically a method for parallel assembly of multiple core-stage engines with multi-station rotation and uniform distribution. Background Art

[0002] Currently, new large rockets generally tend to adopt densely arranged multiple engines in parallel to improve the overall driving capability. For example, the new generation of manned lunar launch vehicles adopts a three-and-a-half-stage configuration with a total length of about 90 meters, and is bundled with two boosters that are basically the same as the core stage. The takeoff weight is about 2,200 tons. Among them, the core stage adopts a diameter of 5 meters and is equipped with 7 liquid oxygen-kerosene engines with a ground thrust of 125 tons, of which 3 engines are bidirectional swing engines. For details, see: Zhang Zhi, Xu Hongping, Deng Xinyu, et al., "Overall Plan and Key Technologies of the New Generation of Manned Lunar Launch Vehicles [J]". Manned Spaceflight, 2022, 28(4): 427-432.

[0003] A parallel rocket engine is a higher-thrust rocket engine composed of multiple rocket engines mounted parallel to each other on a common frame. The advantages of a parallel rocket engine are that it can achieve greater thrust using smaller engines and can control the flight trajectory of the aircraft by swinging the independent engines. Because it can utilize already developed rocket engines or only requires a smaller-thrust rocket engine, parallel rocket engines can save development costs and shorten the development cycle.

[0004] Traditionally, to ensure reliability, parallel engines are limited to a limited number, typically two or four. Therefore, heavy-lift rockets require large engines. However, large engines are challenging to design and more complex to manufacture. The disadvantages of large engines are the advantages of small engines. Small engines can be mass-produced using established processes, which not only improves production efficiency and reduces costs, but also enables structures that are impossible with traditional methods. Consequently, in recent years, aerospace companies, led by US company SpaceX, have launched super-heavy-lift rockets featuring a significant number of parallel engines, some as numerous as 29 engines. Modern engineering management and quality control technologies have significantly improved the reliability of rocket engines, making sudden engine failures, a common occurrence in the early days of the aerospace industry, a rare occurrence today. It has been estimated that paralleling multiple engines can achieve over 100% reliability. This means that if an individual engine fails, it can be shut down, while the remaining engines increase thrust and balance torque to ensure the rocket's flight. With the success of SpaceX's Falcon series of heavy-lift rockets, the multi-parallel engine layout has become increasingly popular.

[0005] Traditionally, the docking of a rocket engine and rocket body is done by manually manipulating the joint using a sling, hoisted by a gantry crane, and manually controlled. This approach offers low cost and high flexibility for small-batch production rockets.

[0006] However, the latest rocket bodies, both domestically and internationally, such as SpaceX's Falcon, tend to use multiple low-power, economical rocket engines connected in parallel to provide high driving force. This allows for faster and more economical propulsion of high-power rockets. However, due to the dense arrangement of multiple engines, this method is no longer able to meet the requirements of engine docking and installation due to the ease of interference between traditional hoisting equipment and already installed engines, and the shaking of the hoisting can easily damage the already installed engines. For rockets with multiple engines in parallel (generally more than five engines), the engine compartment contains a large number of products, and the weight and volume of servo mechanisms, accumulators, and various pipelines far exceed those of traditional models. The engine docking process is closely related to the final assembly of products in the engine compartment. At the same time, final assembly in the engine compartment faces problems such as dangerous high-altitude operations, difficult operation in confined spaces, and limited load-bearing points, posing a significant challenge to the reliability of the final assembly and the safety of the products.

[0007] The need for parallel assembly of multiple engines presents challenges, including positioning and batch installation, as well as ensuring accessibility and precision within confined spaces. Therefore, given the widespread trend toward densely packed parallel drive systems for new large rockets, new engine docking and installation methods are needed. Summary of the Invention

[0008] The present invention aims to address the interference issues that often occur during vertical installation of multiple engines in parallel due to the compact workspace. This invention proposes a method for parallel assembly of multiple universal core-stage engines with multi-station rotation and uniform distribution. Specifically, it addresses the installation sequence, station conversion, and adjustment methods for docking and assembling densely packed engines on large rockets, which can easily cause interference due to the compact workspace.

[0009] The technical solution of the present invention is:

[0010] A multi-station rotation and uniform distribution type universal core stage multi-engine parallel assembly method is characterized by:

[0011] First, the large rocket body is hoisted horizontally onto the body docking vehicle;

[0012] Second, flip the central engine to a horizontal position, place it on the engine docking vehicle, and transport it to the initial docking position at the central workstation;

[0013] Third, the docking position of the engine is adjusted by the docking vehicle. Based on the manually or automatically measured position, the motion axis of the docking vehicle is interactively or automatically driven to align the docking surfaces.

[0014] Fourth, insert and tighten the bolts to assemble the engine to its final position;

[0015] Fifth, exit the engine docking vehicle;

[0016] Sixth, flip the edge station engine to a horizontal position, place it on the engine docking vehicle, and move it to the initial docking position of the edge docking station at the bottom edge of the rocket body. Repeat steps 3 to 5 to complete the installation of the edge station engine.

[0017] Seventh, by adjusting the rocket body docking vehicle, rotate the new symmetrical engine docking position to the bottom docking station;

[0018] Eighth, repeat step six to complete the engine docking at all edge stations.

[0019] Furthermore, the docking equipment system should have the following components:

[0020] A rocket body docking vehicle, which is used to drive the rocket body to roll in order to change the specific position of the edge docking station

[0021] An engine docking vehicle is used to provide six degrees of freedom adjustment: X (along the rocket body heading, that is, the direction of the engine docking vehicle's advance and retreat), Y (the ground is in a right-handed coordinate system with the X and Z directions), Z (perpendicular to the ground direction), A (around X, providing engine roll motion for aligning the connection hole position), B (around Y, providing engine pitch motion for docking surface bonding), and C (around Z, providing engine yaw motion for docking surface bonding).

[0022] A handheld device is provided for interactively providing input of six-degree-of-freedom motion.

[0023] A control system is used to analyze the input of the handheld device or automatically measure the position of the docking surface, and then control the docking vehicle to adjust its posture.

[0024] Furthermore, for the engine docking vehicle, in order to adapt to the height adjustment requirements of the central docking station and the edge docking station, it is possible to consider using a fixed-height bracket to switch between the two stations. This can avoid the difficulties caused by large height differences (often greater than 2 meters) to the design of the docking vehicle.

[0025] Beneficial effects of the present invention:

[0026] This invention addresses the technical requirements for parallel docking of densely packed engines on large rockets and provides a method for assembling uniformly distributed multi-engine large rockets. This method involves the station conversion of multiple engines during the docking process, the composition of the docking system, and the docking method. It has the following significant advantages:

[0027] First, this method uses a 6-degree-of-freedom attitude adjustment docking vehicle to adjust the position of the docking engine, which solves the problem that the hoisting engine hoist will interfere with other engines, and can achieve faster and safer position adjustment and completion of docking assembly.

[0028] Secondly, this method converts the uniformly distributed engine into a docking station by rotating the rocket body. Therefore, the station can be determined and installed by dividing the inner and outer circles according to the different rotation radius. It can be completed by providing supports of different docking heights. Figure 1 Of the 7 engines, 6 have the same radius from the center, so they can be divided into 2 stations at different heights. Similarly, similar to the docking of the 31 engines of the Starship SpaceX, such as Figure 3 As shown, it can be divided into 3 circles and 3 stations according to different uniformly distributed radii to achieve docking.

[0029] Third, the present invention can be used to be installed on various large aircraft, including but not limited to large rockets, when approximately evenly distributed universal core-stage multiple engines are assembled in parallel, multi-station rotation is used to solve the problem of interference that is prone to occur due to the compact working space.

[0030] Fourthly, the present invention creatively changes the traditional vertical installation to horizontal installation, which greatly simplifies the installation equipment, not only ensures the installation accuracy, but also greatly improves the installation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the center docking station and the edge docking station of the present invention.

[0032] Figure 2 It is a schematic diagram of the composition of the docking equipment system of the present invention.

[0033] Figure 3 An example of the uniformly distributed rocket engine station arrangement of the present invention.

[0034] Figure 4 It is the sensor deployment and installation of the present invention.

[0035] Figure 5 It is a schematic diagram of detecting the directional deviation of the engine mounting surface and the rocket body mounting surface according to the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings and examples.

[0037] like Figure 1-5 shown.

[0038] A multi-station rotationally evenly distributed universal core stage multi-engine parallel assembly method includes the following: Step 1, placing the rocket body on the rocket body docking vehicle. If the rocket engine is heavy, it is easy to cause load imbalance during the installation process, and counterweight blocks should be added at the edge stations.

[0039] In the second step, the operator first places the central engine on the engine docking vehicle at the pre-installation station, positions and locks it, and adjusts it to the initial height of the central docking station;

[0040] Step 3: Use a tractor or other similar vehicle to push the engine docking vehicle to the installation location, generally about 50mm from the final position;

[0041] In step 4, the operator uses the control interface (including the handheld device) to activate the X-axis, Y-axis, Z-axis, yaw axis, pitch axis, and roll axis to the specified position, and repeatedly adjusts the position until the docking surfaces are in contact and the bolt holes on the docking surfaces are aligned;

[0042] The docking posture adjustment process includes two modes. One is manual observation and interactive posture adjustment. The specific steps are:

[0043] (4.1) Adjust the X axis so that the engine and the hull docking area are as close as possible (generally speaking, in the initial docking position, the deviations of the Y axis, Z axis and the three rotation axes are not large, which is basically the size of the error);

[0044] (4.2) Adjust the Y and Z axes so that the axis positions on the engine and the rocket body docking flange coincide with each other;

[0045] (4.3) Adjust the roll axis so that the axes of the mounting holes on the engine and rocket body flanges coincide with each other;

[0046] (4.4) Adjust the yaw and pitch axes so that the mating surfaces of the engine and rocket body flanges are parallel;

[0047] (4.5) Adjust the X axis so that the engine and the rocket body flange fit together.

[0048] Another automatic mode is to calculate the posture deviation and make automatic adjustments by adding sensor detection. A feasible sensor deployment and installation method is as follows: Figure 4 The posture detection module shown here consists of a mounting plate with four mounting holes selected on the engine docking surface. Four locating pins are located at the corresponding positions to facilitate the fixing of the entire detection component to the corresponding position on the engine docking surface. Three to four laser ranging sensors (at least three, four recommended) are deployed on the mounting plate to measure the position of the rocket body's engine mounting plane to determine the attitude of the engine docking surface relative to the rocket body. In addition, one or more visual cameras are deployed to detect the corresponding mounting hole positions on the rocket body to ensure that the rocket body and engine mounting holes are aligned.

[0049] The specific steps for posture adjustment in automatic mode are:

[0050] (4.1) Install the posture detection module (including the laser ranging sensor and hole position detection camera) on the engine docking surface using the selected mounting holes.

[0051] (4.2) Manually or automatically adjust the X-axis so that the engine and the ship docking area are close to the detection position (i.e., the distance between the engine and the rocket body is the thickness of the posture detection module plus the rated measurement distance, recommended to be about 20mm);

[0052] (4.3) The visual camera detects the position deviations ⊿x and ⊿y of the corresponding holes, and then the equipment automatically adjusts the deviations along the X and Y axes to align the holes.

[0053] (4.4) Use laser rangefinder to detect the distance and direction deviation between the engine mounting surface and the rocket body mounting surface, such as Figure 5 As shown;

[0054] The detection method is as follows:

[0055] Assume that the installation positions of the four laser displacement sensors are Si (i=1, 2, 3, 4) and the installation angles are Ni (i=1, 2, 3, 4). The sensors detect the corresponding points Pi (i=1, 2, 3, 4) on the rocket installation surface, and the corresponding detection distances are di (i=1, 2, 3, 4).

[0056] In the docking device coordinate system OXYZ, the installation position Si and the installation angle Ni are known, and the measured distance di can be read from the sensor detection data. Then, the position Pi of the detection point (i = 1, 2, 3, 4) can be calculated, as shown in formula (1).

[0057]

[0058] The direction of the rocket body installation plane is n P , the direction of the engine mounting surface is n S ,but:

[0059]

[0060]

[0061] For the four laser sensors, due to redundancy, further judgment can be made:

[0062]

[0063] If n Pi Four values ​​and n S The difference is not big, so nO Take the average of the four values; if there is a problem with the detection data of one of the sensors (for example, it is not aligned with the docking surface, or there is a foreign object on the docking surface, etc.), then the sum is close to n S The i-th value n Pi It is accurate, and it can be judged that the data corresponding to the sensor of the i diagonal is problematic, and an alarm can be issued and it is recommended to follow n Pi Adjustment.

[0064] (4.5) The equipment mainly adjusts the yaw axis and pitch axis so that n S and n P Consistent, that is, the butt joint surfaces are parallel;

[0065] If you need to further calculate the rotation angle, then:

[0066]

[0067] The vector form of formula (5) can be decomposed into three equations, and the corresponding yaw axis, pitch axis, and roll axis deflection angles can be solved.

[0068] (4.6) Use the visual camera again to detect the position deviation of the corresponding holes ⊿x and ⊿y. If there is any deviation, the device automatically adjusts the deviation along the X and Y axes to align the holes;

[0069] (4.7) Remove the posture detection module, and the equipment automatically adjusts the distance between the joint surfaces (usually the X axis) so that the joint surfaces fit together and the hole positions correspond, and then enters the next step of installing bolts and fasteners.

[0070] Step 5: Install the connecting bolts and complete the docking. After the docking installation is completed, the operator disconnects the engine and loosens the hanger fixing bolts;

[0071] Step 6: The operator returns the docking mechanism to its initial state and waits for the next step through the control program interface;

[0072] Step 7: Adjust the engine docking vehicle to the initial height of the edge docking station (due to the large difference in Z direction between the center and edge stations, this step may require the use or adjustment of auxiliary supports);

[0073] Step 8. If there is a counterweight, remove it and repeat steps 2 to 6 to install the edge engine;

[0074] Step 9: After installing one rocket, use the rocket body docking vehicle to drive the rocket body to rotate 180 degrees and move the symmetrical installation position to the edge engine installation station. If there is a counterweight, it should be removed and the symmetrical engine should be installed;

[0075] Step 10: Complete the installation of all engines in sequence.

[0076] The docking device used in the present invention is as follows Figure 2 As shown, it includes:

[0077] A rocket body docking vehicle is used to drive the rocket body to roll so as to change the specific position of the edge docking station.

[0078] An engine docking vehicle is used to provide six degrees of freedom adjustment: X (along the rocket body heading, that is, the direction of the engine docking vehicle's advance and retreat), Y (the ground is in a right-handed coordinate system with the X and Z directions), Z (perpendicular to the ground direction), A (around X, providing engine roll motion for aligning the connection hole position), B (around Y, providing engine pitch motion for docking surface bonding), and C (around Z, providing engine yaw motion for docking surface bonding).

[0079] A handheld device is provided for interactively providing input of six-degree-of-freedom motion.

[0080] A control system is used to analyze the input of the handheld device or automatically measure the position of the docking surface, and then control the docking vehicle to adjust its posture.

[0081] Furthermore, for the engine docking vehicle, in order to adapt to the height adjustment requirements of the central docking station and the edge docking station, it is possible to consider using a fixed-height bracket to switch between the two stations. This can avoid the difficulties caused by large height differences (often greater than 2 meters) to the design of the docking vehicle.

[0082] The parts not involved in the present invention are the same as the existing technology or can be implemented by using the existing technology.

Claims

1. A method for assembling multiple engines in parallel with a general core stage and uniformly distributed multi-station rotation, characterized by: It includes the following steps: First, the large rocket body is hoisted horizontally onto the body docking vehicle; Second, flip the central engine to a horizontal position, place it on the engine docking vehicle, and transport it to the initial docking position at the central workstation; Third, the docking position of the engine is adjusted by the docking vehicle. Based on the manually or automatically measured position, the motion axis of the docking vehicle is interactively or automatically driven to align the docking surfaces. Fourth, insert and tighten the bolts to assemble the engine to its final position; Fifth, exit the engine docking vehicle; Sixth, flip the edge station engine to a horizontal position, place it on the engine docking vehicle, and move it to the initial docking position of the edge docking station at the bottom edge of the rocket body. Repeat steps 3 to 5 to complete the installation of the edge station engine. Seventh, by adjusting the rocket body docking vehicle, rotate the new symmetrical engine docking position to the bottom docking station; Eighth, repeat step six to complete the docking of engines at all edge stations; Controlling the docking vehicle to adjust its posture includes manual observation interactive posture adjustment mode and automatic posture adjustment mode; the manual observation interactive posture adjustment mode includes the following steps: (1) Adjust the X-axis so that the engine and the rocket body docking area are as close as possible; (2) Adjust the Y and Z axes so that the axis positions on the engine and the rocket body docking flanges coincide with each other; (3) Adjust the roll axis so that the axes of the mounting holes on the engine and rocket body flanges coincide with each other; (4) Adjust the yaw and pitch axes so that the mating surfaces of the engine and rocket body flanges are parallel; (5) Adjust the X-axis so that the mating surfaces of the engine and the rocket body are aligned; The automatic posture adjustment mode includes the following steps: (1) On the engine docking surface, use the selected mounting holes to locate and install the posture detection module, which includes a laser ranging sensor and a hole position detection camera; (2) Manually or automatically adjust the X-axis so that the engine and rocket body docking area is close to the detection position. That is, the distance between the engine and rocket body is the thickness of the posture detection module plus the rated measurement distance, which is 20 mm. (3) Using a visual camera, the corresponding hole position deviations ⊿x and ⊿y are detected, and then the device automatically adjusts the deviations along the X and Y axes to align the holes; (4) Detecting the distance and directional deviation between the engine mounting surface and the rocket body mounting surface using a laser ranging sensor; The detection method is as follows: Assume that the installation positions of the four laser displacement sensors are Si (i = 1, 2, 3, 4) and the installation angles are Ni (i = 1, 2, 3, 4). The sensors detect the corresponding points Pi (i = 1, 2, 3, 4) on the rocket installation surface, and the corresponding detection distances are di (i = 1, 2, 3, 4). In the docking equipment coordinate system OXYZ, the installation position Si and installation angle Ni are known, and the measured distance di can be read from the sensor detection data. Then the position Pi (i = 1, 2, 3, 4) of the detection point is calculated as shown in formula (1); The direction of the rocket body installation plane is n P , the direction of the engine mounting surface is n S ,but: For the four laser sensors, due to redundancy, further judgment can be made: If n Pi Four values ​​and n S The difference is not big, so n P Take the average of the four values; if there is a problem with the detection data of one of the sensors, such as not matching the docking surface, or there is a foreign object on the docking surface, then the sum is close to n S The i-th value n Pi It is accurate. It can be judged that the data corresponding to the sensor of the i diagonal is problematic. It will alarm and suggest to follow n Pi Adjustment; (5) The equipment mainly adjusts the yaw axis and pitch axis so that n S and n P Consistent, that is, the butt joint surfaces are parallel; If you need to further calculate the rotation angle, then: The vector form of formula (5) is decomposed into three equations, and the corresponding yaw axis, pitch axis, and roll axis deflection angles are solved; (6) Use the visual camera again to detect the position deviation of the corresponding hole ⊿x and ⊿y. If there is any deviation, the equipment automatically adjusts the deviation along the X and Y axes to align the hole positions; (7) Remove the posture detection module, and the equipment automatically adjusts the distance between the docking surfaces so that the docking surfaces fit together and the hole positions correspond, and then enters the next step of installing bolt fasteners.

2. The method according to claim 1, wherein: Equipment used in the engine assembly process includes: A rocket body docking vehicle, which is used to drive the rocket body to roll in order to change the specific position of the edge docking station; An engine docking vehicle, used to provide six degrees of freedom adjustment; A handheld device for interactively providing six-degree-of-freedom motion input; A control system is used to analyze the input from the handheld device or automatically measure the position of the docking surface, and then control the docking vehicle to adjust its posture.

3. The method according to claim 2, wherein: The engine docking vehicle should adapt to the height adjustment requirements of the central docking station and the edge docking station, and should use a fixed height bracket to switch between the two stations, so as to avoid the difficulties caused by the large height difference to the design of the docking vehicle.

4. The method according to claim 3, wherein: The large height difference is a height difference of at least 2 meters.

5. The method according to claim 2, wherein: The six degrees of freedom adjustment include the X direction, i.e., the direction along the heading of the rocket body and the forward and backward direction of the engine docking vehicle, the Y direction, i.e., the direction of the right-hand coordinate system with the X and Z directions, the Z direction, i.e., the direction perpendicular to the ground, the A direction, i.e., providing the engine roll motion around the X axis for aligning the connection hole position, the B direction, i.e., providing the engine pitch motion around the Y axis for docking surface fit, and the C direction, i.e., providing the engine yaw motion around the Z axis for docking surface fit.

6. The method according to claim 1, wherein: The detection sensor is installed on the mounting plate. At the same time, 4 mounting holes are selected on the engine docking surface, and 4 positioning pins are set at the corresponding positions to facilitate fixing the entire detection sensor component at the corresponding position of the engine docking surface; 3 to 4 laser ranging sensors are deployed on the mounting plate to measure the position of the rocket body where the engine is installed to determine the posture of the engine docking surface relative to the rocket body; one or more visual cameras are deployed to detect the corresponding mounting hole positions on the rocket body to ensure that the hole positions of the rocket body and the engine mounting holes correspond.

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