Method for reducing jet tub exposure during thrust direction control

Abstract

A method for thrust vector control of a vehicle utilizing jet tabs is presented. Jet tabs are used to create a lateral control moment on the vehicle by rotating the tabs into a rocket plume and varying the thrust vectoring angle. The method involves simultaneously rolling the vehicle during thrust vector control maneuvers to reduce the maximum exposure of the tabs to the rocket plume. The method allows for aggressive pitch-over maneuvers while reducing the risk of tab failure due to excessive exposure.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to thrust vector control systems, and more specifically to methods of using a thrust vector control system equipped with a jet tab assembly to control pitch-over maneuvers.

BACKGROUND ART

[0002] Pitch-over maneuvers are used to orient a vertically launched projectile in a desired direction immediately after launch or shortly after launch. Pitch-over maneuvers impose constraints on other projectile performance metrics, such as minimum and maximum engagement ranges, as well as the overall kinematics of the projectile including speed and maneuverability. Because the pitch-over maneuver occurs immediately after launch, the velocity of the projectile is relatively low.

[0003] Projectile control actuation systems typically utilize aerodynamic fins to control the velocity vector of the projectile during flight. However, due to the low initial velocity of the projectile immediately after launch, fin-based control is usually not effective in generating a moment large enough to achieve a significant pitch-over maneuver. Therefore, thrust vector control is used to control the projectile after launch to achieve stability and maneuverability during the low dynamic pressure period.

[0004] There are various methods for generating thrust vector control, including movable nozzles, thrust vanes, and jet tabs. For example, a jet tab assembly is mounted at the outlet end of the rocket nozzle of a projectile. It consists of a plurality of tabs that can be independently rotated into and out of the jet plume to vary the thrust angle as needed. When a single jet tab of the jet tab assembly rotates into the jet plume, a thrust deflection angle is generated within a single plane. By rotating various combinations of jet tabs into the jet plume, different thrust deflection angles are produced in various planes. The deflected thrust angle of the projectile generates a moment that can be used for lateral control of the projectile.

[0005] However, because there is a risk that one or more jet tabs in the jet tab assembly may be excessively exposed to the flame, several problems may arise with the jet tab assembly and pitch-over performance. Specifically, if one or more jet tabs in the jet tab assembly are excessively exposed to the flame during pitch-over maneuvers, the tabs may undergo tab ablation, resulting in a reduced effectiveness in generating the desired thrust deflection angle. In addition, if the jet tab assembly is damaged by heat, tab movement may be limited due to cracks in the jet tabs, slug between the jet tabs and the scraper ring, or warping of the scraper ring or shaft. Furthermore, there is a risk that the motor or electronics of the jet tab assembly may be damaged by heat. Any of these effects of excessive exposure of jet tabs will limit pitch-over maneuverability and the performance of the entire projectile.

[0006] Conventional solutions to these problems include incorporating ablation materials or other exotic materials, such as tungsten and composites, to withstand exposure to the jet flame, but these materials can be expensive and impractical. Other solutions include limiting the jet tub's exposure simply by limiting its pitch-over performance. [Overview of the Initiative]

[0007] This specification describes an improved thrust direction control method using jet tabs after launch. To reduce the maximum jet tab exposure of the projectile jet tab assembly to the projectile's exhaust flame after launch, the projectile is controlled to roll simultaneously with pitch-over maneuvers. Because the projectile is rolling, the lateral control device must continuously utilize various combinations of tabs to achieve the desired thrust angle deflection. In this way, the exposure of each jet tab to the projectile's exhaust flame during thrust direction control is more evenly distributed, and the maximum exposure of individual tabs is reduced.

[0008] Accordingly, according to an aspect of the present disclosure, a method for controlling the thrust direction of a projectile includes the steps of launching the projectile such that a flame exits from the exit end of the projectile's rocket nozzle, and generating a lateral control moment in the projectile by changing the thrust deflection angle of the flame. The method also includes the step of rolling the projectile at the same time as changing the thrust deflection angle of the flame.

[0009] According to embodiments of any paragraph(s) of this disclosure, changing the thrust deflection angle of the jet flame includes controlling the jet tub assembly of the projectile.

[0010] According to another embodiment of any paragraph(s) of the present disclosure, the jet tub assembly includes a plurality of jet tubs rotatably mounted on the exit end of the rocket nozzle of a projectile, and the step of controlling the jet tub assembly includes rotating one or more of the plurality of jet tubs into the projectile's jet flame exiting the exit end of the rocket nozzle of the projectile.

[0011] According to another embodiment of any paragraph(s) of this disclosure, launching a projectile includes launching the projectile vertically.

[0012] According to another embodiment of any paragraph(s) of this disclosure, the step of rolling the projectile begins before the step of changing the thrust deflection angle of the jet.

[0013] According to another embodiment of any paragraph(s) of this disclosure, the step of rolling the projectile begins after the step of changing the thrust deflection angle of the jet.

[0014] According to another embodiment of any paragraph(s) of this disclosure, the step of rolling the projectile begins concurrently with the step of changing the thrust deflection angle of the jet.

[0015] According to another embodiment of any paragraph(s) of this disclosure, the step of rolling the projectile includes rolling the projectile at a roll angular velocity that reduces the maximum exposure of any one of a plurality of jet tubs.

[0016] According to another aspect of the present disclosure, the projectile includes a thrust direction control device configured to change the thrust deflection angle of the flame emitted from the exit end of the rocket nozzle of the projectile after launch. The projectile also includes a roll control device configured to roll the projectile simultaneously with the change in the thrust deflection angle of the flame by the thrust direction control device.

[0017] According to any or more embodiments of the present disclosure, the projectile further includes a jet tub assembly. A thrust direction control device is configured to control the jet tub assembly to change the thrust deflection angle of the jet flame.

[0018] According to another embodiment of any paragraph(s) of this disclosure, the jet tub assembly is attached to the exit end of the rocket nozzle of the projectile.

[0019] According to another embodiment of any paragraph(s) of the present disclosure, the jet tub assembly includes a plurality of jet tubs rotatably mounted on the exit end of the rocket nozzle of the projectile, and the thrust direction control device is configured to rotate one or more of the plurality of jet tubs into the projectile's exhaust flame.

[0020] According to another embodiment of any paragraph(s) of the present disclosure, the roll control device is configured to cause the projectile to roll before the thrust direction control device is configured to begin changing the thrust deflection angle of the jet.

[0021] According to another embodiment of any paragraph(s) of the present disclosure, the roll control device is configured to start rolling the projectile after the thrust direction control device is configured to start changing the thrust deflection angle of the jet.

[0022] According to another embodiment of any one or more paragraphs of the present disclosure, the roll control device is configured to start rolling the flying object at the same time as the thrust direction control device is configured to start changing the thrust deflection angle of the jet flame.

[0023] In the following description and the accompanying drawings, certain exemplary embodiments described in the present disclosure are set forth in detail. However, these embodiments represent only a few of the various ways in which the principles of the present disclosure may be employed. Other objects, advantages and novel features will become apparent from the following detailed description when considered in conjunction with the drawings.

[0024] The accompanying drawings illustrate various aspects of the present disclosure. [Brief Description of the Drawings]

[0025] [Figure 1] It is a schematic diagram of a flying object. [Figure 2] It is an exploded schematic view of the jet tab assembly of the flying object of Figure 1. [Figure 3] It is a perspective view of the jet tab assembly of Figure 2. [Figure 4] It is a graph showing the tab exposure of four jet tabs on a jet tab assembly over time during a prior art pitch-over maneuver. [Figure 5] It is a graph showing the tab exposure of four jet tabs on a jet tab assembly over time during a pitch-over maneuver according to the method of the present disclosure. [Figure 6] It is a flowchart of a thrust direction control method for a flying object. [Mode for Carrying Out the Invention]

[0026] First, referring to Figure 1, the projectile 10 is depicted. The projectile 10 includes a projectile body 12 and a rocket nozzle 14 at the tail end 13 of the projectile body 12. The projectile 10 may further include a jet tub assembly 16 attached to the exit end 15 of the rocket nozzle 14, from which a flame 22 is emitted to propel the projectile during launch and flight. The projectile 10 includes a thrust direction control device 18, which is configured to generate a lateral control moment in the projectile and change the velocity vector of the projectile 10 after launch by changing the thrust deflection angle of the flame 22 emitted from the exit end 15 of the rocket nozzle 14, as will be described in more detail below. The projectile 10 also includes a roll control device 20, which is configured to roll the projectile 10 simultaneously with the change in the thrust deflection angle of the flame 22 by the thrust direction control device 18, as will be described in more detail below. It should be understood that the flying object 10 is not limited to the features described above and outlined, but may also include other features that have traditionally been included in the flying object 10.

[0027] As used herein, the term “control device” (e.g., “thrust direction control device 18” and “roll control device 20”) should be broadly interpreted to include systems having a processor capable of executing instructions. Such instructions may be embodied in software and / or hardware and / or in various computer-readable media, such as memory, ROM, RAM, etc. Software may include, but is not limited to, one or more computer or processor instructions that can be interpreted, compiled, and / or executed to cause a computer, processor, or other electronic device to perform a function, action, or behavior in a desired manner. Instructions may be embodied in various forms such as routines, algorithms, modules, methods, threads, or programs, for example, code from a separate application or dynamically or statically linked libraries. Software may also be implemented in various executable or loadable forms, including, but not limited to, standalone programs, function calls (local or remote), servlets, applets, instructions stored in memory, parts of an operating system, or other types of executable instructions. Those skilled in the art will understand that the form of software may be determined by, for example, the requirements of the desired application, the environment in which it will be run, or the requirements of the designer / programmer. They will also understand that computer-readable or computer-executable instructions can reside within a single logic or be distributed among two or more communication, collaborative, or parallel processing logics, and therefore can be loaded or executed in serial, parallel, massively parallel, and / or other ways.

[0028] The thrust direction control device 18 may be configured to change the thrust deflection angle of the jet flame 22, for example, using a jet tub assembly 16. Referring to Figures 2 and 3, the jet tub assembly 16 may include a plurality of jet tubs 24. For example, as shown, the jet tub assembly 16 may include four jet tubs 24. However, it should be understood that the configuration of four jet tubs 24 out of the plurality of jet tubs 24 is provided as a non-limiting example, and the jet tub assembly 16 may have more than four jet tubs 24 or fewer than four jet tubs 24. Each jet tub 24 of the plurality of jet tubs 24 is rotatably mounted to the exit end 15 of the rocket nozzle 14 of the projectile.

[0029] In any embodiment, the thrust direction control device 18 is configured to independently control each jet tub 24 inside and outside the flame, thereby variably controlling the thrust deflection angle of the flame 22 and thereby generating a lateral control moment in the projectile 10. For example, as described above with reference to a jet tub assembly used in the prior art, a thrust deflection angle can be generated in a single plane by rotating a single jet tub 24 and introducing it into the flame 22 exiting the outlet end 15 of the rocket nozzle 14. By rotating various combinations of more than one jet tub 24 and introducing them into the flame 22, various thrust deflection angles can be generated in various respective planes as desired for controlling the thrust deflection angle of the flame 22.

[0030] The roll control device 20 is configured to roll the projectile 10 simultaneously with the change in the thrust deflection angle of the thrust flame 22 by the thrust direction control device 18. For example, immediately after the launch of the projectile 10, as soon as the thrust direction control device 18 begins to change the thrust deflection angle of the thrust flame 22, the roll control device 20 is configured to begin rolling the projectile 10. In another embodiment, the roll control device 20 is configured to begin rolling the projectile 10 after the thrust direction control device 18 has begun to change the thrust deflection angle. Alternatively, the roll control device 20 is configured to begin rolling the projectile 10 before the thrust direction control device 18 begins to change the thrust deflection angle. Various roll schedules can provide various levels of advantages. For example, the roll control device 20 can command a roll angular velocity that results in the projectile roll direction completing one full rotation during pitch-over maneuvers. Alternatively, it may command a roll angular velocity that results in the projectile roll direction completing half a full rotation. It is important to understand that the greatest benefit of reducing the maximum exposure achieved depends on the application and needs to be optimized for the specific projectile and desired pitch-over performance.

[0031] The thrust direction control device 18 and the roll control device 20 work together to maintain the thrust deflection angle of the jet flame during pitch-over maneuvers. That is, when the projectile 10 rolls, the thrust direction control device 18 controls the multiple jet tabs 24 so that the exposure of the multiple jet tabs 24 to the jet flame 22 is distributed among the multiple jet tabs 24, rather than just to a single jet tab 24. For example, when the roll control device 20 rolls the projectile 10 to the first roll position, the thrust direction control device 18 rotates the first jet tab 24 of the multiple jet tabs 24 to enter the jet flame 22 in order to change the thrust deflection angle of the jet flame 22. When the roll control device 20 rolls the projectile 10 from the first roll position to the second roll position, the thrust direction control device 18 rotates the first jet tub to exit the flame 22 and rotates the second jet tub 24 adjacent to the first jet tub 24 to enter the flame 22, thereby maintaining the thrust deflection angle of the flame 22 and the thrust direction of the projectile 10 as the roll control device 20 rolls the projectile. In this way, the thrust direction control device 18 is configured to change and maintain the thrust deflection angle of the flame, and the roll control device 20 is configured to roll the projectile 10 during control by the thrust direction control device 18 so that the maximum exposure of any given jet tub 24 among the multiple jet tubs 24 is reduced and distributed among the multiple jet tubs 24.

[0032] Figure 4 illustrates a graph showing the tab exposure (y-axis) at each of the four jet tabs within a jet tab assembly of a conventional projectile during pitch-over maneuvers. As shown in the figure, over time (x-axis), one of the jet tabs receives significantly more exposure to the flame than the other jet tabs. This can lead to problems associated with jet tab overexposure, as described above. In contrast, Figure 5 illustrates a graph showing the tab exposure (y-axis) at each of the four jet tabs within a jet tab assembly, such as a jet tab assembly 16 of a projectile 10 using the thrust direction control device 18 and roll control device 20 described herein. As shown in the figure, over time (x-axis) during pitch-over maneuvers, the exposure of the jet tabs 24 to the flame 22 is more evenly distributed across each of the four jet tabs 24. For example, in the graph shown, a 34% reduction in maximum tab exposure is achieved at a 60-degree roll during pitch-over maneuvers. This reduction keeps the maximum exposure below the specified limit, thus enabling the desired pitch-over performance without the risk of jet tub assembly failure.

[0033] Figure 6 shows a flowchart of a thrust direction control method 100 for a projectile such as the projectile 10 described above. Method 100 includes a step 102 of launching the projectile so that a flame exits from the exit end of the projectile's rocket nozzle. The step 102 of launching the projectile may include, for example, launching the projectile vertically so that thrust direction control is required to change the projectile's velocity vector.

[0034] Method 100 then includes step 104 of generating a lateral control moment that changes the velocity vector of the projectile by changing the thrust deflection angle of the jet flame. Step 104 of changing the thrust deflection angle of the jet flame may include controlling the jet tub assembly of the projectile, for example, the aforementioned jet tub assembly 16. The jet tub assembly may include a plurality of jet tubs rotatably mounted on the exit end of the rocket nozzle of the projectile. Thus, the step of controlling the jet tub assembly may include rotating one or more of the jet tubs to enter the jet flame of the projectile exiting from the exit end of the rocket nozzle of the projectile.

[0035] Next, method 100 includes step 106 of rolling the projectile at the same time as step 104 of changing the thrust deflection angle of the jet tub assembly. By simultaneously changing the thrust deflection angle of the jet tub assembly and rolling the projectile, the exposure of any one of the jet tubs can be distributed among all of the jet tubs, so that none of the jet tubs reach their maximum exposure limit and thus do not cause the associated problems described above. Therefore, the maximum exposure of any one of the jet tubs can be reduced.

[0036] While the above disclosure has illustrated and described certain preferred embodiments, it will be apparent to those skilled in the art that equivalent changes and modifications will be conceivable by reading and understanding this specification and the accompanying drawings. In particular, with respect to the various functions performed by the aforementioned elements (components, assemblies, devices, compositions, etc.), the terms used to describe such elements (including references to “means”) are intended, unless otherwise specified, to correspond to any element that performs a particular function of the described element (i.e., functionally equivalent), even if it is not structurally equivalent to the disclosed structure that performs the function in the typical embodiment or embodiment(s) illustrated herein. In addition, while certain features have been described above with respect to only one or more of the several illustrated embodiments, such features may be combined with one or more other features of other embodiments so as to be desirable and advantageous for any given or particular application.

Claims

1. A method for controlling the thrust direction of a flying object, The projectile is launched such that the flame exits from the exit end of the rocket nozzle of the projectile, By changing the thrust deflection angle of the aforementioned flame, a lateral control moment is generated in the flying object. The thrust deflection angle of the aforementioned flame is changed, and at the same time, the flying object is made to roll. This includes the following steps: Changing the thrust deflection angle of the flame includes controlling the jet tub assembly of the projectile. The jet tub assembly includes a plurality of jet tubs rotatably mounted on the exit end of the rocket nozzle of the projectile, and the step of controlling the jet tub assembly includes rotating one or more of the plurality of jet tubs into the jet flame of the projectile exiting from the exit end of the rocket nozzle of the projectile, A method comprising the step of rolling the projectile, wherein the projectile is rolled at a roll angular velocity that reduces the maximum exposure of any one of the plurality of jet tubs.

2. The method according to claim 1, wherein launching the projectile includes launching the projectile in a vertical direction.

3. The method according to claim 1 or 2, wherein the initiation of the step of rolling the projectile begins before the initiation of the step of changing the thrust deflection angle of the jet, such that the changing of the thrust deflection angle of the jet and the rolling of the projectile occur simultaneously.

4. The method according to claim 1 or 2, wherein the initiation of the step of rolling the projectile begins after the initiation of the step of changing the thrust deflection angle of the jet, such that the changing of the thrust deflection angle of the jet and the rolling of the projectile occur simultaneously.

5. The method according to claim 1 or 2, wherein the step of rolling the flying object begins simultaneously with the step of changing the thrust deflection angle of the jet.

6. It is a flying object, A thrust direction control device configured to change the thrust deflection angle of the flame emitted from the exit end of the rocket nozzle of the projectile after the projectile has been launched, A roll control device configured to roll the flying object simultaneously with the change in the thrust deflection angle of the flame by the thrust direction control device, Jet tub assembly and Includes, The thrust direction control device is configured to control the jet tub assembly to change the thrust deflection angle of the jet flame, The jet tub assembly includes a plurality of jet tubs rotatably mounted on the exit end of the rocket nozzle of the projectile, and the thrust direction control device is configured to rotate one or more of the plurality of jet tubs into the jet flame of the projectile. The roll control device is configured to roll the projectile at a roll angular velocity that reduces the maximum exposure of any one of the plurality of jet tubs.

7. The projectile according to claim 6, wherein the roll control device is configured to start rolling the projectile before the thrust direction control device is configured to start changing the thrust deflection angle of the flame, so that the change in the thrust deflection angle of the flame and the rolling of the projectile occur simultaneously.

8. The projectile according to claim 6, wherein the roll control device is configured to start rolling the projectile after the thrust direction control device is configured to start changing the thrust deflection angle of the flame, so that the change in the thrust deflection angle of the flame and the rolling of the projectile occur simultaneously.

9. The projectile according to claim 6, wherein the roll control device is configured to cause the thrust direction control device to begin changing the thrust deflection angle of the jet, and at the same time, to cause the projectile to begin rolling.

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