Fault Control Reconfiguration Method for Servo Mechanism of Multi-engine Launch Vehicle

Abstract

The present invention discloses a method for reconstructing the control of a servo mechanism failure of a multi-engine parallel-connected launch vehicle, which belongs to the technical field of launch vehicle engine control. By establishing a reasonable engine swing model, the swing angle constraint on other engines after the servo mechanism failure of the multi-engine parallel-connected engine is calculated. Thus, the available swing angle of the servo mechanism that can be used to control the attitude of the launch vehicle is obtained. Then, based on the available swing angle of the servo mechanism, the swing angle required for the attitude control is allocated to each servo mechanism, and the control reconstruction is completed. The present invention can solve the problem that when a multi-engine parallel-connected launch vehicle fails in a servo mechanism, the control reconstruction can be completed without shutting down the engine, and the collision of the engines can be avoided.

Description

Technical Field

[0001] The invention relates to the technical field of launch vehicle engine control, and in particular to a fault control reconstruction method for a multi-engine parallel-connected launch vehicle servo mechanism. Background Art

[0002] A multi-engine parallel launch vehicle refers to a launch vehicle that has multiple rocket engines arranged in parallel to provide thrust. A typical multi-engine parallel launch vehicle uses multiple identical liquid rocket engines arranged densely at the bottom of the rocket, and the engines work to provide thrust for the launch vehicle. There are two sets of servo mechanisms installed at a 90-degree angle on both sides of the engine, which can control the bidirectional swing of the liquid rocket engine. By changing the thrust direction through engine swing, a control torque is generated to control the rocket flight. After the engine servo mechanism fails, the engine swing cannot be controlled, and thus the thrust direction cannot be controlled or changed. The control strategy needs to be reconstructed to allow the rocket to fly normally.

[0003] When a launch vehicle engine servo mechanism fails, the corresponding engine is usually shut down, and redundant control is performed based on the remaining engines. By redistributing the swing angle of the engine servo mechanism, the remaining engines can provide the control torque required by the launch vehicle. For launch vehicles with multiple parallel engines, it is also possible to shut down the failed (servo) engine and the symmetrical side engine to achieve redundant control.

[0004] The existing method of reallocating the swing angle of the engine servo mechanism can be applied to launch vehicles with large engine spacing and a small number of engines. For multi-engine parallel engine launch vehicles, multiple identical liquid rocket engines are densely arranged at the bottom of the rocket. The use of the method of reallocating the swing angle of the engine servo mechanism may cause the problem of engines colliding with each other.

[0005] In addition, if the faulty (servo) engine and the opposite engine are shut down through a multi-engine launch vehicle, the thrust of both engines will be reduced at the same time, increasing the gravity loss of the rocket, which may directly lead to mission failure in severe cases.

[0006] In view of this, it is necessary to provide a new technical solution to solve the above problems. Summary of the invention

[0007] In order to solve the above technical problems, the present application provides a method for reconstructing the control of the servo mechanism failure of a multi-parallel engine launch vehicle, which can solve the problem of servo mechanism failure of a multi-parallel engine launch vehicle, complete control reconstruction without shutting down the engine, and avoid collision between engines.

[0008] A fault control reconstruction method for a multi-engine parallel launch vehicle servo mechanism includes:

[0009] The structural envelope of a single rocket engine is abstracted as a cone;

[0010] Based on the simplified cone, the swing angle of each engine that can be swung in the event of a servo mechanism failure is calculated;

[0011] The set of constraint relations between any two adjacent engines is used as the constraint relation of all engine swing angles;

[0012] The parallel engines are controlled according to the constraint relationship of the swing angles of all engines.

[0013] Preferably, the structural envelope of a single rocket engine is abstracted as a cone, including:

[0014] The axis of the rocket engine's swing shaft is used as the vertex of the cone; the tail envelope surface of the rocket engine's nozzle is used as the bottom surface of the cone; the bottom surface and the vertex of the cone are connected to form the side surface of the cone, and the structural envelope of a single rocket engine is abstracted as a cone.

[0015] Preferably, the swing angle of each engine that can swing in the event of a servo mechanism failure is:

[0016] ;

[0017] In the formula, is the swing angle of each engine in case of servo mechanism failure; The engine servo mechanism is stuck at an angle; The total swing angle required by the control system for all engines; is the number of engines connected in parallel on the launch vehicle; It is the ratio of the maximum swing angle that the engine can provide after the servo mechanism failure occurs to the maximum swing angle that the engine can provide before the servo mechanism failure occurs; is the ratio between the available swing angle of the engine and the maximum swing angle; The number of oscillating engines whose oscillation angle is affected; For the Engines; For the The ratio between the available swing angle and the maximum swing angle of an engine; The number of motors that are stuck in the servo mechanism.

[0018] Preferably, the expression for the ratio of the maximum swing angle that the engine can provide after the servo mechanism fails to the maximum swing angle that the engine can provide before the failure is:

[0019] ;

[0020] In the formula, is the sum of the swing angles of each engine that can be swung after a fault occurs; is the maximum swing angle and that all engines can provide before failure occurs.

[0021] Preferably, the calculation formula for the sum of the swing angles of each engine that can swing after the failure occurs is:

[0022] ;

[0023] Where: is the maximum swing angle of each engine; is the i-th engine; is the ratio between the available swing angle and the maximum swing angle of the i-th engine.

[0024] Preferably, the calculation formula for the ratio between the available swing angle and the maximum swing angle of the i-th engine is:

[0025] ;

[0026] Where: It is the available angle for the engine without servo jam to swing toward the engine with servo jam.

[0027] Preferably, the calculation formula for the available angle of the engine where the servo mechanism is not stuck to swing toward the side of the engine where the servo mechanism is stuck is:

[0028] ;

[0029] In the formula, It is the vertex angle of the enveloping triangle formed by the interference point and the vertical section where the engine axis is located; The base of the triangle formed by the engine with servo mechanism failure and its adjacent engine that can swing normally in the interference state; and It is the side of the enclosed triangle formed by the engine with servo mechanism failure and its adjacent normal swinging engine in the interference state.

[0030] Preferably, the expression of the maximum swing angle and that can be provided by all engines before the failure occurs is:

[0031] .

[0032] Preferably, when the launch vehicle servo mechanism is in normal working state, the expression of the swing angle required by each engine is:

[0033] .

[0034] Compared with the prior art, this application has at least the following beneficial effects:

[0035] The present invention can achieve the effect of completing control reconstruction and avoiding collision between engines without shutting down the engines when a servo mechanism of a multi-engine parallel-connected launch vehicle fails. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0037] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0038] Figure 2 Schematic diagram of multiple parallel connection of a certain type of multiple parallel connection launch vehicle engines in an embodiment of the present invention;

[0039] Figure 3 It is a parallel arrangement diagram of multiple parallel rocket engines in an embodiment of the present invention;

[0040] Figure 4 It is a schematic diagram of the arrangement of multiple parallel rocket engines in an embodiment of the present invention;

[0041] Figure 5 : is a diagram showing the relationship between the swing angle and position of engine No. 1 and its adjacent engine in an embodiment of the present invention;

[0042] Figure 6 Schematic diagram of the plane triangular envelope of a single engine simplified as a cone model in an embodiment of the present invention; wherein: Figure 6 (a) is a schematic diagram of the plane triangular envelope of a single engine and the position relationship of the engine; Figure 6 (b) is a schematic diagram of the plane triangular envelope of a single engine;

[0043] Figure 7 It is a schematic diagram of a plane triangular envelope of a parallel engine simplified as a cone model in an embodiment of the present invention;

[0044] Figure 8 A schematic diagram of the swing interference of parallel engines and its triangular envelope in an embodiment of the present invention;

[0045] Fig. 9 : is a diagram showing the relationship between the swing interference constraints and the enclosed triangles of adjacent engines in an embodiment of the present invention; wherein: Fig. 9 (a) is the adjacent engine swing interference constraint relationship diagram; Fig. 9 (b) is a schematic diagram of the enclosed triangle formed by adjacent engines. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0047] like Figure 1 As shown, a method for fault control reconstruction of a servo mechanism of a multi-engine parallel launch vehicle comprises the following steps:

[0048] Step S1, abstracting the structural envelope of a single rocket engine into a cone;

[0049] Step S2, based on the simplified cone, calculating the swing angle of each engine that can swing in the event of a servo mechanism failure;

[0050] Step S3, taking the set of constraint relations between any two adjacent engines as the constraint relations of all engine swing angles;

[0051] Step S4: Control the parallel engines according to the constraint relationship of the swing angles of all engines

[0052] In this embodiment, a certain type of multi-engine parallel launch vehicle is taken as an example, wherein one engine is arranged at the center of the rocket, and the remaining eight engines are distributed in a circumferential direction around the engine at the center, such as Figure 2 shown.

[0053] Each engine has two sets of servo mechanisms installed at a 90-degree angle on both sides of the engine, which can control the bidirectional swing of the liquid rocket engine. By swinging the engine, the thrust direction is changed, thereby generating a control torque to control the flight of the rocket. Under normal operation, the servo mechanisms of multiple parallel engines operate in the same way, that is, each engine swings according to a unified control instruction, and the swing angle and direction are the same when controlling the pitch and yaw channels of the launch vehicle. When controlling the rolling channel, except for the central engine, the swing angle is the same and the direction is connected. In this way, even if the engines are densely arranged, no collision will occur during flight.

[0054] The multiple engines of a multi-engine launch vehicle are fixed on a plane at the bottom of the rocket, such as Figure 3 The parallel arrangement of the engines can be made by Figure 3 get Figure 4, the positions of the 9 engines are represented by circles, numbered from 1 to 9, namely engine 1 to engine 9. The swing direction of the engine can be divided into two directions according to the rectangular coordinates. The engine servo mechanism is actuated so that the angle of the engine swing can be decomposed into these two directions. The swing direction of the engine is defined in two directions according to the attitude angle of the launch vehicle, namely pitch φ and yaw ψ. Similarly, the position / angle relationship between any two adjacent liquid engines can be as follows Figure 5 As shown, the positions / angles of engines 1 to 2, 8, and 9 can be decomposed into two directions: pitch φ and yaw ψ. Then, for the structural interference constraints considering different swing angles of the engines, only the angle constraint relationship between two adjacent liquid engines needs to be considered. The set of constraint relationships between any two adjacent liquid engines becomes the constraint relationship of all engine swing angles.

[0055] like Figure 6 As shown in the figure, the structural envelope of a single rocket engine can be abstracted as a cone. The interference point and the vertical section where the engine axis is located form an isosceles envelope triangle. The two base angles are the edges of the engine nozzle, and the vertex angle is It is the angle between the edge of the engine nozzle and the center of the engine swing shaft.

[0056] The shape of the engine is represented by an enveloping triangle. The side view of the arrangement of three engines in a nine-engine parallel rocket engine can be expressed as Figure 7 When the engine swings at different angles, interference occurs as shown in Figure 8 As shown in the figure, the enveloping triangles are in contact, and the base angle of the enveloping triangle of one engine touches the side of the enveloping triangle of another engine. When the two engines cause structural interference, the swing angles of the other engines are also constrained. Then, the swing angle relationship between any two adjacent liquid engines can be expressed as follows: Fig. 9 shown.

[0057] like Fig. 9 As shown in the figure, assuming that the servo mechanism of the left engine is stuck, the right engine swings to the left until structural interference occurs. At this time, the envelope triangle of the two engines and the connecting line of their vertices can form an enclosed triangle. At this time:

[0058] ;

[0059] ;

[0060] in, It is the bottom angle of the enclosed triangle where the servo mechanism is stuck on one side due to a fault; It is the included angle of the base of the enclosed triangle on the side where the servo mechanism is not stuck; It is the angle between the edge of the engine nozzle and the center of the engine swing shaft; The engine servo mechanism is stuck at an angle; is the available angle for the right engine to swing to the left. It should be noted that, for the convenience of calculation, the above expression is used as a fixed form. In this case, the engine may have a situation where the servo mechanism in this embodiment is stuck on the left side of the axis when the engine nozzle is in a vertical state, or a situation where a servo mechanism different from this embodiment is stuck on the right side of the axis when the engine nozzle is in a vertical state. Therefore, and It can be a positive value or a negative value. It should be noted that the engine with servo mechanism failure and its adjacent engine that can swing normally form an enclosed triangle in the interference state.

[0061] Let the three sides of the enclosing triangle be , , .in is the distance between the two engine swing shaft centers, which is a known quantity. and is the distance from the edge of the engine nozzle to the center of the engine swing shaft, and one of them is also a known quantity. It can be deduced that:

[0062] ;

[0063] ;

[0064] ;

[0065] Since we know the engine servo mechanism stuck angle , then we can infer:

[0066] ;

[0067] That is, when the servo mechanism of a certain engine is stuck at a certain angle, the available angle of the other engine to swing towards it is obtained:

[0068] ;

[0069] When the launch vehicle servo mechanism is in normal working state, the total swing angle required by the control system for all engines is , so that the launch vehicle is connected in parallel If there are 1000 engines, the required swing angle for each engine is:

[0070] ;

[0071] The maximum swing angle of each engine is , then the maximum swing angle that all engines can provide is:

[0072] ;

[0073] Now there is The servo mechanism of the engine is stuck and affects The maximum swing angle that all engines can provide is:

[0074] ;

[0075] in, is the ratio between the available swing angle and the maximum swing angle of the i-th engine:

[0076] ;

[0077] Thus, the ratio of the maximum swing angle that the engine can provide after the servo mechanism fails to that before the failure can be obtained. for:

[0078] ;

[0079] Then the swing angle of each engine in the case of servo failure can be obtained as:

[0080] ;

[0081] According to the swing angle of each engine in the case of servo mechanism failure, the constraint relationship between any two adjacent engines is obtained. The set of constraint relationships between any two adjacent engines is used as the constraint relationship of all engine swing angles, and it can be used to control parallel engines, that is, the control reconstruction of the servo mechanism failure of multi-engine parallel engine launch vehicle is realized.

[0082] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0083] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fault control reconstruction method for a multi-engine launch vehicle servo mechanism, characterized in that: include: The structural envelope of a single rocket engine is abstracted as a cone; Based on the simplified cone, the swing angle of each engine that can be swung in the event of a servo mechanism failure is calculated; The set of constraint relations between any two adjacent engines is used as the constraint relation of all engine swing angles; Controlling the parallel engines according to the constraint relationship of the swing angles of all engines; Among them, for the structural interference constraints considering different swing angles of the engine, the angle constraint relationship between two adjacent liquid engines is considered, and the set of constraint relationships between any two adjacent liquid engines becomes the constraint relationship of all engine swing angles; The swing angles of the engines that can swing when the servo mechanism fails are: ； In the formula, is the swing angle of each engine in case of servo mechanism failure; The engine servo mechanism is stuck at an angle; The total swing angle required by the control system for all engines; is the number of engines connected in parallel on the launch vehicle; It is the ratio of the maximum swing angle that the engine can provide after the servo mechanism failure occurs to the maximum swing angle that the engine can provide before the servo mechanism failure occurs; is the ratio between the available swing angle of the engine and the maximum swing angle; The number of oscillating engines whose oscillation angle is affected; For the Engines; For the The ratio between the available swing angle and the maximum swing angle of an engine; The number of motors that are stuck in the servo mechanism.

2. The method for fault control reconstruction of a multi-engine parallel-engine launch vehicle servo mechanism as claimed in claim 1, characterized in that: The structural envelope of a single rocket engine is abstracted as a cone, including: The axis of the rocket engine's swing shaft is used as the vertex of the cone; the tail envelope surface of the rocket engine's nozzle is used as the bottom surface of the cone; the bottom surface and the vertex of the cone are connected to form the side surface of the cone, and the structural envelope of a single rocket engine is abstracted as a cone.

3. The method for fault control reconstruction of a multi-engine parallel-engine launch vehicle servo mechanism as claimed in claim 1, characterized in that: The expression for the ratio of the maximum swing angle that the engine can provide after the servo mechanism fails to the maximum swing angle that the engine can provide before the failure is: ； In the formula, is the sum of the swing angles of each engine that can be swung after a fault occurs; is the maximum swing angle and that all engines can provide before failure occurs.

4. The method for fault control reconstruction of a multi-engine parallel-engine launch vehicle servo mechanism as claimed in claim 3, characterized in that: The calculation formula for the sum of the swing angles of each engine that can swing after the fault occurs is: ； Where: is the maximum swing angle of each engine; is the i-th engine; is the ratio between the available swing angle and the maximum swing angle of the i-th engine.

5. The method for fault control reconstruction of a multi-engine parallel-engine launch vehicle servo mechanism as claimed in claim 4, characterized in that: The calculation formula for the ratio between the available swing angle and the maximum swing angle of the i-th engine is: ； Where: It is the available angle for the engine without servo jam to swing toward the engine with servo jam.

6. The method for fault control reconstruction of a multi-engine parallel-engine launch vehicle servo mechanism as claimed in claim 5, characterized in that: The calculation formula for the available angle of the engine that has not had its servo mechanism stuck to swing toward the side of the engine that has had its servo mechanism stuck is: ； In the formula, It is the vertex angle of the enveloping triangle formed by the interference point and the vertical section where the engine axis is located; The base of the triangle formed by the engine with servo mechanism failure and its adjacent engine that can swing normally in the interference state; and It is the side of the enclosed triangle formed by the engine with servo mechanism failure and its adjacent normal swinging engine in the interference state.

7. The method for fault control reconstruction of a multi-engine parallel-engine launch vehicle servo mechanism as claimed in claim 6, characterized in that: The maximum swing angle and value that all engines can provide before the failure occurs is expressed as: 。 8. The method for fault control reconstruction of a multi-engine parallel-engine launch vehicle servo mechanism as claimed in claim 7, characterized in that: When the launch vehicle servo mechanism is in normal working state, the expression of the swing angle required by each engine is: 。

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