An upper stage attitude control method based on average periodic control force

Abstract

The present invention provides an upper stage attitude control method based on average period control force, comprising: S1: two roll attitude control nozzles and two deflection attitude control nozzles are arranged on the same upper stage of the rocket head; S2: two roll attitude control nozzles are started to control the rocket to rotate forward or reverse and maintain a constant roll angular velocity; S3: the pitch control torque and yaw control torque required for the two deflection attitude control nozzles to adjust the rocket to a standard attitude within the average period, as well as the pitch working angle θ and the yaw working angle σ; S4: then according to the pitch working angle θ and the yaw working angle σ, the two deflection attitude control nozzles are started and closed to correct the attitude of the rocket head. The present invention solves the problem of excessive control torque for solving interference torque in the prior art, can effectively reduce the complexity of the attitude control structure system, solve the interference torque caused by engine thrust deflection, thrust lateral displacement and structural deviation, and enhance the stability of the rocket.

Description

Technical Field

[0001] The invention relates to the technical field of rocket attitude control, and in particular to an upper stage attitude control method based on average periodic control force. Background Art

[0002] The upper stage is generally a relatively independent stage (or multiple stages) added to the basic stage launch vehicle. It has strong mission adaptability and can complete tasks such as orbital maneuvers and payload separation. It is an effective way to improve rocket performance and mission adaptability. The attitude control system is a component of the upper stage control system. Its task is to overcome various interferences during the flight of the upper stage and stabilize and control the attitude movement of the upper stage. The attitude control of the upper stage includes two aspects: attitude stabilization and attitude maneuverability. The former is the process of maintaining the existing attitude, and the latter is the redirection process of changing the upper stage from one attitude to another.

[0003] At present, the attitude control of the upper stage of the launch vehicle is three-axis stable control, and its actuators all use more than 8 attitude control nozzles. Since the structure of the rocket is not symmetrical during the processing, it is easy to cause deviations such as mass eccentricity and thrust eccentricity. As a result, the attitude control system structure is complex and requires a very large control torque to solve the interference torque caused by the engine's thrust deviation, thrust lateral shift and structural deviation. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an upper stage attitude control method based on average periodic control force, which solves the problem of excessive control torque in solving the interference torque in the prior art, can effectively reduce the complexity of the attitude control structure system, solve the interference torque caused by engine thrust deviation, thrust lateral shift and structural deviation, and enhance the stability of the rocket.

[0005] According to an embodiment of the present invention, an upper stage attitude control method based on average periodic control force includes:

[0006] S1: Two roll attitude control nozzles and two yaw attitude control nozzles are arranged on the same upper stage of the rocket head. The two roll attitude control nozzles are used to control the roll of the rocket together, and the two yaw attitude control nozzles are used to control the pitch and yaw of the rocket respectively.

[0007] S2: Start two roll attitude control nozzles to control the rocket to rotate forward or reverse and maintain a constant roll angular velocity;

[0008] S3: According to the angular deviations between the pitch and yaw attitudes of the current rocket and the standard attitude, the pitch control torque and yaw control torque required by the two deflection attitude control nozzles to adjust the rocket to the standard attitude within the average period, as well as the pitch working angle θ and yaw working angle σ of the two deflection attitude control nozzles rotating with the rocket in the working state are calculated respectively;

[0009] S4: According to the pitch working angle θ and the yaw working angle σ, start and close the two deflection attitude control nozzles to correct the attitude of the rocket head.

[0010] Preferably, the thrust directions of the two roll attitude control nozzles are opposite and are both along the outer diameter direction of the upper stage, and the thrust directions of the two deflection attitude control nozzles are perpendicular to each other and are both along the radial direction of the upper stage.

[0011] Preferably, the constant value of the rolling angular velocity in S2 is 340° / s.

[0012] Preferably, in said S3, within one rolling cycle,

[0013] If the pitch control torque is positive, the range of the pitch working angle θ is

[0014] If the pitch control torque is negative, the range of the pitch working angle θ is

[0015] If the yaw control torque is positive, the range of the yaw working angle σ is

[0016] If the yaw control torque is negative, the range of the yaw working angle σ is

[0017] Preferably, in S4, if the value of θ or |σ| is greater than 7°, posture correction is performed, otherwise no correction is performed.

[0018] Preferably, the roll attitude control nozzle and the yaw attitude control nozzle mainly work when the rocket is in a thin atmosphere or outside the atmosphere, so the influence of external flight environment such as the atmosphere can be ignored.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] Using two rolling attitude control nozzles to make the rocket rotate around its own axis can effectively reduce the negative impact of structural asymmetry and deviations such as mass eccentricity and thrust eccentricity generated during the processing on control, while enhancing stability; in addition, the method of calculating control force and torque by averaging the period only requires controlling two deflection attitude control nozzles to correct the pitch and yaw angles respectively, which can reduce the number of attitude control nozzles and reduce the complexity of the upper stage attitude control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a layout diagram of the attitude control nozzle according to an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the roll attitude control nozzle controlling the roll of the upper stage according to an embodiment of the present invention.

[0023] Figure 3 Schematic diagram of pitch control according to an embodiment of the present invention.

[0024] Figure 4 Schematic diagram of yaw control according to an embodiment of the present invention.

[0025] Figure 5 is a roll angular velocity response curve of an embodiment of the present invention.

[0026] Figure 6 FIG. 4 is a curve showing a roll angle variation with time according to an embodiment of the present invention.

[0027] Figure 7 1 is a pitch angle instruction and a tracking curve according to an embodiment of the present invention.

[0028] Figure 8 FIG. 4 is a curve showing the change of the required θ angle over time according to an embodiment of the present invention.

[0029] Fig. 9 yaw angle command and tracking curve according to an embodiment of the present invention.

[0030] Fig.10 FIG. 4 is a curve showing the change of the required σ angle with time according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0032] like Figure 1 As shown, the embodiment of the present invention proposes an upper stage attitude control method based on average periodic control force, two roll attitude control nozzles and two deflection attitude control nozzles are installed on the edge of a certain plane of the rocket head (i.e., the upper stage), the attitude control nozzles spray working fluid to the outside of the rocket, and the direction of the reaction force points to the inside of the aircraft. Since the roll attitude control nozzles and the deflection attitude control nozzles mainly work when the rocket is in a thin atmosphere or outside the atmosphere, the influence of the external flight environment such as the atmosphere can be ignored, wherein the thrust action lines F1 and F2 of the two roll attitude control nozzles are along the tangent direction of the outer diameter of the attitude control installation plane, which are used to generate rolling moments in positive and negative directions to jointly control the roll of the rocket, and the thrust action lines F3 and F4 of the two deflection attitude control nozzles are perpendicular to each other and are along the radial direction of the upper stage, which are used to generate moments in pitch and yaw directions. In addition, the initial parameters of the rocket are set afterwards, as shown in Table 1, wherein L1 and L2 are the force arms during roll, Lc It is the force arm during pitch and yaw.

[0033] Table 1

[0034]

[0035] like Figure 2 As shown, the two roll attitude control nozzles spray along the tangent direction of the outer diameter of the attitude control installation plane, and the thrust action lines are F1 and F2 respectively, which control the rocket to rotate forward or reverse along its own axis and maintain the rotation angular velocity at 340° / s. By achieving a certain spin-stable roll angular velocity, its stability is enhanced, and the influence of the interference torque caused by thrust eccentricity is effectively solved through rotation, which reduces the R&D and manufacturing costs and the requirements for the manufacturing processability of the upper stage, while reducing the complexity of the upper stage attitude control system.

[0036] The roll angle value range for one cycle is -π~π, such as Figure 3 As shown, one of the deflection attitude control nozzles controls the pitch of the rocket upper stage, and its thrust action line is F3, and the direction of the resultant force is on the y-axis. According to the angular deviation between the pitch attitude of the rocket and the standard attitude, the pitch working angle θ of the automatic control nozzle that rolls with the rocket in the working state to adjust the rocket to the standard attitude is obtained. Therefore, the average value of the rocket in one rotation is:

[0037]

[0038] Therefore, the equivalent pitch control force and moment after one rotation can be calculated as:

[0039]

[0040] In the formula,

[0041] F3--Instantaneous control force of attitude control nozzle that controls the pitch state of rocket;

[0042] F y --Equivalent pitch control force of one rocket rotation;

[0043] L c --The distance from the attitude control nozzle plane to the center of mass;

[0044] M z --Equivalent pitch control torque per rotation.

[0045] In addition, if the pitch control torque is positive, the range of the pitch working angle θ is

[0046] If the pitch control torque is negative, the range of the pitch working angle θ is

[0047] It can be seen that the pitch attitude of the rocket can be controlled by adjusting the size of the θ value and the time of the initial value of θ in each cycle.

[0048] Similarly, if Figure 4 As shown in the figure, one of the deflection attitude control nozzles controls the yaw of the rocket upper stage, and its thrust action line is F4. The direction of the resultant force is on the z-axis. According to the angular deviation between the pitch attitude of the rocket and the standard attitude, the pitch working angle σ of the automatic control nozzle that rolls with the rocket in the working state to adjust the rocket to the standard attitude is obtained. Therefore, the average value of the rocket in one rotation is:

[0049]

[0050] Therefore, the equivalent yaw control force and torque after one rotation can be calculated as:

[0051]

[0052] Where:

[0053] F4--Instantaneous control force of attitude control nozzle that controls the yaw state of the rocket;

[0054] F z --Equivalent yaw control force for one rotation;

[0055] L c --The distance from the attitude control nozzle plane to the center of mass;

[0056] M y --Equivalent yaw control torque per rotation.

[0057] In addition, if the yaw control torque is positive, the range of the yaw working angle σ is

[0058] If the yaw control torque is negative, the range of the yaw working angle σ is

[0059] It can be seen that the rocket's yaw attitude can be controlled by adjusting the size of the σ value and the time of the initial value of σ in each cycle.

[0060] In addition, if the value of |θ| or |σ| is greater than 7°, the posture correction in the corresponding direction will be performed, otherwise no correction will be performed.

[0061] In summary, since the roll attitude control nozzle and the yaw attitude control nozzle mainly work when the rocket is in a thin atmosphere or outside the atmosphere, the influence of the external flight environment such as the atmosphere can be ignored, and the rocket is controlled by three channels according to the following upper stage dynamics model to correct its flight attitude. The control results are as follows Figures 5 to 10 As shown:

[0062]

[0063]

[0064] ψ, γ are pitch angle, yaw angle and roll angle respectively; ω z1 ,ω y1 ,ω x1 are pitch, yaw and roll angular velocities respectively; J x , J y , J z is the moment of inertia; M x1 、M y1 、M x1 Three-channel control torque

[0065] The rolling moment generated by F2 is:

[0066] M x1 =F2L2

[0067] The average control moment of pitch generated by F3 is:

[0068]

[0069] The average control torque of yaw generated by F4 is:

[0070]

[0071] Depend on Figure 5 and Figure 6 It can be seen that the roll angular velocity is stable in the area behind the rapid response and no longer changes. At this time, the change of the roll angle is also linear within a cycle, indicating that the roll stability is strong, which can effectively reduce the negative impact of the structural asymmetry, mass eccentricity, thrust eccentricity and other deviations on the control caused by the processing process. Figure 7 and Fig. 9 It can be seen that during the actual operation of the rocket, its pitch angle and yaw angle always float near the pitch angle command and yaw angle command curves respectively, so that θ and σ also float slightly on the 0 degree line. Compared with the existing 8-nozzle control, it not only reduces the number of attitude control nozzles and the complexity of the upper stage attitude control system, but also has higher stability.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. An upper stage attitude control method based on average periodic control force, characterized in that: include: S1: Two roll attitude control nozzles and two yaw attitude control nozzles are arranged on the same upper stage of the rocket head. The two roll attitude control nozzles are used to control the roll of the rocket together, and the two yaw attitude control nozzles are used to control the pitch and yaw of the rocket respectively. The thrust directions of the two roll attitude control nozzles are opposite and are both along the outer diameter direction of the upper stage. The thrust directions of the two yaw attitude control nozzles are perpendicular to each other and are both along the radial direction of the upper stage. S2: Start two roll attitude control nozzles to control the rocket to rotate forward or reverse and maintain a constant roll angular velocity. The constant roll angular velocity in S2 is 340° / s. S3: According to the angular deviations between the pitch and yaw attitudes of the current rocket and the standard attitude, the pitch control torque and yaw control torque required by the two deflection attitude control nozzles to adjust the rocket to the standard attitude within the average period, as well as the pitch working angle θ and yaw working angle σ of the two deflection attitude control nozzles rotating with the rocket in the working state are calculated respectively; Among them, the pitch control force and moment values ​​for one rotation are: ； The yaw control force and moment values ​​for one rotation are: ； In the formula, To control the instantaneous control force of the attitude control nozzle to control the pitch state of the rocket; Provides pitch control force for one rotation of the rocket; is the distance from the attitude control nozzle plane to the center of mass; The pitch control torque for one rotation; To control the instantaneous control force of the attitude control nozzle to control the yaw state of the rocket; The yaw control force for one rotation; The yaw control torque for one rotation; In one rolling cycle, If the pitch control torque is positive, the range of the pitch working angle θ is: ； If the pitch control torque is negative, the range of the pitch working angle θ is: ； If the yaw control torque is positive, the range of the yaw working angle σ is: ； If the yaw control torque is negative, the range of the yaw working angle σ is: ； S4: According to the pitch working angle θ and the yaw working angle σ, start and close the two deflection attitude control nozzles to correct the attitude of the rocket head; or The attitude correction is performed only when the value of is greater than 7°, otherwise no correction is performed.

2. The upper stage attitude control method based on average periodic control force as claimed in claim 1, characterized in that: The roll attitude control nozzle and the yaw attitude control nozzle mainly work when the rocket is in a thin atmosphere or outside the atmosphere, so the influence of the flight environment outside the atmosphere is ignored.

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