Carrier rocket grid rudder control method based on dynamic pressure

Abstract

The invention discloses a dynamic pressure-based carrier rocket grid rudder control method, which comprises the following steps of: according to a pre-launch binding wind field and the speed of a carrier rocket at the current moment, calculating to obtain the relative airflow speed of the carrier rocket at the current moment; according to the current relative airflow velocity of the carrier rocket, calculating to obtain a current dynamic pressure estimated value; according to the dynamic pressure estimation value at the current moment, solving a control law parameter in the grid rudder online variable gain control law to obtain an optimal control law parameter at the current moment; according to the optimal control law parameters at the current moment, a grid rudder swing angle control instruction at the current moment is obtained through calculation, and real-time control over the grid rudder of the carrier rocket is completed. The method can effectively adapt to the rapid change pneumatic environment of the reentry flight section, remarkably reduces the flight deviation, is suitable for various carrier rocket reentry recovery scenes, and has the advantages of being high in engineering practicability, high in control efficiency and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of launch vehicle attitude control, and particularly relates to a launch vehicle grid fin control method based on dynamic pressure. BACKGROUND

[0002] During the return flight of a launch vehicle, attitude adjustment and trajectory correction need to be achieved through grid fins. As an important aerodynamic control device, the control effect of the grid fin directly affects the flight stability, control accuracy and recovery success rate of the rocket. At present, most launch vehicle control strategies are based on fixed parameters and pre-installed control parameter matrices that change with time. These methods usually assume that the control ability of the rocket body changes slowly or remains unchanged over time. However, during the reentry flight of a return rocket, the dynamic pressure changes dramatically with the rocket height, speed and atmospheric density, and the grid fin effectiveness also changes dramatically. The traditional control method cannot respond to the change in dynamic pressure in real time, resulting in a mismatch between the control command and the actual grid fin effectiveness, and further causing problems such as attitude oscillation, control lag or over-adjustment. SUMMARY

[0003] The technical problem of the present application is to overcome the shortcomings of the prior art and provide a launch vehicle grid fin control method based on dynamic pressure, which aims to overcome the shortcomings of traditional launch vehicle control strategies that cannot adapt to the dramatic changes in grid fin effectiveness with the environment, solve the problem of grid fin control during rocket reentry flight, and be applicable to the control of return rockets during reentry flight.

[0004] To solve the above technical problems, the present application discloses a launch vehicle grid fin control method based on dynamic pressure, comprising: According to the pre-launch wind field and the current speed of the launch vehicle, the relative airflow speed of the launch vehicle at the current time is calculated; According to the relative airflow speed of the launch vehicle at the current time, the dynamic pressure estimation value at the current time is calculated; According to the dynamic pressure estimation value at the current time, the control law parameters in the online variable gain control law of the grid fin are solved to obtain the optimal control law parameters at the current time; According to the optimal control law parameters at the current time, the grid fin angle control command at the current time is calculated to complete the real-time control of the launch vehicle grid fin.

[0005] In the above launch vehicle grid fin control method based on dynamic pressure, according to the pre-launch wind field and the current speed of the launch vehicle, the relative airflow speed of the launch vehicle at the current time is calculated, comprising: According to the pre-launch wind field and the current flight altitude, the current wind speed is interpolated And the wind direction angle ; According to And , to obtain the current time navigation system wind speed :

[0006] wherein, represents the launch azimuth angle; represents the current time; According to and the current time navigation system speed of the launch vehicle , the current time navigation system relative airflow speed of the launch vehicle is calculated : .

[0007] In the above launch vehicle grid fin control method based on dynamic pressure, the current time dynamic pressure estimation value is calculated according to the current time relative airflow speed of the launch vehicle, including: According to the current time flight altitude of the launch vehicle , combined with the atmospheric density interpolation table, the current time atmospheric density is calculated by interpolation; According to and , the current time dynamic pressure estimation value is calculated: .

[0008] In the above launch vehicle grid fin control method based on dynamic pressure, the current time optimal control law parameter is obtained by solving the control law parameter in the online variable gain control law of the grid fin according to the current time dynamic pressure estimation value, including: The online variable gain control law of the grid fin is constructed:

[0009] wherein, represents the current time rudder efficiency coefficient, represents the first exponential coefficient, represents the second exponential coefficient; According to the current time nominal dynamic pressure and the current time static total gain , the current time static total gain residual is determined:

[0010] wherein, represents the maximum value of the static total gain; The constraint condition is determined:

[0011] According to the above constraint condition, the current time optimal control law parameter is calculated: , and ; wherein, , and represent the optimal solutions of , and , respectively.

[0012] In the above grid fin control method based on dynamic pressure, the grid fin swing angle control command at the current time is calculated according to the optimal control law parameters at the current time, and real-time control of the grid fin of the launch vehicle is completed, including: According to , and , combined with the attitude angle deviation and the attitude angle rate deviation at the current time, the channel command at the current time is calculated:

[0013] wherein, , and represent the pitch channel command, the yaw channel command and the roll channel command at the current time, represents the total dynamic gain at the current time; , and represent the pitch, yaw and roll channel attitude angle deviations at the current time; , and represent the pitch, yaw and roll channel attitude angle rate deviations at the current time; Take , and as the input of the correction network, and the output values after the correction network are: , and ; According to , and , swing angle distribution is performed to obtain the grid fin swing angle control command at the current time:

[0014] wherein, represents the grid fin distribution matrix.

[0015] In the above grid fin control method based on dynamic pressure, the grid fin swing angle control command at the current time is calculated according to the optimal control law parameters at the current time, and real-time control of the grid fin of the launch vehicle is completed, further including: According to the current moment attitude angle and program angle, the current moment attitude angle deviation is calculated:

[0016] Among them, , And Respectively, the current moment pitch, yaw, roll channel attitude angle; , And Respectively, the current moment pitch, yaw, roll channel program angle; According to the current moment attitude angle rate and program angle rate, the current moment attitude angle rate deviation is calculated:

[0017] Among them, , And Respectively, the current moment pitch, yaw, roll channel attitude angle rate; , And Respectively, the current moment pitch, yaw, roll channel program angle rate.

[0018] The present application has the following advantages: (1) The present application discloses a kind of based on dynamic pressure's launch vehicle grid rudder control method, with dynamic pressure online real-time adjustment grid rudder online variable gain control law in control law parameter, different from traditional control law with time solidification gain mode, greatly improve the adaptability to the aerodynamic environment of reentry flight segment dramatic change, can guarantee the reentry flight stability of launch vehicle and control precision.

[0019] (2) The present application discloses a kind of based on dynamic pressure's launch vehicle grid rudder control method, by pre-launch wind field, obtain more accurate launch vehicle relative airflow velocity, improve the dynamic pressure estimation precision, improve the grid rudder gain and rudder effect matching degree.

[0020] (3) The present application discloses a kind of based on dynamic pressure's launch vehicle grid rudder control method, after launch vehicle return flight verification, result shows, grid rudder swing angle change is stable, the attitude of arrow body is stable, effect is good. DETAILED DESCRIPTION

[0021] Figure 1 It is the flow chart of a kind of based on dynamic pressure's launch vehicle grid rudder control method in the embodiment of the present application; Figure 2 It is a kind of grid rudder control principle schematic diagram in the embodiment of the present application. DETAILED DESCRIPTION

[0022] For the purposes of the present invention, the technical solutions and advantages will be more apparent in the following detailed description of the disclosed embodiments, with reference to the accompanying drawings.

[0023] Referring to Figure 1 In this embodiment, the grid fin control method for a launch vehicle based on dynamic pressure comprises the following steps: S1, according to the pre-launch wind field and the current speed of the launch vehicle, the current relative airflow speed of the launch vehicle is calculated.

[0024] In this embodiment, the current relative airflow speed of the launch vehicle can be calculated in the following way: According to the pre-launch wind field and the current flight altitude, the current wind speed is obtained by interpolation And the wind direction angle .

[0025] According to And , the current navigation system wind speed is obtained:

[0026] Wherein, represents the launch azimuth angle, which is a constant value; represents the current time.

[0027] According to And the current navigation system speed of the launch vehicle , the current navigation system relative airflow speed of the launch vehicle is calculated:

[0028] S2, according to the current relative airflow speed of the launch vehicle, the current dynamic pressure estimation value is calculated.

[0029] In this embodiment, the current dynamic pressure estimation value can be calculated in the following way: According to the current flight altitude of the launch vehicle , combined with the atmospheric density interpolation table, the current atmospheric density is calculated by interpolation. The atmospheric density interpolation table is shown in Table 1 as follows:

[0030] Table 1: Atmospheric density interpolation table Wherein, represents the air pressure height, ; represents the flight altitude; represents the short semi-axis of the earth; represents the sea level air density; represents the ratio of high-altitude temperature and sea level temperature.

[0031] Further, according to and , the current dynamic pressure estimation value is calculated:

[0032] S3, according to the current dynamic pressure estimation value, the control law parameters in the on-line variable gain control law of the grid fin are solved to obtain the optimal control law parameters at the current time.

[0033] In this embodiment, the optimal control law parameters at the current time can be solved in the following way: Construct the on-line variable gain control law of the grid fin:

[0034] wherein, represents the rudder efficiency coefficient at the current time, represents the first exponential coefficient, represents the second exponential coefficient.

[0035] According to the current nominal dynamic pressure and the current static total gain , the current static total gain residual is determined:

[0036] wherein, represents the maximum value of the static total gain.

[0037] The constraint condition is determined:

[0038] According to the above constraint condition, the optimal control law parameters at the current time are calculated: , and ; wherein, , and respectively represent the optimal solutions of , and .

[0039] S4, according to the optimal control law parameters at the current time, the current grid fin angle control command is solved to complete the real-time control of the grid fin of the launch vehicle.

[0040] In this embodiment, the grid fin control principle is as follows: Figure 2As shown, the current time grid rudder swing angle control instruction can be calculated to complete real-time control of the grid rudder of the carrier rocket in the following manner: According to the current time attitude angle and the program angle, the current time attitude angle deviation is calculated:

[0041] Among them, , and respectively represent the current time pitch, yaw, and roll channel attitude angle deviation; , and respectively represent the current time pitch, yaw, and roll channel attitude angle; , and respectively represent the current time pitch, yaw, and roll channel program angle.

[0042] According to the current time attitude angle rate and the program angle rate, the current time attitude angle rate deviation is calculated:

[0043] Among them, , and respectively represent the current time pitch, yaw, and roll channel attitude angle rate deviation; , and respectively represent the current time pitch, yaw, and roll channel attitude angle rate; , and respectively represent the current time pitch, yaw, and roll channel program angle rate.

[0044] According to , and , combined with the current time attitude angle deviation and the attitude angle rate deviation, the current time channel instruction is calculated:

[0045] Among them, , and respectively represent the current time pitch channel instruction, yaw channel instruction, and roll channel instruction, represents the current time dynamic total gain. It should be noted that suitable and can be designed according to the nominal sequence of the grid rudder control torque coefficient and the control bandwidth requirement of the rocket body.

[0046] The 、 and As the input of the correction network, the output value after the correction network is respectively: 、 and .

[0047] According to 、 and , the swing angle distribution is carried out to obtain the current time grid rudder swing angle control instruction :

[0048] Wherein, The grid rudder distribution matrix is represented.

[0049] To sum up, the application discloses a kind of based on dynamic pressure's launch vehicle grid rudder control method, by constructing with dynamic pressure as input, control gain as output grid rudder online variable gain control law, for grid rudder control proposes a new solution idea;The launch vehicle grid rudder control method based on dynamic pressure, after launch vehicle returns and flies, pure grid rudder control section, rocket body posture is stable, control quality is good, can satisfy return type launch vehicle reentry flight control.

[0050] Although the present application has been disclosed as above with preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application by using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, which does not deviate from the technical solutions of the present application, shall fall within the protection scope of the present application.

[0051] The contents not described in detail in the specification of the present application belong to the known technology of those skilled in the art.

Claims

1. A launch vehicle grid fin control method based on dynamic pressure, characterized in that, The method comprises the following steps: According to the pre-launch wind field and the current speed of the carrier rocket, the relative airflow speed of the carrier rocket at the current time is calculated; According to the current relative airflow speed of the carrier rocket, the current dynamic pressure estimation value is calculated; According to the current dynamic pressure estimation value, the control law parameters in the online variable gain control law of the grid fin are solved to obtain the optimal control law parameters at the current time; According to the optimal control law parameters at the current time, the current grid fin swing angle control instruction is solved to complete the real-time control of the grid fin of the carrier rocket.

2. The method of claim 1, wherein, According to the pre-launch wind field and the current speed of the carrier rocket, the relative airflow speed of the carrier rocket at the current time is calculated, comprising: According to the pre-flight binding wind field and the current flight height, the current wind speed is obtained by interpolation and the wind direction angle ; According to and , the current time navigation system wind speed is obtained: wherein denotes the transmit azimuth angle; denotes the current time instant; According to and the current time navigation system velocity of the launch vehicle , the current time navigation system relative airflow velocity of the launch vehicle is calculated : 。 3. The method of claim 2, wherein, According to the current relative airflow speed of the carrier rocket, the current dynamic pressure estimation value is calculated, comprising: According to the current flight height of the carrier rocket , in combination with an atmospheric density interpolation table, the current atmospheric density is calculated by interpolation ; According to and , the current dynamic pressure estimate is calculated: 。 4. The method of claim 3, wherein, According to the current dynamic pressure estimation value, the control law parameters in the online variable gain control law of the grid fin are solved to obtain the optimal control law parameters at the current time, comprising: Constructing the online variable gain control law of the grid fin: wherein, represents the rudder effectiveness coefficient at the current time point, represents the first exponential coefficient, represents the second exponential coefficient; determined based on the current time nominal dynamic pressure and the current time static total gain , a current time static total gain residual is determined wherein denotes the static total gain maximum value; Determining the constraint condition: According to the above constraint conditions, the optimal control law parameters at the current time are calculated as: , and ; wherein, , and represent the optimal solutions of , and , respectively.

5. The method of claim 4, wherein, According to the optimal control law parameters at the current time, the current grid fin swing angle control instruction is solved to complete the real-time control of the grid fin of the carrier rocket, comprising: According to , and , the channel command at the current moment is calculated by combining the attitude angle deviation and the attitude angle rate deviation at the current moment: wherein, , and represent the current time instant pitch, yaw and roll channel commands, respectively, represents the current time instant dynamic total gain; , and represent the current time instant pitch, yaw and roll channel attitude angle errors, respectively; , and represent the current time instant pitch, yaw and roll channel attitude angular rate errors, respectively; Will , and As input to the calibration network, the output values ​​after calibration are as follows: , and ; According to , and , the rudder swing angle distribution is performed to obtain the current time grid rudder swing angle control instruction : wherein, represents the lattice steering distribution matrix.

6. The method of claim 5, wherein, According to the optimal control law parameters at the current time, the current grid fin swing angle control instruction is solved to complete the real-time control of the grid fin of the carrier rocket, further comprising: According to the current attitude angle and the program angle, the current attitude angle deviation is calculated: wherein, , and represent the current time pitch, yaw, roll channel attitude angle, respectively; , and represent the current time pitch, yaw, roll channel program angle, respectively; According to the current attitude angular rate and the program angular rate, the current attitude angular rate deviation is calculated: wherein, , and represent the current time pitch, yaw, roll channel attitude angular rate, respectively; , and represent the current time pitch, yaw, roll channel program angular rate, respectively.

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