Online efficient load shedding control method based on forecast wind field

Abstract

The invention discloses an online efficient load shedding control method based on a forecast wind field. The method comprises the following steps: firstly, acquiring a load attack angle and a sideslip angle which are calculated in real time on a rocket; amplitude limiting processing is carried out on the load attack angle and the sideslip angle, an attack angle control instruction is generated after gain control network calculation is carried out, and an attitude control system carries out direct attack angle control in a load sensitive area in combination with the load shedding requirement and the guidance deviation correction capacity; and pitching and yaw feedback control instructions are generated, active load shedding control is implemented, and errors generated by attack angle control are compensated. The on-line active and passive load shedding mode covers the real deviation or interference influence during flight, the generated load shedding instruction is better matched with the actual flight, the universality is good, the implementation is easy, and the load shedding effect is better.

Description

Technical Field

[0001] The invention relates to the field of launch vehicle control systems, in particular to an online high-efficiency load reduction control method based on predicted wind fields. Background Art

[0002] In the launch mission of a carrier rocket, in order to reduce the size of the wind attack angle during flight, the traditional method is to use pre-launch ballistic wind correction technology. The wind-corrected ballistic program angle is obtained offline based on the standard trajectory, and then bound to the arrow for flight to reduce the wind load during the flight. This is a feedforward open-loop control mode with poor load reduction control effect. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art, to provide an online efficient load reduction control method based on predicted wind fields, and to generate load reduction instructions that are better matched with actual flight.

[0004] The technical solution of the present invention is: an online high-efficiency load reduction control method based on wind field forecast, comprising:

[0005] Obtain the load attack angle and sideslip angle calculated in real time on the arrow;

[0006] After limiting the load angle of attack and sideslip angle and calculating the gain control network, the angle of attack control command is generated. The attitude control system combines the load reduction demand and the guidance and correction capability to implement direct angle of attack control in the load-sensitive area.

[0007] Generate pitch and yaw feedback control commands, implement active load reduction control, and compensate for errors caused by angle of attack control.

[0008] Furthermore, the load attack angle and sideslip angle are limited in the following way:

[0009] if but if but

[0010] if but if but

[0011] in, are the various parameters, is the load angle of attack and sideslip angle after limiting processing, α a is the load attack angle, β a is the sideslip angle.

[0012] Furthermore, the angle of attack control command The generation method is:

[0013]

[0014] in, is the gain parameter;

[0015] It is the angle of attack control network; is the discrete network numerator coefficient, is the discrete network sub-coefficient;

[0016] It is the side slip angle control network; is the discrete network numerator coefficient, is the discrete network mesh coefficient.

[0017] Furthermore, the pitch and yaw feedback control instructions L1 and L2 are calculated as follows:

[0018]

[0019] in, is the pitch angle deviation, Δψ C is the yaw angle deviation, is the gain parameter, and D ψ (z) are pitch and yaw network parameters, respectively, and They are the pitch and yaw guidance network parameters or the table feedback load shedding network parameters. Guidance and table feedback load shedding are used in different time periods. Table feedback load shedding is used in high wind areas, and guidance is used after passing through high wind areas. z and ω y are the pitch and yaw angular velocities, It is the angle of attack control command.

[0020] Furthermore, the load angle of attack and sideslip angle are calculated as:

[0021] During the flight, real-time wind field information, including wind speed and wind direction, is obtained according to the flight altitude of the carrier rocket, and the projection of the wind vector in the launch coordinate system is calculated. The carrier rocket body speed is obtained through the navigation information on the carrier rocket, and based on the carrier rocket body speed and the projection of the wind vector in the launch coordinate system, the launch coordinate system airspeed vector and airspeed magnitude are obtained, thereby obtaining the load angle of attack and sideslip angle.

[0022] Furthermore, the projection of the wind vector in the emission coordinate system is calculated as follows:

[0023]

[0024] In the formula, G E is the transformation matrix from the geocentric coordinate system to the launch coordinate system, E Tis the transformation matrix from the local horizontal coordinate system to the geocentric coordinate system, and They are the wind speed and wind direction interpolated according to the flight altitude of the launch vehicle;

[0025] The launch coordinate system airspeed vector is calculated as:

[0026]

[0027] In the formula, is the velocity of the launch vehicle obtained through the navigation information on the launch vehicle;

[0028] The airspeed is calculated as:

[0029]

[0030] Furthermore, the load attack angle and sideslip angle are calculated as follows:

[0031] Calculate the projection of the airspeed vector on the arrow system:

[0032]

[0033] In the formula, B G is the transformation matrix from the launch coordinate system to the rocket body coordinate system;

[0034] Calculate the load attack angle α a , sideslip angle β a :

[0035]

[0036] The present invention also provides a computer program product, which implements the steps of the method when executed by a processor.

[0037] The present invention also provides an arrow computing terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the steps of the method are implemented when the processor executes the computer program.

[0038] The advantages of the present invention compared with the prior art are:

[0039] According to the total angle of attack information solved in real time on the arrow, the attitude control system of the present invention combines the actual load reduction demand and the subsequent guidance and correction capability to implement direct angle of attack control in the load-sensitive area. On the other hand, there will be a deviation between the predicted wind field and the actual wind field. Active load reduction control is implemented by combining acceleration information to compensate for the error caused by the total angle of attack feedforward control. This online active and passive load reduction method covers the actual deviation or interference during flight, and the generated load reduction instructions are better matched with the actual flight. The method is versatile, easy to implement, and has a better load reduction effect. The present invention converts the traditional offline ballistic wind correction mode of the launch vehicle based on the wind field into a real-time ballistic correction mode in flight. It is an innovative, practical and effective engineering design method. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the main process of the present invention;

[0041] Figure 2 This is a comparison chart of the simulation results of the present invention. DETAILED DESCRIPTION

[0042] In order to better understand the technical solution of the present invention, the specific implementation mode of the present invention is described in detail below with reference to the accompanying drawings.

[0043] The online high-efficiency load reduction control method based on wind field forecast proposed by the present invention is as follows: Figure 1 As shown, the following steps are included:

[0044] (1) Obtain the load attack angle and sideslip angle calculated in real time on the arrow.

[0045] In one possible implementation, the calculation method of the load angle of attack and sideslip angle is as follows: during the flight, according to the flight altitude of the launch vehicle, real-time wind field information, including wind speed and wind direction, is obtained, and the projection of the wind vector in the launch coordinate system is calculated; the launch vehicle body speed is obtained through the navigation information on the launch vehicle, and based on the launch vehicle body speed and the projection of the wind vector in the launch coordinate system, the launch coordinate system airspeed vector and airspeed magnitude are obtained, thereby obtaining the load angle of attack and sideslip angle. The details are as follows:

[0046] Calculation method Projection of wind vector in the launch coordinate system:

[0047]

[0048] In the formula, G E is the transformation matrix from the geocentric coordinate system to the launch coordinate system, E T is the transformation matrix from the local horizontal coordinate system to the geocentric coordinate system, and They are the wind speed and wind direction interpolated according to the flight altitude of the launch vehicle;

[0049] Calculate the launch frame airspeed vector:

[0050]

[0051] In the formula, is the velocity of the launch vehicle obtained through the navigation information on the launch vehicle;

[0052] Calculate airspeed:

[0053]

[0054] Calculate the load angle of attack and sideslip angle:

[0055] 1) Calculate the projection of the airspeed vector on the arrow system:

[0056]

[0057] In the formula, B G is the transformation matrix from the launch coordinate system to the rocket body coordinate system;

[0058] 2) Calculate the load attack angle α a , sideslip angle β a :

[0059]

[0060] Where atan represents the inverse tangent function.

[0061] (2) The load angle of attack and sideslip angle are limited, and after the gain control network calculation, the angle of attack control command is generated. The attitude control system combines the load reduction demand and the guidance and correction capability to implement direct angle of attack control in the load-sensitive area.

[0062] 1) Limit the load attack angle and sideslip angle by:

[0063] if but if but

[0064] if but if but

[0065] in, For various parameters, it is preferred to set them to 1.5° and 1.5° (Note: converted to radians for use), After handling the limiting load angle of attack and sideslip angle.

[0066] 2) Generate angle of attack control instructions The specific method is:

[0067]

[0068] in, is the gain parameter;

[0069] It is the angle of attack control network; is the discrete network numerator coefficient, is the discrete network sub-coefficient;

[0070] It is the side slip angle control network; is the discrete network numerator coefficient, is the discrete network mesh coefficient.

[0071] (3) Generate pitch and yaw feedback control commands, implement active load reduction control, and compensate for the errors caused by angle of attack control.

[0072] Generate pitch and yaw feedback control instructions L1 and L2 as follows:

[0073]

[0074] in, is the pitch angle deviation, Δψ C is the yaw angle deviation, is the gain parameter, and D ψ (z) are pitch and yaw network parameters, respectively, and They are the pitch and yaw guidance network parameters or the table feedback load shedding network parameters. Guidance and table feedback load shedding are used in different time periods. Table feedback load shedding is used in high wind areas, and guidance is used after passing through high wind areas. z and ω y are the pitch and yaw angular velocities respectively.

[0075] (4) Simulation analysis

[0076] Based on the angle deviation + table feedback control, take the angle of attack feedback control gain A comparative analysis is conducted on the load reduction effect of whether or not the angle of attack feedback control is applied. Figure 2 As shown in the figure, the black line is the load reduction qa value under the original control, the red line is the comprehensive load reduction qa value after adding the angle of attack feedback, and the blue line is the comprehensive load reduction qa value with angle of attack feedback but without the original active load reduction (adding table feedback). As can be seen from the figure, during the period of shear wind action, the angle of attack feedback has a more obvious load reduction effect, and has a better load reduction effect than only using active load reduction (adding table feedback). During the period of steady wind action, the angle of attack feedback can ensure that qa has a smaller value, but the qa value is larger than when it is not used.

[0077] It is to be understood that the present invention is described by way of embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and embodiments that can fall within the scope of the claims of this application all fall within the scope protected by the present invention.

[0078] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. An online high-efficiency load reduction control method based on wind field forecast, characterized in that: include: Obtain the load attack angle and sideslip angle calculated in real time on the arrow; After limiting the load angle of attack and sideslip angle and calculating the gain control network, the angle of attack control command is generated. The attitude control system combines the load reduction demand and the guidance and correction capability to implement direct angle of attack control in the load-sensitive area. Generate pitch and yaw feedback control commands, implement active load reduction control, and compensate for errors caused by angle of attack control.

2. The online high-efficiency load reduction control method based on wind field forecast according to claim 1 is characterized in that: The load attack angle and sideslip angle are limited in the following way: if but if but if but if but in, are the various parameters, is the load angle of attack and sideslip angle after limiting processing, α a is the load attack angle, β a is the sideslip angle.

3. The online high-efficiency load reduction control method based on wind field forecast according to claim 2 is characterized in that: Angle of attack control command The generation method is: in, is the gain parameter; It is the angle of attack control network; is the discrete network numerator coefficient, is the discrete network sub-coefficient; It is the side slip angle control network; is the discrete network numerator coefficient, is the discrete network mesh coefficient.

4. The online high-efficiency load reduction control method based on wind field forecast according to claim 1 is characterized in that: The pitch and yaw feedback control commands L1 and L2 are calculated as follows: L2=a 0ψ ·D ψ (z)·ψ C in, is the pitch angle deviation, Δψ C is the yaw angle deviation, a 0ψ , B ψ is the gain parameter, and D ψ (z) are pitch and yaw network parameters, respectively, and They are the pitch and yaw guidance network parameters or the table feedback load shedding network parameters. Guidance and table feedback load shedding are used in different time periods. Table feedback load shedding is used in high wind areas, and guidance is used after passing through high wind areas. z and ω y are the pitch and yaw angular velocities, It is the angle of attack control command.

5. The online high-efficiency load reduction control method based on wind field forecast according to claim 1 is characterized in that: The load angle of attack and sideslip angle are calculated as: During the flight, real-time wind field information, including wind speed and wind direction, is obtained according to the flight altitude of the carrier rocket, and the projection of the wind vector in the launch coordinate system is calculated. The carrier rocket body speed is obtained through the navigation information on the carrier rocket, and based on the carrier rocket body speed and the projection of the wind vector in the launch coordinate system, the launch coordinate system airspeed vector and airspeed magnitude are obtained, thereby obtaining the load angle of attack and sideslip angle.

6. The online high-efficiency load reduction control method based on wind field forecast according to claim 5 is characterized in that: The projection of the wind vector in the launch coordinate system is calculated as: In the formula, G E is the transformation matrix from the geocentric coordinate system to the launch coordinate system, E T is the transformation matrix from the local horizontal coordinate system to the geocentric coordinate system, and They are the wind speed and wind direction interpolated according to the flight altitude of the launch vehicle; The airspeed vector of the launch coordinate system is calculated as: In the formula, is the velocity of the launch vehicle obtained through the navigation information on the launch vehicle; The airspeed is calculated as:

7. The online high-efficiency load reduction control method based on wind field forecast according to claim 5 is characterized in that: The load attack angle and sideslip angle are calculated as follows: Calculate the projection of the airspeed vector on the arrow system: In the formula, B G is the transformation matrix from the launch coordinate system to the rocket body coordinate system; Calculate the load attack angle α a , sideslip angle β a :

8. A computer program product, characterized in that: When the computer program product is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

9. An arrow computing terminal, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method as claimed in any one of claims 1 to 7 when executing the computer program.

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