A fairing homing control and safety obstacle avoidance method resistant to high-altitude wind interference

Abstract

The application discloses a method for homing control and safe obstacle avoidance of a fairing against high-altitude wind disturbance. Before launching of a carrier rocket, a plurality of target points and obstacle avoidance points are determined in a fairing falling area range. After a wing parachute starts to work, a preferred falling point is calculated first, and a priority identifier is assigned. Then, a predicted falling point of the wing parachute is calculated. A real-time predicted falling point and a distance from a nearest obstacle avoidance point are calculated. If the distance is greater than an obstacle avoidance safety distance, the original flight target point is maintained. If the distance is smaller than the obstacle avoidance safety distance, a sub-priority preferred falling point is selected, and the above calculation process is repeated until a target point with a predicted falling point and a distance from a nearest obstacle avoidance point greater than the obstacle avoidance safety distance is selected as a preferred flight target point and a preferred flight path. The application can make the wing parachute stably and accurately land in a target point area range under the condition of real-time track of the wing parachute disturbed by high-altitude wind, and can effectively avoid the obstacle avoidance area, which has far-reaching significance for research in the field of spacecraft returning and landing technology.

Description

Technical Field

[0001] This invention relates to a method for controlling the landing area of ​​a launch vehicle fairing by using a controllable parachute to achieve homing control and safe obstacle avoidance against high-altitude wind interference, thereby achieving control of the launch vehicle fairing landing area. It belongs to the field of spacecraft return and landing technology. Background Technology

[0002] After the fairing separates from the main rocket body and rises to its highest point, it falls freely. When it reaches below 20km, the speed and attitude of the fairing tend to stabilize, the recovery system starts to activate, and the parachutes of each stage open one by one to reduce the descent speed of the fairing. After the wing parachute of the final stage opens and stabilizes, the fairing completes its return and landing according to the predetermined procedure under the control of the homing system.

[0003] After separating from the main rocket body, the launch vehicle fairing fell freely to the ground without control, with a dispersion range of 2000 km. 2 The above describes the use of gliding parachutes, which can effectively reduce the dispersion range. However, when the parachute's homing capability is insufficient to cover the entire landing area, and considering the dispersion characteristics of the landing area, controllable parachutes cannot achieve precise and controllable recovery of the launch vehicle fairing, nor can they avoid villages, towns, and other areas where landing is impossible. Therefore, there is an urgent need to design a multi-target homing method that is resistant to high-altitude wind interference and has obstacle avoidance capabilities to achieve better homing results. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a fairing homing control and obstacle avoidance method that resists high-altitude wind interference. It achieves precise avoidance of the obstacle avoidance area under the premise of stable and efficient landing, targeting the landing target point and the obstacle avoidance area. This has profound significance for related research in the field of spacecraft return and landing technology.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] A fairing homing control and obstacle avoidance method to resist high-altitude wind interference includes:

[0007] S1: Before the launch of the carrier rocket, multiple target points and obstacle avoidance points are determined within the fairing landing area. After the parachute starts working, the preferred target point is calculated as the landing point and assigned a priority label.

[0008] S2: Calculate the predicted flight trajectory of the paraglider and calculate the predicted landing point based on the flight trajectory;

[0009] S3: Based on the calculated predicted landing point of the parachute, calculate the distance between the predicted landing point of the parachute and each obstacle avoidance point, and determine the nearest obstacle avoidance point.

[0010] If the distance between the predicted landing point of the paraglider and the nearest obstacle avoidance point is less than the obstacle avoidance safety distance, then a flight target point with the second lowest priority is selected; and the above calculation process is repeated for the reselected target point until a target point with a predicted landing point and a distance between the nearest obstacle avoidance point and the obstacle avoidance safety distance is selected as the optimal flight strategy.

[0011] Furthermore, step S1, which calculates the preferred target point as the landing point, specifically involves:

[0012] S1.1 Calculate the distance between the parachute projection point and each target point;

[0013] S1.2 Sort each target point according to its distance and set the priority of each target point, with the closest target point having the highest priority and the farthest target point having the lowest priority.

[0014] Furthermore, the distance between the parachute projection point and each target point is calculated using the following formula:

[0015]

[0016] Where Distance is the distance from the parachute projection point to any target point, radius is the Earth's radius, La_Para is the latitude of the parachute projection point, Lon_Para is the longitude of the parachute projection point, La_Destination is the latitude of any target point, and Lon_Destination is the longitude of any target point.

[0017] Furthermore, step S2 calculates the predicted flight trajectory of the paraglider and calculates the predicted landing point based on the flight trajectory, specifically as follows:

[0018] When the paraglider is gliding, i.e. in a straight-line motion, assuming that the horizontal velocity of the paraglider's straight-line motion is ΔV greater than that of its turning motion, the predicted flight trajectory is calculated using recursive formulas (2) to (6); if ΔV = 0, then formulas (7) to (10) are used for calculation:

[0019] x′=x+(V x -ΔVcosΦ+W x )τ (2)

[0020] y′=y+(V y +ΔVsinΦ+W y )τ (3)

[0021] V′ x =V x (4)

[0022] V′ y =V y (5)

[0023] ΔV=V* -V (6)

[0024] x′=x+(V x +W x )τ (7)

[0025] y′=y+(V y +W y )τ (8)

[0026] V′ x =V x (9)

[0027] V′ y =V y (10)

[0028] Among them, V * V is the horizontal velocity of the paraglider system when it is moving in a straight line; V is the horizontal velocity of the paraglider system when it is turning; ΔV is the difference between the horizontal velocity when it is moving in a straight line and the horizontal velocity when it is turning; Φ is the negative direction angle of the horizontal velocity V rotating counterclockwise to the Ox axis, 0 < Φ ≤ 2π;

[0029] Take a ground coordinate system Oxy, which is fixed to the Earth, with the origin O as the target point; the Ox axis points due east and the Oy axis points due north; the wind vector W is constant at a certain altitude layer;

[0030] At any given moment, the coordinates of the center of mass of the parachute system below the star are x and y in the coordinate system Oxy, and the projection of the velocity vector onto the x-axis is V. x The projection of V onto the y-axis is V. y ;

[0031] x, y, V x V y These are the current values; x', y', V' x , V′ y It is the value of the next time period; τ is the time period.

[0032] Furthermore, step S3 calculates the distance between the predicted landing point of the parachute and each obstacle avoidance point, and determines the nearest obstacle avoidance point, specifically as follows:

[0033] S3.1 Calculate the distance between the predicted landing point of the parachute and each obstacle avoidance point. The calculation method still uses formula (1), but replaces the longitude and latitude of the target point with the longitude and latitude of the obstacle avoidance point.

[0034] S3.2 Set the first obstacle avoidance point as the nearest obstacle avoidance point, set the distance between the parachute's predicted landing point and the first obstacle avoidance point as the nearest obstacle avoidance point distance, compare the parachute's predicted landing point with the distances of other obstacle avoidance points, and if there is an obstacle avoidance point that is closer, replace that obstacle avoidance point with the nearest obstacle avoidance point.

[0035] Furthermore, this invention also proposes a fairing homing control and obstacle avoidance system resistant to high-altitude wind interference, comprising:

[0036] Landing point priority determination module: Before the launch of the launch vehicle, multiple target points and obstacle avoidance points are determined within the fairing landing area. After the parachute starts working, the preferred target point is calculated as the landing point and assigned a priority label.

[0037] Predicted landing point determination module: Calculates the predicted flight trajectory of the paraglider and calculates the predicted landing point based on the flight trajectory;

[0038] Optimal flight strategy determination module: Based on the calculated predicted landing point of the paraglider, calculate the distance between the predicted landing point of the paraglider and each obstacle avoidance point, and determine the nearest obstacle avoidance point.

[0039] If the distance between the predicted landing point of the paraglider and the nearest obstacle avoidance point is less than the obstacle avoidance safety distance, then the next lowest priority flight target point is selected; and the calculation is repeated for the reselected target point until the optimal flight strategy is selected as the target point whose predicted landing point is greater than the obstacle avoidance safety distance.

[0040] The present invention also proposes a processor for running a program, wherein the program executes the fairing homing control and safety obstacle avoidance method for resisting high-altitude wind interference.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] (1) This invention proposes an innovative method for the fixed-point recovery and obstacle avoidance of rocket fairings by a controllable parachute, which achieves precise avoidance of the obstacle avoidance area under the premise of stable and efficient landing;

[0043] (2) The method of the present invention can update the optimal target point in real time and make real-time judgment on the control mode of the paraglider based on the real-time flight status parameters of the paraglider, thus achieving effective control over the overall process of paraglider recovery and obstacle avoidance. Attached Figure Description

[0044] Figure 1 This is a flowchart of the flight optimal strategy calculation process of this invention;

[0045] Figure 2 This is a diagram showing the straight-line flight relationship of the paraglider trajectory of this invention. Detailed Implementation

[0046] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0047] After completing its booster liftoff function, the launch vehicle fairing separates from the main body and falls freely to the ground without control, with a dispersion range of up to 2000 km. 2 The above describes the use of paragliders with gliding capabilities, which can effectively reduce the dispersion area. Paraglider homing can typically employ methods such as fixed-point homing, fixed-route homing, or multi-target homing. When the paraglider's homing capability is insufficient to cover the entire landing area, a multi-target homing method with obstacle avoidance capabilities can achieve better homing results, taking into account the characteristics of the landing area dispersion.

[0048] This invention calculates and locks onto the optimal target point among multiple target points, continuously updates the optimal target point information during flight, and manipulates the paraglider to fly towards the optimal target point. Furthermore, it achieves an optimal flight strategy of landing point prediction and obstacle avoidance during the selection of the optimal target point (landing point) and optimal route.

[0049] The calculation method for the optimal flight strategy involves the following steps, achieving homing control and safe obstacle avoidance:

[0050] 1. Before the launch of the carrier rocket, multiple target points and obstacle avoidance points are determined within the fairing landing area. After the paraglider starts working, the preferred target point is calculated as the landing point and assigned a priority label.

[0051] 2. Calculate the predicted flight trajectory of the paraglider, and calculate the predicted landing point based on the flight trajectory;

[0052] 3. Based on the calculated predicted landing point of the parachute, calculate the distance between the predicted landing point of the parachute and each obstacle avoidance point, and determine the nearest obstacle avoidance point;

[0053] If the distance between the predicted landing point of the paraglider and the nearest obstacle avoidance point is less than the obstacle avoidance safety distance, then a flight target point with the second lowest priority is selected; and the above calculation process is repeated for the reselected target point until a target point with a predicted landing point and a distance between the nearest obstacle avoidance point and the obstacle avoidance safety distance is selected as the optimal flight strategy.

[0054] The calculation process for homing control and safe obstacle avoidance (optimal flight strategy) is as follows: Figure 1 As shown.

[0055] The method for calculating the preferred landing point and assigning priority labels is as follows:

[0056] 1.1 Calculate the distance between the parachute projection point and each target point using the following formula:

[0057]

[0058] Where Distance is the distance between the parachute projection point and any target point, radius is the Earth's radius, La_Para is the latitude of the parachute projection point, Lon_Para is the longitude of the parachute projection point, La_Destination is the latitude of any target point, and Lon_Destination is the longitude of any target point.

[0059] 1.2 Sort each target point according to its distance and set the priority of each target point, with the closest target point having the highest priority and the farthest target point having the lowest priority.

[0060] II. The calculation methods for the parachute homing control trajectory and predicted landing point are as follows:

[0061] When the paraglider is gliding, i.e., in a straight line, its trajectory simulation motion can be calculated using the following recursive formula. Where V * V is the horizontal velocity of the paraglider system when moving in a straight line; V is the horizontal velocity of the paraglider system when turning; ΔV is the difference between the horizontal velocity during straight-line motion and the horizontal velocity during turning. Φ is the negative direction angle of the horizontal velocity V rotating counterclockwise to the Ox axis, 0 < Φ ≤ 2π. A ground coordinate system Oxy is established, fixed to the Earth, with the origin O as the target point; the Ox axis points due east, and the Oy axis points due north. The wind vector W is constant at a certain altitude. At any given moment, the coordinates of the paraglider system's center of mass below the star in the coordinate system Oxy are x, y, and the projection of the velocity vector onto the x-axis is V. x The projection of V onto the y-axis is V. y x, y, V x V y These are the current values; x', y', V' x , V′ y This is the value of the next time period. τ is the time period. See the flight diagram for the paraglider in straight flight. Figure 2 As shown. When the paraglider is in a gliding, i.e., straight-line motion state, assuming that the horizontal velocity of the paraglider's straight-line motion is ΔV greater than that of its turning motion, its trajectory simulation motion state can be calculated using recursive formulas (2) to (6). If ΔV = 0, then formulas (7) to (10) can be used. The straight-line flight relationship diagram of the paraglider trajectory of this invention is shown in the figure. Figure 2 .

[0062] x′=x+(V x =ΔVcosΦ+W x )τ (2)

[0063] y′=y+(V y +ΔVsinΦ+W y )τ (3)

[0064] V′ x =Vx (4)

[0065] V′ y =V y (5)

[0066] ΔV=V * -V (6)

[0067] x′=x+(V x +W x )τ (7)

[0068] y′=y+(V y +W y )τ (8)

[0069] V′ x =V x (9)

[0070] V′ y =V y (10)

[0071] Third, after calculating the predicted landing point of the paraglider based on its predicted flight trajectory, it is necessary to calculate the distance between the predicted landing point of the paraglider and each obstacle avoidance point, and then calculate the nearest obstacle avoidance point.

[0072] If the distance between the predicted landing point of the paraglider and the nearest obstacle avoidance point is less than the obstacle avoidance safety distance, then a second-lowest priority flight target point is selected. This calculation process is repeated for the reselected target point until a target point whose predicted landing point is greater than the obstacle avoidance safety distance is selected as the optimal flight strategy.

[0073] The method for calculating the distance between the predicted landing point and the nearest obstacle avoidance point of the parachute is as follows:

[0074] 1. Calculate the distance between the predicted landing point of the parachute and each obstacle avoidance point. The calculation method still uses formula (1), but replaces the longitude and latitude of the target point with the longitude and latitude of the obstacle avoidance point.

[0075] 2. Set the first obstacle avoidance point as the nearest obstacle avoidance point, and set the distance between the parachute's predicted landing point and the first obstacle avoidance point as the nearest obstacle avoidance point distance. Compare the distance between the parachute's predicted landing point and other obstacle avoidance points. If there is an obstacle avoidance point that is closer, replace that obstacle avoidance point with the nearest obstacle avoidance point.

[0076] This invention addresses the challenge of enabling paragliders to land stably and accurately within the target area while effectively avoiding obstacle avoidance zones, even when high-altitude winds interfere with their real-time flight path. This invention has profound significance for research in the field of spacecraft return and landing technology.

[0077] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0078] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for homing control and safe obstacle avoidance of a fairing against high-altitude wind disturbance, characterized in that, The method comprises the following steps: S1: determining a plurality of target points and barrier avoidance points in the fairing falling area range of the launch vehicle before the launch of the launch vehicle, calculating a preferred target point as a falling point after the wing parachute starts to work, and giving a priority identifier; S2: calculating a predicted flight trajectory of the wing parachute, and calculating a predicted falling point according to the flight trajectory; S3: calculating the distance between the predicted falling point of the wing parachute and each barrier avoidance point, and determining the nearest barrier avoidance point; If the distance between the predicted falling point of the wing parachute and the nearest barrier avoidance point is less than a barrier avoidance safety distance, a flight target point with a second-lowest priority is reselected; and the above calculation process is repeated for the reselected target point until a target point with a predicted falling point having a distance greater than the barrier avoidance safety distance from the nearest barrier avoidance point is selected as an optimal flight strategy.

2. The fairing homing control and obstacle avoidance method for resisting high-altitude wind interference according to claim 1, characterized in that: The step S1 of calculating a preferred target point as a falling point specifically comprises the following steps: S1.1: calculating the distance between the projection point of the wing parachute and each target point; S1.2: sorting each target point according to the distance, and setting the priority of each target point, with the highest priority for the nearest distance and the lowest priority for the farthest distance.

3. The method of claim 1, wherein the method further comprises: determining a distance between the aircraft and the object; and determining whether the object is a bird based on the determined distance. The step S2 of calculating a predicted flight trajectory of the wing parachute and calculating a predicted falling point according to the flight trajectory specifically comprises the following steps: When the parafoil is in the glide, i.e. straight motion state, it is assumed that the horizontal speed of the parafoil in the straight motion is greater than that in the turning motion , then the predicted flight trajectory is calculated using recursive formulas (2) - (6); if , then formulas (7) - (10) are used for calculation: （2） （3） （4） （5） （6） （7） （8） （9） （10） wherein, is the horizontal velocity of the parafoil system in the case of rectilinear motion; is the horizontal velocity of the parafoil system in the case of turning motion; is the difference between the horizontal velocity in rectilinear motion and the horizontal velocity in turning motion; is the negative angle of rotation of the horizontal velocity V counterclockwise to the negative direction of the Ox axis, π; A ground coordinate system Oxy is taken, the coordinate system is fixed to the earth, the origin O is a target point, the Ox axis points to the east, and the Oy axis points to the north; a wind vector W is a constant at a certain height layer; The coordinates of the center of mass of the parafoil system in the coordinate system Oxy at any moment are x, y, the projection of the velocity vector on the x axis is , and the projection on the y axis is ; is the current value; , , τ is the time period.

4. The method of claim 1, wherein the method further comprises: determining a distance between the aircraft and the object; and determining whether the object is a bird based on the determined distance. The step S3 of calculating the distance between the predicted falling point of the wing parachute and each barrier avoidance point and determining the nearest barrier avoidance point specifically comprises the following steps: S3.1: calculating the distance between the predicted falling point of the wing parachute and each barrier avoidance point, replacing the longitude and latitude of the target point with the longitude and latitude of the barrier avoidance point; S3.2: taking the first barrier avoidance point as the nearest barrier avoidance point, taking the distance between the predicted falling point of the wing parachute and the first barrier avoidance point as the nearest barrier avoidance point distance, and comparing the distance between the predicted falling point of the wing parachute and other barrier avoidance points with the nearest barrier avoidance point distance; if there is a barrier avoidance point with a closer distance, the barrier avoidance point is replaced with the nearest barrier avoidance point.

5. A fairing homing control and safety obstacle avoidance system against high altitude wind disturbance, characterized in that The method comprises the following steps: A falling point priority determination module: determining a plurality of target points and barrier avoidance points in the fairing falling area range of the launch vehicle before the launch of the launch vehicle, calculating a preferred target point as a falling point after the wing parachute starts to work, and giving a priority identifier; A predicted falling point determination module: calculating a predicted flight trajectory of the wing parachute, and calculating a predicted falling point according to the flight trajectory; An optimal flight strategy determination module: calculating the distance between the predicted falling point of the wing parachute and each barrier avoidance point, and determining the nearest barrier avoidance point; If the distance between the predicted falling point of the wing parachute and the nearest barrier avoidance point is less than a barrier avoidance safety distance, a flight target point with a second-lowest priority is reselected; and the above calculation process is repeated for the reselected target point until a target point with a predicted falling point having a distance greater than the barrier avoidance safety distance from the nearest barrier avoidance point is selected as an optimal flight strategy.

6. The fairing homing control and safety obstacle avoidance system according to claim 5, wherein: The step of calculating a preferred target point as a falling point specifically comprises the following steps: S1.1: calculating the distance between the projection point of the wing parachute and each target point; S1.2: sorting each target point according to the distance, and setting the priority of each target point, with the highest priority for the nearest distance and the lowest priority for the farthest distance.

7. The fairing homing control and safety obstacle avoidance system according to claim 5, wherein: The method comprises the following steps of: calculating a predicted flight trajectory of the parafoil, and calculating a predicted landing point according to the flight trajectory, specifically: When the parafoil is in the glide, i.e. straight motion state, it is assumed that the horizontal speed of the parafoil in the straight motion is greater than that in the turning motion then the predicted flight trajectory is calculated using recursive formulas (2) - (6); if then formulas (7) - (10) are used for calculation: （2） （3） （4） （5） （6） （7） （8） （9） （10） wherein, is the horizontal velocity of the parafoil system in the case of rectilinear motion; is the horizontal velocity of the parafoil system in the case of turning motion; is the difference between the horizontal velocity in rectilinear motion and the horizontal velocity in turning motion; is the negative angle of rotation of the direction of the horizontal velocity V counterclockwise to the negative direction of the Ox axis, π; A ground coordinate system Oxy is taken, the coordinate system is fixed to the earth, the origin O is the target point, the Ox axis points to the east, and the Oy axis points to the north; a wind vector W is constant at a certain height layer; The coordinates of the center of mass of the parafoil system in the coordinate system Oxy at any moment are x, y, the projection of the velocity vector on the x axis is , and the projection on the y axis is ; is the current value; , , τ is the time period.

8. The fairing homing control and safety obstacle avoidance system according to claim 5, wherein: The method further comprises the following steps of: calculating distances between the predicted landing point of the parafoil and each obstacle avoidance point, and determining a nearest obstacle avoidance point, specifically: S3.

1. Calculate the distance between the predicted landing point of the parafoil and each obstacle avoidance point, and replace the longitude and latitude of the target point with the longitude and latitude of the obstacle avoidance point; S3.

2. Set the first obstacle avoidance point as the nearest obstacle avoidance point, set the distance between the predicted landing point of the parafoil and the first obstacle avoidance point as the distance to the nearest obstacle avoidance point, and compare the distances between the predicted landing point of the parafoil and other obstacle avoidance points; if there is a closer obstacle avoidance point, replace the nearest obstacle avoidance point with the obstacle avoidance point.

9. A processor, comprising: The processor is configured to run a program, and the program performs the method for homing control and safe obstacle avoidance of the fairing against high-altitude wind interference according to any one of claims 1-4.

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