Hydrodynamic parameter identification-based rocket maritime launching and takeoff drift amount analysis method

Abstract

The invention discloses a hydrodynamic parameter identification-based rocket maritime launching take-off drift amount analysis method, and relates to the technical field of spaceflight, and the method comprises the steps: obtaining a rolling minimum distance Ds1 according to the boundary condition of a rolling direction; obtaining a pitching minimum distance Ds2 according to the boundary condition of the pitching direction; the take-off time tq of the ignited rocket body is calculated according to the boundary condition of the pitching direction; according to the takeoff time tq of the ignited rocket body, compensating for the extension of the rocket body ignition thrust-weight ratio balance time caused by the acceleration in the vertical direction generated by the rocket body in the pitching direction, and obtaining a comprehensive minimum distance # imgabs0 #; if the rolling minimum distance Ds1, the pitching minimum distance Ds2 and the comprehensive minimum distance # imgabs1 # all meet the drift distance safety design requirements; if yes, the takeoff drift distance calculation result is matched with the hydrodynamic condition of the launching ship, and simulation is ended. According to the method, the complexity of the model can be simplified through transverse and longitudinal independent analysis, the calculation complexity is reduced, and it can be ensured that the calculation result of the take-off offset envelopes the comprehensive motion influence of the launching ship.

Description

Technical Field

[0001] The present application relates to the field of aerospace technology, and in particular to a method for analyzing the drift of a rocket launched and taken off at sea based on hydrodynamic parameter identification. Background Art

[0002] The sea launch of a carrier rocket is a new, efficient, flexible and economical launch mode. It can flexibly select the launch point and landing area, and can meet the payload launch needs of various orbits. At the same time, the sea launch site and the total launch cost can be effectively reduced, and the launch capability can be quickly formed. Research on the sea launch of carrier rocket technology has important technological innovation and market development significance.

[0004] When a carrier rocket is launched at sea, the launch ship will be affected by wind and waves and will move sideways and vertically, which will cause the drift of the rocket to be more obvious than that of land launch. In addition, the launch support system of sea-launched rockets is more complicated. The drift will directly affect the safety of the rocket's take-off phase. Therefore, it is an important task in the safety analysis of sea-launched rockets to study the drift of the rocket during the launch phase according to the hydrodynamic parameters of the launch ship and finally determine the launch boundary conditions.

[0005] The launch ship has complex motions such as roll and pitch when anchored. The period, amplitude and phase correlation of the motions in the two directions are weak, and the coupling and superposition of various motions will bring difficulties to the modeling and calculation of the drift of the launch vehicle after takeoff. The existing calculation methods of takeoff offset are usually complicated and cannot simplify the impact of the complex hydrodynamic characteristics of the launch ship on the modeling difficulty, making the calculation difficult. Summary of the invention

[0006] The purpose of this application is to provide a method for analyzing the takeoff drift of a rocket launched at sea based on hydrodynamic parameter identification, which can simplify the model complexity and reduce the calculation complexity through independent lateral and longitudinal analysis, and can ensure that the calculation results of the takeoff offset envelope the comprehensive motion influence of the launching ship.

[0007] To achieve the above-mentioned purpose, the present application provides a method for analyzing the drift of rocket launch at sea based on hydrodynamic parameter identification, comprising the following steps: S1: placing a rocket body on a launch ship, and placing a supporting device in the roll direction, the supporting device being connected to the rocket body; taking the tail of the rocket body as the coordinate origin, taking the vertical direction facing the sky as the X-axis, taking the horizontal direction of the length of the supporting device at the time of rocket body ignition as the Y-axis, determining the Z-axis according to the right-hand rule, the Z-axis being perpendicular to the length direction of the supporting device, constructing a launch coordinate system according to the coordinate origin, the X-axis, the Y-axis and the Z-axis, and constructing a four-dimensional space coordinate (X, Y, Z, t) according to the launch coordinate system and the time relationship t; S2: determining the boundary conditions in the roll direction and the boundary conditions in the pitch direction at the time of rocket body ignition according to the hydrodynamic characteristics of the launch ship; wherein the boundary conditions in the roll direction are: sinusoidal periodic shaking, the shaking angle amplitude is A1, the shaking period is T1, the distance between the bottom support position of the rocket body and the supporting device in the roll direction is L1, and the distance between the bottom support position of the rocket body and the shaking center is L2; The boundary conditions in the pitch direction are: sinusoidal periodic sway, the sway angle amplitude is A2, the sway period is T2, the vertical distance between the center of mass of the arrow body and the pitch direction is L3, and the horizontal distance between the center of mass of the arrow body and the sway center is L4; S3: According to the boundary conditions in the roll direction, the minimum roll distance Ds1 is obtained, and it is analyzed whether the minimum roll distance Ds1 meets the drift safety design requirements. If not, the hydrodynamic parameters in the pitch direction of the launch ship are reduced; if they are satisfied, S7 is executed; S4: According to the pitch direction, the minimum roll distance Ds1 is obtained. The minimum pitch distance Ds2 is obtained according to the boundary conditions in the pitch direction, and it is analyzed whether the minimum pitch distance Ds2 meets the drift safety design requirements. If not, the hydrodynamic parameters of the launch ship in the pitch direction are reduced; if satisfied, S7 is executed; S5: the take-off time tq of the rocket body after ignition is calculated according to the boundary conditions in the pitch direction; S6: according to the take-off time tq of the rocket body after ignition, the lengthening of the time for balancing the thrust-to-weight ratio of the rocket body caused by the vertical acceleration of the rocket body in the pitch direction is compensated to obtain the comprehensive minimum distance S7: Using drift safety design requirements for comprehensive minimum distance For analysis, if the minimum distance If the drift safety design requirements are met, the takeoff drift calculation results match the launch ship hydrodynamic conditions, and the simulation ends; if the comprehensive minimum distance If the drift safety design requirements are not met, the hydrodynamic parameters of the launch ship in the roll or pitch direction shall be reduced.

[0008] As above, wherein the sub-steps for obtaining the minimum roll distance Ds1 according to the boundary conditions in the roll direction are as follows: S31: Calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the first moment according to the boundary conditions in the roll direction; Calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the second moment according to the boundary conditions in the roll direction; Calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the third moment according to the boundary conditions in the roll direction; wherein the first moment represents the moment when the roll direction is in the horizontal position of the Y axis and the X axis is tilted to the left at 0; the second moment represents the moment when the roll direction is tilted to 0.5×A1 on the left side of the X axis; the third moment represents the moment when the roll direction is tilted to the left side of the X axis to the maximum inclination angle of the sway angle amplitude A1 in the boundary conditions of the roll direction; S32: Calculate the displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the first moment; Calculate the displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the second moment S33: calculating the displacement of the supporting point M in the launch coordinate system during the opening process of the supporting device corresponding to the roll direction at the first moment; calculating the displacement of the supporting point M in the launch coordinate system during the opening process of the supporting device corresponding to the roll direction at the third moment, wherein the supporting point M is the contact point between the upper end of the left side of the supporting device and the rocket body; S34: calculating the first distance between the takeoff drift curve function in the launch coordinate system during the rocket body ignition and takeoff process at the first moment and the displacement of the supporting point M in the launch coordinate system during the corresponding opening process of the supporting device; calculating the second distance between the takeoff drift curve function in the launch coordinate system during the rocket body ignition and takeoff process at the second moment and the displacement of the supporting point M in the launch coordinate system during the corresponding opening process of the supporting device; calculating the third distance between the takeoff drift curve function in the launch coordinate system during the rocket body ignition and takeoff process at the third moment and the displacement of the supporting point M in the launch coordinate system during the corresponding opening process of the supporting device; and taking the minimum value among the first distance, the second distance and the third distance as the minimum roll distance Ds1.

[0009] As above, wherein the sub-steps for obtaining the minimum pitch distance Ds2 according to the boundary conditions in the pitch direction are as follows: S41: Calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fourth moment according to the boundary conditions in the pitch direction; Calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fifth moment according to the boundary conditions in the pitch direction; Calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the sixth moment according to the boundary conditions in the pitch direction; Calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the seventh moment according to the boundary conditions in the pitch direction; wherein the fourth moment represents the pitch direction in The pitch angle of the arrow body is 0°, and the time when the center of mass of the arrow body moves upward along the X-axis is 0s; the fifth moment represents the moment when the pitch angle of the arrow body is the sway angle amplitude A2 in the boundary condition of the pitch direction, and the time when the center of mass of the arrow body reaches the highest point along the X-axis is 0.25×T2, and T2 is the sway period in the boundary condition of the pitch direction; the sixth moment represents the moment when the pitch angle of the arrow body is 0°, and the time when the center of mass of the arrow body moves downward along the X-axis is 0.5×T2; the seventh moment represents the moment when the pitch angle of the arrow body is -A2, and the time when the center of mass of the arrow body reaches the lowest point along the X-axis is 0.75×T2; S42: Calculate the support device corresponding to the roll direction of the fourth moment Calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device; calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the fifth moment; calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the sixth moment; calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the seventh moment; wherein the supporting point M is the contact point between the upper end of the left side of the supporting device and the rocket body; S43: calculate the fourth distance between the takeoff drift amount curve function in the launch coordinate system during the ignition and takeoff process of the rocket body at the fourth moment and the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device; calculate the fourth distance between the fourth distance between the fourth distance between the fourth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance between the fifth distance The fifth distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fifth moment and the displacement of the supporting point M in the launch coordinate system during the corresponding supporting device opening process is calculated; the sixth distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the sixth moment and the displacement of the supporting point M in the launch coordinate system during the corresponding supporting device opening process is calculated; the seventh distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the seventh moment and the displacement of the supporting point M in the launch coordinate system during the corresponding supporting device opening process is calculated; the minimum value among the fourth moment, the fifth moment, the sixth moment and the seventh moment is taken as the minimum pitch distance Ds2.

[0010] As above, the sub-steps of calculating the take-off time tq of the rocket body after ignition according to the boundary conditions in the pitch direction are as follows: S51: Calculate the vertical acceleration a generated by the rocket body in the pitch direction according to the boundary conditions in the pitch direction ci , where the vertical acceleration a generated by the arrow body in the pitch direction is ci Including: the vertical acceleration a generated by the arrow body in the pitch direction at the fourth moment c1 , the vertical acceleration a generated by the arrow body in the pitch direction at the fifth moment c2 , the vertical acceleration a generated by the arrow body in the pitch direction at the sixth moment c3 and the vertical acceleration a of the arrow body in the pitch direction at the seventh moment c4 ; S52: The vertical acceleration a of the arrow body is generated according to the pitch direction ci Calculate the take-off time tq of the rocket body after ignition.

[0011] As above, the vertical acceleration a of the arrow body in the pitch direction is ci The expression is: Wherein, A2 is the sway angle amplitude in the boundary condition of the pitch direction; L3 is the vertical distance from the center of mass of the arrow body in the boundary condition of the pitch direction to the pitch direction; T2 is the sway period in the boundary condition of the pitch direction; t i is the time, i∈[1,4], t1 is the time from the rocket body ignition to take-off at the fourth moment, t2 is the time from the rocket body ignition to take-off at the fifth moment, t3 is the time from the rocket body ignition to take-off at the sixth moment, and t4 is the time from the rocket body ignition to take-off at the seventh moment.

[0012] As above, according to the take-off time tq of the rocket body after ignition, the time lengthening of the rocket body ignition thrust-to-weight ratio balance caused by the vertical acceleration of the rocket body in the pitch direction is compensated to obtain the comprehensive minimum distance The sub-steps are as follows: S61: subtract the take-off time tq from the time from the ignition of the rocket body to the take-off at the first moment to obtain the first compensated moment; subtract the take-off time tq from the time from the ignition of the rocket body to the take-off at the second moment to obtain the second compensated moment; subtract the take-off time tq from the time from the ignition of the rocket body to the take-off at the third moment to obtain the third compensated moment; S62: calculate the take-off drift amount curve function of the rocket body ignition and take-off process in the launch coordinate system at the first compensated moment according to the boundary conditions in the roll direction; calculate the take-off drift amount curve function of the rocket body ignition and take-off process in the launch coordinate system at the second compensated moment according to the boundary conditions in the roll direction; calculate the take-off drift amount curve function of the rocket body ignition and take-off process in the launch coordinate system at the third compensated moment according to the boundary conditions in the roll direction; S63: calculate the displacement of the support point M in the launch coordinate system during the opening process of the support device corresponding to the roll direction at the first compensated moment; calculate the displacement of the support point M in the launch coordinate system during the opening process of the support device corresponding to the roll direction at the second compensated moment The displacement of the supporting point M in the launch coordinate system; calculating the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the third compensation moment, wherein the supporting point M is the contact point between the upper end of the left side of the supporting device and the rocket body; S64: calculating the first compensated distance between the takeoff drift curve function in the launch coordinate system during the rocket body ignition and takeoff process at the first compensation moment and the displacement of the supporting point M in the launch coordinate system during the corresponding opening of the supporting device; calculating the second compensated distance between the takeoff drift curve function in the launch coordinate system during the rocket body ignition and takeoff process at the second compensation moment and the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device; calculating the third compensated distance between the takeoff drift curve function in the launch coordinate system during the rocket body ignition and takeoff process at the third compensation moment and the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device; taking the minimum value among the first compensated distance, the second compensated distance and the third compensated distance as the comprehensive minimum distance

[0013] As above, the takeoff drift curve function of the rocket body ignition takeoff process in the launch coordinate system at the first compensation time is: in, is the displacement of the center of mass of the arrow in the X-axis direction in the launch coordinate system at the first compensation moment; is the displacement of the arrow body mass center in the Y-axis direction in the launch coordinate system at the first compensation moment; is the displacement of the arrow body mass center in the Z-axis direction in the launch coordinate system at the first compensation moment; is the time after the rocket body is ignited at the first compensation moment; the takeoff drift curve function of the rocket body ignition takeoff process in the launch coordinate system at the second compensation moment is in, is the displacement of the center of mass of the arrow in the X-axis direction in the launch coordinate system at the second compensation moment; is the displacement of the arrow body mass center in the Y-axis direction in the launch coordinate system at the second compensation moment; is the displacement of the arrow body mass center in the Z-axis direction in the launch coordinate system at the second compensation moment; is the time after the rocket body is ignited at the second compensation time; the takeoff drift curve function of the rocket body ignition takeoff process in the launch coordinate system at the third compensation time is in, is the displacement of the center of mass of the arrow in the X-axis direction in the launch coordinate system at the third compensation moment; is the displacement of the arrow body mass center in the Y-axis direction in the launch coordinate system at the third compensation moment; is the displacement of the arrow body mass center in the Z-axis direction in the launch coordinate system at the third compensation moment; It is the time after the rocket body is ignited at the third compensation moment.

[0014] As above, the displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the first compensation moment is: in, is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the first compensation moment; is the displacement of the supporting point M of the supporting device in the Y-axis direction of the launch coordinate system after the rocket body is ignited at the first compensation moment; is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the first compensation moment; is the time after the rocket body is ignited at the first compensation moment; the displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the second compensation moment is in, is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the second post-compensation moment; is the displacement of the supporting point M of the supporting device in the Y-axis direction of the launch coordinate system after the rocket body is ignited at the second post-compensation moment; is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the second post-compensation moment; is the time after the rocket body is ignited at the second compensation moment; the displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the third compensation moment is in, is the displacement of the supporting point M of the supporting device in the X-axis direction of the launch coordinate system after the rocket body is ignited at the third post-compensation moment; is the displacement of the supporting point M of the supporting device in the Y-axis direction of the launch coordinate system after the rocket body is ignited at the third post-compensation moment; is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the third post-compensation moment; It is the time after the rocket body is ignited at the third compensation moment.

[0015] As above, the drift safety design requirements include at least: a first safety threshold, a second safety threshold and a third safety threshold; the first safety threshold is used to analyze whether the minimum roll distance Ds1 meets the drift safety design requirements. If the minimum roll distance Ds1 is greater than or equal to the first safety threshold, it is satisfied; if the minimum roll distance Ds1 is less than the first safety threshold, it is not satisfied; the second safety threshold is used to analyze whether the minimum pitch distance Ds2 meets the drift safety design requirements. If the minimum pitch distance Ds2 is greater than or equal to the second safety threshold, it is satisfied; if the minimum pitch distance Ds2 is less than the second safety threshold, it is not satisfied; the third safety threshold is used to analyze the comprehensive minimum distance Whether the drift safety design requirements are met, if the minimum distance is greater than or equal to the third safety threshold, then it is satisfied; if the comprehensive minimum distance If it is less than the third safety threshold, it is not satisfied.

[0016] As above, wherein the third safety threshold is 50 mm.

[0017] The beneficial effects achieved by this application are as follows:

[0018] (1) The method for analyzing the takeoff drift of a rocket launched at sea based on hydrodynamic parameter identification of the present application is a method for calculating the takeoff drift of a rocket during the takeoff process of launching at sea based on the hydrodynamic parameter identification of the launch ship. The method can determine the hydrodynamic boundary conditions of the launch ship (for example: roll angle amplitude, pitch angle amplitude and sway period, etc.), thereby ensuring that the takeoff drift of the rocket meets the drift safety design requirements.

[0019] (2) The method for analyzing the takeoff drift of a rocket launched at sea based on hydrodynamic parameter identification of the present application establishes four-dimensional spatial coordinates (X, Y, Z, t), models the spatial motion and time relationship in the launch coordinate system, simplifies the model complexity by independent lateral and longitudinal analysis, and further simplifies the influence of the complex hydrodynamic characteristics of the launch ship on the modeling difficulty, thereby reducing the computational complexity. At the same time, the safety of the takeoff drift during the ignition and takeoff process of the rocket at different movement moments in the roll direction or pitch direction can be analyzed, and the maximum risk point of the takeoff drift in the rolling direction and pitch direction shaking cycle is found respectively. A comprehensive analysis is performed based on the hydrodynamic characteristics of these two moments and the laws of rocket motion, thereby ensuring that the calculation result of the takeoff offset encompasses the comprehensive motion influence of the launch ship. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0021] Figure 1 The figure is a schematic diagram of the movement of the rocket body and the supporting device;

[0022] Figure 2 This is a schematic diagram of the model of the rolling motion of the rocket body on the launching ship;

[0023] Figure 3 This is a schematic diagram of the model of the pitch and roll motion of the rocket body on the launching ship;

[0024] Figure 4 The figure is a schematic diagram of the rolling direction of the rocket body on the launching ship;

[0025] Figure 5 Schematic diagram of the pitch direction of the rocket body on the launching ship. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0027] like Figure 1-5 As shown, the present application provides a method for analyzing the drift of rocket launch and takeoff at sea based on hydrodynamic parameter identification, comprising the following steps:

[0028] S1: The rocket body is placed on the launching ship, and a supporting device is arranged in the rolling direction, and the supporting device is connected to the rocket body; the tail of the rocket body is taken as the coordinate origin, the vertical direction facing the sky is taken as the X-axis (that is, the length direction of the rocket body when the hull of the launching ship is in a horizontal position and the rocket body is perpendicular to the hull), the horizontal direction of the length of the supporting device at the time of ignition of the rocket body is taken as the Y-axis, and the Z-axis is determined according to the right-hand rule, and the Z-axis is perpendicular to the length direction of the supporting device (that is, the Z-axis is the direction perpendicular to the length direction of the supporting device), and a launching coordinate system is constructed according to the coordinate origin, the X-axis, the Y-axis and the Z-axis, and the four-dimensional space coordinates (X, Y, Z, t) are constructed according to the launching coordinate system and the time relationship t.

[0029] Specifically, Figure 1 As shown, the rocket body is set at the tail of the launch ship. The launch ship is located at sea. In order to improve the safety of the rocket body during the shaking process of the launch ship before launch, a support device for the rocket body is added in the roll direction. The support device is passively opened after the rocket body is ignited, and the opening time of the support device is consistent with the rocket ignition time. The pitch and heave movements of the launch ship will cause the rocket to have periodic linear velocity and acceleration and other interferences in the vertical direction. The influence of the lateral movement of the launch ship on the rocket body take-off process is superimposed, causing the drift of the rocket body after ignition to be more complicated than that of land launch. The calculation of the safe distance between the rocket body take-off process and the support device and other equipment has become a necessary condition for the safety analysis of the sea launch of the carrier rocket.

[0030] S2: Determine the boundary conditions in the roll direction and the pitch direction at the time of rocket body ignition according to the hydrodynamic characteristics of the launching ship; wherein, the boundary conditions in the roll direction are: sinusoidal periodic shaking, the shaking angle amplitude is A1, the shaking period is T1, the distance between the bottom support position of the rocket body and the supporting device in the roll direction is L1, and the distance between the bottom support position of the rocket body and the shaking center is L2; ​​the boundary conditions in the pitch direction are: sinusoidal periodic shaking, the shaking angle amplitude is A2, the shaking period is T2, the vertical distance between the center of mass of the rocket body and the pitch direction is L3, and the horizontal distance between the center of mass of the rocket body and the shaking center is L4.

[0031] Specifically, an implementation example of L1, L2, L3 and L4 is as follows: Figure 4 and Figure 5 shown.

[0032] According to the actual situation, an initial roll direction boundary condition and an initial pitch direction boundary condition are set first (that is, the roll direction boundary condition and the pitch direction boundary condition at the time of rocket ignition are determined according to the hydrodynamic characteristics of the launch ship), and the roll minimum distance Ds1, the pitch minimum distance Ds2 and the comprehensive minimum distance are analyzed using the set roll direction boundary condition and the pitch direction boundary condition. If the minimum rolling distance Ds1, the minimum pitching distance Ds2 and the comprehensive minimum distance If the drift safety design requirements are met, the boundary conditions in the roll direction and the pitch direction are set to the required boundary conditions in the roll direction and the pitch direction, which can ensure that the support device and the rocket body will not collide. If one or more of the above does not meet the drift safety design requirements, it is necessary to adjust the set boundary conditions in the roll direction and the pitch direction to obtain the newly set boundary conditions in the roll direction and the pitch direction, and use the newly set boundary conditions in the roll direction and the pitch direction to analyze the minimum roll distance Ds1, the minimum pitch distance Ds2 and the comprehensive minimum distance

[0033] S3: Obtain the minimum rolling distance Ds1 according to the boundary conditions in the rolling direction, and analyze whether the minimum distance Ds1 meets the drift safety design requirements. If not, reduce the hydrodynamic parameters in the rolling direction of the launch ship; if satisfied, execute S7.

[0034] Furthermore, the sub-steps for obtaining the minimum rolling distance Ds1 according to the boundary conditions in the rolling direction are as follows:

[0035] S31: According to the boundary conditions in the roll direction, calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the first moment; according to the boundary conditions in the roll direction, calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the second moment; according to the boundary conditions in the roll direction, calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the third moment; wherein, the first moment represents the moment when the roll direction is in the horizontal position of the Y axis and the X axis is tilted to the left at 0; the second moment represents the moment when the roll direction is tilted to 0.5×A1 on the left side of the X axis; the third moment represents the moment when the roll direction is tilted to the left side of the X axis to the maximum inclination angle of the sway angle amplitude A1 in the boundary conditions of the roll direction.

[0036] Specifically, as an embodiment, the existing takeoff drift curve function calculation method is adopted or the boundary conditions in the roll direction and the first moment, the second moment or the third moment are input into a pre-trained model to obtain the corresponding takeoff drift curve function. The takeoff drift of the rocket is based on a six-degree-of-freedom full-scale rigid body dynamics model, taking into account the influence of wind interference and structural interference. For example, MATLAB software can be used for analysis, so it will not be repeated here.

[0037] like Figure 2As shown, the first moment is: θ1=0, the arrow body starts to move to the left; the second moment is: θ1=0.5×S1, the arrow body moves to the left; the third moment is: θ1=S1, the arrow body is located at the maximum shaking angle amplitude on the left side.

[0038] Furthermore, the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the first moment is f1(X1, Y1, Z1, t1); wherein X1 is the displacement of the rocket body mass center in the X-axis direction in the launch coordinate system at the first moment; Y1 is the displacement of the rocket body mass center in the Y-axis direction in the launch coordinate system at the first moment; Z1 is the displacement of the rocket body mass center in the Z-axis direction in the launch coordinate system at the first moment; and t1 is the time after the rocket body is ignited at the first moment.

[0039] The takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the second moment is f1'(X1', Y1', Z1', t1'); wherein X1' is the displacement of the rocket body mass center in the X-axis direction in the launch coordinate system at the second moment; Y1' is the displacement of the rocket body mass center in the Y-axis direction in the launch coordinate system at the second moment; Z1' is the displacement of the rocket body mass center in the Z-axis direction in the launch coordinate system at the second moment; and t1' is the time after the rocket body is ignited at the second moment.

[0040] The takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the third moment is f1”(X1”, Y1”, Z1”, t1”); wherein, X1” is the displacement of the rocket body mass center in the X-axis direction in the launch coordinate system at the third moment; Y1” is the displacement of the rocket body mass center in the Y-axis direction in the launch coordinate system at the third moment; Z1” is the displacement of the rocket body mass center in the Z-axis direction in the launch coordinate system at the third moment; t1” is the time after the rocket body is ignited at the third moment.

[0041] Specifically, the takeoff drift curve function f1(X1, Y1, Z1, t1) of the rocket body (rocket) ignition and takeoff process in the launch coordinate system when the roll direction is at the horizontal position of the Y axis and the X axis is tilted to the left at 0 is calculated according to the boundary conditions in the roll direction; the takeoff drift curve function f1'(X1', Y1', Z1', t1') of the rocket ignition and takeoff process in the launch coordinate system when the roll direction is tilted to 0.5×S1 on the left side of the X axis (rocket body) is calculated according to the boundary conditions in the roll direction; the takeoff drift curve function f1"(X1", Y1", Z1", t1") of the rocket ignition and takeoff process in the launch coordinate system when the roll direction is tilted to the sway angle amplitude A1 (i.e., the maximum inclination angle) in the boundary conditions in the roll direction is calculated according to the boundary conditions in the roll direction.

[0042] S32: Calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the first moment; calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the second moment; calculate the displacement f2" (X2", Y2", Z2", t2") of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the third moment, wherein the supporting point M is the contact point between the upper end of the left side of the supporting device and the arrow body.

[0043] Specifically, the displacement of the supporting point M corresponding to the first moment, the second moment and the third moment in the launch coordinate system can be obtained through the existing software set by the supporting device itself. For example: the anti-capsize arm of the supporting device is a lattice structure, the supporting point M is the contact point between the anti-capsize arm and the arrow body, the influence of wind load on the opening of the anti-capsize arm is ignored, and only the opening speed of the anti-capsize arm under different working conditions is considered during the rolling and pitching of the anti-capsize arm. The analysis can be performed by using software such as Adams, so it will not be repeated here.

[0044] Furthermore, the displacement of the supporting point M in the launch coordinate system during the opening process of the supporting device corresponding to the roll direction at the first moment is f2(X2, Y2, Z2, t2); wherein X2 is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the first moment; Y2 is the displacement of the supporting point M of the supporting device in the Y-axis direction in the launch coordinate system after the rocket body is ignited at the first moment; Z2 is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the first moment; and t2 is the time after the rocket body is ignited at the first moment.

[0045] The displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the second moment is f2'(X2', Y2', Z2', t2'); wherein X2' is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the second moment; Y2' is the displacement of the supporting point M of the supporting device in the Y-axis direction in the launch coordinate system after the rocket body is ignited at the second moment; Z2' is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the second moment; and t2' is the time after the rocket body is ignited at the second moment.

[0046] The displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the third moment is f2”(X2”, Y2”, Z2”, t2”); wherein, X2” is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the third moment; Y2” is the displacement of the supporting point M of the supporting device in the Y-axis direction in the launch coordinate system after the rocket body is ignited at the third moment; Z2” is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the third moment; t2” is the time after the rocket body is ignited at the third moment.

[0047] S33: Calculate the first distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the first moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the second distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the second moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the third distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the third moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; take the minimum value of the first distance, the second distance and the third distance as the minimum roll distance Ds1.

[0048] Specifically, according to the calculation results of three moments (i.e., the first moment, the second moment, and the third moment), the relationship between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process is determined, and the minimum roll distance Ds1 between the two in the launch coordinate system is calculated. The minimum roll distance Ds1 is analyzed using the drift safety design requirements. If the minimum roll distance Ds1 does not meet the drift safety design requirements, the hydrodynamic parameters of the launch ship in the roll direction are reduced; if the minimum roll distance Ds1 meets the drift safety design requirements, S7 is executed.

[0049] Among them, the takeoff drift of the rocket is based on the six-degree-of-freedom full-volume rigid body dynamics model, taking into account the influence of wind interference and structural interference. The anti-rollover arm of the supporting device is a lattice structure, and the influence of wind load on the opening of the anti-rollover arm is ignored. Only the opening speed of the anti-rollover arm under different working conditions is considered during the roll and pitch of the ship. The opening speed of the anti-rollover arm under different working conditions is calculated through simulation. Adams and other software can be used for analysis, and the roll and pitch conditions are calculated separately for comparison with the takeoff drift curve function.

[0050] S4: Obtain the minimum pitch distance Ds2 according to the boundary conditions in the pitch direction, and analyze whether the minimum pitch distance Ds2 meets the drift safety design requirements. If not, reduce the hydrodynamic parameters in the pitch direction of the launch ship; if satisfied, execute S7.

[0051] Furthermore, the sub-steps for obtaining the minimum pitch distance Ds2 according to the boundary conditions in the pitch direction are as follows:

[0052] S41: According to the boundary conditions in the pitch direction, the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fourth moment is calculated; according to the boundary conditions in the pitch direction, the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fifth moment is calculated; according to the boundary conditions in the pitch direction, the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the sixth moment is calculated; according to the boundary conditions in the pitch direction, the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the seventh moment is calculated; wherein, the fourth moment represents that the pitch angle of the rocket body in the pitch direction is The fifth moment represents the moment when the pitch angle of the arrow body is 0° and the time when the center of mass of the arrow body moves upward along the X-axis is 0s; the fifth moment represents the moment when the pitch angle of the arrow body is 0° and the time when the center of mass of the arrow body moves upward along the X-axis is 0s; the fifth moment represents the moment when the pitch angle of the arrow body is 0° and the time when the center of mass of the arrow body moves upward along the X-axis is 0s; the fifth moment represents the moment when the pitch angle of the arrow body is 0° and the time when the center of mass of the arrow body moves upward along the X-axis is 0s; the fifth moment represents the moment when the pitch angle of the arrow body is 0° and the time when the center of mass of the arrow body reaches the lowest point along the X-axis is 0.75×T2.

[0053] Specifically, Figure 3 As shown, the fourth moment is: θ2=0, the arrow body is to the left; the fifth moment is: θ2=A2, the arrow body is at the leftmost side; the sixth moment is: θ2=0, the arrow body is to the right; the seventh moment is: θ2=A2, the arrow body is at the rightmost side.

[0054] Specifically, as an embodiment, the corresponding takeoff drift curve function can be obtained by adopting the existing takeoff drift curve function calculation method or inputting the boundary conditions in the pitch direction and the fourth moment, the fifth moment, the sixth moment or the seventh moment into a pre-trained model, so it will not be repeated here.

[0055] Furthermore, the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fourth moment is f3(X3, Y3, Z3, t3); wherein X3 is the displacement of the rocket body mass center in the X-axis direction in the launch coordinate system at the fourth moment; Y3 is the displacement of the rocket body mass center in the Y-axis direction in the launch coordinate system at the fourth moment; Z3 is the displacement of the rocket body mass center in the Z-axis direction in the launch coordinate system at the fourth moment; and t3 is the time after the rocket body is ignited at the fourth moment.

[0056] The takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fifth moment is f3'(X3', Y3', Z3', t3'); wherein, X3' is the displacement of the rocket body mass center in the X-axis direction in the launch coordinate system at the fifth moment; Y3' is the displacement of the rocket body mass center in the Y-axis direction in the launch coordinate system at the fifth moment; Z3' is the displacement of the rocket body mass center in the Z-axis direction in the launch coordinate system at the fifth moment; t3' is the time after the rocket body is ignited at the fifth moment.

[0057] The takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the sixth moment is f3”(X3”, Y3”, Z3”, t3”); wherein, X3” is the displacement of the rocket body mass center in the X-axis direction in the launch coordinate system at the sixth moment; Y3” is the displacement of the rocket body mass center in the Y-axis direction in the launch coordinate system at the sixth moment; Z3” is the displacement of the rocket body mass center in the Z-axis direction in the launch coordinate system at the sixth moment; t3” is the time after the rocket body is ignited at the sixth moment.

[0058] The takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the seventh moment is f3"'(X3"', Y3"', Z3"', t3"'; wherein, X3"' is the displacement of the rocket body mass center in the X-axis direction in the launch coordinate system at the seventh moment; Y3"' is the displacement of the rocket body mass center in the Y-axis direction in the launch coordinate system at the seventh moment; Z3"' is the displacement of the rocket body mass center in the Z-axis direction in the launch coordinate system at the seventh moment; t3"' is the time after the rocket body is ignited at the seventh moment.

[0059] Specifically, the fourth moment represents the moment when the pitch direction is at the horizontal position of the Z axis of the arrow body (that is, the pitch angle of the arrow body is 0°), and the center of mass of the arrow body moves upward along the X axis (that is, 0s); the fifth moment represents the moment when the pitch direction is at the sway angle amplitude A2 in the boundary condition of the pitch direction, and the center of mass of the arrow body reaches the highest point along the X axis (that is, 0.25×T2, T2 is the sway period in the boundary condition of the pitch direction); the sixth moment represents the moment when the pitch direction is at the horizontal position of the Z axis of the arrow body (that is, the pitch angle of the arrow body is 0°), and the center of mass of the arrow body moves downward along the X axis (that is, 0.5×T2); the seventh moment represents the moment when the pitch direction is at the pitch angle of the arrow body -A2, and the center of mass of the arrow body reaches the lowest point along the X axis (0.75×T2).

[0060] S42: Calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the fourth moment; calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the fifth moment; calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the sixth moment; calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the seventh moment.

[0061] Specifically, the displacement of the supporting point M corresponding to the fourth moment, the fifth moment, the sixth moment and the seventh moment in the launch coordinate system can be obtained through the existing software set in the supporting device itself.

[0062] Furthermore, the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the fourth moment is f4(X4, Y4, Z4, t4); wherein X4 is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the fourth moment; Y4 is the displacement of the supporting point M of the supporting device in the Y-axis direction in the launch coordinate system after the rocket body is ignited at the fourth moment; Z4 is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the fourth moment; and t4 is the time after the rocket body is ignited at the fourth moment.

[0063] The displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the fifth moment is f4'(X4', Y4', Z4', t4'); wherein, X4' is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the fifth moment; Y4' is the displacement of the supporting point M of the supporting device in the Y-axis direction in the launch coordinate system after the rocket body is ignited at the fifth moment; Z4' is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the fifth moment; and t4' is the time after the rocket body is ignited at the fifth moment.

[0064] The displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the sixth moment is f4”(X4”, Y4”, Z4”, t4”); wherein, X4” is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the sixth moment; Y4” is the displacement of the supporting point M of the supporting device in the Y-axis direction in the launch coordinate system after the rocket body is ignited at the sixth moment; Z4” is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the sixth moment; t4” is the time after the rocket body is ignited at the sixth moment.

[0065] The displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the seventh moment is f4"'(X4"', Y4"', Z4"', t4"'; wherein, X4"' is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the seventh moment; Y4"' is the displacement of the supporting point M of the supporting device in the Y-axis direction in the launch coordinate system after the rocket body is ignited at the seventh moment; Z4"' is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the seventh moment; t4"' is the time after the rocket body is ignited at the seventh moment.

[0066] S43: Calculate the fourth distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fourth moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the fifth distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fifth moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the sixth distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the sixth moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the seventh distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the seventh moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; take the minimum value among the fourth moment, the fifth moment, the sixth moment and the seventh moment as the minimum pitch distance Ds2, and determine the time ts2 when the minimum pitch distance Ds2 appears.

[0067] Specifically, according to the calculation results of four moments (i.e., the fourth moment, the fifth moment, the sixth moment, and the seventh moment), the relationship between the takeoff drift curve function of the rocket body ignition takeoff process in the launch coordinate system and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process is determined, and the minimum pitch distance Ds2 between the two in the launch coordinate system is determined. It is judged whether the minimum pitch distance Ds2 meets the drift safety design requirements. If not, the hydrodynamic parameters of the launch ship in the pitch direction are reduced.

[0068] S5: Calculate the take-off time tq of the rocket body after ignition based on the boundary conditions in the pitch direction.

[0069] Furthermore, the sub-steps for calculating the take-off time tq of the rocket body after ignition according to the boundary conditions in the pitch direction are as follows:

[0070] S51: Calculate the vertical acceleration a of the arrow body in the pitch direction according to the boundary conditions in the pitch direction ci , where the vertical acceleration a generated by the arrow body in the pitch direction is ciIncluding: the vertical acceleration a generated by the arrow body in the pitch direction at the fourth moment c1 , the vertical acceleration a generated by the arrow body in the pitch direction at the fifth moment c2 , the vertical acceleration a generated by the arrow body in the pitch direction at the sixth moment c3 and the vertical acceleration a of the arrow body in the pitch direction at the seventh moment c4 .

[0071] Furthermore, the vertical acceleration a generated by the arrow body in the pitch direction ci The expression is:

[0072]

[0073] Wherein, A2 is the sway angle amplitude in the boundary condition of the pitch direction; L3 is the vertical distance from the center of mass of the arrow body in the boundary condition of the pitch direction to the pitch direction; T2 is the sway period in the boundary condition of the pitch direction; t i is the time, i∈[1,4], t1 is the time from the rocket body ignition to take-off at the fourth moment, t2 is the time from the rocket body ignition to take-off at the fifth moment, t3 is the time from the rocket body ignition to take-off at the sixth moment, and t4 is the time from the rocket body ignition to take-off at the seventh moment.

[0074] S52: The vertical acceleration a of the arrow body is generated according to the pitch direction ci Calculate the take-off time tq of the rocket body after ignition.

[0075] Specifically, the vertical acceleration a generated by the arrow body in the pitch direction is ci The relationship between the take-off time tq of the rocket body after ignition is:

[0076] F=G·lsp·(1-e t / T )=(a ci +g0);

[0077] Among them, F represents thrust; G represents the mass flow rate of fuel; lsp represents specific impulse; t represents time, that is, take-off time tq; T is the burning time; e is the base of natural logarithm; g0 is the acceleration due to gravity.

[0078] S6: Based on the take-off time tq of the rocket body after ignition, the time lengthening of the rocket body ignition thrust-to-weight ratio balance caused by the vertical acceleration of the rocket body in the pitch direction is compensated to obtain the comprehensive minimum distance

[0079] Furthermore, according to the take-off time tq of the rocket body after ignition, the time lengthening of the rocket body ignition thrust-to-weight ratio balance caused by the vertical acceleration of the rocket body in the pitch direction is compensated to obtain the comprehensive minimum distance The sub-steps are as follows:

[0080] S61: The first compensated moment is obtained by subtracting the take-off time tq from the time from the ignition of the rocket body to the take-off at the first moment; the second compensated moment is obtained by subtracting the take-off time tq from the time from the ignition of the rocket body to the take-off at the second moment; the third compensated moment is obtained by subtracting the take-off time tq from the time from the ignition of the rocket body to the take-off at the third moment.

[0081] Specifically, in order to compensate for the longer time required for ignition of the rocket body and thrust-to-weight ratio equilibrium due to the vertical acceleration of the rocket body in the pitch direction, the time from rocket body ignition to takeoff corresponding to the three moments in step S31 (i.e., the first moment, the second moment, and the third moment) is subtracted from the takeoff time tq to obtain the compensated moments, which include: the first compensated moment, the second compensated moment, and the third compensated moment.

[0082] S62: According to the boundary conditions in the roll direction, calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the first compensation moment; according to the boundary conditions in the roll direction, calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the second compensation moment; according to the boundary conditions in the roll direction, calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the third compensation moment.

[0083] Specifically, the corresponding takeoff drift curve function can be obtained by adopting the existing takeoff drift curve function calculation method or inputting the boundary conditions in the pitch direction, and the first compensation moment, the second compensation moment or the third compensation moment into a pre-trained model, so it will not be repeated here.

[0084] Furthermore, at the first post-compensation moment, the takeoff drift curve function of the rocket body during ignition and takeoff in the launch coordinate system is: in, is the displacement of the center of mass of the arrow in the X-axis direction in the launch coordinate system at the first compensation time (i.e., after the first compensation time tq); is the displacement of the arrow body mass center in the Y-axis direction in the launch coordinate system at the first compensation moment; is the displacement of the arrow body mass center in the Z-axis direction in the launch coordinate system at the first compensation moment; It is the time after the rocket body is ignited at the first compensation moment.

[0085] The takeoff drift curve function of the rocket body ignition takeoff process in the launch coordinate system at the second compensation time is: in, is the displacement of the center of mass of the arrow in the X-axis direction in the launch coordinate system at the second compensation time (i.e., after the second compensation time tq); is the displacement of the arrow body mass center in the Y-axis direction in the launch coordinate system at the second compensation moment; is the displacement of the arrow body mass center in the Z-axis direction in the launch coordinate system at the second compensation moment; It is the time after the rocket body is ignited at the second post-compensation moment.

[0086] The takeoff drift curve function of the rocket body ignition takeoff process in the launch coordinate system at the third compensation time is: in, is the displacement of the center of mass of the arrow body in the X-axis direction in the launch coordinate system at the time after the third compensation (i.e., after the third compensation time tq); is the displacement of the arrow body mass center in the Y-axis direction in the launch coordinate system at the third compensation moment; is the displacement of the arrow body mass center in the Z-axis direction in the launch coordinate system at the third compensation moment; It is the time after the rocket body is ignited at the third compensation moment.

[0087] S63: Calculate the displacement of the supporting point M in the launch coordinate system during the opening process of the supporting device corresponding to the roll direction at the first compensation moment; calculate the displacement of the supporting point M in the launch coordinate system during the opening process of the supporting device corresponding to the roll direction at the second compensation moment; calculate the displacement of the supporting point M in the launch coordinate system during the opening process of the supporting device corresponding to the roll direction at the third compensation moment, wherein the supporting point M is the contact point between the upper end of the left side of the supporting device and the arrow body.

[0088] Specifically, the displacement of the supporting point M corresponding to the first compensation moment, the second compensation moment and the third compensation moment in the launch coordinate system can be obtained through the existing software set in the supporting device itself.

[0089] Furthermore, the displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the first compensation moment is: in, is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the first compensation moment (i.e., after the first compensation moment tq); is the displacement of the supporting point M of the supporting device in the Y-axis direction of the launch coordinate system after the rocket body is ignited at the first compensation moment; is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the first compensation moment; It is the time after the rocket body is ignited at the first compensation moment.

[0090] The displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the second compensation moment is: in, is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the second post-compensation moment; is the displacement of the supporting point M of the supporting device in the Y-axis direction of the launch coordinate system after the rocket body is ignited at the second post-compensation moment; is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the second post-compensation moment; It is the time after the rocket body is ignited at the second post-compensation moment.

[0091] The displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the third compensation moment is: in, is the displacement of the supporting point M of the supporting device in the X-axis direction of the launch coordinate system after the rocket body is ignited at the third post-compensation moment; is the displacement of the supporting point M of the supporting device in the Y-axis direction of the launch coordinate system after the rocket body is ignited at the third post-compensation moment; is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the third post-compensation moment; It is the time after the rocket body is ignited at the third compensation moment.

[0092] S64: Calculate the first compensated distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the first compensated moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the second compensated distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the second compensated moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the third compensated distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the third compensated moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; take the minimum value of the first compensated distance, the second compensated distance and the third compensated distance as the comprehensive minimum distance

[0093] Specifically, according to the calculation results of three moments (i.e., the first compensation moment, the second compensation moment, and the third compensation moment), the relationship between the takeoff drift curve function of the rocket body ignition takeoff process in the launch coordinate system and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process is determined, and the comprehensive minimum distance between the two in the launch coordinate system is calculated.

[0094] S7: Using drift safety design requirements for comprehensive minimum distance For analysis, if the comprehensive minimum distance If the drift safety design requirements are met, the takeoff drift calculation results match the launch ship hydrodynamic conditions, and the simulation ends; if the comprehensive minimum distance If the drift safety design requirements are not met, the hydrodynamic parameters of the launch ship in the roll or pitch direction shall be reduced.

[0095] Specifically, if the minimum rolling distance Ds1, the minimum pitching distance Ds2 and the comprehensive minimum distance If the drift safety design requirements are met, the takeoff drift calculation results match the launch ship hydrodynamic conditions, and the simulation ends.

[0096] Furthermore, the drift safety design requirements include at least: a first safety threshold, a second safety threshold and a third safety threshold; the first safety threshold is used to analyze whether the minimum roll distance Ds1 meets the drift safety design requirements. If the minimum roll distance Ds1 is greater than or equal to the first safety threshold, it is satisfied; if the minimum roll distance Ds1 is less than the first safety threshold, it is not satisfied; the second safety threshold is used to analyze whether the minimum pitch distance Ds2 meets the drift safety design requirements. If the minimum pitch distance Ds2 is greater than or equal to the second safety threshold, it is satisfied; if the minimum pitch distance Ds2 is less than the second safety threshold, it is not satisfied; the third safety threshold is used to analyze the comprehensive minimum distance Whether the drift safety design requirements are met, if the minimum distance is greater than or equal to the third safety threshold, then it is satisfied; if the comprehensive minimum distance If it is less than the third safety threshold, it is not satisfied.

[0097] Specifically, specific values ​​of the first safety threshold, the second safety threshold, and the third safety threshold are set according to actual conditions.

[0098] Furthermore, the third safety threshold is 50 mm.

[0099] The beneficial effects achieved by this application are as follows:

[0100] (1) The method for analyzing the takeoff drift of a rocket launched at sea based on hydrodynamic parameter identification of the present application is a method for calculating the takeoff drift of a rocket during the takeoff process of launching at sea based on the hydrodynamic parameter identification of the launch ship. The method can determine the hydrodynamic boundary conditions of the launch ship (for example: roll angle amplitude, pitch angle amplitude and sway period, etc.), thereby ensuring that the takeoff drift of the rocket meets the drift safety design requirements.

[0101] (2) The method for analyzing the takeoff drift of a rocket launched at sea based on hydrodynamic parameter identification of the present application establishes four-dimensional spatial coordinates (X, Y, Z, t), models the spatial motion and time relationship in the launch coordinate system, simplifies the model complexity by independent lateral and longitudinal analysis, and further simplifies the influence of the complex hydrodynamic characteristics of the launch ship on the modeling difficulty, thereby reducing the computational complexity. At the same time, the safety of the takeoff drift during the ignition and takeoff process of the rocket at different movement moments in the roll direction or pitch direction can be analyzed, and the maximum risk point of the takeoff drift in the rolling direction and pitch direction shaking cycle is found respectively. A comprehensive analysis is performed based on the hydrodynamic characteristics of these two moments and the laws of rocket motion, thereby ensuring that the calculation result of the takeoff offset encompasses the comprehensive motion influence of the launch ship.

[0102] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the scope of protection of the present application is intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application. Obviously, those skilled in the art may make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the protection scope of the present application and its equivalent technology, the present application is also intended to include these modifications and variations.

Claims

1. A method for analyzing the drift of rocket launch and takeoff at sea based on hydrodynamic parameter identification, characterized in that: The steps include: S1: The rocket body is placed on the launch ship, and a supporting device is arranged in the roll direction, and the supporting device is connected to the rocket body; the tail of the rocket body is taken as the coordinate origin, the vertical direction facing the sky is taken as the X-axis, the horizontal direction of the length of the supporting device at the time of rocket body ignition is taken as the Y-axis, and the Z-axis is determined according to the right-hand rule. The Z-axis is perpendicular to the length direction of the supporting device. A launch coordinate system is constructed according to the coordinate origin, the X-axis, the Y-axis and the Z-axis. A four-dimensional space coordinate (X, Y, Z, t) is constructed according to the launch coordinate system and the time relationship t; S2: Determine the boundary conditions in the roll direction and the pitch direction at the time of rocket body ignition according to the hydrodynamic characteristics of the launch ship; wherein the boundary conditions in the roll direction are: sinusoidal periodic shaking, the shaking angle amplitude is A1, the shaking period is T1, the distance between the bottom support position of the rocket body and the supporting device in the roll direction is L1, and the distance between the bottom support position of the rocket body and the shaking center is L2; ​​the boundary conditions in the pitch direction are: sinusoidal periodic shaking, the shaking angle amplitude is A2, the shaking period is T2, the vertical distance between the center of mass of the rocket body and the pitch direction is L3, and the horizontal distance between the center of mass of the rocket body and the shaking center is L4; S3: Obtain the minimum rolling distance Ds1 according to the boundary conditions in the rolling direction, and analyze whether the minimum rolling distance Ds1 meets the drift safety design requirements. If not, reduce the hydrodynamic parameters in the pitch direction of the launching ship; if satisfied, execute S7; S4: Obtain the minimum pitch distance Ds2 according to the boundary conditions in the pitch direction, and analyze whether the minimum pitch distance Ds2 meets the drift safety design requirements. If not, reduce the hydrodynamic parameters in the pitch direction of the launching ship; if satisfied, execute S7; S5: Calculate the take-off time tq of the rocket body after ignition according to the boundary conditions in the pitch direction; S6: Based on the take-off time tq of the rocket body after ignition, the time lengthening of the rocket body ignition thrust-to-weight ratio balance caused by the vertical acceleration of the rocket body in the pitch direction is compensated to obtain the comprehensive minimum distance S7: Using drift safety design requirements for comprehensive minimum distance For analysis, if the minimum distance If the drift safety design requirements are met, the takeoff drift calculation results match the launch ship hydrodynamic conditions, and the simulation ends; if the comprehensive minimum distance If the drift safety design requirements are not met, the hydrodynamic parameters of the launch ship in the roll or pitch direction shall be reduced.

2. The method for analyzing the drift of rocket launch and takeoff at sea based on hydrodynamic parameter identification according to claim 1 is characterized in that: The sub-steps for obtaining the minimum rolling distance Ds1 according to the boundary conditions in the rolling direction are as follows: S31: Calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the first moment according to the boundary conditions in the roll direction; calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the second moment according to the boundary conditions in the roll direction; calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the third moment according to the boundary conditions in the roll direction; wherein, the first moment represents the moment when the roll direction is at the horizontal position of the Y axis and the X axis is tilted to the left at 0; the second moment represents the moment when the roll direction is tilted to 0.5×A1 on the left side of the X axis; the third moment represents the moment when the roll direction is tilted to the left side of the X axis to the maximum inclination angle of the sway angle amplitude A1 in the boundary conditions of the roll direction; S32: Calculate the displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the first moment; calculate the displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the second moment; calculate the displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the third moment, wherein the support point M is the contact point between the upper end of the left side of the support device and the arrow body; S33: Calculate the first distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the first moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the second distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the second moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the third distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the third moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; take the minimum value of the first distance, the second distance and the third distance as the minimum roll distance Ds1.

3. The method for analyzing the drift of rocket launch and takeoff at sea based on hydrodynamic parameter identification according to claim 2 is characterized in that: The sub-steps for obtaining the minimum pitch distance Ds2 according to the boundary conditions in the pitch direction are as follows: S41: According to the boundary conditions in the pitch direction, the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fourth moment is calculated; according to the boundary conditions in the pitch direction, the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fifth moment is calculated; according to the boundary conditions in the pitch direction, the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the sixth moment is calculated; according to the boundary conditions in the pitch direction, the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the seventh moment is calculated; wherein, the fourth moment represents that the pitch angle of the rocket body in the pitch direction is 0°, the time when the center of mass of the arrow body moves upward along the X-axis is 0s; the fifth moment represents the moment when the pitch angle of the arrow body is the sway angle amplitude A2 in the boundary condition of the pitch direction, and the time when the center of mass of the arrow body reaches the highest point along the X-axis is 0.25×T2, and T2 is the sway period in the boundary condition of the pitch direction; the sixth moment represents the moment when the pitch angle of the arrow body is 0°, and the time when the center of mass of the arrow body moves downward along the X-axis is 0.5×T2; the seventh moment represents the moment when the pitch angle of the arrow body is -A2, and the time when the center of mass of the arrow body reaches the lowest point along the X-axis is 0.75×T2; S42: Calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the fourth moment; calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the fifth moment; calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the sixth moment; calculate the displacement of the supporting point M in the launch coordinate system during the opening of the supporting device corresponding to the roll direction at the seventh moment; wherein the supporting point M is the contact point between the upper end of the left side of the supporting device and the arrow body; S43: Calculate the fourth distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fourth moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the fifth distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the fifth moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the sixth distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the sixth moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the seventh distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the seventh moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; take the minimum value among the fourth moment, the fifth moment, the sixth moment and the seventh moment as the minimum pitch distance Ds2.

4. The method for analyzing the drift of rocket launch and takeoff at sea based on hydrodynamic parameter identification according to claim 3 is characterized in that: The sub-steps for calculating the take-off time tq of the rocket body after ignition according to the boundary conditions in the pitch direction are as follows: S51: Calculate the vertical acceleration a of the arrow body in the pitch direction according to the boundary conditions in the pitch direction ci , where the vertical acceleration a generated by the arrow body in the pitch direction is ci Including: the vertical acceleration a generated by the arrow body in the pitch direction at the fourth moment c1 , the vertical acceleration a generated by the arrow body in the pitch direction at the fifth moment c2 , the vertical acceleration a of the arrow body in the pitch direction at the sixth moment c3 and the vertical acceleration a of the arrow body in the pitch direction at the seventh moment c4 ; S52: The vertical acceleration a of the arrow body is generated according to the pitch direction ci Calculate the take-off time tq of the rocket body after ignition.

5. The method for analyzing the drift of rocket launch and takeoff at sea based on hydrodynamic parameter identification according to claim 4 is characterized in that: The vertical acceleration a of the rocket body in the pitch direction ci The expression is: Wherein, A2 is the sway angle amplitude in the boundary condition of the pitch direction; L3 is the vertical distance from the center of mass of the arrow body in the boundary condition of the pitch direction to the pitch direction; T2 is the sway period in the boundary condition of the pitch direction; t i is the time, i∈[1,4], t1 is the time from the rocket body ignition to take-off at the fourth moment, t2 is the time from the rocket body ignition to take-off at the fifth moment, t3 is the time from the rocket body ignition to take-off at the sixth moment, and t4 is the time from the rocket body ignition to take-off at the seventh moment.

6. The method for analyzing the drift of rocket launch and takeoff at sea based on hydrodynamic parameter identification according to claim 4 is characterized in that: According to the take-off time tq of the rocket body after ignition, the time lengthening of the rocket body ignition thrust-to-weight ratio balance caused by the vertical acceleration of the rocket body in the pitch direction is compensated to obtain the comprehensive minimum distance The sub-steps are as follows: S61: subtract the take-off time tq from the time from the rocket body ignition to take-off at the first moment to obtain a first compensated time; subtract the take-off time tq from the time from the rocket body ignition to take-off at the second moment to obtain a second compensated time; subtract the take-off time tq from the time from the rocket body ignition to take-off at the third moment to obtain a third compensated time; S62: Calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the first compensation time according to the boundary conditions in the roll direction; calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the second compensation time according to the boundary conditions in the roll direction; calculate the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the third compensation time according to the boundary conditions in the roll direction; S63: Calculate the displacement of the support point M in the launch coordinate system during the opening process of the support device corresponding to the roll direction at the first compensation moment; Calculate the displacement of the support point M in the launch coordinate system during the opening process of the support device corresponding to the roll direction at the second compensation moment; Calculate the displacement of the supporting point M in the launch coordinate system during the opening process of the supporting device corresponding to the roll direction at the third compensation time, wherein the supporting point M is the contact point between the upper end of the left side of the supporting device and the arrow body; S64: Calculate the first compensated distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the first compensated moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the second compensated distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the second compensated moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; calculate the third compensated distance between the takeoff drift curve function of the rocket body ignition and takeoff process in the launch coordinate system at the third compensated moment and the displacement of the support point M in the launch coordinate system during the corresponding support device opening process; take the minimum value of the first compensated distance, the second compensated distance and the third compensated distance as the comprehensive minimum distance 7. The method for analyzing the drift of rocket launch and takeoff at sea based on hydrodynamic parameter identification according to claim 6 is characterized in that: The takeoff drift curve function of the rocket body ignition takeoff process in the launch coordinate system at the first compensation time is: in, is the displacement of the center of mass of the arrow in the X-axis direction in the launch coordinate system at the first compensation moment; is the displacement of the arrow body mass center in the Y-axis direction in the launch coordinate system at the first compensation moment; is the displacement of the arrow body mass center in the Z-axis direction in the launch coordinate system at the first compensation moment; is the time after the rocket body is ignited at the first compensation moment; the takeoff drift curve function of the rocket body ignition takeoff process in the launch coordinate system at the second compensation moment is in, is the displacement of the center of mass of the arrow in the X-axis direction in the launch coordinate system at the second compensation moment; is the displacement of the arrow body mass center in the Y-axis direction in the launch coordinate system at the second compensation moment; is the displacement of the arrow body mass center in the Z-axis direction in the launch coordinate system at the second compensation moment; is the time after the rocket body is ignited at the second compensation time; the takeoff drift curve function of the rocket body ignition takeoff process in the launch coordinate system at the third compensation time is in, is the displacement of the center of mass of the arrow in the X-axis direction in the launch coordinate system at the third compensation moment; is the displacement of the arrow body mass center in the Y-axis direction in the launch coordinate system at the third compensation moment; is the displacement of the arrow body mass center in the Z-axis direction in the launch coordinate system at the third compensation moment; It is the time after the rocket body is ignited at the third compensation moment.

8. The method for analyzing the drift of rocket launch and takeoff at sea based on hydrodynamic parameter identification according to claim 6 is characterized in that: The displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the first compensation moment is: in, is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the first compensation moment; is the displacement of the supporting point M of the supporting device in the Y-axis direction of the launch coordinate system after the rocket body is ignited at the first compensation time; is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the first compensation moment; is the time after the rocket body is ignited at the first compensation moment; the displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the second compensation moment is in, is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the second post-compensation moment; is the displacement of the supporting point M of the supporting device in the Y-axis direction of the launch coordinate system after the rocket body is ignited at the second post-compensation moment; is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the second post-compensation moment; is the time after the rocket body is ignited at the second compensation moment; the displacement of the support point M in the launch coordinate system during the opening of the support device corresponding to the roll direction at the third compensation moment is in, is the displacement of the supporting point M of the supporting device in the X-axis direction in the launch coordinate system after the rocket body is ignited at the third post-compensation moment; is the displacement of the supporting point M of the supporting device in the Y-axis direction of the launch coordinate system after the rocket body is ignited at the third post-compensation moment; is the displacement of the supporting point M of the supporting device in the Z-axis direction in the launch coordinate system after the rocket body is ignited at the third post-compensation moment; It is the time after the rocket body is ignited at the third compensation moment.

9. The method for analyzing the drift of rocket launch and takeoff at sea based on hydrodynamic parameter identification according to claim 1 is characterized in that: The drift safety design requirements include at least: the first safety threshold, the second safety threshold and the third safety threshold; The first safety threshold is used to analyze whether the minimum rolling distance Ds1 meets the drift safety design requirements. If the minimum rolling distance Ds1 is greater than or equal to the first safety threshold, it meets the requirements; if the minimum rolling distance Ds1 is less than the first safety threshold, it does not meet the requirements; The second safety threshold is used to analyze whether the minimum pitch distance Ds2 meets the drift safety design requirement. If the minimum pitch distance Ds2 is greater than or equal to the second safety threshold, it meets the requirement; if the minimum pitch distance Ds2 is less than the second safety threshold, it does not meet the requirement; Analyzing the comprehensive minimum distance using the third safety threshold Whether the drift safety design requirements are met, if the minimum distance is greater than or equal to the third safety threshold, then it is satisfied; if the comprehensive minimum distance If it is less than the third safety threshold, it is not satisfied.

10. The method for analyzing the drift of rocket launch and takeoff at sea based on hydrodynamic parameter identification according to claim 9 is characterized in that: The third safety threshold is 50mm.

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