A method for calculating the minimum airdrop height of an airdrop system

Abstract

A method for calculating the minimum airdrop height of an airdrop system, relating to the field of computation, is disclosed. The method involves obtaining the airdrop trajectory of the airdrop system; establishing a displacement-time curve based on the trajectory; calculating the relationship between the resultant velocity and time, and the relationship between the attitude angle and time, respectively, based on these curves; and placing these curves into a computational coordinate system, where the horizontal axis represents the airdrop system's lost height, and the vertical axis represents the resultant velocity and attitude angle. The minimum airdrop height is defined as the minimum airdrop height corresponding to the point where the resultant velocity reaches its minimum value and the attitude angle fluctuates within a preset range. This method effectively avoids problems such as high airdrop altitude and long landing point drift while ensuring safe airdrop landing.

Description

Technical Field

[0001] This application relates to the field of computing, and more specifically, to a method for calculating the minimum airdrop height of an airdrop system. Background Technology

[0002] Currently, the airdrop altitude for airdrop systems is generally determined based on traditional experience or test drops, while also observing the landing altitude after the airdrop system's attitude and speed stabilize in the air. This method of determining the airdrop altitude has a relatively large margin of error. To ensure the landing safety of the airdrop system, a large altitude margin is often required, with the minimum airdrop altitude being the height lost after the airdrop system has fully stabilized. This results in the minimum airdrop altitude being set too high, leading to a longer drift time in the air and lower landing accuracy. Summary of the Invention

[0003] The purpose of this application is to provide a method for calculating the minimum airdrop height of an airdrop system, which can effectively avoid problems such as high airdrop height and long drift of the airdrop system's landing point while ensuring the safety of airdrop landing.

[0004] This application is implemented as follows:

[0005] This application provides a method for calculating the minimum airdrop height of an airdrop system, including the following steps:

[0006] Obtain airdrop trajectory data from the airdrop system;

[0007] Based on the airdrop trajectory data, establish the relationship curve between airdrop trajectory displacement and time in a three-dimensional coordinate system;

[0008] Calculate the relationship between the resultant velocity and time of the airdrop system and the relationship between the attitude angle and time based on the relationship curve between the displacement and time of the airdrop trajectory.

[0009] The curves showing the relationship between the combined velocity and time and the attitude angle and time of the airdrop system are placed in the calculation coordinate system. The horizontal axis of the calculation coordinate system is the airdrop system loss height, and the vertical axis is the combined velocity and attitude angle. After the combined velocity decreases to fluctuate around the minimum combined velocity and the attitude angle decreases to fluctuate within the preset range, the minimum value of the airdrop system loss height corresponding to the combined velocity decreasing to the minimum combined velocity and the attitude angle decreasing to the preset range in the calculation coordinate system is taken as the minimum airdrop height of the airdrop system.

[0010] In some optional implementations, when acquiring the airdrop trajectory data of the airdrop system, an airdrop coordinate system is established, with the point at which the airdrop system leaves the aircraft as the origin. The X-axis points in the direction of the aircraft's flight, the Y-axis is perpendicular to the X-axis according to the right-hand coordinate system and is located on the horizontal plane, and the Z-axis points upward to represent the altitude of the airdrop system. The displacement of the airdrop system along the X-axis and Z-axis of the airdrop coordinate system over time during the airdrop is acquired as the airdrop trajectory data.

[0011] In some optional implementations, when calculating and establishing the relationship curves between the resultant velocity and time and the attitude angle and time of the airdrop system based on the displacement versus time curve of the airdrop trajectory, the following formulas are used to calculate the relationship curves between the acceleration and time and the attitude angle and time of the airdrop system:

[0012]

[0013] In the formula, For the acceleration of the airdrop system, D t The aerodynamic forces acting on the airdrop system; M S x represents the total mass of the airdrop system. S The X-axis displacement of the airdrop system after it leaves the aircraft; Z-axis displacement. S denoted as Z-axis displacement of the airdrop system after it leaves the aircraft; g is gravitational acceleration; θ is the attitude angle of the airdrop system; t is the airdrop time, which is started from the moment the airdrop system leaves the aircraft.

[0014] Calculate the resultant velocity of the airdrop system versus time based on the acceleration-time curve of the airdrop system.

[0015] In some alternative implementations, the attitude angle decreases to fluctuate within a preset range, meaning the peaks or troughs of the attitude angle fluctuations are within 10 degrees.

[0016] The beneficial effects of this application are as follows: The method for calculating the minimum airdrop height of the airdrop system provided by this application includes the following steps: acquiring the airdrop trajectory data of the airdrop system; establishing the relationship curve between the airdrop trajectory displacement and time in a three-dimensional coordinate system based on the airdrop trajectory data; calculating the relationship curve between the resultant velocity and time and the relationship curve between the attitude angle and time of the airdrop system based on the relationship curve between displacement and time; placing the relationship curves between the resultant velocity and time and the relationship curves between the attitude angle and time of the airdrop system into a calculation coordinate system, where the horizontal axis of the calculation coordinate system is the airdrop system loss height, and the vertical axis is the resultant velocity and attitude angle. The minimum airdrop height is determined by taking the minimum airdrop height when the resultant velocity decreases to fluctuate around the minimum resultant velocity and the attitude angle decreases to fluctuate within a preset range, and then taking the minimum value between the airdrop system loss height corresponding to the minimum resultant velocity and the airdrop system loss height corresponding to the preset range in the calculation coordinate system. The method for calculating the minimum airdrop height of the airdrop system provided by this application can effectively avoid problems such as high airdrop height and far-distance drift of the airdrop system landing point while ensuring safe airdrop landing. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating the method for calculating the minimum airdrop height of the airdrop system provided in this application embodiment;

[0019] Figure 2 A schematic diagram illustrating the minimum airdrop height during airdrop in the airdrop system calculation method provided in this application embodiment;

[0020] Figure 3 The graphs showing the relationship between the combined velocity and the lost height of the airdrop system, and the relationship between the attitude angle and the lost height of the airdrop system, are provided in the method for calculating the minimum airdrop height of the airdrop system in the embodiments of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0022] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0023] The features and performance of the minimum airdrop height calculation method of the airdrop system of this application will be further described in detail below with reference to the embodiments.

[0024] like Figure 1 and Figure 2 As shown in the figure, this application embodiment provides a method for calculating the minimum airdrop height of an airdrop system, including the following steps:

[0025] Step 1: Obtain the airdrop trajectory data of the airdrop system. When obtaining the airdrop trajectory data of the airdrop system, establish an airdrop coordinate system with the point at which the airdrop system leaves the aircraft as the origin. The X-axis points in the direction of the aircraft's flight, the Y-axis is perpendicular to the X-axis according to the right-hand coordinate system and is located on the horizontal plane, and the Z-axis points upward to represent the altitude of the airdrop system. Obtain the displacement data of the airdrop system along the X-axis and Z-axis of the airdrop coordinate system over time as the airdrop trajectory data.

[0026] Step 2: Based on the airdrop trajectory data, establish the relationship curve between the airdrop trajectory displacement and time in a three-dimensional coordinate system;

[0027] Step 3: Calculate the relationship between the resultant velocity and time of the airdrop system and the relationship between the attitude angle and time based on the relationship curve of the airdrop trajectory displacement versus time;

[0028] Use the following formulas to calculate the acceleration versus time curve and the attitude angle versus time curve of the airdrop system:

[0029]

[0030] Where, For the acceleration of the airdrop system, D t The aerodynamic forces acting on the airdrop system; M S x represents the total mass of the airdrop system. S The X-axis displacement of the airdrop system after it leaves the aircraft; Z-axis displacement. S θ is the Z-axis displacement of the airdrop system after it leaves the aircraft; g is the gravitational acceleration; θ is the attitude angle of the airdrop system; t is the airdrop time, which is started from the moment the airdrop system leaves the aircraft.

[0031] Step 4: Place the curves showing the relationship between the combined velocity and time, and the curves showing the relationship between the attitude angle and time, of the airdrop system into a calculation coordinate system. The horizontal axis of the calculation coordinate system represents the airdrop system's lost altitude, and the vertical axis represents the combined velocity and attitude angle. The minimum airdrop altitude is determined by taking the minimum airdrop altitude as the value corresponding to the point where the combined velocity drops to its minimum and the attitude angle drops to the preset range, after the combined velocity fluctuates around the minimum combined velocity and the attitude angle fluctuates within the preset range. Here, "attitude angle fluctuating within the preset range" means that the peak or trough of the attitude angle drops to within 10 degrees.

[0032] The method for calculating the minimum airdrop height of the airdrop system provided in this application analyzes the motion process of the airdrop system after it leaves the airdrop carrier. Since the kinetic energy of the airdrop system is proportional to the square of the total velocity, the landing time of the airdrop system is determined by minimizing the resultant velocity. Simultaneously, after the airdrop system leaves the aircraft, the parachute straightens and inflates. During the parachute inflation process, the airdrop system oscillates. The axis of the airdrop system is defined as the line connecting the cargo center of the airdrop system to the aerodynamic center of the parachute, pointing towards the aerodynamic center of the parachute. The angle between the axis of the airdrop system and the vertical direction is the attitude angle of the airdrop system. An attitude angle of 0 indicates that the airdrop system is perpendicular to the ground. The analysis parameters are selected when the resultant velocity is at its minimum and the attitude angle fluctuation range stabilizes at 0 degrees. Therefore, by acquiring the airdrop trajectory data of the airdrop system, the relationship curve between the airdrop trajectory displacement and time is established in the three-dimensional coordinate system based on the airdrop trajectory data. Based on the relationship curve between the airdrop trajectory displacement and time, the relationship curves between the resultant velocity and time and the attitude angle and time of the airdrop system are calculated respectively. The earliest time after the resultant velocity reaches its minimum value and fluctuates around the minimum value and the attitude angle decreases to a fluctuation range of 10 degrees is determined as the judgment point. The vertical descent height of the airdrop system at the judgment point is the minimum airdrop height.

[0033] The method for calculating the minimum airdrop height of the airdrop system provided in this application can effectively reduce the problems of large errors and high minimum airdrop heights in traditional methods. It can effectively avoid problems such as high airdrop heights and long drift of the landing point of the delivery system while ensuring the safety of airdrop landing, and has high application value.

[0034] Airdrop trajectory data of a certain airdrop system is collected. The relationship curves between the resultant velocity and time, and between the attitude angle and time, are calculated using the minimum airdrop height calculation method for the airdrop system provided in the above embodiment. Then, the relationship curves between the resultant velocity and the airdrop system's lost height, and between the attitude angle and the airdrop system's lost height, are established as follows: Figure 3 As shown, the airdrop system's height loss is determined to be 300m when the combined velocity reaches its minimum value (point a in the figure), and 350m when the attitude angle drops to within 10 degrees of the peak of the fluctuation range (point b in the figure). The minimum value of 300m is taken as the minimum airdrop height of the airdrop system. The minimum airdrop height of the airdrop system determined by the prior art is 500m. It can be seen that the minimum airdrop height calculation method of the airdrop system provided by the application embodiment can limit the reduction of the minimum airdrop height of the airdrop system based on experimental data.

[0035] In this embodiment, the airdrop system is the same as the material delivery system.

[0036] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for calculating the minimum airdrop height of an airdrop system, characterized in that, Includes the following steps: Obtain airdrop trajectory data from the airdrop system; Based on the airdrop trajectory data, establish a curve showing the relationship between airdrop trajectory displacement and time in a three-dimensional coordinate system; Calculate the resultant velocity versus time and attitude angle versus time curves of the airdrop system based on the displacement versus time curve of the airdrop trajectory; The curves showing the relationship between the combined velocity and time and the relationship between the attitude angle and time of the airdrop system are placed in a calculation coordinate system. The horizontal axis of the calculation coordinate system represents the airdrop system's lost height, and the vertical axis represents the combined velocity and attitude angle. After the combined velocity decreases to fluctuate around the minimum combined velocity and the attitude angle decreases to fluctuate within a preset range, the minimum airdrop height of the airdrop system is taken as the minimum airdrop height of the airdrop system when the combined velocity decreases to the minimum combined velocity and the attitude angle decreases to the preset range.

2. The method for calculating the minimum airdrop height of the airdrop system according to claim 1, characterized in that, When acquiring the airdrop trajectory data of the airdrop system, an airdrop coordinate system is established, with the point at which the airdrop system leaves the aircraft as the origin. The X-axis points in the direction of the aircraft's flight, the Y-axis is perpendicular to the X-axis according to the right-hand coordinate system and is located on the horizontal plane, and the Z-axis points upward to represent the altitude of the airdrop system. The displacement of the airdrop system along the X-axis and Z-axis of the airdrop coordinate system over time during the airdrop is acquired as the airdrop trajectory data.

3. The method for calculating the minimum airdrop height of the airdrop system according to claim 1, characterized in that, When calculating and establishing the relationship curves between the resultant velocity and time, and the attitude angle and time, of the airdrop system based on the displacement versus time curve of the airdrop trajectory, the following formulas are used to calculate the relationship curves between the acceleration and time, and the attitude angle and time, of the airdrop system: ； ； In the formula, For the acceleration of the airdrop system, D t The aerodynamic forces acting on the airdrop system; M S The total mass of the airdrop system; x S This refers to the X-axis displacement of the airdrop system after it leaves the aircraft. Z S This refers to the Z-axis displacement of the airdrop system after it leaves the aircraft. g It is the acceleration due to gravity; θ The attitude angle of the airdrop system; t The airdrop time is counted from the moment the aircraft leaves the airdrop system. Calculate the resultant velocity of the airdrop system as a function of time based on the acceleration-time curve of the airdrop system.

4. The method for calculating the minimum airdrop height of the airdrop system according to claim 1, characterized in that, The attitude angle drops to within the preset range when the peak or trough of the attitude angle fluctuation is within 10 degrees.

Images