Method for calculating minimum air-drop height of air-drop system

Abstract

The invention discloses an air-drop system minimum air-drop height calculation method, and relates to the field of calculation. The method for calculating the minimum air-drop height of the air-drop system comprises the following steps: acquiring an air-drop track of the air-drop system; establishing a relation curve of air-drop trajectory displacement and time according to the air-drop trajectory; according to the relation curve of the displacement and the time, a relation curve of the resultant velocity and the time and a relation curve of the attitude angle and the time of the air-drop system are calculated respectively; the relation curve of the resultant velocity and the time and the relation curve of the attitude angle and the time of the air-drop system are put into a calculation coordinate system, the abscissa of the calculation coordinate system is the loss height of the air-drop system, and the ordinate of the calculation coordinate system is the resultant velocity and the attitude angle; and calculating the minimum loss height of the airdrop system corresponding to the coordinate system as the minimum airdrop height of the airdrop system when the resultant speed drops to the minimum value and the attitude angle drops to the preset range. The method for calculating the minimum air-drop height of the air-drop system can effectively avoid the problems that the air-drop height is high and the landing point of the air-drop system drifts far under the condition that the air-drop landing safety is guaranteed.

Description

Technical Field

[0001] The present application relates to the field of computing, and in particular to a method for calculating a minimum airdrop height of an airdrop system. Background Art

[0002] At present, the airdrop height of the airdrop system is generally determined based on traditional experience or airdrop test methods, and the landing height of the airdrop system after the airdrop attitude and speed are stabilized is observed as a basis for judgment. This method of determining the airdrop height has a large error. In order to ensure the landing safety of the airdrop system, it is often necessary to reserve a large height margin, and the loss height after the airdrop system is completely stable is used as the minimum airdrop height, resulting in the minimum airdrop height being set too high, the airdrop system drifting in the air for a long time, and the landing point accuracy is low. 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 landing point of the airdrop system while ensuring the safety of airdrop landing.

[0004] This application is implemented as follows:

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

[0006] Get the airdrop trajectory data of the airdrop system;

[0007] According to the airdrop trajectory data, a relationship curve between airdrop trajectory displacement and time is established in a three-dimensional coordinate system;

[0008] According to the relationship curve between airdrop trajectory displacement and time, the relationship curve between total velocity and time and the relationship curve between attitude angle and time of the airdrop system are calculated respectively;

[0009] The relationship curve between the total speed and time of the airdrop system and the relationship curve between the attitude angle and time are placed in the calculation coordinate system. The horizontal coordinate of the calculation coordinate system is the loss height of the airdrop system, and the vertical coordinate is the total speed and the attitude angle. After the total speed drops to fluctuate around the minimum total speed and the attitude angle drops to fluctuate within the preset range, the minimum value of the loss height of the airdrop system corresponding to the time when the total speed drops to the minimum total speed and the attitude angle drops to the preset range in the calculation coordinate system is taken as the minimum airdrop height of the airdrop system.

[0010] In some optional implementation schemes, when acquiring the airdrop trajectory data of the airdrop system, an airdrop coordinate system is established, with the point when the airdrop system leaves the aircraft as the coordinate origin, the X-axis pointing in the flight direction of the aircraft, the Y-axis being perpendicular to the X-axis and located in the horizontal plane according to the right-hand coordinate system, and the Z-axis pointing upwards to represent the altitude of the airdrop system, and 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 implementation schemes, when respectively calculating and establishing the relationship curve between the total velocity and time and the relationship curve between the attitude angle and time of the airdrop system according to the relationship curve between the airdrop trajectory displacement and time, the following formula is used to calculate the relationship curve between the acceleration and time and the relationship curve between the attitude angle and time of the airdrop system:

[0012]

[0013] In the formula, is the acceleration of the airdrop system, D t M is the aerodynamic force on the airdrop system; S is the total mass of the airdrop system; x S is the X-axis displacement of the airdrop system after leaving the aircraft; Z S is the Z-axis displacement of the airdrop system after it leaves the aircraft; g is the acceleration of gravity; θ is the attitude angle of the airdrop system; t is the airdrop time, which starts from the time the airdrop system leaves the aircraft;

[0014] The relationship curve between the total velocity and time of the airdrop system is calculated based on the relationship curve between the acceleration and time of the airdrop system.

[0015] In some optional embodiments, the attitude angle drops to fluctuate within a preset range, which means that the peak or trough of the attitude angle fluctuation is within 10 degrees.

[0016] The beneficial effect of the present application is that the method for calculating the minimum airdrop height of the airdrop system provided by the present application comprises the following steps: obtaining the airdrop trajectory data of the airdrop system; establishing the relationship curve between the displacement of the airdrop trajectory and time in the three-dimensional coordinate system according to the airdrop trajectory data; calculating the relationship curve between the total velocity and time and the relationship curve between the attitude angle and time of the airdrop system according to the relationship curve between the displacement and time; putting the relationship curve between the total velocity and time and the relationship curve between the attitude angle and time of the airdrop system into the calculation coordinate system, the horizontal coordinate of the calculation coordinate system is the loss height of the airdrop system, the vertical coordinate is the total velocity and the attitude angle, after the total velocity drops to fluctuate around the minimum total velocity and the attitude angle drops to fluctuate within a preset range, the minimum value of the loss height of the airdrop system corresponding to the calculation coordinate system when the total velocity drops to the minimum total velocity and the attitude angle drops to the preset range is taken as the minimum airdrop height of the airdrop system. The method for calculating the minimum airdrop height of the airdrop system provided by the present application can effectively avoid the problems of high airdrop height and long drift of the landing point of the airdrop system while ensuring the safety of airdrop landing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of a flow chart of a method for calculating the minimum airdrop height of an airdrop system provided in an embodiment of the present application;

[0019] Figure 2 A schematic diagram of the minimum airdrop height of the airdrop system during airdrop in the method for calculating the minimum airdrop height of the airdrop system provided in an embodiment of the present application;

[0020] Figure 3 The method for calculating the minimum airdrop height of the airdrop system provided in the embodiment of the present application includes a curve showing the relationship between the speed and the airdrop system loss height, and a curve showing the relationship between the attitude angle and the airdrop system loss height. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0022] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0023] The features and performance of the method for calculating the minimum airdrop height of the airdrop system of the present application are further described in detail below in conjunction with the embodiments.

[0024] like Figure 1 and Figure 2 As shown, the embodiment of the present application provides a method for calculating the minimum airdrop height of an airdrop system, comprising 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 when the airdrop system leaves the aircraft as the coordinate origin, the X-axis points to the flight direction of the aircraft, the Y-axis is perpendicular to the X-axis according to the right-hand coordinate system and is located in the horizontal plane, and the Z-axis upwards represents the altitude of the airdrop system. The displacement data of the airdrop system along the X-axis and Z-axis of the airdrop coordinate system that changes with time during airdrop is obtained as the airdrop trajectory data.

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

[0027] Step 3: Calculate the relationship curve between the total velocity and time and the relationship curve between the attitude angle and time of the airdrop system according to the relationship curve between the airdrop trajectory displacement and time;

[0028] Use the following formula to calculate the relationship between the acceleration and time and the relationship between the attitude angle and time of the airdrop system:

[0029]

[0030] In the formula, is the acceleration of the airdrop system, D t M is the aerodynamic force on the airdrop system; S is the total mass of the airdrop system; x S is the X-axis displacement of the airdrop system after leaving the aircraft; Z S is the Z-axis displacement of the airdrop system after it leaves the aircraft; g is the acceleration of gravity; θ is the attitude angle of the airdrop system; t is the airdrop time, which starts from the time the airdrop system leaves the aircraft.

[0031] Step 4: Place the relationship curve between the total velocity and time of the airdrop system and the relationship curve between the attitude angle and time into the calculation coordinate system. The horizontal coordinate of the calculation coordinate system is the airdrop system loss height, and the vertical coordinate is the total velocity and attitude angle. When the total velocity drops to fluctuate around the minimum total velocity and the attitude angle drops to fluctuate within a preset range, the minimum value of the airdrop system loss height corresponding to the total velocity drops to the minimum total velocity and the attitude angle drops to the preset range in the calculation coordinate system is taken as the minimum airdrop height of the airdrop system. Among them, the attitude angle drops to fluctuate within the preset range means that the attitude angle drops to the point where the peak or trough of the attitude angle is within 10 degrees.

[0032] The method for calculating the minimum airdrop height of an airdrop system provided in an embodiment of the present application analyzes the movement process of the airdrop system after the airdrop system leaves the airdrop carrier as the starting point. Since the kinetic energy of the airdrop system is proportional to the square of the total speed, the landing time of the airdrop system is determined by the minimum combined speed. At the same time, the parachute is straightened and inflated after the airdrop system leaves the aircraft. During the inflation of the parachute, the airdrop system swings. The line connecting the cargo center of the airdrop system to the aerodynamic center of the parachute and pointing to the aerodynamic center of the parachute is defined as the axis of the airdrop system. The angle between the axis of the airdrop system and the vertical direction is the attitude angle of the airdrop system. If the attitude angle is 0, it means that the airdrop system is perpendicular to the ground. , that is, the minimum combined velocity and the attitude angle fluctuation range tend to be stable and then become 0 degrees as the analysis parameters; therefore, by obtaining 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 according to the airdrop trajectory data, and the relationship curve between the combined velocity and time and the relationship curve between the attitude angle and time of the airdrop system are calculated respectively according to the relationship curve between the airdrop trajectory displacement and time, and the earliest time after the combined velocity reaches the minimum value and fluctuates around the minimum value and the attitude angle drops to a fluctuation range of 10 degrees is determined as the judgment point, and the vertical landing height of the airdrop system at the judgment point is selected as the minimum airdrop height.

[0033] The method for calculating the minimum airdrop height of the airdrop system provided in the embodiment of the present application can effectively reduce the problems of large errors and high minimum airdrop height in determining the minimum airdrop height by traditional methods, and effectively avoid the problems of high airdrop height and long drift of the landing point of the drop system while ensuring the safety of airdrop landing, and has high use value.

[0034] Collect the airdrop trajectory data of a certain airdrop system, calculate the airdrop trajectory data according to the airdrop system minimum airdrop height calculation method provided in the above embodiment to obtain the relationship curve between the combined speed and time and the relationship curve between the attitude angle and time, and then establish the relationship curve between the combined speed and the airdrop system loss height and the relationship curve between the attitude angle and the airdrop system loss height. Figure 3 As shown, through analysis, it is determined that the airdrop system loss height when the combined speed reaches the minimum value (point a in the figure) is 300m, and the airdrop system loss height when the attitude angle drops to the peak of the fluctuation range within 10 degrees (point b in the figure) is 350m. The minimum value of 300m is taken as the minimum airdrop height of the airdrop system, and the minimum airdrop height of the airdrop system determined according to the prior art is 500m. It can be seen that the minimum airdrop height calculation method for the airdrop system provided by the application embodiment can limit the reduction of the minimum airdrop height of the airdrop system based on the test data.

[0035] The airdrop system in this embodiment is a delivery system.

[0036] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

Claims

1. A method for calculating the minimum airdrop height of an airdrop system, characterized in that: The following steps are involved: Get the airdrop trajectory data of the airdrop system; Establishing a relationship curve between airdrop trajectory displacement and time in a three-dimensional coordinate system according to the airdrop trajectory data; According to the relationship curve between the airdrop trajectory displacement and time, a relationship curve between the total velocity and time and a relationship curve between the attitude angle and time of the airdrop system are calculated; The relationship curve between the combined speed and time and the relationship curve between the attitude angle and time of the airdrop system are placed in a calculation coordinate system, wherein the horizontal coordinate of the calculation coordinate system is the airdrop system loss height, and the vertical coordinate is the combined speed and the attitude angle. After the combined speed drops to fluctuate above and below the minimum combined speed and the attitude angle drops to fluctuate within a preset range, the minimum value of the airdrop system loss height corresponding to the combined speed drops to the minimum combined speed and the attitude angle drops to the preset range in the calculation coordinate system is taken as the minimum airdrop height of the airdrop system.

2. The method for calculating the minimum airdrop height of an airdrop system according to claim 1, characterized in that: When obtaining the airdrop trajectory data of the airdrop system, an airdrop coordinate system is established, with the point when the airdrop system leaves the aircraft as the coordinate origin, the X-axis pointing to the flight direction of the aircraft, the Y-axis being perpendicular to the X-axis according to the right-hand coordinate system and located in the horizontal plane, and the Z-axis pointing upward to indicate the altitude of the airdrop system, and the displacement of the airdrop system along the X-axis and Z-axis of the airdrop coordinate system as time changes during airdrop is obtained as the airdrop trajectory data.

3. The method for calculating the minimum airdrop height of an airdrop system according to claim 1, characterized in that: When respectively calculating and establishing the relationship curve between the total velocity and time and the relationship curve between the attitude angle and time of the airdrop system according to the relationship curve between the airdrop trajectory displacement and time, the following formula is used to calculate the relationship curve between the acceleration and time and the relationship curve between the attitude angle and time of the airdrop system: In the formula, is the acceleration of the airdrop system, D t M is the aerodynamic force on the airdrop system; S is the total mass of the airdrop system; x S is the X-axis displacement of the airdrop system after leaving the aircraft; Z S is the Z-axis displacement of the airdrop system after it leaves the aircraft; g is the acceleration of gravity; θ is the attitude angle of the airdrop system; t is the airdrop time, which starts from the time the airdrop system leaves the aircraft; The relationship curve between the total velocity and time of the airdrop system is calculated according to the relationship curve between the acceleration and time of the airdrop system.

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

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