Method for testing rotating speed of muzzle projectile by using high-speed camera

Abstract

The invention belongs to a method for testing the rotating speed of a flying projectile in the field of non-sitting force guns, which comprises the following steps of: photographing and capturing the flying projectile by using a high-speed camera at a specified station on one side of a ballistic trajectory, recording the starting time and the ending time by using marks on the surface of the projectile, and calculating the average rotating speed of the projectile at a certain point when the projectile flies; the system is composed of an emplacement (1), a flying projectile (3) and a high-speed camera (2). According to the method, after an artillery on a gun position (1) shoots ammunition, a flying projectile (3) appears on a trajectory trajectory, a high-speed camera (2) shoots the movement condition of the projectile in a view field and stores the movement condition, and then the time when a marking line is located on the axis of a projectile shaft after the projectile enters the view field and before the projectile leaves the view field is checked and recorded as T0 and T1 respectively, according to the time interval from T0 to T1 of the projectile, the number of turns of the projectile rotating in the interval can be read, and according to the number of turns of the projectile rotating and the time, the flight rotating speed of the projectile can be obtained through calculation.

Description

Technical Field

[0001] A test method for testing the muzzle velocity of projectiles using a high-speed camera belongs to the field of ammunition performance testing technology. Specifically, it relates to the testing of the rotational velocity of projectiles in the field of recoilless rifles, and is particularly suitable for the accurate testing of the muzzle velocity of airburst fragmentation ammunition, providing key parameter support for the correction of ammunition airburst distance. Background Technology

[0002] For new types of air-bomb fragmentation munitions, precise positioning of the air-bomb distance is crucial. The projectile's rotational speed is a critical parameter for correcting the air-bomb's impact time, thus requiring testing of the air-bomb's rotational speed. Traditional methods include the scratch method, telemetry, radar method, and photographic method. The photographic method involves first calculating the distance using an object distance formula, then placing a film camera at a fixed position to photograph the flying projectile. After developing the photographs, the rotational speed is calculated using parameters such as the linear velocity of the film, the projectile's expected velocity within the photographed area, the distance between adjacent time markers, the time marker frequency, and the distance between two adjacent spirals on the test projectile's axis within the film. While this method can test the rotational speed, the testing techniques are not updated, the procedure is complex, and numerous parameters, including approximations, are used. For example, the projectile's expected velocity within the photographed area and the distance between adjacent time markers (typically 3mm-5mm) are estimates, increasing the systematic error in the test. Therefore, to address the above issues and reduce system testing errors while simplifying the testing procedure, the testing method was updated based on a high-speed camera (capturing more than 20,000 frames per second). A high-speed camera was positioned on one side of the ballistic trajectory line to test the projectile's rotational speed. This method is simple to operate; after recording the time at the projectile's marked points, the projectile's rotational speed can be calculated easily. Since the calculation only involves time parameters, the testing accuracy is relatively high. Summary of the Invention

[0003] Purpose of the invention

[0004] The purpose of this invention is to develop a reliable method for testing the rotational speed of projectiles, solving the problems of complex procedures and large systematic errors in existing testing methods. This invention provides a method for testing the muzzle rotational speed of projectiles based on a high-speed camera, which simplifies the testing process, reduces systematic errors, and improves testing accuracy and reliability.

[0005] Technical solution

[0006] The testing system of the present invention consists of a gun position (1), a flying projectile (3), and a high-speed camera (2). The method is to use the projectile (3) that appears on the trajectory line after the gun fires ammunition at the gun position (1), use the high-speed camera (2) to capture and store the movement of the projectile in the field of view, and then check the time when the marker line is located on the axis of the projectile after the projectile enters the field of view and before it leaves the field of view, which are recorded as T0 and T1 respectively. According to the time interval from T0 to T1, the number of revolutions of the projectile in the interval can be read out. Based on the number of revolutions of the projectile and the time, the flight speed of the projectile can be calculated.

[0007] By photographing and capturing the flying projectile at a designated position on one side of the ballistic trajectory, the start and end times are recorded using marks on the projectile's surface, and the average rotational speed of the projectile at a certain point during flight is calculated.

[0008] Beneficial effects

[0009] The testing process is simplified, eliminating the need for complex steps such as object distance formula calculation and film processing. Testing can be completed simply through video capture, parameter reading, and basic calculations, improving operational efficiency by more than 50%.

[0010] To reduce systematic errors, the calculation relies only on two measured parameters, "time difference (T1-T0)" and "number of rotations (n)", without any estimated parameters, and the systematic error is reduced to less than 1 / 3 of that of the traditional photographic method.

[0011] To improve testing accuracy, a high-speed camera is used, which can accurately capture the position of the marker line, with time recording accuracy down to the microsecond level, and high speed testing accuracy.

[0012] It is highly adaptable and can adjust the spacing, vertical distance of the camera, and number of equally divided marking lines according to different gun types and projectile sizes, making it suitable for testing all types of recoilless rifles and empty explosives. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the test system. Detailed Implementation

[0014] This invention provides a method for testing the rotational speed of projectiles in the field of recoilless rifles. Figure 1In the schematic diagram of the test system shown, first, fix the gun position (1), determine the trajectory line of the projectile, and determine the average rotation speed at a distance a from the gun muzzle. Along the trajectory line, erect marker poles at points A and B from the gun muzzle. Set up a high-speed camera (2) at point C, which is perpendicular to the midpoint of line AB. Adjust the vertical distance b between the camera and line AB and the focal length so that the field of view of the high-speed camera covers the marker poles at points A and B. After adjusting the parameters such as the number of frames, resolution and exposure time of the high-speed camera, place the simulated projectile with the marked line at the center of the field of view so that the marked line is facing the high-speed camera. Adjust the focus aperture of the high-speed camera so that the marked line on the projectile is clearly displayed.

[0015] Launch the projectile (3), capture and save the video of the projectile from entering the field of view to leaving the field of view, and use high-speed camera software to read the projectile's entry and exit data. When the projectile enters the field of view and the marking line on it is directly facing the high-speed camera, the time point is recorded as T0. When the projectile leaves the field of view and the marking line on it is directly facing the high-speed camera, the time point is recorded as T1. The unit of T0 and T1 is "second". Record the number of revolutions n of the projectile during the time period from T0 to T1. If the projectile is divided into 6 equal parts along the circumference, and the number of marking lines the projectile passes through during the time period from T0 to T1 is 8, then the number of revolutions the projectile makes is 7 / 6 revolutions.

[0016] The number of revolutions per unit time can be calculated using n / (T1-T0). Multiplying the number of revolutions per unit time by 60 gives the rotational speed of the projectile per minute.

[0017] The formula for calculating the muzzle velocity of a projectile is as follows:

[0018] N = 60n / (T1-T0).

Claims

1. A method for testing the muzzle velocity of a projectile using a high-speed camera, characterized in that, The test system includes a gun position (1), a projectile (3), and a high-speed camera (2). After the gun at the gun position (1) fires the ammunition, a projectile (3) appears on the trajectory line. The high-speed camera (2) captures and stores the movement of the projectile in the field of view. Then, the time when the marker line is located on the projectile axis after the projectile enters the field of view and before it leaves the field of view is observed and recorded as T0 and T1 respectively. Based on the time interval from T0 to T1, the number of revolutions of the projectile in that interval can be read. Based on the number of revolutions and the time, the flight speed of the projectile is calculated.

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