阅读说明：本技术 一种可实现子弹目标探测的头盔系统 (Helmet system capable of realizing bullet target detection ) 是由 张丽敏 樊子予 迟洋滨 骞昊 闫锋 于 2020-11-09 设计创作，主要内容包括：本发明提出了一种可实现子弹目标探测的头盔系统,包括六个探测电极、放大调理电路以及FPGA处理模块,显著特征在于,分布于头盔上的六个电极来感应子弹经过时电荷量的变化,放大调理电路将电极上感应的电荷量转换成电压量输出至FPGA处理模块,FPGA处理模块在水平和垂直方向分别检测子弹运动波形的特征信息来实现子弹运动速度及方向测量。其显著优势在于,探测方法只需依靠时间差信息,无需精确测定幅值,具有算法简单、易实现、精度高、低成本等显著优点；且该装置的测速范围大,可以弥补声学无法探测消音武器、亚音速弹丸的缺陷；探测装置体积小巧,集成在头盔上便于单兵佩戴；对天气、视野等没有苛刻的要求,适用于恶劣天气或黑暗环境。(The invention provides a helmet system capable of realizing bullet target detection, which comprises six detection electrodes, an amplification conditioning circuit and an FPGA processing module and is characterized in that the six electrodes distributed on a helmet are used for sensing the change of the electric charge quantity of a bullet passing through, the amplification conditioning circuit converts the electric charge quantity sensed on the electrodes into the voltage quantity and outputs the voltage quantity to the FPGA processing module, and the FPGA processing module is used for respectively detecting the characteristic information of the bullet motion waveform in the horizontal direction and the vertical direction to realize the measurement of the bullet motion speed and the bullet motion direction. The method has the obvious advantages that the detection method only needs to rely on time difference information and does not need to accurately measure the amplitude, and the method has the obvious advantages of simple algorithm, easy realization, high precision, low cost and the like; the device is large in speed measurement range, and can make up for the defects that acoustics cannot detect noise-reduction weapons and subsonic projectiles; the detection device is small in size and integrated on a helmet, so that an individual soldier can conveniently wear the detection device; has no strict requirements on weather, visual field and the like, and is suitable for severe weather or dark environment.)

1. A helmet system capable of realizing bullet target detection comprises six detection electrodes, an amplification conditioning circuit and an FPGA processing module, and is characterized in that the six electrodes are distributed on a helmet in A, B two groups, if a three-dimensional rectangular coordinate system is established by taking the hemispherical center of the helmet as an original point and taking the bottom surface as a xoy plane, 3 horizontal electrodes of the group A are positioned in the middle of the helmet and placed in parallel to the xoy plane, 3 vertical electrodes of the group B are placed in a xoz plane, the electrode connecting lines of the same plane are isosceles right triangles, and the six metal detection electrodes simultaneously sense the change of the charge amount when a bullet passes through and are respectively connected to the amplification conditioning circuit; the amplifying and conditioning circuit comprises a charge sensor and an amplifying and filtering circuit, and converts the charge quantity induced on the electrode into a voltage quantity to be output to the FPGA processing module; the FPGA processing module collects and measures A, B output voltage waveforms amplified and conditioned by two groups of electrodes, the horizontal and vertical component velocity and direction of bullet motion are calculated through the time difference between the zero crossing point and the peak valley value of the voltage waveforms, and finally the composite velocity and direction can be calculated.

2. The system of claim 1, wherein the helmet has a hemispherical shape with a radius of 0.1m to 0.2 m.

3. The system of claim 1, wherein the distance between the group B of 3 vertical electrodes and the y-axis is about the radius of a hemisphere of the helmet, i.e. the size of the oblique side of the connecting line of the group B of 3 vertical electrodes is about the diameter of the hemisphere of the helmet; the plane of the group A of 3 horizontal electrodes is positioned in the middle of the helmet, and the distance between the group A of electrodes and the z axis is about the radius of a hemisphere of the helmet.

4. The helmet system of claim 1, wherein the six electrodes are made of metal materials such as copper, aluminum, tin, etc., have a shape of circle, square, etc., and have a size of 1cm²-5cm²。

5. The helmet system for detecting bullet targets according to claim 1, wherein the measurement of the moving speed and direction of the bullet target comprises the following steps:

1) a, B two groups of six metal detection electrodes are arranged on the helmet, each group of 3 electrodes are positioned on the same plane, the connecting line is an isosceles right triangle, if a three-dimensional rectangular coordinate system is established by taking the hemisphere center of the helmet as the original point and the bottom surface as the xoy plane, the 3 horizontal electrodes of the group A are positioned in the middle of the helmet and are placed parallel to the xoy plane, and the distance between the electrodes and the z axis is d_a(ii) a The 3 vertical electrodes of group B were placed at a distance d from the y-axis in the plane xoz_b；

2) The six metal electrodes are respectively connected to an amplifying and conditioning circuit and are connected with an FPGA processing module;

3) a, B the electrodes of the two groups respectively use their electrode planes as xoy plane to establish independent rectangular coordinate system, and the processing module respectively measures the zero crossing point t of the output waveform amplified and conditioned by the two groups of electrodes of the corresponding charge sensor A, B_i1、t_i2、t_i3Wherein i ═ a, b;

4) the bullet motion component velocity directions of A, B two groups of electrode planes, namely the included angle theta between the projection of the motion path and the x-axis of each coordinate system can be respectively calculated according to the zero crossing point and the time difference_iWherein i ═ a, b:

(t_i1＜t_i2，-π/2≤θ_i＜π/2；t_i1＞t_i2，π/2≤θ_i＜3π/2) (1)

5) magnitude v of the velocity component of movement of the bullet_iCan be moved in the direction of motion theta_iZero crossing point t_i1、t_i2、t_i3To obtain, wherein i ═ a, b:

6) transforming the coordinates to a helmet coordinate system, the vector of the velocity component of the bullet in each plane can be obtained as follows:

the total speed is:

the projection of the velocity direction on the xoy plane of the helmet coordinate system forms an angle with the x-axis:

the projection onto the plane of helmet coordinate system xoz makes an angle with the x-axis:

Technical Field

The invention relates to a helmet system capable of realizing bullet target detection, in particular to a helmet system capable of realizing bullet movement speed and direction measurement through induction charge quantity change.

Background

In modern military operations, protecting soldiers from security in the battlefield has become one of the most important things. When the bullet detector is used for dealing with fire with enemy troops or encountering a vogue, the source of the gunshot and the direction of the shooter of the enemy can be quickly and accurately determined, so that the bullet detector can timely respond to danger and provide valuable reference information for quickly searching the shelter to counterattack, and the development of the bullet detector is significant in the military field.

At present, fire sensing systems are developed in many countries, and the fire sensing systems can be mainly divided into detection mechanisms such as acoustics, radar, infrared optics and the like according to the principle, but the implementation methods have defects of different degrees. The acoustic microphone array bullet detection system is the most developed bullet detection system at present, and the direction of a shooter is determined based on detonation waves and Mach waves generated by a sub-ejection chamber, but the acoustic microphone array bullet detection system cannot be used for identifying situations such as subsonic projectiles, noise reduction weapons and noisy battlefield environments, and is not suitable for detecting multi-firepower concurrency situations; the bullet detection system based on the radar detects the position of a bullet through high-frequency scanning of the active radar to form a bullet path, so that the bullet detection system has the defects of complex equipment, high power consumption, huge equipment and the like, cannot be miniaturized and is convenient for an individual soldier to carry; and infrared optics bullet detection system detects through the infrared information that sends when the son pops out the thorax, and it is very high to look at the visual field requirement, should not be used to bad weather such as rain and fog, and does not resist sheltering from.

An electric field-based bullet detection system detects based on an electric field generated in a bullet flying process, related researches of the method are few at present, only rough detection of a bullet motion angle can be realized in existing researches, the precision is 30 degrees, and accurate measurement cannot be realized. Therefore, a bullet target detection method needs to be provided, which can overcome the influence of environmental sound, is portable, is not influenced by light and shielding, and can realize accurate bullet direction detection.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a helmet system for detecting the movement speed and direction of a bullet by sensing the change of electric charge.

In order to achieve the purpose of the invention, the technical scheme provided by the invention is as follows:

a helmet system capable of realizing bullet target detection comprises six detection electrodes, an amplification conditioning circuit and an FPGA processing module, and is characterized in that the six electrodes are distributed on a helmet in A, B two groups, if a three-dimensional rectangular coordinate system is established by taking the hemispherical center of the helmet as an original point and taking the bottom surface as a xoy plane, 3 horizontal electrodes of the group A are positioned in the middle of the helmet and placed in parallel to the xoy plane, 3 vertical electrodes of the group B are placed in a xoz plane, the electrode connecting lines of the same plane are isosceles right triangles, and the six metal detection electrodes simultaneously sense the change of the charge amount when a bullet passes through and are respectively connected to the amplification conditioning circuit; the amplifying and conditioning circuit comprises a charge sensor and an amplifying and filtering circuit, and converts the charge quantity induced on the electrode into a voltage quantity to be output to the FPGA processing module; the FPGA processing module collects and measures A, B output voltage waveforms amplified and conditioned by two groups of electrodes, the horizontal and vertical component velocity and direction of bullet motion are calculated through the time difference between the zero crossing point and the peak valley value of the voltage waveforms, and finally the composite velocity and direction can be calculated.

Further, the helmet is hemispherical, and the radius is 0.1m-0.2 m.

Furthermore, the distance between the three vertical electrodes in the group B and the y axis is about the radius of the helmet hemisphere, namely the size of the oblique side of the connecting line of the 3 vertical electrodes in the group B is about the diameter of the helmet hemisphere; the plane of the group A of 3 horizontal electrodes is positioned in the middle of the helmet, and the distance between the group A of electrodes and the z axis is about the radius of a hemisphere of the helmet.

Furthermore, the six electrodes are made of metal materials such as copper, aluminum and tin, and have the same material, size and area, and the shape of circle, square and the like with the size of 1cm²-5cm²。

A helmet system capable of realizing bullet target detection is characterized in that the moving speed and direction of a bullet target are measured, and the helmet system specifically comprises the following steps:

1) the helmet is provided with A, B groups of six metal detection electrodes, wherein each group of 3 electrodes are positioned on the same plane and the connecting line is an isosceles right triangle. If the semi-sphere center of the helmet is taken as the originAnd (3) establishing a three-dimensional rectangular coordinate system for the xoy plane on the bottom surface, wherein the 3 horizontal electrodes of the group A are positioned in the middle of the helmet and are placed in parallel to the xoy plane, and the distance between the electrodes and the z axis is d_a(ii) a The 3 vertical electrodes of group B were placed at a distance d from the y-axis in the plane xoz_b；

2) The six metal electrodes are respectively connected to an amplifying and conditioning circuit and are connected with an FPGA processing module;

3) a, B the electrodes of the two groups respectively use their electrode planes as xoy plane to establish independent rectangular coordinate system, and the processing module respectively measures the zero crossing point t of the output waveform amplified and conditioned by the two groups of electrodes of the corresponding charge sensor A, B_i1、t_i2、t_i3Wherein i ═ a, b;

4) the bullet motion component velocity directions of A, B two groups of electrode planes, namely the included angle theta between the projection of the motion path and the x-axis of each coordinate system can be respectively calculated according to the zero crossing point and the time difference_iWherein i ═ a, b:

(t_i1＜t_i2，-π/2≤θ_i＜π/2；t_i1＞t_i2，π/2≤θ_i＜3π/2) (1)

5) magnitude v of the velocity component of movement of the bullet_iCan be moved in the direction of motion theta_iZero crossing point t_i1、t_i2、t_i3To obtain, wherein i ═ a, b:

6) transforming the coordinates to a helmet coordinate system, the vector of the velocity component of the bullet in each plane can be obtained as follows:

the total speed is:

the projection of the velocity direction on the xoy plane of the helmet coordinate system forms an angle with the x-axis:

the projection onto the plane of helmet coordinate system xoz makes an angle with the x-axis:

the method is characterized in that six electrodes integrated on a helmet are used for sensing charge changes, characteristic information of bullet motion waveforms is detected in the horizontal direction and the vertical direction respectively to achieve measurement of bullet motion speed and direction, only time difference information is needed, amplitude is not needed to be measured accurately, the method has the remarkable advantages of being simple in algorithm, easy to achieve, high in precision, low in cost and the like, the speed measurement range of the device is large, the defect that an acoustic weapon and subsonic projectiles cannot be detected can be overcome, the detection device is small in size, is integrated on the helmet, convenient to wear by an individual soldier, free of harsh requirements on weather, visual fields and the like, and is suitable for severe weather or dark environments.

Drawings

Fig. 1 is a model diagram of a helmet system.

Fig. 2 is a schematic diagram of the movement path and projection of the bullet in space, a) the movement path in helmet coordinates, b) the projection of the movement path in xoy plane, and c) the projection of the movement path in xoz plane.

Fig. 3 shows A, B output waveforms after amplified conditioning on two sets of electrodes when a bullet passes through, a) output waveforms of group a of 3 electrodes, and B) output waveforms of group B of 3 electrodes.

Detailed Description

To further elaborate the effect of the present invention, assume that the relevant parameters of a bullet are: q₀＝10^-9C, v is 1000m/s, and the present invention will be described below with reference to this specific bullet motion speed and direction detection example, as follows:

1) a, B two groups of six copper detection electrodes are arranged on a hemispherical helmet with the radius of 0.1m, the electrodes are square, the side length is 0.01m, 3 electrodes in each group are positioned on the same plane, the connecting line is an isosceles right triangle, if a three-dimensional rectangular coordinate system is established by taking the hemispherical center of the helmet as the original point and the bottom surface as the xoy plane, 3 horizontal electrodes in the group A are positioned in the middle of the helmet and are placed in parallel to the xoy plane, and the distance d between the electrodes and the z axis is_aIs 0.07 m; the 3 vertical electrodes of group B were placed at a distance d from the y-axis in the plane xoz_bIs 0.1m, as shown in figure 1;

2) six copper electrodes are respectively connected to an amplifying and conditioning circuit and are connected with an FPGA processing module, and an input capacitor C of a charge sensor_iAre all 10 pF;

3) under the helmet coordinate system, the straight line of the bullet motion path is assumed as follows:

the projection of the velocity direction on the xoy plane of the helmet coordinate system forms an angle theta with the x-axis₁68.199 DEG, minute velocity v_a873.589 m/s; the projection of the velocity direction on the plane of the helmet coordinate system xoz forms an angle theta with the x-axis₂56.310 DEG, minute velocity v_b584.898 m/s; the schematic diagram of the moving path of the bullet in the space is shown in figure 2;

matlab is adopted to simulate output signals of electrodes of the observation surface under the path, and A, B two groups of three are obtainedThe output waveforms on the electrodes are shown in FIG. 3, and the zero-crossing points t of the output signals on two groups of 3 electrodes are respectively read A, B_a1、t_a2、t_a3And t_b1、t_b2、t_b3The following can be obtained:

t_a1＝-0.39ms，t_a2＝-0.346ms，t_a3＝-0.45ms；t_b1＝-0.394ms，t_b2＝-0.35ms，t_b3＝-0.586ms；

4) further, the corresponding θ is calculated according to the formula (1)_a、θ_bThe following can be obtained:

θ_a＝-67.0679°，θ_b＝-79.4390°；

5) further, the corresponding projection velocity | v is calculated according to the equations (2), (3) and (4)_a|、|v_bI, |, can be:

|v_a|＝876.645m/s，|v_b|＝589.092m/s；

6) further, according to the formula (5), the resultant velocity | v | ═ 1003.126 m/s; according to the formulas (6) and (7), the included angle between the projection of the speed direction on the xoy plane of the helmet coordinate system and the x axis can be calculated as follows: theta₁67.932 °, the projection onto the plane of the helmet coordinate system xoz forms an angle with the x-axis: theta₂＝54.704°。

The positioning result is consistent with the set result, and the feasibility of detecting the motion speed and the direction of the bailing bomb is demonstrated.