CN111521884A - A kind of human body electrostatic field quantitative non-contact detection device and detection method - Google Patents

Abstract

The invention provides a quantitative non-contact detection device and a detection method for a human body electrostatic field, wherein a test area is formed by the quantitative non-contact detection device for the human body electrostatic field arranged on a ceiling, a binocular vision camera is combined, a person to be detected enters the test area, the binocular vision camera measures the distance of the object to be detected through video data and estimates the actual height and the limb state of the object to be detected, meanwhile, the quantitative non-contact detection device for the human body electrostatic field detects and combines binocular vision information to determine the self electrostatic level of the person to be detected, and the quantitative non-contact detection device for the human body electrostatic field comprises a grounding shielding cover, a shielding layer, a motor, a first coil, a second coil, an insulating disc, a metal fan, a capacitor, a synchronous control module. The system can automatically complete non-contact and remote detection of the electrostatic voltage level of the human body target in the detected area, can be linked with access control equipment in an electrostatic sensitive place, and has the advantages of accurate detection and high automation level.

Description

A kind of human body electrostatic field quantitative non-contact detection device and detection method

technical field

The invention belongs to the technical field of electrostatic detection and protection in electromagnetic compatibility, and in particular relates to a quantitative non-contact detection device and a detection method for the electrostatic field of a human body.

Background technique

In units such as gasoline stations, flour mills, paint factories, etc., the air contains high concentrations of flammable and explosive components. These occasions are extremely sensitive to electrostatic protection. When a worker enters the work area with electrostatic charge and a partial discharge occurs during the work, it is likely to detonate the explosive components in the air and cause a vicious safety accident. At present, the detection of human body electrostatic level is still in the stage of close-up detection of instruments, which has the shortcomings of short detection distance and low automation level. The market needs an automated, non-contact human body static detection method, which is placed at the entrance of a safe workplace sensitive to static electricity and linked with access control equipment, so as to effectively ensure the safety of production sites and staff.

SUMMARY OF THE INVENTION

The invention provides a quantitative non-contact detection device and detection method for the electrostatic field of a human body, and solves the problems of the existing close-up electrostatic detection instruments, such as short detection distance, need to contact with the human body, manual operation, and low automation level.

The invention provides a quantitative non-contact detection device for human electrostatic field, comprising a grounding shield, a shielding layer, a motor, a first coil, a second coil, an insulating disc, a metal fan, a capacitor, a synchronous control module, and an amplifying bandpass module , the shielding layer separates the grounding shield into an upper layer and a lower layer, the motor is arranged on the upper layer, the first coil, the second coil, the insulating disc and the metal fan are arranged on the lower layer, and the shaft of the motor passes through the shielding layer and the metal fan connection, the shielding layer, the first coil, and the metal fan are all grounded, the insulating disc is fixedly arranged and laid on it with a number of copper foils. The shape and area are the same, the second coil is connected to the copper foil of the insulating disc, and a capacitor is connected between the first coil and the second coil as the input of the amplifying band-pass module, and the amplifying band-pass module outputs the electrostatic field variable. The synchronous control module drives the motor and controls the speed of the motor.

The present invention also provides a quantitative non-contact detection method for the electrostatic field of a human body, the method is as follows:

S1. Install the human body electrostatic field quantitative non-contact detection device on the ceiling to form a test area, and divide the test area into different positions F={f ₀ , f ₁ , f ₂ ..... f _n },

S2. The quantitative non-contact detection device for the electrostatic field of the human body is calibrated at different positions, and the coefficient vectors M={a ₀ , a ₁ , a ₂ ..... a _n } and N={b ₀ , corresponding to each position are obtained. b ₁ ,b ₂ .....b _n },

S3. The person to be tested stands at a certain position J in the test area, and the height of the discharge tip of the human body to be measured is measured by the binocular camera as h', and the sine wave electrostatic field transmission value is output through the quantitative non-contact detection device of the human electrostatic field. The value is A',

Roughly calculate the electrostatic voltage of the human body to be measured according to the formula U'=a _J ·A'+b _J (1), where a _J is the coefficient in the coefficient vector M corresponding to the position J, and b _J is the coefficient vector corresponding to the position J coefficients in N,

精确计算待测人体的静电电压，其中，k_j为换算因子，H为天花板的高度，h为校准模特的身高。Then according to the formula

Accurately calculate the electrostatic voltage of the human body to be measured, where k _j is the conversion factor, H is the height of the ceiling, and h is the height of the calibration model.

Further, the method for calibrating the quantitative non-contact detection device of human electrostatic field is as follows:

S1. Use an aluminized ball with a diameter of R _b as the equivalent charged model of the human body, place the metal ball at the plane position f(x ₀ , y ₀ ), and fix the aluminized ball at a distance L from the ceiling through an insulating bracket,

S2. Use a high-voltage generator to generate a voltage U ₀ and charge the aluminized ball to generate an electrostatic field. At this time, the value of the electrostatic field actually conducted to the detection module is E ₀ .

S3. Gradient adjustment U ₀ and recording of the electrostatic field transmission value A output by the amplifying band-pass module, establishing a linear fit for the relationship between U ₀ and A, and obtaining the formula U ₀ =a ₀ ·A+b ₀ (4 ),

S4. Place the aluminized balls at different plane positions in the test area, repeat steps S2 and S3 to obtain the coefficients corresponding to the different plane positions, that is, the coefficient vector M={a ₀ , a ₁ , a ₂ ...... a _n } and N={b ₀ , b ₁ , b ₂ . . . b _n }.

标准模特变换不同位置，重复上述计算过程，可获得换算因子向量K＝{k₀,k₁,k₂…..k_n}。Further, the conversion factor k _j is obtained by the following method: looking for a person with a height of h as a calibration model, making him wear a nylon fabric and stepping on a plastic pad, and then apply an electrostatic voltage U ₀ to his body and keep standing normally. The pose is placed under the ceiling at the position _F = _{ f ₀ , f ₁ , _{f 2} ...... The electrostatic voltage U ₀ ′ of the calibration model collected by the quantitative non-contact detection device, and then the conversion factor k _j between the standard model and the aluminized ball at this position is calculated,

The standard model is transformed into different positions, and the above calculation process is repeated to obtain a conversion factor vector K={k ₀ , k ₁ , k ₂ .....k _n }.

Beneficial effects of the present invention:

The quantitative non-contact detection device and detection method of the human body electrostatic field of this patent can automatically complete the non-contact and long-distance detection of the electrostatic voltage level of the human body target in the measured area, and can be linked with the access control equipment in the electrostatic sensitive place to automatically detect the entry and exit. The electrostatic level of human body has the advantages of accurate detection and high automation level.

Description of drawings

1 is a schematic diagram of the overall structure of a quantitative non-contact detection device for human electrostatic field according to the present invention;

Fig. 2 is the circuit schematic diagram of the quantitative non-contact detection device of human electrostatic field according to the present invention;

Fig. 3 is the circuit diagram of the band-pass amplifying module of the quantitative non-contact detection device of human electrostatic field of the present invention;

Fig. 4 is the programmable varistor circuit diagram of the quantitative non-contact detection device of human electrostatic field according to the present invention;

Fig. 5 is the principle diagram of the human body electrostatic detection method of the present invention,

FIG. 6 is a schematic diagram of the binocular vision camera ranging of the present invention.

Attached notes:

1. Ground shield, 2. Shielding layer, 3. Motor, 4. First coil, 5. Second coil, 6. Insulating disc, 7. Metal fan, 8. Capacitor, 9. Synchronous control module, 10, Amplified bandpass module, 11, copper foil, 12, grounding point.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, and should not be construed as limiting the specific protection scope of the present invention.

Example

Referring to FIG. 1 , this embodiment provides a quantitative non-contact detection device for human electrostatic field, including a ground shield 1, a shield 2, a motor 3, a first coil 4, a second coil 5, an insulating disc 6, and a metal fan 7. Capacitor 8, synchronous control module 9, amplifying bandpass module 10, the shielding layer 2 separates the ground shielding cover 1 into an upper layer and a lower layer, the motor 3 is arranged on the upper layer, the first coil 4, the second coil 5, the insulating circle The disk 6 and the metal fan 7 are arranged on the lower layer. The shaft of the motor 3 is connected to the metal fan 7 through the shielding layer 2. The shielding layer 2, the first coil 4 and the metal fan 7 are all grounded, as shown in FIG. 1 . ground point 12. The insulating disc 6 is fixedly arranged and a number of copper foils 11 are laid thereon. The number, shape and area of the copper foils 11 are the same as the number, shape and area of the blades of the metal fan 7 . There are four copper foils in this embodiment. , the metal fan 7 also has four blades, the second coil 5 is connected to the copper foil 11 of the insulating disk 6, and the capacitor 8 is connected between the first coil 4 and the second coil 5 as the amplification bandpass module 10 The input of the amplifying bandpass module 10 outputs the sine wave electrostatic field transmission value, and the synchronous control module 9 drives the motor 3 and controls the speed of the motor 3 .

The working process of the detection device is as follows: the synchronous control module 9 drives the motor 3 to act, and the rotating shaft of the motor 3 drives the metal fan 7 to rotate. The electric field lines of the electrostatic field of the human body standing on the ground (indicated by the arrow at the bottom of Figure 1) are blocked by the blades of the metal fan 7, so that the potential on the copper foil 11 is at a low potential. When the blades of the metal fan 7 and the copper foil 11 are completely staggered , the copper foil 11 is completely exposed to the surface electrostatic field, and its own potential also reaches a peak value. With the continuous rotation of the metal fan 7, the potential on the copper foil 11 changes periodically.

In the present invention, a first coil 4 and a second coil 5 are arranged in the grounding shield 1, wherein the second coil 5 is connected with the four copper foils 11, and the first coil 4 is grounded. During the operation of the metal fan 7 , the potential difference between the two coils presents a sine wave signal whose amplitude is linearly related to the field strength of the electrostatic field on the ground, and its frequency is determined by the speed of the motor 3 . This embodiment uses a synchronous control module 9 based on a microcontroller design. On the one hand, the rotational speed of the motor 3 is accurately controlled, and on the other hand, the programmable operational amplifier in the amplifying bandpass module 10 is adjusted to realize the rotational speed of the motor 3 and the center of the bandpass filter. Frequency synchronization, thereby filtering possible interference signals and ensuring the accuracy of the signal. Figure 2 is the circuit block diagram of the quantitative non-contact detection device for human electrostatic field. The synchronous control module 9 adopts STM32F103 single-chip microcomputer, and the band-pass amplifying module adopts the band-pass amplifying circuit shown in Figure 3. The STM32F103 single-chip microcomputer realizes the band-pass amplifying module 10 and the Metal fan 7 speed synchronization. On the one hand, the STM32F103 microcontroller control circuit selects the center frequency fc of the band-pass amplifying circuit, and then controls the output resistances corresponding to R ₁ , R ₂ and R _B resistances through the IO port. After the configuration of the band-pass amplifier circuit is completed, the STM32F103 uses the PWM signal to drive the motor 3 to rotate, and uses the encoder to monitor the speed of the metal fan 7 in real time. The duty cycle of the PWM signal is adjusted in real time by comparing the actual rotational speed of the metal fan 7 , so that the rotational speed of the metal fan 7 is precisely synchronized with the band-pass amplifier circuit.

The band-pass amplifying circuit of this embodiment is a band-pass amplifying filter circuit with adjustable frequency band designed based on the low-noise operational amplifier AD797, and the center frequency and upper and lower limit frequencies of the pass-band are f _c , f _up and f _down , respectively. On the premise that the quality factor Q of the circuit, the center frequency gain K _PB and the filter capacitor C (C ₁ =C ₂ =C, unit F) are pre-determined, the resistance values R ₁ and R ₂ in the circuit are respectively as follows: shown:

Among them, K _PB needs to satisfy the restriction condition K _PB <2Q ² , and the calculation formula of _RB under this boundary condition is as follows:

According to the actual situation, the speed of the motor 3 should be kept at 80-120Hz, and the Q value should be kept high so as to avoid the interference of the mains. Therefore, in this embodiment, the center frequency of the band-pass amplifying circuit is set as f _c =80-120 Hz, Q = 10, K _PB =100. And the circuit preset capacitance C=0.1uF. According to formula 1-3, it can be calculated that the resistance value variation ranges of the three resistors are R ₁ =R _B =133-200Ω, R ₂ =26.4-105kΩ. In order to meet the above varistor requirements, the present embodiment adopts the programmable varistor circuit based on the X9315 chip as shown in FIG. 4 . The X9315 chip can output a variable resistance of 10-100kΩ, and the control port is controlled by the STM32F103 microcontroller to realize the change of the output resistance. In this embodiment, the output resistance range required by R ₁ / _RB is completed by connecting a 200Ω resistor in parallel with the output end of the X9315, and R ₂ can be directly led to the output resistance end.

As shown in Figure 5, the quantitative non-contact detection device for human electrostatic field in this embodiment can be installed on the ceiling, deployed at the entrance of oil and gas, flour and other safety production sites, linked with the access control system, and combined with binocular vision cameras to detect the entry of personnel in real time. The static electricity level of the human body, if the static electricity level of the measured object itself exceeds the safety threshold, the access control system will be blocked and an alarm will be triggered, and the measured object will be prompted to perform the electrostatic discharge process. The specific method of human body electrostatic field detection is as follows:

S1. Install the human body electrostatic field quantitative non-contact detection device on the ceiling to form a test area, and divide the test area into different positions F={f ₀ , f ₁ , f ₂ ..... f _n },

S2. The quantitative non-contact detection device for the electrostatic field of the human body is calibrated at different positions, and the coefficient vectors M={a ₀ , a ₁ , a ₂ ..... a _n } and N={b ₀ , corresponding to each position are obtained. b ₁ ,b ₂ .....b _n },

S3. The person to be tested stands at a certain position J in the test area, as shown in Figure 6, the height of the discharge tip of the human body to be measured is measured by the binocular vision camera as h', and the sine wave is output through the quantitative non-contact detection device of the human body electrostatic field Electrostatic field transmission value, the amplitude is A',

Roughly calculate the electrostatic voltage of the human body to be measured according to the formula U'=a _J ·A'+b _J (1), where a _J is the coefficient in the coefficient vector M corresponding to the position J, and b _J is the coefficient vector corresponding to the position J coefficients in N,

精确计算待测人体的静电电压，其中，k_j为换算因子，H为天花板的高度，h为校准模特的身高。所述双目视觉摄像头测算目标的立体坐标位置(x，y)，同时利用所拍摄的图像建立MobileNet模型获得拍摄对象的肢体姿态图，计算其真正的放电尖端的高度。Then according to the formula

Accurately calculate the electrostatic voltage of the human body to be measured, where k _j is the conversion factor, H is the height of the ceiling, and h is the height of the calibration model. The binocular vision camera measures the three-dimensional coordinate position (x, y) of the target, and at the same time uses the captured images to establish a MobileNet model to obtain the limb posture map of the captured object, and calculates the height of its real discharge tip.

Step S2 of the above detection method includes calibrating the quantitative non-contact detection device for the electrostatic field of the human body, and the specific calibration method is as follows:

S1. Use an aluminized ball with a diameter of R _b as the equivalent charged model of the human body, place the aluminized ball at the plane position f(x ₀ , y ₀ ), and fix the aluminized ball at a distance L from the ceiling through an insulating bracket,

S2. Use a high-voltage generator to generate a voltage U ₀ and charge the aluminized ball to generate an electrostatic field. At this time, the value of the electrostatic field actually conducted to the detection module is E ₀ .

S3. Gradient adjustment U ₀ and recording of the electrostatic field transmission value A output by the amplifying band-pass module, establishing a linear fit for the relationship between U ₀ and A, and obtaining the formula U ₀ =a ₀ ·A+b ₀ (4 ),

S4. Place the aluminized balls at different plane positions in the test area, repeat steps S2 and S3 to obtain the coefficients corresponding to the different plane positions, that is, the coefficient vector M={a ₀ , a ₁ , a ₂ ...... a _n } and N={b ₀ , b ₁ , b ₂ . . . b _n }.

标准模特变换不同位置，重复上述计算过程，可获得换算因子向量K＝{k₀,k₁,k₂…..k_n}。The conversion factor k _j in the above detection method formula (2) is obtained by the following method: looking for a person with a height of h as a calibration model, making him wear a nylon fabric and stepping on a plastic pad, and then apply an electrostatic voltage U ₀ to his body. And keep the normal standing posture and place it under the ceiling position F={f ₀ , f ₁ , f ₂ ...... f _n }, when it is in a position J, according to the formula U'=a _J ·A'+b _J Calculate the electrostatic voltage U ₀ ' of the calibration model collected by the quantitative non-contact detection device for the electrostatic field of the human body, and then calculate the conversion factor k _j between the standard model and the aluminized ball at this position,

The standard model is transformed into different positions, and the above calculation process is repeated to obtain a conversion factor vector K={k ₀ , k ₁ , k ₂ .....k _n }.

The quantitative non-contact detection device for human electrostatic field in this embodiment is a non-contact device that can quantitatively calculate electrostatic voltage. The person to be tested only needs to stand under the detection device, combined with a binocular vision camera, through the detection method of this embodiment. The electrostatic voltage level of the person can be automatically calculated, with a high degree of automation and accurate detection.

Claims (4)

1. The utility model provides a human electrostatic field ration non-contact detection device which characterized in that: the device comprises a grounding shielding cover, a shielding layer, a motor, a first coil, a second coil, an insulating disc, a metal fan, a capacitor, a synchronous control module and an amplification band-pass module, wherein the shielding layer divides the grounding shielding cover into an upper layer and a lower layer, the motor is arranged on the upper layer, the first coil, the second coil, the insulating disc and the metal fan are arranged on the lower layer, a shaft of the motor penetrates through the shielding layer to be connected with the metal fan, the shielding layer, the first coil and the metal fan are all subjected to grounding treatment, the insulating disc is fixedly arranged and is paved with a plurality of copper foils, the number, the shape and the area of the copper foils are the same as the number, the shape and the area of metal fan blades, the second coil is connected with the copper foils of the insulating disc, the capacitor is connected between the first coil and the second coil to be used as the input of the amplification band-pass module, the synchronous control module drives the motor and controls the rotating speed of the motor.

2. The method for detecting the electrostatic field of the human body by adopting the quantitative non-contact detection device of the electrostatic field of the human body as claimed in claim 1 is characterized by comprising the following steps:

s1, mounting the human body electrostatic field quantitative non-contact detection device on the ceiling to form a test area, and dividing the test area into different positions F ═ F₀,f₁,f₂…..f_n}，

S2, calibrating the quantitative non-contact human body electrostatic field detection device at different positions to obtain coefficient vectors M ═ a corresponding to the positions₀,a₁,a₂…..a_nAnd N ═ b₀,b₁,b₂…..b_n}，

S3, standing the human body to be tested at a certain position J in the test area, measuring the height h 'of the discharge tip of the human body to be tested by using a binocular camera, outputting a sine wave electrostatic field transmitting value with the amplitude A' through a human body electrostatic field quantitative non-contact detection device,

according to the formula U' ═ a_J·A′+b_J(1) Roughly calculating the electrostatic voltage of the human body to be measured, wherein a_JFor the coefficients in the coefficient vector M corresponding to position J, b_JFor the coefficients in the coefficient vector N corresponding to position J,

according to the formula

Accurately calculating the electrostatic voltage of the human body to be measured, wherein k_jFor the conversion factor, H is the height of the ceiling and H is the height of the calibration model.

3. The method for detecting the electrostatic field of the human body according to claim 2, wherein the method for calibrating the quantitative non-contact detection device for the electrostatic field of the human body comprises the following steps:

s1, adopting the diameter of R_bThe aluminum-plated ball is used as an equivalent charged model of a human body, and the metal ball is placed at a plane position f (x)₀,y₀) And by insulationThe support fixes the aluminized balls at a position L away from the ceiling,

s2, generating a voltage U by using a high-voltage generator₀Charging the aluminum-plated ball to generate an electrostatic field, wherein the value of the electrostatic field actually transmitted to the detection module is E₀，

S3 gradient adjustment U₀And recording the electrostatic field transmission value A, to U output by the amplifying band-pass module₀Linear fitting is established according to the relation between the formula and A to obtain a formula U₀＝a₀·A+b₀(4)，

S4, placing the aluminum-plated balls at different planar positions in the test area, and repeating steps S2 and S3 to obtain coefficients corresponding to the different planar positions, i.e., coefficient vector M ═ a₀,a₁,a₂…..a_nAnd N ═ b₀,b₁,b₂…..b_n}。

4. The method for detecting the electrostatic field of the human body according to claim 2, wherein the scaling factor k is_jIs obtained by the following method: searching a person with height h as a calibration model, putting the person on a nylon fabric and stepping on a plastic pad, and applying an electrostatic voltage U to the whole body₀And keeping the normal standing pose at the position F ═ F below the ceiling₀,f₁,f₂…..f_nWhen it is in a position J, a' according to the formula U ═ a_J·A′+b_JCalculating the electrostatic voltage U of the calibration model collected by the human body electrostatic field quantitative non-contact detection device₀' and then calculating the conversion factor k between the standard model and the aluminized ball at the position_j，

Converting different positions by the standard model, repeating the calculation process to obtain a vector K of the conversion factor (K) { K }₀,k₁,k₂…..k_n}。

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