RU2795996C1 - Device for detection of toxic chemical substances - Google Patents

Abstract

FIELD: indication of toxic chemicals in the atmosphere.

SUBSTANCE: invention can be used for chemical reconnaissance using an unmanned aerial vehicle (UAV). The device for determining toxic chemicals contains three indicator elements for hazardous chemicals and chemical weapons, a colour recognition module using detectors based on analysis of the reflected electromagnetic radiation of the optical range, LEDs necessary to ensure the correct illumination of the detector microchip, the detector microchip calculates the chromaticity and saturation of the reflected beam and compares the obtained results with the previously set values of colour coordinates, while information about the recognized colour in form of encoded sequence is transmitted to the controller of the ground display device via radio channel using two telemetry radio modules through protocol for information interaction with unmanned aerial vehicles (UAVs), this information about presence and concentration of toxic chemicals is transmitted in real time to the operator, located at a distance from the contaminated area or object.

EFFECT: providing prompt determination of presence and concentration of hazardous chemicals and chemical weapons in an infected area or object in real time and without contact of the researcher with infected objects.

1 cl, 6 dwg

Description

The invention relates to the field of indication of toxic chemicals in the atmosphere and can be used for chemical reconnaissance using an unmanned aerial vehicle (UAV).

The proposed device is aimed at achieving a technical result, which consists in the analysis of the air under study in the area of possible contamination with toxic chemicals, the control of the color change of the indicator elements by a color recognition module - a detector based on the analysis of the reflected electromagnetic radiation of the optical range and transmission to the microchip to calculate the chromaticity and saturation reflected beam, comparing the obtained results with previously specified values of color coordinates. Transmission of information about the recognized color in the form of a coded sequence to the controller of the ground display device via a radio channel using two telemetry radio modules via the protocol for information exchange with unmanned aerial vehicles (UAVs).

Known designs of devices for indicating toxic chemicals, such as a military chemical reconnaissance device (VPKhR), military automatic gas detectors of various modifications (GSA), a radiation and chemical reconnaissance device (PRKhR) and a military individual chemical control kit (VIKKhK).

Disadvantages of existing devices for indicating toxic chemicals:

- the researcher of the area of infection must be located together with the device for indicating toxic chemicals in the zone of possible contamination, which in due time can lead to the defeat of the researcher;

- it takes quite a long time to move to the area and return from the area of possible infection

- after performing chemical reconnaissance measures, it is necessary to carry out degassing measures not only for transport, but also for the display device, as well as for sanitizing the researcher himself.

Based on the above shortcomings, the actual issue of indicating toxic chemicals is the creation of a mobile display device with remote transmission of chemical intelligence data to a safe distance.

The essence of the invention lies in the fact that during the flight of the UAV through a cloud of toxic substances, a fine aerosol of an emergency chemically hazardous substance (AHOV) or a toxic military chemical substance (BTCS) enters the device (payload) through a tapering nozzle and, under the influence of air pressure, is distributed in three directions (guides), in each of which an indicator flat element (IPE) is installed, perpendicular to the direction of the air flow, on the investigated AHOV (BTXV), where the indication takes place and the presence of them in the atmosphere is determined by color change. The device can simultaneously use three IPEs for various types of AHOV or BTXV.

To determine the optical parameters of a chemical reaction, the device uses color recognition modules - detectors based on the analysis of reflected electromagnetic radiation in the optical range. The modules are designed on the basis of a sensitive element - a TCS230/TCS3200 microchip with an optimal distance for color recognition of 10 mm. The principle of operation of the detector is based on the method of determining three colors. The white LEDs of the color recognition module emit white light, which includes three color components (red, blue, green). The LEDs are necessary to ensure proper illumination of the detector's microchip. The detector's microchip calculates the chromaticity and saturation of the reflected beam and compares the obtained results with previously set values of color coordinates. If the results of the comparative analysis are within tolerance, an output electrical signal of a certain frequency is generated, shown in figure 1.

The microchip should consist of an array of 8×8 photodiodes, 64 in total, of which 16 photodiodes have a red filter, 16 have a green filter, 16 have a blue filter, and the remaining 16 are transparent without filters. The filters of each color are distributed evenly throughout the array. Each filter type can be activated using digital inputs S2 and S3. Figure 2 shows the relationship between S2, S3 and filter type.

At the output, the color recognition module produces a rectangular signal with a duty cycle of 50% with a frequency proportional to the color intensity. The detector output frequencies range from 2 Hz to 500 kHz. To scale the output frequency with values of 100%,

20% and 2% in order to optimize the output signal of the detector for various frequency counters and microcontrollers use two programmable outputs - SO and S1, as shown in figure 3.

For finer tuning of the output signal to the corresponding color, the 100% type is used, for which a high signal level is applied to the digital inputs SO, S1.

The detector has different sensitivity to red, green and blue colors. As a result, the RGB output of pure white is not always 255. Therefore, after turning on the power, white balance calibration is required within 2 seconds. The calibration algorithm is represented by the following sequence of actions:

- Place white paper at a distance of 10mm from the sensor and apply high voltage (3.3V) to the LED port to turn on the backlight (4 bright LEDs on the detector body).

- The program selects the R (red), G (green) and B (blue) filters respectively and measures the corresponding RGB values of red, green and blue.

- Calculate 3 adjustment parameters corresponding to red, green and blue and perform auto white balance adjustment.

The detector is connected to the onboard controller based on Arduino Mega as shown in figure 4.

An additional two detectors are connected to common contacts D3, D4, D5, D6 of the onboard controller.

To determine a predefined color, you must:

- Place a colored object (test indicator flat element) at a distance of 10 mm and apply high voltage (3.3 V) to the LED port to light up the backlight (4 bright LEDs on the detector body);

- Compose a program for the on-board controller, which sequentially, applying all three light filters in turn, outputs three parameters R, G, B. The values of these parameters will be in the range from 0 to 255;

- Repeat step 2 at least 100 times, calculate the mathematical expectation and standard deviation for each three color parameters using the formulas:

where: x _ξ - the value of the color parameter from the range [0;255]; ξ - color parameter R, G or B; n is the number of tests performed.

- Determine in the program the value of each parameter for a given color, taking into account the standard deviation;

- Place any of the previous objects at a distance of 10 mm from the detector with the LEDs on to recognize the color of the object.

The full-color detector is powered by a DC voltage of 3.3 V and 5 V by means of a rechargeable battery installed as a UAV power module through a DC-DC step-down voltage converter with the following characteristics:

input voltage 4-38 V; output voltage 1.25-36 V (adjustable); output current 0-5A (recommended current 4.5A); operating frequency 180 kHz; power 75 W; working temperature from minus 40-85°С.

Information about the recognized color in the form of a coded sequence of bytes is transmitted to the controller of the ground display device via a radio channel using two telemetry radio modules via the MAVLink (MicroAirVehicleLink) protocol for information interaction with unmanned aerial vehicles (UAVs). MAVLink is distributed under the LGPL license as a module for Python and libraries for various languages, including header-only C/C++ libraries, which makes it easy and accessible to use for low-loss data transfer tasks. The basic entity of MAVLink is a package having the format shown in figure 5.

The first byte of the packet (STX) is the start character of the message: 0xFD for v2.0, 0xFE for v1.0, 0x55 for v0.9. LEN - payload (message) length. SEQ - Contains a packet counter (0-255) that detects message loss. SYS (System ID) is the identifier of the sending system, and COMP (Component ID) is the identifier of the sending component. MSG (Message ID) - message type, it determines what data will be in the payload of the packet. PAYLOAD - packet payload, message, size from 0 to 255 bytes. The last two bytes of the packet - SKA and SKB, the lower and upper byte, respectively, contain the checksum of the packet. The MAVLink library allows you to encode and decode packets according to the protocol, processing the input data byte by byte, adding them to the buffer and collecting the packet shown in figure 5 from them.

These radio modules must support full-duplexcommunicationthroughadaptive TDM and have a physical implementation of the UART (Universalasynchronousreceiver/transmitter) interface for data exchange with the onboard controller. Transceiver power. must satisfy the required range of the UAV, taking into account meteorological conditions, radiation conditions and terrain.

Antennas for radio modules are set based on the following parameters: resonant frequency, input impedance, radiation pattern, gain, polarization. The resonant frequency for this device must be 915 MHz or 433 MHz. The characteristic impedance of the antenna must be equal to the characteristic impedance of the supply cable, as well as the output impedance of the transmitter. The value of the wave resistance in all sections should be equal to 50 ohms. The antenna of the transmitting and receiving radio must have a non-uniform radiation pattern for a more pronounced directional action.

The radio module is powered by a DC voltage of 5 V by means of a rechargeable battery installed as a power supply module for the UAV and connected through a DC-DC step-down voltage converter.

For correct data transfer, the following parameters of the serial port of the on-board controller and the controller of the display device are set: baudrate 57600; databits 8; stop bit 1; paritybit NONE. The baudrate parameter varies depending on the model of the radio module used. The operation diagram of the BTXV and AHOV display device is shown in figure 6.

Claims (1)

The device for determining toxic chemicals contains three indicator elements for a combat toxic chemical substance (BTCS) or an emergency chemically hazardous substance (AHOV), a color recognition module - detectors based on the analysis of reflected electromagnetic radiation in the optical range, LEDs necessary to ensure proper lighting detector microchip, the detector microchip calculates the chromaticity and saturation of the reflected beam and compares the obtained results with the previously specified values of color coordinates, while information about the recognized color in the form of an encoded sequence is transmitted to the controller of the ground display device via a radio channel using two telemetry radio modules through an information interaction protocol with unmanned aerial vehicles (UAVs), while this information about the presence and concentration of toxic chemicals is transmitted in real time to an operator located at a distance from the contaminated area or object.

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