CN112255282A

CN112255282A - Binary mixed gas concentration detector based on information fusion technology

Info

Publication number: CN112255282A
Application number: CN202011084642.6A
Authority: CN
Inventors: 景元杰; 丁喜波
Original assignee: Harbin University of Science and Technology
Current assignee: Harbin University of Science and Technology
Priority date: 2020-10-12
Filing date: 2020-10-12
Publication date: 2021-01-22

Abstract

The invention provides a binary mixed gas concentration detector based on information fusion technology, which mainly comprises a thermal conductivity sensor, a catalytic combustion sensor, an ultrasonic sensor, a temperature sensor, a humidity sensor, a singlechip, a GPRS module and a Labview upper computer, wherein the gas information is processed and transmitted to the singlechip processor from a signal acquisition end through filtering, amplification, A/D conversion and the like by utilizing different sensitivity degrees of the thermal conductivity sensor, the thermal catalysis sensor and the ultrasonic sensor to methane and hydrogen, the gas is identified through a logic algorithm, the regression algorithm is adopted to carry out fusion processing on the data, the concentration of the two gases is finally obtained, the obtained gas concentration is transmitted to the GPRS wireless communication module through RS232 serial port communication, then the display reminding is carried out through a Labview upper computer, a warning value is set, and when the concentration exceeds the warning value, the singlechip controls the sound-light alarm circuit to alarm. The design integrates the information of a plurality of sensors, and the concentration values of the hydrogen and the methane can be detected in real time more accurately.

Description

Binary mixed gas concentration detector based on information fusion technology

Technical Field

The invention relates to a multi-sensor information fusion technology, in particular to a binary mixed gas concentration detector based on the information fusion technology.

Background

With the rapid development of modern industry, the measurement of the concentration of the mixed gas of methane and hydrogen generates urgent needs in various fields, for example, the analysis of methane and hydrogen in biogas is one of the most direct indexes for judging the working state of an anaerobic fermentation system, and the analysis of the contents of the two gases of methane and hydrogen has important significance for the regulation and control of biogas production. And the mixed gas of methane and hydrogen is used as fuel, and the detection of the concentration is also significant for the use of the fuel proportion. The invention designs the concentration detector of the hydrogen and methane mixed gas, improves the accuracy and reliability of gas concentration detection and widens the concentration range of gas detection on the basis of reducing the cost as much as possible.

Disclosure of Invention

The invention provides a binary gas concentration detection method based on an information fusion technology, which integrates a plurality of sensors, overcomes the problems of cross response, inaccurate detection result and the like existing when a single sensor detects the concentration of multi-component gas, comprehensively describes the gas concentration from the chemical property and the physical property of the gas, accurately detects the respective concentrations of hydrogen and methane in hydrogen and methane mixed gas, and displays the concentrations on a Labview host computer through GPRS wireless communication.

The purpose of the invention is realized as follows:

the utility model provides a binary mixed gas concentration's detection method based on information fusion technique, includes two parts of host computer and next machine, its characterized in that: the lower computer part comprises a plurality of sensors such as a catalytic combustion type sensor, a thermal conductivity sensor, an ultrasonic sensor, a temperature and humidity sensor and a singlechip, signals of the sensors are processed and then sent into the singlechip to be subjected to information fusion processing, the singlechip processor is also connected with an acousto-optic alarm circuit, a storage circuit and a GPRS module, communication is realized with a Labview upper computer through a GPRS wireless module, and 3 steps are mainly completed: collecting signals, processing data and displaying alarm;

the signal acquisition end comprises a thermal conductivity type sensor, a catalytic combustion type sensor and an ultrasonic sensor, and the gas signals are transmitted to the single chip microcomputer through a filtering amplification circuit, a sampling holding circuit and an A/D conversion circuit after being acquired; the data processing part accesses data through the singlechip and the storage circuit, analyzes and identifies methane or hydrogen through an algorithm and obtains the concentration; the display alarm part comprises a GPRS module and a Labview upper computer, the single chip microcomputer is connected to the GPRS module through an RS232 serial port, then information is sent to the upper computer to be displayed, an alarm value is set, and an interface pops up to alarm when the gas concentration exceeds the alarm value.

Compared with the prior art, the invention has the following beneficial effects:

1. the detection method for the concentration of the binary mixed gas adopts a multi-sensor system with multi-parameter acquisition and a data fusion method to detect the concentration of methane and hydrogen, and in view of the defects of the traditional gas detection mode, the detector starts from different response characteristics of a plurality of different sensors to gas, analyzes different responses of the mixed gas to the output of the sensors from multiple characteristics, well makes up the limitation of a single sensor, improves the measurement precision and realizes the real-time detection of the mixed gas of methane and hydrogen.

2. The invention is connected to the upper computer through GPRS wireless communication, separates the detection module from the display module, and can control and display the lower computer through the upper computer, so that the design is more flexible and the use is more convenient.

Drawings

FIG. 1 shows the overall structure of the detector

FIG. 2 is a flow chart of information fusion

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

A binary mixed gas concentration detector based on an information fusion technology comprises an upper computer and a lower computer, which are shown in figures 1 and 2. The method is characterized in that: the lower computer part comprises a plurality of sensors such as a catalytic combustion type sensor, a thermal conductivity sensor, an ultrasonic sensor, a temperature and humidity sensor and a singlechip, signals of the sensors are processed and then sent into the singlechip to be subjected to information fusion processing, the singlechip processor is also connected with an acousto-optic alarm circuit, a storage circuit and a GPRS module, communication is realized with a Labview upper computer through a GPRS wireless module, and 3 steps are mainly completed: collecting signals, processing data and displaying alarm;

The core of the research of the information fusion technology is the corresponding relation between the input quantity and the output quantity of the sensor, the heat conduction type sensor and the thermal catalysis type sensor generate different influences on a Wheatstone bridge in the sensor when gas with different concentrations flows through a catalytic element, so that the bridge balance is broken to output a voltage signal, and the ultrasonic sensor obtains an output signal through the positive and negative piezoelectric effect of the sensor. The detector processes the output signal of the sensor by adopting a regression equation and a least square method. Firstly, signal preprocessing is carried out on six sensors, and a preprocessing algorithm adopted by a plurality of sensors is an array normalization algorithm. In this context, six sensors are used in parallel, but in actual operation, the thermocatalytic sensors respectively detect the concentrations of hydrogen and methane, so that the response output of the sensors to the mixed gas at a certain moment is a vector of five-dimensional states [ Xgas1, Xgas2, Xgas3, Xgas4, Xgas5 ]:

where n is the total number of sensors in the array. For the detection of methane concentration, the processor analyzes the data transmitted by the high temperature thermocatalytic sensor, the thermal conductivity sensor and the ultrasonic sensor, and assuming that the sampling period of the sensors is 1s, the output of five sensors in Ns is a matrix Xij of rows N and columns 5. And (3) establishing a relation model between an actual value and a predicted value by taking the predicted value in N seconds as data:

Yⁱ＝θ^Tx⁽ⁱ⁾+εⁱ (2)

where θ is the coefficient between the sensor output and the predicted value, ε is the error between the predicted value and the true value, is usually independent and has the same distribution, we consider it to be obeying a mean of 0 and a variance of θ²Is a Gaussian distribution of

Substituting formula (2) into formula (3) can result in:

thereby, a likelihood function is obtained:

when the target function is minimum, the more the predicted value is close to the true value, the coefficient between the sensor output value and the predicted value can be obtained:

θ＝(X^TX)^-1X^TY (6)

the hydrogen concentration can be obtained by processing the data of the low-temperature thermocatalytic sensor and the thermal conductivity and ultrasonic sensor by the same method.

Claims

1. The utility model provides a binary mixed gas concentration detector based on information fusion technique, includes two parts of host computer and next computer, its characterized in that: the lower computer part is composed of a plurality of sensors such as a catalytic combustion type sensor, a thermal conductivity sensor, an ultrasonic sensor and the like and a PIC single chip microcomputer, and the upper computer is developed on a PC machine by LABVIEW.

2. The binary mixed gas concentration detector based on the information fusion technology as claimed in claim 1, wherein the concentration value of the binary mixed gas is output simultaneously from the upper computer by means of an information fusion algorithm.

3. The binary mixed gas concentration detector according to claim 1, wherein: the sensors are respectively two thermal conductivity sensors, two catalytic combustion sensors and two ultrasonic sensors; the ultrasonic sensor is a piezoelectric ultrasonic sensor and comprises a transmitting probe and a receiving probe.

4. The binary mixed gas concentration detector according to claim 1, wherein: the thermocatalytic sensors perform catalytic combustion on hydrogen and methane at high temperature and low temperature respectively, and data of the two thermocatalytic sensors are fused with other sensors respectively during data fusion.