Vehicle-mounted sensor calibration and evaluation system and method

Abstract

The invention provides a vehicle-mounted sensor calibration and evaluation system and method. Belongs to the field of sensor measurement calibration. The system comprises a gas distribution system, a reaction box, a standard instrument and an industrial personal computer, and is used for simulating different atmospheric environments and calibrating the sensor. The gas distribution system is responsible for loading standard gas, sample gas or water vapor, the reaction box adjusts environmental parameters through an ultraviolet lamp and a temperature and humidity controller which are arranged in the reaction box, and a preset atmospheric environment is simulated. The reaction box is connected with a standard instrument so as to compare standard data with sensor data, and calibration of the sensor is achieved. All the devices are connected with the industrial personal computer, so that data control, acquisition and display are realized. According to the method, the calibration process is completed through the steps of simulating the atmospheric environment, recording original data, obtaining standard data, calculating deviation, adjusting data, evaluating the calibration effect and the like, the method has the advantages of being easy to operate, accurate in effect, wide in applicability, capable of being used on a vehicle and the like, and the accuracy and stability of the sensor can be effectively improved.

Description

Technical Field

[0001] The invention belongs to the field of sensor measurement and calibration, and more specifically relates to a vehicle-mounted sensor calibration and evaluation system and method. Background Art

[0002] At present, sensor monitoring technology is very mature, and the use of sensors to monitor six parameters of air quality has been widely used. In recent years, all cities have carried out grid-based air quality monitoring based on sensors. Sensors need to be calibrated and evaluated before leaving the factory and after a period of use (usually 1 year). Sensor grid monitoring is mostly used in large-scale urban deployment. Sensors are distributed in a wide area and in large numbers. To meet this demand, a vehicle-mounted sensor calibration and evaluation system has been invented.

[0003] Sensor manufacturers calibrate and evaluate sensors before they leave the factory and after they have been used for a period of time mainly based on testing with standard gases of known concentration or synchronous comparison based on standard instruments. There is a lack of calibration and evaluation systems for simulating different states of the atmospheric environment and different environmental samples (such as pollution source samples). In addition, calibration and evaluation are usually performed at fixed points, which is not flexible enough and cannot meet the current grid-based sensor calibration and evaluation needs in cities.

[0004] 1. The existing system cannot simulate the real atmospheric environment under different conditions to calibrate and evaluate the sensor in various situations;

[0005] 2. The existing system cannot carry out sensor calibration and evaluation of different environmental sample gases;

[0006] 3. The existing system lacks an integrated method for vehicle-mounted use, is not flexible enough in operation, and cannot meet the needs of large-scale sensor calibration and evaluation in urban areas. Summary of the invention

[0007] The present invention aims to solve the following technical problems: the existing sensor calibration and evaluation system cannot simulate various conditions in the real atmospheric environment, cannot carry out sensor calibration and evaluation work for different environmental sample gases, and is not flexible enough in operation and lacks an integrated system that is easy to use on a vehicle, and cannot meet the calibration and evaluation needs of a large number of sensors distributed in large cities.

[0008] In order to achieve the above object, the present invention is implemented by adopting the following technical scheme: the system comprises a gas distribution system, a reaction box, a standard instrument and an industrial computer;

[0009] The gas distribution system is loaded with standard gas, sample gas or water vapor to obtain sample gas with preset concentration and humidity, and then sent to the dynamic calibrator;

[0010] The reaction box is equipped with an ultraviolet and temperature and humidity controller, including an ultraviolet lamp and a semiconductor cooling chip, to adjust the ultraviolet light intensity and temperature and humidity in the reaction box to simulate the atmospheric environment under different conditions;

[0011] One end of the reaction box is connected to a standard instrument, and the other end is connected to a dynamic calibrator, sample gas is introduced and compared with the sensor data to achieve sensor calibration;

[0012] The gas distribution system, reaction box and standard instruments are all connected to the industrial computer to realize the control, collection and display of the intake type, intake concentration, reaction box ultraviolet light intensity, temperature and humidity, sensor data and standard instrument data.

[0013] In one aspect, a vehicle-mounted sensor calibration and evaluation method, the method being applicable to the system, the method comprising:

[0014] (1) Setting environmental parameters and simulating the environment: Select the environmental parameters to be simulated; add a preset concentration and type of gas into the reaction box through the gas distribution system, adjust the light intensity and temperature and humidity through the ultraviolet and temperature and humidity controllers in the reaction box, and simulate the preset atmospheric environment;

[0015] (2) Start the sensor to be calibrated in a simulated atmospheric environment and record the raw response data of the sensor under various environmental conditions;

[0016] (3) introducing the same gas in the reaction box into a standard instrument for detection to obtain standard measurement data;

[0017] (4) Compare the sensor response data with the measurement data of the standard instrument, calculate the deviation, and correct the sensor reading so that it is consistent with the data of the standard instrument under the same environmental conditions;

[0018] (5) Evaluation of calibration effect: Use the corrected sensor to test in the same or different simulated environments, record the new response data, compare it with the data difference of the standard instrument, and evaluate the accuracy, stability and performance of the sensor under various environmental conditions.

[0019] In one solution, the environmental parameters are set by setting the preset gas type, concentration and humidity value through an industrial computer, and by adjusting valves and flow meters, the ratio of various gases entering the reaction box is accurately adjusted to achieve the preset gas concentration;

[0020] Humidity regulation is achieved through the amount of water vapor added to the gas distribution system;

[0021] The temperature is regulated by the temperature control system of the reaction box;

[0022] The intensity of the ultraviolet light is achieved by adjusting the light intensity of the ultraviolet lamp in the reaction box.

[0023] In one solution, the original response data of the sensor is obtained by connecting the sensor to an industrial computer via a data line, and the sensor under test automatically detects the atmospheric environment in the reaction box; the sensor response data under various environmental conditions is recorded by the industrial computer.

[0024] In one solution, the standard measurement data is connected to the standard instrument with the reaction box and the industrial computer, the measurement data of the standard instrument is transmitted to the industrial computer, the valve connecting the reaction box and the standard instrument is opened, and the standard instrument starts to automatically measure the inflowing gas, detects various components, concentrations, and humidity parameters in the gas, and generates corresponding standard data.

[0025] In one embodiment, the comparison of the measured data includes calculating the deviation of the two data sets and calculating the average difference between the two data sets, which is achieved by the following formula: Where i represents each measurement point, and n represents the number of measurement points;

[0026] Data calibration, using linear calibration to adjust sensor data, that is, adding or subtracting the calculated deviation from each value to make the sensor data close to the standard data;

[0027] Linear calibration is expressed in the following form:

[0028] Calibrated data = a*original data + b;

[0029] Among them, a is the standard slope and b is the standard intercept.

[0030] In one embodiment, the calibration effect is evaluated by comparing and calculating the new response data with the data of the standard instrument using the mean square error (MS), which is expressed by the following formula:

[0031]

[0032] Among them, i represents each measurement point, and n represents the number of measurement points;

[0033] The accuracy and stability of the sensor can be evaluated based on the MSE mentioned above. The higher the accuracy, the smaller the MSE. The stability can be evaluated by calculating the standard deviation of the sensor's measurement results at different time points and under the same environmental conditions. The smaller the standard deviation, the better the stability.

[0034] Through the above data, the response data of the sensor under different gas concentrations, humidity, temperature and ultraviolet light intensity are compared to see whether the response of the sensor is consistent under different environmental conditions and whether the change of the response is consistent with the change of environmental conditions, so as to evaluate the performance of the sensor.

[0035] In one embodiment, the values ​​of a and b are obtained by linear regression analysis based on sensor data (X) and standard data (Y). In the linear regression, a line with the smallest deviation is taken as the result, that is, Y=aX+b is obtained by solving;

[0036] The resulting slope and intercept (a and b) are applied to the sensor readings to obtain the calibrated sensor data.

[0037] Beneficial effects of the present invention:

[0038] 1. The present invention can simulate the real atmospheric environment under different conditions by adjusting the intake air type, intake air concentration, ultraviolet light intensity, temperature and humidity in the reaction box, and can calibrate and evaluate the sensor under various conditions;

[0039] 2. Different from the traditional calibration method, the present invention can carry out sensor calibration and evaluation work for different environmental sample gases;

[0040] 3. The present invention integrates various parts into a vehicle-mounted system, which can directly carry out sensor calibration and evaluation of simulated real atmospheric environment and standard gas in the field and on site. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a system block diagram of the present invention;

[0042] Figure 2 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0043] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Typical embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in the present invention. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0044] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0045] Embodiment 1:

[0046] like Figure 1As shown, the vehicle-mounted sensor calibration and evaluation system is composed of a gas distribution system, a reaction box, a standard instrument and an industrial computer. The gas distribution system can load sample gas (such as pollution source gas) into the reaction box, or load standard gas and water vapor of known concentration. The gas passes through a dynamic calibrator and is configured into a sample gas of known concentration and humidity to enter the reaction box. The reaction box is equipped with an ultraviolet and temperature and humidity controller (ultraviolet lamp and semiconductor refrigeration sheet) to adjust the ultraviolet light intensity and temperature and humidity in the reaction box. By controlling the different loaded gases and the ultraviolet light intensity and temperature and humidity in the reaction box, the real atmospheric environment under different conditions is simulated. The sensor is carried in the reaction box for calibration and evaluation, which is used to test the response of the sensor under different pollutant types, different pollutant concentrations and different atmospheric environments. One end of the reaction box is connected to a standard instrument, and the sample gas is introduced into the standard instrument for monitoring through a switch valve, which is used to carry out synchronous comparison between the sensor and the standard instrument. The gas distribution system, reaction box and standard instruments are all connected to the industrial computer to realize the control and collection and display of the intake type, intake concentration, reaction box UV intensity, temperature and humidity, sensor data and standard instrument data. Each part is integrated into a vehicle-mounted system, which can be used for field and on-site sensor calibration and evaluation.

[0047] Embodiment 2:

[0048] like Figure 2 As shown, a vehicle-mounted sensor calibration and evaluation method, the method is applicable to the system, the method comprises:

[0049] S1. Set environmental parameters and simulate the environment: select the environmental parameters to be simulated; add the preset concentration and type of gas into the reaction box through the gas distribution system, adjust the light intensity and temperature and humidity through the UV and temperature and humidity controller in the reaction box to simulate the preset atmospheric environment.

[0050] The specific implementation of setting environmental parameters is mainly completed by the control system of the gas distribution system and the reaction box. First, the preset gas type, concentration and humidity value are set through the industrial computer. For example, if you want to simulate a highly polluted environment, you can set the corresponding concentration values ​​of various pollutants such as SO2, NO2, PM2.5, etc. Then, in the gas distribution system, by adjusting the valves and flow meters, the proportion of various gases entering the reaction box is accurately adjusted to achieve the preset gas concentration.

[0051] Humidity regulation mainly depends on the amount of water vapor added through the gas distribution system. Similarly, by setting the expected humidity value, the amount of water vapor added to the reaction box is controlled through the valves and flow meters of the gas distribution system to achieve the preset humidity. Temperature regulation is completed by the temperature control system of the reaction box. According to the preset value, the temperature control system of the reaction box adjusts the power output to achieve the predetermined temperature. The intensity of ultraviolet light is achieved by adjusting the light intensity of the ultraviolet lamp in the reaction box. By setting the ultraviolet light intensity value, the power supply voltage of the ultraviolet lamp is adjusted to change its light intensity.

[0052] These environmental parameters are set through the user interface of the industrial computer. Users can easily set these parameters according to actual needs or experimental purposes to simulate various environmental conditions. They can meet the needs of testing the response of sensors in different environments (such as various pollution levels, temperatures, humidity, and ultraviolet light intensity).

[0053] S2. In a simulated atmospheric environment, start the sensor to be calibrated and record the original response data of the sensor under various environmental conditions.

[0054] First, connect the sensor to the industrial computer through a data cable to ensure that the sensor to be tested can normally receive signals from the industrial computer and send the measured data to the industrial computer for recording and analysis. Start the sensor switch on the industrial computer to start the sensor to work. The sensor to be tested automatically senses the atmospheric environment in the reaction box and generates corresponding data. The sensor response data under various environmental conditions is recorded through the industrial computer. The specific response data includes the measured values ​​of various parameters of the sensor when the environmental conditions such as different concentrations and types of gases, different humidity, different temperatures and different ultraviolet light intensities change. Through the user interface of the industrial computer, various data and monitoring results are displayed in real time, which is convenient for users to understand the experimental progress and status, find problems in time and make adjustments.

[0055] S3. Introduce the same gas in the reaction box into a standard instrument for detection to obtain standard measurement data.

[0056] Connect the standard instrument to the reaction box and the industrial computer. The purpose of this is to allow the gas in the reaction box to flow into the standard instrument and the measurement data of the standard instrument to be transmitted to the industrial computer. Open the valve connecting the reaction box and the standard instrument manually or automatically to allow the gas in the simulated atmospheric environment in the reaction box to flow into the standard instrument. Make sure that the gas detected is the same gas as the gas detected by the sensor. The standard instrument starts to automatically measure the inflowing gas, detects various parameters such as the composition, concentration, humidity, etc. in the gas, and generates corresponding measurement data. Finally, the data measured by the standard instrument is transmitted to the industrial computer, and the staff receives and views the data through the industrial computer.

[0057] S4. Compare the response data of the sensor with the measurement data of the standard instrument, calculate the deviation, and correct the reading of the sensor so that it can be consistent with the data of the standard instrument under the same environmental conditions.

[0058] The comparison of the measured data includes calculating the deviation of the two data sets and calculating the average difference between the two data sets, which is achieved by the following formula:

[0059] Where i represents each measurement point, and n represents the number of measurement points;

[0060] Data calibration, using linear calibration to adjust sensor data, that is, adding or subtracting the calculated deviation from each value to make the sensor data close to the standard data;

[0061] Linear calibration is expressed in the following form:

[0062] Calibrated data = a*original data + b;

[0063] Among them, a is the standard slope and b is the standard intercept.

[0064] The values ​​of a and b are obtained by linear regression analysis based on the sensor data (X) and the standard data (Y). In the linear regression, the line with the smallest deviation is taken as the result, that is, the solution is Y=aX+b;

[0065] The resulting slope and intercept (a and b) are applied to the sensor readings to obtain the calibrated sensor data.

[0066] S5. Evaluate the calibration effect: Use the corrected sensor to test in the same or different simulated environments, record the new response data, compare it with the data difference of the standard instrument, and evaluate the sensor's accuracy, stability and performance under various environmental conditions.

[0067] The calibration effect is evaluated by comparing and calculating the new response data with the data of the standard instrument using the mean square error (MS), which is expressed by the following formula:

[0068]

[0069] Among them, i represents each measurement point, and n represents the number of measurement points;

[0070] The accuracy and stability of the sensor can be evaluated based on the MSE mentioned above. The higher the accuracy, the smaller the MSE. The stability can be evaluated by calculating the standard deviation of the sensor's measurement results at different time points and under the same environmental conditions. The smaller the standard deviation, the better the stability.

[0071] Through the above data, the response data of the sensor under different gas concentrations, humidity, temperature and ultraviolet light intensity are compared to see whether the response of the sensor is consistent under different environmental conditions and whether the change of the response is consistent with the change of environmental conditions, so as to evaluate the performance of the sensor.

[0072] Embodiment three:

[0073] First, preset environmental parameters to simulate a standard atmospheric environment. For example, we can set the gas concentration to 500ppm, the humidity to 50%, the UV intensity to 1500w / m^2, and the temperature to 25℃. These conditions can be precisely set by the gas distribution system and the UV and temperature and humidity controllers in the reaction box.

[0074] Then, we start the sensor to be calibrated, such as a CO2 sensor, and record the raw response data of the sensor under this environmental condition, such as a reading of 505ppm. After that, we introduce the same gas into a standard instrument, such as a standard CO2 analysis instrument, to obtain standard measurement data, such as a measurement result of 500ppm.

[0075] Next, we compare the sensor's response data with the standard instrument's measurement data and calculate the deviation, for example, 5ppm. After that, we adjust the sensor's reading so that it can be consistent with the standard instrument's data under the same environmental conditions, for example, adjusting the sensor reading from 505ppm to 500ppm.

[0076] After that, we can evaluate the calibration effect. We can test the calibrated sensor in the same or different simulation environment, record the new response data, and compare it with the data of the standard instrument to evaluate the accuracy and stability of the sensor. For example, under the conditions of gas concentration of 500ppm, humidity of 50%, UV intensity of 1500w / m^2, and temperature of 25℃, the new response data is 500ppm, which is consistent with the data of the standard instrument, and it is considered that the accuracy and stability of the sensor are good.

[0077] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM).

[0078] It should be understood that the detailed description of the technical solutions of the present invention by means of the preferred embodiments is illustrative rather than restrictive. A person skilled in the art may modify the technical solutions described in the embodiments, or replace some of the technical features by equivalents, based on reading the specification of the present invention; and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vehicle-mounted sensor calibration and evaluation system, characterized in that: Including gas distribution system, reaction box, standard instruments and industrial computers; The gas distribution system is loaded with standard gas, sample gas or water vapor to obtain sample gas with preset concentration and humidity, and then sent to the dynamic calibrator; The reaction box is equipped with an ultraviolet and temperature and humidity controller, including an ultraviolet lamp and a semiconductor cooling chip, to adjust the ultraviolet light intensity and temperature and humidity in the reaction box to simulate the atmospheric environment under different conditions; One end of the reaction box is connected to a standard instrument, and the other end is connected to a dynamic calibrator, sample gas is introduced and compared with the sensor data to achieve sensor calibration; The gas distribution system, reaction box and standard instruments are all connected to the industrial computer to realize the control, collection and display of the intake type, intake concentration, reaction box ultraviolet light intensity, temperature and humidity, sensor data and standard instrument data.

2. A vehicle-mounted sensor calibration and evaluation method, the method being applicable to the system as claimed in claim 1, characterized in that: The method includes: (1) Setting environmental parameters and simulating the environment: Select the environmental parameters to be simulated; add a preset concentration and type of gas into the reaction box through the gas distribution system, adjust the light intensity and temperature and humidity through the ultraviolet and temperature and humidity controllers in the reaction box, and simulate the preset atmospheric environment; (2) Start the sensor to be calibrated in a simulated atmospheric environment and record the raw response data of the sensor under various environmental conditions; (3) introducing the same gas in the reaction box into a standard instrument for detection to obtain standard measurement data; (4) Compare the sensor response data with the measurement data of the standard instrument, calculate the deviation, and correct the sensor reading so that it is consistent with the data of the standard instrument under the same environmental conditions; (5) Evaluation of calibration effect: Use the corrected sensor to test in the same or different simulated environments, record the new response data, compare it with the data difference of the standard instrument, and evaluate the accuracy, stability and performance of the sensor under various environmental conditions.

3. The vehicle-mounted sensor calibration and evaluation method according to claim 2, characterized in that: The environmental parameters are set by setting the preset gas type, concentration and humidity value through the industrial computer, and by adjusting the valves and flow meters, the ratio of various gases entering the reaction box is accurately adjusted to achieve the preset gas concentration; Humidity regulation is achieved through the amount of water vapor added to the gas distribution system; The temperature is regulated by the temperature control system of the reaction box; The intensity of the ultraviolet light is achieved by adjusting the light intensity of the ultraviolet lamp in the reaction box.

4. The vehicle-mounted sensor calibration and evaluation method according to claim 2, characterized in that: The original response data of the sensor is obtained by connecting the sensor to an industrial computer via a data line to detect the atmospheric environment in the reaction box; the sensor response data under various environmental conditions is recorded by the industrial computer.

5. The vehicle-mounted sensor calibration and evaluation method according to claim 2, characterized in that: The standard measurement data described above connects the standard instrument to the reaction box and the industrial computer, transmits the measurement data of the standard instrument to the industrial computer, opens the valve connecting the reaction box and the standard instrument, and the standard instrument starts to automatically measure the inflowing gas, detects various components, concentrations, and humidity parameters in the gas, and generates corresponding standard data.

6. A vehicle-mounted sensor calibration and evaluation method according to claim 2, characterized in that: The comparison of the measured data includes calculating the deviation of the two data sets and calculating the average difference between the two data sets, which is achieved by the following formula: Where i represents each measurement point, and n represents the number of measurement points; Data calibration, using linear calibration to adjust sensor data, that is, adding or subtracting the calculated deviation from each value to make the sensor data close to the standard data; Linear calibration is expressed in the following form: Calibrated data = a*original data + b; Among them, a is the standard slope and b is the standard intercept.

7. The vehicle-mounted sensor calibration and evaluation method according to claim 2, characterized in that: The evaluation of the calibration effect is to compare and calculate the new response data with the data of the standard instrument, using the mean square error (MS), which is expressed by the following formula: Among them, i represents each measurement point, and n represents the number of measurement points; The accuracy and stability of the sensor are evaluated based on the MSE mentioned above. The higher the accuracy, the smaller the MSE. The stability is evaluated by calculating the standard deviation of the sensor's measurement results at different time points and under the same environmental conditions. The smaller the standard deviation, the better the stability. Through the above data, the response data of the sensor under different gas concentrations, humidity, temperature and ultraviolet light intensity are compared to see whether the response of the sensor is consistent under different environmental conditions and whether the change of the response is consistent with the change of environmental conditions, so as to evaluate the performance of the sensor.

8. The vehicle-mounted sensor calibration and evaluation method according to claim 5, characterized in that: The values ​​of a and b are obtained by linear regression analysis based on the sensor data (X) and the standard data (Y). In the linear regression, the line with the smallest deviation is taken as the result, that is, the solution is Y=aX+b; The resulting slope and intercept (a and b) are applied to the sensor readings to obtain the calibrated sensor data.

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