Pressure Data Compensation Method Based on Temperature Sensor and Underground Water Level Monitoring Device

Abstract

The present invention provides a pressure data compensation method based on a temperature sensor and a groundwater level monitoring device, relating to the technical field of temperature compensation of pressure sensors. The aim is to achieve a pressure sensor that can more reliably and efficiently cope with extremely cold weather, including: obtaining the fluctuation range coefficient of the temperature sensor; respectively obtaining real-time temperature data and real-time pressure data through the temperature sensor and the pressure sensor; obtaining the range of corrected temperature based on the fluctuation range coefficient and the real-time temperature data; obtaining the compensated pressure range through the range of corrected temperature and the real-time pressure data; and selecting the optimal pressure value from the compensated pressure range as the finally compensated pressure value. The present invention has the advantage of improving the data detection accuracy of the pressure sensor in an extremely cold environment.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature compensation of pressure sensors, and more particularly, to a method for compensating pressure data based on a temperature sensor and a groundwater level monitoring device. Background Art

[0002] A pressure sensor is a common device for detecting pressure data and has a wide range of applications.

[0003] However, in the actual use of pressure sensors, they are often tested by the natural environment. For example, in alpine regions, especially in permafrost areas, due to the extremely low surface temperature in winter, the water bodies on the surface and in the shallow underground are prone to freeze. Currently, the commonly used groundwater level monitoring equipment mainly relies on pressure sensors to measure the pressure of water bodies, and then calculates the water level height by inversion. When the water body freezes, its volume expansion will directly affect the pressure measurement result, resulting in inaccurate data or equipment damage, and affecting the accuracy and reliability of monitoring. Traditional solutions usually include simple anti-freezing designs, such as adding thermal insulation layers or using electric heating devices. However, these methods have limited effects in dealing with extremely cold environments and usually come with problems such as high energy consumption and complex maintenance.

[0004] Therefore, it is necessary to design a pressure sensor that can more reliably and efficiently cope with extremely cold weather and improve the accuracy of data detection of pressure sensors in extremely cold environments. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for compensating pressure data based on a temperature sensor and a groundwater level monitoring device, which can more reliably and efficiently cope with extremely cold weather. [[ID=!1]]

[0006] The present invention is achieved through the following technical solutions:

[0007] First, a method for compensating pressure data based on a temperature sensor is provided, including the following steps:

[0008] Obtain the fluctuation range coefficient γ of the temperature sensor;

[0009] Obtain real-time temperature data and real-time pressure data through the temperature sensor and the pressure sensor respectively;

[0010] Obtain the range of corrected temperature, T lb ,T ub being the lower and upper bounds of the range of the corrected temperature respectively;

[0011] Obtain the compensated pressure range through the range of corrected temperature and the real-time pressure data, P lb ,P ub being the lower and upper bounds of the compensated pressure range respectively;

[0012] Select the optimal pressure value from the compensated pressure range as the final compensated pressure value P fi 。

[0013] Preferably, the method for obtaining the fluctuation range coefficient of the temperature sensor is as follows:

[0014] Obtain the accuracy influence parameter ac of the temperature sensor, where the accuracy influence parameter represents the magnitude of the influence of the sensor accuracy on the detected value;

[0015] Obtain the short-term uniformity influence parameter ev of the temperature sensor, where the short-term uniformity influence parameter represents the magnitude of the influence of the change in the sensor value within a certain time on the detected value;

[0016] Obtain the fluctuation range coefficient γ of the temperature sensor:

[0017]

[0018] Preferably, the method for obtaining the accuracy influence parameter ac is as follows:

[0019]

[0020] sa = 0.1 x ;

[0021] where sa is the accuracy value of the temperature sensor, x is the decimal precision digit of the detected value of the temperature sensor, and n is an adjustment constant.

[0022] Preferably, the method for obtaining the short-term uniformity influence parameter ev is as follows:

[0023]

[0024] m ∈ [1, 5];

[0025]

[0026] where ea is an intermediate parameter, m is the duration of short-term sampling of the detected value of the temperature sensor in seconds, N is the total number of short-term sampled detected values of the temperature sensor, and te i is the detected value of the i-th temperature sensor in short-term sampling.

[0027] Preferably, the method for obtaining the corrected temperature range based on the fluctuation range coefficient and the real-time temperature data is as follows:

[0028] T real ∈ [T lb , T ub ;

[0029] Tlb =(1 - γ)*T measure ;

[0030] T ub =(1 + γ)*T measure ;

[0031] wherein, T real is the corrected temperature, and T measure is the real-time temperature data.

[0032] Preferably, the method for obtaining the compensated pressure range from the range of the corrected temperature and the real-time pressure data is as follows:

[0033] P com ∈[P lb , P ub ;

[0034] P lb = P measure *(1 + θ*(T lb - T ref ));

[0035] P ub = P measure *(1 + θ*(T ub - T ref ));

[0036] wherein, P com is the compensated pressure, θ is the empirical compensation coefficient, T ref is the reference temperature, and P measure is the real-time pressure data.

[0037] Preferably, the method for selecting the optimal pressure value from the compensated pressure range as the final compensated pressure value is as follows:

[0038] Continuously obtain a total of J measured values of the pressure sensors within s seconds;

[0039] Respectively obtain the compensated pressure ranges of the J measured values of the pressure sensors;

[0040] Take the intersection of the compensated pressure ranges of the J measured values of the pressure sensors;

[0041] Select the median of the intersection of the compensated pressure ranges as the final compensated pressure value P fi .

[0042] The present invention also provides a groundwater level monitoring device, which applies the pressure data compensation method based on a temperature sensor described in any one of the above, and includes a pressure sensor and a temperature sensor;

[0043] Compensate the real-time pressure data of the pressure sensor through the pressure data compensation method based on the temperature sensor to obtain the finally compensated pressure value;

[0044] Obtain the water level height H based on the finally compensated pressure value:

[0045]

[0046] where ρ(T fi ) represents the water density at temperature T obtained by looking up a table, and g is the acceleration due to gravity. fi

[0047] Preferably, an isolation liquid is filled in the sensing chamber of the pressure sensor, and a flexible diaphragm is arranged between the isolation liquid and the water body. The isolation liquid is used to transfer the pressure of the water body to the sensing surface of the pressure sensor, preventing the pressure sensor from directly contacting the water body.

[0048] Preferably, the outer layer of the pressure sensor is wrapped with a heat-insulating material.

[0049] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0050] The present invention can compensate for the data deviation of the pressure sensor caused by low temperature, improving the accuracy of the detection data of the temperature sensor;

[0051] The present invention performs pressure compensation based on the temperature data of the temperature sensor, taking into account the instability and accuracy limitations of the temperature sensor while processing the temperature data, further improving the accuracy of pressure compensation;

[0052] The pressure sensor of the present invention is convenient to be applied to various devices that need to measure pressure, with a wide range of applications;

[0053] The underground water level monitoring device of the present invention can be applied to extremely cold environments, solving the problem of measurement data errors caused by water body freezing under extremely low temperature conditions, and ensuring that the monitoring device can provide accurate and stable data in harsh environments;

[0054] The present invention is reasonably designed, has a simple structure, and the related data processing is also easy to implement, with high cost performance. Description of the Drawings

[0055] Figure 1 It is a schematic flow chart of the pressure data compensation method based on the temperature sensor provided in Embodiment 1 of the present invention;

[0056] Figure 2 It is a schematic structural diagram of the case of setting the isolation liquid and the flexible diaphragm of the underground water level monitoring device provided in Embodiment 2 of the present invention; ​

[0057] Icons: 101 - Pressure sensor, 102 - Housing, 103 - Water body, 104 - Flexible diaphragm, 105 - Thermal insulation material, 106 - Isolation liquid. Specific implementation mode

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0059] Embodiment 1

[0060] This embodiment provides a pressure data compensation method based on a temperature sensor. Refer to Figure 1 , including the following steps:

[0061] Obtain the fluctuation range coefficient γ of the temperature sensor;

[0062] Obtain real-time temperature data and real-time pressure data through the temperature sensor and the pressure sensor respectively;

[0063] Obtain the range of the corrected temperature T based on the fluctuation range coefficient and the real-time temperature data, lb , T ub are respectively the lower bound and the upper bound of the range of the corrected temperature;

[0064] Obtain the compensated pressure range through the range of the corrected temperature and the real-time pressure data, P lb , P ub are respectively the lower bound and the upper bound of the compensated pressure range;

[0065] Select the optimal pressure value from the compensated pressure range as the finally compensated pressure value P fi .

[0066] In this embodiment, the method for obtaining the fluctuation range coefficient of the temperature sensor is:

[0067] Obtain the accuracy influence parameter ac of the temperature sensor, and the accuracy influence parameter represents the influence magnitude of the sensor accuracy on the detected value;

[0068] Obtain the short-term uniformity influence parameter ev of the temperature sensor, and the short-term uniformity influence parameter represents the influence magnitude of the change in the sensor value within a certain period of time on the detected value;

[0069] Obtain the fluctuation range coefficient γ of the temperature sensor:

[0070]

[0071] The fluctuation range coefficient represents the data accuracy of the temperature sensor. The larger the fluctuation range coefficient, the lower the accuracy of the temperature sensor. Therefore, an error situation is considered around the actual detected value to obtain a temperature value range, that is, the larger the fluctuation range coefficient, the larger this temperature value range.

[0072] Further, the method for obtaining the accuracy influence parameter ac is as follows:

[0073]

[0074] sa = 0.1 x ;

[0075] Wherein, sa is the accuracy value of the temperature sensor, x is the decimal precision digit of the detected value of the temperature sensor, n is an adjustment constant, and n can take 2 - 3 in practical applications. For example, the decimal precision digit of the detected value of the temperature sensor is 1 digit after the decimal point, that is, for example, its accuracy can monitor -10.5 degrees. Here, n takes 2, then

[0076] On the other hand, the method for obtaining the short-term uniformity influence parameter ev is as follows:

[0077]

[0078] m ∈ [1, 5];

[0079]

[0080] Wherein, ea is an intermediate parameter, m is the duration of short-term sampling of the detected value of the temperature sensor and the unit is seconds, N is the total number of short-term sampling of the detected value of the temperature sensor, and te i is the detected value of the i-th temperature sensor for short-term sampling.

[0081] It should be particularly noted that the short-term uniformity influence parameter is mainly obtained by continuous sampling within a relatively short time. The possible magnitude of the detection error is judged by the stability of the sensor value. The more unstable it is, the larger the short-term uniformity influence parameter, which means there will be a larger error. Finally, the range for correcting the real-time temperature data obtained is also larger. m can take 2 - 5 seconds, and N can take 10 - 20 times. The calculation of the short-term uniformity influence parameter does not need to be updated continuously. An update period can be set to detect, calculate, and update the short-term uniformity influence parameter of the temperature sensor and store it. It can be directly applied every time actual measurement is carried out.

[0082] Based on this, the method for obtaining the range of the corrected temperature based on the fluctuation range coefficient and the real-time temperature data is as follows:

[0083] T real ∈[T lb ,T ub ;

[0084] T lb =(1 - γ)*T measure ;

[0085] T ub =(1 + γ)*T measure ;

[0086] Among them, T real is the corrected temperature, and T measure is the real-time temperature data. This step is to expand the range according to the size of the fluctuation range coefficient on the real-time temperature data. As calculated before, the larger the fluctuation range coefficient, the greater the possible error of the temperature sensor.

[0087] Next, the method for obtaining the compensated pressure range through the range of the corrected temperature and the real-time pressure data is as follows:

[0088] P com ∈[P lb ,P ub ;

[0089] P lb =P measure *(1 + θ*(T lb -T ref ));

[0090] P ub =P measure *(1 + θ*(T ub -T ref ));

[0091] Among them, P com is the compensated pressure, θ is the empirical compensation coefficient, T ref is the reference temperature, and P measure is the real-time pressure data.

[0092] Finally, the method for selecting the optimal pressure value from the compensated pressure range as the final compensated pressure value is as follows:

[0093] Continuously obtain a total of J measured values of the pressure sensors within s seconds;

[0094] Respectively obtain the compensated pressure ranges of the J measured values of the pressure sensors;

[0095] Take the intersection of the compensated pressure ranges of the measured values of J of the pressure sensors;

[0096] Select the median of the intersection of the compensated pressure ranges as the final compensated pressure value P fi . Continuously collect the measured values of multiple pressure sensors, select the range that all measured values have in common among the compensated pressure ranges of all measured values, and eliminate the ranges that are not in common, that is, regard the ranges that are not in common as having relatively large errors. Specifically, when implementing, s can be taken as 2 - 10 seconds, and J can be taken as 10 - 30.

[0097] Embodiment 2

[0098] The present invention also provides a groundwater level monitoring device, which applies any one of the above-mentioned pressure data compensation methods based on a temperature sensor, and includes a pressure sensor and a temperature sensor;

[0099] Based on the temperature sensor, compensate the real-time pressure data of the pressure sensor through the pressure data compensation method to obtain the final compensated pressure value;

[0100] Obtain the water level height H based on the final compensated pressure value:

[0101]

[0102] Where ρ(T fi ) represents the water density at a temperature of T obtained by looking up a table, and g is the acceleration due to gravity. fi

[0103] In this embodiment, for an example, reference can be made to Figure 2 , an isolation liquid 106 is filled in the sensing chamber of the pressure sensor 101, and a flexible diaphragm 104 is provided between the isolation liquid 106 and the water body 103. The isolation liquid 106 is used to transmit the pressure of the water body 103 to the sensing surface of the pressure sensor 101, so as to prevent the pressure sensor 101 from directly contacting the water body 103. The isolation liquid 106 can adopt silicone oil (such as -50°C antifreeze silicone oil). The flexible diaphragm 104 can be made of fluororubber, which has excellent low-temperature elasticity and pressure resistance, can still maintain good flexibility in an environment of -60°C, and can effectively transmit pressure.

[0104] Furthermore, the outer layer of the pressure sensor 101 is wrapped with a thermal insulation material 105. The main thermal insulation layer is a polyurethane foam with a thickness of 2 cm, and its thermal conductivity is lower than 0.025 W / m·K, effectively isolating the external low temperature. An aluminum foil heat insulation film is further coated on the outer layer to reduce heat loss. This design of the thermal insulation material 105 can ensure that even in an extreme low temperature of -50°C, the temperature inside the pressure sensor 101 can still be maintained within a suitable working range, ensuring the stability of measurement data.

[0105] When implementing specifically, a stainless-steel pressure sensor 101 with the model PSS-316L can be selected. This sensor has good corrosion resistance and low-temperature resistance, and is suitable for working in an alpine environment for a long time. The measurement range of this pressure sensor 101 is 0 - 2 MPa, which can cover the water level measurement in the water depth range of 0 to 20 meters. The resolution of the sensor is 0.1 kPa, and the temperature working range is -50°C to 85°C.

[0106] On the other hand, the housing 102 of this device can be made of titanium alloy material. Titanium alloy has extremely high cold resistance and corrosion resistance, ensuring the long-term stable operation of the sensor in a harsh environment. In addition, the titanium alloy housing 102 also has relatively high mechanical strength and can withstand the pressure of the external frozen soil layer. The presence of the housing 102 does not affect the normal operation of the pressure sensor 101 because the sensor contacts the external water body 103 through a flexible diaphragm 104, and the pressure signal is transmitted through the diaphragm to the isolation liquid 106 inside the sensor and then to the sensing surface of the sensor. Since the diaphragm has sufficient elasticity, it can deform freely under the protection of the housing 102, thus ensuring the effective transmission of pressure.

[0107] When installing the groundwater level monitoring device, the reasonable installation depth can be selected according to the depth of the frozen soil layer, the annual change range, and the specific requirements of the monitoring target, ensuring that the sensor avoids the seasonal frozen layer and does not affect the normal measurement of groundwater; it can also be installed at an angle of 30 - 45 degrees. At this time, the vertical pressure of the relevant sensor on the frozen layer is greatly reduced, effectively reducing the measurement error and the risk of equipment damage caused by freezing.

[0108] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A pressure data compensation method based on a temperature sensor, characterized in that It includes the following steps: Obtain the fluctuation range coefficient γ of the temperature sensor; Obtain the real-time temperature data and real-time pressure data through the temperature sensor and the pressure sensor respectively; Obtain the range of the corrected temperature, T, based on the fluctuation range coefficient and the real-time temperature data lb , T ub are the lower bound and the upper bound of the range of the corrected temperature, respectively; Obtain the compensated pressure range, P, based on the range of the corrected temperature and the real-time pressure data lb , P ub are the lower bound and the upper bound of the compensated pressure range, respectively Select the optimal pressure value from the compensated pressure range as the final compensated pressure value P fi ; The method for obtaining the fluctuation range coefficient of the temperature sensor is: Obtain the accuracy influence parameter ac of the temperature sensor, and the accuracy influence parameter represents the influence degree of the sensor accuracy on the detected value; Obtain the short-term uniformity influence parameter ev of the temperature sensor, and the short-term uniformity influence parameter represents the influence degree of the change of the sensor value within a certain time on the detected value; Obtain the fluctuation range coefficient γ of the temperature sensor: The method for obtaining the accuracy influence parameter ac is: sa = 0.1 x ; Wherein, sa is the accuracy value of the temperature sensor, x is the decimal precision digit of the detected value of the temperature sensor, and n is an adjustment constant; The method for obtaining the short-term uniformity influence parameter ev is: m∈[1,5]； Among them, ea is an intermediate parameter, m is the duration of short-term sampling of the detection value of the temperature sensor in seconds, N is the total number of detection values of the temperature sensor for short-term sampling, and te i is the detection value of the i-th temperature sensor for short-term sampling.

2. The pressure data compensation method based on a temperature sensor according to claim 1, wherein, The method for obtaining the range of the corrected temperature based on the fluctuation range coefficient and the real-time temperature data is: T real ∈ [T lb , T ub ; T lb =(1 - γ)*T measure ; T ub = (1 + γ) * T measure ; Among them, T real is the corrected temperature, and T measure is the real-time temperature data.

3. A pressure data compensation method based on a temperature sensor according to claim 2, characterized in that, The method for obtaining the compensated pressure range through the range of the corrected temperature and the real-time pressure data is: P com ∈ [P lb , P ub ; Among them, P com is the compensated pressure, is the empirical compensation coefficient, T ref is the reference temperature, P measure is the real-time pressure data.

4. A pressure data compensation method based on a temperature sensor according to claim 1, characterized in that The method for selecting the optimal pressure value from the compensated pressure range as the finally compensated pressure value is: Continuously obtain a total of J measured values of the pressure sensor within s seconds; Respectively obtain the compensated pressure ranges of the J measured values of the pressure sensor; Take the intersection of the compensated pressure ranges of the J measured values of the pressure sensor; Select the median of the intersection of the compensated pressure ranges as the final compensated pressure value P fi .

5. An underground water level monitoring device, applying a pressure data compensation method based on a temperature sensor as described in any one of claims 1-4, characterized in that, It includes a pressure sensor and a temperature sensor; Based on the temperature sensor, compensate the real-time pressure data of the pressure sensor through the pressure data compensation method to obtain the finally compensated pressure value; Obtain the water level height H based on the finally compensated pressure value: where ρ(T fi ) represents the water density at temperature T obtained by looking up a table, and g is the acceleration due to gravity. fi ​ 6. The groundwater level monitoring device according to claim 5, characterized in that, The sensing chamber of the pressure sensor is filled with an isolation liquid, and a flexible diaphragm is arranged between the isolation liquid and the water body. The isolation liquid is used to transmit the pressure of the water body to the sensing surface of the pressure sensor to prevent the pressure sensor from directly contacting the water body.

7. The groundwater level monitoring device according to claim 5, characterized in that, The outer layer of the pressure sensor is wrapped with a heat-insulating material.

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