A high-precision pH sensor control system and method applicable to mobile platforms

Abstract

The present invention discloses a high-precision pH sensor control system and method applicable to a mobile platform, which includes a main controller, an acceleration sensor electronic compass module, a pressure sensor module, an LED module, a photodiode module, a flowmeter module, a reagent pump and sample pump drive module, an SD card storage module, a Bluetooth communication module, and a power management module. The acceleration sensor electronic compass module, the pressure sensor module, the LED module, the photodiode module, the flowmeter module, the reagent pump and sample pump drive module, the SD card storage module, the Bluetooth communication module, and the power management module are all connected to the main controller. The control system is installed on the mobile platform, and reagents and seawater are pumped in proportion according to the moving speed of the mobile platform for pH detection, and pressure correction is performed on the detected pH. The present invention can achieve real-time high-precision detection of the pH of seawater during the high-speed movement of the mobile platform.

Description

Technical Field

[0001] The present invention relates to the field of marine monitoring, and in particular to a high-precision pH sensor control system and method applicable to a mobile platform. Background Art

[0002] The pH value of seawater is one of the important parameters for quantitatively describing the chemical characteristics of the ocean and is of great significance for studying seawater acidification and the carbon cycle. Currently, the mainstream pH sensors are of two types: the electrode method and the photometric method. The electrode method sensor can be used on a mobile platform, but its accuracy is relatively low and it cannot truly reflect the process of seawater acidification; the photometric pH sensor can achieve high-precision detection of seawater acidification, but each detection takes at least 5 minutes at the fastest, which cannot meet the requirements of rapid real-time measurement on a mobile platform. In view of the current problems, a high-precision pH sensor control system and method applicable to a mobile platform are proposed. Summary of the Invention

[0003] In order to overcome the above problems existing in the prior art, the present invention proposes a high-precision pH sensor control system and method applicable to a mobile platform.

[0004] The technical solution adopted by the present invention to solve its technical problems is: a high-precision pH sensor control system applicable to a mobile platform, including a main controller, an acceleration sensor electronic compass module, a pressure sensor module, an LED module, a photodiode module, a flow meter module, a reagent pump and sample pump drive module, an SD card storage module, a Bluetooth communication module, and a power management module. The acceleration sensor electronic compass module, the pressure sensor module, the LED module, the photodiode module, the flow meter module, the reagent pump and sample pump drive module, the SD card storage module, the Bluetooth communication module, and the power management module are all connected to the main controller;

[0005] The acceleration sensor electronic compass module is used to obtain the attitude and direction of the sensor during the movement of the mobile platform;

[0006] The pressure sensor module is used to obtain the underwater depth where the sensor is located during the movement of the mobile platform;

[0007] The LED module and the photodiode module are used to obtain the absorbance of seawater for calculating the pH of seawater;

[0008] The reagent pump and sample pump drive module is used to pump seawater samples and reagents into the mixing flow cell and simultaneously synchronously adjust the pump speeds of the reagent pump and the sample pump according to the movement speed of the mobile platform.

[0009] The above-mentioned high-precision pH sensor control system applicable to a mobile platform further includes a reserved communication module. The reserved communication module is connected to the main controller and is used for the sensor to communicate with a computer by means of a wired connection, or for connecting to the communication interface of the mobile platform and connecting an external sensor.

[0010] The above-mentioned high-precision pH sensor control system applicable to a mobile platform further includes a GPS positioning module. The GPS positioning module is connected to the main controller and is used for providing the position information of the sensor placement.

[0011] The control method of the above-mentioned high-precision pH sensor control system applicable to a mobile platform includes the following steps:

[0012] Step 1: Install the pH sensor control system on the mobile platform, connect it to the operation terminal through the Bluetooth communication module, set the initial working mode and initial parameters through the operation terminal, store the initial working mode and initial parameters, disconnect the connection between the Bluetooth communication module and the operation terminal, and establish a connection with the mobile platform;

[0013] Step 2: After the mobile platform enters the water, the main controller collects and stores the data of the acceleration sensor electronic compass module and the pressure sensor module;

[0014] Step 3: The main controller collects the photodiode signal I when the LED is off, controls the sample pump to pump seawater samples into the flow cell, turns on the LED and collects the photodiode signal I at this time, and stores the above two signals into the SD card storage module; d and stores the above two signals into the SD card storage module; r and stores the above two signals into the SD card storage module;

[0015] Step 4: The mobile platform communicates with the pH sensor control system through the Bluetooth communication module, and sets the working time intervals of the acceleration sensor electronic compass module and the pressure sensor module and the flow rates of the sample pump and the reagent pump according to the type and working mode of the mobile platform;

[0016] Step 5: During the movement of the mobile platform, the main controller controls the sample pump to pump seawater samples into the flow cell, and at the same time the reagent pump pumps the reagent into the flow cell according to the flow rate set in Step 4, turns on the LED, and collects the photodiode signal I, and stores I into the SD card storage module; m stores I into the SD card storage module; m stores I into the SD card storage module;

[0017] Step 6: Combining I obtained in Step 3, I, and I obtained in Step 5, considering the change in water depth when the pH sensor moves with the mobile platform, the pH calculation formula after pressure correction is: d I, r I, m I, considering the change in water depth when the pH sensor moves with the mobile platform, the pH calculation formula after pressure correction is: c Calculation formula:

[0018]

[0019] Among them, pH 0 represents the pH before pressure correction, pH 0 = c 0 + c 1 A + c 2 A 2 + c 3 A 3 + c 4 A 4 + c 5 A s ; A represents absorbance, D represents the depth of the pH sensor control system, c 0 , c 1 , c 2 , c 3 , c 4 , c 5 , d 0 , d 1 , d 2 , d 3 are all coefficients, obtained through experimental determination;

[0020] Step 7, calculate the position of the pH sensor control system in real time during the movement process, and repeat steps 3 - 6 to obtain the pH at different depths and positions during the entire movement process of the mobile platform.

[0021] The above - mentioned control method for a high - precision pH sensor control system applicable to a mobile platform, the types of the mobile platform in step 4 include but are not limited to profile buoys, AUVs, and Gliders.

[0022] The above - mentioned control method for a high - precision pH sensor control system applicable to a mobile platform, the working modes in step 4 include but are not limited to the full - process continuous working mode, the diving - process working mode, and the surfacing - process working mode.

[0023] The above - mentioned control method for a high - precision pH sensor control system applicable to a mobile platform, the calculation process of the flow rates of the sample pump and the reagent pump in step 4 specifically includes:

[0024] Step 4.1, the main controller calculates the vertical speed of the sensor by using the method of regularly collecting data from the pressure sensor, and calculates the actual moving speed of the sensor according to the angle between the mobile platform and the horizontal plane when moving;

[0025] Step 4.2, calculate the flow rate Q 海水 of the seawater pump according to the actual moving speed obtained in step 4.1, and the specific technical formula is as follows:

[0026] Q 海水 = a·v 实际 + b

[0027] where a and b are both parameters, a is determined by the motion speed range of the mobile platform, and b is determined by the seawater pump flow rate range;

[0028] Step 4.3, according to the seawater pump flow rate Q obtained in Step 4.2 海水 calculate the reagent pump flow rate Q 试剂 , and the specific calculation formula is as follows:

[0029]

[0030] where k is a proportionality coefficient.

[0031] The above control method of a high-precision pH sensor control system applicable to a mobile platform, the specific content of Step 7 for calculating the position in real time during the movement of the pH sensor control system includes:

[0032] Step 7.1, according to the fixed volume of the detection flow path detected by the seawater pump flowmeter, calculate the time t required for seawater to completely fill the detection flow path from the start 流路 , and at the same time, according to the optoelectronic detection circuit and the ADC sampling circuit, the sampling time t can be comprehensively obtained 采样 to obtain the total time t for the sensor to acquire data 总 = t 流路 + t 采样 ;

[0033] Step 7.2, decompose the actual moving speed of the sensor obtained in Step 4.1 into the moving speeds v x , v y , v z in the three directions of OX, OY, and OZ, and obtain the moving distance E of the sensor relative to the initial point o(x 0 , y 0 , z 0 ), and the calculation formula is: n The calculation formula is:

[0034] where E 0 is the distance coordinate of the initial point O, i represents the i-th acquisition of position information, and n represents the n-th acquisition of position information.

[0035] The beneficial effect of the present invention is that the present invention overcomes the problem of slow detection time of the current photometric sensor, greatly shortens the detection time, improves the detection accuracy of seawater pH, and can realize real-time high-precision detection of seawater pH during the high-speed movement of the mobile platform. Description of the Drawings

[0036] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0037] Figure 1 It is a schematic diagram of the pH sensor control system according to an embodiment of the present invention;

[0038] Figure 2 It is a flowchart of the pH sensor control method according to an embodiment of the present invention;

[0039] Figure 3 It is a schematic diagram of the sensor carried by the Glider during the diving operation according to an embodiment of the present invention. Specific embodiments

[0040] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0041] As Figure 1 shown, this embodiment discloses a high-precision pH sensor control system applicable to a mobile platform, including a main controller, an acceleration sensor electronic compass circuit, a pressure sensor circuit, an LED circuit, a photodiode circuit, a flowmeter circuit, a reagent pump and sample pump drive circuit, an SD card storage circuit, a Bluetooth communication circuit, a GPS positioning circuit, a reserved communication circuit, and a power management circuit.

[0042] The main controller is the core of the control system. An STM32L series high-speed and low-power single-chip microcomputer from ST company is selected as the controller, which is equipped with an 8M crystal oscillator circuit, a 32.768k real-time clock circuit, a system reset circuit, and a program download circuit. The acceleration sensor and electronic compass circuit are connected to the main controller through the SPI interface; the pressure sensor outputs a voltage signal, which is connected to a high-precision 16-bit ADC circuit through a signal amplification and filtering circuit composed of operational amplifiers to convert the analog voltage signal into a digital voltage signal, and the ADC is connected to the main controller through the SPI interface; similarly, the photodiode outputs a current signal, which is converted into a voltage signal through an operational amplifier, and then the voltage signal passes through an amplification and filtering circuit and is connected to a high-precision 16-bit ADC circuit to convert the analog voltage signal into a digital voltage signal, and the ADC is connected to the main controller through the SPI interface; the LED is connected to the main controller through its drive circuit, and the drive circuit is mainly composed of a constant current source chip, aiming to accurately control the LED drive current at 20mA, with an accuracy generally not exceeding 1%, to ensure the stability of the LED light source brightness and further ensure the accuracy of pH detection. The main controller controls the on / off of the LED drive circuit through GPIO, and further controls the on / off of the LED light source; the flowmeter outputs a voltage signal, which is connected to a high-precision 16-bit ADC circuit through a signal amplification and filtering circuit composed of operational amplifiers to convert the analog voltage signal into a digital voltage signal, and the ADC is connected to the main controller through the SPI interface; the reagent pump and sample pump drive circuit consists of an integrated stepper motor drive chip and peripheral circuits. The main controller outputs a PWM signal with a certain frequency to the drive circuit through the GPIO pin to adjust the speed of the pump, thereby adjusting the sample or reagent flow rate; the SD card storage circuit is connected to the main controller through the SDIO interface to achieve fast data reading and writing. The files create folders based on the date and internally store data such as pH measured by the sensor in real time; the Bluetooth communication circuit is connected to the main controller through the USART interface to achieve interconnection with mobile phones, computers, and mobile platforms; the GPS positioning circuit is connected to the main controller through the USART interface to achieve sensor position acquisition, clock information correction, and navigation backup; the reserved communication circuit is connected to the main controller through the USART interface to achieve a wired connection with a computer or mobile platform, or connect to external sensors such as CTD to achieve pH data compensation and correction; the power management circuit mainly converts the external +12V or +24V DC power of the sensor into the required +5V or +3.3V voltage of the device, and controls the on / off of different circuits according to the actual working conditions to reduce the overall power consumption of the system.

[0043] Such as Figure 2As shown in the figure, this embodiment also discloses a high-precision pH sensor control method applicable to mobile platforms. The specific implementation method is to install the sensor on underwater mobile platforms such as profile buoys, AUVs, or Gliders through a special fixture, connect to the platform power supply interface, and the sensor powers on automatically. Connect to the sensor via Bluetooth on a mobile phone or computer, set the initial working mode, working interval, sample pump and reagent pump speeds, etc. After completion, the sensor obtains the deployment station position information through GPS, calibrates the instrument clock, and stores the initially set working parameters and position information tagged with time in the internal SD card; disconnect the connection between the sensor and the mobile phone or computer, and establish communication with underwater mobile platforms such as profile buoys, AUVs, or Gliders via Bluetooth.

[0044] After the sensor is deployed into the water together with the mobile platform, the main controller reads the data of the acceleration sensor and electronic compass, obtains the data of the pressure sensor, and stores the data tagged with time in the internal SD card; the main controller collects the photodiode signal I when the LED is off through a high-precision ADC d , then controls the sample pump to pump seawater samples into the flow cell, turns on the LED through the LED drive circuit, and collects the photodiode signal I r , and stores I d and I r into the SD card; the mobile platform sends a working instruction to the sensor, sets new working parameters according to the actual situation, and the working mode is divided into profile buoy, Glider slow mode, and AUV fast mode according to different carriers; according to the working stage, it can be divided into full-course continuous working mode, diving process working mode, and surfacing process working mode; the working interval, sample pump, and reagent pump speeds are different under different working modes. When working in the full-course continuous working mode, the sensor is powered on throughout the process and automatically adjusts the pump speed according to the type of mobile platform. When working in the diving process working mode, the sensor powers on and works during the diving process of the mobile platform, and enters the sleep mode during the surfacing process to reduce power consumption. When working in the surfacing process working mode, the sensor powers on and works during the surfacing process of the mobile platform, and enters the sleep mode during the diving process to reduce power consumption.

[0045] Taking the sensor mounted on a Glider and working during the diving process as an example, establish a motion coordinate system O-XYZ, with OX pointing north, OY pointing east, and OZ pointing to the ground, as Figure 3 shown. The motion speeds in the three directions are v x , v y , v z . The sensor moves from point O to point A, the angle between the motion direction and the XOY plane is α, the angle between the motion direction and the YOZ plane is β, and the angle between the motion direction and the XOZ plane is γ. The actual motion speed of the sensor is v 实际 , then there is:

[0046]

[0047] The glider dives at a certain dive angle. As Figure 3 shown, the main controller collects the data of the pressure sensor every 10 s through the ADC, and calculates the vertical diving speed. The calculation method is as follows:

[0048]

[0049] In the formula, T 压力 is the time interval for collecting data by the pressure sensor, D O , D B are the depths of points O and B respectively, and v 垂直 is the vertical speed of the sensor. In this embodiment, D B = 100 m, D O = 105 m. Then the vertical diving speed is:

[0050]

[0051] At the same time, the main controller reads the data of the acceleration sensor through the SPI interface, and obtains that the dive angle α of the glider is 30°. Then the calculation method of the actual movement speed of the sensor is:

[0052]

[0053] The main controller reads the data of the electronic compass through the SPI interface, and obtains that the heading angle of the glider is 45°, that is, β, γ is 45°. Then it can be obtained that:

[0054]

[0055] Then, according to v 实际 to control the speed of the seawater pump, and further the flow rate Q 海水 of the seawater pump can be controlled. The calculation method is as follows:

[0056] Q 海水 = 70·v 实际 + 350

[0057] The flow rate range of the seawater pump is 350 ml / min - 560 ml / min, and the speed of the mobile platform is 0 - 3 m / s. Then the coefficients 70 and 350 can be calculated.

[0058] The flow rate Q 试剂 of the corresponding reagent pump can be obtained by calculating according to a fixed ratio with the seawater sample:

[0059]

[0060] Generally, it is necessary to find the optimal coefficient k through experiments. When using standard seawater, the absorbance is fixed after adding the reagent, so the corresponding photodiode signal I t0 is also fixed. For example, first take k = 1500. The main controller simultaneously controls the seawater pump and the reagent pump to pump the sample, turns on the LED through the LED drive circuit, and collects the photodiode signal I t1 , and compare the magnitude of I t1 with I t0 . If I t1 > I t0 , then select k as half of the original value, that is, k = 750. The main controller simultaneously controls the seawater pump and the reagent pump to pump the sample, turns on the LED through the LED drive circuit, and collects the photodiode signal I t2 ; compare the magnitude of I t2 with I t0 . If I t2 < I t0 , then take k as half of the sum of the left and right boundary values, that is, k = 1125. The main controller simultaneously controls the seawater pump and the reagent pump to pump the sample, turns on the LED through the LED drive circuit, and collects the photodiode signal I t3 ; compare the magnitude of I t3 with I t0 . If I t3 ≈ I t0 , then the value of the proportionality coefficient k can be determined. If they are not close, the above method can be repeatedly used to obtain the optimal proportionality coefficient k.

[0061] By fixing the volume V of the flow rate and the detection flow path, the time t for the seawater to be pumped into the detection flow path from the start until it is completely filled can be calculated 流路 , and the calculation method is as follows:

[0062]

[0063] At the same time, according to the photoelectric detection circuit and the ADC sampling circuit, the sampling time t 采样 can be comprehensively obtained. Then the total time for the sensor to obtain data is:

[0064] t 总 = t 流路 + t 采样 = 0.1s + 0.005s = 0.105s

[0065] Then the distance that the sensor moves along with the moving platform from the start of pumping the seawater sample into the detection flow path until the detection data is obtained is:

[0066] s = v 实际 · t 总 = 1 · 0.105 = 0.105m

[0067] Then the moving distance in each direction is:

[0068]

[0069] Then the position A of the sensor relative to the initial point O(x 0 , y 0 , z 0 ) after movement can be approximated as:

[0070]

[0071] When the sensor measures during the movement of the mobile platform, the main controller controls the sample pump to pump seawater samples into the flow cell, and at the same time, the reagent pump pumps reagents into the flow cell in proportion, and then turns on the LED through the LED drive circuit to collect the photodiode signal I m , and calculate the absorbance Then the pH calculation method is:

[0072] PH 0 = c 0 + c 1 A + c 2 A 2 + c 3 A 3 + c 4 A 4 + c 5 A 5

[0073] Considering that the pH sensor moves with the mobile platform and the water depth is changing, and the corresponding pressure will have a certain impact on the pH calculation, then the pH calculation method after pressure correction is:

[0074]

[0075] Finally, the corrected pH c , the pH before correction 0 , the photodiode signals I d 、I r 、I m 、the position E of the mobile platform n , the attitude angles α, β, γ, and the depth D are stored in the SD card with time as the label for easy later data acquisition and verification reference.

[0076] For the pH calculation method pH 0 = c 0 + c 1 A + c 2 A 2 + c 3 A 3 + c 4 A 4+c 5 A 5 For each coefficient in, a calibration experiment was carried out in the laboratory. The process is as follows: The main controller collects the photodiode signal I when the LED is off through a high-precision ADC d , then controls the sample pump to pump the pH standard solution into the flow cell, turns on the LED through the LED drive circuit, and collects the photodiode signal I r , then the reagent pump pumps the reagent into the flow cell according to a pre-determined ratio, then turns on the LED through the LED drive circuit, and collects the photodiode signal I m , and calculates the absorbance Repeat the above process using another 5 concentrations of pH standard solutions to obtain a system of equations composed of 6 equations, and the coefficient c can be obtained by analysis 0 ~c 5 . For example, using a total of 6 pH standard solutions of 7.5465, 7.8492, 8.1518, 8.3181, 8.4455, and 8.6559, the absorbances of 0.305, 0.269, 0.212, 0.183, 0.164, and 0.132 can be obtained respectively. Then there is the following system of equations:

[0077]

[0078] Solving the system of equations gives:

[0079]

[0080] Then there is:

[0081] pH 0 = 3.16107 + 148.77316A - 1458.19110A 2 + 6541.92447A 3 - 13942.39797A 4 + 11252.30216A 5

[0082] Regarding the pH calibration method Put the pH standard solution in the pressure vessel, put the pH sensor in the pressure vessel, connect the sensor to the computer via Bluetooth, control the pressure change of the pressure vessel, fix the pressure at 4 pressure points respectively, and obtain the pH value and pressure value D measured by the sensor at each pressure point. Finally, a system of equations composed of 4 equations is obtained, and the coefficient d can be obtained by analysis 0 ~d 3 . For example, using a standard solution with a pH value of 8.0512, control the pressure vessel at water depths of 0 km, 0.25 km, 0.5 km, and 1 km respectively to carry out the pressure calibration test. Then there is the following system of equations:

[0083]

[0084] The solution of the system of equations gives:

[0085]

[0086] Then there is:

[0087]

[0088] Import the above calibration coefficients into the sensor via Bluetooth. When the sensor is working in actuality, by measuring the absorbance A and depth D at different times and then substituting them into the calibration formula, the calibrated pH value can be automatically calculated and output.

[0089] Repeat the above steps, and the pH value curves at different positions and different depths of the entire route from when the mobile platform enters the water until it stops moving can be measured, realizing real-time high-precision detection of the pH of seawater during the high-speed movement of the mobile platform.

[0090] The above embodiments are only exemplary embodiments of the present invention and are not used to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present invention, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present invention.

Claims

1. A high-precision pH sensor control system applicable to mobile platforms, characterized in that: it includes a main controller, an acceleration sensor electronic compass module, a pressure sensor module, an LED module, a photodiode module, a flowmeter module, a reagent pump and sample pump drive module, an SD card storage module, a Bluetooth communication module, and a power management module. The acceleration sensor electronic compass module, the pressure sensor module, the LED module, the photodiode module, the flowmeter module, the reagent pump and sample pump drive module, the SD card storage module, the Bluetooth communication module, and the power management module are all connected to the main controller; the acceleration sensor electronic compass module is used to obtain the sensor attitude and direction during the movement of the mobile platform; the pressure sensor module is used to obtain the underwater depth of the position where the sensor is located during the movement of the mobile platform; the LED module and the photodiode module are used to obtain the seawater absorbance for calculating the seawater pH; the reagent pump and sample pump drive module is used to pump seawater samples and reagents to the mixing flow cell, and simultaneously adjust the pump speeds of the reagent pump and the sample pump synchronously according to the movement speed of the mobile platform; Set the working time intervals of the acceleration sensor electronic compass module and the pressure sensor module, and the flow rates of the sample pump and the reagent pump according to the type and working mode of the mobile platform.

2. A high-precision pH sensor control system applicable to mobile platforms according to claim 1, characterized in that, it further includes a reserved communication module. The reserved communication module is connected to the main controller. The reserved communication module is used for the sensor to communicate with a computer by means of a wired connection, or for connecting to the communication interface of the mobile platform and connecting to an external sensor.

3. A high-precision pH sensor control system applicable to mobile platforms according to claim 1, characterized in that, it further includes a GPS positioning module. The GPS positioning module is connected to the main controller. The GPS positioning module is used to provide the position information of the sensor placement.

4. A control method for a high-precision pH sensor control system applicable to mobile platforms according to any one of claims 1-3, characterized in that, it includes the following steps: Step 1, install the pH sensor control system on the mobile platform, connect it to the operation terminal through the Bluetooth communication module, set the initial working mode and initial parameters through the operation terminal, store the initial working mode and initial parameters, disconnect the Bluetooth communication module from the operation terminal, and establish a connection with the mobile platform; Step 2, after the mobile platform enters the water, the main controller collects and stores the data of the acceleration sensor electronic compass module and the pressure sensor module; Step 3, the main controller collects the photodiode signal I when the LED is off d , controls the sample pump to pump seawater samples into the flow cell, turns on the LED and collects the photodiode signal I at this time r , and stores the above two signals into the SD card storage module; Step 4, the mobile platform communicates with the pH sensor control system through the Bluetooth communication module, and sets the working time intervals of the acceleration sensor electronic compass module and the pressure sensor module, and the flow rates of the sample pump and the reagent pump according to the type and working mode of the mobile platform; Step 5, during the movement of the mobile platform, the main controller controls the sample pump to pump seawater samples into the flow cell, and at the same time, the reagent pump pumps the reagent into the flow cell according to the flow rate set in Step 4. Turn on the LED and collect the photodiode signal I m , and store I m into the SD card storage module; Step 6, combine I obtained in Step 3 d , I r , and I obtained in Step 5 m , considering the change in water depth when the pH sensor moves with the mobile platform, after pressure correction , the calculation formula is: Among them, pH 0 represents the pH before pressure correction, ; A represents the absorbance, ; D represents the depth of the pH sensor control system, c 0 、c 1 、c 2 、c 3 、c 4 、c 5 、d 0 、d 1 、d 2 、d 3 are all coefficients obtained through experimental determination; Step 7, calculate the position of the pH sensor control system during the movement in real time, repeat steps 3-6, and obtain the pH values at different depths and positions during the entire movement process of the mobile platform.

5. The control method of a high-precision pH sensor control system applicable to a mobile platform according to claim 4, characterized in that, the types of the mobile platform in step 4 include but are not limited to profile floats, AUVs, and Gliders.

6. The control method of a high-precision pH sensor control system applicable to a mobile platform according to claim 4, characterized in that, the working modes in step 4 include a full-course continuous working mode, a diving process working mode, and a surfacing process working mode.

7. The control method of a high-precision pH sensor control system applicable to a mobile platform according to claim 4, characterized in that, the calculation process of the flow rates of the sample pump and the reagent pump in step 4 specifically includes: Step 4.1, the main controller calculates the vertical speed of the sensor by means of regularly collecting the data of the pressure sensor, and calculates the actual moving speed of the sensor according to the size of the angle between the mobile platform and the horizontal plane during movement; Step 4.2: Calculate the flow rate of the seawater pump based on the actual moving speed obtained in Step 4.1 , and the specific technical formula is as follows: wherein, both a and b are parameters, a is determined by the movement speed range of the mobile platform, and b is determined by the seawater pump flow rate range; Step 4.3, calculate the reagent pump flow rate according to the seawater pump flow rate obtained in Step 4.2 Calculate the reagent pump flow rate , and the specific calculation formula is as follows: wherein, k is a proportionality coefficient.

8. The control method of a high-precision pH sensor control system applicable to a mobile platform according to claim 7, characterized in that, the real-time calculation of the position during the movement of the pH sensor control system in step 7 specifically includes: Step 7.1: Calculate the time required for seawater to completely fill the detection flow path from the start based on the fixed volume detected by the seawater pump flowmeter. At the same time, the sampling time can be comprehensively obtained according to the photoelectric detection circuit and the ADC sampling circuit. Obtain the total time for the sensor to acquire data. ; Step 7.2, decompose the actual moving speed of the sensor obtained in Step 4.1 into the moving speeds along the three directions of OX, OY, and OZ , , , and obtain the moving distance of the sensor relative to the initial point . The calculation formula is as follows: ​ Among them, is the distance coordinate of the initial point O, , where i represents the i-th acquisition of position information, and n represents the n-th acquisition of position information.

Images