Lake self-sedimentation layered water sampling device and method

Abstract

The application discloses a lake self-sedimentation layered water sampling device and method, and belongs to the technical field of water quality monitoring. The device comprises a bearing table floating on the water surface, a main control box is arranged in the middle of the bearing table, a rope control lifting assembly is connected to the bottom of the main control box, the rope control lifting assembly is connected with a self-sedimentation water sampling assembly through a pull rope, the rope control lifting assembly comprises a speed regulating motor, a rope winding roller and a depth detection unit, the self-sedimentation water sampling assembly comprises a multi-cavity water sampling cylinder and a counterweight cabin, and a main control module coordinates each component to realize layered sampling. The application also discloses a lake self-sedimentation layered water sampling method. The application can accurately obtain water samples at different depths of a lake, and is suitable for lake ecological monitoring, water quality analysis and other scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water quality monitoring. More particularly, the present application relates to a lake self-sedimentation layered water sampling device and method. BACKGROUND

[0002] Lake water bodies have obvious stratification characteristics due to differences in temperature, dissolved oxygen, nutrients and other factors. For example, the water quality parameters of surface water and bottom water may differ significantly, and accurate sampling of key water layers such as the thermocline and eutrophication layer is crucial for ecological monitoring. This requires the sampling device to accurately control the sampling depth and avoid cross-contamination of samples from different water layers.

[0003] Existing layered water sampling devices have obvious limitations in adapting to the stratification characteristics of lakes: first, the depth control accuracy is insufficient. Traditional devices rely on a single parameter of rope length to determine the depth, and the sampling trigger and stop rely on manual observation. The stretching and contraction of the rope under water flow impact and the deviation of the sampling assembly under the influence of undercurrent are not considered, resulting in a deviation of the actual sampling depth from the target depth often exceeding 10%, making it difficult to capture the water quality characteristics of fine water layers such as the thermocline. Second, the sample isolation is poor. Most devices use a single-cavity sampling container, which requires sequential operation from the surface to the deep layer when stratified sampling. Upper water samples are easily left and mixed into lower samples, leading to distorted data. Third, the self-sedimentation control is extensive. The sedimentation of existing devices is mostly free sedimentation (only relying on the natural sinking of the counterweight) or pure mechanical forced lowering. The former is easily deviated from the vertical path under the disturbance of water flow, and the latter is difficult to adapt to the change of water flow resistance at different depths, resulting in poor sedimentation stability. These problems make it difficult for existing technology to meet the high-precision and low-pollution sampling needs of stratified water quality in lakes. SUMMARY

[0004] The present application provides a lake self-sedimentation layered water sampling device and method, which can accurately obtain water samples at different depths in lakes and is suitable for lake ecological monitoring, water quality analysis and other scenarios.

[0005] To achieve these objects and other advantages in accordance with the present application, a lake self-sedimentation layered water sampling device is provided, comprising:

[0006] A carrying table floats on the water surface, a main control box is fixed in the middle of the carrying table, a main control module and a power supply unit are integrated in the main control box, and an antenna for receiving instructions is provided on the top of the main control box;

[0007] A rope-controlled lifting assembly is installed at the bottom of the main control box, the rope-controlled lifting assembly includes a power unit, a rope winding and unwinding unit, and a depth detection unit, the power unit is a speed-regulating motor with a self-locking function, the rope winding and unwinding unit includes a main drive winding roller, the main drive winding roller is connected with the output shaft of the speed-regulating motor, and the depth detection unit includes a number of turns meter sleeved on the shaft end of the main drive winding roller and a ranging probe installed vertically downward;

[0008] The self-sinking water sampling assembly is connected to the rope-controlled lifting assembly through the pull rope winding and unwinding unit, and comprises a water sampling cylinder, which is internally provided with multiple partitions to divide the water sampling cylinder into multiple water sample storage cavities arranged independently from top to bottom. A counterweight cabin is arranged below the lowermost water sample storage cavity, and a replaceable counterweight is arranged in the counterweight cabin. The side wall of the water sample storage cavity is provided with a water inlet, a sealing baffle hinged to the water inlet, an elastic reset member connecting the sealing baffle and the inner wall of the water sampling cylinder, and an electrically controlled driving member fixed to the outside of the water inlet.

[0009] The main control module is electrically connected with the speed regulating motor, the tension sensor, the number of turns meter, the distance measuring probe and the electrically controlled driving member. The main control module sinks the self-sinking water sampling assembly to the deepest target depth through the rope-controlled lifting assembly. After the depth detection unit confirms the arrival, the electrically controlled driving member corresponding to the water inlet is triggered to be turned on. After sampling is completed, the self-sinking water sampling assembly is lifted to the next target depth, and the above process is repeated.

[0010] Preferably, the pull rope winding and unwinding unit further comprises a driven buffer roller arranged on one side of the driving winding roller through an elastic support. The pull rope passes between the driving winding roller and the driven buffer roller. The elastic support is provided with a tension sensor. When the tension sensor detects that the tension of the pull rope exceeds a preset threshold, the main control module controls the elastic support to be elongated, and the driven buffer roller moves away from the driving winding roller to buffer the tension.

[0011] Preferably, the water sample storage cavity is provided with a liquid level sensor electrically connected with the main control module. When the liquid level sensor detects that the water level in the cavity reaches 90% of the volume, the main control module controls the corresponding electrically controlled driving member to be reset, and simultaneously triggers the rope-controlled lifting assembly to perform a lifting action.

[0012] The method for self-sinking and layering water sampling in a lake uses the device, and the method comprises the following steps.

[0013] Step 1: The bearing table is floated in the target water area, and the main control module receives a layering sampling depth sequence instruction arranged in a top-down order.

[0014] Step 2: The speed regulating motor is started, the pull rope is released, the self-sinking water sampling assembly is sunk to the deepest target depth, the length L of the released pull rope is obtained through the number of turns meter, and the real-time water depth measurement value D is obtained through the distance measuring probe. When the absolute value of the difference between L and D is less than or equal to 0.05×D, it is confirmed that the deepest target depth is reached.

[0015] Step 3: The electrically controlled driving member of the water sample storage cavity corresponding to the current target depth is turned on to open the sealing baffle and the water inlet.

[0016] Step four, monitor the water level in the cavity by the liquid level sensor, when the water level reaches 90% of the cavity volume, close the current electric control drive to reset the sealing baffle, start the speed regulating motor to lift the water sampling cylinder;

[0017] Step five, during the lifting process, calculate the new water sample mass Δm according to the liquid level sensor data, combine the initial mass of the counterweight m0, the weight of the water sampling cylinder m1, update the total mass of the device M = m0+Δm+m1;

[0018] Step six, based on the updated M, control the speed regulating motor to run at a constant output power, so that the tension of the pull rope F satisfies:

[0019] 0.8×M×g≤F≤1.2×M×g, where g is the acceleration of gravity;

[0020] Step seven, continuously monitor the change of water depth by the ranging probe, stop lifting when the device reaches the adjacent upper target depth;

[0021] Step eight, repeat steps three to seven until all target depths are sampled;

[0022] Step nine, when the device is lifted from the nth layer to the n-1 layer, close all sealing baffles from the nth layer and below, and hover at 0.3-0.8 meters above the target depth, the hovering time ;

[0023] Step ten, continuously collect W sets of displacement data by the ranging probe, W≥10, calculate the average displacement rate, when the ranging probe detects that the displacement rate is less than or equal to 5 mm / s, sink to the target depth.

[0024] Preferably, in step six, if the tension sensor detects that the tension of the pull rope exceeds 1.5×M×g, control the elastic support to elongate, so that the driven buffer roller moves to a position 0.1-0.3 meters away from the driving rope roller, continuously monitor the tension sensor, and stop the elastic support elongation when the tension returns to the range of 0.8×M×g to 1.2×M×g.

[0025] Preferably, after obtaining Δm in step five, it further includes:

[0026] Calculate the compensation value of the rope extension amount , where E is the elastic modulus of the rope 190-210 GPa, and A is the cross-sectional area of the rope;

[0027] Correct the reading of the number of turns meter to L' = L+ΔL;

[0028] Get the current actual depth D' by the ranging probe;

[0029] If |L'-D'|>0.03xD', control the speed-regulating motor to release the rope body to make the device sink 3-5 meters, and re-lift the device until |L'-D'|≤0.03xD';

[0030] Set the corrected L' as the new depth reference value.

[0031] Preferably, after step five, calculate the imbalance degree of the counterweight ;

[0032] If ζ>0.2, control the elastic support to move the driven buffer roller to a position 0.3 meters away from the driving winding roller;

[0033] Set the initial lifting speed v0=0.3 m / s;

[0034] When the tension sensor detects F≤1.1×M×g, adjust the lifting speed to ;

[0035] If ζ≤0.2, directly set .

[0036] Preferably, during the hovering in step nine, continuously obtain W sets of displacement data through the distance measuring probe, W≥10;

[0037] Calculate the displacement standard deviation , wherein di is the displacement of the i-th set, and μ is the displacement mean value; i

[0038] If σ≤2 mm, determine that the flow field is stable, and perform the sinking operation;

[0039] If σ>2 mm, extend the hovering time to t'=1.5×t, and re-detect until σ≤2 mm;

[0040] During the sinking process, increase the sampling frequency of the distance measuring probe to 50 Hz;

[0041] When the real-time water depth value reaches 98-102% of the target depth, trigger the electric control driving member to open.

[0042] Preferably, the internal partition of the counterweight tank is provided with a magneto-rheological fluid tank, which is filled with magneto-rheological fluid, and the real-time viscosity η of which satisfies: η=η0+αI 2 , wherein η0 is the initial viscosity, and the viscosity coefficient α=0.2-0.5 Pa·s,

[0043] During the hovering in step nine, the horizontal displacement data of the device are collected in real time through the distance measuring probe, and the horizontal displacement change rate v h per unit time is calculated. h Compare v with a preset threshold value:

[0044] When v h ≥ 0.1 m / s, it is determined as a strong current environment, a first current value I1 is input to the magnetorheological fluid tank, the viscosity of the magnetorheological fluid is increased, and the weight of the device is increased to a first preset value M1;

[0045] When 0.02 m / s≤v h ≤0.1 m / s, it is determined as a medium current environment, a second current value I2 is input, the weight is maintained at a second preset value M2, I2

[0046] When v h < 0.02 m / s, it is determined as a still water environment, a third current value I3 is input, the weight is reduced to a third preset value M3, I3

[0047] During the lifting of the device, the current value is dynamically adjusted according to the real-time v h , so that the weight matches the current intensity;

[0048] Combined with the tension sensor data F, when F > 1.2 x M x g, the elastic support of the driven buffer roller is synchronously started to be elongated, and the buffer pull rope tension is elongated.

[0049] Preferably, the following data is collected and stored during each sampling process:

[0050] Environmental parameters: target depth D, water flow velocity v, turbidity T, pH value, dissolved oxygen DO;

[0051] Device parameters: pull rope tension F, lifting speed v1, hovering time t, sampling completion time t s ;

[0052] Result parameters: sampling accuracy δ, sample pollution rate ρ;

[0053] The historical data is preprocessed to construct a data set S = {(X1,Y1), (X2,Y2),..., (X n ,Y n )}, wherein X is an environmental parameter vector, and Y is a control parameter vector;

[0054] A prediction model of environmental parameters and control parameters is established by using multiple linear regression:

[0055] Y = f(X) = β0+β1X1+β2X2+...+β m X m +ε,

[0056] wherein β0-β m are coefficients, and ε is an error term,

[0057] Before a new sampling operation, input real-time environmental parameter X' into the model, and output the model-predicted control parameter Y';

[0058] During sampling, control the device using control parameter Y', and update dataset S after completion, periodically retrain the model to optimize prediction accuracy.

[0059] The present application at least includes the following benefits:

[0060] Firstly, the device of the present application provides a stable floating foundation through the bearing table, ensuring that it does not sway on the water surface. The main control module in the main control box can coordinate the work of each component, the speed regulation motor of the rope control lifting assembly and the active rope winding roller precisely control the extension and retraction of the pull rope, the depth is detected by the number of turns meter and the distance measuring probe, and the multiple independent water sample storage cavities of the self-sedimentation water sampling assembly can collect water samples at different depths respectively. The counterweight tank ensures stable sinking, and the whole realizes the basic function of stratified sampling, laying a structural foundation for subsequent accurate sampling.

[0061] Secondly, the method of the present application adopts a bottom-up sampling sequence, starting from the deepest layer to avoid pollution of upper water samples to lower layers, calibrates the depth with double parameters (pull rope length and water depth), ensures reaching the target depth, controls the sampling amount with a liquid level triggering mechanism, ensures the stability of the device during sampling with hovering and displacement detection, and standardizes the steps to reduce differences in manual operation, making the sampling process standardized and unified, effectively avoiding sample pollution and ensuring the accuracy of sampling at each depth.

[0062] Thirdly, the method of the present application adjusts the distance between the driven buffer rollers to protect the equipment when the tension exceeds the limit, compensates for the depth deviation caused by the extension and retraction of the pull rope through the extension and retraction of the rope body, stabilizes the tension by adjusting the lifting speed when the counterweight is unbalanced, and ensures that the device does not sway during sampling through flow field stability judgment, thereby improving the stability of the sampling process, reducing errors, and ensuring sample quality and equipment safety.

[0063] Fourthly, the magnetorheological fluid counterweight tank of the present application dynamically adjusts the counterweight according to the flow velocity, increases the counterweight to maintain stability in strong dark currents, reduces the counterweight to reduce energy consumption in still water areas, models historical data to learn periodic changes in water areas, outputs adaptive parameters during new sampling, and the model can be updated and optimized, reducing manual debugging and making the device adapt to different water flows and seasonal changes, improving the intelligence and adaptability of sampling.

[0064] Other advantages, objects, and features of the present application will be apparent from the following description, and will be understood by those skilled in the art through study and practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 The figure is a structural schematic diagram of one technical solution of the present application, in which 1 is a bearing table, 2 is a main control box, 3 is an antenna, and 4 is a water sampling cylinder. DETAILED DESCRIPTION

[0066] The application will be further described in detail below with reference to the drawings, so that those skilled in the art can implement the application according to the description and the drawings.

[0067] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0068] It should be noted that the experimental methods in the following embodiments are conventional methods, and the reagents and materials are commercially available unless otherwise specified. In the description of the present application, it should be noted that unless otherwise specifically defined and limited, the terms "mount", "connect", "arrange" should be understood broadly, for example, they can be fixedly connected, arranged, or detachably connected, arranged, or integrally connected, arranged. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. The orientations or positional relationships indicated by the terms "transverse", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0069] As shown in Figure 1 The present application provides a lake self-sedimentation layered water sampling device, which can solve the problems of low depth control precision, easy pollution of sampling and lack of automatic cooperative control of the existing device. The device comprises:

[0070] A bearing table 1 floats on the water surface and is a buoyant structure, which can adopt high-density foam or a hollow metal frame to ensure stable floating on the water surface. A main control box 2 is fixed in the middle of the bearing table 1 and is assembled at the center position of the bearing table 1 and fixed with the bearing table 1 by bolts. A main control module and a power supply unit are integrated in the main control box 2. The main control module can adopt a single-chip microcomputer, and the power supply unit can adopt a lithium battery. An antenna 3 for receiving instructions is arranged at the top of the main control box 2 and connected with the main control module through an interface.

[0071] The rope control lifting assembly is installed at the bottom of the main control box 2, and comprises a power unit, a rope winding and unwinding unit and a depth detection unit. The power unit is a speed regulating motor with self-locking function, which can accurately control the winding and unwinding of the rope. The rope winding and unwinding unit comprises a driving winding roller, which is connected with the output shaft of the speed regulating motor through a shaft coupling and is assembled at the middle position of the bottom of the main control box 2. The depth detection unit comprises a number of turns meter arranged on the shaft end of the driving winding roller and a vertical downward distance measuring probe. The number of turns meter can adopt a rotary encoder, and the distance measuring probe can adopt an ultrasonic distance measuring module and is assembled at the edge of the bottom of the main control box 2. One end of the rope is fixed on the driving winding roller, and the other end is connected with the self-sedimentation water sampling assembly.

[0072] The self-sedimentation water sampling assembly is connected with the rope control lifting assembly through the rope winding and unwinding unit. The self-sedimentation water sampling assembly comprises a water sampling cylinder 4 which is a substantially cylindrical tubular structure. The inside of the water sampling cylinder 4 is provided with a plurality of partitions, which divide the water sampling cylinder 4 into a plurality of water sample storage cavities arranged independently from top to bottom. A counterweight chamber is arranged below the lowermost water sample storage cavity, i.e. at the lowermost end of the water sampling cylinder 4. The counterweight chamber is provided with replaceable counterweight members, such as lead blocks (weight 5-10 kg, adjusted according to water depth). The side wall of the water sample storage cavity is provided with a water inlet, a sealing baffle hinged to the water inlet, an elastic reset member connecting the sealing baffle and the inner wall of the water sampling cylinder 4, and an electrically controlled driving member fixed to the outside of the water inlet. The sealing baffle is matched with the water inlet. The elastic reset member can adopt a spring, and the electrically controlled driving member can adopt an electromagnetic push rod corresponding to the sealing baffle.

[0073] The main control module is electrically connected with the speed regulating motor, the tension sensor, the number of turns meter, the distance measuring probe and the electrically controlled driving member. The main control module sinks the self-sedimentation water sampling assembly to the deepest target depth through the rope control lifting assembly. When the depth detection unit confirms the arrival, the electrically controlled driving member corresponding to the water inlet is triggered to open. After sampling is completed, the self-sedimentation water sampling assembly is lifted to the next target depth, and the above process is repeated.

[0074] During operation, the main control module controls the speed regulating motor to release the rope, and the self-sedimentation water sampling assembly is sunk. After the depth is confirmed by the number of turns meter and the distance measuring probe, the electrically controlled driving member pushes open the sealing baffle to take water. After completion, the sealing baffle is reset and the self-sedimentation water sampling assembly is lifted. The above operation is repeated to realize stratified sampling. The device can stably float on the water surface, accurately control sampling at different depths, and is suitable for the collection of stratified water samples in lakes.

[0075] In the above technical solution, the bearing table 1 provides a stable floating foundation, the rope control lifting assembly improves the depth control accuracy by combining double depth detection (rope length + distance measuring probe), realizes accurate and independent collection of water samples at different depths, the multiple independent chambers of the self-sedimentation water sampling assembly avoid sample contamination, and the components are coordinated by the main control module to realize automatic stratified sampling, thereby improving the operation efficiency and sampling reliability.

[0076] The tension of the pull rope is prone to sudden change due to water flow impact and equipment shaking during lifting, which may cause the pull rope to break or the stability of the sampling assembly to decrease. In another technical solution, the pull rope winding and unwinding unit further comprises a driven buffer roller, which is arranged on one side of the driving winding roller through an elastic support, the elastic support is fixed on the rack of the bearing table 1 through bolts, is parallel to the axis of the driving winding roller, and after the pull rope is led out from the driving winding roller, the pull rope can naturally pass through the gap between the driving winding roller and the driven buffer roller. A tension sensor is arranged on the elastic support, and a spring fixed on the elastic support is connected with the support base. When the tension sensor detects that the tension of the pull rope exceeds a preset threshold, for example, 80% of the safe bearing capacity of the pull rope, a signal is sent to the master control module, the master control module controls the driving part of the elastic support to act through a relay, the master control module controls the elastic support to elongate, and the driven buffer roller moves away from the driving winding roller to increase the distance between the two, so as to buffer the tension. The driven buffer roller cooperates with the elastic support to buffer the tension by adjusting the distance when the tension exceeds the threshold, the tension sensor monitors and triggers the adjustment in real time, reduces the risk of pull rope wear and breakage, reduces the impact of tension fluctuation on the sampling assembly, ensures the stability during lifting, and adapts to complex water environment.

[0077] The amount of water sample collected cannot be accurately judged during sampling, which is prone to overfilling or insufficient collection, affecting the effectiveness of the sample and the coherence of subsequent operations. In another technical solution, the water sample storage cavity is provided with a liquid level sensor, and the detection range covers the bottom to the top of the water sample storage cavity. The liquid level sensor is electrically connected with the master control module, and the water level in the water sample storage cavity is monitored in real time. When the liquid level sensor detects that the water level in the cavity reaches 90% of the volume, the master control module controls the corresponding electrically controlled driving part to reset, drives the sealing baffle to close the water inlet, and simultaneously triggers the rope-controlled lifting assembly to perform a lifting action, so as to avoid sample overflow and pollution, ensure sufficient collection, and ensure sampling efficiency and sample integrity.

[0078] Due to the lack of standardized procedures for stratified sampling, the disorder of depth sequence may easily lead to sample pollution, and the operation of depth calibration, sampling triggering and other links is arbitrary, which affects the sampling accuracy and consistency. The present application provides a method for stratified sampling of lake self-settling water, which applies the device, and the method comprises:

[0079] Step one, float the bearing table 1 in the target water area through the anchor rope to fix the position, avoid large drift with the water flow, and the master control module receives the stratified sampling depth sequence instruction, which is arranged in the order from bottom to top, the interval between adjacent depths is 1-2 meters, and the deepest target depth can be set according to the actual water depth of the lake, such as 5-30 meters;

[0080] Step two, start the speed regulating motor, release the pull rope to make the self-sinking water sampling assembly sink to the deepest target depth, obtain the pull rope release length L through the number of turns meter, obtain the real-time water depth measurement value D through the distance measuring probe, and the data is transmitted to the main control module in real time, when the absolute value of the difference between L and D is ≤0.05xD, the main control module confirms that the deepest target depth is reached;

[0081] Step three, the main control module only triggers the water sample storage cavity corresponding to the current target depth to act, that is, the electric control driving part of the water sample storage cavity corresponding to the current target depth is started to make the sealing baffle open the water inlet;

[0082] Step four, the main control module monitors the water level in the cavity through the liquid level sensor, and the liquid level sensor calculates the new water sample volume and mass through the water level height, and when the water level reaches 90% of the cavity volume, the current electric control driving part is closed to reset the sealing baffle, and the speed regulating motor is started to lift the water sampling cylinder 4;

[0083] Step five, during the lifting process, the main control module calculates the new water sample mass Δm according to the liquid level sensor data, combines the initial mass m0 of the counterweight, the weight m1 of the water sampling cylinder 4, and updates the total mass M of the device = m0+Δm+m1;

[0084] Step six, based on the updated M, the speed regulating motor is controlled to run at a constant output power, and the pull rope tension F is adjusted to meet:

[0085] 0.8×M×g≤F≤1.2×M×g, wherein g is the acceleration of gravity 9.8 m / s 2 ;

[0086] Step seven, continuously monitor the water depth change through the distance measuring probe, and stop lifting when the device reaches the adjacent upper target depth;

[0087] Step eight, repeat steps three to seven until all target depth sampling is completed;

[0088] Step nine, when the device is lifted from the nth layer to the n-1 layer, the main control module outputs an instruction to close the n-layer sealing baffle through the relay, and detects the state of all sealing baffles below the n-layer to ensure complete closure, ensure that the lower water sample does not leak, and hover at 0.3-0.8 meters above the target depth, the current depth flow rate can be obtained through the flow rate sensor assembled on the outside of the water sampling cylinder 4, and the hovering time ;

[0089] Step ten, continuously collect W sets of displacement data through the distance measuring probe, W≥10, calculate the average displacement rate, and when the distance measuring probe detects that the displacement rate is ≤5 mm / s, sink to the target depth.

[0090] In the above technical solution, the bearing table 1 receives the depth sequence after being fixed, first sinks the self-sinking water sampling assembly to the deepest target depth, lifts after the water level is full, synchronously updates the total mass and controls the tension; lifts to hover above the upper target depth, sinks for sampling after the displacement is stable, and repeats the operation until completion. The depth sequence from bottom to top avoids pollution from the upper layer to the lower layer, the double parameters (rope length + water depth) calibrate the depth, the liquid level triggers the closing and lifting, forms a standardized process, ensures the independence and accuracy of samples at each depth, and improves the standardization and reliability of layered sampling.

[0091] When the tension of the pull rope suddenly exceeds the limit (such as a dark current impact), there is a lack of effective buffer mechanism, which may cause damage to the equipment or interruption of sampling. In another technical solution, in step six, when the pull rope is lifted, the tension sensor continuously monitors the tension and transmits data to the main control module. If factors such as dark current impact cause the tension sensor to detect that the tension of the pull rope exceeds 1.5×M×g, the driven buffer roller spacing adjustment is triggered, the tension is reduced to a safe range through physical buffering, and then the elastic support is controlled by a miniature electric push rod to extend, so that the driven buffer roller moves to a position 0.1-0.3 meters away from the driving winding roller. The tension sensor is continuously monitored, the tension gradually decreases, and when the tension returns to the range of 0.8×M×g to 1.2×M×g, the extension of the elastic support is stopped. The rapid buffer tension mutation avoids overloading and damage to the pull rope, avoids interruption of sampling due to excessive tension of the equipment, and ensures the safety of the equipment and the continuity of sampling.

[0092] The stretching and contraction of the rope body due to tension can easily cause deviation in depth measurement, affecting the accuracy of sampling depth. In another technical solution, after obtaining Δm in step five, it further includes:

[0093] Calculate the compensation value of the stretching and contraction of the rope body , where E is the elastic modulus of the rope body 190-210 GPa, and A is the cross-sectional area of the rope body;

[0094] Correct the reading of the number of turns meter to L’ = L+ΔL;

[0095] Obtain the current actual depth D’ through the ranging probe;

[0096] If |L’-D’|>0.03×D’, control the speed regulating motor to release the rope body to make the device sink 3-5 meters, and lift the device again until |L’-D’|≤0.03×D’;

[0097] Set the corrected L’ as the new depth reference value.

[0098] After obtaining Δm, the host module automatically calls real-time parameters (F, M, L, E, A) to calculate ΔL, combines with the actual water depth calibration, corrects the measurement deviation through the rope body expansion and contraction compensation, corrects L of the number of turns meter to L', and simultaneously measures the actual water depth D' by the ranging probe. The host module compares the difference between |L'-D'| and 0.03xD', controls the device to sink and lift, continuously corrects L' and monitors the difference, reduces the depth error caused by the tension of the rope body, and stops until the standard is reached.

[0099] In the above technical solution, the length of the pull rope is corrected by the rope body expansion and contraction compensation formula, and the actual water depth calibration is combined with the ranging probe to ensure that the depth measurement deviation is less than or equal to 0.03xD', which improves the depth control accuracy and adapts to the measurement error caused by the physical characteristics of the rope body.

[0100] When the added water sample causes the imbalance of the counterweight, the lifting speed is fixed, which can easily cause tension fluctuation, affecting the stability of the device and the sampling efficiency. In another technical solution, after step five, the water level height is obtained by the liquid level sensor of the water sample storage cavity, the added water sample volume is calculated by combining the cross-sectional area of the cavity, and the counterweight imbalance degree ζ is calculated ;

[0101] When the imbalance occurs, the device stability is enhanced by structural adjustment. If ζ>0.2, the host module controls the elastic support to elongate, and the elastic support moves the driven buffer roller to a position 0.3 meters away from the driving winding roller.

[0102] The initial lifting speed v0 is set to 0.3 m / s.

[0103] When the tension sensor detects that F≤1.1×M×g, the lifting speed is adjusted to ;

[0104] If ζ≤0.2, the driven buffer roller remains in the initial position (no adjustment is needed), and is directly set.

[0105] In the above technical solution, when the device is caused by the added water sample, the imbalance state is judged by the counterweight imbalance degree, the initial lifting speed and the acceleration condition are adjusted accordingly, the tension stability and the lifting efficiency are balanced, and the device shaking or tension overrun caused by the imbalance is avoided.

[0106] When the flow field is unstable, sinking sampling can easily cause depth deviation due to shaking, affecting the sampling accuracy. In another technical solution, during hovering in step nine, W sets of displacement data are continuously obtained by the ranging probe, W≥10, and the influence of accidental fluctuation is reduced by multiple measurements.

[0107] The displacement standard deviation σ is calculated , and the smaller σ is, the smoother the displacement fluctuation is, where d is the displacement data and μ is the displacement mean.

[0108] If σ≤2 mm, it is determined that the displacement fluctuation is small during hovering and the flow field is stable, and the sinking operation is performed;

[0109] If σ>2 mm, it is determined that the device is still disturbed by the water flow. Wait for the water flow disturbance to weaken naturally, give the device enough time to adapt to the flow field changes, extend the hovering time to t' = 1.5×t, and retest until σ≤2 mm;

[0110] During the sinking process, the device is in motion and the flow field may be locally disturbed. Increasing the sampling frequency of the ranging probe to 50 Hz can track subtle changes in depth in real time, allowing the main control module to accurately grasp the device's position.

[0111] When the real-time water depth value reaches 98-102% of the target depth, the electronically controlled drive is triggered to open.

[0112] In the above technical solution, the flow field stability is judged by the displacement standard deviation. When it is unstable, the hovering is extended and re-tested. When sinking, the sampling frequency is increased to ensure that sampling is carried out in a stable flow field state and reduce the impact of water flow disturbance on depth accuracy.

[0113] It is difficult to achieve a balanced balance between stability and energy consumption when fixing the counterweight in an undercurrent environment. It is prone to shaking in strong undercurrents and consumes too much energy in static water areas. In another technical solution, a magnetorheological fluid tank is separated from the counterweight cabin, with a volume of 0.5-1 L, and is filled with magnetorheological fluid. The viscosity of the magnetorheological fluid can be adjusted steplessly by current. The current regulating device can use a DC current controller (output current 0-5A), which is installed in the main control box 2 and connected to the electromagnetic coil of the magnetorheological fluid tank through a wire. The real-time viscosity η changes with the current input current I. The real-time viscosity η and the input current I satisfy: η = η0+αI 2 , where η0 initial viscosity, η0 = 0.1-0.3 Pa·s, viscosity coefficient α = 0.2-0.5 Pa·s,

[0114] During the hovering period in step nine, the horizontal displacement data of the device is collected in real time by the ranging probe, and the horizontal displacement data is continuously collected. h The horizontal displacement change rate v per unit time is calculated by calculating the difference between two adjacent groups of displacements / time intervals. h , v h Compared with the preset threshold, set the three-level threshold: v h >0.1 m / s (strong undercurrent), 0.02m / s≤v h ≤0.1m / s (medium flow rate), v h <0.02m / s (still water environment):

[0115] When v hWhen the velocity is greater than 0.1 m / s, it is determined to be a strong undercurrent environment. In the case of strong undercurrent, high viscosity (high counterweight) is used to resist the impact. A first current value I1 is input into the magnetorheological fluid tank to increase the viscosity of the magnetorheological fluid. The counterweight of the device is increased to the first preset value M1 to avoid shaking.

[0116] When 0.02 m / s≤v h When the flow rate is ≤0.1 m / s, it is determined to be a medium flow environment, and the second current value I2 is input to maintain the counterweight at the second preset value M2, balancing stability and energy consumption, I2<I1, M2<M1;

[0117] When v h When the speed is less than 0.02 m / s, it is determined to be a still water environment. In the still water area, low viscosity (low counterweight) is used to reduce the lifting load. The third current value I3 is input to reduce the counterweight to the third preset value M3 to reduce energy consumption during lifting. I3<I2, M3<M2;

[0118] During the lifting process of the device, according to the real-time v h Dynamically adjust the current value to match the counterweight with the dark current intensity;

[0119] Combined with the tension sensor data F, when F>1.2×M×g, the elastic bracket of the driven buffer roller is synchronously started to extend to buffer the tension of the pull rope.

[0120] In the above technical solution, the water flow during the lifting process may be more complicated (such as the existence of vertical undercurrent). The intensity of the undercurrent is judged by the rate of change of horizontal displacement. Dynamic adjustment of the current can ensure that the counterweight always adapts to the real-time water flow. When the undercurrent is strong, the counterweight is increased to ensure stability. When the water area is still, the counterweight is reduced to reduce energy consumption. The tension buffering and counterweight adjustment are coordinated to reduce the source of shaking through the counterweight and buffer the residual tension through the bracket to adapt to the complex water flow environment.

[0121] Lakes require regular sampling, and water environment parameters (such as water flow velocity and water temperature stratification depth in different seasons) change periodically. Fixed control parameters have poor adaptability and require repeated manual debugging, making intelligent sampling difficult. In another technical solution, the following data is collected and stored during each sampling process:

[0122] Environmental parameters: target depth D, water velocity v, turbidity T, pH value, dissolved oxygen DO, directly reflect the real-time status of lake waters and are periodic;

[0123] Equipment parameters: rope tension F, lifting speed v1, hovering time t, sampling completion time t s , the control parameters of the actual operation of the equipment;

[0124] Result parameters: sampling accuracy δ, sample contamination rate ρ, , , V 总The total volume of the sample collected by the sampler, after sampling, the water quality parameters (such as actual water temperature, actual turbidity) of the sample are detected by the micro sensor (such as water temperature sensor, turbidity sensor) built in the sample container, if the deviation exceeds the threshold value, it is determined that the part of the sample is contaminated water, and the volume V of the contaminated water is measured by the sample volume sensor 污 , verify the validity of the control parameters, if the corresponding δ of a group of parameters is small and the corresponding ρ is low, it means that the parameters adapt to the corresponding environment, and can be used as high-quality samples for model training;

[0125] The historical data is preprocessed to construct a data set S = {(X1,Y1), (X2,Y2),..., (X n ,Y n )}, wherein X is an environmental parameter vector, X1, X2,..., X n represent target depth D, water flow velocity v, turbidity T, pH value, dissolved oxygen DO, etc., Y is a control parameter vector, Y1, Y2,..., Y n represent the tension of the pull rope F, the lifting speed v1, the hovering time t, etc.

[0126] Multiple linear regression can quantify the influence of multiple environmental parameters on control parameters, environmental parameters X as input, reflecting the objective conditions at the time of sampling, control parameters Y as output, are operating quantities adjusted according to environmental conditions, the purpose is to achieve high sampling accuracy and low sample pollution rate in different environments, thereby establishing the correlation model between the two, and using multiple linear regression to establish a prediction model of environmental parameters and control parameters:

[0127] Y = f(X) = β0+β1X1+β2X2+...+β m X m +ε,

[0128] Where β0-β m are coefficients, and ε is an error term,

[0129] The coefficients β0-β m are iteratively optimized through historical data, and before new sampling work, real-time environmental parameters X' are input into the model, and the control parameters Y' predicted by the model are output.

[0130] When performing sampling, the control parameters Y' are used to control the device, and the data set S is updated after completion, and the model is periodically retrained to optimize the prediction accuracy.

[0131] In the technical scheme, the environment and control parameter model is constructed through historical data, periodic change rules of the water area can be learned, optimized parameters are output based on real-time environment parameters when new sampling is performed, and the model is dynamically updated, adaptive control of the same water area and adaptive scene application of different water areas are realized, manual intervention is reduced, and intelligent level is improved.

[0132] The number of devices and the scale of processing described herein are intended to be illustrative of the application. Applications, modifications and variations of the application will be apparent to those skilled in the art without departing from the general concept of the application.

[0133] Although embodiments of the application have been disclosed in connection with the specified embodiments, it should be understood that they can be applied in various fields of endeavor, and that there exist additional modifications which are apparent to those skilled in the art. Therefore, to the extent that the application is not limited by the specific disclosed embodiments, the application is not intended to be limited by specific illustrated embodiments and examples and including all modifications and alternatives falling within the scope of the claims and equivalents thereof.

Claims

1. Lake self-sedimentation stratification water sampling device, characterized in that: include: A carrier platform floats on the water surface. A main control box is fixed in the middle of the carrier platform. The main control box integrates a main control module and a power supply unit. An antenna for receiving commands is provided on the top of the main control box. A rope-controlled lifting assembly is installed at the bottom of the main control box. The rope-controlled lifting assembly includes a power unit, a rope retracting unit, and a depth detection unit. The power unit is a speed-regulating motor with a self-locking function. The rope retracting unit includes an active rope roller connected to the output shaft of the speed-regulating motor. The depth detection unit includes a turns meter sleeved on the end of the active rope roller shaft and a distance measuring probe installed vertically downward. The self-sinking water sampling component is connected to the rope-controlled lifting component through the pull rope retracting and releasing unit. The self-sinking water sampling component includes a water sampling barrel. A plurality of partitions are provided inside the water sampling barrel to separate the water sampling barrel into a plurality of water sample storage chambers independently arranged from top to bottom. A counterweight cabin is provided below the water sample storage chamber on the bottom layer. A replaceable counterweight is provided in the counterweight cabin. A water inlet, a sealing baffle hinged to the water inlet, an elastic reset member connecting the sealing baffle and the inner wall of the water sampling barrel, and an electric control drive member fixed to the outside of the water inlet are provided on the side wall of the water sample storage chamber. The main control module is electrically connected to the speed regulating motor, tension sensor, circle meter, distance measuring probe and electric control drive respectively. The main control module sinks the self-settling water sampling assembly to the deepest target depth through the rope-controlled lifting assembly. After the depth detection unit confirms that it has reached the target depth, it triggers the electric control drive of the corresponding water intake to open. After the sampling is completed, it is lifted to the next target depth and the above process is repeated.

2. The lake self-sedimentation stratification water sampling device according to claim 1, characterized in that: The rope retracting and releasing unit also includes a driven buffer roller, which is arranged on one side of the active rope winding roller through an elastic bracket. The rope passes between the active rope winding roller and the driven buffer roller. A tension sensor is provided on the elastic bracket. When the tension sensor detects that the rope tension exceeds a preset threshold, the main control module controls the elastic bracket to extend, and the driven buffer roller moves away from the active rope winding roller to buffer the tension.

3. The lake self-sedimentation stratification water sampling device according to claim 1, characterized in that: The water sample storage chamber is provided with a liquid level sensor, which is electrically connected to the main control module. When the liquid level sensor detects that the water level in the chamber reaches 90% of the volume, the main control module controls the corresponding electronically controlled drive component to reset and synchronously triggers the rope-controlled lifting assembly to perform the lifting action.

4. A method for collecting water samples from lakes by self-sedimentation stratification, using the device according to any one of claims 1 to 3, characterized in that: The method comprises: Step 1: The carrier platform floats in the target waters, and the main control module receives the layered sampling depth sequence instruction, which is arranged in order from bottom to top; Step 2: Start the speed regulating motor and release the rope to make the self-sinking water sampling assembly sink to the deepest target depth. The rope release length L is obtained by the turn meter, and the real-time water depth measurement value D is obtained by the ranging probe. When the absolute value of the difference between L and D is ≤0.05×D, it is confirmed that the deepest target depth has been reached. Step 3: Turn on the electric control drive of the water sample storage chamber corresponding to the current target depth, so that the sealing baffle opens the water inlet; Step 4: Monitor the water level in the cavity through the liquid level sensor. When the water level reaches 90% of the cavity volume, turn off the current electronic control drive to reset the sealing baffle, and start the speed regulating motor to lift the water sampling tube; Step 5: During the lifting process, calculate the added water sample mass Δm based on the liquid level sensor data, combine it with the initial mass m0 of the counterweight, take the weight of the water sample tube m1, and update the total mass of the device M = m0+Δm+m1; Step 6: Based on the updated M, control the speed regulating motor to run at a constant output power so that the rope tension F satisfies: 0.8×M×g≤F≤1.2×M×g, where g is the acceleration due to gravity; Step 7: Continuously monitor the water depth changes through the ranging probe, and stop lifting when the device reaches the adjacent upper target depth; Step 8: Repeat steps 3 to 7 until all target depths are sampled. Step 9: When the device is lifted from the nth floor to the n-1th floor, close all the sealing baffles on and below the nth floor and hover at 0.3-0.8 meters above the target depth. The hovering time is ; Step 10: Continuously collect W groups of displacement data through the ranging probe, where W is greater than or equal to 10, and calculate the average displacement change rate. When the ranging probe detects a displacement change rate of less than or equal to 5 mm / s, sink to the target depth.

5. The lake self-sedimentation stratification water sampling method according to claim 4, characterized in that: In step six, if the tension sensor detects that the rope tension exceeds 1.5×M×g, the elastic bracket is controlled to extend, so that the driven buffer roller moves to a position 0.1-0.3 meters away from the active rope roller, and the tension sensor is continuously monitored until the tension returns to the range of 0.8×M×g to 1.2×M×g, and the elastic bracket is stopped from extending.

6. The lake self-sedimentation stratification water sampling method according to claim 4, characterized in that: After obtaining Δm in step 5, the following steps are also included: Calculate the rope expansion compensation value , where E is the elastic modulus of the rope, 190-210 GPa, and A is the cross-sectional area of ​​the rope; Correct the turns meter reading to L' = L + ΔL; Get the current actual depth D' through the ranging probe; If |L'-D'|>0.03×D', control the speed regulating motor to release the rope to make the device sink 3-5 meters, and then lift the device again until |L'-D'|≤0.03×D'; Set the corrected L' as the new depth reference value.

7. The lake self-sedimentation stratification water sampling method according to claim 4, characterized in that: After step 5, calculate the weight imbalance ; If ζ>0.2, control the elastic bracket to move the driven buffer roller to a position 0.3 meters away from the active rope roller; Set the initial lifting speed v0 = 0.3 m / s; When the tension sensor detects F≤1.1×M×g, adjust the lifting speed to ; If ζ≤0.2, directly set .

8. The lake self-sedimentation stratification water sampling method according to claim 4, characterized in that: During the hovering period in step nine, W groups of displacement data are continuously acquired through the ranging probe, where W ≥ 10; Calculate the displacement standard deviation , where d i is the displacement of group i, μ is the mean displacement; If σ≤2 mm, the flow field is determined to be stable and the sinking operation is performed; If σ>2 mm, extend the hovering time to t' = 1.5×t and retest until σ≤2 mm; During the sinking process, the sampling frequency of the ranging probe was increased to 50 Hz; When the real-time water depth value reaches 98-102% of the target depth, the electronically controlled drive is triggered to open.

9. The lake self-sedimentation stratification water sampling method according to claim 4, characterized in that: The counterweight cabin is separated by a magnetorheological fluid cabin filled with magnetorheological fluid, and its real-time viscosity η and input current I satisfy: η = η0+αI 2 , where η0 is the initial viscosity, and the viscosity coefficient α = 0.2-0.5 Pa·s, During the hovering period in step nine, the horizontal displacement data of the device is collected in real time by the ranging probe, and the horizontal displacement change rate per unit time v is calculated. h , v h Comparison with preset thresholds: When v h When the speed is greater than 0.1 m / s, it is determined to be a strong dark current environment, and a first current value I1 is input into the magnetorheological fluid chamber to increase the viscosity of the magnetorheological fluid and increase the device weight to a first preset value M1; When 0.02 m / s≤v h When the flow rate is less than or equal to 0.1 m / s, it is determined to be a medium flow rate environment, and a second current value I2 is input to maintain the counterweight at a second preset value M2, where I2 is less than I1 and M2 is less than M1. When v h When the speed is less than 0.02 m / s, it is determined to be a still water environment, and a third current value I3 is input to reduce the counterweight to a third preset value M3, where I3 is less than I2 and M3 is less than M2; During the lifting process of the device, according to the real-time v h Dynamically adjust the current value to match the counterweight with the dark current intensity; Combined with the tension sensor data F, when F>1.2×M×g, the elastic bracket of the driven buffer roller is synchronously started to extend to buffer the tension of the pull rope.

10. The lake self-sedimentation stratification water sampling method according to claim 4, characterized in that: During each sampling process, the following data is collected and stored: Environmental parameters: target depth D, water velocity v, turbidity T, pH value, dissolved oxygen DO; Equipment parameters: rope tension F, lifting speed v1, hovering time t, sampling completion time t s ; Result parameters: sampling accuracy δ, sample contamination rate ρ; Preprocess the historical data and construct the data set S = {(X1,Y1), (X2,Y2), ..., (X n ,Y n )}, where X is the environmental parameter vector and Y is the control parameter vector; Multiple linear regression was used to establish a prediction model for environmental parameters and control parameters: Y = f(X) = β0+β1X1+β2X2+...+β m X m +e, Among them, β0-β m is the coefficient, ε is the error term, Before a new sampling operation, the real-time environmental parameter X' is input into the model, and the control parameter Y' predicted by the model is output; When sampling is performed, the control parameter Y' is used to control the device, and after completion, the dataset S is updated and the model is retrained periodically to optimize the prediction accuracy.

Images