Shipborne water depth measuring device and method based on Archimedes law

Abstract

The invention provides a shipborne water depth measuring device based on the Archimedes law. The shipborne water depth measuring device comprises a tension sensor, a U-groove fixed pulley, a servo motor, a roller meter counter, a rope, a spherical metal weight and a shipborne platform. The tension sensor, the U-groove fixed pulley, the servo motor and the roller meter counter are sequentially and fixedly arranged on the shipborne platform and are connected through a rope; the spherical metal weight is connected with the tail end of the rope and pulls the rope to sink into a water body to be detected. The invention also provides a method for realizing water depth measurement by using the device, which comprises the following steps of: firstly calibrating critical tension in two buoyancy balance states and the length of a fixed rope outside the water surface in a calibration environment according to the Archimedes principle, and realizing accurate water depth measurement in an actual measurement environment according to the critical tension and the length of the fixed rope outside the water surface. The equipment is simple in structure, intuitive in algorithm principle and convenient to operate, can reduce the influence of factors such as river bottom sludge, aquatic plants and fish schools on the measurement precision, and can also be effectively applied to precise water depth measurement tasks of water areas such as rivers, lakes and shallow seas.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrographic surveying and mapping, and is applicable to high-precision water depth measurement in areas such as rivers, lakes, and shallow seas. In particular, it relates to a shipborne water depth measurement device and method based on Archimedes' law. Background Technique

[0002] Water depth measurement is an important link in hydrographic survey and engineering construction. In the fields of earth science and related engineering, water depth, as a key parameter reflecting the structure and dynamic changes of water bodies, not only affects the energy transmission, sediment evolution, and ecosystem distribution in the ocean and rivers, but also is an important basis for evaluating flood risks, guiding waterway design, and water conservancy project construction.

[0003] Currently, water depth measurement usually adopts non-contact measurement methods such as sonar, laser, or radio. For example, a water depth measurement method and device for a narrow and deep river section in canyon are disclosed in CN201611021688.7; a water depth measurement device and measurement method for reservoir construction are disclosed in CN117387720B; and a method for judging the uniformity distribution of shipborne water depth measurement data proposed by some researchers such as Fan Diao, Li Shanshan, Zhao Dongming, etc.

[0004] However, these measurement methods mainly perform non-contact measurement on the river bottom through radio and laser. The measurement process is easily affected by the interference of fish schools and waterweed reflections, as well as the thickness of river bottom silt (silt is not included in the river bottom), making it difficult to achieve accurate water depth measurement. Summary of the Invention

[0005] Technical Solution: The present invention aims to solve the problem that non-contact water depth measurement devices and methods such as radio, laser, and sonar are easily affected by factors such as fish schools, waterweeds, and river bottom silt reflections (silt thickness is not included in the river bottom) to achieve simple and precise water depth measurement. A shipborne water depth measurement device based on Archimedes' law is provided. The specific technical solution is as follows:

[0006] It includes a tension sensor, a U-groove fixed pulley, a servo motor, a roller counter, a rope, a spherical metal weight, a shipborne platform, and a data cable; the tension sensor, the U-groove fixed pulley, the servo motor, and the roller counter are sequentially fixedly installed on the shipborne platform and are connected by the rope; the spherical metal weight is connected to the end of the rope and pulls the rope to sink into the water body to be measured; among them, the tension sensor, the servo motor, and the roller counter are electrically connected through the data cable.

[0007] As an improvement, after calibrating the tension values of the tension sensor under different critical buoyancy states, it is used to judge the buoyancy state of the spherical metal weight in the actual measurement environment.

[0008] As an improvement, after calibrating the fixed rope length outside the water surface of the roller counter, it is used to calculate the actual water depth in the actual measurement environment.

[0009] As an improvement, the servo motor is used to provide power for the rope retracting and releasing.

[0010] In the present invention, another specific implementation manner is also provided. A shipborne water depth measurement method based on Archimedes' law is proposed. The method includes a calibration process and an actual measurement process. The calibration process is to calibrate the critical tensile force values F min and F max in two buoyancy balance states, and the fixed rope length L0 from the roller counter to the water surface. The actual measurement process is to use the calibrated critical tensile force values, the fixed rope length from the roller counter to the water surface, and the total rope length L i measured on site to obtain the calculated value of the water depth h i .

[0011] The method includes a calibration process and an actual measurement process; the calibration process is to calibrate the critical tensile force values F min and F max in two buoyancy balance states, and the fixed rope length L0 outside the water surface; the actual measurement process is to use the calibrated critical tensile force values and the fixed rope length outside the water surface, and the total rope length L i measured on site to obtain the calculated value of the water depth h i .

[0012] As an improvement, the specific steps of the calibration process are as follows:

[0013] Step 1: Construction of the calibration environment

[0014] After filling the water tank or bucket with water to construct the calibration environment, install any of the above shipborne water depth measurement devices based on Archimedes' law on the shipborne platform, and then place the shipborne platform on the water surface of the calibration environment. Pull the rope with a spherical metal weight until it touches the bottom of the calibration environment;

[0015] Step 2: Realization of the calibration process

[0016] Under the calibration environment, retract the spherical metal weight through the servo motor, and at the same time observe the state of the rope until it is straightened and recorded as buoyancy balance state I, and record the tensile force value at this time as F min ; Subsequently, gradually increase the tensile force until the spherical metal weight just breaks away from the bottom of the water and is recorded as buoyancy balance state II, record the tensile force value at this time as F max and the total rope length L II recorded by the roller counter, and measure the actual water depth value h0 at this time.

[0017] As an improvement, by subtracting the actual water depth from the recorded total rope length, the fixed rope length outside the water surface can be calibrated: L0 = L II - h0 + 2R, where R represents the radius of the spherical metal weight. At this time, the calibration of the tensile force values and the fixed rope length outside the water surface under two critical states is completed.

[0018] As an improvement, the specific steps of the actual measurement process are as follows:

[0019] Step 3: The operation process of actual measurement

[0020] During the actual measurement process in water areas, such as in environments like rivers, lakes, and shallow seas, when the spherical metal weight touches the bottom at the measurement point, recover the spherical metal weight with a tensile force less than F min , until the rope length no longer changes, that is, the situation of buoyancy balance state I is reached; then gradually increase the tensile force until F max is reached, that is, the situation of buoyancy balance state II is reached. Record the rope length L i at this time through the roller counter;

[0021] Step 4: The calculation process of actual measurement

[0022] Calculate the actual water depth at this measurement point by subtracting the calibrated fixed rope length outside the water surface from the recorded rope length: h i = L i - L0 + 2R, where L i is the rope length of the actual measurement in Step 3, the subscript i represents the i-th measurement point, and L0 is the fixed rope length outside the water surface calibrated in Step 2.

[0023] Beneficial effects: The method proposed by the present invention introduces a tensile force sensor and a roller counter into the measurement system, and uses Archimedes' principle to calibrate the critical tensile force values and the fixed rope length outside the water surface under two buoyancy balance states in a calibration environment, and accordingly realizes accurate water depth measurement in an actual measurement environment.

[0024] The device designed by the present invention has the advantages of simple equipment structure and convenient operation method, and the proposed calculation method has the characteristics of intuitive algorithm principle and easy implementation. Compared with conventional methods, the present invention is different from non-contact water depth measurement methods such as radio and laser. The present invention can avoid the influence of factors such as river bottom silt, water plants, and fish schools on the measurement accuracy, and can be effectively applied to precision water depth measurement tasks in waters such as rivers, lakes, and shallow seas. Description of the drawings

[0025] Figure 1 is the overall framework diagram of the present invention.

[0026] Figure 2These are the three states of Embodiment 1 of the present invention (the rope is not recovered, the rope is taut, and the spherical metal weight is about to leave the bottom of the water).

[0027] Figure 3 This is the hanging state of Embodiment 2 of the present invention.

[0028] Figure 4 This is the suspended state of the spherical metal weight in Embodiment 2 of the present invention.

[0029] Figure 5 This is the state where the spherical metal weight in Embodiment 2 of the present invention touches the bottom but is not recovered.

[0030] Figure 6 This is the state where the spherical metal weight in Embodiment 2 of the present invention is recovered until the rope is taut.

[0031] Figure 7 This is the state where the spherical metal weight in Embodiment 2 of the present invention is recovered until it just leaves the bottom of the water.

[0032] In the figure: 1 - tension sensor, 2 - U-groove fixed pulley, 3 - servo motor, 4 - roller length counter, 5 - rope, 6 - spherical metal weight, 7 - shipborne platform, 8 - data cable, 9 - control and calculation terminal, 10 - communication module, L0 - fixed rope length of the pull rope outside the water surface, h0 - water depth of the calibration environment, 2R - diameter of the spherical metal weight. Detailed implementation manners

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below, so that those skilled in the art can better understand the advantages and features of the present invention, and thus make a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention.

[0034] See Figure 1 As shown, a shipborne water depth measuring device based on Archimedes' law includes a tension sensor 1, a U-groove fixed pulley 2, a servo motor 3, a roller length counter 4, a rope 5, a spherical metal weight 6, a shipborne platform 7 and a data cable 8; wherein the tension sensor 1, the U-groove fixed pulley 2, the servo motor 3 and the roller length counter 4 are sequentially fixedly installed on the shipborne platform 7 and are connected by the rope 5.

[0035] Further, the servo motor 3 is used to pull the spherical metal weight 6. One end of the tension sensor 1 is fixed on the shipboard platform 7 and is used to record the tension under different buoyancy states. The U-groove fixed pulley 2 is installed at one end of the tension sensor and is used to transmit the rope. The roller counter 4 is installed at the tail of the shipboard platform and is used to record the total length of the rope transmitted. The spherical metal weight 6 is placed at the end of the rope 5 and is used to pull the rope 5 to sink into the water.

[0036] In the present invention, it further includes a control and calculation terminal 9 and a communication module 10. The control and calculation terminal 9 is used to receive measurement data and perform calculations, preferably a microcomputer or a single-chip microcomputer. The communication module 10 is used to transmit the measurement data to the calculation and control terminal, including at least one of 3G / 4G / 5G, Wi-Fi components or Bluetooth modules. The recorded data is transmitted to the communication module 10 in a wired signal manner using the data line 8. The recorded data is transmitted to the control and calculation terminal in a wireless signal manner. That is to say, in the present invention, through wireless and wired transmission methods, the information interaction between the tension sensor 1, the servo motor 3, the roller counter 4, the control and calculation terminal 9, and the communication module 10 is completed.

[0037] In the present invention, a tension sensor 1 is adopted to measure the tension received by the rope. A spherical metal weight 6 is used to pull the rope to sink directly to the bottom of the water, which can effectively reduce the influence of river bottom silt on the measurement accuracy, and at the same time can eliminate the influence of the occlusion of waterweeds, fish schools and other factors on the measurement process and the accuracy of the results.

[0038] Further, in the present invention, according to Archimedes' law, the corresponding relationship between the tension recorded by the tension sensor and the rope length recorded by the roller counter is calibrated under different buoyancy balance states, and based on this, accurate water depth measurement is realized in the actual measurement environment.

[0039] The method for measuring the shipboard water depth using the above device in the whole invention includes a calibration process and an actual measurement process.

[0040] The following is a detailed introduction and description of the device and measurement method by taking an example of a spherical metal weight with a mass m = 1 kg and a radius R = 0.05 m, and a tension sensor with a range of 20 N.

[0041] Example 1: Calibration process

[0042] Take water from the water area to be measured and inject it into a pool or a bucket to construct a calibration environment. Install the shipboard water depth measurement device based on Archimedes' law on the shipboard platform, and then place the shipboard platform on the water surface of the calibration environment. Release the rope by controlling the servo motor, and the spherical metal weight pulls the rope to sink into the water until it touches the bottom of the calibration environment. At this time, the state is defined as the buoyancy balance state 0, asFigure 2 As shown in the left figure, no measurement data is recorded.

[0043] Under the condition of buoyancy balance state 0, the spherical metal heavy object is no longer affected by the tensile force, and the buoyancy, gravity and bottom support force it receives reach a force balance. At this time, the buoyancy received by the spherical metal heavy object can be calculated according to Archimedes' principle: F 浮 = ρ 水 gV = 1000×10×5.23×10 -4 ≈5.23N. Among them, ρ water is the water density of the measurement environment (here taking 1000 kg / m 3 as an example); g is the acceleration due to gravity (here taking 10 m / s 2 ); V is the volume of the heavy object, which is calculated according to the radius of the heavy object: V = 4πR 3 / 3 = 4×3.14×(0.05) 3 / 3 = 5.23×10 -4 m 3 . According to the buoyancy analysis at this time, it can be known that if the servo motor retrieves the rope with a tensile force F 拉 > G - F 浮 = 10 - 5.23 = 4.77N, the spherical metal heavy object can be pulled away from the bottom of the water. Among them, G is the gravity of the metal heavy object, which is calculated from the mass of the heavy object: G = mg = 1×10 = 10N.

[0044] Therefore, in order to achieve the state where the rope is taut and the metal heavy object is not pulled up, it is necessary to control the servo motor to retrieve the rope with a force less than 4.77N, such as F 拉 = 4N; at the same time, observe the state of the rope in the calibrated water environment until the rope is taut and the heavy object is not pulled up, which is defined as buoyancy balance state I, as Figure 2 shown in the middle figure. No measurement data of the roller counter is recorded in this state; according to the principle of pulley operation, the tensile force shown by the tensiometer at this time is F min = 2×F 拉 = 8N, and record this critical tensile force value. Then control the servo motor to gradually increase the tensile force and observe the floating state of the spherical metal heavy object until it just detaches from the bottom of the water, such as 1 cm from the bottom of the water, as Figure 2 shown in the right figure. At this time, it is defined as buoyancy balance state II. Record the critical tensile force shown by the tensiometer at this time, such as F max = 10N; record the total length of the released rope shown by the roller counter, such as L Ⅱ = 0.8m.

[0045] Measure the actual water depth of the calibrated environment, such as h0 = 0.5m. At this time, the fixed rope length from the roller counter to the water surface in the case of buoyancy balance state II can be calculated: L0 = L II-h0 + 2R = 0.8 - 0.5 - 2×0.05 = 0.2 m, record the calculated value of the fixed rope length.

[0046] At this time, the calibration process can be completed. This process mainly realizes two sets of critical tensile forces F min = 8 N, F max = 10 N, and the calibration of the fixed rope length L0 = 0.2 m outside the water surface, and store these three sets of data in the program of the control and calculation terminal. During the measurement process of the actual water body, the two sets of critical tensile force values are used to judge and control the suspension state of the spherical metal weight inside the water body, and the fixed rope length value outside the water surface is used to calculate the actual water depth.

[0047] Example 2: Actual measurement process

[0048] After the calibration process is completed, place the device on the water surface to be measured and carry out the water depth measurement task in the actual measured water body. As Figure 3 shown, at this time, the spherical metal weight is in a suspended state completely above the water surface and is not affected by the buoyancy force. Before starting the measurement, complete the communication between the display data of the tensiometer, the reading of the roller counter, and the control commands of the servo motor and the control and calculation terminal. This process can be completed through 3G / 4G / 5G, Wi-Fi components or Bluetooth modules.

[0049] Then, send commands through the control and calculation terminal to control the boat to travel to the water area to be measured. Send commands to control the servo motor to release the rope. As Figure 4 shown, at the same time, observe the total length data of the rope released transmitted by the roller counter and the reading of the tensiometer on the control and calculation terminal.

[0050] When the reading of the tensiometer no longer changes, it can be judged that the spherical metal weight has sunk to the bottom of the water, that is, the float reaches the buoyancy balance state 0. As Figure 5 shown, at this time, send a stop command to the servo motor.

[0051] Subsequently, send commands to control the servo motor to recover the rope with a force less than 8 N (i.e., F min ); this process is judged by the tensile force value recorded and transmitted by the tensile sensor; during this process, monitor the rope length reading recorded and transmitted by the roller counter until the reading no longer changes, that is, it can be judged that the rope is straightened and the spherical metal weight reaches the buoyancy balance state I where it is not pulled up. As Figure 6 shown.

[0052] Then, send commands to increase the tensile force of the servo motor, that is, F 拉 ≥F max = 10 N, until the moment when the rope length reading of the roller counter starts to change, send commands to stop the rotation of the servo motor. At this time, the spherical metal weight is just pulled up, that is, it reaches the buoyancy balance state II.Figure 7 . Record the total rope length reading transmitted by the roller counter at this time, such as L i = 2m. Combining with the previously calibrated fixed rope length L0 = 0.2m outside the water surface, the actual water depth can be calculated: h i = L i -L0 + 2R = 2 - 0.2 + 2×0.05 = 1.7m.

[0053] Conclusion: Compared with non-contact water depth measurement technologies such as sonar, radio, and laser, the present invention uses a roller counter and a tension sensor to convert the mechanical movement of a spherical metal weight into quantifiable displacement data, and thus achieves precise water depth measurement. The present invention can effectively avoid the interference of common factors such as river bottom silt, water plants, and fish schools on the measurement accuracy, and is applicable to precise water depth measurement work in different water areas such as rivers, lakes, and shallow seas. This method and device design have the characteristics of high precision, low cost, and easy deployment, and can achieve fast and accurate water depth measurement.

[0054] The above embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. An on-board water depth measuring device based on Archimedes' law, characterized in that: It includes a tensile force sensor (1), a U-groove fixed pulley (2), a servo motor (3), a roller length meter (4), a rope (5), a spherical metal weight (6), a shipborne platform (7) and a data line (8); the tensile force sensor (1), the U-groove fixed pulley (2), the servo motor (3) and the roller length meter (4) are sequentially and fixedly installed on the shipborne platform (7) and are connected by the rope (5); the spherical metal weight (6) is connected to the end of the rope (4) and pulls the rope (5) to sink into the water body to be measured; among them, the tensile force sensor (1), the servo motor (3) and the roller length meter (4) are electrically connected through the data line (8).

2. The on-ship water depth measuring device based on Archimedes' law according to claim 1, wherein: The tensile force sensor (1) is used to measure the tensile force of the spherical metal weight (6) under different buoyancy states.

3. The shipborne water depth measuring device based on Archimedes' law according to claim 1, characterized in that: The roller length meter (4) is used to measure the length of the rope retraction and release.

4. The on-board water depth measuring device based on Archimedes' law according to claim 1, characterized in that: The servo motor (3) is used to provide power for retracting and releasing the rope (5).

5. A shipborne water depth measurement method based on Archimedes' law, characterized in that: The method includes a calibration process and an actual measurement process; wherein the calibration process is to calibrate the critical tensile force values F min , F max , and the fixed rope length L0 outside the water surface; the actual measurement process is to use the calibrated critical tensile force value, the fixed rope length outside the water surface, and the total rope length L i actually measured on site to obtain the calculated value of the water depth h i .

6. The shipborne water depth measurement method based on Archimedes' law according to claim 5, characterized in that: The specific steps of the calibration process are as follows: Step 1: Construction of the calibration environment After filling water in a pool or a bucket to construct the calibration environment, install the shipborne water depth measuring device based on Archimedes' law described in any one of claims 1-4 on the shipborne platform, then place the shipborne platform on the water surface of the calibration environment, and pull the rope (5) through the spherical metal weight (6) until it touches the bottom of the calibration environment; Step 2: Realization of the calibration process Under the calibration environment, the spherical metal weight (6) is recovered by the servo motor (3), and at the same time, the state of the rope (5) is observed until it is straightened, which is recorded as the buoyancy balance state I, and the pulling force value at this time is recorded as F min ; Subsequently, gradually increase the pulling force until the spherical metal weight just breaks away from the bottom of the water, which is recorded as the buoyancy balance state II, and record the pulling force value at this time as F max and the total rope length L recorded by the roller counter II , and measure the actual water depth value h0 at this time.

7. The shipborne water depth measurement method based on Archimedes' law according to claim 6, characterized in that: By subtracting the actual water depth from the recorded total rope length, the fixed rope length outside the water surface can be calibrated: L0 = L II - h0 + 2R, where R represents the radius of the spherical metal weight. At this time, the calibration of the tensile force values and the fixed rope length outside the water surface under two critical states is completed.

8. The shipborne water depth measurement method based on Archimedes' law according to claim 6 or 7, characterized in that: The specific steps of the actual measurement process are as follows: Step 3: Operation process of actual measurement During the actual measurement in the water area, after the spherical metal weight touches the bottom at the measurement point, the spherical metal weight is retrieved with a pulling force less than F min until the rope length no longer changes, that is, until the buoyancy balance state Ⅰ is reached; then the pulling force is gradually increased until F max is reached, that is, until the buoyancy balance state Ⅱ is reached, and the rope length L i is recorded by the roller odometer at this time; Step 4: Calculation process of actual measurement The actual water depth at the measurement point is calculated by subtracting the calibrated fixed rope length outside the water surface from the recorded rope length: h i = L i - L0 + 2R, where L i is the rope length actually measured in step 3, the subscript i represents the i-th measurement point, and L0 is the calibrated fixed rope length outside the water surface in step 2.

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