Pressure wave measuring instrument metering calibration device and method

Abstract

The application discloses a pressure type wave measuring instrument metering calibration device and method, relates to the technical field of hydrological measuring instrument calibration, and comprises the following steps: a wave simulation device drives a lifting platform to make periodic lifting movement according to a set wave height and a wave period, wave height measurement values of the pressure type wave measuring instrument and water depth measurement values of an echo sounder are collected; the water depth measurement values are converted into water depth standard values according to a correction value fitting function of the echo sounder; wave height standard values are calculated from the water depth standard values of each period, and an arithmetic average value is obtained as a standard wave height; the wave height measurement values are subjected to arithmetic averaging, and the difference between the arithmetic average value and the standard wave height is a wave height indication error. The lifting platform is driven to move again, a time interval corresponding to adjacent wave crests or troughs collected by the pressure type wave measuring instrument is taken as a wave period measurement value, a time interval corresponding to adjacent movement turning points of the lifting platform is taken as a wave period standard value, arithmetic average values are respectively obtained, and a difference value is taken as a wave period indication error.

Description

Technical Field

[0001] This invention belongs to the field of hydrological measurement instrument calibration technology, and particularly relates to a calibration device and method for a pressure wave measuring instrument. Background Technology

[0002] Waves are one of the most fundamental elements of hydrology and a common natural phenomenon in oceans and estuaries. A pressure wave meter is a hydrological instrument that measures wave height and period by sensing the pressure changes of the water surface relative to the seabed using a pressure sensor. It is considered an ideal instrument for measuring waves in harsh marine environments and is widely used in engineering wave observation and marine disaster prevention and mitigation. It has a significant impact on the marine economy, the development and utilization of marine resources, maritime military activities, and the site selection, structural design, construction, and daily operation of waterway engineering projects.

[0003] In 2018, Tian Weimin proposed a calibration device for a pressure-type wave and tide meter in his paper "Research on Calibration and Verification Device". This device mainly consists of three parts: a hydraulic system, a piping system, and a closed container comparison system. In this device, the wave height is measured using an invar scale. The hydraulic system provides the power to simulate the vertical motion of the standard wave and controls the motion cycle. The standard water level is represented by the water level in a transparent pipe connected to the bottom of the well. A camera automatically tracks the water level and reads the invar scale value to obtain the highest and lowest standard water levels, thus calculating the standard wave height. The wave period is measured using a digital angular velocity encoder. The reciprocating change of the water level for a given period is powered by a motor, and the motor speed is measured by the digital angular velocity encoder. This device has the following shortcomings: First, the supporting facilities are over 10 m high, and the standard is fixedly connected to the supporting facilities, making disassembly and installation difficult when the standard is sent to a higher-level metrological calibration institution, resulting in significant traceability challenges. Second, the device introduces a large number of uncertainty components during the calibration process, leading to a relatively large measurement uncertainty in the calibration results.

[0004] In 2015, Yao Yilong proposed a wave / tide testing and verification system device in his invention patent "Wave / Tide Testing and Verification System Device and Its Application." This device includes a power system, a measurement and control system, and key auxiliary mechanisms. The measurement and control system and the power system cooperate, using a traction auxiliary mechanism to drag the carrying platform in the vertical direction to simulate wave motion. The device uses an absolute encoder and a rotary encoder as metrological standards, together forming a speed-position dual feedback control system. However, the permanent magnet synchronous traction machine is large and fixedly installed on top of the device, making it difficult to trace the key values ​​for measuring its precision. This makes it difficult to confirm the errors introduced by factors other than the rotational speed of the permanent magnet synchronous traction machine during wave period conversion, resulting in a certain degree of error in the standard wave period provided by the device.

[0005] In summary, existing calibration technologies for pressure wave measuring instruments suffer from several problems, including difficulty in sending standard instruments for testing, incomplete traceability of wave height and wave period values, and low accuracy of calibration results.

[0006] Therefore, there is an urgent need for a technical solution that can solve the above technical problems. Summary of the Invention

[0007] To solve the above-mentioned technical problems, the present invention proposes a pressure wave measuring instrument calibration device, comprising: a wave height calibration device and a wave period calibration device; The wave height calibration device includes a wave tower, a wave simulation device, and an echo sounder. A pressure wave measuring instrument is fixed above the lifting platform of the wave simulation device, and the echo sounder is fixed below the lifting platform with its emission surface facing the bottom of the wave tower. Both the pressure wave measuring instrument and the echo sounder are submerged in the water in the wave tower. The wave simulation device drives the lifting platform to move up and down. The wave period calibration device includes the wave tower, the wave simulation device, and a time measurement system. The time measurement system includes a laser valve, a sensing bar, and a digital oscilloscope. The pressure wave measuring instrument is fixed above the lifting platform, the sensing bar is fixed to the lifting platform, and the laser valve is installed above the water surface on the side wall of the wave tower. The output end of the laser valve is connected to the input end of the digital oscilloscope. The wave simulation device drives the lifting platform to move up and down to simulate wave motion. The sensing bar periodically passes through the laser valve with the lifting platform. The digital oscilloscope detects the jumps in the output voltage of the laser valve and records the first time interval when the sensing bar is below the laser valve and the second time interval when the sensing bar is above the laser valve in each cycle.

[0008] Furthermore, the wave simulation device includes: Host computer, programmable logic controller, servo motor, chain, gear, shock absorber, fixed pulley and lifting platform; The host computer is connected to the programmable logic controller (PLC) via Ethernet. The output of the PLC is connected to the input of the servo motor. The servo motor is connected to the chain via gears. The chain is in contact with the shock absorber. The fixed pulley supports the lower end of the chain. The lifting platform is fixedly connected to the chain. The fixing rod is welded to the top of the lifting platform.

[0009] Furthermore, the host computer transmits the set wave height and wave period parameters to the programmable logic controller via Ethernet. The programmable logic controller controls the speed of the servo motor according to the wave period parameter and controls the rotation angle of the servo motor in each half cycle according to the wave height parameter, so that the servo motor drives the chain to rotate clockwise and counterclockwise alternately, thereby driving the lifting platform to perform periodic lifting and lowering movements. The shock absorber rod restricts the lateral displacement of the lifting platform during the simulated wave motion, ensuring that the lifting platform only moves vertically.

[0010] This invention also proposes a metrological calibration method based on a pressure-type wave measuring instrument calibration device, comprising: a wave height indication error calibration step and a wave period indication error calibration step. The wave height indication error calibration step includes: the wave simulation device drives the lifting platform to perform periodic lifting and lowering motion according to the set wave height parameters and wave period parameters to simulate wave motion; the wave height measurement value of the pressure wave measuring instrument and the water depth measurement value of the echo sounder are collected; the water depth measurement value is converted into a water depth standard value according to the pre-obtained correction value fitting function of the echo sounder; the wave height standard value of each period is calculated according to the water depth standard value of each period; the arithmetic mean of the wave height standard values ​​of each period is calculated as the standard wave height; the arithmetic mean of the wave height measurement values ​​of each wave measured by the pressure wave measuring instrument is calculated; and the difference between the arithmetic mean of the wave height measurement values ​​and the standard wave height is taken as the wave height indication error. The wave period indication error calibration step includes: driving the lifting platform to perform periodic lifting and lowering movements according to the set wave height parameters and wave period parameters through the wave simulation device; calculating the standard value of the wave period based on the first time interval and the second time interval; calculating the arithmetic mean of the standard value of the wave period for each period as the standard wave period; calculating the arithmetic mean of the wave period measurement value of the pressure wave measuring instrument for each period; and calculating the wave period indication error based on the arithmetic mean of the wave period measurement value and the standard wave period.

[0011] Furthermore, the pre-obtained correction value fitting function for the echo sounder includes: calibrating the echo sounder to obtain the indication error at each depth sounding calibration point; taking the negative of the indication error at each depth sounding calibration point to obtain the water depth correction value at each depth sounding calibration point; and performing linear fitting on the water depth measurement value at each depth sounding calibration point and the corresponding correction value to obtain the correction value fitting function. in, This is the water depth correction value. The water depth measurement value is... The slope coefficients are for linear fitting. These are the intercept coefficients for the linear fit; Converting the measured water depth values ​​into standard water depth values ​​includes: in, This refers to the standard value for water depth.

[0012] Furthermore, the calculation of the wave height standard value for each period based on the aforementioned water depth standard value includes: in, For the first The standard value of the wave height of each wave. For the first The maximum value of the standard water depth in each wave. For the first The minimum value of the standard water depth in each wave.

[0013] Furthermore, calculating the arithmetic mean of the wave height measurements from the pressure wave measuring instrument for each period also includes: The experimental standard deviation for calculating wave height measurements: in, The experimental standard deviation of the wave height measurement value. The number of waves; Determine whether the wave height measurement values ​​for each period are outliers. Then determine For outliers in wave height measurements, Remove them, and recalculate the arithmetic mean of the remaining wave height measurements, where, This is the current wave height measurement. This is the threshold for outlier values ​​in wave height measurements.

[0014] Furthermore, calculating the standard value of the wave period based on the first time interval and the second time interval includes: in, For the first The standard value of the wave period of a wave. For the first The first time interval of the wave, For the first The second time interval of the wave.

[0015] Furthermore, the error in calculating the wave period indication based on the arithmetic mean of the measured wave period values ​​and the standard wave period includes: in, For wave period indication error, The arithmetic mean of the wave period measurements is... This is the standard wave period.

[0016] Furthermore, before calculating the arithmetic mean of the wave period measurements from the pressure wave measuring instrument for each period, the process also includes: The experimental standard deviation for calculating wave period measurements: in, The experimental standard deviation of the wave period measurement value. The number of wave cycles; Determine whether the measured wave period value is an outlier. Then determine For outliers in the wave period measurement, Remove, and recalculate the arithmetic mean of the remaining wave period measurements, wherein, This is the measured value of the current wave period. The threshold value for outlier values ​​in wave period measurements.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects: (1) The standard is flexible and easy to install. The echo sounder and digital oscilloscope are independent of the wave simulation device and can be easily removed from the lifting platform. The entire device can be sent for inspection without disassembling, which significantly reduces the difficulty of inspection and the cost of traceability.

[0018] (2) High accuracy of calibration results. The echo sounder uses a linear fitting correction function to correct the measured value before calculating the standard wave height, which effectively reduces the system error; the time measurement system uses the voltage jump of the laser valve to directly measure the time interval, which introduces fewer external interference factors and has low measurement uncertainty.

[0019] (3) Effective removal of outlier data. Outlier values ​​were identified and removed from the measurement results of wave height and wave period, ensuring the reliability of the calibration results.

[0020] (4) Full range coverage. The calibration range covers the typical range of actual wave height (0.5 m to 7 m) and wave period (5 s to 30 s), realizing full range calibration of the pressure wave measuring instrument. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a wave height calibration device; Figure 2 This is a schematic diagram of a wave period calibration device; Figure 3 This is a schematic diagram of a wave tank; Figure 4 This is a schematic diagram of the host computer. Figure 5 This is a schematic diagram of the lifting platform entering the water.

[0022] The attached figures are labeled as follows: 1—Wave tower, 2—Host computer, 3—Programmable logic controller, 4—Servo motor, 5—Chain, 6—Shock absorber, 7—Pulley, 8—Lifting platform, 9—Echo sounder, 10—Pressure wave measuring instrument, 11—Fixed rod, 12—Control software, 13—Digital oscilloscope, 14—Laser valve, 15—Sensing strip. Detailed Implementation

[0023] Example 1 This embodiment proposes a calibration device for a pressure wave measuring instrument, which specifically includes the following components: a wave height calibration device and a wave period calibration device; like Figure 1 As shown, the wave height calibration device includes a wave tank 1 (such as...). Figure 3 As shown), a wave simulation device and an echo sounder are used. A pressure wave measuring instrument 10 is fixed above the lifting platform of the wave simulation device, and the echo sounder 9 is fixed below the lifting platform with its emitting surface facing the bottom of the wave tank, so that both the pressure wave measuring instrument and the echo sounder are submerged in the water of the wave tank (as shown). Figure 5 As shown in the figure, the wave simulation device drives the lifting platform to perform lifting and lowering movements; like Figure 2 As shown, the wave period calibration device includes the wave tower, the wave simulation device, and a time measurement system. The time measurement system includes a laser valve 14, a sensing strip 15, and a digital oscilloscope 13. The pressure wave measuring instrument is fixed above the lifting platform, the sensing strip is fixed to the lifting platform, the laser valve is installed above the water surface on the side wall of the wave tower, and the output end of the laser valve is connected to the input end of the digital oscilloscope. The wave simulation device drives the lifting platform to move up and down to simulate wave motion. The sensing strip periodically passes through the laser valve with the lifting platform. The digital oscilloscope detects the jumps in the output voltage of the laser valve and records the first time interval when the sensing strip is below the laser valve and the second time interval when the sensing strip is above the laser valve in each cycle.

[0024] Specifically, the wave simulation device includes: Host computer 2 (e.g.) Figure 4(As shown), programmable logic controller 3, servo motor 4, chain 5, gear, shock absorber 6, fixed pulley 7, and lifting platform 8; The host computer is connected to the programmable logic controller via Ethernet. The output terminal of the programmable logic controller is connected to the input terminal of the servo motor. The servo motor is connected to the chain via the gear. The chain is in contact with the shock absorber. The fixed pulley supports the lower end of the chain. The lifting platform is fixedly connected to the chain. The fixing rod 11 is welded to the top of the lifting platform.

[0025] Specifically, the host computer transmits the set wave height and wave period parameters to the programmable logic controller via Ethernet. The programmable logic controller controls the speed of the servo motor according to the wave period parameter and controls the rotation angle of the servo motor in each half cycle according to the wave height parameter, so that the servo motor drives the chain to rotate clockwise and counterclockwise alternately, thereby driving the lifting platform to perform periodic lifting and lowering movements. The shock absorber rod restricts the lateral displacement of the lifting platform during the simulated wave motion, ensuring that the lifting platform only moves vertically.

[0026] Example 2 This embodiment proposes a calibration method based on a pressure wave measuring instrument calibration device, including a wave height indication error calibration step, which includes: the wave simulation device driving the lifting platform to perform periodic lifting and lowering motion according to set wave height parameters and wave period parameters to simulate wave motion; collecting the wave height measurement value of the pressure wave measuring instrument and the water depth measurement value of the echo sounder; converting the water depth measurement value into a water depth standard value according to a pre-obtained correction value fitting function of the echo sounder; calculating the wave height standard value for each period according to the water depth standard value for each period; calculating the arithmetic mean of the wave height standard values ​​for each period as the standard wave height; calculating the arithmetic mean of the wave height measurement values ​​of the pressure wave measuring instrument for each period; and taking the difference between the arithmetic mean of the wave height measurement values ​​and the standard wave height as the wave height indication error.

[0027] This embodiment describes the wave height indication error calibration steps through the following procedures: Step a: Construct a wave height calibration device. This device consists of three parts: a wave tower, a wave simulation device, and an echo sounder.

[0028] (1) Wave water tower: height not less than 10 m, inner diameter not less than 3 m, filled with tap water, water depth 9 m.

[0029] (2) Wave Simulation Device: Composed of a host computer, a programmable logic controller (PLC), a servo motor, a chain, gears, shock absorbers, fixed pulleys, and a lifting platform. The host computer is connected to the PLC via Ethernet. The output of the PLC is connected to the input of the servo motor. The servo motor is connected to the chain via gear meshing. The chain is in contact with the shock absorbers. The fixed pulleys support the lower end of the chain. The lifting platform is fixedly connected to the chain, and a fixed rod is welded to the top of the lifting platform. Wave height and wave period parameters are input into the host computer, and the command is transmitted to the PLC via Ethernet. The PLC controls the servo motor to rotate according to the set parameters. The servo motor drives the chain to rotate repeatedly clockwise / counterclockwise, driving the lifting platform to perform periodic lifting and lowering movements according to the set parameters to simulate wave motion. The shock absorbers prevent the lifting platform from swaying left and right during the simulated wave motion, ensuring that the lifting platform only moves vertically. The wave height simulation range of the lifting platform is 0 m to 9 m, and the wave period simulation range is 0 s to 30 s.

[0030] (3) Echo sounder: calibrated by the National Waterway Engineering Testing Equipment Metrology Station, the calibration results are shown in Table 1. The inverse of the indication error at each calibration point was taken to obtain the correction value for each calibration point; the least squares method was used to correct the water depth measurement values ​​at each calibration point. and corresponding correction values Perform a linear fit (such as the least squares method) to obtain the fitting function of the correction value with respect to the water depth measurement value: In formula (1): This is the water depth correction value; The water depth measurement value is from an echo sounder; , These are the slope coefficient and intercept coefficient of the linear fit, respectively. In this embodiment, the fitting result is... , The calibration results of the echo sounder are shown in Table 1, namely: Table 1. Echo Sounder Calibration Results Step b: Place the pressure wave measuring instrument above the lifting platform and use cable ties to secure it to the fixed rod of the lifting platform.

[0031] Step c: Place the echo sounder below the lifting platform and secure it to the platform's fixed pole using cable ties, ensuring the echo sounder's emitting surface faces the bottom of the wave tank. The echo sounder moves up and down synchronously with the lifting platform, its emitting surface always facing the bottom of the tank. The measured water depth (i.e., the distance from the instrument to the bottom of the tank) changes periodically with the platform's movement, and the amplitude of this change corresponds to the equivalent wave height of the water pressure change experienced by the calibrated instrument.

[0032] Step d: Connect the echo sounder to the control software 12 and set the data sampling frequency to 10 Hz.

[0033] Step e: Set the height of the lifting platform on the host computer so that the echo sounder and the pressure wave measuring instrument are completely submerged in the water.

[0034] Step f: Set the wave period to 8 s and the number of simulated waves to 10 on the host computer. Set the wave height to 0.5 m, 3 m, 5 m and 7 m in sequence. Start the lifting platform after each setting to complete the calibration data acquisition of each wave height under the condition of wave period of 8 s.

[0035] Step g: Set the wave period to 20 s and the number of simulated waves to 10 on the host computer. Set the wave height to 0.5 m, 3 m, 5 m and 7 m in sequence. Start the lifting platform after each setting to complete the calibration data acquisition of each wave height under the condition of wave period of 20 s.

[0036] Step h: Connect the pressure wave measuring instrument to the control software, export the wave height measurement data, and the measurement results are shown in Table 2.

[0037] Table 2 Wave height measurement values ​​of pressure wave measuring instrument Step i: Use the Laida criterion to identify outliers in each group of wave height measurements. Calculate the arithmetic mean of the wave height measurements using the following formula: In formula (2): The arithmetic mean of the wave height measurements; For the first The wave height measurement of each wave; The number of waves.

[0038] The experimental standard deviation of wave height measurements is calculated using the following formula: In formula (3): This represents the experimental standard deviation of the wave height measurement.

[0039] For suspicious values Anomaly detection is performed using the following formula. If the formula is true, the suspicious value is considered an anomaly and is removed: In equation (4): For abnormal values ​​in wave height measurement, The threshold for outliers in wave height measurements (for example, It can be 3).

[0040] Taking the measurement results with a wave period of 8 s and a wave height setting of 1 m as an example: the result calculated from equation (2) is as follows: m, calculated from equation (3) m, the largest difference between the 10 measured values ​​and the arithmetic mean is 1.004 m. Substituting this value into equation (4) yields: Therefore, 1.004 m is not an outlier. Following the steps above, all wave height measurement results were evaluated sequentially, and no outliers were found. After removing the outliers, the arithmetic mean of each group of wave height measurements was recalculated according to formula (2) and used as the wave height measurement result of the pressure wave measuring instrument. The results are shown in Table 3.

[0041] Table 3. Arithmetic mean of wave height measurements from a pressure-type wave meter. Step j: Connect the echo sounder to the control software and export the data log file. Enter the water depth measurements from the data log file. Substituting into equation (1) yields the correction value. Then and Substituting into the following formula, we obtain the standard value of water depth: In formula (5): This refers to the standard value for water depth. The water depth measurement value is from an echo sounder; The water depth correction value is calculated by equation (1). It changes periodically over time.

[0042] Step k: Take the maximum and minimum values ​​of each period in the water depth standard value sequence, and calculate the value of the first period using the following formula. Standard value of wave height for each cycle: In formula (6): For the first Standard wave height value for each depth measurement cycle; For the first The maximum value of the standard water depth in a water depth measurement cycle; For the first The minimum standard value of water depth in each water depth measurement cycle and the calculation results of the standard value of wave height in each cycle are shown in Table 4.

[0043] Table 4 Standard values ​​of wave height Step 1: Calculate the arithmetic mean of the standard values ​​of wave height for each period using the following formula, and use this as the measurement result of the standard wave height: In equation (7): The arithmetic mean of the standard wave height values ​​(standard wave height); In this embodiment, the number of water depth measurement cycles is [number]. The calculation results are shown in Table 5.

[0044] Table 5 Standard wave height measurement results Step m: Calculate the arithmetic mean of the wave height measurements obtained from the pressure wave meter in step i. The arithmetic mean of the standard wave height values ​​obtained in step 1 Substitute into the following formula to calculate the wave height indication error and complete the wave height indication error calibration: In equation (8): This refers to the wave height indication error of the pressure wave meter; The arithmetic mean of the wave height measurements from the pressure wave meter; The arithmetic mean of the standard wave height values ​​is given in Table 6. The calibration results are shown in Table 6.

[0045] Table 6. Calibration Results of Wave Height Indication Error Example 3 This embodiment proposes a metrological calibration method based on a pressure wave measuring instrument calibration device, including a wave period indication error calibration step, which includes: driving the lifting platform to perform periodic lifting and lowering movements according to set wave height parameters and wave period parameters through the wave simulation device; calculating a standard wave period value based on the first time interval and the second time interval; calculating the arithmetic mean of the standard wave period values ​​for each period as the standard wave period; calculating the arithmetic mean of the wave period measurement values ​​of the pressure wave measuring instrument for each period; and calculating the wave period indication error based on the arithmetic mean of the wave period measurement values ​​and the standard wave period.

[0046] This embodiment describes the wave period indication error calibration procedure through the following steps: Step a: Construct a wave period calibration device. This device consists of three parts: a wave tower, a wave simulation device, and a time measurement system.

[0047] (1) The structure of the wave water tower and wave simulation device is the same as that in Example 2.

[0048] (2) Time Measurement System: Composed of a digital oscilloscope, laser valve, induction bar, and steel tape measure. The laser valve is installed on the side wall of the wave tank. The installation height of the laser valve is adjusted so that the distance from the laser valve to the water surface is 0.050 m (measured by a steel tape measure). The output end of the laser valve is connected to the input end of the digital oscilloscope. The transmitting end of the laser valve continuously emits infrared laser to the receiving end, and the digital oscilloscope continuously records the voltage signal at the output end of the laser valve. The induction bar is fixed to the lifting platform. The cross-sectional shape is "L" shaped, with a diameter of 2 mm and a height of 0.400 m. As the lifting platform moves up and down periodically, the induction bar passes through the laser valve periodically. When the induction bar passes through the laser valve, the laser beam is interrupted, and the output voltage of the laser valve jumps. The digital oscilloscope records the jump times accordingly. In each motion cycle, the lifting platform first moves down and then up. The induction bar passes through the laser valve twice, generating two voltage jump intervals. The time interval from the end of the first jump to the beginning of the second jump is the first time interval when the induction bar is below the laser valve. The time interval between the end of the second transition and the start of the first transition in the next cycle is the second time interval in which the sensing strip is positioned above the laser valve. .

[0049] Step b: Fix the pressure wave measuring instrument to the fixed rod above the lifting platform, and connect the laser valve to the digital oscilloscope.

[0050] Step c: Use the host computer to return the lifting platform to the starting position, i.e., the sensor bar is located 0.150m above the laser valve.

[0051] Step d: Set the wave height to 1 m and the number of simulated waves to 10 on the host computer. Set the wave period to 5 s, 10 s, 15 s, 20 s, and 30 s in sequence. After each setting, start the lifting platform and use a digital oscilloscope to record the time interval data of the induction bar passing through the laser valve in each period.

[0052] Step e: Set the wave height to 3 m and the number of simulated waves to 10 on the host computer. Set the wave period to 5 s, 10 s, 15 s, 20 s, and 30 s in sequence. After each setting, start the lifting platform and use a digital oscilloscope to record the time interval data of the induction bar passing through the laser valve in each period.

[0053] Step f: Export the measurement data from the digital oscilloscope and calculate the following formula: Standard value of wave period for each wave: In equation (9), For the first The standard value of the wave period of a wave. For the first The first time interval of the wave, For the first The second time interval of each wave. Taking the calculation results of the first wave with a wave height of 1 m as an example, as shown in Table 7.

[0054] Table 7 Standard values ​​of the wave period for the first wave (wave height 1 m) Step g: Calculate the arithmetic mean of the standard values ​​of each periodic wave period using the following formula, and use this as the measurement result of the standard wave period: In formula (10): It is the arithmetic mean of the standard values ​​of the wave period (standard wave period). In this embodiment, the number of waves is... The calculation results are shown in Table 8.

[0055] Table 8 Standard Wave Period Measurement Results Step h: Connect the pressure wave measuring instrument to the control software and export the wave period measurement data. The results are shown in Table 9.

[0056] Table 9 Wave period measurement values ​​of pressure wave measuring instrument Step i: Identify outliers for each group of wave period measurements. Calculate the arithmetic mean of the wave period measurements using the following formula: In equation (11): The arithmetic mean of the wave period measurements. For the first The wave period measurement of each wave. The number of waves.

[0057] Calculate the experimental standard deviation of the wave period measurement using the following formula: In equation (12): The experimental standard deviation of the wave period measurement value is given.

[0058] For suspicious values Anomaly detection is performed using the following formula. If the formula is true, the suspicious value is considered an anomaly and is removed: In equation (13): These are outliers in wave period measurements.

[0059] Taking the measurement results with a wave height of 1 m and a wave period setting of 5 s as an example: the result calculated by equation (11) is as follows: s, calculated from equation (12) The largest difference between the 10 measured values ​​and the arithmetic mean is 5.0 s. Substituting this value into equation (13) yields: Therefore, 5.0 s is not an outlier. The above steps were followed to judge all wave period measurement results in sequence, and no outliers were found. After the outliers were removed, the arithmetic mean of each group of wave period measurement values ​​was recalculated according to formula (11) and used as the wave period measurement result of the pressure wave measuring instrument. The results are shown in Table 10.

[0060] Table 10 Arithmetic mean of wave period measurements from a pressure-type wave measuring instrument Step j: Calculate the arithmetic mean of the wave period measurements obtained from the pressure wave measuring instrument in step i. The standard wave period obtained in step g Substitute into the following formula to calculate the wave period indication error and complete the wave period indication error calibration: In the formula: The wave period indication error of the pressure wave measuring instrument is expressed in seconds (s). is the arithmetic mean of the wave period measurements taken by the pressure wave measuring instrument, in seconds; The value is the arithmetic mean of the standard wave period, in seconds. The calibration results are shown in Table 11.

[0061] Table 11. Calibration Results of Wave Period Indication Error The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A calibration device for a pressure-type wave measuring instrument, characterized in that, include: Wave height calibration device and wave period calibration device; The wave height calibration device includes a wave tower, a wave simulation device, and an echo sounder. A pressure wave measuring instrument is fixed above the lifting platform of the wave simulation device, and the echo sounder is fixed below the lifting platform with its emission surface facing the bottom of the wave tower. Both the pressure wave measuring instrument and the echo sounder are submerged in the water in the wave tower. The wave simulation device drives the lifting platform to move up and down. The wave period calibration device includes the wave tower, the wave simulation device, and a time measurement system. The time measurement system includes a laser valve, a sensing bar, and a digital oscilloscope. The pressure wave measuring instrument is fixed above the lifting platform, the sensing bar is fixed to the lifting platform, and the laser valve is installed above the water surface on the side wall of the wave tower. The output end of the laser valve is connected to the input end of the digital oscilloscope. The wave simulation device drives the lifting platform to move up and down to simulate wave motion. The sensing bar periodically passes through the laser valve with the lifting platform. The digital oscilloscope detects the jumps in the output voltage of the laser valve and records the first time interval when the sensing bar is below the laser valve and the second time interval when the sensing bar is above the laser valve in each cycle.

2. The calibration device for a pressure wave measuring instrument as described in claim 1, characterized in that, The wave simulation device includes: Host computer, programmable logic controller, servo motor, chain, gear, shock absorber, fixed pulley and lifting platform; The host computer is connected to the programmable logic controller (PLC) via Ethernet. The output of the PLC is connected to the input of the servo motor. The servo motor is connected to the chain via gears. The chain is in contact with the shock absorber. The fixed pulley supports the lower end of the chain. The lifting platform is fixedly connected to the chain. The fixing rod is welded to the top of the lifting platform.

3. The calibration device for a pressure wave measuring instrument as described in claim 2, characterized in that, include: The host computer transmits the set wave height and wave period parameters to the programmable logic controller via Ethernet. The programmable logic controller controls the speed of the servo motor according to the wave period parameter and controls the rotation angle of the servo motor in each half cycle according to the wave height parameter, so that the servo motor drives the chain to rotate clockwise and counterclockwise alternately, thereby driving the lifting platform to perform periodic lifting and lowering movements. The shock absorber rod restricts the lateral displacement of the lifting platform during the simulated wave motion, ensuring that the lifting platform only moves vertically.

4. A calibration method for a pressure wave measuring instrument based on the calibration device of any one of claims 1-3, characterized in that, include: Wave height indication error calibration steps and wave period indication error calibration steps: The wave height indication error calibration step includes: the wave simulation device drives the lifting platform to perform periodic lifting and lowering motion according to the set wave height parameters and wave period parameters to simulate wave motion; the wave height measurement value of the pressure wave measuring instrument and the water depth measurement value of the echo sounder are collected; the water depth measurement value is converted into a water depth standard value according to the pre-obtained correction value fitting function of the echo sounder; the wave height standard value of each period is calculated according to the water depth standard value of each period; the arithmetic mean of the wave height standard values ​​of each period is calculated as the standard wave height; the arithmetic mean of the wave height measurement values ​​of each wave measured by the pressure wave measuring instrument is calculated; and the difference between the arithmetic mean of the wave height measurement values ​​and the standard wave height is taken as the wave height indication error. The wave period indication error calibration step includes: driving the lifting platform to perform periodic lifting and lowering movements according to the set wave height parameters and wave period parameters through the wave simulation device; calculating the standard value of the wave period based on the first time interval and the second time interval; calculating the arithmetic mean of the standard value of the wave period for each period as the standard wave period; calculating the arithmetic mean of the wave period measurement value of the pressure wave measuring instrument for each period; and calculating the wave period indication error based on the arithmetic mean of the wave period measurement value and the standard wave period.

5. A metrological calibration method as claimed in claim 4, characterized in that, The pre-obtained correction value fitting function for the echo sounder includes: calibrating the echo sounder to obtain the indication error at each depth sounding calibration point; taking the negative of the indication error at each depth sounding calibration point to obtain the water depth correction value at each depth sounding calibration point; and performing linear fitting on the water depth measurement value at each depth sounding calibration point and the corresponding correction value to obtain the correction value fitting function. in, This is the water depth correction value. The water depth measurement value is... The slope coefficients are for linear fitting. These are the intercept coefficients for the linear fit; Converting the measured water depth values ​​into standard water depth values ​​includes: in, This refers to the standard value for water depth.

6. A metrological calibration method as claimed in claim 4, characterized in that, The standard wave height value for each period is calculated based on the standard water depth value for each period, including: in, For the first The standard value of the wave height of each wave. For the first The maximum value of the standard water depth in each wave. For the first The minimum value of the standard water depth in each wave.

7. A metrological calibration method as claimed in claim 6, characterized in that, The arithmetic mean of the wave height measurements from the pressure wave measuring instrument for each period also includes: The experimental standard deviation for calculating wave height measurements: in, The experimental standard deviation of the wave height measurement value. The number of waves; Determine whether the wave height measurement values ​​for each period are outliers. Then determine For outliers in wave height measurements, Remove them, and recalculate the arithmetic mean of the remaining wave height measurements, where, This is the current wave height measurement. This is the threshold for outlier values ​​in wave height measurements.

8. A metrological calibration method as claimed in claim 4, characterized in that, The standard value of the wave period is calculated based on the first time interval and the second time interval, including: in, For the first The standard value of the wave period of a wave. For the first The first time interval of the wave, For the first The second time interval of the wave.

9. A metrological calibration method as claimed in claim 8, characterized in that, The error in calculating the wave period indication based on the arithmetic mean of the measured wave period values ​​and the standard wave period includes: in, For wave period indication error, The arithmetic mean of the wave period measurements is... This is the standard wave period.

10. A metrological calibration method as claimed in claim 9, characterized in that, Before calculating the arithmetic mean of the wave period measurements from the pressure wave measuring instrument for each period, the following steps are also included: The experimental standard deviation for calculating wave period measurements: in, The experimental standard deviation of the wave period measurement value. The number of wave cycles; Determine whether the measured wave period value is an outlier. Then determine For outliers in the wave period measurement, Remove, and recalculate the arithmetic mean of the remaining wave period measurements, wherein, This is the measured value of the current wave period. The threshold value for outlier values ​​in wave period measurements.

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