A segmented ship speed measurement method suitable for arc-shaped navigation tunnel tests

Abstract

The present invention discloses a segmented measurement method for ship speed applicable to arc-shaped navigation tunnel test, which relates to the field of engineering measurement technology, and includes the following steps: dividing the arc-shaped segment of the tunnel into a number of uniform measurement segments, and setting up a laser rangefinder at the front end of each measurement segment; presetting a collection sequence, and sequentially collecting the distance data measured by the laser rangefinder when the test ship is sailing based on the preset collection sequence; based on the distance data measured by the laser rangefinder, obtaining the arc length passed by the test ship at any time along the center line of the waterway; and obtaining the ship speed based on the ratio of the arc length to the time of the test ship's navigation. The present invention provides a ship speed measurement method with strong adaptability, high precision and strong real-time performance for arc-shaped navigation tunnel test through segmented measurement, real-time data collection and speed calculation based on arc length, which solves the shortcomings of the prior art in arc-shaped waterway measurement and has significant practical application value.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering measurement, and in particular relates to a segmented measurement method of ship speed suitable for arc-shaped navigation tunnel testing. Background Art

[0002] In the navigation test model, ship speed measurement is a key link in studying the navigation performance of the waterway and the navigation characteristics of the ship. At present, the commonly used measurement methods are mainly stroboscopic photography speed measurement and radar speed measurement. Stroboscopic photography speed measurement uses a high-speed camera to capture the movement trajectory of the ship under the stroboscopic light, and then calculates its speed. This method has strong applicability and can adapt to waterways of any shape, including straight waterways and curved waterways. However, it also has some obvious shortcomings: first, it needs to be equipped with a high-speed camera, and the equipment cost is relatively high; second, the installation and debugging process is complicated, and the technical level of the operator is required to be high; in addition, because stroboscopic photography speed measurement relies on image processing, it is easily affected by factors such as light and background interference, and the cumulative error is large, which affects the measurement accuracy.

[0003] Radar speed measurement uses the Doppler effect to calculate the radial velocity of a ship by measuring the frequency difference between the radar transmission signal and the echo signal. The advantages of this method are that the equipment is relatively simple, easy to operate, and has high measurement accuracy. However, radar speed measurement has a significant limitation: it is mainly applicable to straight waterways. For the real-time turning of ships in curved waterways, the measurement process becomes complicated and difficult to accurately achieve. At present, there is no effective solution to the problem of radar speed measurement when ships turn in curved waterways.

[0004] In summary, the existing stroboscopic photography and radar speed measurement methods have certain limitations in the arc-shaped navigation tunnel test and cannot meet the measurement requirements of high precision and high efficiency. Therefore, it is of great practical significance to develop a segmented ship speed measurement method suitable for the arc-shaped navigation tunnel test. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a segmented measurement method of ship speed suitable for arc-shaped navigation tunnel tests to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides a method for measuring the speed of a ship in sections suitable for arc-shaped navigation tunnel tests, comprising the following steps:

[0007] The arc section of the tunnel is divided into several uniform measuring sections, and a laser rangefinder is set up at the front end of each measuring section;

[0008] A preset collection sequence is used to sequentially collect distance data measured by a laser rangefinder of the test vessel while it is sailing based on the preset collection sequence;

[0009] Based on the distance data measured by the laser rangefinder, the arc length that the test ship passes along the center line of the channel at any point in time is obtained;

[0010] The ship speed is obtained based on the ratio of the arc length to the sailing time of the test ship.

[0011] Optionally, the process of setting up a laser rangefinder at the front position of each measuring section includes:

[0012] The chord line and chord height of each measuring section are obtained, and the position coordinates of the laser rangefinder are adjusted so that the indicator light of the laser rangefinder passes through the midpoint of the chord height of the corresponding measuring section and is parallel to the chord line of the corresponding measuring section.

[0013] Optionally, the process of sequentially collecting distance data measured by a laser rangefinder of a test vessel while sailing based on a preset collection order includes:

[0014] The distance data measured by each laser rangefinder is detected, and when the measured distance data exceeds the critical value of the corresponding measurement section, the distance data of the next laser rangefinder is automatically collected.

[0015] Optionally, a shielding plate is installed vertically at the stern of the test vessel to shield the measuring indicating laser of the laser rangefinder.

[0016] Optionally, the arc length that the test ship passes along the centerline of the channel at any point in time can be calculated using the following formula:

[0017] ,

[0018] Where l is the arc length of the two points passed by the ship; r is the radius of the centerline of the channel passed by the ship; d2 is the distance from the laser rangefinder to the second point; d1 is the distance from the laser rangefinder to the first point; L0 is the distance from the laser rangefinder to the chord height line of the corresponding measurement section.

[0019] Optionally, the calculation formula for the ship speed is as follows:

[0020] ,

[0021] Where v is the ship speed; l is the length of the arc between the two points the ship passes; t1 is the time the ship passes the first point; t2 is the time the ship passes the second point.

[0022] Optionally, the distribution density of the measurement segments is adaptively adjusted based on the accuracy requirement of the experimental measurement.

[0023] The present invention also provides a computer device, comprising a memory, a processor and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method.

[0024] The present invention also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method are implemented.

[0025] The present invention also provides a computer program product, comprising a computer program, which implements the steps of the method when executed by a processor.

[0026] Compared with the prior art, the present invention has the following advantages and technical effects:

[0027] The present invention divides the arc channel into sections and uses a laser rangefinder to perform section-by-section measurement. This method can effectively solve the problem of measuring the speed of a ship in an arc channel. The traditional radar speed measurement method has the problems of complex measurement and insufficient accuracy in an arc channel. However, this method can accurately measure the speed of a ship in an arc channel through section-by-section measurement and data processing, and has stronger adaptability.

[0028] The present invention divides the arc channel into several measurement sections, and sets up a laser rangefinder at the front end of each measurement section, which can track and measure the navigation track of the ship in sections. This segmented measurement method avoids the measurement error caused by the curvature of the channel in the traditional method, and improves the measurement accuracy, especially in areas where the ship turns or the channel curvature changes greatly.

[0029] The present invention collects the distance data of the laser rangefinder in sequence and transmits it to the detection software system in real time. This real-time data collection and processing mechanism can ensure the timeliness and accuracy of the measured data, provide reliable data support for subsequent speed calculation, and also facilitate the experimenter to monitor the test process in real time.

[0030] The present invention calculates the arc length that the ship passes along the center line of the channel and calculates the speed in combination with the sailing time. This method can more realistically reflect the actual movement state of the ship in the arc channel. Compared with the traditional straight-line distance calculation method, the calculation method based on arc length can more accurately reflect the navigation track and speed change of the ship. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0032] Figure 1 It is a schematic diagram of segmented measurement of a curved navigation tunnel test according to an embodiment of the present invention;

[0033] Figure 2 Schematic diagram of the installation of a laser rangefinder according to an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the installation position of the ship model shielding plate according to an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of arc length calculation according to an embodiment of the present invention;

[0036] Figure 5 It is a schematic diagram of an embodiment of Xiluodu Tunnel navigation segment measurement according to an embodiment of the present invention;

[0037] Among them, 1. test water tank; 2. outer wall of water tank; 3. inner wall of water tank; 4. center line of test channel; 5. laser rangefinder; 6. indicator light emitted by the rangefinder; 7. chord line of segmented arc; 8. chord height line; 9. midpoint of chord height line; 10. ship model shielding plate; 11. ship model. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0040] Embodiment 1

[0041] This embodiment provides a segmented measurement method for ship speed applicable to arc-shaped navigation tunnel tests, including the following on-site measurement implementation steps:

[0042] Step 1: divide the arc section of the tunnel into several uniform measurement sections according to the test requirements;

[0043] Step 2: before the test begins, several laser rangefinders are set up at designated positions and angles outside the arc section of the waterway test tank;

[0044] Step 3: Install a shielding plate at the stern of the test vessel;

[0045] Step 4: After the test starts, the distance data measured by the laser rangefinder is collected in sequence and transmitted to the test detection software system in real time. When the obtained data exceeds the specified range, the distance data of the next laser rangefinder is automatically collected;

[0046] Step 5: Calculate the arc length along the center line of the channel at any point in time using the distance data measured by the laser rangefinder;

[0047] Step six, calculate the ship speed by the ratio of arc length to the sailing time of the test ship.

[0048] As a specific implementation method, the segmented measurement in step 1 is to divide the arc section of the tunnel into several measurement sections according to the test measurement accuracy requirements. The segmentation can be more dense when the accuracy requirements are high, and more sparse when the requirements are not high. Figure 1 The figure shows a schematic diagram of segmented measurement of the arc-shaped navigation tunnel test, including a test water tank 1, a water tank outer wall 2, a water tank inner wall 3 and a test channel centerline 4.

[0049] As a specific implementation method, in step 2, a laser rangefinder is set up at the front end of each measuring section. Figure 2 The figure is a schematic diagram of the installation of the laser rangefinder, including the center line 4 of the test channel, the laser rangefinder 5, the indicator light 6 emitted by the rangefinder, the chord line 7 of the segmented arc, the chord height line 8 and the midpoint 9 of the chord height line. The position coordinates of each laser rangefinder 5 can be pre-drawn in the figure, and the chord line and chord height line 8 of each measuring arc segment are drawn so that the indicator light of the laser rangefinder 5 passes through the midpoint 9 of the chord height line of the segment and is parallel to the chord line of the arc segment. The position of the laser rangefinder 5 can be adjusted according to the actual measuring range of the specific equipment so that the midpoint 9 of the chord height line is at the best measuring position.

[0050] As a specific implementation method, in step 3, a shielding plate is erected at the tail of the test ship to shield the measurement indication laser of the laser rangefinder, see Figure 3 The schematic diagram of the installation position of the ship shielding plate includes a test water tank 1, a laser rangefinder 5, an indication light 6 emitted by the rangefinder, a ship model shielding plate 10, and a ship model 11. The relative position of the laser rangefinder 5 and the ship model shielding plate 10 is adjusted so that when the ship passes through the middle position of the arc segment, the indication light of the laser rangefinder 5 is projected on the bull's eye of the ship model shielding plate 10.

[0051] As a specific implementation method, in step four, when the test is carried out, the distance data measured by each laser rangefinder is collected in sequence according to the order in which the ship passes through each arc segment, and transmitted to the test detection software system in real time. When the data obtained exceeds the distance from the laser rangefinder to the arc segment dividing line, it is regarded as the ship entering the next arc segment, and then the distance data of the next laser rangefinder is automatically collected.

[0052] As a specific implementation method, in step 5, the distance data measured by the laser rangefinder is used to calculate the arc length of any two points passed by the test ship along the center line of the channel. The arc length calculation formula is as follows:

[0053] ,

[0054] In the formula, l is the length of the arc between the two points passed by the ship; r is the radius of the centerline of the channel passed by the ship; d2 is the distance from the rangefinder to the second point; d1 is the distance from the rangefinder to the first point; L0 is the distance from the rangefinder to the chord height line of the arc segment.

[0055] As a specific implementation method, in step 6, the speed is calculated by the arc length and the sailing time of the test ship. The speed calculation formula is as follows:

[0056] ,

[0057] In the formula, v is the ship's speed; l is the length of the arc between the two points the ship passes; t1 is the time it takes for the ship to pass the first point; and t2 is the time it takes for the ship to pass the second point.

[0058] Embodiment 2

[0059] The following embodiment takes the characteristic test of a ship's navigation test on a section of an arc channel in the navigation tunnel of Xiluodu Tunnel as an example:

[0060] The waterway in this test enters a curved waterway with a radius of 33 meters after exiting the straight section. The arc length is 38 meters and the width of the test water tank is 1 meter. The length measurement accuracy of this embodiment test is required to be within 0.2 cm. Since it is impossible to use radar speed measurement on the straight section, if stroboscopic photography is used for speed measurement, a high-speed camera with high cost needs to be installed in the test hall, which is difficult to locate and prone to large cumulative errors. Therefore, a segmented measurement method is adopted.

[0061] Step 1: In this embodiment, the arc-shaped water tank of the tunnel is first divided into five evenly spaced measurement sections, a to e. Figure 5 As shown: the interval distance of each section is P = 6.326 meters (chord length).

[0062] Step 2: Before the test begins, five laser rangefinders C1~C5 are set up on the outer wall of the arc section of the waterway test flume. The laser rangefinder indicates the direction of light emission, that is, the measurement angle and the deflection angle θ of the center line of the straight line segment are respectively 11°, 22°, 33°, 44°, and 55°, and the distance between the rangefinder and the midpoint L0 of the measurement segment is 6.047 meters. In this implementation, the zero point coordinates of the rangefinder are shown in Table 1, where the zero point is set at the starting point of the arc section of the center line of the flume channel:

[0063] Table 1

[0064]

[0065] Step 3: Install a shielding plate at the stern of the test ship. The width of the plate is 0.4m to ensure that the rangefinder indicator light can always hit the shielding plate when the ship is running in the water tank.

[0066] Step 4: After the test begins, collect the distance data measured by the laser rangefinder in the order of C1 to C5 and transmit it to the test detection software system in real time. When the data obtained exceeds the critical value Dmax of the measurement section, automatically collect the distance data of the next laser rangefinder. The critical value Dmax of the measurement section of this test is 9.2m.

[0067] Step 5: Calculate the arc length along the center line of the channel at any point in time according to the distance measured by the laser rangefinder. Figure 4 , l is the length of the arc that the ship model passes through points A and B; r is the radius of the centerline of the channel that the ship model passes through; d B is the distance from the rangefinder to point B; d A is the distance from the rangefinder to point A; L0 is the distance from the rangefinder to the chord height line of the arc segment.

[0068] In this embodiment, the arc lengths of points A and B can be calculated using the following formula:

[0069] ,

[0070] In the formula, l is the length of the arc between the two points the ship passes; r is the radius of the centerline of the channel the ship passes; is the distance from the rangefinder to point B; is the distance from the rangefinder to point A; L0 is the distance from the rangefinder to the chord height line of the arc segment.

[0071] The arc length calculation formula is input into the upper computer software program. In the formula, r in this embodiment is taken as 33000; L0 is taken as 6047. The arc length passed by the test ship along the center line of the channel at any time can be calculated according to the distance data measured by the laser rangefinder. The system software can display the ship speed in real time through the ratio of the arc length to the time of the test ship's navigation.

[0072] Step 6: Calculate the speed by the arc length and the time the test ship sails. By testing the time it takes for the ship to pass through points A and B, the following formula can be used to calculate the ship's speed:

[0073] ,

[0074] In the formula, v is the ship's speed; l is the length of the arc between the two points the ship passes; t A is the time when the ship passes point A; t B is the time when the ship passes point B.

[0075] Table 2 is a set of segment data extracted from the test system at intervals of 10s. The acquisition frequency of this test is 1:

[0076] Table 2

[0077]

[0078] Embodiment 3

[0079] This embodiment further provides a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method.

[0080] Embodiment 4

[0081] This embodiment also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method are implemented.

[0082] Embodiment 5

[0083] This embodiment also provides a computer program product, including a computer program, which implements the steps of the method when executed by a processor.

[0084] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for measuring ship speed in sections suitable for arc-shaped navigation tunnel tests, characterized in that: The following steps are involved: The arc section of the tunnel is divided into several uniform measuring sections, and a laser rangefinder is set up at the front end of each measuring section; A preset collection sequence is used to sequentially collect distance data measured by a laser rangefinder of the test vessel while it is sailing based on the preset collection sequence; Based on the distance data measured by the laser rangefinder, the arc length that the test ship passes along the center line of the channel at any point in time is obtained; The ship speed is obtained based on the ratio of the arc length to the sailing time of the test ship.

2. The method according to claim 1, characterized in that The process of setting up a laser rangefinder at the front position of each measuring section includes: The chord line and chord height of each measuring section are obtained, and the position coordinates of the laser rangefinder are adjusted so that the indicator light of the laser rangefinder passes through the midpoint of the chord height of the corresponding measuring section and is parallel to the chord line of the corresponding measuring section.

3. The method according to claim 1, characterized in that The process of sequentially collecting the distance data measured by the laser rangefinder of the test ship while sailing based on the preset collection order includes: The distance data measured by each laser rangefinder is detected, and when the measured distance data exceeds the critical value of the corresponding measurement section, the distance data of the next laser rangefinder is automatically collected.

4. The method according to claim 3, characterized in that: A shielding plate is installed vertically at the stern of the test ship to block the measuring indication laser of the laser rangefinder.

5. The method according to claim 1, characterized in that The arc length that the test ship passes along the center line of the channel at any point in time is calculated by the following formula: ， Where l is the arc length of the two points passed by the ship; r is the radius of the centerline of the channel passed by the ship; d2 is the distance from the laser rangefinder to the second point; d1 is the distance from the laser rangefinder to the first point; L0 is the distance from the laser rangefinder to the chord height line of the corresponding measurement section.

6. The method according to claim 1, characterized in that The calculation formula for ship speed is as follows: ， Where v is the ship speed; l is the length of the arc between the two points the ship passes; t1 is the time the ship passes the first point; t2 is the time the ship passes the second point.

7. The method according to claim 1, characterized in that The distribution density of the measurement segments is adaptively adjusted based on the accuracy requirements of the experimental measurements.

8. A computer device comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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