A sonar measurement system and a three-dimensional imaging sonar underwater detection method

Abstract

The present invention relates to a sonar measurement system, comprising a sonar and a bracket; the bracket comprises: a mounting platform for mounting the sonar; at least three support rods, each support rod having a first end capable of being constrained at the bottom of the mounting platform; connecting rods, the number of which corresponds to the number of support rods, each connecting rod correspondingly connecting two adjacent support rods; the system is characterized in that the first end of each support rod is constrained to the mounting platform in a manner capable of rotating relative to the mounting platform, and each connecting rod is constrained to the support rod in a manner capable of independently moving up and down along the length direction of the support rod to which it is connected. Also disclosed is a three-dimensional imaging sonar underwater detection method using the above-mentioned sonar measurement system. The support angle of the support rods of the sonar measurement system is adjustable, and by adjusting the position of the connecting rods, the bracket formed by the support rods can be installed stably and can be adjusted according to different three-dimensional imaging requirements to be suitable for terrain with slopes.

Description

Technical Field

[0001] The present invention relates to the technical field of sonar measurement, and in particular to a sonar measurement system and a three-dimensional imaging sonar underwater detection method. Background Art

[0002] my country has a vast territory, numerous rivers, and extensive seas. Natural disasters such as typhoons, floods, and earthquakes have severely damaged hydraulic structures, leading to frequent dike breaches and reservoir failures. To safeguard the national economy and the lives and property of the people, rapid inspection of underwater structures at risk sites is essential to facilitate the development of emergency response and remediation plans. Underwater sonar imaging is a currently available technology for inspecting hydraulic structures and underwater structures. It can provide a detailed description of the contours of underwater targets, enabling further tracking and identification.

[0003] Currently, 3D panoramic imaging sonars are typically installed on a tripod. Once mounted on a tripod, the height and angle of the sonar must be adjusted. Too high a height will increase the blind spot, too large an angle will cause interference, and too small an angle will easily cause instability. The combined mass of the 3D sonar and mounting platform is approximately 15 kg, far greater than the weight of the tripod. Therefore, the center of gravity is high during underwater operations, resulting in poor resistance to water currents and making the equipment prone to slipping, instability, or even being swept away.

[0004] The Chinese utility model patent number ZL202121544873.0 (authorization announcement number CN215728827U), "A bracket for enhancing the stability of three-dimensional sonar," discloses a bracket for sonar installation, which is a tripod bracket. The bracket includes a support rod, a leg tube, a base, a boom, a sonar fixing platform, and a connecting rod; three leg tubes are provided to form the three legs of the tripod bracket, and a base is provided at the bottom of each leg tube; three connecting rods are also provided, and the two ends of each connecting rod are connected to the middle of two adjacent leg tubes; the sonar fixing platform is set at the top of the leg tube and fixed to the leg tube, and one end of the boom is connected to the bottom of the sonar fixing seat; the support rod is set vertically downward and perpendicular to the sonar fixing platform, the top of the support rod is connected to the sonar fixing platform, and a counterweight is installed at the bottom of the support rod. Although this bracket can use the tripod and its added counterweight structure to lower the overall center of gravity of the equipment, increase the friction between the tripod and the bottom of the water, and be more stable during underwater operations, and less likely to slide, tilt, or fall over, because each leg of the tripod is fixed to the sonar fixing platform, and each connecting rod is also fixedly connected to the middle of two adjacent legs, the opening angle and arrangement height of the above-mentioned tripod are already fixed. Therefore, the tripod is not suitable for different three-dimensional panoramic imaging requirements. At the same time, the tripod is only suitable for flat placement. When the terrain slope of the bracket installation plane is large, the tripod is difficult to arrange stably. Therefore, further improvement of the existing technology is needed. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a sonar measurement system that can meet different three-dimensional imaging requirements while ensuring installation stability, in response to the above-mentioned existing technology.

[0006] The second technical problem to be solved by the present invention is to provide a three-dimensional imaging sonar underwater detection method using the above-mentioned sonar measurement system in response to the above-mentioned existing technology, which can be applied to three-dimensional imaging in terrain with a large slope ratio.

[0007] The third technical problem to be solved by the present invention is to provide a three-dimensional imaging sonar underwater detection method that can obtain a better field of view while ensuring that the sonar is firmly installed.

[0008] The technical solution adopted by the present invention to solve the first technical problem is: a sonar measurement system, including a sonar and a bracket; wherein the bracket includes:

[0009] Installation platform for sonar installation;

[0010] at least three support rods, each support rod having a first end capable of being restrained to the bottom of the mounting platform;

[0011] The number of connecting rods corresponds to the number of supporting rods, and each connecting rod connects two adjacent supporting rods;

[0012] The invention is characterized in that the first end of each support rod is constrained on the mounting platform in a manner that it can rotate relative to the mounting platform, and each connecting rod is constrained on the support rod in a manner that it can independently move up and down along the length direction of the support rod connected thereto.

[0013] In order to enhance the stability of the bracket, each support rod has a second end, and the second end of each support rod is rotatably connected to a base, and the bottom of the base is provided with a tip.

[0014] To achieve adjustment of the support rods and the connecting rods, preferably, the first end of each support rod is hinged to the mounting platform, and / or the connecting rod is hinged to the support rod, and / or the second end of each support rod is hinged to the base.

[0015] Preferably, there are three support rods.

[0016] The technical solution adopted by the present invention to solve the second technical problem is: a three-dimensional imaging sonar underwater detection method using the above-mentioned sonar measurement system, characterized by comprising the following steps:

[0017] Step 1: Obtain the slope of the underwater terrain;

[0018] Step 2: Based on the slope of the underwater terrain in step 1 and assuming boundary conditions according to the principle of the most unfavorable factor, perform mechanical analysis and stability calculation on the bracket;

[0019] Step 3: Based on the calculation results in step 2, lock the positions of the connecting rod and the support rod, assemble the mounting platform, then install the sonar on the mounting platform and connect the sonar to the remote control terminal;

[0020] Step 4: Place the sonar measurement system underwater until it reaches the slope of the underwater terrain. After the sonar measurement system is placed stably, start the sonar to perform underwater detection.

[0021] Furthermore, the slope of the underwater terrain is recorded as line GF, the horizontal plane of the underwater terrain is recorded as line GK, the intersection of the slope of the underwater terrain and the horizontal plane is point G, and a line DL perpendicular to line GK is drawn from the highest point D of the sonar. Point L is a point on line GK. The boundary conditions in step 2 are:

[0022] GL>0 and 0°<∠DGK<90°

[0023] Where GL is the distance between point G and point L, ∠DGK is the angle between line DG and line GK,

[0024] The line segment DH formed by point H and point D on the sonar installation platform is perpendicular to the straight line GF to obtain the line segment DO, where point O is the intersection of the line segment DH and the straight line GF. The slope α of the underwater terrain and the preset distance h between points H and O are substituted into the above boundary conditions to obtain the position of the support rod, and the position of the connecting rod is determined based on the position of the support rod.

[0025] To solve the third technical problem mentioned above, step 2 further includes calculating the maximum distance h between point H and point O. The specific process is as follows:

[0026] Set the preset distance h between point H and point O to [h min , h max ], where h min The distance at which the sonar fails to work properly; h max is the length of the support rod;

[0027] The h values are assigned in sequence using the binary method. The h values after assignment are recorded as: h1, h2, ...h j 、…h m ;

[0028] Among them, h1, h2, h j 、h mThese are the first assignment of h value, the second assignment of h value, the jth assignment of h value, and the mth assignment of h value, where m is the total number of assignments;

[0029] And calculate the boundary conditions in step 2 respectively with each h value after assignment until |h n -h (n-1) | less than qcm, h n Assign the value of h for the nth time, h (n-1) Assign the value of h for the n-1th time, n, n-1∈{1, 2…m}; q>0;

[0030] Then h n and h (n-1) The value that meets the boundary conditions is taken as the final h value, and the position of the support rod and the position of the support rod are determined according to the final h value.

[0031] Compared to existing technologies, the present invention offers advantages in that each support rod supporting the mounting platform is constrained to the mounting platform so that it can rotate relative to the platform, and each connecting rod connecting two adjacent support rods is constrained to the support rod so that it can independently move up and down along the length of the connected support rod. This allows for adjustable support angles, and by adjusting the position of the connecting rods, the support rod-formed bracket can be stably installed and adjusted to suit varying 3D imaging requirements, such as sloping terrain. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic structural diagram of a sonar measurement system according to an embodiment of the present invention;

[0033] Figure 2 for Figure 1 Another perspective structural diagram;

[0034] Figure 3 for Figure 1 Enlarged view of point A in the middle;

[0035] Figure 4 Schematic diagram of underwater terrain with slope in an embodiment of the present invention;

[0036] Figure 5 A simplified diagram of a sonar measurement system according to an embodiment of the present invention;

[0037] Figure 6 This is a simplified diagram of a sonar measurement system installed in a sloped underwater terrain in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0039] like Figures 1 to 3 As shown, the sonar measurement system in this embodiment includes a sonar 1 and a bracket 2. Measurements are performed by mounting the sonar 1 on the bracket 2. The specific structure of the sonar 1 can be referenced in the prior art and will not be described in detail here. The sonar 1 in this embodiment utilizes the 3D panoramic imaging sonar BV5000-1350. This 3D panoramic imaging sonar BV5000-1350 can directly acquire horizontal, vertical, and height data on the target's outline, while also obtaining detailed descriptions of the target's attributes, generating a real-time 3D stereo image of the target. Furthermore, the system is capable of operating in water environments with high sand content, low visibility, and complex underwater terrain.

[0040] like Figure 1 As shown, the bracket 2 includes a mounting platform 21, at least three support rods 22, a connecting rod 23, and a base 25. The mounting platform 21 in this embodiment is a circular flat-plate platform for mounting the sonar 1 on its upper surface; each support rod 22 has a first end 221 and a second end 222, the first end 221 of each support rod 22 is constrained to the bottom of the mounting platform 21, and the second end 222 of each support rod 22 is rotatably connected to the base 25, and the bottom of the base 25 is provided with a tip 251; Figure 2 As shown, the base 25 is disc-shaped. By inserting the tip 251 into the mud surface, the disc-shaped base 25 contacts the mud surface, thereby enhancing the lateral force stability of the bracket 2 and improving the applicability of the bracket 2 in complex terrain; the number of connecting rods 23 corresponds to the number of support rods 22, and each connecting rod 23 connects two adjacent support rods 22.

[0041] In this embodiment, the first end 221 of each support rod 22 is constrained on the mounting platform 21 in a manner that it can rotate relative to the mounting platform 21, and each connecting rod 23 is constrained on the support rod 22 in a manner that it can independently move up and down along the length direction of the support rod 22 connected thereto. Figure 3 As shown, each support rod 22 is respectively provided with a collar 24, and each connecting rod 23 is rotatably connected to the two adjacent collars 24. In this embodiment, the collar 24 is a circular movable buckle, which is convenient for disassembly and installation and is fixed by screws to enhance the flexibility of adjustment of the bracket 2. At both ends of the same connecting rod 23, one end is fixed to the collar 24 by a bolt, and the other end is fixed to the adjacent collar 24 by a movable pin.

[0042] In addition, in order to achieve adjustable length of the support rod 22, in this embodiment, there are three support rods 22, each of which includes at least two hollow rods that are mutually sleeved and can slide relatively telescopically, and the upper and lower adjacent rods are fixed by a connector 26. Figure 2 As shown, the connecting member 26 is a movable latch and a spring ejector pin.

[0043] In this embodiment, the first end 221 of each support rod 22 is hingedly connected to the mounting platform 21, the second end 222 of each support rod 22 is hingedly connected to the base 25, and the connecting rod 23 is hingedly connected to the collar 24. This hinged connection allows the angle between the support rod 22 and the mounting platform 21 to be flexibly changed. By adjusting the position of the collar 24 moving up and down along the length of the support rod 22, the position of the connecting rod 23 is adjusted to control the angle between the support rod 22 and the mounting platform 21.

[0044] like Figure 1 and Figure 2 As shown, three inverted U-shaped first mounting seats 30 are provided at the bottom of the mounting platform 21, one U-shaped second mounting seat 31 is provided on each base 25, and two lateral U-shaped third mounting seats 32 are provided on the side of each ring 24. The first end 221 and the second end 222 of each support rod 22 are respectively constrained in the first mounting seat 30 and the second mounting seat 31; the two ends of each connecting rod 23 are correspondingly constrained in the third mounting seats 32 on the two adjacent rings 24.

[0045] To achieve underwater detection of terrain with a large slope ratio, a three-dimensional imaging sonar underwater detection method using a sonar measurement system in this embodiment includes the following steps:

[0046] Step 1: Obtain the slope of the underwater terrain;

[0047] Step 2: Based on the slope of the underwater terrain in step 1 and assuming boundary conditions according to the principle of the most unfavorable factor, perform mechanical analysis and stability calculation on the bracket;

[0048] Step 3: Based on the calculation results in step 2, lock the positions of the connecting rod and the support rod, assemble the mounting platform, then install the sonar on the mounting platform and connect the sonar to the remote control terminal;

[0049] Step 4: Place the sonar measurement system underwater until it reaches the slope of the underwater terrain. After the sonar measurement system is placed stably, start the sonar to perform underwater detection.

[0050] In this embodiment, an attitude meter is used to measure the water depth of two points at a fixed distance along the slope direction in the working water area. Figure 4 As shown, the attitude meter is placed at two measuring points underwater along the slope at a fixed distance l. The slope tanα of the underwater terrain is calculated based on the two water depth differences h2-h1 and the fixed distance l, where tanα=(h2-h1) / l.

[0051] In order to carry out mechanical analysis and stability calculation of the bracket in step 2, the simplified diagram of the bracket is as follows Figure 5As shown, line segment DH represents the sonar, point H is the center point of the mounting platform 21, line segments HA, HJ, and HC are three support rods, each of which is of equal length; line segments MN, NP, and MP are three connecting rods. If the center of gravity of the sonar is always above the vertical projection area of the support leg ACJ, the bracket is in a stable and reliable state.

[0052] Assume that the points A, C, and J corresponding to the second ends of the three support rods are installed on the slope surface respectively, as shown in the following example: Figure 6 As shown, the triangle ACJ formed by points A, C, and J coincides with the slope surface. GK, KC, and HK are the x, y, and z axes respectively. Point F is the intersection of point H vertically downward and the slope surface. Point K is the intersection of point H vertically downward and the horizontal plane of the underwater terrain. Due to the inconsistent center of gravity and weight of the various structures of the bracket, the mass of the sonar above is relatively large. The sonar line segment DH is perpendicular to the slope surface GF and has a certain angle with the vertical line EH. Figure 6 It can be seen that the support rod and the sonar above it will tilt to a certain extent. Therefore, based on the most unfavorable working conditions and convenient calculation under large slope ratio terrain, when the line connecting the two legs AC is perpendicular to the slope line GF and ∠DGK is less than or equal to 90°, it can be guaranteed that the other arrangements of the bracket can be safe and stable under the same slope ratio terrain.

[0053] Draw line segment DH perpendicular to line GF, yielding line segment DO. Point O is the intersection of line segment DH and line GF. Because of the slope, sonar DH is perpendicular to the slope GF, forming ∠DHE = ∠FHO = ∠FGK = α with the vertical line. This creates a triangle HFO, HOJ, and HOC. The structural components show that the angles of rods AH, HJ, and HC on the sonar mounting platform can be adjusted, meaning that ∠JHO can be adjusted. Viewing the structure in the xy plane, the angle between the support rods is a constant 120°. The slope ∠FGK is α. Based on the mechanical analysis above, we know that ∠DGK < 90° is required to ensure support stability. Therefore, ∠HGF can be set to β.

[0054] The length of HO is initially set, that is, the vertical height from the mounting platform to the horizontal plane when the bracket is on the horizontal plane, and the rod length is constant at L;

[0055] HA=HC=HJ

[0056]

[0057] Because ∠JOC=120°

[0058]

[0059]

[0060]

[0061] OF=HOtanα

[0062]

[0063] GF=GO-OF

[0064] FK=GF·sin(α)

[0065] GK=GF·cos(α)

[0066] According to ∠DHE=∠FHO=∠FGK=α, the following quantitative relationship is obtained:

[0067] ED=DH·sin(α)

[0068] EH=DH·cos(α)

[0069] therefore

[0070] DL=EK=EH+HF+FK

[0071] GL=KG-ED

[0072] According to the boundary conditions:

[0073] GL>0 and 0°<∠DGK<90°

[0074] Where GL is the distance between point G and point L, ∠DGK is the angle between line DG and line GK,

[0075] Substituting the underwater terrain slope α and the preset distance h between points H and O into the above boundary conditions, the support rod positions are determined, and the connecting rod positions are determined based on the support rod positions. This ensures a stable and reliable support structure, capable of operating stably on steeply sloped terrain without changing the weight or structure of the equipment.

[0076] In order to obtain a better field of view, the distance h between point H and point O should be maximized as much as possible while ensuring the stability of the bracket during implementation. Therefore, step 2 also includes calculating the maximum value of the distance h between point H and point O. The specific process is:

[0077] Set the preset distance h between point H and point O to [h min , h max ], where h min The distance at which the sonar fails to work properly; h max is the length of the support rod;

[0078] The h values are assigned in sequence using the binary method. The h values after assignment are recorded as: h1, h2, ...h j 、…h m ;

[0079] Among them, h1, h2, h j 、h m These are the first assignment of h value, the second assignment of h value, the jth assignment of h value, and the mth assignment of h value, where m is the total number of assignments;

[0080] And calculate the boundary conditions in step 2 respectively with each h value after assignment until |h n -h (n-1) | less than qcm, h n Assign the value of h for the nth time, h (n-1) Assign the value of h for the n-1th time, n, n-1∈{1, 2…m}; q>0;

[0081] Then h n and h (n-1) The value that meets the boundary conditions is taken as the final h value, and the position of the support rod and the position of the support rod are determined according to the final h value.

[0082] In this embodiment, it is known that the support rod AH = 2m, the connecting rod MN = 1m, and the slope is 30°, h min = 10cm; Calculate the maximum distance h between points H and O. The steps are as follows:

[0083] 1) Slope = 30°, h max =2m, at this time ∠DGK is greater than 90°, which does not meet the design requirements;

[0084] 2) Slope = 30°, h min =10cm, then ∠DGK=58°50′28〃, which meets the design requirements;

[0085] 3) Based on the above calculation results, use the dichotomy method to calculate the slope = 30°, h = (L + 10) / 2;

[0086] 4) Repeat the above process until |h n -h (n-1) |Less than 2cm. Detailed calculation is shown in the following table.

[0087]

[0088] From the above table, we can see that |h8-h7|=0.016m=1.6cm, and ∠DGK=89°40′26″ is less than 90°, which meets the program requirements and the program ends.

[0089] From the table above, we can see that when calculating to h7, CJ = AC = 2.98m, and knowing AH = 2m, MN = 1m, according to the following formula:

[0090]

[0091] HM=0.67m is obtained, thus determining the position of the connecting rod.

Claims

1. A three-dimensional imaging sonar underwater detection method using a sonar measurement system, wherein the sonar measurement system comprises a sonar (1) and a bracket (2); wherein the bracket (2) comprises: A mounting platform (21) for mounting the sonar (1); Three support rods (22), each support rod (22) having a first end (221) capable of being constrained at the bottom of the mounting platform (21); and each support rod (22) having an equal length; The number of connecting rods (23) corresponds to the number of support rods (22), and each connecting rod (23) connects two adjacent support rods (22); The first end (221) of each support rod (22) is constrained on the mounting platform (21) in a manner that allows it to rotate relative to the mounting platform (21), and each connecting rod (23) is constrained on the support rod (22) in a manner that allows it to independently move up and down along the length direction of the support rod (22) to which it is connected; The three-dimensional imaging sonar underwater detection method is characterized by comprising the following steps: Step 1: Obtain the slope of the underwater terrain; Step 2: Based on the slope of the underwater terrain in step 1 and assuming boundary conditions according to the principle of the most unfavorable factor, perform mechanical analysis and stability calculation on the bracket; The slope of the underwater terrain is recorded as line GF, the horizontal plane of the underwater terrain is recorded as line GK, the intersection of the slope of the underwater terrain and the horizontal plane is point G, and a line DL perpendicular to line GK is drawn from the highest point D of the sonar. Point L is a point on line GK. The boundary conditions in step 2 are: GL>0 and 0°<∠DGK<90° Where GL is the distance between point G and point L, ∠DGK is the angle between line DG and line GK, Points H and D on the sonar installation platform form a line segment DH. Line segment DH is perpendicular to line GF to obtain line segment DO, where point O is the intersection of line segment DH and line GF. Substituting the slope α of the underwater terrain and the preset distance h between points H and O into the above boundary conditions, the position of the support rod can be obtained, and the position of the connecting rod can be determined based on the position of the support rod. Step 3: Based on the calculation results in step 2, lock the positions of the connecting rod and the support rod, assemble the mounting platform, then install the sonar on the mounting platform and connect the sonar to the remote control terminal; Step 4: Place the sonar measurement system underwater until it reaches the slope of the underwater terrain. After the sonar measurement system is placed stably, start the sonar to perform underwater detection.

2. The three-dimensional imaging sonar underwater detection method according to claim 1, characterized in that: Each support rod (22) has a second end (222), and the second end (222) of each support rod (221) is also rotatably connected to a base (25), and a tip (251) is provided at the bottom of the base (25).

3. The three-dimensional imaging sonar underwater detection method according to claim 2, characterized in that: The first end (221) of each support rod (22) is hinged to the mounting platform (21), and / or the connecting rod (23) is hinged to the support rod (22), and / or the second end (222) of each support rod (22) is hinged to the base (25).

4. The three-dimensional imaging sonar underwater detection method according to claim 1, characterized in that: The step 2 also includes calculating the maximum distance h between point H and point O. The specific process is: Set the preset distance h between point H and point O to [h min , h max ], where h min The distance at which the sonar fails to work properly; h max is the length of the support rod; The h values are assigned in sequence using the binary method. The h values after assignment are recorded as: h1, h2, ...h j 、…h m ; Among them, h1, h2, h j 、h m These are the first assignment of h value, the second assignment of h value, the jth assignment of h value, and the mth assignment of h value, where m is the total number of assignments; And calculate the boundary conditions in step 2 respectively with each h value after assignment until |h n -h (n-1) | less than qcm, h n Assign the value of h for the nth time, h (n-1) Assign the value of h for the n-1th time, n, n-1∈{1, 2…m}; q>0; Then h n and h (n-1) The value that meets the boundary conditions is taken as the final h value, and the position of the support rod and the position of the connecting rod are determined according to the final h value.

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