Unmanned surface vehicle for three-dimensional sonar survey of bridge scour and underwater defects, and measurement method thereof

Abstract

An unmanned surface vehicle for three-dimensional sonar survey of bridge scour and underwater defects, and a measurement method thereof. The unmanned surface vehicle comprises a vehicle body and a sonar provided on the vehicle body, and further comprises a control assembly mounted on the central axis of the bottom of the vehicle body, a gyroscope locked in a preset scanning direction of the sonar, an inertial navigation system used for recording vehicle motion data of the vehicle body, and a controller. The control assembly comprises a first gimbal for controlling the sonar to rotate in a vehicle motion direction, a second gimbal for controlling the sonar to rotate in a direction perpendicular to the vehicle motion direction, and a third gimbal for controlling the sonar to rotate in a direction perpendicular to a plane formed by rotation directions of the first gimbal and the second gimbal. The sonar is controlled by means of the control assembly, so that the survey operation attitude of the solar is more flexible. In addition, the gyroscope and the inertial navigation system are used as the basis for controlling the attitude of the sonar, which is beneficial to adjusting the sonar to be always in the preset scanning direction, thereby achieving comprehensive scanning.

Description

An unmanned surface vessel and its measurement method for three-dimensional sonar scanning of bridge scour and underwater defects. Technical Field

[0001] This invention relates to a three-dimensional sonar measurement device and method, and more particularly to an unmanned vessel for three-dimensional sonar scanning of bridge scour and underwater defects and its measurement method. Background Technology

[0002] Bridges are vital infrastructure, serving as crucial transportation links for roads and railways. Due to the long-term impact of water flow and other environmental factors, the underwater sections of bridges are prone to various defects, such as concrete cracking and steel reinforcement corrosion. These defects not only affect the structural safety of the bridge but may also lead to damage or even loss of its function, posing serious safety hazards to transportation. Furthermore, the underwater sections of bridges are susceptible to erosion. Erosion can cause surface deformation, erosion, and even localized damage to components such as piers and foundations, thereby affecting the stability and service life of the bridge. Therefore, timely detection and monitoring of underwater defects and erosion are essential for ensuring the safe operation of bridges.

[0003] In existing technologies, sonar is mostly used to monitor the damage to bridges caused by water erosion and underwater defects. Sonar emits sound waves and receives their echo signals. By utilizing the speed of sound propagation in the medium and the time difference of the echo signal, the target distance is calculated. By controlling the emission angle and reception direction of the sound waves, the horizontal azimuth and elevation angles of the target are determined, thereby achieving the positioning and imaging of the target in three-dimensional space. However, most existing sonars are fixedly installed on the hull of a survey vessel. The survey vessel moves along a certain lateral line to monitor underwater defects and erosion. Because the sonar is in a fixed position, its rotation and movement can only be indirectly controlled by controlling the operation of the survey vessel. Due to the large size of the survey vessel and the influence of specific environmental factors during operation, the rotation and movement of the sonar are limited, making it impossible to achieve comprehensive coverage of the underwater structure of the bridge and the eroded terrain. Furthermore, the operation is cumbersome and the measurement cost is high. Summary of the Invention

[0004] Purpose of the invention: The first purpose of this invention is to provide an unmanned surface vessel capable of providing comprehensive coverage of the underwater structure of bridges and scour terrain for three-dimensional sonar scanning of bridge scour and underwater defects.

[0005] The second objective of this invention is to provide a measurement method for an unmanned vessel used for three-dimensional sonar scanning of bridge scour and underwater defects.

[0006] Technical Solution: The present invention discloses an unmanned surface vessel (USV) for three-dimensional sonar scanning of bridge scour and underwater defects, comprising a hull and a sonar mounted on the hull, a control component mounted on the central axis of the bottom of the hull for connecting and adjusting the sonar scanning direction, a gyroscope locked in the preset scanning direction of the sonar and installed inside the hull cabin, an inertial navigation system for recording the hull's travel data, and a controller based on the data adjustment control component of the gyroscope and the inertial navigation system. The control component includes a first gimbal for controlling the rotation of the sonar in the direction of travel, a second gimbal for controlling the rotation of the sonar perpendicular to the direction of travel, and a third gimbal for controlling the rotation of the sonar in a direction perpendicular to the plane formed by the rotation directions of the first and second gimbals.

[0007] Furthermore, it also includes stabilizing components symmetrically arranged on both sides of the hull. The stabilizing components include two symmetrically mounted directional hinge supports on the hull side, anti-roll fins connected to the hull via the directional hinge supports, bilge keels fixedly mounted on the bilges, two quick-release supports arranged between the two directional hinge supports and connected to the hull, connecting rods connected to the quick-release supports, and side plates fixedly connected to the other end of the two connecting rods.

[0008] Furthermore, the connecting rod is configured as a telescopic rod, and the telescopic rod is electrically connected to the controller.

[0009] Furthermore, the top of the sonar is equipped with a base that is inserted into the control component. Both the base and the control component have pin holes. A positioning pin is installed on one side of the base by a spring, and the positioning pin is inserted into the base and the control component through the pin hole.

[0010] Furthermore, it also includes a powered propeller installed at the stern of the hull, and the powered propeller is electrically connected to the controller.

[0011] Based on the same inventive concept, the present invention also provides a measurement method for an unmanned vessel used for three-dimensional sonar scanning of bridge scour and underwater defects, comprising the following steps:

[0012] S1: Before the ship starts, the scanning direction of the sonar is set, and then the gyroscope is activated and locked in the same attitude as the scanning direction of the sonar. The gyroscope records the scanning direction data and transmits it to the controller.

[0013] S2: After the ship starts, the inertial navigation system acquires the ship's movement data in real time and transmits it to the controller;

[0014] S3: Calculate the control deviation between the current scanning direction of the sonar and the set scanning direction based on the scanning direction data and ship movement data;

[0015] S4: Calculate the gimbal control quantity of the control component to rotate the sonar based on the control deviation;

[0016] S5: Convert the gimbal control input to obtain the rotation angle corresponding to the control component;

[0017] S6: The controller adjusts the rotation of the control components in real time according to the rotation angle, so that the sonar always maintains the set scanning direction. The controller controls the rotation of the gyroscope and locks it in the attitude after the sonar rotates.

[0018] S7: Repeat steps S2 to S6 until the scan is complete.

[0019] Furthermore, the scanning direction data includes the roll direction angle α(t), pitch direction angle β(t), and yaw direction angle γ(t) of the gyroscope in the ship's center of mass coordinate system at this time.

[0020] Furthermore, the ship's navigation data includes the ship's current roll direction and angle α. s (t), pitch direction rotation angle β s (t) and yaw direction angle γ1(t).

[0021] Furthermore, the formula for calculating the control deviation is as follows:

[0022] The formula for calculating the PTZ control parameters is as follows:

[0023] Where K p The ratio value in the proportional calculation, T i The time constant for integral calculation, T d The time constant for differential calculations.

[0024] Furthermore, the method for converting and processing the gimbal control input to obtain the corresponding rotation angle of the control component is as follows:

[0025] Error control is adopted for each sampling point, and differential processing is performed based on the first-order backward difference method. The differential calculation formula for the control deviation is as follows:

[0026] In the formula, k represents the sampling time, T is the sampling period, and θ(k) and θ(k-1) are the error signals between the k-th sampling time and the (k-1)-th sampling time.

[0027] The cumulative operation is used instead of the integral operation, and the calculation formula is as follows:

[0028] Using sampling point KT instead of continuous time t, the calculation formula is as follows: t=KT(k=0,1,2,...);

[0029] The sonar directional digital PID is obtained by summarizing the results. The angle of rotation of the gimbal is adjusted according to the calculated action. The calculation expression is as follows:

[0030] Where k i =k p / T,k d =k d T d .

[0031] Beneficial Effects: Compared with the prior art, the present invention has the following significant advantages: The present invention regulates the underwater operating attitude of the sonar through control components, making the sonar scanning operation more flexible. Simultaneously, the use of a gyroscope and inertial navigation system as the basis for regulating the sonar attitude facilitates adjusting the sonar attitude to ensure it remains in the preset scanning direction, enabling comprehensive coverage of underwater bridge structures and eroded terrain. This improves the accuracy and stability of the sonar during large-angle underwater scanning. The stabilizing components reduce the sway of the vessel, improving its stability during underwater navigation. The positioning pins facilitate the installation and disassembly of the sonar, reducing cumbersome steps in the installation process, simplifying sonar scanning operations, and improving operational efficiency. Attached Figure Description

[0032] Figure 1 is a top view of the hull of the device of the present invention;

[0033] Figure 2 is a left view of the hull of the device of the present invention;

[0034] Figure 3 is a cross-sectional view of the hull of the device of the present invention;

[0035] Figure 4 is a schematic diagram of the hull control assembly of the device of the present invention;

[0036] Figure 5 is a schematic diagram of the quick-release support of the device of the present invention;

[0037] Figure 6 is a front view of the base and sonar of the device of the present invention;

[0038] Figure 7 is a cross-sectional view of the positioning pin of the device of the present invention;

[0039] Figure 8 is a flowchart of the method of the present invention. Detailed Implementation

[0040] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0041] Example 1

[0042] The present invention discloses an unmanned surface vessel (USV) for three-dimensional sonar scanning of bridge scour and underwater defects, as shown in Figures 1-3. It includes a hull 1, a sonar 2, a control assembly 3, a gyroscope 4, an inertial navigation system 5, a controller 6, a stabilization assembly 10, and a propeller 19. The control assembly 3 is mounted on the central axis of the bottom of the hull 1. The gyroscope 4 is installed inside the cabin of the hull 1, as shown in Figures 6 and 7. A base 17 is mounted on the top of the sonar 2, which is inserted into the control assembly 3. Both the base 17 and the control assembly 3 have pin holes. A positioning pin 18 is spring-loaded on one side of the base 17, and the positioning pin 18 is inserted into the base 17 and the control assembly 3 through the pin holes. That is, the sonar 2 is detachably connected to the control assembly 3 via the positioning pin 18. The control assembly 3 includes a first gimbal 7 for controlling the rotation of the sonar 2 in the direction of travel, a second gimbal 8 for controlling the rotation of the sonar 2 perpendicular to the direction of travel, and... As shown in Figure 1, a third gimbal 9 controls the rotation of sonar 2 in a direction perpendicular to the plane formed by the rotation directions of the first gimbal 7 and the second gimbal 8. As shown in Figure 2, the first gimbal 7 rotates around the x-axis, the second gimbal 8 rotates around the y-axis, and the third gimbal rotates around the z-axis. As shown in Figure 4, the control component 3 and sonar 2 are electrically connected to the controller 6. Preferably, a connecting pipe is installed at the bottom of the hull 1, and cable channels are reserved at the bottom of the hull 1 and inside the connecting pipe. A dedicated communication cable for information communication between sonar 2 and control component 3 passes through the cable channel and connects to the controller 6. Preferably, the controller 6 is an industrial-grade portable computer, and a mobile power supply 21 for power supply is installed inside the cabin of the hull 1. The controller 6 adjusts the scanning direction of sonar 2 by adjusting the rotation of the first gimbal 7, the second gimbal 8, and the third gimbal 9 of the control component 3. Before the ship 1 starts, the gyroscope 4 is locked in an attitude consistent with the initially set scanning direction of the sonar 2. During the movement of the ship 1, the gyroscope 4 is not affected by the direction or angle of the ship 1's movement and is always locked in the initially set scanning direction of the sonar 2. The inertial navigation system 5 is used to record the ship 1's movement data. The controller 6 uses a PID control algorithm to correct the real-time scanning direction of the sonar 2 based on the real-time movement data obtained by the inertial navigation system 5 and the locked attitude of the gyroscope 4, so that the scanning direction of the sonar 2 is maintained in a fixed direction.Furthermore, the antenna 20 of the inertial navigation system 5 is bolted to the deck of the hull 1, and a pipe for connecting the inertial navigation system 5 and the antenna 20 is reserved inside the hull 1. A dedicated communication cable for connecting the two is installed in the pipe. The controller 6 adjusts the control component 3 based on the attitude of the gyroscope 4 and the real-time ship movement data of the hull 1 obtained by the inertial navigation system 5, so that the control component 3 adjusts the scanning direction of the sonar 2 in real time, thereby ensuring that the scanning direction of the sonar 2 is always consistent with the initially set scanning direction. There are two sets of stabilization components 10, which are symmetrically installed on both sides of the hull 1 to improve the stability of the hull 1 when it is moving. The power propeller 19 is installed at the stern of the hull 1 and is electrically connected to the controller 6. The controller 6 can adjust the power propeller 19 to drive the hull 1.

[0043] As shown in Figures 1, 2, and 5, the stabilizing assembly 10 includes a directional hinge support 11, a roll damper 12, a bilge keel 13, a quick-release support 14, a connecting rod 15, and a side plate 16. A set of stabilizing assemblies 10 has two directional hinge supports 11, which are symmetrically mounted on the ship's side. The roll damper 12 is connected to the hull 1 via the directional hinge supports 11. The roll damper 12 and the directional hinge supports 11 are used to reduce the sway of the hull 1. The bilge keel 13 is fixedly mounted on the bilge and is used to lift the hull. The stability of hull 1 during navigation is improved by a set of stabilizing components 10, which includes two quick-release supports 14 symmetrically mounted on the hull 1 between two directional hinge supports 11. Each quick-release support 14 is connected to a connecting rod 15 at its other end. A side panel 16 is fixedly connected to the end of each connecting rod 15 furthest from the hull 1. The quick-release supports 14, connecting rods 15, and side panel 16 allow the hull 1 structure to be converted into a multihull, improving its stability and seakeeping. Preferably, the connecting rod 15 is a telescopic rod electrically connected to the controller 6. The connecting rod 15 is inclined, and its telescopic nature allows adjustment of the height and position of the side panel 16, changing the center of gravity and increasing the moment of inertia, thus enhancing the seakeeping of the hull 1. The quick-release supports 14 enable rapid installation and removal of the connecting rods 15, facilitating subsequent maintenance of the connecting rods 15 and the side panel 16.

[0044] Example 2

[0045] The measurement method of an unmanned surface vessel for three-dimensional sonar scanning of bridge scour and underwater defects, as described in this invention, includes the following steps, as shown in Figure 8:

[0046] S1: Before the hull 1 is started, the scanning direction of the sonar 2 is set, and then the gyroscope 4 is started and locked in the same attitude as the scanning direction of the sonar 2. The scanning direction data on the gyroscope 4 is transmitted to the controller 6. The scanning direction data includes the roll direction angle α(t), pitch direction angle β(t), and yaw direction angle γ(t) of the gyroscope 4 in the center-of-mass coordinate system of the hull 1 at this time.

[0047] S2: After the ship 1 starts, the inertial navigation system 5 acquires the ship's movement data of the ship 1 in real time and transmits it to the controller 6; the movement data includes the roll direction and angle α of the ship 1 at the current moment. s (t), pitch direction rotation angle β s (t) and yaw direction angle γ1(t).

[0048] S3: Calculate the control deviation between the current scanning direction and the set scanning direction of sonar 2 based on the scanning direction data and ship movement data; and the formula for calculating the control deviation is as follows:

[0049] S4: Calculate the gimbal control quantity for rotating sonar 2 using control component 3 based on the control deviation; the calculation formula for the gimbal control quantity is as follows:

[0050] Where K p The ratio value in the proportional calculation, T i The time constant for integral calculation, T d The time constant for differential calculations.

[0051] The calculated θ(t) is then used for proportional, integral, and differential calculations of the deviation. First, the proportional calculation is performed: if the control direction of sonar 2 deviates, the gimbal will immediately adjust the direction of sonar 2, and the adjustment force will vary with the proportional value K. p The first step is to increase the time constant T, thereby adaptively reducing the system's deviation and ensuring that sonar 2 does not become unstable due to steady-state error. The second step is integral calculation, which is used to adjust the system's stability and the positive and negative accuracy of the control. The adjustment force of the integral calculation is determined by the time constant T. i The larger this value, the smaller its impact on system adjustment; finally, differential calculation is used to adjust the deviation signal, adjusting the differential output of the error θ(t), ensuring the effectiveness of signal control when the error changes abruptly, and ensuring early and effective signal correction. Its control strength is determined by the time constant T of the differential action. d Decide.

[0052] S5: The gimbal control input is converted to obtain the rotation angle corresponding to control component 3. Error control is applied to each sampling point, and differential processing is performed based on the first-order backward difference method. The differential calculation formula for the control deviation is as follows:

[0053] In the formula, k represents the sampling time, T is the sampling period, and θ(k) and θ(k-1) are the error signals between the k-th sampling time and the (k-1)-th sampling time.

[0054] The cumulative operation is used instead of the integral operation, and the calculation formula is as follows:

[0055] Using sampling point KT instead of continuous time t, the calculation formula is as follows: t=KT(k=0,1,2,...);

[0056] The sonar-2 directional digital PID controller is obtained by summarizing the results. The angle of rotation of the gimbal is adjusted according to the calculated action value. The calculation expression is as follows:

[0057] Where k i =k p / T,k d =k d T d .

[0058] S6: The controller 6 adjusts the rotation of the control component 3 in real time according to the rotation angle, so that the sonar 2 always maintains the set scanning direction. The controller 6 controls the rotation of the gyroscope 4 and locks it in the attitude after the sonar 2 rotates.

[0059] S7: Repeat steps S2 to S6 until the scan is complete.

Claims

1. An unmanned surface vessel (USV) for three-dimensional sonar scanning of bridge scour and underwater defects, comprising a hull (1) and a sonar (2) mounted on the hull (1), characterized in that: It also includes a control component (3) installed on the central axis at the bottom of the hull (1) for connecting and adjusting the scanning direction of the sonar (2), a gyroscope (4) locked in the preset scanning direction of the sonar (2) and installed inside the cabin of the hull (1), an inertial navigation system (5) for recording the ship's (1) travel data, and a controller (6) based on the data adjustment control component (3) of the gyroscope (4) and the inertial navigation system (5). The control component (3) includes a first gimbal (7) for controlling the rotation of the sonar (2) in the ship's travel direction, a second gimbal (8) for controlling the rotation of the sonar (2) perpendicular to the ship's travel direction, and a third gimbal (9) for controlling the rotation of the sonar (2) in a direction perpendicular to the plane formed by the rotation directions of the first gimbal (7) and the second gimbal (8).

2. The unmanned surface vessel for three-dimensional sonar scanning of bridge scour and underwater defects according to claim 1, characterized in that: It also includes stabilizing components (10) symmetrically arranged on both sides of the hull (1). The stabilizing components (10) include two directional hinge supports (11) symmetrically installed on the hull side, anti-roll fins (12) connected to the hull (1) through the directional hinge supports (11), bilge keels (13) fixedly installed on the bilge, two quick-release supports (14) arranged between the two directional hinge supports (11) and connected to the hull (1), connecting rods (15) connected to the quick-release supports (14), and side plates (16) fixedly connected to the other end of the two connecting rods (15).

3. The unmanned surface vessel for three-dimensional sonar scanning of bridge scour and underwater defects according to claim 2, characterized in that: The connecting rod (15) is configured as a telescopic rod, and the telescopic rod is electrically connected to the controller (6).

4. The unmanned surface vessel for three-dimensional sonar scanning of bridge scour and underwater defects according to claim 1, characterized in that: The top of the sonar (2) is equipped with a base (17) that is inserted into the control component (3). Both the base (17) and the control component (3) have pin holes. A positioning pin (18) is installed on one side of the base (17) by a spring, and the positioning pin (18) is inserted into the base (17) and the control component (3) through the pin hole.

5. The unmanned surface vessel for three-dimensional sonar scanning of bridge scour and underwater defects according to claim 1, characterized in that: It also includes a power propeller (19) installed at the stern of the hull (1), and the power propeller (19) is electrically connected to the controller (6).

6. A measurement method for an unmanned surface vessel (USV) used for three-dimensional sonar scanning of bridge scour and underwater defects according to any one of claims 1 to 5, characterized in that: Includes the following steps: S1: Before the hull (1) is started, the scanning direction of the sonar (2) is set, and then the gyroscope (4) is started and locked in the same attitude as the scanning direction of the sonar (2). The gyroscope (4) records the scanning direction data and transmits it to the controller (6). S2: After the hull (1) is started, the inertial navigation system (5) acquires the ship's (1) navigation data in real time and transmits it to the controller (6); S3: Calculate the control deviation between the current scanning direction and the set scanning direction of the sonar (2) based on the scanning direction data and the ship's movement data; S4: Calculate the gimbal control quantity of the control component (3) rotating the sonar (2) based on the control deviation; S5: Convert the gimbal control input to obtain the rotation angle corresponding to the control component (3); S6: The controller (6) adjusts the rotation of the control component (3) in real time according to the rotation angle so that the sonar (2) always maintains the set scanning direction. The controller (6) controls the gyroscope (4) to rotate and lock it in the attitude after the sonar (2) rotates. S7: Repeat steps S2 to S6 until the scan is complete.

7. The measurement method for an unmanned surface vessel used for three-dimensional sonar scanning of bridge scour and underwater defects according to claim 6, characterized in that: The scanning direction data includes the roll direction angle α(t), pitch direction angle β(t), and yaw direction angle γ(t) of the gyroscope (4) in the center-of-mass coordinate system of the hull (1) at this time.

8. The measurement method for an unmanned surface vessel used for three-dimensional sonar scanning of bridge scour and underwater defects according to claim 7, characterized in that: The ship's navigation data includes the ship's (1) current roll direction and angle α. s (t), pitch direction rotation angle β s (t) and yaw direction angle γ1(t).

9. The measurement method for an unmanned surface vessel used for three-dimensional sonar scanning of bridge scour and underwater defects according to claim 8, characterized in that: The formula for calculating the control deviation is as follows: The formula for calculating the PTZ control parameters is as follows: Where K p The ratio value in the proportional calculation, T i The time constant for integral calculation, T d The time constant for differential calculations.

10. The measurement method for an unmanned surface vessel used for three-dimensional sonar scanning of bridge scour and underwater defects according to claim 9, characterized in that: The method for converting and processing the gimbal control input to obtain the rotation angle corresponding to the control component (3) is as follows: Error control is adopted for each sampling point, and differential processing is performed based on the first-order backward difference method. The differential calculation formula for the control deviation is as follows: In the formula, k represents the sampling time, T is the sampling period, and θ(k) and θ(k-1) are the error signals between the k-th sampling time and the (k-1)-th sampling time. The cumulative operation is used instead of the integral operation, and the calculation formula is as follows: Using sampling point KT instead of continuous time t, the calculation formula is as follows: t = KT (k = 0, 1, 2, ...); The sonar (2) directional digital PID is obtained by summarizing the results. The angle of rotation of the gimbal is adjusted according to the calculated action. The calculation expression is as follows: Where k i =k p / T,k d =k d T d .

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