An underwater robot positioning and navigation method in a zigzag-shaped tunnel and an underwater robot

Abstract

The application discloses a kind of underwater robot positioning navigation method and underwater robot in broken line shape tunnel, belong to underwater robot field.The technical scheme thereof includes according to the first single-beam range finder measurement parameter and tunnel structure parameter determines the first position information of robot in first position in tunnel;First position information is used to represent the relative position information between underwater robot and the start point and / or end point of tunnel;According to the second single-beam range finder measurement parameter determines the second position information in first position, and second position information is used to represent the relative position information between underwater robot and tunnel wall in tunnel;Determine the motion control instruction of underwater robot based on first position information and the second position information;Motion control instruction is used to control the motion of underwater robot in tunnel.The application is applied to broken line shape underwater tunnel aspect, high accuracy, simple operation, strong applicability.

Description

Technical Field

[0001] This invention belongs to the field of underwater robots, and particularly relates to an underwater robot positioning and navigation method and an underwater robot in a zigzag tunnel. Background Technology

[0002] In the inspection of long-distance water conveyance tunnels (without emptying the water) using remotely operated vehicles (ROVs), the accurate location information of the ROVs is the foundation of the entire operation.

[0003] Due to the weak underwater satellite signal, especially in long, zigzag-shaped underwater tunnels where interference is more severe, existing underwater navigation and positioning technologies primarily rely on inertial navigation devices for remotely operated vehicles (ROVs). However, these devices all have measurement errors, which increase with longer operating times. In the inspection of long water conveyance tunnels, the cumulative positional error generated by this approach is unacceptable.

[0004] Meanwhile, some solutions involve deploying positioning markers inside the tunnel, such as spraying coordinates on the tunnel walls or installing RFID cards inside the tunnel. These methods require extensive modifications to the water conveyance tunnel, and the deployed markers are easily covered by dirt, making subsequent maintenance work quite arduous.

[0005] Currently, there is still a lack of a highly accurate, simple to operate, and widely applicable method for underwater robot positioning and navigation in polygonal tunnels. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is that there is still a lack of an underwater robot positioning and navigation method in a polygonal tunnel that is highly accurate, simple to operate and widely applicable. The present invention proposes an underwater robot positioning and navigation method in a polygonal tunnel that is highly accurate, simple to operate and widely applicable.

[0007] To solve the aforementioned technical problem, the technical solution adopted by the present invention is as follows: A method for positioning and navigation of an underwater robot in a polygonal tunnel includes: determining first position information of the robot at a first position in the tunnel based on measurement parameters of a first single-beam rangefinder and tunnel structural parameters; the measurement parameters of the first single-beam rangefinder are used to characterize the actual position of the underwater robot in a first direction; the first position information is used to characterize the relative position information between the underwater robot and the starting point and / or ending point of the tunnel. The second position information at the first position is determined based on the measurement parameters of the second single-beam rangefinder. The second position information is used to characterize the relative position information of the underwater robot between the tunnel wall and the tunnel. The measurement parameters of the second single-beam rangefinder are used to characterize the actual position of the underwater robot in the second direction plane. Motion control commands for the underwater robot are determined based on the first position information and the second position information; the motion control commands are used to control the movement of the underwater robot in the tunnel.

[0008] In some embodiments, when the error between the actual measured value and the tunnel structural parameters matches a preset error range, the underwater robot is controlled to move in the tunnel; when the error does not match the error range, the first single-beam ranging parameter and the second single-beam ranging parameter are corrected according to the error.

[0009] In some embodiments, the method further includes establishing a coordinate system, which includes: an origin and X-axis, Y-axis, and Z-axis derived from the origin; the geometric center point or motion control core point of the underwater robot is selected as the origin of the coordinate system, and the origin is bound to the motion state of the underwater robot in real time; X-axis: set along the tangent direction of the tunnel's central axis, and the positive direction of the X-axis is consistent with the preset travel direction of the underwater robot; when the tunnel turns left or right, the X-axis direction deflects synchronously with the tangent of the tunnel's central axis; when the tunnel rises or falls, the X-axis direction tilts synchronously with the slope of the tunnel's central axis; Y-axis: perpendicular to the X-axis and located within the horizontal cross-section of the tunnel, with the positive direction of the Y-axis pointing towards the left side wall of the tunnel, used to characterize the underwater robot's offset relative to the tunnel's central axis in the left-right direction; Z-axis: perpendicular to the tunnel cross-section formed by the X-axis and Y-axis, with the positive direction of the Z-axis pointing vertically downwards, used to characterize the underwater robot's offset relative to the tunnel's central axis in the up-down direction.

[0010] In some embodiments, determining the first position information of the underwater robot at a first position in the tunnel based on the measurement parameters of the first single-beam rangefinder and the tunnel structure parameters includes: transmitting ranging signals to the positive X-axis direction and the negative X-axis direction respectively using the first single-beam rangefinder, receiving the reflected signals and calculating the propagation time; determining the straight-line distance between the underwater robot and the tunnel inflection point in the positive X-axis direction and the straight-line distance between the underwater robot and the tunnel inflection point in the negative X-axis direction based on the signal propagation speed and propagation time; matching the distance information with the axial distances from the starting point to each feature point and the ending point preset in the tunnel structure parameters to determine the mileage interval in which the underwater robot is located, as the first position information, used to characterize the progressive position of the underwater robot relative to the starting point / ending point in the tunnel axial direction.

[0011] In some embodiments, determining the second position information of the underwater robot at the first position in the tunnel based on the measurement parameters of the second single-beam rangefinder includes: transmitting ranging signals in the positive Y-axis direction and the positive Z-axis direction respectively using the second single-beam rangefinder, receiving reflected signals in each direction and calculating the propagation time; determining the distance between the underwater robot and the left side wall of the tunnel and the distance between the underwater robot and the bottom wall of the tunnel based on the signal propagation speed and propagation time; calculating the lateral and vertical offsets of the underwater robot relative to the central axis of the tunnel based on the horizontal and vertical cross-sectional dimensions of the tunnel and the distances in each direction, and using the lateral and vertical offsets as the second position information to characterize the spatial position of the underwater robot relative to the central axis within the cross-section of the tunnel.

[0012] In some embodiments, controlling the movement of an underwater robot in a tunnel based on first and second position information includes: determining the current mileage position of the underwater robot along the tunnel axis based on the first position information, and planning the target travel path and speed parameters of the underwater robot in the X-axis direction by combining the axial orientation corresponding to the mileage interval in the tunnel structural parameters; calculating the deviation value of the current position relative to the tunnel center axis based on the lateral and vertical offsets in the second position information, and generating a lateral correction command in the Y-axis direction and a vertical leveling command in the Z-axis direction when the deviation value exceeds a preset safety threshold; and fusing the travel control command in the X-axis direction with the deviation correction commands in the Y and Z-axis directions to drive the underwater robot's propulsion system to work together, so that the robot can maintain its movement along the tunnel axis while maintaining a preset offset range relative to the center axis, thereby achieving autonomous navigation within the polygonal tunnel.

[0013] In some embodiments, the positioning and navigation method further includes: when the underwater robot is in a horizontal straight section or a horizontal turning section within the tunnel, acquiring the underwater robot's current actual heading angle in real time using an electronic compass; retrieving the preset heading angle of the tunnel's central axis corresponding to the horizontal section from the tunnel's structural parameters; comparing the actual heading angle with the preset heading angle to calculate the heading deviation value; generating a direction correction command based on the heading deviation value to drive the underwater robot's lateral propulsion system to adjust its movement direction, ensuring that while the underwater robot is moving along the tunnel axis, its offset relative to the tunnel's central axis is always maintained within a preset safe offset range.

[0014] In some embodiments, the positioning and navigation method further includes: when the underwater robot is in a horizontal straight section or a horizontal turning section within the tunnel, measuring the vertical distance between the underwater robot and the water surface using a depth sounder, comparing and calibrating the measured value with the vertical offset in the second position information, and correcting the position parameter in the Z-axis direction to improve the accuracy of the second position information; when the underwater robot is in a vertically ascending and descending section within the tunnel, measuring the vertical distance between the underwater robot and the water surface using a depth sounder, comparing and calibrating the measured value with the axial mileage parameter in the first position information, and correcting the position parameter in the X-axis direction to improve the accuracy of the first position information.

[0015] This invention also discloses an underwater robot suitable for polygonal underwater tunnels, comprising: Motion control unit, first single-beam rangefinder, second single-beam rangefinder, and propulsion system; The first single-beam rangefinder is used to acquire the first single-beam rangefinder measurement parameters of the underwater robot; the first single-beam rangefinder measurement parameters are used to characterize the actual position of the underwater robot in the first direction. The second single-beam rangefinder is used to acquire the measurement parameters of the underwater robot; the measurement parameters of the second single-beam rangefinder are used to characterize the actual position of the underwater robot in the second direction plane; the second direction plane is not parallel to the first direction; The motion control system is used to determine the first position information of the underwater robot in the tunnel at a first position based on the measurement parameters of the first single-beam rangefinder and the structural parameters of the tunnel structure, and to determine the second position information of the underwater robot in the first position based on the measurement parameters of the second single-beam rangefinder, and to determine the motion control command for the underwater robot based on the first position information and the second position information. The propulsion system is used to control the movement of the underwater robot in the tunnel according to motion control commands.

[0016] In some embodiments, the underwater robot includes: a robot body, a first single-beam rangefinder, a second single-beam rangefinder, an electronic compass, a depth sounder, a propulsion system, and a storage module; The robot body has a built-in motion control unit for executing the above-mentioned underwater robot positioning and navigation method applicable to polygonal underwater tunnels; The first single-beam rangefinder is installed at the ends of the robot body along the positive and negative X-axis directions. It is used to transmit ranging signals in the direction of the tunnel axis and receive reflected signals to obtain the distance information between the underwater robot and the turning point of the tunnel. The second single-beam rangefinder is installed at the positive Y-axis end and the positive Z-axis end of the robot body. It is used to transmit ranging signals to the left side wall and bottom wall of the tunnel and receive reflected signals to obtain the lateral and vertical distance information between the underwater robot and the tunnel wall. An electronic compass is mounted on the top of the robot body to collect the actual heading angle of the underwater robot in real time; The depth sounder is mounted on the robot body and is used to measure the vertical distance between the underwater robot and the water surface; The propulsion system includes a longitudinal thruster arranged along the X-axis, a lateral adjustment thruster arranged along the Y-axis, and a vertical adjustment thruster arranged along the Z-axis, used to receive instructions from the motion control unit and drive the robot to move; The storage module is used to pre-store underwater tunnel structural parameters, including tunnel axis alignment data, cross-sectional dimension parameters, feature point coordinates, and preset safety offset range thresholds.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The underwater robot positioning and navigation method of the present invention has high accuracy, simple operation and strong applicability. It is especially suitable for zigzag underwater tunnels. Moreover, the method can be used to achieve positioning in underwater tunnels by simply modifying existing underwater robots, without the need for pre-modification of the tunnel (such as setting positioning markers). 2. The underwater robot positioning and navigation method in this invention uses a single-beam rangefinder to measure parameters for positioning. This avoids the problem of inaccurate positioning caused by the continuous accumulation of errors in its own measuring components during long-distance navigation, as well as by unexpected disturbances and attitude deviations caused by random underwater currents. This method further improves positioning accuracy by calibrating the measurement parameters of the single-beam rangefinder. 3. This invention employs multi-sensor fusion positioning, including a high-precision electronic compass and depth sounder, which improves positioning accuracy and stability, maintaining high positioning accuracy even during long-term operation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process for obtaining the first location information of the initial section of a tunnel according to an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the process of obtaining the first position information of a polygonal segment inside a tunnel, as provided in an embodiment of the present invention. Figure 3 This is a schematic diagram illustrating the process of obtaining the first position information of the end segment of the polyline inside the tunnel, as provided in an embodiment of the present invention. Figure 4 This is a schematic diagram of the internal cross-section of a tunnel provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the second location information acquisition process provided in an embodiment of the present invention; Figure 6 This is a front view of the underwater robot provided in an embodiment of the present invention; Figure 7This is a front view of the underwater robot provided in an embodiment of the present invention; Figure 8 This is a rear view of the underwater robot provided in an embodiment of the present invention; Figure 9 This is a left view of the underwater robot provided in an embodiment of the present invention; Figure 10 This is a right view of the underwater robot provided in an embodiment of the present invention; Figure 11 This is a top view of the underwater robot provided in an embodiment of the present invention; Figure 12 This is a schematic diagram of the tunnel structure in Embodiment 2 of the present invention; 1. Electronic compass; 2. Depth sounder; 3. First single-beam rangefinder; 301. First single-beam rangefinder in the positive X-axis direction; 302. First single-beam rangefinder in the negative X-axis direction; 4. Second single-beam rangefinder in the positive Y-axis direction; 5. Second single-beam rangefinder in the positive Z-axis direction. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0020] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0021] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0022] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0023] This invention provides a method for positioning and navigation of an underwater robot in a polygonal tunnel, comprising: determining first position information of the underwater robot at a first position in the tunnel based on measurement parameters of a first single-beam rangefinder and tunnel structural parameters; the measurement parameters of the first single-beam rangefinder are used to characterize the actual position of the underwater robot in a first direction; the first position information is used to characterize the relative position information between the underwater robot and the start and / or end point of the tunnel; determining second position information at the first position based on measurement parameters of a second single-beam rangefinder, the second position information being used to characterize the relative position information between the underwater robot and the tunnel wall within the tunnel; the measurement parameters of the second single-beam rangefinder are used to characterize the actual position of the underwater robot in a second direction plane; determining motion control commands for the underwater robot based on the first position information and the second position information; the motion control commands are used to control the movement of the underwater robot in the tunnel.

[0024] In some embodiments, when the error between the actual measured value and the tunnel structural parameters matches a preset error range, the underwater robot is controlled to move in the tunnel; when the error does not match the error range, the first single-beam ranging parameter and the second single-beam ranging parameter are corrected according to the error.

[0025] In some embodiments, the method further includes establishing a coordinate system, which includes: an origin and X-axis, Y-axis, and Z-axis derived from the origin; the geometric center point or motion control core point of the underwater robot is selected as the origin of the coordinate system, and the origin is bound to the motion state of the underwater robot in real time; X-axis: set along the tangent direction of the tunnel's central axis, and the positive direction of the X-axis is consistent with the preset travel direction of the underwater robot; when the tunnel turns left or right, the X-axis direction deflects synchronously with the tangent of the tunnel's central axis; when the tunnel rises or falls, the X-axis direction tilts synchronously with the slope of the tunnel's central axis; Y-axis: perpendicular to the X-axis and located within the horizontal cross-section of the tunnel, with the positive direction of the Y-axis pointing towards the left side wall of the tunnel, used to characterize the underwater robot's offset relative to the tunnel's central axis in the left-right direction; Z-axis: perpendicular to the tunnel cross-section formed by the X-axis and Y-axis, with the positive direction of the Z-axis pointing vertically downwards, used to characterize the underwater robot's offset relative to the tunnel's central axis in the up-down direction.

[0026] In some embodiments, determining the first position information of the underwater robot at a first position in the tunnel based on the measurement parameters of the first single-beam rangefinder and the tunnel structure parameters includes: transmitting ranging signals to the positive X-axis direction and the negative X-axis direction respectively using the first single-beam rangefinder, receiving the reflected signals and calculating the propagation time; determining the straight-line distance between the underwater robot and the tunnel inflection point in the positive X-axis direction and the straight-line distance between the underwater robot and the tunnel inflection point in the negative X-axis direction based on the signal propagation speed and propagation time; matching the distance information with the axial distances from the starting point to each feature point and the ending point preset in the tunnel structure parameters to determine the mileage interval in which the underwater robot is located, as the first position information, used to characterize the progressive position of the underwater robot relative to the starting point / ending point in the tunnel axial direction.

[0027] In some embodiments, determining the second position information of the underwater robot at the first position in the tunnel based on the measurement parameters of the second single-beam rangefinder includes: transmitting ranging signals in the positive Y-axis direction and the positive Z-axis direction respectively using the second single-beam rangefinder, receiving reflected signals in each direction and calculating the propagation time; determining the distance between the underwater robot and the left side wall of the tunnel and the distance between the underwater robot and the bottom wall of the tunnel based on the signal propagation speed and propagation time; calculating the lateral and vertical offsets of the underwater robot relative to the central axis of the tunnel based on the horizontal and vertical cross-sectional dimensions of the tunnel and the distances in each direction, and using the lateral and vertical offsets as the second position information to characterize the spatial position of the underwater robot relative to the central axis within the cross-section of the tunnel.

[0028] In some embodiments, controlling the movement of an underwater robot in a tunnel based on first and second position information includes: determining the current mileage position of the underwater robot along the tunnel axis based on the first position information, and planning the target travel path and speed parameters of the underwater robot in the X-axis direction by combining the axial orientation corresponding to the mileage interval in the tunnel structural parameters; calculating the deviation value of the current position relative to the tunnel center axis based on the lateral and vertical offsets in the second position information, and generating a lateral correction command in the Y-axis direction and a vertical leveling command in the Z-axis direction when the deviation value exceeds a preset safety threshold; and fusing the travel control command in the X-axis direction with the deviation correction commands in the Y and Z-axis directions to drive the underwater robot's propulsion system to work together, so that the robot can maintain its movement along the tunnel axis while maintaining a preset offset range relative to the center axis, thereby achieving autonomous navigation within the polygonal tunnel.

[0029] In some embodiments, the positioning and navigation method further includes: when the underwater robot is in a horizontal straight section or a horizontal turning section within the tunnel, acquiring the underwater robot's current actual heading angle in real time using an electronic compass; retrieving the preset heading angle of the tunnel's central axis corresponding to the horizontal section from the tunnel's structural parameters; comparing the actual heading angle with the preset heading angle to calculate the heading deviation value; generating a direction correction command based on the heading deviation value to drive the underwater robot's lateral propulsion system to adjust its movement direction, ensuring that while the underwater robot is moving along the tunnel axis, its offset relative to the tunnel's central axis is always maintained within a preset safe offset range.

[0030] In some embodiments, the positioning and navigation method further includes: when the underwater robot is in a horizontal straight section or a horizontal turning section within the tunnel, measuring the vertical distance between the underwater robot and the water surface using a depth sounder, comparing and calibrating the measured value with the vertical offset in the second position information, and correcting the position parameter in the Z-axis direction to improve the accuracy of the second position information; when the underwater robot is in a vertically ascending and descending section within the tunnel, measuring the vertical distance between the underwater robot and the water surface using a depth sounder, comparing and calibrating the measured value with the axial mileage parameter in the first position information, and correcting the position parameter in the X-axis direction to improve the accuracy of the first position information.

[0031] This invention also discloses an underwater robot suitable for polygonal underwater tunnels, comprising: Motion control unit, first single-beam rangefinder, second single-beam rangefinder, and propulsion system; The first single-beam rangefinder is used to acquire the first single-beam rangefinder measurement parameters of the underwater robot; the first single-beam rangefinder measurement parameters are used to characterize the actual position of the underwater robot in the first direction. The second single-beam rangefinder is used to acquire the measurement parameters of the underwater robot; the measurement parameters of the second single-beam rangefinder are used to characterize the actual position of the underwater robot in the second direction plane; the second direction plane is not parallel to the first direction; The motion control system is used to determine the first position information of the underwater robot in the tunnel at a first position based on the measurement parameters of the first single-beam rangefinder and the structural parameters of the tunnel structure, and to determine the second position information of the underwater robot in the first position based on the measurement parameters of the second single-beam rangefinder, and to determine the motion control command for the underwater robot based on the first position information and the second position information. The propulsion system is used to control the movement of the underwater robot in the tunnel according to motion control commands.

[0032] In some embodiments, the underwater robot includes: a robot body, a first single-beam rangefinder, a second single-beam rangefinder, an electronic compass, a depth sounder, a propulsion system, and a storage module; The robot body has a built-in motion control unit for executing the above-mentioned underwater robot positioning and navigation method applicable to polygonal underwater tunnels; The first single-beam rangefinder is installed at the ends of the robot body along the positive and negative X-axis directions. It is used to transmit ranging signals in the direction of the tunnel axis and receive reflected signals to obtain the distance information between the underwater robot and the turning point of the tunnel. The second single-beam rangefinder is installed at the positive Y-axis end and the positive Z-axis end of the robot body. It is used to transmit ranging signals to the left side wall and bottom wall of the tunnel and receive reflected signals to obtain the lateral and vertical distance information between the underwater robot and the tunnel wall. An electronic compass is mounted on the top of the robot body to collect the actual heading angle of the underwater robot in real time; The depth sounder is mounted on the robot body and is used to measure the vertical distance between the underwater robot and the water surface; The propulsion system includes a longitudinal thruster arranged along the X-axis, a lateral adjustment thruster arranged along the Y-axis, and a vertical adjustment thruster arranged along the Z-axis, used to receive instructions from the motion control unit and drive the robot to move; The storage module is used to pre-store underwater tunnel structural parameters, including tunnel axis alignment data, cross-sectional dimension parameters, feature point coordinates, and preset safety offset range thresholds.

[0033] Example 1 This invention also provides an embodiment of an underwater robot positioning and navigation method within a polygonal tunnel, to... Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 For example.

[0034] A method for underwater robot positioning and navigation in a zigzag tunnel, including: 101. The tunnel structure parameters are preloaded into the underwater robot's storage module to complete the initial configuration.

[0035] 102. When the underwater robot is in the initial section of the tunnel, since there is no effective reflective interface (such as the tunnel wall or a feature structure) in the negative X-axis direction (away from the preset travel direction), the first single-beam rangefinder can only collect ranging parameters in the positive X-axis direction (preset travel direction) (such as...). Figure 1 (As shown). At this point, by retrieving the theoretical axis length value of the initial segment from the tunnel structure parameters and performing a difference calculation with the measured single-beam ranging parameters in the positive X-axis direction, the first position information of the underwater robot in the tunnel axis direction (i.e., the mileage coordinates relative to the entrance starting point) can be calculated.

[0036] 103. The second single-beam rangefinder collects ranging parameters in the positive Y-axis direction (pointing to the left side wall of the tunnel) and the positive Z-axis direction (pointing to the bottom wall of the tunnel) (e.g. Figure 3 (As shown). At this point, by retrieving the theoretical values ​​of the horizontal cross-sectional width and vertical dimension corresponding to the initial segment from the tunnel structural parameters, and performing difference calculations with the measured single-beam ranging parameters in the positive Y-axis direction and the positive Z-axis direction, respectively: combining the difference between the theoretical value of the horizontal cross-sectional width and the measured distance in the Y-axis direction, the lateral offset of the robot relative to the tunnel's central axis is calculated; combining the difference between the theoretical value of the vertical dimension and the measured distance in the Z-axis direction, the vertical offset of the robot relative to the tunnel's central axis is calculated; the lateral and vertical offsets are used together as the second position information to characterize the underwater robot's spatial position relative to the central axis within the tunnel cross-section. The method for obtaining the second position information remains unchanged throughout the underwater robot's movement.

[0037] 104. When the underwater robot is located at the tunnel entrance, the first single-beam rangefinder is calibrated to adapt to the current water temperature, current, and tunnel wall material characteristics. If the measurement parameters of the first single-beam rangefinder are equal to the theoretical axial length of the initial tunnel section, the measurement parameters of the first single-beam rangefinder are accurate and no adjustment is needed. If the measurement parameters of the first single-beam rangefinder are not equal to the theoretical axial length of the initial tunnel section, the measurement parameters of the first single-beam rangefinder are inaccurate. The first single-beam rangefinder is then calibrated until its measurement parameters are accurate. Based on the calibration data of the first single-beam rangefinder, the second single-beam rangefinder is adjusted to adapt to the current tunnel environment (including water temperature, current, and tunnel wall material).

[0038] 105. Based on the first position information and the second position information, determine the motion control command for the underwater robot; the motion control command is used to control the movement of the underwater robot in the tunnel.

[0039] Motion control method: Use the underwater robot remote controller to send movement commands to the robot, and use the orientation buttons to control the robot to move up, down, left, and right, so that the robot returns to the original route.

[0040] 106. When the underwater robot is inside the tunnel's broken line segment, there are effective reflecting surfaces in both the positive and negative X-axis directions. The first single-wave rangefinder collects ranging parameters in the positive and negative X-axis directions (such as...). Figure 2 (As shown). Retrieve the preset structural parameters for this region from the storage module, including the theoretical axis length value between the front and rear reflecting interfaces within the current interval (theoretical axis length value = X-axis positive direction reflecting interface mileage value - X-axis negative direction reflecting interface mileage value). Verify the validity of the ranging data by checking whether the sum of the first single-beam rangefinder measurement parameters in the X-axis positive direction and the first single-beam rangefinder measurement parameters in the X-axis negative direction matches the theoretical axis length value. If the sum of the measurement parameters of the first single-beam rangefinder in the positive X-axis direction and the measurement parameters of the first single-beam rangefinder in the negative X-axis direction is within a preset threshold, the measurement parameters of the first single-beam rangefinder are deemed valid. If the sum of the measurement parameters of the first single-beam rangefinder in the positive X-axis direction and the measurement parameters of the first single-beam rangefinder in the negative X-axis direction is not within a preset threshold, the measurement parameters of the first single-beam rangefinder are deemed invalid, and the first single-beam rangefinder is calibrated until the measurement parameters of the first single-beam rangefinder are accurate. The second single-beam rangefinder is adjusted according to the calibration data of the first single-beam rangefinder to adapt to the current tunnel environment (including water temperature, water flow, tunnel wall material, etc.). Based on the measurement parameters of the first single-beam rangefinder in the positive X-axis direction and the first single-beam rangefinder in the negative X-axis direction, the position of the underwater robot on the axis of the broken line segment inside the tunnel is determined. Combined with the segment information contained in the tunnel structure parameters (such as the total number of tunnel segments, the length of the axis of each segment, the sequence number of the current segment and the start and end mileage), the first position information (i.e. the progressive mileage relative to the starting point of the tunnel) is obtained.

[0041] 107. When the underwater robot is at the end of the tunnel, the positive X-axis direction (preset travel direction) lacks an effective reflective interface due to its proximity to the tunnel's end point (e.g., the end point has no closed tunnel wall or is an open end). The first single-beam rangefinder can only collect ranging parameters in the negative X-axis direction (away from the preset travel direction). At this time, by retrieving the theoretical axial length value of the end section from the tunnel structure parameters (i.e., the axial distance from the start of the end section to the tunnel's end point), and combining it with the known mileage coordinates of the start of the end section (pre-stored in the segmented information of the tunnel structure parameters), and accumulating it with the measured single-beam ranging parameters in the negative X-axis direction, the first position information can be calculated: specifically, using the mileage of the start of the end section as a reference, adding the measured distance in the negative X-axis direction (i.e., the axial distance from the robot to the start of the end section) yields the robot's progressive mileage relative to the tunnel's start point.

[0042] Existing underwater robot positioning and navigation methods are unsuitable for long, zigzag tunnels in non-still water. Firstly, long, zigzag tunnels underwater have difficulty receiving satellite signals, rendering existing satellite navigation methods unusable. Furthermore, long-distance movement within the tunnel causes the underwater robot's inertial positioning and navigation system to accumulate errors, resulting in inaccurate positioning. The long length and zigzag shape of the tunnel also make it exceptionally difficult to place positioning markers within it. Additionally, the unexpected disturbances and attitude shifts caused by random underwater currents in non-still water environments introduce significant errors into traditional underwater robot inertial positioning and navigation systems. The impact or adhesion of silt in non-still water environments can also easily damage positioning markers placed within the tunnel. Therefore, existing satellite positioning methods, inertial positioning methods (gyroscopes or accelerometers, etc.), and methods for placing positioning coordinates within the tunnel are all unsuitable for underwater robot positioning and navigation in long, zigzag tunnels in non-still water environments.

[0043] The underwater robot positioning and navigation method provided by this invention can be applied to underwater robot positioning and navigation in long, zigzag underwater tunnels, in both calm and non-calm water environments. By making simple modifications to ordinary underwater robots, this method can be used for underwater robot positioning and navigation.

[0044] Example 2 This invention also discloses an embodiment of an underwater robot, such as... Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 As shown.

[0045] like Figure 12 As shown, taking a power station as an example, its tunnel cross-section is circular with an inner diameter of 0.75 meters. The direction along the tunnel axis is the x-axis, the vertical direction perpendicular to the tunnel axis is the y-axis, and the horizontal direction perpendicular to the tunnel axis is the z-axis. The robot dimensions are: length a along the x-axis, height b along the y-axis, and width c along the z-axis.

[0046] Based on the tunnel drawings, the tunnel can be divided into three sections according to its shape: an approximately horizontal section, a vertical section, and a horizontal section. These will be referred to as Tunnel Section 1, Tunnel Section 2, and Tunnel Section 3, respectively. It should be ensured that stable distance measurement and normal readings can be achieved both behind the robot in the initial section and in front of the robot in the final section. The lengths of the axes of each section can then be derived.

[0047] Depend on Figure 10As can be seen, the dead water level is 2785, and the water level at the tunnel's starting point is 2768.75, indicating a water depth of 16.25 meters. After the robot is lowered into the tunnel through the gate slot, the functions of the first single-beam rangefinder 301 and depth sounder 2 in the positive X-axis direction are activated. The robot's position is adjusted so that the depth sounder 2 reading d is 16.25 meters, ensuring that the robot is at the center of the tunnel in the Y-axis direction. The single-beam ranging readings l of the robot's second single-beam rangefinder 4 in the positive Y-axis direction and the second single-beam rangefinder 5 in the positive Z-axis direction are 0.75 / 2 - c / 2, ensuring that the robot is at the center of the tunnel in the Z-axis direction.

[0048] (1) Positioning of the robot in the tunnel cross section (i.e., ensuring that the robot does not touch the tunnel wall) 1) Tunnel Section 1 Onshore personnel operate the robot to move forward in the direction indicated by electronic compass 1. The ranging frequency of the first single-beam rangefinder 301 and depth sounder 2 in the positive X-axis direction is maintained at 5 times / m. Since the slope ratio of the horizontal section is i=0.05, the corresponding reading d of depth sounder 2 should be 16.25+0.05*x when the robot moves x meters. When the actual reading of depth sounder 2 is outside the range of [d-0.1, d+0.1], the operator should promptly adjust the position of the underwater robot to return it to the tunnel axis position.

[0049] 2) Turning section between tunnel section 1 and tunnel section 2 Upon reaching the starting point of the turning section, the water depth is 2785 - 2766.5 = 18.5 meters. This section is a circular arc with a radius of 30 meters, so when the robot moves forward x meters, the reading d corresponding to depth sounder 2 should be 18.5 + ( When the actual reading of depth sounder 2 is outside the range of [d-0.1, d+0.1], the operator should promptly adjust the position of the underwater robot to return it to the tunnel axis position. At the same time, the readings l of the robot's second single-beam rangefinder 4 in the positive Y-axis direction and the second single-beam rangefinder 5 in the positive Z-axis direction are 0.75 / 2-c / 2. If the actual reading is outside the range of [l-0.1, l+0.1], the operator should promptly adjust the position of the underwater robot to return the actual reading to the normal range, ensuring that it returns to the tunnel axis position.

[0050] 3) Tunnel Section 2 After the turning section, the robot arrives at the starting point of the vertical section. Elevation calculations indicate the water depth at the starting point is 48.7 meters. The robot continues along the axis, descending vertically. The electronic compass 1 is temporarily inactive; positioning within the tunnel is achieved using the depth sounder 2 and the second single-beam rangefinder 5 in the positive Z-axis direction. For every x meters the robot moves forward (i.e., every x meters it descends), the reading 'd' of the second single-beam rangefinder 5 in the positive Z-axis direction should be 48.7 + x. The methods for determining offset and operation have been described above and will not be repeated here.

[0051] 4) The turning section between tunnel section 2 and tunnel section 3 In the second turning section, the water depth is 2785 - 2621.2 = 163.8 meters. This section is a circular arc with a radius of 30 meters, so when the robot moves forward x meters, the reading d corresponding to depth sounder 2 should be 163.8 + 163.8 meters. The method for determining offset and its operation has been described above and will not be repeated here.

[0052] By using the depth sounder 2 and the second single-beam rangefinder 4 on the opposite side of the depth sounder along the positive Y-axis, as long as the two data readings from these two instruments are within the normal range, the underwater robot can be located to avoid colliding with the tunnel walls. The data measured by the second single-beam rangefinder 5 on the bottom of the robot along the positive Z-axis can be used as confirmation data and cross-checked with the data from the depth sounder 2.

[0053] 5) Tunnel Section 3 The starting water depth of this section is 193.8 meters. The positioning method for this section is similar to that of tunnel section 1, except that the reading d of depth sounder 2 should be maintained at 193.8. When the actual reading d of depth sounder 2 is outside the range of [193.8-0.1, 193.8+0.1], the operator should promptly adjust the position of the underwater robot to return it to the tunnel axis position. Meanwhile, before the tunnel section tightens, the readings l of the robot's second single-beam rangefinder 4 in the positive Y-axis direction and the second single-beam rangefinder 5 in the positive Z-axis direction are 0.75 / 2-c / 2. If the actual reading is outside the range of [l-0.1, l+0.1], the operator should adjust the position of the underwater robot in time to bring the actual reading back to the normal range and ensure that it returns to the position of the tunnel axis.

[0054] ① Tunnel diameter change section The tunnel diameter change section refers to the section where the pipe diameter changes between chainage 0+325.71 and 0+340.71. After the robot enters the tunnel diameter change section, it should simultaneously use the depth sounder 2, the second single-beam rangefinder 4 in the positive Y-axis direction, and the second single-beam rangefinder 5 in the positive Z-axis direction for positioning. That is, while the depth sounder 2 reading d is maintained at 193.8 meters, the readings of the second single-beam rangefinder 4 in the positive Y-axis direction and the second single-beam rangefinder 5 in the positive Z-axis direction should be basically consistent, with the reading l decreasing linearly from 0.75 / 2-c / 2 to 0.59 / 2-c / 2. The method for judging offset and operation has been described above and will not be repeated here.

[0055] ②Tunnel Terminal The robot then enters the tunnel terminal, where the tunnel diameter is 0.59 meters. The reading l of the first single-beam rangefinder 302 in the negative X-axis direction should be 0.59 / 2 - c / 2. The offset and operation method have been described above and will not be repeated here. At this point, the robot safely exits the tunnel.

[0056] (2) Positioning of the robot along the tunnel axis 1) Tunnel Section 1 After the robot is lowered into tunnel section 1 from the gate slot, the single-beam rangefinder 3, the second single-beam rangefinder 4 in the positive Y-axis direction, the second single-beam rangefinder 5 in the positive Z-axis direction, and the depth sounder 2 are activated. The robot's position is adjusted, and before moving along the axis, the first single-beam rangefinder 301 in the positive X-axis direction at the front of the robot is used to measure the distance, ensuring that the reading matches the length of the axis section obtained from the drawing. Subsequently, the land-based staff operates the robot to move in the direction indicated by the electronic compass 1. The ranging frequency of the second single-beam rangefinder 4 in the positive Y-axis direction, the second single-beam rangefinder 5 in the positive Z-axis direction, and the depth sounder 2 is maintained at 5 times / m. There are two rangefinders in the X-axis direction (i.e., the axis direction) (the first single-beam rangefinder 301 in the positive X-axis direction and the first single-beam rangefinder 302 in the negative X-axis direction), which can measure distances forward and backward. The position of the robot in the tunnel can be determined by the distance d1 measured by the first single-beam rangefinder 301 in the positive X-axis direction, and the reading d2 of the rear rangefinder is used as a check, satisfying d1+d2+a=axis segment length.

[0057] 2) Turning section between tunnel section 1 and tunnel section 2 As the robot approaches the turning section, the reading of the first single-beam rangefinder 301 in the positive X-axis direction decreases. At this time, the depth sounder 2 and the second single-beam rangefinder 4 in the positive Y-axis direction are used to locate the robot's position in the tube, assisting the robot to slowly and safely pass through the turning section.

[0058] 3) Tunnel Section 2 After entering the vertical tunnel section, the robot is positioned using the reading from the first single-beam rangefinder 301 in the positive X-axis direction. The reading d2 from the rear rangefinder is used for verification, ensuring that d1 + d2 + a = length of the axis segment. At this point, a secondary verification can be performed using the reading from the depth sounder 2 to ensure accurate robot positioning.

[0059] 4) Remaining turning section and tunnel section 3 The final tunnel turning section and tunnel section 3 are located in the same way as the turning section between tunnel sections 1 and 2 and the tunnel section 1, so they will not be described again here.

[0060] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0061] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for underwater robot positioning and navigation in a polygonal tunnel, characterized in that, include: The first position information of the robot in the tunnel is determined based on the measurement parameters of the first single-beam rangefinder and the tunnel structure parameters. The parameters measured by the first single-beam rangefinder are used to characterize the actual position of the underwater robot in the first direction; The first position information is used to characterize the relative position information between the underwater robot and the starting point and / or ending point of the tunnel; The second position information is determined based on the measurement parameters of the second single-beam rangefinder at the first position. The second position information is used to characterize the relative position information of the underwater robot between the tunnel wall and the tunnel. The second single-beam rangefinder measures parameters to characterize the actual position of the underwater robot in the second direction plane; Motion control commands for the underwater robot are determined based on the first position information and the second position information; the motion control commands are used to control the movement of the underwater robot in the tunnel.

2. The underwater robot positioning and navigation method in a polygonal tunnel according to claim 1, characterized in that, When the error between the actual measured value and the tunnel structural parameters matches the preset error range, the underwater robot is controlled to move in the tunnel; when the error does not match the error range, the first single-beam ranging parameters and the second single-beam ranging parameters are corrected according to the error.

3. The underwater robot positioning and navigation method in a polygonal tunnel according to claim 2, characterized in that, Establish a coordinate system, including: an origin and X-axis, Y-axis, and Z-axis derived from the origin; select the geometric center point or motion control core point of the underwater robot as the origin, and bind the origin to the motion state of the underwater robot in real time; X-axis: set along the tangent direction of the tunnel's central axis, and the positive direction of the X-axis is consistent with the underwater robot's preset travel direction; when the tunnel turns left or right, the X-axis direction deflects synchronously with the tangent of the tunnel's central axis; when the tunnel rises or falls, the X-axis direction tilts synchronously with the slope of the tunnel's central axis; Y-axis: perpendicular to the X-axis and located within the horizontal cross-section of the tunnel, with the positive direction of the Y-axis pointing towards the left side wall of the tunnel, used to characterize the underwater robot's offset relative to the tunnel's central axis in the left-right direction; Z-axis: perpendicular to the tunnel cross-section formed by the X-axis and Y-axis, with the positive direction of the Z-axis pointing vertically downwards, used to characterize the underwater robot's offset relative to the tunnel's central axis in the up-down direction.

4. The underwater robot positioning and navigation method in a polygonal tunnel according to claim 3, characterized in that, The first position information of the underwater robot in the tunnel, determined based on the measurement parameters of the first single-beam rangefinder and the tunnel structure parameters, includes: transmitting ranging signals in the positive and negative X-axis directions respectively using the first single-beam rangefinder, receiving reflected signals and calculating propagation time; determining the straight-line distance between the underwater robot and the tunnel inflection point in the positive X-axis direction and the straight-line distance between the underwater robot and the tunnel inflection point in the negative X-axis direction based on the signal propagation speed and propagation time; matching the distance information with the axial distances from the starting point to each feature point and the ending point preset in the tunnel structure parameters to determine the mileage interval in which the underwater robot is located, which serves as the first position information and is used to characterize the progressive position of the underwater robot relative to the starting point / ending point in the tunnel axis direction.

5. The underwater robot positioning and navigation method in a polygonal tunnel according to claim 4, characterized in that, The second position information of the underwater robot in the tunnel, determined based on the measurement parameters of the second single-beam rangefinder, includes: transmitting ranging signals in the positive Y-axis and positive Z-axis directions respectively using the second single-beam rangefinder, receiving reflected signals in each direction and calculating the propagation time; determining the distance between the underwater robot and the left side wall of the tunnel and the distance between the underwater robot and the bottom wall of the tunnel based on the signal propagation speed and propagation time; calculating the lateral and vertical offsets of the underwater robot relative to the central axis of the tunnel based on the horizontal and vertical cross-sectional dimensions of the tunnel and the distances in each direction, and using the lateral and vertical offsets as the second position information to characterize the spatial position of the underwater robot relative to the central axis within the tunnel cross-section.

6. The underwater robot positioning and navigation method in a polygonal tunnel according to claim 5, characterized in that, Controlling the movement of an underwater robot in a tunnel based on first and second position information includes: determining the current mileage position of the underwater robot along the tunnel axis based on the first position information, and planning the target travel path and speed parameters of the underwater robot in the X-axis direction by combining the axis orientation corresponding to this mileage interval in the tunnel structural parameters; calculating the deviation value of the current position relative to the tunnel center axis based on the lateral and vertical offset values ​​in the second position information, and generating lateral correction commands in the Y-axis direction and vertical leveling commands in the Z-axis direction when the deviation value exceeds a preset safety threshold; and fusing the travel control commands in the X-axis direction with the deviation correction commands in the Y and Z-axis directions to drive the underwater robot's propulsion system to work together, so that the robot can maintain its movement along the tunnel axis while maintaining a preset offset range relative to the center axis, thus achieving autonomous navigation within the polygonal tunnel.

7. The underwater robot positioning and navigation method in a polygonal tunnel according to claim 6, characterized in that, The positioning and navigation method also includes: when the underwater robot is in a horizontal straight section or a horizontal turning section within the tunnel, the current actual heading angle of the underwater robot is collected in real time using an electronic compass; the preset heading angle of the tunnel center axis corresponding to the horizontal section is retrieved from the tunnel structural parameters; the actual heading angle is compared with the preset heading angle to calculate the heading deviation value; and a direction correction command is generated based on the heading deviation value to drive the underwater robot's lateral propulsion system to adjust its movement direction, ensuring that while the underwater robot is moving along the tunnel axis, its offset relative to the tunnel center axis is always maintained within a preset safe offset range.

8. The underwater robot positioning and navigation method in a suitable zigzag tunnel according to claim 6, characterized in that, The positioning and navigation method also includes: when the underwater robot is in a horizontal straight section or a horizontal turning section within the tunnel, measuring the vertical distance between the underwater robot and the water surface using a depth sounder, comparing and calibrating this measurement value with the vertical offset in the second position information, and correcting the position parameters in the Z-axis direction to improve the accuracy of the second position information; when the underwater robot is in a vertically ascending and descending section within the tunnel, measuring the vertical distance between the underwater robot and the water surface using a depth sounder, comparing and calibrating this measurement value with the axis mileage parameter in the first position information, and correcting the position parameters in the X-axis direction to improve the accuracy of the first position information.

9. An underwater robot suitable for use in polygonal underwater tunnels, characterized in that, include: Motion control unit, first single-beam rangefinder, second single-beam rangefinder, and propulsion system; The first single-beam rangefinder is used to acquire the first single-beam rangefinder measurement parameters of the underwater robot; the first single-beam rangefinder measurement parameters are used to characterize the actual position of the underwater robot in the first direction. The second single-beam rangefinder is used to acquire the measurement parameters of the second single-beam rangefinder of the underwater robot; the measurement parameters of the second single-beam rangefinder are used to characterize the actual position of the underwater robot in the second direction plane. The second directional plane is perpendicular to the first direction; The motion control system is used to determine the first position information of the underwater robot in the tunnel at a first position based on the measurement parameters of the first single-beam rangefinder and the structural parameters of the tunnel structure, and to determine the second position information of the underwater robot in the first position based on the measurement parameters of the second single-beam rangefinder, and to determine the motion control command for the underwater robot based on the first position information and the second position information. The propulsion system is used to control the movement of the underwater robot in the tunnel according to motion control commands.

10. The underwater robot suitable for polygonal underwater tunnels according to claim 9, characterized in that, include: The robot body has a built-in motion control unit for executing the underwater robot positioning and navigation method for a polygonal underwater tunnel as described in any one of claims 1-8. The first single-beam rangefinder is installed at the ends of the robot body along the positive and negative X-axis directions. It is used to transmit ranging signals in the direction of the tunnel axis and receive reflected signals to obtain the distance information between the underwater robot and the turning point of the tunnel. The second single-beam rangefinder is installed at the positive Y-axis end and the positive Z-axis end of the robot body. It is used to transmit ranging signals to the left side wall and bottom wall of the tunnel and receive reflected signals to obtain the lateral and vertical distance information between the underwater robot and the tunnel wall. An electronic compass, mounted on the top of the robot's main body, is used to collect the underwater robot's actual heading angle in real time; A depth sounder, mounted on the robot's main body, is used to measure the vertical distance between the underwater robot and the water surface. The propulsion system includes a longitudinal thruster arranged along the X-axis, a lateral adjustment thruster arranged along the Y-axis, and a vertical adjustment thruster arranged along the Z-axis, for receiving instructions from the motion control unit and driving the robot to move; The storage module is used to pre-store underwater tunnel structural parameters, including tunnel axis alignment data, cross-sectional dimension parameters, feature point coordinates, and preset safety offset range thresholds.

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