A robot and cleaning method for underwater cylindrical pier surface cleaning

Abstract

The application discloses a robot and a cleaning method for underwater cylindrical pier surface cleaning, wherein the robot comprises a robot body, a power module, an underwater mechanical arm, a vision module, a high-pressure water gun, a cleaning brush module and a fastening part. The robot is attached to the pier surface and can move in any direction along the surface. The underwater mechanical arm is equipped with a high-pressure water gun and a cleaning brush module at the tail end for cooperative work. The high-pressure water gun is used for large-area cleaning of the underwater cylindrical pier surface, and the cleaning brush module is used for small-range fine cleaning of the underwater cylindrical pier surface. The cleaning brush module is composed of a cleaning brush head and a six-dimensional force sensor, and the control method of the underwater mechanical arm adopts admittance control. The contact force between the cleaning brush head and the underwater cylindrical pier surface is adjusted in real time during the cleaning process, which can minimize the damage to the pier body compared with manual cleaning, and can replace manual work to achieve comprehensive cleaning of the cylindrical pier surface in a complex underwater environment, ensuring personnel safety and improving work efficiency.

Description

Technical Field

[0001] This invention relates to the field of underwater bridge maintenance robot technology, specifically to a robot and cleaning method for cleaning the surface of underwater cylindrical bridge piers. Background Technology

[0002] Underwater bridge piers are subject to prolonged immersion in water, erosion by water flow, and the adhesion of aquatic organisms, which can lead to structural defects such as cracks, damage, and corrosion, reducing the structural stability and service life of the bridge. Timely inspection and maintenance of underwater bridge piers are crucial, and cleaning surface deposits is a key step.

[0003] Currently, the surface cleaning of underwater bridge piers mainly relies on manual labor by divers, which is limited by working depth and time, carries high risks, and has low efficiency. There is currently a lack of automated equipment to replace manual labor in this field. Summary of the Invention

[0004] This invention addresses the problems of existing technologies by proposing a robot and cleaning method for cleaning the surface of underwater cylindrical bridge piers.

[0005] The technical solution of this invention is:

[0006] A robot and cleaning method for cleaning the surface of underwater cylindrical bridge piers are characterized by comprising fastening components, a power module, a robot body, a cleaning module, an underwater robotic arm, a vision module, and a high-pressure water gun. The robot body consists of a top cover and a base, with a reserved space between them for installing other components. The robot body is made of titanium alloy, which features high strength, high rigidity, and low density, greatly improving the flexibility of the underwater robot. The power module comprises six sets, installed in the reserved space between the robot's top cover and base. Four sets are symmetrically installed horizontally, and two sets are symmetrically installed vertically, with each set at a 40° angle, for flexible movement of the robot along the bridge pier. The fastening components consist of two sets, each composed of a large fastening arm, a secondary fastening arm, a small fastening arm, and clamping wheels. The large and secondary fastening arms are installed parallel to the small fastening arm to control the clamping wheels to adhere tightly to the underwater bridge pier surface during cleaning operations, ensuring operational stability.

[0007] As a further improvement of the present invention, the vision module consists of a base, a camera, and an illumination component. The camera and the illumination component are respectively installed at both ends of the base. By rotating the base, the illumination component provides lighting conditions for the camera, providing comprehensive and accurate visual information even in turbid water environments for real-time display of the cleaning process. The underwater robotic arms are symmetrically distributed on both sides of the robot body. The cleaning module consists of a six-dimensional force sensor and a cleaning brush head. The six-dimensional force sensor is installed at the end of one set of underwater robotic arms to sense the six-dimensional force when the cleaning brush head contacts the underwater bridge pier during cleaning, providing usable information for achieving precise adaptive variable admittance control. The cleaning module and the high-pressure water gun are respectively installed at the ends of the two sets of underwater robotic arms, and their directions can be adjusted to cooperate in underwater cleaning of the bridge pier.

[0008] The cleaning method for a robot used for cleaning the surface of underwater cylindrical bridge piers includes the following steps:

[0009] Step 1: The operator manipulates the crane to lower the underwater robot to a water area with low water flow near the underwater bridge pier. According to the pre-planned route, the underwater robot is remotely driven to the work area via cable. Then, the operator remotely controls the fastening component's main arm and auxiliary arm to work together to control the clamping wheel to stick to the surface of the underwater cylindrical bridge pier, so that the underwater robot can grip the surface of the bridge pier.

[0010] Step 2: The operator remotely activates the power module, vision module, and high-pressure water gun via cable to prepare for the cleaning operation. Since the cleaning range of the high-pressure water gun is limited, it can only clean one-quarter of the entire cylindrical pier surface each time. Therefore, a total of four rounds of cleaning are required. After each round of cleaning is completed, the power module robot moves 90° clockwise around the pier to reach the uncleaned area and start a new round of cleaning until all four rounds of cleaning are completed.

[0011] Step 3: Start the cleaning operation. The power module controls the robot to crawl along the planned path. During the crawling process, the high-pressure water gun mounted on the end of the robotic arm is used to wash the surface of the path over a large area. The vision module transmits real-time images. When it finds an area that needs to be cleaned, it turns off the power module to stop the robot from moving, turns off the high-pressure water gun, and activates the cleaning module.

[0012] Step 4: The cleaning module is used for fine cleaning of small areas. After cleaning is completed, the cleaning module is stopped, and the power module and high-pressure water gun are turned on to continue the cleaning work. Adaptive variable admittance control is incorporated into the cleaning module's operation to adjust the force applied when the cleaning brush head contacts the surface of the underwater cylindrical bridge pier, minimizing damage to the pier's surface. The control system employs an inner loop strategy based on position control and an outer loop strategy based on force control. The contact force between the six-dimensional force sensor and the external environment is used to generate an additional position using an adaptive variable admittance algorithm. This additional position is then used to correct the pre-set position trajectory and finally fed into the inner loop of position control to complete the final position control. The admittance control model is as follows:

[0013]

[0014] Step 5: After the robot completes one round of cleaning, the power module controls the robot to move 90° clockwise around the bridge pier to reach the uncleaned area and start a new round of cleaning. This process continues until all four rounds of cleaning are completed. The robot then returns to the deployment point along the same path it came from, and is retrieved by a crane. The cleaning process is then complete.

[0015] The beneficial effects of this invention are:

[0016] The robot of the present invention for cleaning the surface of underwater cylindrical bridge piers can replace manual labor in complex underwater environments to crawl on the surface of cylindrical bridge piers and clean up attachments, ensuring personnel safety and improving work efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the underwater robot of the present invention installed on an underwater cylindrical bridge pier.

[0018] Figure 2 This is a side view of the underwater robot of the present invention;

[0019] Figure 3 This is a top view of the underwater robot of the present invention;

[0020] Figure 4 This is a schematic diagram of the vision module system of the underwater robot of the present invention;

[0021] Figure 5 This is a schematic diagram of the fastening component system of the underwater robot of the present invention;

[0022] Figure 6 This is a system block diagram of the underwater robot cleaning module control method of the present invention;

[0023] Figure 7 This is a path planning diagram for the cleaning operation of the underwater robot of the present invention.

[0024] Figure 8This is a flowchart illustrating the cleaning operation process of the underwater robot of the present invention.

[0025] In the diagram: 1. Fastening component; 11. Fastening component upper arm; 12. Fastening component secondary arm; 13. Fastening component lower arm; 2. Power module; 3. Robot body; 4. Cleaning module; 5. Underwater robotic arm; 6. Vision module; 61. Base; 62. Camera; 63. Lighting component; 7. High-pressure water gun; 8. Underwater cylindrical pier. Specific implementation methods

[0026] The invention will now be further described with reference to the accompanying drawings.

[0027] As shown in the figure, a robot for cleaning the surface of underwater cylindrical bridge piers includes a fastening component 1, a power module 2, a robot body 3, a cleaning module 4, an underwater robotic arm 5, a vision module 6, and a high-pressure water gun 7. The robot body 3 consists of a top cover and a base, with a reserved space between them for installing other components. The robot body 3 is made of titanium alloy, which has the characteristics of high strength, high rigidity, and low density, greatly improving the flexibility of the underwater robot. There are six power modules 2, which are installed in the reserved space between the robot's top cover and base. Four of them are symmetrically installed in the horizontal direction, and two are symmetrically installed in the vertical direction, with an installation angle of 40°, allowing the robot to move flexibly along the surface of the bridge pier. The fastening component 1 consists of two sets, which are respectively composed of a fastening component main arm 11, a fastening component secondary arm 12, a fastening component small arm 13, and a clamping wheel 14. The fastening component main arm 11 and the fastening component secondary arm 12 are installed parallel to the fastening component small arm 13 to control the clamping wheel to stick to the surface of the underwater bridge pier during the cleaning operation, ensuring its working stability.

[0028] In this embodiment, the vision module 6 consists of a base 61, an illumination component 62, and a camera 63. The illumination component 62 and the camera 63 are respectively installed at both ends of the base 61. By rotating the base 61, the illumination component 62 provides illumination for the camera 63, providing comprehensive and accurate visual information even in turbid water environments for real-time display of the cleaning process. The underwater robotic arms 5 are symmetrically distributed on both sides of the robot body 3. The cleaning module 4 and the high-pressure water gun 7 are respectively installed at the ends of the two sets of underwater robotic arms 5, and their directions can be adjusted. The high-pressure water gun 7 is used for large-area cleaning of the bridge pier surface, while the cleaning module 4 is used for fine cleaning of small areas. The two work together to clean the bridge pier underwater. The cleaning module 4 consists of a six-dimensional force sensor and a cleaning brush head. The six-dimensional force sensor is used to sense the six-dimensional force when the cleaning brush head contacts the underwater bridge pier during cleaning, providing usable information for achieving precise adaptive variable admittance control.

[0029] A robot and cleaning method for cleaning the surface of underwater cylindrical bridge piers, including the following steps:

[0030] Step 1: The operator uses a crane to lower the underwater robot to a water area with low current near the underwater bridge pier. According to the pre-planned route, the underwater robot is remotely driven to the work area via cable. Then, the operator remotely controls the main arm and auxiliary arm of the fastening component to work together to control the clamping wheel to stick to the surface of the underwater cylindrical bridge pier, so that the underwater robot can grip the surface of the bridge pier.

[0031] Step Two: The operator remotely activates the power module, vision module, and high-pressure water gun via cable to prepare for the cleaning operation. Since the high-pressure water gun has a limited cleaning range, it can only clean one-quarter of the entire cylindrical pier surface at a time. Therefore, four rounds of cleaning are required. After each round of cleaning, the power module moves 90° clockwise around the pier to reach the uncleaned area and begin a new round of cleaning until all four rounds of cleaning are completed. The cleaning path planning diagram is shown below. Figure 8 As shown;

[0032] Step 3: Start the cleaning operation. The power module controls the robot to crawl along the planned path. During the crawling process, the high-pressure water gun mounted on the end of the robotic arm is used to wash the surface of the path in a large area. The vision module transmits real-time images. When it finds an area that needs to be cleaned, it turns off the power module to stop the robot from moving, turns off the high-pressure water gun, and turns on the cleaning module.

[0033] Step 4: The cleaning module is used for fine cleaning of small areas. After cleaning is complete, the cleaning module is stopped, and the power module and high-pressure water gun are turned on to continue the cleaning work. Adaptive variable admittance control is incorporated into the cleaning module's operation to adjust the force applied when the cleaning brush head contacts the surface of the underwater cylindrical bridge pier, minimizing damage to the underwater cylindrical bridge pier surface. The admittance control model is expressed as:

[0034]

[0035] Where ΔF=F r -F ext F ext F represents the environmental force acquired by a six-dimensional force sensor in the tool coordinate system. r For expectancy; X c The controller outputs the target trajectory, X r Here is the reference trajectory for the robotic arm; K is the diagonal matrix of stiffness coefficients, B is the diagonal matrix of damping coefficients, and M is the diagonal matrix of inertia coefficients.

[0036] Due to the initial environmental location X e Can replace X r Then let e = x c -x e Therefore, admittance control is expressed as:

[0037]

[0038] Where ΔF(t), e(t) is time-varying. To compensate for the time-varying contact force error, an adaptive variable admittance coefficient method is introduced. This method uses variable damping to achieve the adaptive variable admittance coefficient. The adaptive damping change rate is established based on the contact force error, the cumulative force error, and the force error rate, thus enabling adaptive dynamic adjustment of the damping coefficient. The adaptive damping change law is:

[0039]

[0040] Where b0 is the initial value of the damping coefficient, Δb(t) is the rate of change of the adaptive damping coefficient, and b p b is the force error proportional gain coefficient. d The differential gain coefficient for force error, ε = 10 -8 It is a constant to prevent the denominator from being zero.

[0041] The control system employs an inner-loop strategy based on position control and an outer-loop strategy based on force control. It detects the contact force between a six-dimensional force sensor and the external environment, uses an adaptive variable admittance algorithm to generate an additional position, corrects the pre-set position trajectory with this additional position, and finally sends it to the inner-loop position control to complete the final position control. The control block diagram is shown below. Figure 6 As shown.

[0042] Step 5: After the robot completes one round of cleaning, the power module controls the robot to move 90° clockwise around the bridge pier to reach the uncleaned area and start a new round of cleaning. This process continues until all four rounds of cleaning are completed. The robot then returns to the deployment point along the same path it came from, and is retrieved by a crane. The cleaning process is then complete.

[0043] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A robot for cleaning the surface of underwater cylindrical bridge piers, characterized in that: The system includes fastening components (1), a power module (2), a robot body (3), a cleaning module (4), an underwater robotic arm (5), a vision module (6), and a high-pressure water gun (7). The robot body (3) consists of a top cover and a base, with a reserved space between them for installing other components. The robot body (3) is made of titanium alloy. The power module (2) consists of six sets, installed in the reserved space between the robot top cover and the base. Four sets are symmetrically installed in the horizontal direction, and two sets are symmetrically installed in the vertical direction. The installation angle is 40°, which allows the robot to move flexibly along the surface of the bridge pier. The fastening components (1) consist of two sets, which are respectively composed of a fastening component upper arm (11), a fastening component secondary arm (12), a fastening component lower arm (13), and a clamping wheel (14). The fastening component upper arm (11) and the fastening component secondary arm (12) are installed in parallel on the fastening component lower arm (13) to control the clamping wheel to stick to the surface of the underwater bridge pier during the cleaning operation. The vision module (6) consists of a base (61), an illumination component (62), and a camera (63). The illumination component (62) and the camera (63) are respectively installed at both ends of the base (61). By rotating the base (61), the illumination component (62) provides illumination for the camera (63). It can also provide all-round accurate visual information in turbid water environment for real-time display of the cleaning process. The underwater robotic arms (5) are symmetrically distributed on both sides of the robot body (3). The cleaning module (4) and the high-pressure water gun (7) are respectively installed at the ends of the two sets of underwater robotic arms (5). The direction can be adjusted. The high-pressure water gun (7) is used for large-area cleaning of the bridge pier surface, and the cleaning module (4) is used for small-area fine cleaning. The two work together to clean the bridge pier underwater. The cleaning module (4) consists of a six-dimensional force sensor and a cleaning brush head. The six-dimensional force sensor is used to sense the six-dimensional force when the cleaning brush head contacts the underwater bridge pier during cleaning, providing usable information for achieving accurate adaptive variable admittance control. The cleaning method for the robot used for cleaning the surface of underwater cylindrical bridge piers includes the following steps: Step 1: The operator manipulates the crane to lower the robot to a water area with low water flow near the underwater bridge pier. According to the pre-planned route, the underwater robot is remotely driven to the work area via cable. Then, the operator remotely controls the fastening component (1) to make the fastening component arm (11) and fastening component auxiliary arm (12) control the fastening component small arm (13) to work together to control the clamping wheel to stick to the surface of the underwater cylindrical bridge pier, so that the underwater robot can grab the surface of the bridge pier. Step 2: The operator remotely turns on the power module (2), vision module (6) and high-pressure water gun (7) via cable to prepare for the cleaning operation. Since the cleaning range of the high-pressure water gun (7) is limited, it can only clean one-quarter of the entire cylindrical pier surface each time. Therefore, a total of four rounds of cleaning are required. After each round of cleaning is completed, the robot of the power module (2) moves 90° clockwise around the pier to reach the uncleaned area to carry out a new round of cleaning work until all four rounds of cleaning operations are completed. Step 3: Start the cleaning operation. The power module (2) controls the robot to crawl along the planned path. During the crawling process, the high-pressure water gun (7) mounted on the end of the robotic arm is used to wash the surface of the path in a large area. The vision module (6) transmits real-time images. When it finds an area that needs to be cleaned, it turns off the power module (2) to stop the robot from moving, turns off the high-pressure water gun (7), and turns on the cleaning module (4). Step 4: The cleaning module (4) is mainly used for fine cleaning of small areas. After cleaning is completed, the cleaning module (4) is stopped, and the power module (2) and high-pressure water gun (7) are turned on to continue cleaning along the planned path. Adaptive variable admittance control is added when the cleaning module (4) is working to adjust the force used when the cleaning brush head contacts the surface of the underwater cylindrical bridge pier, so as to minimize the damage to the surface of the underwater cylindrical bridge pier. The admittance control model is expressed as: in , Environmental forces in the tool coordinate system acquired by a six-dimensional force sensor. For the power of expectation; Output the target trajectory to the controller. Here is the reference trajectory for the robotic arm; K is the diagonal matrix of stiffness coefficients, B is the diagonal matrix of damping coefficients, and M is the diagonal matrix of inertia coefficients. Due to the initial environmental location Can replace Then another Therefore, admittance control is expressed as: in , , , Both are time-varying. To compensate for the time-varying contact force error, an adaptive variable admittance coefficient method is introduced. This method uses variable damping to achieve the adaptive variable admittance coefficient. The adaptive damping change rate is established based on the contact force error, the cumulative force error, and the force error rate, thus enabling adaptive dynamic adjustment of the damping coefficient. The adaptive damping change law is: in, The initial value of the damping coefficient. The rate of change of the adaptive damping coefficient. This is the force error proportional gain coefficient. The differential gain coefficient for force error. It is a constant to prevent the denominator from being zero. The control system adopts an inner loop strategy based on position control and an outer loop strategy based on force control. It detects the contact force between the six-dimensional force sensor and the external environment, uses an adaptive variable admittance algorithm to generate an additional position, corrects the pre-set position trajectory with this additional position, and finally sends it into the inner loop of position control to complete the final position control. Step 5: After the robot completes one round of cleaning, the power module (2) controls the robot to move 90° clockwise around the bridge pier and reach the uncleaned area to carry out a new round of cleaning work until all four rounds of cleaning work are completed. The robot returns to the drop point according to the path it came from, and the robot is retrieved by a crane. The entire cleaning process is over.

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