Control method and system of hull cleaning robot

Abstract

The invention relates to the technical field of robot control, and discloses a control method and system for a hull cleaning robot, and the method comprises the steps: collecting the first rotating speed of a left driving wheel in real time through a left-end incremental encoder, and collecting the second rotating speed of a right driving wheel in real time through a right-end incremental encoder; based on the first rotating speed, the second rotating speed and the driving wheel distance between the left driving wheel and the right driving wheel, the pose of the target robot is calculated in the motion mode; a positioning system is constructed through the laser transmitter and the laser receiver, and the positioning system is used for correcting the position coordinates of the target robot through an iterative algorithm; the ship body is divided into four quadrants, seven-step movement is repeatedly executed in each quadrant according to an N-shaped path, and the ship body is cleaned through the seven-step movement; the problems that an existing cleaning robot control method is low in cleaning efficiency and large in potential safety hazard are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of robot control, and in particular to a control method and system of a ship hull cleaning robot. BACKGROUND

[0002] In recent years, international trade has shown a rapid development trend, and the size and number of ocean-going cargo ships have shown a significant growth trend. At present, the hull wall of large ships is mostly made of steel material. However, during the driving process of large ships, the surface is easily affected by the corrosion and oxidation of seawater. Therefore, in order to prolong the service life of the hull, it is necessary to regularly polish and remove rust on the hull wall.

[0003] The global shipping industry spends nearly 10 billion US dollars on ship cleaning every year, and the cost of cleaning large cargo ships in dry docks is as high as 700,000 yuan. At present, the rust removal and maintenance work of the steel wall of the ship is mainly completed by professional service companies. These service companies usually arrange workers to use a climbing car or a scaffold and carry rust removal and polishing equipment to carry out maintenance work. However, manual wall rust removal and maintenance work has many problems, which are not only limited by working conditions and environment, but also affected by the technical level of workers. For example, the cost of manual rust removal is high, high-altitude operation has safety hazards, and workers may be exposed to toxic and harmful gases and radioactive elements during operation, which pose a potential threat to the health of workers. In addition, some special positions of the equipment are difficult to access, and manual maintenance cannot be effectively carried out, which brings great safety hazards to the normal operation of the equipment.

[0004] Therefore, in order to improve the work efficiency and reduce the labor intensity, it is of great practical significance to carry out research on the ship hull cleaning robot. SUMMARY

[0005] The present application provides a control method and system of a ship hull cleaning robot to solve the problems of low cleaning efficiency and high safety hazards of the existing cleaning robot control method.

[0006] In order to achieve the above-mentioned purpose, the present application realizes the following technical solutions: In a first aspect, the present application provides a control method of a ship hull cleaning robot, comprising: The first speed of the left drive wheel is collected in real time by the left end incremental encoder, the second speed of the right drive wheel is collected in real time by the right end incremental encoder, and the pose of the target robot is calculated in the motion mode based on the first speed, the second speed and the drive wheel spacing between the left drive wheel and the right drive wheel. A positioning system is constructed by a laser emitter and a laser receiver, and an iterative algorithm is used to correct the position coordinates of the target robot by using the positioning system. The hull is divided into four quadrants, and a seven-step motion is repeatedly performed in each quadrant according to an N-shaped path to clean the hull.

[0007] Optionally, the motion mode includes a turning-in-place mode and a circular motion mode. In the turning-in-place mode, the following equation group can be obtained based on the motion of the robot: ; ; ; S =V R (t)t; The pose update formula in the turning-in-place mode can be obtained by arranging the equations, as shown in the following formula: ; In the formula, V L (t) is the speed of the left drive wheel, V R (t) is the speed of the right drive wheel, R1 is the turning radius, θ(t) is the turning angle, S(t) is the distance traveled by the hull cleaning robot, and d1 is the distance between the two drive wheels. In the circular motion mode, the following equation group can be obtained based on the motion of the robot: ; ; ; The pose update formula in the circular motion mode can be obtained by arranging the equations, as shown in the following formula: (COS ) - 1); sin ); ; ; In the formula, S L is the travel distance of the left drive wheel, S R is the travel distance of the right drive wheel, is the angle between the line connecting the robot center O1 and the turning center O2 and the initial position, is the turning radius of the right drive wheel, is the turning radius of the left drive wheel.

[0008] Optionally, the positioning system performs an iterative algorithm to correct the position coordinates of the target robot, and the iterative algorithm comprises: initializing a position (x0, y0) based on the previous cycle position (x1, y1) of the target robot, ); ); solving the position deviation by Taylor expansion and least square method, and solving the position deviation satisfying the following relationship: B; wherein, represents a position deviation vector, represents an x-axis position deviation component, represents a y-axis position deviation component, all represent measurable constant matrices; stopping iteration when , and outputting the corrected coordinate information after the iteration stops .

[0009] represents the x-axis coordinate of the robot in the coordinate axis after iteration, represents the y-axis coordinate of the robot in the coordinate axis after iteration, represents the initialization coordinate of the robot in the x-axis of the coordinate axis before iteration, represents the initialization coordinate of the robot in the y-axis of the coordinate axis before iteration.

[0010] Optionally, the seven-step movement comprises: S1, reading starting point position information and target point position information; S2, performing straight line movement from the starting point position to the target point position; S3, performing quarter-circle arc movement at the target point position to a first intermediate position; S4, performing quarter-circle arc movement from the first intermediate position to a second intermediate position; S5, performing straight line movement from the second intermediate position to a third intermediate position; S6, performing quarter-circle arc movement from the third intermediate position to a fourth intermediate position; S7, performing quarter-circle arc movement from the fourth intermediate position to the starting point position of the next seven-step movement.

[0011] In a second aspect, the embodiments of the present application provide a control system of a ship body cleaning robot, and the system comprises: a driving perception module: left and right incremental encoders are connected to left and right drive wheels respectively, and wheel speed and displacement are collected in real time;​​​​​ Laser positioning module: laser transmitter with rotating device communicates with laser receiver, constituting a pose correction system; Motion control module: receiving driving perception module and laser positioning module data, performing pose calculation and N-shaped path planning; Execution module: driving left and right drive wheels and driven wheels to realize steering and controlling the water outlet pipe to spray high-pressure water.

[0012] Optionally, in the laser positioning module, the laser transmitter and the four receivers constitute a planar positioning network, and the receivers are fixed on the hull wall surface in a rectangular layout.

[0013] Optionally, the motion control module has an iterative algorithm processor built-in, which is used to perform the least square position solution in claim 3.

[0014] Optionally, the driven wheels of the execution module are universal wheel structures, and constitute a three-point support system with the left and right drive wheels.

[0015] Beneficial effects: The control method of the ship body cleaning robot provided by the application can ensure continuous motion control by real-time pose calculation by an incremental encoder, suppresses accumulated error by periodic correction using a laser positioning system, controls position drift at a sub-centimeter level, breaks through the precision bottleneck of traditional pure encoder positioning, and uses the least square method to solve position deviation, combined with Taylor expansion linearization processing, to realize fast convergence in a complex wall surface environment; seven-step cyclic operation in each quadrant forms a continuous coverage trajectory, and the partition cleaning mode avoids global repositioning, improves the unit time operation area, and switches the in-place steering and circular motion as needed to adapt to the complex wall surface topological structure. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The flowchart of the control method of the ship body cleaning robot of the preferred embodiment of the application; Figure 2 The motion speed diagram of the ship body robot of the preferred embodiment of the application; Figure 3 The in-place steering diagram of the robot provided by the preferred embodiment of the application; Figure 4 The circular motion diagram of the robot provided by the preferred embodiment of the application; Figure 5 The principle diagram of the auxiliary mode of robot position determination provided by the preferred embodiment of the application; Figure 6 The running trajectory diagram of the robot cleaning control provided by the preferred embodiment of the application; Figure 7 The structure diagram of the control system of the ship body robot of the preferred embodiment of the application. DETAILED DESCRIPTION

[0017] The technical solutions of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0018] Unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the common meanings of the technical terms or scientific terms understood by those skilled in the art to which the present application belongs. The terms “first”, “second” and similar terms used in the present application do not represent any order, number or importance, but are only used to distinguish different components. Similarly, the terms “one” or “a” and similar terms do not represent a quantity limitation, but represent the existence of at least one. The terms “connected” or “connected” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “up”, “down”, “left”, “right” and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships are also changed accordingly.

[0019] Please refer to Figure 1 The control method of the ship body cleaning robot provided by the embodiments of the present application comprises the following steps: The first rotation speed of the left driving wheel is collected in real time through the left end incremental encoder, the second rotation speed of the right driving wheel is collected in real time through the right end incremental encoder, and the pose of the target robot is calculated in the motion mode based on the first rotation speed, the second rotation speed and the driving wheel distance between the left driving wheel and the right driving wheel. The positioning system is constructed by the laser emitter and the laser receiver, and the position coordinates of the target robot are corrected by the iterative algorithm using the positioning system. The ship body is divided into four quadrants, and the seven-step motion is repeatedly performed according to the N-shaped path in each quadrant to clean the ship body.

[0020] In the above embodiments, the position of the ship body cleaning robot is determined by combining the main and auxiliary methods, i.e. the main method of position determination and the auxiliary method of position determination are combined.

[0021] The main method of position determination is as follows: According to the working environment of the ship body cleaning robot, a plane rectangular coordinate system as shown in Figure 2 is established. The point O' is the position reference point (the center of the two driving wheels) of the ship body cleaning robot, the angle between the advancing direction of the ship body cleaning robot (i.e. the direction of the speed V(t)) and the X-axis of the coordinate system is θ(t). The coordinates of the ship body cleaning robot at any time are represented as [x(t), y(t), (t)].

[0022] The hull cleaning robot mainly involves two modes during operation: turning in place and moving along a circular arc.

[0023] When the hull cleaning robot turns in place, such as Figure 3 As shown, when one of the two drive wheels of the hull cleaning robot rotates clockwise and the other rotates counterclockwise, the driven wheel passively adjusts the direction of travel, which can enable the hull cleaning robot to turn around the center point O' of the two drive wheels. At this time, the x(t) and y(t) coordinate values ​​of the robot remain unchanged, while the θ(t) value changes.

[0024] V L (t) represents the rotational speed of the left drive wheel, in m / s, V R θ(t) is the rotational speed of the right drive wheel in m / s, R1 is the turning radius, θ(t) is the turning angle, S(t) is the distance traveled by the hull cleaning robot, and d1 is the distance between the two drive wheels. The resulting system of equations is:

[0025]

[0026]

[0027] S =V R (t)t Summarized as follows:

[0028] When the hull cleaning robot rotates in an arc, as... Figure 4 As shown, when the two drive wheels rotate in the same direction but at different speeds, i.e., V L (t), V R (t) When the directions are the same but the magnitudes are different. Figure 4 In the middle, V R (t) is greater than V L (t), the robot rotates in an arc to the left with O2 as the center.

[0029] exist Figure 4 In the diagram, let the initial position O1 of the hull cleaning robot be (0, 0, 0). The two drive wheels of the hull cleaning robot move at V... L (t), V R Traveling at speed (t), the distances traveled are S. L S R The coordinates of point O1 of the ship hull cleaning robot at any position are (x(t), y(t), The angle between the line connecting the center O1 of the hull cleaning robot to the turning center O2 and the initial position is... , resulting in the following system of equations:

[0030]

[0031]

[0032] Rearranging gives: (COS( ）-1） sin( ）

[0033]

[0034] Auxiliary method for robot position determination and iterative operation: As Figure 5 , the hull robot detects and identifies 4 laser receivers Pi(x i ,y i ), and the direction of the hull robot speed V(t) and the angle between the hull robot and the laser receiver is φ i . The following algorithm can be used to determine the position coordinates of the hull robot (x r,t , y r,t , r,t ). 1≤i≤4.

[0035] Position determination algorithm: Assuming the angle between the two adjacent laser receivers is i , let x5=x1, y5=y1, then: -

[0036] Let: ， ， ，

[0037] where (x , is the position of the hull cleaning robot at the previous position determination cycle. Thus, 1 and 2 are the Taylor expansion of f(x) at (x0, y0) is: , 1= + · · + · · +O( , ) Let = , = , then the above equation can be rearranged as: + · + · +O( , ) + · + · +O( , ) Neglecting the high-order infinitesimal term O( , ), we can get · + ·

[0038] where,

[0039]

[0040]

[0041] Thus, m equations can be listed and written as:

[0042] where,

[0043] ​

[0044] wherein, , a constant matrix. Thus, the least square method can be used to solve , B Let , =

[0045] Since A, B are related to (x, y), the iteration can be performed, and when , the iteration can be stopped. The position (x, y) of the hull robot can be determined by the following formula.

[0046] ,

[0047] Figure 5 In r,t is the attitude of the hull robot.

[0048] For the cleaning process of the robot: The hull cleaning robot cleaning control adopts a four-quadrant operation mode, and repeatedly adopts an N-shaped operation mode in each quadrant.

[0049] For the first quadrant, repeatedly adopt an N-shaped operation mode, and one N-shaped operation mode includes seven steps. The first step is to read the position coordinates of two points, position 1 and position 2, in the operation diagram of the hull cleaning robot cleaning control; the second step is that the hull cleaning robot runs straight from position 1 to position 2; the third step is that the hull cleaning robot runs through a quarter of a circular arc from position 2 to position 3; the fourth step is that the hull cleaning robot runs through a quarter of a circular arc from position 3 to position 4; the fifth step is that the hull cleaning robot runs straight from position 4 to position 5; the sixth step is that the hull cleaning robot runs through a quarter of a circular arc from position 5 to position 6; and the seventh step is that the hull cleaning robot runs through a quarter of a circular arc from position 6 to position 1. Figure 6 For the second quadrant, repeatedly adopt an N-shaped operation mode, and one N-shaped operation mode includes seven steps. The first step is to read the position coordinates of two points, position 1 and position 2, in the operation diagram of the hull cleaning robot cleaning control; the second step is that the hull cleaning robot runs straight from position 1 to position 2; the third step is that the hull cleaning robot runs through a quarter of a circular arc from position 2 to position 3; the fourth step is that the hull cleaning robot runs through a quarter of a circular arc from position 3 to position 4; the fifth step is that the hull cleaning robot runs straight from position 4 to position 5; the sixth step is that the hull cleaning robot runs through a quarter of a circular arc from position 5 to position 6; and the seventh step is that the hull cleaning robot runs through a quarter of a circular arc from position 6 to position 1. For the second quadrant, repeatedly adopt an N-shaped operation mode, and one N-shaped operation mode includes seven steps. The first step is to read the position coordinates of two points, position 1 and position 2, in the operation diagram of the hull cleaning robot cleaning control; the second step is that the hull cleaning robot runs straight from position 1 to position 2; the third step is that the hull cleaning robot runs through a quarter of a circular arc from position 2 to position 3; the fourth step is that the hull cleaning robot runs through a quarter of a circular arc from position 3 to position 4; the fifth step is that the hull cleaning robot runs straight from position 4 to position 5; the sixth step is that the hull cleaning robot runs through a quarter of a circular arc from position 5 to position 6; and the seventh step is that the hull cleaning robot runs through a quarter of a circular arc from position 6 to position 1. Figure 6 ​​​The diagram shows the coordinates of points 1 and 2 in the operation control of the hull cleaning robot. The second step involves the robot moving in a straight line from point 1 to point 2. The third step involves the robot moving from point 2 through a quarter-circle arc to point 3. The fourth step involves the robot moving from point 3 through a quarter-circle arc to point 4. The fifth step involves the robot moving in a straight line from point 4 to point 5. The sixth step involves the robot moving from point 5 through a quarter-circle arc to point 6. The seventh step involves the robot moving from point 6 through a quarter-circle arc back to point 1. For the third quadrant, the N-shaped approach is repeated, with each N-shaped approach consisting of seven steps. The first step is to read... Figure 6 The diagram shows the coordinates of points 1 and 2 in the operation control of the hull cleaning robot. The second step involves the robot moving in a straight line from point 1 to point 2. The third step involves the robot moving from point 2 through a quarter-circle arc to point 3. The fourth step involves the robot moving from point 3 through a quarter-circle arc to point 4. The fifth step involves the robot moving in a straight line from point 4 to point 5. The sixth step involves the robot moving from point 5 through a quarter-circle arc to point 6. The seventh step involves the robot moving from point 6 through a quarter-circle arc back to point 1. For the fourth quadrant, the N-shaped approach is repeated, with each N-shaped approach consisting of seven steps. The first step is to read... Figure 6 The diagram shows the coordinates of points 1 and 2 in the operation control of the hull cleaning robot. The second step involves the robot moving in a straight line from point 1 to point 2. The third step involves the robot moving from point 2 through a quarter-circle arc to point 3. The fourth step involves the robot moving from point 3 through a quarter-circle arc to point 4. The fifth step involves the robot moving in a straight line from point 4 to point 5. The sixth step involves the robot moving from point 5 through a quarter-circle arc to point 6. The seventh step involves the robot moving from point 6 through a quarter-circle arc back to point 1.

[0050] like Figure 7 As shown in the illustration, this application also provides a control system for a ship hull cleaning robot, the system comprising: Drive sensing module: Left and right incremental encoders are connected to the left and right drive wheels respectively to collect wheel speed and displacement in real time; Laser positioning module: A laser transmitter with a rotating device communicates with a laser receiver to form a posture correction system; Motion control module: Receives data from the drive sensing module and the laser positioning module, and performs pose calculation and N-shaped path planning; The execution module drives the left and right drive wheels and the driven wheel to realize steering, and controls the water outlet pipe to spray high-pressure water.

[0051] Optionally, in the laser positioning module, the laser emitter and the four receivers form a planar positioning network, and the receivers are fixed on the hull wall surface in a rectangular layout.

[0052] Optionally, the motion control module is provided with an iterative algorithm processor for performing the least square position solution in claim 3.

[0053] Optionally, the driven wheel of the execution module is a universal wheel structure, and forms a three-point support system with the left and right drive wheels.

[0054] The preferred embodiments of the present application are described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations without creative work based on the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the existing technology according to the concept of the present application shall be within the protection scope defined by the claims.

Claims

1. A control method of a hull cleaning robot, characterized in that, The method comprises the following steps: Real-time acquisition of the first rotation speed of the left drive wheel through the left end incremental encoder, real-time acquisition of the second rotation speed of the right drive wheel through the right end incremental encoder, and calculation of the pose of the target robot in the motion mode based on the first rotation speed, the second rotation speed and the drive wheel spacing between the left drive wheel and the right drive wheel; Construction of a positioning system and coordinate axes by a laser emitter and a laser receiver, and correction of the position coordinates of the target robot in the coordinate axes by the positioning system through an iterative algorithm; The hull is divided into four quadrants, and the seven-step motion is repeatedly performed in each quadrant according to the N-shaped path to clean the hull through the seven-step motion.

2. The control method of the hull cleaning robot according to claim 1, characterized in that, The motion mode comprises a spot turning mode and a circular arc motion mode. In the spot turning mode, the following equation group can be obtained based on the motion of the robot: ； ； ； S =V R (t) t; The pose updating formula in the spot turning mode can be obtained by arranging the equation, as shown in the following formula: ； wherein V L (t) is the rotational speed of the left drive wheel, V R (t) is the rotational speed of the right drive wheel, R1 is the turning radius, θ(t) is the turning angle, S(t) is the distance traveled by the hull cleaning robot, d1 is the distance between the two drive wheels, and t is the movement time of the hull cleaning robot. In the circular arc motion mode, the following equation group can be obtained based on the motion of the robot: ； ； ； The pose updating formula in the circular arc motion mode can be obtained by arranging the equation, as shown in the following formula: (COS( )-1); sin(θ) + cos(θ) = 1 ); ； ； In the formula, S L is the running distance of the left drive wheel, S R is the running distance of the right drive wheel, is the angle between the line connecting the robot center O1 and the turning center O2 and the initial position, is the turning radius of the right drive wheel, is the turning radius of the left drive wheel, x(t) is the x-axis coordinate of the hull cleaning robot on the hull wall surface, and y(t) is the y-axis coordinate of the hull cleaning robot on the hull wall surface.

3. The control method of the hull cleaning robot according to claim 1, characterized in that, The iterative algorithm for correcting the position coordinates of the target robot in the coordinate axes by the positioning system comprises: based on a previous cycle position of the target robot , ) initialize a position , ) The position deviation is solved by Taylor expansion and least square method, and the following relationship is solved: B； wherein represents a position deviation vector, and , A, B each represent a measurable constant matrix, represents an x-axis position deviation component, represents a y-axis position deviation component; When iteration is stopped, and the corrected coordinate information is output after the iteration is stopped , ; wherein, represents the coordinate of the robot in the x-axis of the coordinate axis after iteration, represents the coordinate of the robot in the y-axis of the coordinate axis after iteration, represents the initial coordinate of the robot in the x-axis of the coordinate axis before iteration, represents the initial coordinate of the robot in the y-axis of the coordinate axis before iteration.

4. The control method of the hull cleaning robot according to claim 1, characterized in that, The seven-step motion comprises: S1, reading the starting point position information and the target point position information; S2, performing straight line motion from the starting point position to the target point position; S3, performing quarter circular arc motion at the target point position to the first intermediate position; S4, performing quarter circular arc motion from the first intermediate position to the second intermediate position; S5, performing straight line motion from the second intermediate position to the third intermediate position; S6, performing quarter circular arc motion from the third intermediate position to the fourth intermediate position; S7, performing quarter circular arc motion from the fourth intermediate position to the starting point position of the next seven-step motion.

5. A control system for a hull cleaning robot, characterized in that The system comprises: A drive perception module: left and right incremental encoders are connected to the left and right drive wheels respectively to real-time acquire wheel speed and displacement; A laser positioning module: a laser emitter with a rotating device communicates with a laser receiver to form a pose correction system; A motion control module: receiving data from the drive perception module and the laser positioning module, performing pose calculation and N-shaped path planning; An execution module: driving the left and right drive wheels and the driven wheel to realize steering, and controlling the water outlet pipe to spray high-pressure water.

6. The control system of the hull cleaning robot according to claim 5, characterized in that, In the laser positioning module, the laser emitter and the four receivers form a planar positioning network, and the receivers are fixed on the hull wall surface in a rectangular layout.

7. The control system of claim 5, wherein, The motion control module is provided with an iterative algorithm processor for performing the least square position solution in claim 3.

8. The control system of the hull cleaning robot according to claim 5, characterized in that, The driven wheel of the execution module is a universal wheel structure, and forms a three-point support system with the left and right drive wheels.

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