A laser cleaning method and laser cleaning apparatus

Abstract

This invention belongs to the field of laser cleaning, and specifically relates to a laser cleaning method and a laser cleaning apparatus. For cleaning complex curved workpieces, this invention proposes a laser cleaning method that utilizes multiple range sensors that move synchronously with the laser cleaning head for focusing. The range sensors are arranged non-collinearly on the same mounting plane, and the distance between the range sensors and the focal plane of the laser cleaning head is [missing information]. L The distance measured by the distance sensor from the measuring point on the workpiece surface is l Fit all measuring points to the same measuring plane and calculate the distance. l average l 均 The angle between the normal direction of the measuring plane and the principal optical axis of the laser cleaning head is used to adjust the position and orientation of the laser cleaning head and the ranging sensor in real time, ensuring that the difference between the angle between the measuring plane and the calibration plane and the set angle is always less than 5° and 0.95. L ≤ l 均 ≤1.05 L By controlling the angle and distance between the measuring plane and the focal plane, the laser cleaning head is ensured to be at the optimal cleaning angle and optimal cleaning focal length.

Description

Technical Field

[0001] This invention belongs to the field of laser cleaning, and in particular relates to a laser cleaning method and a laser cleaning device. Background Technology

[0002] For planar workpieces, fixed automated equipment can be used to perform laser cleaning on their surfaces. This fixed automated equipment includes a three-axis industrial robot and a laser cleaning head mounted on the three-axis industrial robot as an end effector. The three-axis industrial robot can drive the laser cleaning head to move radially along the x, y, and z axes, thereby enabling the controller to control the laser cleaning head to move along a pre-set path. The three-axis industrial robot is also equipped with a single-point ranging sensor to measure the distance between the laser cleaning head and the workpiece surface. The data measured by the single-point ranging sensor can be used to adjust the distance between the laser cleaning head and the workpiece surface, thereby achieving focusing and ensuring that the focal point of the laser cleaning head is located on the workpiece surface, thus guaranteeing the cleaning effect.

[0003] When using the aforementioned fixed automated equipment, the controller drives the laser cleaning head to move along a set path to clean the entire surface of the flat workpiece.

[0004] For workpieces with flat surfaces, only the tilt angle of the laser cleaning head needs to be set in advance. For workpieces made of ordinary materials (such as iron), the reflectivity of the workpiece is low. In this case, it is best to place the laser cleaning head perpendicular to the workpiece surface for the best cleaning effect. For workpieces made of highly reflective materials (such as copper), the reflectivity of the workpiece is high. In this case, it is best to place the laser cleaning head at an 80° angle to the workpiece surface. On the one hand, this can ensure the cleaning effect, and on the other hand, it can effectively avoid damage to the laser cleaning head and other accessories caused by vertical laser reflection.

[0005] However, for complex curved workpieces (such as wind turbine blades, ship hulls, and aircraft skins), the aforementioned fixed automated equipment lacks the ability to adapt to the surface morphology of complex curved workpieces, resulting in insufficient precision in controlling the laser focus position, which affects cleaning efficiency and cleaning effect.

[0006] Currently, laser cleaning of complex curved workpieces is mostly carried out manually using a handheld laser gun, which results in poor cleaning effect and low cleaning efficiency. Summary of the Invention

[0007] The purpose of this invention is to provide a laser cleaning method to solve the technical problem that existing fixed automated equipment cannot be used to clean complex curved workpieces.

[0008] The present invention also aims to provide a laser cleaning device to solve the technical problem that existing fixed automated equipment cannot be used to clean complex curved workpieces.

[0009] To achieve the above objectives, the technical solution of the laser cleaning method provided by this invention is as follows:

[0010] A laser cleaning method utilizes base rangefinders that move synchronously with the laser cleaning head for focusing. At least three base rangefinders are arranged non-collinearly on the same mounting plane, which is perpendicular to the principal optical axis of the laser cleaning head. The ranging directions of the base rangefinders are parallel to the principal optical axis. The focal plane of the laser cleaning head is defined as the calibration plane, and the distance from the base rangefinders to the calibration plane is... L ;

[0011] During laser cleaning, each base distance sensor is used to measure the distance from different measuring points on the workpiece surface to the base distance sensor. l Fit all measuring points to the same measuring plane and calculate all distances. l average l 均 The three-dimensional position and tilt angle of the laser cleaning head and the base ranging sensor are adjusted in real time to ensure that the difference between the angle between the measuring plane and the calibration plane and the set angle is always less than 5°, and 0.95 L ≤ l 均 ≤1.05 L The angle is set according to the reflectivity of the workpiece.

[0012] Furthermore, the calibration surface has calibration points corresponding to the base ranging sensor, and the distance from the calibration point to the corresponding base ranging sensor is... L The angle between the measuring plane and the calibration plane is calculated based on the coordinates of the calibration point and the measuring point. During adjustment, the tilt angles of the laser cleaning head and the base distance sensor are first adjusted to ensure that the difference between the angle between the measuring plane and the calibration plane and the set angle is always less than 5°. Then, the laser cleaning head and the base distance sensor are translated to make the angle 0.95°. L ≤ l 均 ≤1.05 L .

[0013] Furthermore, along the extension direction of the main optical axis, the distance from the light beam at the laser cleaning head's output port to the center point of all basic sensors is defined as... H If the beam width at the laser cleaning head's output port is closer to the calibration surface than the center point of all the basic ranging sensors, then L = f + H If the center point of all the basic ranging sensors is closer to the calibration surface than the light beam area at the laser cleaning head's output port, then L = f - HIf the center point of all the basic ranging sensors is coplanar with the light beam area at the laser cleaning head's output port, then H =0, L = f+H In the formula, f This refers to the focal length of the laser cleaning head.

[0014] Furthermore, the basic ranging sensors are distributed at each vertex of the same polygon.

[0015] Furthermore, the number of laser cleaning heads is one, and the center point of the polygon is located on the main optical axis of the laser cleaning head; or, the number of laser cleaning heads is at least two, and the center point of the polygon is located on the central axis of the main optical axes of all laser cleaning heads.

[0016] Furthermore, there are three basic ranging sensors, and the three basic ranging sensors are located at the three vertices of an equilateral triangle.

[0017] Furthermore, multiple auxiliary extended ranging sensors are also installed on the mounting plane. The ranging direction of the auxiliary extended ranging sensors is parallel to the main optical axis. The auxiliary extended ranging sensors are arranged around the closed pattern connected to the basic ranging sensor to pre-determine the shape of the surface of the workpiece that needs to be cleaned next during laser cleaning by using the data measured by the auxiliary extended ranging sensors.

[0018] Furthermore, multiple auxiliary extended ranging sensors are also installed on the mounting plane. The ranging direction of the auxiliary extended ranging sensors is parallel to the main optical axis. The auxiliary extended ranging sensors are located on at least two adjacent sides of the top, right, bottom and left sides of the shape enclosed by the basic ranging sensors. On each side where the auxiliary extended ranging sensors are located, some auxiliary extended ranging sensors and some basic ranging sensors form a polygon that is the same as the shape enclosed by all the basic ranging sensors and coincides with one side of the shape enclosed by all the basic ranging sensors.

[0019] Furthermore, before laser cleaning, the laser cleaning head is moved along the outer contour of the workpiece in the x and z directions, and the outer contour of the workpiece is recorded. During cleaning, the laser cleaning head is controlled to perform an S-shaped reciprocating motion in the x and z directions to clean the entire surface within the outer contour. The y-position and tilt angle of the laser cleaning head are controlled to ensure that the angle between the measuring plane and the calibration plane is always less than 5°, and 0.95L ≤ l 均 ≤1.05L.

[0020] The beneficial effects of the laser cleaning method provided by this invention are as follows: This invention is an improved invention. The main difference between this invention and the prior art is that the prior art relies solely on the distance measured by a single ranging sensor for focusing, while this invention relies on at least three ranging sensors to determine the measuring plane, and focuses based on the angle and distance between the measuring plane and the focal plane.

[0021] At least three distance sensors are used to determine the measurement plane, which is then used to replace the actual surface of the workpiece. The angle between the measurement plane and the calibration plane (the focal plane of the laser cleaning head) is kept less than 5° from the set angle to ensure that the angle between the measurement plane and the focal plane is essentially the set angle. Furthermore, the average distance measured by all distance sensors is used to... l 均 Distance from the ranging sensor to the focal plane L The difference is no more than 5%, which can ensure that the focus is basically located on the surface of the workpiece and that the laser cleaning head is at the optimal cleaning focal length and the optimal cleaning angle.

[0022] Among them, utilizing L Used as a reference value, rather than utilizing the focal length of the laser cleaning head. f The reason for using this as a benchmark value is that, due to the certain dimensions of the laser cleaning head and the base ranging sensor, the actual distance from the base ranging sensor to the calibration surface is not equal to... f , Introduction L It can make focusing more precise.

[0023] The reason for setting the angle difference to always be less than 5° is that when the angle difference is greater than 5°, the perpendicularity between the laser and the workpiece surface is poor, resulting in a poor laser cleaning effect; similarly, setting it to 0.95... L ≤ l 均 ≤1.05 L The reason is: l 均 and L When the difference is greater than 5%, the laser cannot be well focused on the workpiece surface, resulting in poor laser cleaning effect.

[0024] To achieve the above objectives, the technical solution of the laser cleaning device provided by the present invention is as follows:

[0025] A laser cleaning apparatus includes a multi-axis industrial robot and a laser cleaning head mounted on the multi-axis robot as an end effector. The laser cleaning head is equipped with distance sensors that move synchronously with the laser cleaning head and are used for focusing. There are at least three distance sensors, which are arranged non-collinearly on the same mounting plane of the multi-axis industrial robot. The mounting plane is perpendicular to the main optical axis of the laser cleaning head, and the distance measuring direction of the distance sensors is parallel to the main optical axis. The multi-axis industrial robot is used to synchronously adjust the three-dimensional coordinates and tilt angles of the laser cleaning head and the distance sensors to achieve the following laser cleaning method:

[0026] Focusing is achieved using base rangefinders that move synchronously with the laser cleaning head. At least three base rangefinders are arranged non-collinearly on the same mounting plane, which is perpendicular to the principal optical axis of the laser cleaning head. The ranging direction of the base rangefinders is parallel to the principal optical axis. The focal plane of the laser cleaning head is defined as the calibration plane, and the distance from the base rangefinders to the calibration plane is... L ;

[0027] During laser cleaning, each base distance sensor is used to measure the distance from different measuring points on the workpiece surface to the base distance sensor. l Fit all measuring points to the same measuring plane and calculate all distances. l average l 均 The three-dimensional position and tilt angle of the laser cleaning head and the base ranging sensor are adjusted in real time to ensure that the difference between the angle between the measuring plane and the calibration plane and the set angle is always less than 5°, and 0.95 L ≤ l 均 ≤1.05 L The angle is set according to the reflectivity of the workpiece.

[0028] Furthermore, the calibration surface has calibration points corresponding to the base ranging sensor, and the distance from the calibration point to the corresponding base ranging sensor is... L The angle between the measuring plane and the calibration plane is calculated based on the coordinates of the calibration point and the measuring point. During adjustment, the tilt angles of the laser cleaning head and the base distance sensor are first adjusted to ensure that the difference between the angle between the measuring plane and the calibration plane and the set angle is always less than 5°. Then, the laser cleaning head and the base distance sensor are translated to make the angle 0.95°. L ≤ l 均 ≤1.05 L .

[0029] Furthermore, along the extension direction of the main optical axis, the distance from the light beam at the laser cleaning head's output port to the center point of all basic sensors is defined as... HIf the beam width at the laser cleaning head's output port is closer to the calibration surface than the center point of all the basic ranging sensors, then L = f + H If the center point of all the basic ranging sensors is closer to the calibration surface than the light beam area at the laser cleaning head's output port, then L = f - H If the center point of all the basic ranging sensors is coplanar with the light beam area at the laser cleaning head's output port, then H =0, L = f+H In the formula, f This refers to the focal length of the laser cleaning head.

[0030] Furthermore, the basic ranging sensors are distributed at each vertex of the same polygon.

[0031] Furthermore, the number of laser cleaning heads is one, and the center point of the polygon is located on the main optical axis of the laser cleaning head; or, the number of laser cleaning heads is at least two, and the center point of the polygon is located on the central axis of the main optical axes of all laser cleaning heads.

[0032] Furthermore, there are three basic ranging sensors, and the three basic ranging sensors are located at the three vertices of an equilateral triangle.

[0033] Furthermore, multiple auxiliary extended ranging sensors are also installed on the mounting plane. The ranging direction of the auxiliary extended ranging sensors is parallel to the main optical axis. The auxiliary extended ranging sensors are arranged around the closed pattern connected to the basic ranging sensor to pre-determine the shape of the surface of the workpiece that needs to be cleaned next during laser cleaning by using the data measured by the auxiliary extended ranging sensors.

[0034] Furthermore, multiple auxiliary extended ranging sensors are also installed on the mounting plane. The ranging direction of the auxiliary extended ranging sensors is parallel to the main optical axis. The auxiliary extended ranging sensors are located on at least two adjacent sides of the top, right, bottom and left sides of the shape enclosed by the basic ranging sensors. On each side where the auxiliary extended ranging sensors are located, some auxiliary extended ranging sensors and some basic ranging sensors form a polygon that is the same as the shape enclosed by all the basic ranging sensors and coincides with one side of the shape enclosed by all the basic ranging sensors.

[0035] Furthermore, before laser cleaning, the laser cleaning head is moved along the outer contour of the workpiece in the x and z directions, and the outer contour of the workpiece is recorded. During cleaning, the laser cleaning head is controlled to perform an S-shaped reciprocating motion in the x and z directions to clean the entire surface within the outer contour. The y-position and tilt angle of the laser cleaning head are controlled to ensure that the angle between the measuring plane and the calibration plane is always less than 5°, and 0.95L ≤ l 均 ≤1.05L.

[0036] The beneficial effects of the laser cleaning device provided by this invention are as follows: This invention is an improved invention. The main difference between this invention and the prior art is that the prior art relies solely on the distance measured by a single ranging sensor for focusing, while this invention relies on at least three ranging sensors to determine the measuring plane, and focuses based on the angle and distance between the measuring plane and the focal plane.

[0037] At least three distance sensors are used to determine the measurement plane, which is then used to replace the actual surface of the workpiece. The angle between the measurement plane and the calibration plane (the focal plane of the laser cleaning head) is kept less than 5° from the set angle to ensure that the angle between the measurement plane and the focal plane is essentially the set angle. Furthermore, the average distance measured by all distance sensors is used to... l 均 Distance from the ranging sensor to the focal plane L The difference is no more than 5%, which can ensure that the focus is basically located on the surface of the workpiece and that the laser cleaning head is at the optimal cleaning focal length and the optimal cleaning angle.

[0038] Among them, utilizing L Used as a reference value, rather than utilizing the focal length of the laser cleaning head. f The reason for using this as a benchmark value is that, due to the certain dimensions of the laser cleaning head and the base ranging sensor, the actual distance from the base ranging sensor to the calibration surface is not equal to... f , Introduction L It can make focusing more precise.

[0039] The reason for setting the angle difference to always be less than 5° is that when the angle difference is greater than 5°, the perpendicularity between the laser and the workpiece surface is poor, resulting in a poor laser cleaning effect; similarly, setting it to 0.95... L ≤ l 均 ≤1.05 L The reason is: l 均 and L When the difference is greater than 5%, the laser cannot be well focused on the workpiece surface, resulting in poor laser cleaning effect. Attached Figure Description

[0040] Figure 1 A schematic diagram of the laser cleaning device from one angle (air and water pipes omitted);

[0041] Figure 2 This is a schematic diagram of the laser cleaning device from another angle;

[0042] Figure 3 for Figure 1 A schematic diagram of the structure of the laser cleaning head and the basic ranging sensor (the auxiliary extended ranging sensor is not shown).

[0043] Figure 4 A schematic diagram for determining the outer contour of a workpiece;

[0044] Figure 5 This is a path diagram of the laser cleaning head performing S-shaped reciprocating motion along the x and z directions during laser cleaning.

[0045] Figure 6 A schematic diagram of focusing using a basic rangefinder sensor (sensor reference plane not shown).

[0046] Figure 7 This is a schematic diagram of the focusing process using a basic rangefinder sensor.

[0047] Figure 8 This is a schematic diagram of laser cleaning using a basic ranging sensor and an auxiliary extended ranging sensor.

[0048] Figure 9 This is a schematic diagram of another laser cleaning process using a basic range sensor and an auxiliary extended range sensor.

[0049] Figure 10 This is a schematic diagram of the structure when the offset distance between the laser beam area of ​​the laser cleaning head and the center point of the base ranging sensor is H.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Support leg; 2. Linear guide rail; 3. Rack; 4. Gear; 5. X-axis servo motor; 6. Moving stage; 7. Motor driver; 8. Buffer block; 9. Laser control box; 10. Tank chain; 11. Support frame; 12. Column; 13. Water chiller; 14. Water chiller control box; 15. Tri-color light; 16. Z-axis servo motor; 17. Cantilever assembly; 18. Y-axis servo motor; 19. Laser; 20. Base extension connecting block; 21. First safety switch; 22. Water pipe; 23. Air pipe; 24. Display screen; 25. Second safety switch; 26. Compressed air pump; 27. V-axis servo motor; 281. First turntable; 282. Second turntable; 29. ​​U-axis servo motor; 30. Laser cleaning head; 31. Mounting plane; 32. Basic distance sensor. Detailed Implementation

[0052] To address the problems in the background art, the core inventive concept of this invention is as follows: At least three ranging sensors are used to determine the measuring plane, which is then used to replace the actual surface of the workpiece. By ensuring that the difference between the angle between the measuring plane and the calibration plane (the focal plane of the laser cleaning head) and the set angle is always less than 5°, the angle between the measuring plane and the focal plane is essentially the set angle. Based on this, the average distance measured by the ranging sensors is... l 均 Distance from the ranging sensor to the focal plane L The difference is no greater than 5%, ensuring that the angle between the measuring plane and the focal plane is basically the set angle, thereby ensuring that the laser cleaning head is at the optimal cleaning focal length and optimal cleaning angle. Among these, utilizing... L Used as a reference value, rather than utilizing the focal length of the laser cleaning head. f The reason for using this as a benchmark value is that, due to the certain dimensions of the laser cleaning head and the base ranging sensor, the actual distance from the base ranging sensor to the calibration surface is not equal to... f , Introduction L It can make focusing more precise.

[0053] The reason for setting the angle difference to always be less than 5° is that when the angle difference is greater than 5°, the perpendicularity between the laser and the workpiece surface is poor, resulting in a poor laser cleaning effect; similarly, setting it to 0.95... L ≤ l 均 ≤1.05 L The reason is: l 均 and L When the difference is greater than 5%, the laser cannot be well focused on the workpiece surface, resulting in poor laser cleaning effect.

[0054] The present invention will be further described in detail below with reference to the embodiments.

[0055] Examples of laser cleaning methods are as follows.

[0056] Reference Figures 1-9 As shown, in a basic embodiment, the laser cleaning method is as follows: focusing is performed using a base ranging sensor 32 that moves synchronously with the laser cleaning head 30. Simultaneously, the base ranging sensor 32 has at least three ( Figures 6-8 Specifically, there are three sensors, namely range sensor a, range sensor b, and range sensor c, all mounted on the same plane 31 (i.e., Figure 6 The sensors are arranged non-collinearly on the reference plane of the laser cleaning head 30. The mounting plane 31 is perpendicular to the principal optical axis of the laser cleaning head 30, and the ranging direction of the basic ranging sensor 32 is parallel to the principal optical axis. The focal plane of the laser cleaning head 30 is defined as the calibration plane (i.e., the reference plane of the laser cleaning head 30). Figure 6 The distance between the calibration surface (set in the calibration plane) and the base ranging sensor 32 is... L ;

[0057] During laser cleaning, each base distance sensor 32 is used to measure the distance from different measuring points on the workpiece surface to the base distance sensor 32. l Fit all measuring points to the same measuring plane (i.e. Figure 6 Within the actual measurement surface (in the diagram), calculate all distances. l average l 均 The three-dimensional position and tilt angle of the laser cleaning head 30 and the base ranging sensor 32 are adjusted in real time to ensure that the difference between the angle between the measuring plane and the calibration plane and the set angle is always less than 5° and 0.95. L ≤ l 均 ≤1.05 L .

[0058] The principal optical axis refers to the straight line connecting the two focal points. The focal plane is perpendicular to the principal optical axis, and the focal point lies on the focal plane. The set angle depends on the reflectivity of the workpiece. For workpieces made of common materials (such as iron), the reflectivity is low. In this case, the laser cleaning head 30 is preferably perpendicular to the workpiece surface (corresponding to a set angle of 0°) for optimal cleaning effect. For workpieces made of highly reflective materials (such as copper), the reflectivity is high. In this case, the laser cleaning head 30 is preferably at an 80° angle to the workpiece surface (corresponding to a set angle of 10°). This ensures cleaning effect while effectively preventing damage to the laser cleaning head 30 and other accessories caused by perpendicular laser reflection. Of course, depending on the actual reflectivity of the workpiece (mainly determined by the material), those skilled in the art can also set the set angle to other angles such as 5°. The following explanation uses a set angle of 0° as an example.

[0059] like Figures 6-7 As shown, when the measuring plane (i.e. Figure 6 The actual measurement surface and the calibration surface (i.e.) Figure 6 When the angle between the measurement plane and the calibration plane is always less than 5°, it can be considered that the measurement plane and the calibration plane are basically parallel. In this case, if... Figures 7-8 As shown, the angle between the principal axis of the laser and the normal to the measuring plane is less than 5°. This means the principal axis of the laser is essentially parallel to the normal to the measuring plane, and the laser is essentially perpendicular to the measuring plane, ensuring the laser cleaning head 30 is at the optimal cleaning angle. The reason for setting the angle to always be less than 5° is that when the angle is greater than 5°, the perpendicularity between the laser and the workpiece surface is poor, resulting in a poorer laser cleaning effect.

[0060] like Figure 6As shown, under the premise that the angle between the measuring plane and the calibration plane is always less than 5°, when 0.95 L ≤ l 均 ≤1.05 L When, the measurement plane (i.e.) can be considered as Figure 6 The actual measurement surface and the calibration surface (i.e.) Figure 6 The calibration plane is basically aligned with the laser. At this time, it can be assumed that the focal point of the laser (with a certain depth of focus) is basically on the measurement plane to ensure that the laser cleaning head 30 is at the optimal cleaning focal length.

[0061] Among them, utilizing L Used as a reference value, rather than utilizing the focal length of the laser cleaning head 30. f The reason for using this as a reference value is that, since the laser cleaning head 30 and the base ranging sensor 32 have certain dimensions, the actual distance between the base ranging sensor 32 and the calibration surface is not equal to... f , Introduction L It can make focusing more precise.

[0062] like Figure 3 and Figure 10 As shown, in the direction of extension of the main optical axis, the beam width at the output port of the laser cleaning head 30 (i.e., Figure 10 The laser cleaning head beam area is compared to the center point of all the basic ranging sensors 32 (i.e., Figure 10 The center point of the basic ranging sensor group (all basic ranging sensors 32 together constitute the basic ranging sensor group) is closer to the calibration surface. The distance from the light beam at the output port of the laser cleaning head 30 to the center point of all basic sensors 32 is... H ,but L = f + H In other embodiments, if the center point of all the base ranging sensors 32 is closer to the calibration surface than the light beam area at the light outlet of the laser cleaning head 30, then L = f - H If the center point of all the basic ranging sensors 32 is coplanar with the light beam area at the light outlet of the laser cleaning head 30, then H =0, L = f+H By introducing an H value for adjustment, the center point of all the base range sensors 32 and the light beam at the light outlet of the laser cleaning head 30 can be considered to be on the same plane, thereby eliminating the influence of the installation position and size of the base range sensors 32 and the laser cleaning head 30, and better ensuring that the laser cleaning head 30 is at the optimal cleaning focal length.

[0063] Among them, 0.95 is set. L ≤l 均 ≤1.05 L The reason is: when l 均 and L When the difference is greater than 5%, the laser cannot be well focused on the workpiece surface, resulting in poor laser cleaning effect.

[0064] Therefore, by adjusting the angle between the measuring plane and the calibration plane to always be less than 5°, and 0.95 L ≤ l 均 ≤1.05 L This effectively ensures that the laser cleaning head 30 is at the optimal cleaning angle and focal length, adapting to complex curved workpieces (e.g., Figures 7-8 The workpiece shown in the image.

[0065] Three non-collinear points define a plane, so the number of basic ranging sensors 32 can be three, four or more, and the basic ranging sensors 32 only need not be distributed on the same straight line. Those skilled in the art can set the position of the basic ranging sensors 32 according to actual needs.

[0066] In this invention, the calibration surface has calibration points corresponding to the base ranging sensor 32 [coordinates a3(x7, y7, z7), b3(x8, y8, z8), c3(x9, y9, z9)], and the distance from the calibration point to the corresponding base ranging sensor 32 [coordinates a1(x1, y1, z1), b1(x2, y2, z2), c1(x3, y3, z3)] is... L The angle between the measuring plane and the calibration plane is calculated based on the coordinates of the calibration point and the coordinates of the measuring point [coordinates are a2(x4, y4, z4), b2(x5, y5, z5), c2(x6, y6, z6)]. During adjustment, the tilt angles of the laser cleaning head 30 and the base distance sensor 32 are first adjusted to ensure that the difference between the angle between the measuring plane and the calibration plane and the set angle is always less than 5°. Then, the laser cleaning head 30 and the base distance sensor 32 are translated to make the angle 0.95° smaller than the set angle. L ≤ l 均 ≤1.05 L In this control method, the tilt angle and focusing distance are adjusted separately (the focusing distance is equal to...). l 均 The computational load was relatively small during both adjustments.

[0067] In other embodiments, the tilt angle and focus distance can be adjusted simultaneously to improve the adjustment rate.

[0068] In a preferred embodiment, the basic ranging sensors 32 are distributed at the vertices of the same regular polygon. At this time, the distances from each basic ranging sensor 32 to the center point of the corresponding regular polygon are equal. Therefore, the weights of the data measured by each basic ranging sensor 32 are equal, and thus the average value obtained l 均 is closer to the actual distance between the sensor reference plane (i.e., the mounting plane 31) and the workpiece surface (replaced by the measurement plane), so that the coincidence degree between the focal plane and the workpiece surface is better, improving the cleaning effect.

[0069] Refer to Figure 3 and Figures 6-8 As shown, the regular polygon can be an equilateral triangle. Of course, according to the number of basic ranging sensors 32, the regular polygon can also be a square, a regular pentagon, etc. Of course, the basic ranging sensors 32 can also be distributed at the vertices of other polygons that are not regular polygons.

[0070] After determining that the focal plane coincides with the measurement plane, theoretically, regardless of the relative position between the laser cleaning head 30 and the basic ranging sensors 32, the focal point of the laser cleaning head 30 falls on the measurement plane.

[0071] However, in the present invention, since the workpiece surface is actually a complex curved surface, when the relative positions between the laser cleaning head 30 and the basic ranging sensors 32 are different, the positions where the laser emitted by the laser cleaning head 30 hits the workpiece surface are different. Therefore, the curved surfaces actually hit by the laser are different.

[0072] To reduce the deviation between the curved surface hit by the laser and the measurement plane fitted according to the basic ranging sensors 32, the following two preferred embodiments are proposed in the present invention.

[0073] One is that the number of laser cleaning heads 30 is one, and the center point of the regular polygon is located on the main optical axis of the laser cleaning head 30, that is, the distances from each basic ranging sensor 32 to the main optical axis are equal. At this time, the deviation between the curved surface hit by the laser and the measurement plane is the smallest.

[0074] [[ID=二十五]]The other is that the number of laser cleaning heads 30 is at least two, and the center point of the regular polygon is located on the central axis of the main optical axes of all laser cleaning heads 30. In this embodiment, while ensuring that the deviation between the curved surface hit by the laser and the measurement plane is relatively small, the number of laser cleaning heads 30 is relatively large, and the area cleaned in a single time is relatively large, which is beneficial to improving the cleaning efficiency.

[0075] The number of laser cleaning heads 30 can be two, three or more. Those skilled in the art can balance the number of laser cleaning heads 30 and the number of basic ranging sensors 32 to improve the cleaning efficiency while meeting the cleaning quality requirements.

[0076] Refer to Figures 1-3 As shown, in a preferred embodiment, when there are three basic ranging sensors 32, there are two laser cleaning heads 30, and the center point of the equilateral triangle is located on the central axis of the main optical axis of all laser cleaning heads 30. In this case, on the one hand, the number of laser cleaning heads 30 is relatively large, and the area cleaned in a single operation is large, which is beneficial to improving cleaning efficiency; on the other hand, the number of laser cleaning heads 30 is not excessive, and the deviation between the curved surface hit by the laser and the measurement plane is small, which meets the cleaning quality requirements.

[0077] In the above embodiments, reference is made to Figures 1-7 As shown, focusing is accomplished solely by the basic range sensor 32.

[0078] In other embodiments, refer to Figures 7-8 As shown, multiple auxiliary extended ranging sensors are also installed on the mounting plane 31. The auxiliary extended ranging sensors are arranged around the closed pattern connected to the basic ranging sensor 32 to pre-determine the shape of the surface of the workpiece that needs to be cleaned next by using the data measured by the auxiliary extended ranging sensors during laser cleaning.

[0079] exist Figure 8 There are seven auxiliary rangefinder sensors, namely rangefinder d, rangefinder e, rangefinder f, rangefinder g, and rangefinder g.

[0080] The relative position between the laser cleaning head 30 and the workpiece surface can be initially determined by the auxiliary extended ranging sensor, and the relative position between the laser cleaning head 30 and the workpiece surface can be accurately determined by the basic ranging sensor 32, thereby achieving efficient laser cleaning of complex curved surfaces.

[0081] In this method, the surface to be cleaned is divided into multiple patches in real time, and spatial analysis is performed on each patch to obtain the normal direction of each patch. The position and orientation of the laser cleaning head 30 are then adjusted based on the obtained results.

[0082] Reference Figure 7 As shown, ranging sensors a, b, and c are all basic ranging sensors 32. These three sensors measure the spatial coordinates A0.0, A0.1, and A0.2 of three corners of a surface. Through spatial analytical geometry calculations, the normal direction of the surface can be calculated, and thus the angle between the principal optical axis of the laser cleaning head 30 and the normal of the surface can be determined. By adjusting the three-dimensional position of the laser cleaning head 30 in the x, y, and z directions and the tilt angles in the u and v directions, the laser can be directed to the curved surface at a suitable angle.

[0083] The auxiliary extended range sensor can measure the spatial coordinates of points A1.0, A1.1, A1.2, A2.0, A2.1, and A2.2, and calculate the normal direction of the corresponding surface patches. Through data analysis and stitching, the shape of the surface within the scanning range can be obtained, and the movement path can be automatically planned based on the known surface shape.

[0084] In other embodiments, refer to Figure 9 As shown, the auxiliary extended ranging sensor is located on at least two adjacent sides of the top, right, bottom, and left sides of the pattern enclosed by the basic ranging sensor 32. Figure 9 (middle is the right side and bottom side), on each side where the auxiliary extended ranging sensor is located ( Figure 9 The middle part (right side and bottom side) and part of the auxiliary extended ranging sensors and the basic ranging sensors 32 form a polygon that is the same as the shape enclosed by all the basic ranging sensors 32 and coincides with one side of the shape enclosed by all the basic ranging sensors 32, preferably a regular polygon.

[0085] exist Figure 9 In the system, there are four auxiliary rangefinder sensors, namely rangefinder d, rangefinder e, rangefinder f, and rangefinder g.

[0086] During laser cleaning, it is necessary to control the laser cleaning head 30 to clean the entire surface of the workpiece. In one embodiment, such as... Figure 4 As shown, before laser cleaning, the laser cleaning head 30 is moved along the outer contour of the workpiece in the x and z directions, and the outer contour of the workpiece (A1-A2-A3-A4-An-B1-B2-B3-B4-Bn-A1) is recorded. During cleaning, as shown... Figure 5 As shown, the laser cleaning head 30 is controlled to perform an S-shaped reciprocating motion along the x and z directions to clean the entire surface within the outer contour. The y-position and tilt angle of the laser cleaning head 30 are also controlled to ensure that the angle between the measuring plane and the calibration plane is always less than 5°, and 0.95L ≤ l 均 ≤1.05L.

[0087] In other embodiments, the outline of the entire surface of the workpiece can be determined by a vision sensor, and the laser cleaning head 30 can be controlled to clean the entire surface of the workpiece based on the data from the vision sensor. See also Chinese invention patent application CN117619823A, published on March 1, 2024, or Chinese invention patent application CN117443853A, published on January 26, 2024.

[0088] In other embodiments, if the specific three-dimensional model of the workpiece is known, the three-dimensional model can be directly imported into the control system (including the CPU), and the control system can automatically calculate the cleaning path.

[0089] An example of a laser cleaning device is shown below.

[0090] The laser cleaning device in this invention is used to implement the laser cleaning method in this invention.

[0091] like Figures 1-3 As shown, in a basic embodiment, the laser cleaning device includes a multi-axis industrial robot and a laser cleaning head 30 mounted on the multi-axis robot as an end effector. The laser cleaning head 30 is equipped with a ranging sensor (at least including a basic ranging sensor 32, which may include an auxiliary extended ranging sensor, or may not include an auxiliary extended ranging sensor) that moves synchronously with the laser cleaning head 30 for focusing. There are at least three ranging sensors, which are arranged non-collinearly on the same mounting plane 31 of the multi-axis industrial robot. The mounting plane 31 is perpendicular to the main optical axis of the laser cleaning head 30. The multi-axis industrial robot is used to synchronously adjust the three-dimensional coordinates and tilt angles of the laser cleaning head 30 and the ranging sensors.

[0092] The multi-axis industrial robot can be a five-axis robot including x, y, z, u, and v axes, or a six-axis robot including a w axis. The key requirement is that the laser cleaning head 30 can scan the entire surface of the object to be cleaned and that the cleaning angle of the laser cleaning head 30 can be adjusted. The multi-axis industrial robot can be purchased as a complete unit.

[0093] To facilitate understanding by those skilled in the art, a specific multi-axis industrial robot is provided below.

[0094] like Figures 1-3 As shown, the multi-axis industrial robot includes a base, on which a movable stage 6 is mounted, movable along the x-axis. The movable stage 6 is equipped with a laser 19 for generating laser light for the laser cleaning head 30 and a column 12 extending along the z-axis. A cantilever assembly 17, movable along the z-axis, is connected to the column 12. The cantilever assembly 17 includes a direct drive mechanism for movement along the y-axis. The output end of the direct drive mechanism is connected to a first turntable 281 rotating along the v-axis. A second turntable 282 rotating along the u-axis is connected to the first turntable 281. The second turntable 282 has the aforementioned mounting plane 31, and the laser cleaning head 30 is also mounted on the mounting plane 31. The movable stage 6, cantilever assembly 17, direct drive mechanism, first turntable 281, and second turntable 282 are all equipped with corresponding servo motors.

[0095] The base includes a linear guide rail 2 and support legs 1. A rack 3 extending along the x-direction is mounted on the linear guide rail 2. A gear 4 meshes with the rack 3 on the movable stage 6, and the movable stage 6 is movably engaged with the linear guide rail 2 along the x-direction. The movable stage 6 is equipped with an x-axis servo motor 5, which drives the gear 4 to rotate, thereby moving the movable stage 6 along the x-direction. A baffle is also installed on the base to prevent the movable stage 6 from detaching from the linear guide rail 2 along the x-direction. The baffle has buffer rubber blocks 8 to cushion collisions between the baffle and the movable stage 6. Additionally, the base has a base extension connecting block 20 to extend the base's x-direction length.

[0096] The mobile platform 6 is also equipped with a laser 19 for generating laser light, a laser control box 9, and a motor driver 7. The column 12 is equipped with a support frame 11 to strengthen the structure of the column 12. The laser control box 9 includes a first safety switch 21.

[0097] The cantilever assembly 17 is equipped with a z-axis servo motor 16 mounted on the column 12, which can drive the cantilever assembly 17 to rise and fall.

[0098] The direct drive mechanism is equipped with a y-axis servo motor 18, which is used to drive the y-axis slide in the direct drive mechanism to move along the y-axis.

[0099] A v-axis servo motor 27 is mounted on the y-axis slide, and the output end of the v-axis servo motor 27 is connected to the first turntable 281. A u-axis servo motor 29 is mounted on the first turntable 281, and the output end of the u-axis servo motor 29 is connected to the second turntable 282. The second turntable 282 has the aforementioned mounting plane 31, and the ranging sensor and the laser cleaning head 30 are both mounted on the mounting plane 31.

[0100] The laser 19 generates a lot of heat during operation and needs to be shut down for heat dissipation after a period of operation. To ensure that the laser 19 can operate continuously, it needs to be equipped with an air-cooled or water-cooled heat dissipation mechanism.

[0101] exist Figures 1-3 In the illustrated embodiment, the laser 19 is equipped with a water-cooling heat dissipation mechanism, which includes a water chiller 13. The water chiller 13 is equipped with water-cooling pipes for cooling the laser 19 and the laser cleaning head 30. The portion of the water-cooling pipe used to cool the laser 19 is located upstream of the portion used to cool the laser cleaning head 30. The water chiller 13 is equipped with a water chiller control box 14, which is equipped with a tri-color light 15 to facilitate operators in judging the working status of the laser cleaning device. The water-cooling pipes include water pipes 22, a portion of which is protected by a tank chain 10 to ensure that the water pipes 22 are not damaged when moving with the laser cleaning head 30. The water chiller control box 14 includes a display screen 24 and a second safety switch 25.

[0102] Dust removal is required during laser cleaning. Figures 1-3 In the illustrated embodiment, the laser cleaning apparatus further includes a gas compressor comprising a compressed air pump 26 and an air duct extending to the laser cleaning head 30 for gas dust removal during laser cleaning. At least a portion of the air duct is formed by an air pipe 23, which is also equipped with a tank chain 10 for protection.

[0103] In other embodiments, the laser cleaning apparatus may also include a negative pressure suction dust removal device (or vacuum cleaner), the air inlet of which is located at the laser cleaning head 30, and the air inlet is connected to a negative pressure generator through a pipe to remove dust by suction.

[0104] The following describes the specific operation process of implementing the laser cleaning method of the present invention using the laser cleaning device of the present invention.

[0105] Step S1: Before powering on, add purified water to the water tank of the water chiller 13 (for environments below 0℃, add special antifreeze). Power on the machine and turn on the emergency stop switches of the two control boxes. The water chiller 13 starts working, and the water flows through the water pipe 22 and the tank chain 10 to the laser 19 and the cleaning head. The low-temperature water flows into the laser machine for circulation and cooling. The room-temperature water flows through the laser cleaning head 30 to maintain the normal operating temperature. After the system loads, it outputs an I / O signal to the motor driver 7 after a 3-second delay. After receiving the signal, the controller releases the magnetic brake on the motor.

[0106] Step S2: Place the workpiece to be cleaned within the effective cleaning range, 1-1.5 meters away from the laser cleaning head and the guide rail, with the length not exceeding the effective range of the guide rail's travel.

[0107] Step S3: After the system is ready, click the configuration button on the wireless handwheel to pair the handwheel with the wireless receiver within the system. The integrated system communicates with the motor controller via EtherCAT through a network cable to synchronize the forward and reverse rotation and speed of the five motors within the device. The motors use absolute encoders to ensure that the position coordinates are not lost in the event of a power outage.

[0108] Step S4: After all prerequisites are prepared, based on the workpiece size, select the axis number of the wireless handwheel and output a specified pulse signal. The wireless receiver receives the signal and transmits it to the control system. Upon receiving the corresponding pulse signal, the control system instructs the corresponding motor to run along the specified track (the X-axis motor is driven by gear 4 and rack 3, causing the laser cleaning head 30 to move along the linear guide rail 2; the Y-axis uses a motor to control the ball screw and slider to move the laser cleaning head 30 back and forth; the Z-axis uses a motor, gear 4, rack 3, and linear guide rail 2 to control the lifting and lowering of the laser cleaning head 30).

[0109] Step S5: The system controls the scanning width by controlling the deflection amplitude of the internal galvanometer motor of the laser cleaning head 30 via the XY2-100 protocol. The single system synchronously outputs two sets of signals to ensure the coordination and synchronization of the two laser cleaning heads 30. The output power of the laser 19 is controlled via analog signals, and the duty cycle and frequency of the laser output are controlled via a PWM interface.

[0110] Step S6, as follows Figure 4 As shown, based on the workpiece dimensions, the laser cleaning head 30 is moved to the upper left corner of the surface to be cleaned via a handwheel. The coordinates A1 are recorded in the control system. The head then moves along the upper edge of the workpiece's outline, simultaneously recording the coordinates of turning points A2, A3, A4…An. Upon reaching the lower right corner of the workpiece, the coordinates B1 are recorded. The head then moves along the lower edge, simultaneously recording the coordinates of turning points B2, B3, B4…Bn. The system uses the recorded coordinates to calculate the workpiece's cleaning shape and boundary.

[0111] Step S7, as follows Figure 5 As shown, the system calculates the S-shaped cleaning and filling path based on the known boundary and the cleaning area value, and controls the running speed of the axis coordinates according to the set running speed to control the cleaning effect.

[0112] Step S8: After all preparations are complete, turn on the safety switches on the two control boxes, run the program, and the laser cleaning head 30 will begin to move along the X and Z axes according to the main path. At the same time, the sensor group will start working.

[0113] Step S9: Set the cleaning plane position parameters, including the plane angle and plane distance. Three infrared sensors (i.e., the basic ranging sensor 32) are installed on the same mounting plane 31 in an equilateral triangle arrangement. This plane is recorded as the coordinate reference plane S1, and the coordinates of the three sensors are a1(x1, y1, z1), b1(x2, y2, z2), and c1(x3, y3, z3). The center point of a1, b1, and c1 is the origin coordinate O(0, 0, 0). Set virtual points a3(x7, y7, z7), b3(x8, y8, z8), and c3(x9, y9, z9). The calibration plane S2 on which these points are located is parallel to the sensor reference plane, and the distance between the two planes is the effective focal length of the cleaning head. h (i.e., distance) LIn actual operation, the three sensors intersect at three points with the workpiece, determining the actual measurement surface S3. The intersection points are coordinates a2(x4, y4, z4), b2(x5, y5, z5), and c2(x6, y6, z6). Given the fixed coordinates a1, b1, and c1 of the reference surface S1, the fixed coordinates a3, b3, and c3 of the calibration surface S2, and the moving coordinates a2, b2, and c2 of the measurement surface, the angle between surfaces S2 and S3 can be determined by calculating the normal vector according to the plane fitting equation. The calculated angle is converted into system motion compensation. The angle between the reference surface S1 and the measurement surface S2 is adjusted by the cooperation of the v-axis servo motor 27, the u-axis servo motor 29, and the y-axis servo motor 18, keeping them nearly parallel (intersection angle < 5°, i.e., the difference between the angle and the set angle of 0° is less than 5°). The distance measurements of the three basic distance sensors 32 are also calculated. l 1, l 2, l The average value of 3 l 均 According to usage requirements l 均 Must meet l 均 = L ±5%, if not satisfied, then according to l 均 and L The system will use the difference to control the v-axis servo motor 27, u-axis servo motor 29, and y-axis servo motor 18 to perform displacement compensation until the set conditions are met. The above closed-loop calculation is monitored in real time to ensure that the laser cleaning head 30 always maintains the optimal cleaning distance and cleaning angle during the cleaning process.

[0114] Step S10: During equipment operation, the tri-color light 15 remains green; in standby mode, it remains yellow. If a system error occurs or an alarm is triggered, the tri-color light 15 remains red and an alarm sound continuously plays, facilitating the assessment of the machine's operating status. The laser cleaning head 30 has a built-in temperature detection module. In case of abnormally high temperatures, the system automatically shuts down to ensure the safety of the equipment and personnel. The laser cleaning head 30 uses compressed air to maintain the cleanliness of the light outlet.

[0115] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features, or organically combine different embodiments to create the embodiments shown in the accompanying drawings. Of course, those skilled in the art can also create other embodiments not shown in the accompanying drawings. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser cleaning method, characterized in that, a basic rangefinder sensor moving synchronously with the laser cleaning head is used for focusing. There are at least three basic ranging sensors arranged non-collinearly on the same mounting plane. The mounting plane is perpendicular to the principal optical axis of the laser cleaning head. The ranging direction of the basic ranging sensors is parallel to the principal optical axis. The focal plane of the laser cleaning head is defined as the calibration plane. The calibration plane has calibration points corresponding to the basic ranging sensors, and the distance from each calibration point to its corresponding basic ranging sensor is [missing information]. L ; During laser cleaning, each base distance sensor is used to measure the distance from different measuring points on the workpiece surface to the base distance sensor. l Fit all measuring points to the same measuring plane and calculate all distances. l average l 均 The three-dimensional position and tilt angle of the laser cleaning head and the base ranging sensor are adjusted in real time to ensure that the difference between the angle between the measuring plane and the calibration plane and the set angle is always less than 5°, and 0.95 L ≤ l 均 ≤1.05 L The angle is set according to the reflectivity of the workpiece.

2. The laser cleaning method as described in claim 1, characterized in that, Calculate the angle between the measuring plane and the calibration plane based on the coordinates of the calibration point and the measuring point. During adjustment, first adjust the tilt angle of the laser cleaning head and the base distance sensor to ensure that the difference between the angle between the measuring plane and the calibration plane and the set angle is always less than 5°. Then, translate the laser cleaning head and the base distance sensor to make the angle 0.95°. L ≤ l 均 ≤1.05 L .

3. The laser cleaning method as described in claim 1 or 2, characterized in that, Along the extension direction of the main optical axis, the distance from the light beam at the laser cleaning head's output port to the center point of all basic sensors is defined as... H If the beam width at the laser cleaning head's output port is closer to the calibration surface than the center point of all the basic ranging sensors, then L = f + H If the center point of all the basic ranging sensors is closer to the calibration surface than the light beam area at the laser cleaning head's output port, then L = f - H If the center point of all the basic ranging sensors is coplanar with the light beam area at the laser cleaning head's output port, then H =0, L = f In the formula, f This refers to the focal length of the laser cleaning head.

4. The laser cleaning method as described in claim 1 or 2, characterized in that, The basic ranging sensors are distributed at each vertex of the same polygon.

5. The laser cleaning method as described in claim 4, characterized in that, The number of laser cleaning heads is one, and the center point of the polygon is located on the main optical axis of the laser cleaning head; or, the number of laser cleaning heads is at least two, and the center point of the polygon is located on the central axis of the main optical axes of all laser cleaning heads.

6. The laser cleaning method as described in claim 4, characterized in that, There are three basic ranging sensors, and the three basic ranging sensors are located at the three vertices of an equilateral triangle.

7. The laser cleaning method as described in claim 1 or 2, characterized in that, Multiple auxiliary extended ranging sensors are also installed on the mounting plane. The ranging direction of the auxiliary extended ranging sensors is parallel to the main optical axis. The auxiliary extended ranging sensors are arranged around the closed pattern connected to the basic ranging sensor to pre-determine the shape of the surface of the workpiece that needs to be cleaned next during laser cleaning by using the data measured by the auxiliary extended ranging sensors.

8. The laser cleaning method as described in claim 4, characterized in that, Multiple auxiliary extended ranging sensors are also installed on the mounting plane. The ranging direction of the auxiliary extended ranging sensors is parallel to the main optical axis. The auxiliary extended ranging sensors are located on at least two adjacent sides of the top, right, bottom and left sides of the shape enclosed by the basic ranging sensors. On each side where the auxiliary extended ranging sensors are located, some auxiliary extended ranging sensors and some basic ranging sensors form a polygon that is the same as the shape enclosed by all the basic ranging sensors and coincides with one side of the shape enclosed by all the basic ranging sensors.

9. The laser cleaning method as described in claim 1 or 2, characterized in that, Before laser cleaning, the laser cleaning head is moved along the outer contour of the workpiece in the x and z directions, and the outer contour of the workpiece is recorded. During cleaning, the laser cleaning head is controlled to perform an S-shaped reciprocating motion in the x and z directions to clean the entire surface within the outer contour. The y-position and tilt angle of the laser cleaning head are controlled to ensure that the angle between the measuring plane and the calibration plane is always less than 5° and 0.95L ≤ l 均 ≤1.05L.

10. A laser cleaning apparatus, comprising a multi-axis industrial robot and a laser cleaning head mounted on the multi-axis robot as an end effector, the laser cleaning head being equipped with a range sensor that moves synchronously with the laser cleaning head for focusing, characterized in that, There are at least three ranging sensors, which are arranged non-collinearly on the same mounting plane of the multi-axis industrial robot. The mounting plane is perpendicular to the main optical axis of the laser cleaning head, and the ranging direction of the ranging sensors is parallel to the main optical axis. The multi-axis industrial robot is used to synchronously adjust the three-dimensional coordinates and tilt angle of the laser cleaning head and the ranging sensors to implement the laser cleaning method according to any one of claims 1 to 9.

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