CN-118106293-B - Laser cleaning method and laser cleaning robot based on visual guidance

CN118106293BCN 118106293 BCN118106293 BCN 118106293BCN-118106293-B

Abstract

The invention discloses a laser cleaning method and a laser cleaning robot based on visual guidance, wherein in the process of cleaning a workpiece to be cleaned, thermal imaging data and laser light intensity signals of the workpiece to be cleaned are obtained, whether a region with temperature exceeding a preset range exists in a current cleaned region or not is judged according to the obtained thermal imaging data, if the region with temperature exceeding the preset range exists, a measured temperature value of the current cleaned region is determined according to the thermal imaging data, a measured light intensity value of the cleaned region is determined according to the laser light intensity signals, the light intensity error value is calculated according to a preset expected light intensity value and the measured light intensity value, the temperature error value is calculated according to the preset expected temperature value and the measured temperature value, adjusted laser power and light intensity are obtained according to the light intensity error value and the temperature error value, and laser is adjusted and cleaned according to the adjusted laser power and light intensity. By implementing the invention, the laser energy can be accurately controlled in real time when the workpiece to be cleaned is cleaned.

Inventors

ZHANG ZHITING
LI LIMING
ZHENG JIANFENG
HUANG XIAOCHUAN
ZHOU YUE
FU TIAN
LIU XIAOFENG

Assignees

深圳众庭联合科技有限公司

Dates

Publication Date: 20260512
Application Date: 20240227

Claims (8)

1. The utility model provides a laser cleaning method based on vision guide, is applicable to laser cleaning robot, characterized by that includes: Acquiring a three-dimensional model of a workpiece to be cleaned; dividing the surface of the workpiece to be cleaned into a plurality of areas to be cleaned according to the three-dimensional model of the workpiece to be cleaned; for each region to be cleaned, calculating a curvature tensor of the region to be cleaned; Calculating a characteristic value corresponding to the curvature tensor and a characteristic vector corresponding to the characteristic value according to the curvature tensor, and confirming a first principal curvature of the region to be cleaned and the characteristic vector corresponding to the first principal curvature according to the characteristic value; according to the feature vector, confirming a first principal curvature direction of the area to be cleaned; Obtaining tangential vectors of the area to be cleaned according to the first principal curvature direction, and calculating a scanning path and a cleaning path corresponding to the scanning path according to each tangential vector information, wherein the laser cleaning robot comprises a laser cleaning head for performing laser cleaning on a workpiece to be cleaned; According to the scanning path and the cleaning path, the laser cleaning head is controlled to rotate, so that the workpiece to be cleaned is cleaned; In the process of cleaning a workpiece to be cleaned, acquiring thermal imaging data and laser light intensity signals of the workpiece to be cleaned; judging whether a region with the temperature exceeding a preset range exists in the current cleaned region according to the acquired thermal imaging data; If the measured temperature value exists, determining a measured temperature value of the current cleaned area according to the thermal imaging data, and determining a measured light intensity value of the cleaned area according to the laser light intensity signal; Calculating a light intensity error value according to a preset expected light intensity value and a measured light intensity value, and calculating a temperature error value according to a preset expected temperature value and a measured temperature value; obtaining adjusted laser power and light intensity according to the light intensity error value and the temperature error value, and adjusting the laser according to the adjusted laser power and light intensity; And cleaning the current cleaned area according to the adjusted laser.
2. The vision-guided laser cleaning method of claim 1, further comprising: judging whether a secondary cleaning area exists in the cleaned area according to the acquired thermal imaging data of the workpiece to be cleaned, wherein the secondary cleaning area comprises an area with the temperature continuously higher than a preset temperature value in a preset time period and an area with the temperature fluctuation exceeding a preset fluctuation range; And if the cleaning agent exists, performing secondary cleaning on the secondary cleaning area.
3. The vision-guided laser cleaning method of claim 2, wherein the laser cleaning robot further comprises a three-dimensional scanner and a positioner; Before the three-dimensional model of the workpiece to be cleaned is acquired, the method further comprises the steps of: Determining a base coordinate system of the internal space of the laser cleaning robot; Confirming a first coordinate transformation relation between the laser cleaning robot base and the three-dimensional scanner according to the mark points with known space coordinates and the base coordinate system; Confirming a second coordinate transformation relation between the laser cleaning robot base and the laser cleaning head according to a known plane and the base coordinate system; confirming a positioner overturning shaft calibration parameter and a rotating shaft calibration parameter according to the base coordinate system; And respectively unifying the coordinate system of the three-dimensional scanner, the coordinate system of the laser cleaning head and the coordinate system of the positioner with the base coordinate system according to the base coordinate system, the first coordinate transformation relation, the second coordinate transformation relation, the positioner overturning shaft calibration parameter and the positioner rotating shaft calibration parameter.
4. The vision-guided laser cleaning method of claim 3, wherein the three-dimensional scanner comprises a binocular camera; the obtaining the three-dimensional model of the workpiece to be cleaned comprises the following steps: according to the pre-modulated structured light pattern, a left image of a workpiece to be cleaned, which is acquired by a left-eye camera, and a right image of the workpiece to be cleaned, which is acquired by a right-eye camera, are acquired in the binocular camera; Performing space decoding on the left image and the right image to obtain a restored left image and a restored right image; According to the preset polar geometry and the stereoscopic vision polar constraint, fusing the restored left image and the restored right image to obtain a fused stereoscopic image of the workpiece to be cleaned; calculating three-dimensional coordinates of the workpiece to be cleaned according to calibration parameters of the camera, preset system parameters and the three-dimensional image of the workpiece to be cleaned, and generating a three-dimensional model of the workpiece to be cleaned according to the three-dimensional coordinates.
5. The vision-guided laser cleaning method of claim 4, wherein calculating a scan path and a cleaning path corresponding to the scan path from each of the tangent vector information comprises: Calculating the angle to be rotated of the laser cleaning head and a measuring track corresponding to the angle to be rotated according to the tangential vector information; under the condition that the measurement track reaches a preset condition, taking the measurement track as a scanning path, and determining a cleaning path corresponding to the scanning path according to the scanning path; the preset conditions include that the measuring track is opposite to the measuring head of the three-dimensional scanner, and the overlapping area of laser beams emitted by the laser cleaning head when the laser cleaning head moves along the measuring track is lower than a preset value.
6. A vision-guidance-based laser cleaning robot, which is characterized by performing the vision-guidance-based laser cleaning method according to any one of claims 1 to 5, and comprises a sensing module, a laser cleaning head and a control module, wherein the sensing module comprises a PD energy detector and a thermal imaging camera, and the control module comprises a master controller, a thermal imaging controller and a light intensity controller; The PD energy detector is used for acquiring a laser light intensity signal of a workpiece to be cleaned and feeding the laser light intensity signal back to the control module; The thermal imaging camera is used for acquiring thermal imaging data of a workpiece to be cleaned and feeding the thermal imaging data back to the control module; The master controller is used for judging whether the current cleaned area has an area with the temperature exceeding a preset range according to the acquired thermal imaging data, if so, determining the measured temperature value of the current cleaned area according to the thermal imaging data, and determining the measured light intensity value of the cleaned area according to the laser light intensity signal; The light intensity controller is used for calculating a light intensity error value according to a preset expected light intensity value and a measured light intensity value; the thermal imaging controller is used for calculating a temperature error value according to a preset expected temperature value and a measured temperature value; The laser cleaning head is used for cleaning the workpiece to be cleaned according to the adjusted laser.
7. The vision-guided laser cleaning robot of claim 6, further comprising a three-dimensional scanner; The three-dimensional scanner is used for scanning the workpiece to be cleaned and constructing a three-dimensional model of the workpiece to be cleaned according to the data obtained by scanning.
8. The vision-guided laser cleaning robot of claim 6, further comprising a motion module; the motion module comprises a mechanical arm and a positioner; The mechanical arm is used for driving the laser cleaning head to move according to a cleaning path so that the laser cleaning head can perform laser cleaning according to the cleaning path; and the position changer is used for rotating until the laser cleaning head can clean according to the cleaning path when the laser cleaning head still cannot clean according to the cleaning path after the mechanical arm moves.

Description

Laser cleaning method and laser cleaning robot based on visual guidance Technical Field The invention relates to the field of robots, in particular to a laser cleaning method based on visual guidance and a laser cleaning robot. Background At present, the existing laser cleaning technology still needs a great deal of manual assistance in the cleaning process, a manual teaching-memory reproduction mode is generally adopted to complete the cleaning task, and the capability of sensing and adjusting the cleaning process in real time is lacking, so once the environmental conditions change, the laser cleaning equipment cannot automatically adjust parameters to adapt to the changes, thereby leading to unstable cleaning effect, in addition, the existing laser cleaning technology has limited adaptability to certain complex surfaces, the laser cleaning equipment cannot accurately judge the required cleaning parameters, thereby leading to the cleaning robot not being capable of adjusting the power and the light intensity of the laser in real time by sensing the surface condition of the workpiece to be cleaned, leading to poor cleaning effect of the workpiece to be cleaned, and therefore, how to improve the cleaning effect by sensing the surface condition of the workpiece to be cleaned in real time in the laser cleaning process is a problem to be solved. Disclosure of Invention The invention provides a laser cleaning method and a laser cleaning robot based on visual guidance, wherein the method can accurately control laser energy in real time when a workpiece to be cleaned is cleaned, so that when the environment conditions are changed and the surface is complex, parameters are automatically adjusted to adapt to the changes, the cleaning effect of the surface of the workpiece to be cleaned is consistent, and the surface of the workpiece is ensured to be accurately treated in the cleaning process. An embodiment of the invention provides a laser cleaning method based on visual guidance, which comprises the following steps: In the process of cleaning a workpiece to be cleaned, acquiring thermal imaging data and laser light intensity signals of the workpiece to be cleaned; judging whether a region with the temperature exceeding a preset range exists in the current cleaned region according to the acquired thermal imaging data; If the measured temperature value exists, determining a measured temperature value of the current cleaned area according to the thermal imaging data, and determining a measured light intensity value of the cleaned area according to the laser light intensity signal; Calculating a light intensity error value according to a preset expected light intensity value and a measured light intensity value, and calculating a temperature error value according to a preset expected temperature value and a measured temperature value; obtaining adjusted laser power and light intensity according to the light intensity error value and the temperature error value, and adjusting the laser according to the adjusted laser power and light intensity; And cleaning the current cleaned area according to the adjusted laser. Further, the vision guidance-based laser cleaning method further comprises the following steps: judging whether a secondary cleaning area exists in the cleaned area according to the acquired thermal imaging data of the workpiece to be cleaned, wherein the secondary cleaning area comprises an area with the temperature continuously higher than a preset temperature value in a preset time period and an area with the temperature fluctuation exceeding a preset fluctuation range; And if the cleaning agent exists, performing secondary cleaning on the secondary cleaning area. Further, the laser cleaning robot comprises a laser cleaning head for performing laser cleaning on a workpiece to be cleaned; Before acquiring thermal imaging data and laser light intensity signals of the workpiece to be cleaned in the process of cleaning the workpiece to be cleaned, the method comprises the following steps: Acquiring a three-dimensional model of the workpiece to be cleaned; Dividing the surface of the workpiece to be cleaned into a plurality of areas to be cleaned according to the three-dimensional model of the workpiece to be cleaned; Calculating the tangent vector of each region to be cleaned, and calculating a scanning path and a cleaning path corresponding to the scanning path according to the tangent vector information; And controlling the laser cleaning head to rotate according to the scanning path and the cleaning path, so as to clean the workpiece to be cleaned. Further, the laser cleaning robot also comprises a three-dimensional scanner and a positioner; Before the three-dimensional model of the workpiece to be cleaned is acquired, the method further comprises the steps of: Determining a base coordinate system of the internal space of the laser cleaning robot; Confirming a first coordinate transformation relation between