Patent ID: 11969826
Assignee: nan
Field: Machine tools (Mechanical engineering)
Classification: CPC B  Y | IPC B

Claim 0:
1. A robot-based laser cladding method for membrane wall, comprising:
step 1: installing a laser line scanning sensor and a laser cladding head in parallel with a forward-bias between the laser line scanning sensor and the laser cladding head in a feed direction, wherein a distance of the forward-bias is determined based on a disturbance of cladding powder and splash; installing an industrial camera to make the industrial camera lag behind the laser cladding head in an installation space by a bias distance and to make the industrial camera to have a certain angle relative to the laser cladding head, wherein a collection range of the industrial camera is within 15 millimeters (mm) from a current cladding position; online tracking and scanning a contour of a membrane wall of a previous melt channel by using the laser line scanning sensor, and executing a feature point extraction task to extract feature points defining a trail of a current melt channel, wherein a thermal deformation generated by the previous melt channel tends to deform the contour of the membrane wall, the laser line scanning sensor is configured to extract the feature points in an online tracking and scanning manner, and the thermal deformation generated by the previous melt channel is determined based on information of the feature points under the online tracking and scanning manner;
step 2: storing the extracted feature points into a feature point buffer sequentially, fitting directly adjacent numbered feature points in the feature point buffer through line segments; in order to prevent the existence of an angle between line segments, being greater than a threshold θmax and limiting a cladding speed after the line segment fitting, executing a line segment smooth task, wherein the line segment smooth task refers to introducing a transition arc into a position corresponding to an angle greater than the threshold θmax between the line segments, to achieve an arc transition and improve a processing speed, some of the line segments are inserted with arc segments to make corresponding starting or ending positions of the some of the line segments and line segment types of the some of the line segments change; refreshing information of the line segments after performing the line segment smooth task, wherein the refreshed line segments form a cladding trail; and then executing a read-ahead segment number determination task to determine a prospective segment number N, after determining the prospective segment number N, reading from a current i-th segment to an i+N-th segment in the feature point buffer during performing a speed planning, determining an ending speed of each of the line segments by performing the speed planning, and executing a speed planning task to implement a speed planning of each of the line segments in the cladding trail;
step 3: after an image is collected by the industrial camera, performing a noise reduction for the image through a Gaussian filter; improving a contrast ratio of the image through a gamma image enhancement technology; obtaining a target pixel division threshold by using an Otsu binarization technology; segmenting out a target foreground area by using the target pixel division threshold, wherein the target foreground area refers to an area corresponding to the previous melt channel and the current melt channel within a field of view of the industrial camera; extracting edge positions of the previous melt channel and the current melt channel to achieve a detection purpose; collecting overlapping information between the current melt channel and the previous melt channel and calculating an overlapping rate β based on the overlapping information; in a situation that the overlapping rate β is not within a threshold range (βmin, βmax), executing an interpolation and correction task to correct an interpolation result of a next line segment, transmitting in real-time a corrected value to each of shafts of a robot for implementing correction of the cladding trail; compensating an effect of a thermal deformation of a line segment being clad by the current melt channel on a next line segment to-be-clad by the current melt channel by using the overlapping information collected by the industrial camera; and implementing a dynamic correction of the cladding trail to achieve a laser cladding for the membrane wall.