Arc welding robot laser vision seam tracking control method based on offline planning

Abstract

The invention relates to an arc welding robot laser vision seam tracking control method based on offline planning. An online robot seam tracking task is completed by combining information such as a prior model of a target to be measured given by seam tracking offline planning, a planned seam tracking movement trace and the like and comprehensively using a sensor detection and predication mechanism, a transmission delay compensation mechanism, an online seam path filtering mechanism and an online 6-dimensional welding trace synthesis mechanism. The sensor planning technology is introduced into offline programming, so that the onsite teaching problem can be solved, and a template of a total solution to entire seam tracking can be provided from the macroscopic aspect on the principle that excellent sensor detection, welding gun welding and robot operating state are ensured by taking the sensor planning technology as a common manner of systematic problem solving. The sensor only needs to effectively correct a part of links of the template on line in real time to finally automatically and symmetrically solve the robot seam tracking problem.

Description

technical field [0001] The invention relates to a method in the application field of robot self-adaptive welding, in particular to a laser vision seam tracking control method for an arc welding robot based on off-line planning. Background technique [0002] Most of the current welding robots belong to the first-generation on-site teaching type or the second-generation off-line programming type, but whether it is on-site teaching programming or off-line planning programming, a key problem will be faced in practical applications It is the adaptability of the compiled program to the actual environment on site, and the main reason for this problem is the change of various actual elements in the on-site welding environment relative to the corresponding ideal elements in programming, especially in the mass production mode. Among them, the unpredictable error in the pose and size of the welding object is the most important reason, including the static change of the weld position an...

AI Technical Summary

Problems solved by technology

[0002] Most of the current welding robots belong to the first-generation on-site teaching type or the second-generation off-line programming type, but whether it is on-site teaching programming or off-line planning programming, a key problem will be faced in practical applications It is the adaptability of the compiled program to the actual environment on site, and the main reason for this problem is the change of various actual elements in the on-site welding environment relative to the corresponding ideal elements in programming, especially in the mass production mode. Among them, the unpredictable error in the pose and size of the welding object is the most important reason, including the static change of the weld position and size caused by the error in processing and assembly, and the heating of the workpiece during the welding process. And the dynamic deformation of the weld bead caused by the change of heat dissipation conditions

There are generally two ways to solve the above problems. One is to reduce the environment and application errors by improving the machining accuracy of the workpiece, improving the assembly accuracy of the tooling fixture, and strictly controlling the robot teaching trajectory. Significantly increase the production and manufacturing costs of enterprises, as well as time consumption costs

Among them, the "on-site teaching type" requires manual teaching of the weld seam in sections considering the constraints of the welding torch and the sensor head at the same time. Therefore, it is difficult to teach some complex or multi-pass weld seams. Disadvantages such as heavy workload, in addition, it requires on-site equipment, and the actual teaching quality is related to the work experience of the operator, which makes this method obviously lack of intelligence and relatively backward

The "autonomous tracking type" generally only needs the operator to perform simple settings according to the characteristics of the welding seam on site, that is, the sensor head guides the welding torch to complete the tracking of the welding seam, although this method can be greatly improved. However, robot welding is a systematic problem that needs to comprehensively consider factors such as welding objects, processes, equipment and the environment, while "autonomous tracking" is to hand over the main control of the entire welding robot to the sensor, but the sensor can only make real-time decisions based on local detection information online to guide the movement of the welding torch, so it not only has blind spots in grasping the surrounding welding environment (there may be collisions between the sensor head and the weldment, or for those with The macro direction of the welding seam with a large curvature cannot be grasped, and it is too late to complete the tracking action), and the upcoming state of the robot is unpredictable (such as the robot is about to enter the joint limit, or fall into the singularity of the work), and for some more complex The adaptability of the welding process is not enough

Images