CN-121977442-A - Welding eye plate positioning method and system for underwater high-pressure environment

CN121977442ACN 121977442 ACN121977442 ACN 121977442ACN-121977442-A

Abstract

The application relates to a welding eye plate positioning method and a welding eye plate positioning system for an underwater high-pressure environment. The method comprises the steps of calibrating a first tool coordinate system and a second tool coordinate system by a laser range finder and a welding gun which are arranged on a welding robot respectively. The method comprises the steps of establishing an initial workpiece coordinate system for an eye plate under a second tool coordinate system and teaching to obtain a welding program, selecting three non-collinear positioning points of the eye plate under a first tool coordinate system, collecting distance values of points, obtaining initial coordinates by combining with the pose of a robot, constructing the initial pose, obtaining current coordinates again when the pose is triggered to change, calculating the change quantity of the pose, converting the change quantity matrix into the second tool coordinate system according to the calibration relation of the two tool coordinate systems, updating to obtain the current workpiece coordinate system according to the change quantity matrix, and calling the welding program in the coordinate system to finish welding, so that the quick repositioning without re-teaching is realized.

Inventors

HUANG JIQIANG
YUAN WAN
XUE LONG
CAO YINGYU
LIANG YAJUN

Assignees

北京石油化工学院

Dates

Publication Date: 20260505
Application Date: 20260114

Claims (10)

1. A method of locating a welded eye plate for use in an underwater high pressure environment, comprising: the method comprises the steps of calibrating a laser emission end of a laser range finder as a first tool center point to obtain a first tool coordinate system, and calibrating a welding end of a welding gun as a second tool center point to obtain a second tool coordinate system, wherein the laser range finder and the welding gun are both arranged on a welding robot; performing initial calibration on an eye plate to be welded under a second tool coordinate system, establishing an initial workpiece coordinate system corresponding to the eye plate to be welded, and completing teaching programming of a welding path based on the second tool coordinate system and the initial workpiece coordinate system to obtain a welding program; Selecting three non-collinear positioning points on the eye plate to be welded, acquiring distance values of the three positioning points by using a laser range finder under a first tool coordinate system, calculating initial coordinate information of the three positioning points according to the distance values, and constructing an initial pose of the eye plate to be welded under the first tool coordinate system; when the eye plate to be welded meets the pose change triggering condition, acquiring distance values of three positioning points by using a laser range finder under a first tool coordinate system, calculating current coordinate information of the three positioning points according to the distance values, and constructing the current pose of the eye plate to be welded under the first tool coordinate system; Calculating the pose variation of the eye plate to be welded under a first tool coordinate system; Based on the calibration relation between the first tool coordinate system and the second tool coordinate system, performing matrix transformation on the pose change amount of the eye plate to be welded under the first tool coordinate system to obtain the pose change amount of the eye plate to be welded under the second tool coordinate system; Obtaining a current workpiece coordinate system of the eye plate to be welded according to the initial workpiece coordinate system of the eye plate to be welded and the pose variation of the eye plate to be welded under the second tool coordinate system; And calling the welding program in the current workpiece coordinate system of the eye plate to be welded to carry out welding operation on the eye plate to be welded.
2. The method according to claim 1, wherein the method further comprises: Constructing a robot tail end coordinate system; And calibrating the first tool coordinate system and the second tool coordinate system through the robot tail end coordinate system.
3. The method of claim 2, wherein the method comprises performing matrix transformation on the pose change amount of the eye plate to be welded under the first tool coordinate system based on the calibration relation between the first tool coordinate system and the second tool coordinate system, so as to obtain the pose change amount of the eye plate to be welded under the second tool coordinate system, and specifically comprises the following steps: Acquiring a first pose transformation matrix of the first tool coordinate system relative to the robot end coordinate system and a second pose transformation matrix of the second tool coordinate system relative to the robot end coordinate system; Calculating a coordinate transformation matrix from the first tool coordinate system to the second tool coordinate system according to the first pose transformation matrix and the second pose transformation matrix; And representing the pose change quantity of the eye plate to be welded under the first tool coordinate system as a homogeneous pose increment matrix, and performing similar transformation on the homogeneous pose increment matrix based on the coordinate transformation matrix to obtain the pose change quantity of the eye plate to be welded under the second tool coordinate system.
4. A method according to claim 3, wherein the pose change amount includes a rotation change amount and a translation change amount.
5. A method according to claim 3, wherein the obtaining the current workpiece coordinate system of the eye plate to be welded according to the initial workpiece coordinate system of the eye plate to be welded and the pose change of the eye plate to be welded under the second tool coordinate system specifically comprises: constructing a robot base coordinate system; representing the initial workpiece coordinate system as an initial workpiece pose matrix under a robot base coordinate system; And performing matrix synthesis operation on the initial workpiece pose matrix and the pose variation of the eye plate to be welded under a second tool coordinate system to obtain a current workpiece pose matrix of the eye plate to be welded, and inversely converting the current workpiece pose matrix of the eye plate to be welded into a current workpiece coordinate system of the eye plate to be welded under a robot base coordinate system.
6. The method according to claim 1, characterized in that the three positioning points are used for determining the work plane of the eye plate to be welded and its pose in the first tool coordinate system.
7. The method of claim 6, wherein calculating the amount of pose change of the eye plate to be welded in the first tool coordinate system comprises: Determining an initial characteristic plane of an eye plate to be welded based on initial coordinate information of three positioning points, and determining an initial gesture direction according to a normal vector of the initial characteristic plane; determining a current characteristic plane of an eye plate to be welded based on current coordinate information of three positioning points, and determining a current gesture direction according to a normal vector of the current characteristic plane; determining a rotation variable quantity according to the normal vector included angle of the initial characteristic plane and the current characteristic plane, and determining a translation variable quantity according to the corresponding relation between the initial coordinate information and the current coordinate information of the three positioning points; And combining the rotation variable quantity and the translation variable quantity to obtain the pose variable quantity of the eye plate to be welded under the first tool coordinate system.
8. A method according to claim 3, wherein calculating a coordinate transformation matrix of the first tool coordinate system to the second tool coordinate system comprises: And inverting the second pose transformation matrix and multiplying the second pose transformation matrix with the first pose transformation matrix to obtain the coordinate transformation matrix.
9. The method of claim 1, wherein obtaining distance values for three anchor points using a laser rangefinder comprises: and scanning three positioning points on the eye plate to be welded in the XOY plane by using a laser range finder to obtain the distance values of the three positioning points.
10. A welded eye plate positioning system for use in an underwater high pressure environment, comprising: The welding device comprises a welding bin, an eye plate to be welded, a clamping device, a scene monitoring device, a laser range finder, a welding gun, a welding robot, a sliding table and a controller; The welding robot adopts a multi-degree-of-freedom joint structure, and a mounting interface is arranged on a terminal mounting flange and is used for fixing a laser range finder and a welding gun; the sliding table is arranged at the bottom of the welding bin; the eye plate to be welded is fixed in the welding bin through the clamping device; the scene monitoring device is arranged on the inner side of the welding bin and is used for detecting the pose change of the eye plate to be welded; The controller is configured to perform a welding eye plate positioning method for use in an underwater high pressure environment as claimed in any of claims 1-9.

Description

Welding eye plate positioning method and system for underwater high-pressure environment Technical Field The application relates to the technical field of underwater welding, in particular to a welding eye plate positioning method and a welding eye plate positioning system for an underwater high-pressure environment. Background With the increase of the operation demands of installation and maintenance of ocean engineering facilities, emergency rescue and salvage and the like, the cutting, assembly and welding of the underwater structural parts gradually move from shallow water to deep water. In order to improve the safety and welding quality of deepwater operation, a sealed pressure-resistant welding cabin (or operation cabin) is often adopted in engineering to provide a relatively controllable local environment for a welding area, and the positioning and welding of stress connecting members such as eye plates and the like are completed by matching with an underwater robot. The eye plate is usually used as a lifting point, a traction point or a connecting point, and the welding position and the welding gesture of the eye plate directly influence the subsequent lifting, hanging and stress paths, and belong to key welding objects in underwater salvage and underwater installation scenes. In the existing underwater welding robot operation, the welding path is mostly dependent on teaching programming and workpiece coordinate system calibration, namely after the initial position of a workpiece is determined, a tool coordinate system is established through a center point of a welding gun tool, calibration of the workpiece coordinate system is completed, and the teaching is performed under the coordinate relationship to obtain a welding program. The method can obtain better repeatability under the condition of land or stable tooling, but under the conditions of underwater high-pressure environment and operation in a welding cabin, the eye plate to be welded often has non-negligible integral pose change, for example, is influenced by hydrodynamic disturbance, cable traction, buoyancy and counterweight change, salvage swing, elastic deformation of a supporting piece and the like, so that the eye plate is deviated or rotated before or during welding. Once the pose of the workpiece changes relative to the teaching time, the track corresponding to the original welding procedure is not matched with the actual welding seam position, so that the quality problems of welding deviation, undercut, unfused and the like are easy to occur, and collision risks can be caused when the pose of the workpiece is serious, so that the safety of equipment in a welding cabin is influenced. To cope with workpiece misalignment, some solutions attempt to reposition the workpiece using underwater vision or structured light measurements, or to secure the workpiece by mechanical limit clamps. However, under the conditions of high pressure, turbid water body, insufficient illumination, strong metal reflection and the like in a welding cabin, visual measurement is easily influenced by suspended particles, bubbles, welding smoke dust and reflection refraction, stability and measurement precision are difficult to ensure, and a mechanical clamp is highly dependent on field assembly conditions and is difficult to cover random pose changes of an eye plate under different salvage poses. Meanwhile, if the workpiece coordinate system is required to be recalibrated and even the welding path is required to be taught again each time the pose changes, the underwater operation time and the operation complexity are obviously increased, the task efficiency is reduced, and the continuous operation reliability in the deepwater environment is not guaranteed. Disclosure of Invention The application provides a welding eye plate positioning method and a welding eye plate positioning system for an underwater high-pressure environment, which are used for solving the problems that the welding efficiency is low and the welding quality is difficult to guarantee due to the fact that the teaching welding track is not matched with the actual welding seam position and frequent recalibration is needed due to the fact that the overall pose of an eye plate to be welded is easy to deviate in the underwater high-pressure environment in the related technology at least to a certain extent. The scheme of the application is as follows: According to a first aspect of an embodiment of the present application, there is provided a welding eye plate positioning method for an underwater high-pressure environment, including: the method comprises the steps of calibrating a laser emission end of a laser range finder as a first tool center point to obtain a first tool coordinate system, and calibrating a welding end of a welding gun as a second tool center point to obtain a second tool coordinate system, wherein the laser range finder and the welding gun are both arranged on a welding robot; per