Large plate centering grabbing and positioning method for LNG (Liquefied Natural Gas) ship

Abstract

The invention discloses an LNG (Liquefied Natural Gas) ship large plate centering, grabbing and positioning method, one side of a workpiece is provided with a laser range finder, and the method comprises the following steps: S1, measuring the distance X between the side end face of the workpiece with the known length of Y and the laser range finder, and calibrating the center point of the workpiece according to the numerical values of X and Y, the distance between the center point and the laser range finder being Y / 2 + X; s2, a plurality of workpieces with the length being Y1 are placed on the foot pads in a stacked mode; s3, the actual distance X1 between the laser range finder and the side end face of the workpiece is measured; and S4, the offset of the clamping jaw is adjusted according to the relative position between the actual center point position of the workpiece and the calibrated center point position, and the offset adjustment value is (Y1 / 2 + X1)-(Y / 2 + X). According to the invention, centering grabbing and positioning of the large plate can be realized without arranging an additional mechanical centering positioning table, the occupied area is small, the operation is simple, and the efficiency is higher.

Description

Technical Field

[0001] This invention relates to the field of LNG ship manufacturing technology, and more specifically to a method for centering and positioning large plates for LNG ships. Background Technology

[0002] LNG carrier large plate centering and positioning refers to the process of accurately grabbing and positioning large plates (such as insulation plates and anchor plates of the liquid tank containment system) to a designated position during the construction or maintenance of LNG carriers, using specific technologies and equipment, to ensure installation accuracy and construction quality.

[0003] Due to production process requirements, the workpiece needs to be gripped along its length and centered. The existing technology involves a robot gripper gripping the workpiece and then placing it on a mechanical centering and positioning table. After the positioning table is in place, the robot then performs the centering gripping. This process is inefficient, involves more mechanical equipment, occupies more space, requires higher investment, and has a cumbersome workflow.

[0004] Therefore, how to provide a positioning method that can accurately center and grasp a large plate for LNG ships is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method for centering and positioning a large plate for LNG ships, aiming to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for centering and positioning a large plate for LNG ships, wherein a laser rangefinder is installed on one side of the workpiece, includes the following steps: S1. Measure the distance X between the side end face of the workpiece with a known length Y and the laser rangefinder. Based on the values ​​of X and Y, determine the center point of the workpiece. The distance between the center point and the laser rangefinder is Y / 2+X. S2. Stack multiple workpieces of length Y1 on the pads; S3. Measure the actual distance X1 between the laser rangefinder and the side end face of the workpiece; S4. Adjust the offset of the gripper according to the relative position between the actual center point of the workpiece and the calibrated center point. The offset adjustment value is (Y1 / 2+X1)-(Y / 2+X).

[0007] The beneficial effect of the technical solution of the present invention is that, by calibrating the center point of a workpiece of known length, when grasping multiple stacked workpieces, the center point of the workpiece to be grasped can be calculated based on the position of the center point and the distance between the side end face of the workpiece to be grasped and the laser rangefinder. The position of the gripper is corrected based on the center point of the workpiece to be grasped, thereby achieving centered grasping and positioning.

[0008] Preferably, in step S2, multiple workpieces are stacked on pads using a forklift or automated AGV device, and the number of layers is transmitted to the control center.

[0009] Preferably, after the workpiece is placed on the pad, the angle of the workpiece is adjusted by the gripper so that its side end face is perpendicular to the irradiation path of the laser rangefinder.

[0010] Preferably, in step S4, if the adjustment value is negative, the gripper is adjusted along the direction of the laser rangefinder; if the adjustment value is positive, the gripper is adjusted in a direction away from the laser rangefinder.

[0011] Preferably, when the length Y1 of the workpiece is the same as the length Y of the sheet metal, the adjustment value is X1-X; when the length Y1 of the workpiece is different from the length Y of the sheet metal, the adjustment value is (Y1-Y) / 2+X1-X.

[0012] Preferably, a column is fixed to one side of the pad, and a lead screw is rotatably connected to the side wall of the column; the laser rangefinder is fixed to the nut on the lead screw and can move up and down to the center of the side end face of the workpiece in each layer.

[0013] Preferably, a servo motor is fixed to one end of the lead screw to drive the rotation of the lead screw.

[0014] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method for centering and positioning large plates for LNG ships, which can achieve centering and positioning of large plates without setting up an additional mechanical centering and positioning platform, occupying less space, being simple to operate, and being more efficient. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] Figure 1 This is a schematic diagram illustrating the principle of centering and gripping the board provided by the present invention. Figure 2 This is a schematic diagram of the workpiece provided by the present invention.

[0017] Among them, 1-workpiece; 11-moving side of gripper; 12-fixed side of gripper; 2-foot pad; 3-column; 4-lead screw; 5-laser rangefinder; 6-servo motor. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] See appendix Figure 1 and 2 According to an embodiment of the present invention, a method for centering and positioning a large LNG ship plate is provided. A laser rangefinder 5 is provided on one side of the workpiece 1. The laser rangefinder 5 is driven to move up and down by a lead screw 4. Specifically, a column 3 is fixed on one side of the foot 2, and the lead screw 4 is rotatably connected to the side wall of the column 3. The laser rangefinder 5 is fixed to the nut on the lead screw 4 and can move up and down to the center of the side end face of the workpiece 1 corresponding to each layer. A servo motor 6 is fixed to one end of the lead screw 4 to drive the rotation of the lead screw 4. The method includes the following steps: S1. Measure the distance X between the side end face of the workpiece 1 with a known length Y and the laser rangefinder 5. Based on the values ​​of X and Y, determine the center point of the workpiece. The distance between the center point and the laser rangefinder 5 is Y / 2+X. One side of workpiece 1 is the fixed gripper side 12, and the other side is the movable gripper side 11. When positioning a rectangular plate-shaped workpiece, the center point is calibrated along the long axis of workpiece 1. After the center point is calibrated, the distance a=b between the two sides of the gripper position on the movable gripper side 11 or the fixed gripper side 12.

[0020] S2. Place multiple workpieces 1 of length Y1 on the pad 2; Multiple workpieces 1 are stacked on pads 2 using a forklift or automated AGV device, and the layer count is transmitted to the control center. After workpiece 1 is loaded, there will be an error of ±50mm between the workpiece 1 to be picked up and the calibrated center point. In this case, a≠b, so the center point needs to be corrected. The specific method is as follows: After the workpiece 1 is placed on the pad 2, the angle of the uppermost workpiece 1 to be gripped is adjusted by the gripper so that its side end face is perpendicular to the irradiation path of the laser rangefinder 5.

[0021] The fixed end of the gripper is pressed against the fixed side 12 of the gripper on the workpiece 1, and the movable end of the gripper clamps the movable side 11 of the gripper on the workpiece 1. The angle of the workpiece 1 is adjusted so that its side end face can be perpendicularly illuminated by the laser rangefinder 5.

[0022] S3. Measure the actual distance X1 between the laser rangefinder 5 and the side end face of the workpiece 1; S4. Adjust the offset of the gripper according to the relative position between the actual center point of workpiece 1 and the calibrated center point. The offset adjustment value is Y1 / 2 + X1 - Y / 2 + X. When the length Y1 of workpiece 1 is the same as the length Y of the sheet material, the adjustment value is X1 - X; when the length Y1 of workpiece 1 is different from the length Y of the sheet material, the adjustment value is (Y1 - Y) / 2 + X1 - X. After calculating the adjustment value, offset the gripper according to the adjustment value to correct the position of the center point of workpiece 1 and ensure that the gripper can be centered and gripped.

[0023] To further optimize the above technical solution, in step S4, if the adjustment value is negative, the gripper is adjusted along the direction of the laser rangefinder 5; if the adjustment value is positive, the gripper is adjusted away from the laser rangefinder 5.

[0024] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0025] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for centering and positioning a large LNG ship plate, characterized in that, A laser rangefinder (5) is provided on one side of the workpiece (1), including the following steps: S1. Measure the distance X between the side end face of the workpiece (1) with a known length of Y and the laser rangefinder (5). Based on the values ​​of X and Y, mark the center point of the workpiece. The distance between the center point and the laser rangefinder (5) is Y / 2+X. S2. Place multiple workpieces (1) of length Y1 on the pad (2); S3. Measure the actual distance X1 between the laser rangefinder (5) and the side end face of the workpiece (1); S4. Adjust the offset of the gripper according to the relative position between the actual center point of the workpiece (1) and the calibrated center point. The offset adjustment value is (Y1 / 2+X1)-(Y / 2+X).

2. The method for centering and positioning a large LNG ship plate according to claim 1, characterized in that, In step S2, multiple workpieces (1) are stacked on pads (2) by a forklift or an automated AGV device, and the number of layers is transmitted to the control center.

3. The method for centering and positioning a large LNG ship plate according to claim 2, characterized in that, After the workpiece (1) is placed on the pad (2), the angle of the workpiece (1) is adjusted by the gripper so that its side end face is perpendicular to the irradiation path of the laser rangefinder (5).

4. The method for centering and positioning a large LNG ship plate according to claim 1, characterized in that, In step S4, if the adjustment value is negative, the gripper is adjusted along the direction of the laser rangefinder (5); if the adjustment value is positive, the gripper is adjusted away from the laser rangefinder (5).

5. The method for centering and positioning a large LNG ship plate according to claim 4, characterized in that, When the length Y1 of the workpiece (1) is the same as the length Y of the plate, the adjustment value is X1-X; when the length Y1 of the workpiece (1) is different from the length Y of the plate, the adjustment value is (Y1-Y) / 2+X1-X.

6. The method for centering and positioning a large LNG ship plate according to claim 1, characterized in that, A column (3) is fixed on one side of the foot (2), and a screw (4) is rotatably connected to the side wall of the column (3); the laser rangefinder (5) is fixed to the nut on the screw (4) and can move up and down to the center of the side end face of the workpiece (1) of each layer.

7. A method for centering and positioning a large LNG ship plate according to claim 6, characterized in that, A servo motor (6) is fixed to one end of the lead screw (4) to drive the rotation of the lead screw (4).

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