The application of Radian laser tracker in the field of large hatch docking assembly

summary

Large cabin sections are often characterized by huge size and weight. However, at the same time, the final assembly accuracy of large cabin sections usually has high requirements, and its docking accuracy will affect the final quality of the whole cabin section. In practice, there are plans to improve the final assembly accuracy by improving the processing accuracy, but the implementation is very harsh and difficult; The more effective method is to support the smooth implementation of the whole assembly process by improving and optimizing the assembly method.

API high-precision measurement docking scheme
Combining the characteristics and assembly requirements of large cabin sections, the application of automatic docking technology based on API brand Radian Laser Tracker can effectively improve the assembly accuracy and efficiency.

API solution, as shown in Figure 1, is to deploy the Radian laser tracker next to the mobile end tank section, monitor the position and attitude of the marker points on the cylinder surface during the actual assembly process of most of the cylinders, compare the position and attitude of the mobile end tank section with the results after the virtual assembly, and according to the conversion matrix, the rotation, translation and other parameters can be obtained and fed back to the control mechanism, In this way, the actual assembly results can be consistent with the virtual assembly results.

Specific implementation and operation
Use Radian laser tracker to accurately measure the flange mounting surface and pin hole to obtain the true three-dimensional state of the measured end face; At the same time, the laser tracker is used to monitor the assembly process of most parts; A number of monitoring control points are arranged on one side of the connecting flange. These control points can be measured by the laser tracker at the same time. Through conversion, the relative position and attitude relationship of the mating flange surfaces of the two sections can be obtained, and the real-time position and attitude of the mobile end can be uploaded to the upper computer. After the upper computer obtains the position and attitude of the mobile end, the data it needs to adjust can then be fed back to the control and adjustment mechanism, So as to realize the closed-loop automatic docking function.

Through the above high-precision measurement, the relevant dimensions of the fixed end and the mobile end are obtained. The docking process of closed-loop control is to obtain the deviation matrix of the current position and attitude through the comparative analysis of the target coordinate system on the basis of the previous reference coordinate system. Each deviation given is the adjustment amount of the current position and attitude and the target position and attitude. It can be realized in four steps:

1. Measure and establish the coordinate system of feedback mechanism
2. Create the target coordinate system. First, create the mobile end coordinate system, and then use the feedback mechanism coordinate system as the working coordinate system to use the move command. The source coordinate system is selected as the mobile end coordinate system, the object coordinate system is selected as the fixed end coordinate system, and the coordinate system to be converted is selected as the feedback mechanism coordinate system. The target coordinate system is obtained by moving and changing the coordinate system.
3. Use 6D navigation software to monitor 3 observation points in real time.
4. Through the inquiry and command of the upper computer, the tracker automatically measures the target balls at three identification points, obtains the adjustment amount of the current position and posture, and completes the closed-loop control. The docking operation was successfully completed through 3-4 adjustments.

conclusion
The application of automatic docking technology of Radian laser tracker can effectively improve the accuracy and efficiency of large cabin assembly.