Overview

In the aerospace industry, FODs are a recurrent problem that implies a high risk. This package has been developed to help identifying FODs in aeronautical structures.

Using point cloud analysis techniques, this software aims to compare the current state of the structure with its CAD to identify possible foreign objects.

NOTE: the following release is an alpha experimental release corresponding to Milestone 1 of the ROSIN project.

Getting started

Source: git https://github.com/fada-catec/leica_point_cloud_processing (branch: master)

This package have been designed to be used in combination with the leica_scanstation package, which allows to control the scanstation to scan an aeronautical part. When the scan is finished, you get the point cloud that proceeds to be analyzed.

However, it is possible to feed this program with pointclouds from other sources and it will run the same way.

NOTE: you will need leica_scanstation_msgs and leica_scanstation_utils packages from leica_scanstation to use this one.

Workflow

The aim is to compare two pointclouds: the one obtained after scanning with the Leica Scanstation, with the ideal one obtained directly from CAD. The first stage is to align both clouds by using algorithms such us GICP.

Then, comparation is done and the system returns point clouds that represent possible FODs.

workflow.png

Usage

Publish clouds

load_and_publish_clouds node will load both scanned and CAD clouds into ROS environment.

 rosrun leica_point_cloud_processing load_and_publish_clouds

Considerations:

  • Make sure pointcloud files are on the correct folder, specified in ROS param server as /pointcloud_folder (default: package leica_scanstation_utils/pointclouds).

  • Supported formats: .obj for CAD files and .pcd for scanned files. NOTE: both files must have the same name.

  • Publisher starts when service /publish_clouds is called: automatically done by leica_scanstation_ros_node when scan is finished or manually by user:

     rosservice call /publish_clouds "file_name: '{file}'"

Start process

node is the main node that perform alignment and FOD detection. It opens subscribers to clouds topics and start process.

 rosrun leica_point_cloud_processing node
  • Once alignment process is finished we recomend to see results in RViz. It is possible to modify results doing more iterations of GICP algorithm:
     rosservice call /iterate_gicp
     rosservice call /undo_iteration
  • When results are good enough, search for FODs:
     rosservice call /get_fods
  • To restart the program with different pointclouds:
     rosservice call /stop_alignment

Code API

Topics

cad/cloud (sensor_msgs/PointCloud2)

  • Point cloud created from loading Part's CAD.
scan/cloud (sensor_msgs/PointCloud2)
  • Point cloud obtained from loading the result of a scanning process.
cad/cloud_filtered (sensor_msgs/PointCloud2)
  • CAD Point cloud after downsampling.
scan/cloud_aligned (sensor_msgs/PointCloud2)
  • Point cloud resulting of the aligned cloud.
num_of_fods (std_msgs/Int16)
  • Number of FODs detected in cloud
fod0 (sensor_msgs/PointCloud2) fod1 (sensor_msgs/PointCloud2) fod2 (sensor_msgs/PointCloud2)

...

It will create a topic for each FOD detected.

Services

publish_clouds (leica_scanstation_msgs/PointCloudFile)

  • Tell which pointcloud file to publish into ROS environment.
iterate_gicp (std_srvs/Trigger)
  • Ask for GICP algorithm to do a new iteration of the aligment process.
undo_iteration (std_srvs/Trigger)
  • Restore cloud previous to last iteration.
get_fods (std_srvs/Trigger)
  • Start process to search for FODs.
stop_alignment (std_srvs/SetBool)
  • Stop current alignment process and restart the program subscribing again to pointclouds.

Acknowledgement

ROSIN Logo

Supported by ROSIN - ROS-Industrial Quality-Assured Robot Software Components.
More information: rosin-project.eu

EU Flag

This project has received funding from the European Union’s Horizon 2020
research and innovation programme under grant agreement No. 732287.

Wiki: leica_point_cloud_processing (last edited 2020-07-31 13:12:34 by Fada_Catec)